1816368
How to Be a Male at Different Elevations: Ecology of Intra-Sexual Segregation in the Trawling Bat Myotis daubentonii
Intra-sexual segregation is a form of social segregation widespread among vertebrates. In the bat Myotis daubentonii, males are disproportionately abundant at higher elevations, while females are restricted to lower altitude. Intra-male segregation is also known to occur yet its ecological and behavioural determinants are unclear. We studied male segregation along a river in Central Italy where we tested the following predictions: 1. Upstream ( > 1000 m a.s.l.) males will rely on scarcer prey; 2. To deal with this limitation and exploit a cooler roosting environment, they will employ more prolonged and deeper torpor than downstream (< 900 m a.s.l.) males; 3. Body condition will be better in downstream males as they forage in more productive areas; 4. To cope with less predictable foraging opportunities, upstream males will use more habitat types. Consistent with our predictions, we found that prey were less common at higher altitudes, where bats exhibited prolonged and deeper torpor. Body condition was better in downstream males than in upstream males but not in all summer months. This result reflected a decrease in downstream males’ body condition over the season, perhaps due to the energy costs of reduced opportunities to use torpor and/or intraspecific competition. Downstream males mainly foraged over selected riparian vegetation whereas upstream males used a greater variety of habitats. One controversial issue is whether upstream males are excluded from lower elevations by resident bats. We tested this by translocating 10 upstream males to a downstream roost: eight returned to the high elevation site in 1-2 nights, two persisted at low altitude but did not roost with resident bats. These results are consistent with the idea of segregation due to competition. Living at high altitude allows for more effective heterothermy and may thus be not detrimental for survival, but by staying at lower altitude males increase proximity to females and potentially benefit from summer mating opportunities.
2030387
Unexplained sexual segregation in polygamous ungulates: a defense of an ontogenetic approach
Two processes are generally mixed when considering ungulate sexual segregation: the social segregation which appears to be a rule in polygamous ungulate species and the spatial segregation which is facultative. Early in life, there is evidence that males and females exhibit different levels of activity and patterns of interaction which could lead to behavioural incompatibility. It is proposed that juvenile females, differently motivated than males to interact socially, may soon avoid the pseudo-sexual and agonistic male behavioural components. as body and behavioural dimorphism increase with age, the behavioural incompatibility would be intensified. Since adults often interact agonistically with or avoid them, juveniles will attend to interact with same-sex peers of similar status. Because social experiences are occurring since early stages of development, i.e., during sensitive periods, a social auto-segregation by sex/age classes is expected. Then population would be structured in coherent socio-spatial sets of compatible individuals, sharing similar constraints and properties. Around the birth period, females become asocial promoting a temporal social segregation. Costs linked to gestation and lactation may make females more dependent on water and rich food resources. Female with offspring are also likely to select areas where the risks of predation are reduced, sometimes at detriment to energy intake, while other animals exhibit opportunistic feeding behaviour, resulting in seasonally ecological segregation. Body growth channels a lot of energy for males which are expected to use the best feeding areas. However, indirect competition for the same resources may result in a spatial segregation between the sexes. Sex- and age-specific activity budgets are suspected to favour social and spatial segregations. The social segregation among males and females use exclusive ranges. Whether spatial segregation results in ecological segregation would however depend on habitat heterogeneity, population density, local ecological conditions and the biological cycle periods. It is suggested that spatial segregation will occur not only between the sexes but also among males. If populations are structured in coherent socio-spatial units, spatial segregation among individuals of age and sex classes may result from indirect interactions between sets of individuals (of same age and sex class), that may be translated as an indirect competition between individuals. Studies on ethogenesis are considered as fundamental as they allow to know on what basis social and spatial segregations are set up. In particular, studies on behavioural development could highlight how social segregation between adults may result from a process that originates much earlier in the life of animals. By considering the role of behaviour, we defend the idea that social and spatial segregations may be logically distinguished.
8609588
Multiple causes of sexual segregation in European red deer: enlightenments from varying breeding phenology at high and low latitude
Sexual segregation outside the mating season occurs in most species of sexually dimorphic ungulates and has been extensively described in the literature, but the mechanisms causing segregation are still debated. The detailed pattern of sexual segregation throughout the year has rarely been presented for mammals, and no study, to our knowledge, has used latitudinal–related variation in breeding phenology to shed light on the underlying mechanisms. Recent methodological developments have made it possible to quantify separate components of segregation (social, habitat) and activity synchrony in animal groups, but these major improvements have so far been little used. We observed European red deer year round at two widely different latitudes (France and Norway) and tested three different mechanistic hypotheses of segregation related to: (i) predation risk; (ii) body–size–related forage selection; and (iii) activity budget. Habitat segregation peaked during calving in both populations and dropped rapidly after calving. Females with calves were more segregated from males than were females without calves, pointing to a key role of anti–predator behaviour even though large predators are absent in France and extremely rare in Norway. However, at both sites individuals also grouped with their own sex within habitat types (i.e. social segregation), and individuals in mixed–sex groups were less synchronized in activity type than individuals in either unisex male or unisex female groups, suggesting that differences in activity budgets are involved. Social segregation peaked during calving and was lowest during the rut (indicating aggregation) in both populations; these activities occurred one month later in the Northern populations, corresponding well with known differences in breeding phenology. We conclude that latitude–dependent breeding phenology shapes the seasonal pattern of sexual segregation and that sexual segregation in ungulates has multiple causes.
3139519
Sexual segregation in vertebrates: proximate and ultimate causes.
Sexual segregation is very common in vertebrates that live in groups. In this article, I will review proximate and ultimate causes of sexual segregation in social species and in particular in ungulates in which the bulk of research on the topic has been carried out. In most social ungulate species, males and females live in separate groups outside the breeding season, sometimes using different home ranges and types of habitat. In most of these species, males are larger than females. Dimorphism in body size can lead to sexual differences in ecology and behavior making it difficult for the two sexes to stay in the same group. It is important for our better understanding of the evolution of sociality, sexual dimorphism and different mating systems to determine why sexual segregation is so widespread not only in ungulates but also in other vertebrates. In this article, I discuss the ecology of the two sexes by reviewing proximate and ultimate causes of sexual segregation. To do this, I compare a range of studies of ruminants and include explanations for social segregation as well as for habitat segregation by gender. This leads into a review and updates current knowledge of the phenomenon. Although I present a number of different hypotheses, I focus in particular on predation risk, forage selection and activity budget and discuss the social-factors hypothesis. I stress that the key in solving the enigma of sexual segregation lies in clearly separating hypotheses that try to explain social segregation and habitat segregation, as well as in including experiments or model systems. To that end, I present a preliminary study on a test of the activity-budget hypothesis in three-spine sticklebacks and explain why I believe that shoaling fish are useful for analysing the underlying processes and mechanisms that lead to sexual segregation in animals. Lastly, I argue that it is unlikely that a single factor can explain social segregation or habitat segregation but that a model integrating different factors and different levels of segregation might succeed in describing proximate and ultimate causes of sexual segregation.
83714613
Out of the dark: Diurnal activity in the bat Hipposideros ruber on São Tomé island (West Africa)
Geographical areas historically characterized by a lower risk of diurnal avian predation should in theory allow bats to be active in daytime too, especially to forage. Oceanic islands are ideal for studying temporal niche shifts in bats since they often feature depauperate avian assemblages with fewer birds of prey. We report on the second case of diurnal activity known for an insular insectivorous bat, Hipposideros ruber on the island of Sao Tome (Gulf of Guinea). We present observations of daylight flights made at several sites on the island in six months (from July to November and in January). We also carried out daytime (09h00–16h00) emergence counts at three roosts. In this time interval, bats were continuously active, although activity rates changed: bats tended to return to roosts in early afternoon and, at two sites, to decrease emergence rate under intense light probably to reduce the risk of hyperthermia. At one roost, we observed that heavy rain caused abrupt daytime returns of large numbers of bats. In daytime bats did forage and kept echolocating. Social interactions (chases) were also frequently observed. In daytime adult males were significantly more frequent than females, while the opposite was noticed at night, an intersexual segregation possibly leading to temporal niche partitioning.
46114043
Sex and segregation in temperate bats
Many temperate insectivorous bats show marked sexual segregation during the summer, but in spectacular, pre-hibernation swarming, gather at caves to mate. In many species, sexual segregation is probably due to a gradient in aerial insect availability that confines females to lower elevations, where high reproductive costs are met by an abundant and reliable food supply. In the hawking and trawling Myotis daubentonii, we show that alongside inter-sexual segregation, there is intra-male segregation and suggest that this results from the exclusion of most males from high-quality habitat. These apparently excluded males suffer reduced foraging efficiency and mating success relative to males that roost with the females in summer. Changes in resources and behaviour at the end of the summer lead to a change in strategy that gives all males a chance to mate during swarming, but this does not overcome the paternity advantage to males that spend the summer with the females.
89190309
Spacing pattern, intersexual competition and niche segregation in American mink
Many animals, especially mustelids, show a spacing pattern known as intrasexual territoriality in which territorial animals defend areas against individuals of the same sex and there is extensive overlap between sexes. It has been argued that this overlap leads to sharing of food resources between territorial individuals of different sexes which has a net cost for territorial individuals. Several mechanisms have been proposed to reduce competition between sexes, many of them derived from sexual dimorphism, which is closely related to intrasexual territoriality. Among the suggested mechanism is spatial segregation between animals with overlapping areas, although it remains largely untested. We hypothesized that sexual spatial segregation in mustelids could be a consequence of a niche partition in habitat between sexes due to different optimums. We conducted a fine-grained radio tracking survey of seven feral American minks in winter. We compared home ranges, relative spatial positions and characteristics of radio-locations of different sexes. We also considered relative distances between simultaneous locations of overlapping individuals to test for dynamic territorial interactions. There were differences in the home range composition of males and females, and in their relative spatial location, proving spatial segregation between sexes. The comparison of locations showed that females preferred smaller streams as opposed to males that preferred large streams. In addition relative spatial position of female locations was independent of location of males in overlapping pairs, suggesting niche segregation caused by different sexual habitat preferences. Sexual habitat segregation is discussed as a powerful means of avoiding intersexual competition in species exhibiting intrasexual territoriality as a spacing pattern.
7459918
Selective aggressiveness in European free-tailed bats (Tadarida teniotis): influence of familiarity, age and sex
Bats are highly social mammals that often form large groups and represent good models to test the role played by individual status in shaping social relationships. Social cohesion relies on the ability of group and individual recognition, which is mediated by a range of sensorial cues. In this study, we selected the European free-tailed bat Tadarida teniotis as a model species to test the effects of familiarity, sex and age on aggressiveness and mutual tolerance. We hypothesize that T. teniotis is able to recognize group members and exhibit selective aggressiveness, and thus we predict fewer aggressive events and more amicable encounters between colony mates than between strangers. As female bats are generally more sociable and perform prolonged parental care to juveniles even after weaning, we hypothesize that sex and age of bats have significant influences on aggressive behaviours and thus predict that females will perform more amicable behaviours than males and that adults of both sexes will be less aggressive towards juveniles. Our results confirm that T. teniotis is able to discriminate between familiar and stranger individuals, showing higher rates of aggressive behaviours towards the latter. Females are more prone to exhibit amicable behaviours, particularly during same-sex interactions, while males show higher level of aggressiveness. Juveniles are subjected to fewer aggressive behaviours by adults of both sexes. Familiarity appears crucial for T. teniotis in determining the degree of aggressiveness during social interactions but the rate of aggressive events is also influenced by intrinsic individual factors such as sex and age.
80674392
Sexual segregation in vertebrates : ecology of the two sexes
Preface Part I. Overview: 1. Sexual segregation and the ecology of the two sexes Kathreen E. Ruckstuhl and Tim H. Clutton-Brock Part II. Concepts and Methodology: 2. Definitions, hypotheses, models and measures in the study of animal segregation Larissa Conradt Part III. Foraging Ecology: 3. Sex differences in the foraging ecology of large mammalian herbivores Johan T. du Toit 4. Sexual segregation in seals Ian J. Staniland 5. Sexual differences in foraging behaviour and diets: a case-study of wandering albatrosses Jose C. Xavier and John P. Croxall 6. Differences in foraging behaviour and feeding ecology in giant petrels Jacob Gonzales-Solis and John P. Croxall Part IV. Predator Avoidance and Reproductive Strategies: 7. Predation risk as a driving factor for size assortative shoaling and its implications for sexual segregation in fish Darren P. Croft, Jens Krause and Richard James 8. Differences in habitat selection and reproductive strategies of male and female sharks David W. Sims 9. Sex differences in reproductive strategies affect habitat choice in ungulates Martin B. Main and Johan T. du Toit Part V. Sex-related Activities and Social Factors: 10. Activity asynchrony and social segregation Kathreen E. Ruckstuhl and Peter Neuhaus 11. Sexual segregation in ungulates: from individual mechanisms to collective patterns Richard Bon, Jean-Louis Deneubourg, Jean-Francois Gerard and Pablo Michelena 12. Sexual segregation in humans Anthony D. Pellegrini, Jeffrey D. Long and Elizabeth A. Mizerek Part VI. Sexual Differences in Ecology: Comparisons within Different Taxa: 13. Ecological divergence between the sexes in reptiles Richard Shine and Mike Wall 14. Sexual segregation in Australian marsupials Abigail M. MacFarlane and Graeme Coulson 15. Social systems and ecology of bats John D. Altringham and Paula Senior 16. Sociality and ecology of the odontocetes Robert Michaud 17. Sexual segregation in non-human primates David P. Watts Part VII. Implications for Conservation: 18. Sexual segregation in birds: patterns, processes and implications for conservation Paulo Catry, Richard A. Phillips and John P. Croxal 19. Sexual segregation: a necessary consideration in wildlife conservation Esther S. Rubin and Vernon C. Bleich Part VIII. Outlook: 20. Conclusions and future directions Peter Neuhaus, Kathreen E. Ruckstuhl and Larissa Conradt References Index.
10364540
Sexual Segregation and Flexible Mating Patterns in Temperate Bats
Social structure evolves from a trade-off between the costs and benefits of group-living, which are in turn dependent upon the distribution of key resources such as food and shelter. Males and females, or juveniles and adults, may have different priorities when selecting habitat due to differences in physiological or behavioural imperatives, leading to complex patterns in group composition. We studied social structure and mating behaviour in the insectivorous bat Myotis daubentonii along an altitudinal gradient, combining field studies with molecular genetics. With increasing altitude the proportion of males in summer roosts increased and only males were present in the highest roosts. With increasing altitude environmental temperature decreased, nightly variation in temperature increased, and bat foraging activity decreased, supporting the hypothesis that the harsher, high elevation sites cannot support breeding females. We found that offspring in female-dominated lowland roosts had a very high probability of being fathered by bats caught during autumn swarming at hibernation sites, in contrast to those in intermediate roosts, which had a high probability of being fathered by males sharing the nursery roost with the females. Whilst females normally appear to exclude males from nursery colonies, for those in marginal habitats, one explanation for the presence of males is that the thermoregulatory benefits to the females may outweigh disadvantages, such as competition for food, and give some males an opportunity to increase their breeding success. We suggest that the environment, and its effects on resource distribution, thus determine social structure, which in turn determines the mating pattern that has evolved.
11783243
Altitudinal migration in bats: evidence, patterns, and drivers
Altitudinal migrations are common in all major vertebrate and some invertebrate lineages. Such migrations have important implications for the basic and applied ecology of animals making these movements. The idea that bats make altitudinal migrations has been suggested for nearly a century. However, studies documenting the existence and causes of altitudinal bat migrations are scarce, and are frequently published in the ‘grey’ literature. For the first time, we comprehensively review the evidence supporting the existence of altitudinal bat migrations worldwide, describe basic patterns of migration in temperate and tropical regions, and articulate and propose tests of hypotheses potentially explaining these migrations. We compiled a list of 50 studies indicative of altitudinal bat migration in 61 species (five families) from 21 countries (four continents). The temporal and spatial patterns of these migrations grouped biogeographically. Temperate bats generally exhibit sex‐biased migrations with females inhabiting lower elevations than males during reproductive periods. Although there is less information on tropical bat migration, few studies report sex‐biased migration. We compiled hypotheses proposed in the bat and (more extensive) avian literature to provide a list of hypotheses potentially explaining altitudinal bat migrations. These hypotheses rely upon temporal availability of (and competition for) food resources, spatial distribution of geomorphological features suitable for hibernation, sex‐related differences in the use of torpor, mating opportunities, and climatic factors that impose direct physiological challenges to survival or that restrict the ability to forage. A more thorough description of the migration patterns of most species will be required to distinguish effectively among these hypotheses. We identify research avenues that would broaden our understanding of bat migration patterns and provide critical information required for effective conservation.
84701568
Concentration of bat activity in riparian habitats over an elevational gradient
Riparian areas are generally assumed to represent important foraging areas for insectivorous bats, but this contention has rarely been formally quantified. To test this assumption, we used bat detectors to compare the relative activity levels of a community of temperate-zone bat species between riparian (lake) and upland (cutblock) habitats at three different elevations (ranging from 540 to 1800 m) in a forested area of southern British Columbia. In addition, we also investigated the sex and age class distributions of bats (based on mist-net captures) between riparian and upland habitats among the elevational zones. Bat activity levels were significantly greater in riparian than upland areas (10 and 40 times greater for foraging and commuting activity, respectively). Capture rates were greater in riparian areas and biased towards females, suggesting that female bats may preferentially select riparian areas, probably because of the abundant prey resources typically associated with this habitat. Captures of...
56139473
A comparison of bat activity at low and high elevations in the Black Hills of Western Washington
Erickson and Adams "A comparison of bat activity at low and high elevations in the Black Hills of Western Washington." Northwest Science. 2003; 77(2): 126-130
11075708
City life makes females fussy: sex differences in habitat use of temperate bats in urban areas
Urbanization is a major driver of the global loss of biodiversity; to mitigate its adverse effects, it is essential to understand what drives species' patterns of habitat use within the urban matrix. While many animal species are known to exhibit sex differences in habitat use, adaptability to the urban landscape is commonly examined at the species level, without consideration of intraspecific differences. The high energetic demands of pregnancy and lactation in female mammals can lead to sexual differences in habitat use, but little is known of how this might affect their response to urbanization. We predicted that female Pipistrellus pygmaeus would show greater selectivity of forging locations within urban woodland in comparison to males at both a local and landscape scale. In line with these predictions, we found there was a lower probability of finding females within woodlands which were poorly connected, highly cluttered, with a higher edge : interior ratio and fewer mature trees. By contrast, habitat quality and the composition of the surrounding landscape were less of a limiting factor in determining male distributions. These results indicate strong sexual differences in the habitat use of fragmented urban woodland, and this has important implications for our understanding of the adaptability of bats and mammals more generally to urbanization.
86750872
The diets of British bats (Chiroptera)
Sixty-one studies of the diets of 15 species of bats found in the British Isles are reviewed. Fourteen studies describe the diets of more than one species. Barbastella barbastellus and Plecotus spp. eat mainly Lepidoptera. Eptesicus serotinus takes mainly Coleoptera, but feeds on a wide range of prey, found in several habitats. Rhinolophus ferrumequinum hunts mainly Coleoptera and Lepidoptera by hawking, gleaning and perch hunting. Myotis bechsteinii takes mostly woodland families of Diptera and Lepidoptera. The remaining nine species eat mainly Diptera. Myotis nattereri feeds almost entirely on diurnal Diptera, gleaned from their nightly resting places. Rhinolophus hipposideros and Myotis mystacinus take mostly swarming crepuscular Diptera by hawking, probably near water and in damp wooded areas; both also glean. Myotis brandtii feeds on Diptera by hawking and gleaning; Nyctalus noctula by hawking. Myotis daubentonii, Pipistrellus spp. and Nyctalus leisleri eat many aquatic Diptera, and may therefore be expected to feed close to freshwater habitats. M. daubentonii hunts by trawling aquatic Diptera from the surface of water.
25293579
Next Generation Sequencing of Fecal DNA Reveals the Dietary Diversity of the Widespread Insectivorous Predator Daubenton’s Bat (Myotis daubentonii) in Southwestern Finland
Understanding predator-prey dynamics is a fundamental task in the evaluation of the adaptive capacities of species. However, direct observations or morphological identification of fecal remains do not offer an effective way to study the dietary ecology of elusive species, such as nocturnal insectivorous bats. However, recent advances in molecular techniques have opened a new method for identifying prey species from fecal samples. In this study, we amplified species-specific mitochondrial COI fragments from fecal DNA extractions from 34 individual Daubenton’s bats (Myotis daubentonii) collected between 2008 and 2010 from southwestern Finland. Altogether, 128 different species of prey were identified based on a comprehensive local DNA reference library. In our study area, Daubenton’s bats feed most frequently on insects of the orders Diptera (found in the diet of 94% individuals), Trichoptera (69%) and Lepidoptera (63%). The most frequent dipteran family in the diet was Chironomidae, which was found in 31 of 34 individuals. Most common prey species were chironomids Microtendipes pedellus (found in 50% of bats), Glyptotendipes cauliginellus (44%), and Procladius ferrugineus (41%). For the first time, an accurate species level list of the diet of the insectivorous Daubenton’s bat (Myotis daubentonii) in Finland is presented. We report a generally applicable method for describing the arthropod diet of vertebrate predators. We compare public databases to a national database to highlight the importance of a local reference database.
52854737
Mating at summer sites: indications from parentage analysis and roosting behaviour of Daubenton’s bats (Myotis daubentonii)
This study reports on evidence for successful mating of Myotis daubentonii at summer sites established by paternity analysis and behavioural observations. Parentage in individuals with high site fidelity was verified. Associations of parents in the same roosts before September and repeated fatherhood of a single resident male support the hypothesis of regular mating activities at summer sites. Based on the assumption that successful mating of many European bat species occurs at summer sites after the young are fledged, anthropogenic habitat changes should steer clear of the seasonal activity period to prevent a reduced reproduction rate of local bat populations.
85145728
Sex-related differences in roost-site selection by Daubenton's bats Myotis daubentonii during the nursery period
1 
We investigated sex-related differences in roost-site selection by Daubenton's bats Myotis daubentonii in their summer habitat in central Germany. We studied whether the location of and landscape structure around nine nursery roosts and seven male-only roosts differed during the nursery period (15 May−31 July). Roosts were located by radio-tracking, and animal numbers and group composition were obtained by trapping and counting at roosts. Landscape structure was evaluated by a GIS-based habitat analysis. 
 
2 
Marked variation in animal numbers was observed both in nursery roosts (range: 6–144 individuals) and male roosts (range: 1–51 individuals). The surroundings of nursery and male roosts varied significantly in the proportion of areas belonging to different landscape elements. The areas covered by ponds, lakes and rivers, as well as the area covered by coppices were larger in the surroundings of nursery roosts. Moreover, nursery roosts lay closer to a river and at lower altitudes than male roosts. Male Daubenton's bats used more distant foraging sites than gravid or lactating females. 
 
3 
The differences in roost-site location between the two sexes are suggestive of intraspecific competition for access to productive foraging areas in the surroundings of the summer roosts, with females being dominant over males. We assume that breeding females defend climatically favourable areas with good food supply in order to increase the survival of their offspring.
84050961
Ecological, Physiological, and Biochemical Aspects of Torpor in Mammals and Birds
As a physiological tactic to temporarily escape the brunt of cold and shortage of food and water, many mammals and birds have evolved the ability to exhibit torpor. Torpor in these heterothermic endotherms is characterized by a periodic, facultative lowering of the “thermostat” for body temperature regulation resulting in the achievement of a hypometabolic state for energy/water conservation. Depending on the species and ecological demand, the decrease of body temperature in torpor may range from 4° to 35°C and the period of torpor from a few hours to many weeks. Unlike torpor in the ectotherms, torpid endotherms are capable of spontaneously exiting from the depressed metabolic state using exclusively endogenously produced heat to restore euthermia (Fig. 1). This unique solution to a temporal energy/water crisis has been successfully employed by diverse groups of birds and mammals inhabiting the arctic, boreal and temperate regions where seasonal cold is predictable. Torpor has also been utilized by species inhabiting the deserts and semi-arid lands, where shortages of water and food may also manifest periodically. Somewhat surprisingly, however, torpor is also being deployed by those which inhabit the subtropical and tropical climates. In this case, daily, in addition to seasonal adversities may interfere with feeding and create a temporary energy shortage and the ability to exhibit torpor may prove to be advantageous. Extensive studies on the evolutionary, physiological and biochemical aspects have firmly established that torpor in birds and mammals is polyphyletic, and represents an advanced form of thermoregulation rather than a reversion to primitive poikilothermy (see Dawson and Hudson 1970; Hudson 1973; Lyman et al. 1982; Wang 1986, 1988; for reviews and references).
29999077
Natural Use of Heterothermy by a Small, Tree‐Roosting Bat during Summer
Little is known about the use of heterothermy by wild bats during summer, especially for tree‐roosting species. Because thermal conditions within tree roosts can fluctuate widely with ambient temperature, which affects thermoregulatory energy expenditure during diurnal roosting, we measured skin temperatures of free‐ranging male Nyctophilus geoffroyi (8 g) to quantify the relation between summer torpor use and roost thermal conditions. Bats roosted under bark on the northern (sunny) side of trees and entered torpor every day, usually near sunrise. Bats exhibited two bouts of torpor on most days: the first occurred in the morning, was terminated by partially passive rewarming, and was followed by a period of normothermy during the warmest part of the day; a second torpor bout occurred in the late afternoon, with arousal near sunset. On the warmest days, bats had only a single, short morning bout. On the coolest days, bats remained torpid throughout the day, and one 2‐d bout was observed. Thus, presumably owing to their poorly insulated roosts and the high energetic cost of normothermy at temperatures below 30°C, the extent and timing of heterothermy was closely related to the cycle of diurnal temperatures. Our study indicates that torpor use is important for energy maintenance during summer diurnal roosting of N. geoffroyi and likely of other small, tree‐roosting bats.
83825073
Patterns of daily torpor and day-roost selection by male and female big brown bats (Eptesicus fuscus)
Daily torpor can provide significant energy savings, but in bats may reduce rates of fetal and juvenile development and spermatogenesis. We examined the use of torpor during the day by male and female big brown bats (Eptesicus fuscus) in the field during the female gestation, lactation, and postlactation periods. While both sexes used torpor, males used it significantly more often and used deeper torpor than did reproductive females, indicating that the costs of torpor are higher for reproductive females. We suggest that by using shallow torpor, females may gain some of the benefits of torpor while minimizing the fitness costs. The different patterns of torpor may be responsible for observed differences in day-roost location amongst males, reproductive females, and nonreproductive females. Males should choose roosts with lower ambient temperatures than do females in order to increase the energy savings of torpor. Males and nonreproductive females roosted away from the maternity colonies more often than di...
27401073
Seasonal changes in daily torpor patterns of free-ranging female and male Daubenton’s bats (Myotis daubentonii)
Daily torpor can provide significant energy and water savings in bats during cold ambient temperatures and food scarcity. However, it may reduce rates of foetal and juvenile development. Therefore, reproductive females should optimize development by minimizing times in torpor. To test this hypothesis, the use of torpor by female and male free-ranging Daubenton’s bats (Myotis daubentonii) during reproduction (gestation, lactation, and post-lactation period) was investigated in 1998 and 1999. Temperature-sensitive radio transmitters were attached to the bats to measure skin temperature. Simultaneously, ambient temperature was recorded. While both sexes became torpid during daytime, male bats used daily torpor (>6°C below individual active temperature) significantly more often during reproductive period (mean: 78.4 % of day time in May and 43 % in June) than females. Female bats went into daily torpor, particularly in late summer when juveniles were weaned (mean: 66.6 % of daytime). Lowest skin temperatures occurred in a female bat with 21.0°C during post-lactation. Skin temperatures of male bats fluctuated from 16.8°C in torpor to 37.2°C during times of activity. There was a significant effect of reproductive period on skin temperature in females whereas mean ambient temperature had no significant effect. However, mean ambient temperature affected mean skin temperatures in males. Our findings indicate that female Daubenton’s bats adopt their thermoregulatory behaviour in particular to optimize the juvenile development.
2145646
Balancing the Energy Budget in Free-Ranging Male Myotis daubentonii Bats
Mammals use five main, mutually nonexclusive mechanisms to balance energy budgets: torpor, metabolic compensation, change in activity patterns, change in ingested energy, and/or variability in digestive efficiency. Bats, as small and actively flying mammals, have a high mass-specific energy demand; therefore, balancing mechanisms should be pronounced in this group. We found that male Myotis daubentonii exhibited marked variation in the relative importance of these different mechanisms during their period of seasonal activity in response to extrinsic (ambient temperature, insect abundance) and intrinsic (reproduction, body condition) factors. Cold ambient temperatures in spring facilitated long and frequent daily torpor bouts, whereas in early summer, increased energy intake was the dominant factor in energy balancing. Intake was further increased in late summer, when insect abundance was highest, and daily torpor bouts were shorter and less frequent than in early summer. In autumn, males used metabolic compensation to reduce their resting metabolic rate in addition to daily torpor. Metabolic compensation might be one of the mechanisms that allow males to maintain high body temperature during the day while decreasing the need for foraging time at night, thus maximizing their opportunities to mate.
90230054
Thermoregulation of tree-dwelling temperate bats — a behavioural adaptation to force live history strategy
Abstract. Metabolic rate and body temperature (Tb) reduction during torpor can provide significant energy savings for bats during inclement weather and food scarcity. However, torpor use may slow down biochemical processes including fetal and juvenile development and sperm production. Sex-differences in the timing of reproductive activity of bats in the temperate climate zone should result in differences of the thermoregulation behaviour by males and females during summer. To test this hypothesis, we studied thermoregulation of free-ranging, tree-dwelling gleaning bats (Myotis bechsteinii) and trawling bats (M. daubentonii) during different reproductive periods. Gleaners and trawlers are able to forage on prey which is sitting on vegetation and the ground (gleaning) or which is slowly moving over water bodies (trawling). This prey is characterized by lower ambient temperature (Ta) dependent abundance than flying prey. We used temperature-sensitive radio transmitters to measure skin temperature (Tsk). Temperature telemetry over 144 census days revealed a significant effect of reproductive period and sex on Tsk. Pre-spermatogenic males exhibited a significantly greater Tsk reduction than females in early pregnancy. Males at the beginning of sperm production and in main spermatogenesis exhibited much more frequent and deeper temperature reductions than females in late pregnancy and in lactation. Lactating females maintained the highest Tsk of all bats. Post-lactating females reduced Tsk to the same extent or even more than males in advanced spermatogenesis. Our findings indicate that the thermoregulation of gleaning and trawling temperate bats is likely to be much less influenced by environmental conditions than that of aerial hawking bat species. We suggest that both sexes of Bechstein's bats and Daubenton's bats primarily adapt their thermoregulation in response to current reproductive activity.
16438063
Spatiotemporal pattern of local sexual segregation in a tree-dwelling temperate bat Myotis daubentonii
Sexual segregation is a common phenomenon in temperate bats, but little is known about driving forces or spatiotemporal patterns. Sexual segregation of the tree-dwelling Daubenton’s bat (Myotis daubentonii) was analyzed. Day roosts and foraging areas of radio-tracked animals were recorded during late spring, early summer, and late summer. Home ranges were calculated for each sex based on identified locations. Distance analysis between sex-specific roosts and foraging areas was conducted for each period. Mixed colonies were confirmed by trapping at roosts. Home range of males was larger (47.3 km2) than of females (9.7 km2). During late spring, distances between male and female roosts were larger (median = 715 m) than during early (median = 474 m) and late summer (median = 489 m). Distances between sex-specific foraging areas were larger during early summer (median = 2,134 m) than during both late spring (median = 1,116 m) and late summer (median = 628 m). The proportion of males in mixed groups increased from late spring (0.2 ± 0.1) to late summer (0.5 ± 0.2). These results show that sexual segregation is not static, but depends on energetic demand of individuals and mating willingness. A high energetic demand in females and low mating willingness in both sexes leads to distinct sexual segregation during late spring. When mating willingness increases, despite an increasing energy demand in males, sexes aggregate to mate.
21732316
Thermal energetics of female big brown bats (Eptesicus fuscus)
We investigated thermoregulation and energetics in female big brown bats, Eptesicus fuscus (Beauvois, 1796). We exposed bats to a range of ambient temperatures (Ta) and used open-flow respirometry to record their metabolic re- sponses. The bats were typically thermoconforming and almost always entered torpor at Tas below the lower critical temperature Tlc of 26.7 °C. Basal metabolic rate (BMR, 16.98 ± 2.04 mL O2·h -1 , mean body mass = 15.0 ± 1.4 g) and torpid metabolic rate (TMR, 0.460 ± 0.207 mL O2·h -1 , mean body mass = 14.7 ± 1.3 g) were similar to values re- ported for other vespertilionid bats of similar size and similar to a value for E. fuscus BMR calculated from data in a previous paper. However, we found that big brown bats had a lower Tlc and lower thermal conductance at low Ta rela- tive to those measured in the previous study. During torpor, the minimum individual body temperature (Tb) that we re- corded was 1.1 °C and the bats began defending minimum Tb at Ta of approximately 0 °C. BMR of big brown bats was 76% of that predicted for bats based on the relationship between BMR and body mass. However, the Vespert- ilionidae have been under-represented in previous analyses of the relationship between BMR and body mass in bats. Our data, combined with data for other vespertilionids, suggest that the family may be characterized by a lower BMR than that predicted based on data from other groups of bats.
7787300
Deep, prolonged torpor by pregnant, free-ranging bats
Many mammals save energy during food shortage or harsh weather using controlled reductions in body temperature and metabolism called torpor. However, torpor slows offspring growth, and reproductive individuals are thought to avoid using it because of reduced fitness resulting from delayed offspring development. We tested this hypothesis by investigating torpor during reproduction in hoary bats (Lasiurus cinereus, Vespertilionidae) in southern Canada. We recorded deep, prolonged torpor bouts, which meet the definition for hibernation, by pregnant females. Prolonged torpor occurred during spring storms. When conditions improved females aroused and gave birth within several days. Our observations imply a fitness advantage of torpor in addition to energy conservation because reduced foetal growth rate could delay parturition until conditions are more favourable for lactation and neonatal survival.
7674256
Defining torpor in free-ranging bats: experimental evaluation of external temperature-sensitive radiotransmitters and the concept of active temperature
A variety of definitions involving body temperature (Tb), metabolic rate and behavior have been used to define torpor in mammals and birds. This problem is confounded in some studies of free-ranging animals that employ only skin temperature (Tsk), a measure that approximates but may not precisely reflect Tb. We assess the accuracy of Tsk in the context of a recent definition for torpor called active temperature. We compared the active temperatures of individual big brown bats (Eptesicus fuscus), which aggregate in cavities, with solitary, foliage-roosting hoary bats (Lasiurus cinereus). In captive big brown bats, we compared Tsk and core Tb at a range of ambient temperatures for clustered and solitary roosting animals, compared Tsk and Tb during arousal from torpor, and quantified the effect of flight on warming from torpor. Hoary bats had significantly lower active temperatures than big brown bats despite having the same normothermic Tsk. Tsk was significantly lower than Tb during normothermia but often greater than Tb during torpor. Flight increased the rate of warming from torpor. This effect was more pronounced for Tsk than Tb. This suggests that bats could rely on heat generated by flight muscles to complete the final stages of arousal. Using active temperature to define torpor may underestimate torpor due to ambient cooling of external transmitters or animals leaving roosts while still torpid. Conversely, active temperature may also overestimate shallow torpor use if it is recorded during active arousal when shivering and non-shivering thermogenesis warm external transmitters. Our findings illuminate the need for laboratory studies that quantify the relationship between metabolic rate and Tsk over a range of ambient temperatures.
18541676
A New Comparative Metric for Estimating Heterothermy in Endotherms
A major focus in the study of endothermic thermoregulation has been the description of thermoregulatory patterns used by various species and/or populations. Compared with ectotherms, relatively few attempts have been made to study the thermoregulation of endotherms in an adaptive framework. We believe that one of the main factors limiting this area of research has been the lack of an appropriate metric to directly compare body temperature (Tb) variation across all endothermic species. Thus, we present a simple comparative metric, the heterothermy index (HI), to quantify the expression of heterothermy by endotherms during a given time frame. Key advantages of HI are that (1) it represents a new analytical technique that has different strengths than the metrics commonly used to describe variation in Tb, (2) it allows for evaluation of nonenergetic costs and benefits that affect the expression of heterothermy, and (3) it has the potential to unify research on homeotherms and heterotherms through quantitative comparative analyses that examine the entire continuum of thermoregulatory patterns. In short, we suggest that our metric provides a means to overcome one of the hurdles presently slowing the advancement of research on endothermic thermoregulation beyond the simple description of thermoregulatory patterns.
8849104
New perspectives for estimating body condition from mass/length data: the scaled mass index as an alternative method
Body condition is assumed to influence an animal’s health and fitness. Various non-destructive methods based on body mass and a measure of body length have been used as condition indices (CIs), but the dominant method amongst ecologists is currently the calculation of residuals from an ordinary least squares (OLS) regression of body mass against length. Recent studies of energy reserves in small mammals and starlings claimed to validate this method, although we argue that they did not include the most appropriate tests since they compared the CI with the absolute size of energy reserves. We present a novel CI (the ‘scaled mass index’) based on the central principle of scaling, with important methodological, biological and conceptual advantages. Through a reanalysis of data from small mammals, starlings and snakes, we show that the scaled mass index is a better indicator of the relative size of energy reserves and other body components than OLS residuals, performing better in all seven species and in 19 out of 20 analyses. We also present an empirical and theoretical comparison of the scaled mass index and OLS residuals as CIs. We argue that the scaled mass index is a useful new tool for ecologists.
887335
Female Mate Choice Can Drive the Evolution of High Frequency Echolocation in Bats: A Case Study with Rhinolophus mehelyi
Animals employ an array of signals (i.e. visual, acoustic, olfactory) for communication. Natural selection favours signals, receptors, and signalling behaviour that optimise the received signal relative to background noise. When the signal is used for more than one function, antagonisms amongst the different signalling functions may constrain the optimisation of the signal for any one function. Sexual selection through mate choice can strongly modify the effects of natural selection on signalling systems ultimately causing maladaptive signals to evolve. Echolocating bats represent a fascinating group in which to study the evolution of signalling systems as unlike bird songs or frog calls, echolocation has a dual role in foraging and communication. The function of bat echolocation is to generate echoes that the calling bat uses for orientation and food detection with call characteristics being directly related to the exploitation of particular ecological niches. Therefore, it is commonly assumed that echolocation has been shaped by ecology via natural selection. Here we demonstrate for the first time using a novel combined behavioural, ecological and genetic approach that in a bat species, Rhinolophus mehelyi: (1) echolocation peak frequency is an honest signal of body size; (2) females preferentially select males with high frequency calls during the mating season; (3) high frequency males sire more off-spring, providing evidence that echolocation calls may play a role in female mate choice. Our data refute the sole role of ecology in the evolution of echolocation and highlight the antagonistic interplay between natural and sexual selection in shaping acoustic signals.
55468573
The paradigm of body condition: a critical reappraisal of current methods based on mass and length
Summary 
 
1. Body condition is a major concept in ecology addressed in countless studies, and a variety of non-destructive methods are used to estimate the condition of individuals based on the relationship between body mass M and measures of length L. There is currently no consensus about the most appropriate condition index (CI) method, and various traditions have been established within subdisciplines in which ecologists tend to apply that method used previously by their peers. 
 
 
 
2. Here, we present a reappraisal of six conventional CI methods: Fulton’s index (K = M/L3), Quetelet’s index (BMI = M/L2), Relative condition (Kn, computed as the observed individual mass divided by the predicted mass Mi* = a Lib where a and b are determined by ordinary least squares (OLS) regression of M against L), Relative mass (Wr, where a and b above are determined from a reference population), the Residual index (Ri, the residuals from an OLS regression of M against L) and ancova. We compare the performance of these methods with that of the Scaled mass index, a novel method which was previously shown to perform better than Ri as a predictor of fat and other body components [J. Peig & A.J. Green (2009) Oikos, 118, 1883]. 
 
 
 
3. To be reliable, a CI method must successfully account for the changing relationship between M and L as body size changes and growth occurs (i.e. for the scaling relationship between M and L). Using data from three species of small mammals we show that, unlike the Scaled mass index, all six conventional methods fail to do this, and as a result they consistently lead to significant differences in CIs between age classes and sex that are a mere consequence of changes in body size. The Scaled mass index was also particularly successful at detecting changes in CI resulting from high levels of contaminants.
122001970
Analysis of Wildlife Radio-Tracking Data
Preliminaries. Design of Radio-Tracking Studies. Effects of Tagging on the Animal. Estimating Animal Locations. Designing and Testing Triangulation Systems. Simple Movements. Home Range Estimation. Habitat Analysis. Survival Rate Estimation. Population Estimation. Data Analysis System. Appendices. Each chapter includes references. Index.
85040463
Compositional Analysis of Habitat Use From Animal Radio-Tracking Data
Analysis of habitat use based on radio-tagged animals presents difficulties inadequately addressed by current methods. Areas of concern are sampling level, data pooling across individuals, non-independence of habitat proportions, differential habitat use by groups of animals, and arbitrary definition of habitat availability. We advocate proportional habitat use by individual animals as a basis for analysis. Hypothesis testing of such nonstandard multivariate data is done by compositional analysis, which encom- passes all MANOVA/MANCOVA-type linear models. The applications to habitat use range from testing for age class effects or seasonal differences, to examining relationships with food abundance or home range size. We take as an example the comparison of habitat use and availability. The concepts are explained and demonstrated on two data sets, illustrating different methods of treating missing values. We compare utilized with available habitats in two stages, examining home range selection within the overall study area first, then habitat use within the home range. At each stage, assuming that use differs from random, habitats can be ranked according to relative use, and significant between-rank differences located. Compositional analysis is also suited to the analysis of time budgets or diets.
84802543
K-select analysis: a new method to analyse habitat selection in radio-tracking studies
Two kinds of wildlife habitat studies can be distinguished in the literature: hindcasting and forecasting studies. Hindcasting studies aim to emphasize among a large set of habitat variables those that are of interest for the focus species, whereas forecasting studies are intended to predict habitat selection according to a small number of habitat variables for a given area. We provide here a new analytical tool which relies on the concept of ecological niche, the K-select analysis, for hindcasting studies of habitat selection by animals using radio-tracking data. Each habitat variable defines one dimension in the ecological space. For each animal, the difference between the vector of average available habitat conditions and the vector of average used conditions defines the marginality vector. Its size is proportional to the importance of habitat selection, and its direction indicates which variables are selected. By performing a non-centered principal component analysis of the table containing the coordinates of the marginality vectors of each animal (row) on the habitat variables (column), the K-select analysis returns a linear combination of habitat variables for which the average marginality is greatest. It is a synthesis of variables which contributes the most to the habitat selection. As with principal component analysis, the biological significance of the factorial axes is deduced from the loading of variables. An example is provided: habitat selection by wild boar is studied in a Mediterranean habitat using the K-select analysis. The numerous advantages of the analysis (a large number of variables that can be included, individual variability in habitat selection taken into account, a lack of too strict underlying hypotheses) make it a powerful approach in radio-tracking studies designed to identify habitat variables that are selected by animals.
126440622
Chironomid Midges as Indicators of Organic Pollution in the Scioto River Basin, Ohio
Faunal and water chemistry data were derived from an extensive survey of streams in the Scioto River basin, Ohio and analyzed to determine biotic indicators of water quality. The data for 11 water chemistry characteristics were simplified by means of factor analysis, which generated three new axes (alkalinity-hardness, enrichment (sewage), agricultural runoff) that explained 71.5% of the total variance. The distributions of 14 common larval chironomid genera were then placed upon these new axes, based on coordinates generated for each sample site. These genera were found to occupy significantly different environments. Heuristic analysis of the data identified five groups of genera, each indicating particular water quality conditions: 1) Stictocbironomus—hard, alkaline unpolluted water; 2) Pentaneura, Cricotopus, and Tanytarsus—sewage enriched water; 3) Procladius and Dicrotendipes—high agricultural runoff; 4) Ablabesmyia and Tribelos —general organic pollution, soft acid water; and 5) Micropsectra, Microtendipes, Glyptotendipes, Chironomus, Polypedilum, and Cryptochironomus — facultative genera. OHIO J. SCI. 89 (1): 5-9, 1989
129655885
Midges and palaeotemperature reconstruction—the North American experience
Abstract The development of midge-based palaeoclimatology in North America is reviewed, with a focus on Lateglacial and Holocene climatic change. Although relatively few sites have been studied, midge-inferred palaeotemperatures reveal detailed records of Lateglacial climate oscillations and more subtle Holocene temperature changes. Holocene climate changes are often at, or near, the detection limit using current palaeotemperature inference models. Interference from other environmental variables, including water depth and oxygen concentration changes are discussed, as well as the challenges inherent to developing better models. The isotopic signature of chitin preserved in midge head capsules has opened new avenues for midge–palaeotemperature inference. Through coordinated research efforts, national and international collaborations will provide opportunities to reconstruct Holocene palaeoclimate at continental and hemispheric scales.
55233276
Bat conservation and large dams: spatial changes in habitat use caused by Europe's largest reservoir
Large dams have had a major impact on a number of botanical and faunal groups. Nevertheless, little is known about their effect on bat populations. As part of a multipurpose project, the Alqueva dam was constructed during 2001 in Alentejo (Southern Portugal) and has created the largest reservoir in Europe. Its construction caused major changes in the region, mainly due to the deforestation and submersion of an area of 250 km 2 . A 2-stage survey was implemented in order to evaluate the impact of these landscape changes on bat populations present in the region, as well as to define minimization and compensation measures. Bat activity was surveyed prior to and after the deforestation and flooding of the area, mainly through the use of ultra-sound detectors. The results show a clear decline in bat activity over the area now submerged; islands within the reservoir seem to be the only remaining foraging areas. Furthermore, bat activity increased in the area surrounding the reservoir. In this area, bats used similar foraging habitat types during both stages of the survey, confirming the importance of riparian habitats as foraging areas. Bat populations of this region were thus affected simultaneously by the disappearance of around 200 km of riparian habitat, extensive loss of roosts and the creation of a vast homogeneous habitat that is rarely used for foraging. In pro- jects of this dimension, the future of bat communities is clearly dependent on the preservation of roosts and the most important habitats surrounding the reservoir.
85417963
Thermoregulation in male temperate bats depends on habitat characteristics
Several energy-saving strategies have evolved in animals, one example being the short-term reduction of metabolism and body temperature (torpor) in endotherms. For bats, pronounced torpor behaviour has been described. The aim of this study was to assess individual variation in torpor expression of male Myotis daubentonii, and to analyse whether this variation is related to habitat characteristics. For that we measured skin temperatures of bats from different habitats using radio transmitters and also recorded ambient temperature. Skin temperature was corrected for ambient temperature and individual body mass. Cluster analysis of residuals revealed two different thermoregulatory strategies. Males in cluster 1 were more often encountered torpid and reached lower minimum skin temperatures than males in cluster 2. The differences in behaviour were related to environmental variables (water surface area near the roost, roost altitude, precipitation, ambient temperature in the warmest quarter of the year). Males from cluster 1 occupied less favourable habitats (less water surface, higher altitudes, wetter and colder climate) than males from cluster 2. Our data suggest a linkage between torpor behaviour and habitat characteristics. These characteristics could be used to identify favourable and marginal habitats for M. daubentonii.
18883952
Thermal physiology of pregnant and lactating female and male long-eared bats, Nyctophilus geoffroyi and N. gouldi
During roosting in summer, reproductive female bats appear to use torpor less frequently and at higher body temperatures (Tb) than male bats, ostensibly to maximise offspring growth. To test whether field observations result from differences in thermal physiology or behavioural thermoregulation during roosting, we measured the thermoregulatory response and energetics of captive pregnant and lactating female and male long-eared bats (Nyctophilus geoffroyi 8.9 g and N. gouldi 11.5 g) during overnight exposure to a constant ambient temperature (Ta) of 15°C. Bats were captured 1–1.5 h after sunset and measurements began at 21:22±0:36 h. All N. geoffroyi entered torpor commencing at 23:47±01:01 h. For N. gouldi, 10/10 males, 9/10 pregnant females and 7/8 lactating females entered torpor commencing at 01:10±01:40 h. The minimum Tb of torpid bats was 15.6±1.1°C and torpid metabolic rate (TMR) was reduced to 0.05±0.02 ml O2 g−1 h−1. Sex or reproductive condition of either species did not affect the timing of entry into torpor (F=1.5, df=2, 19, P=0.24), minimum TMR (F=0.21, df=4, 40, P=0.93) or minimum Tb (F=0.76, df=5, 41, P=0.58). Moreover, sex or reproductive condition did not affect the allometric relationship between minimum resting metabolic rate and body mass (F=1.1, df=4, 37, P=0.37). Our study shows that under identical thermal conditions, thermal physiology of pregnant and lactating female and male bats are indistinguishable. This suggests that the observed reluctance by reproductive females to enter torpor in the field is predominantly because of ecological rather than physiological differences, which reflect the fact that females roost gregariously whereas male bats typically roost solitarily.
86396103
Winter activity of a population of greater horseshoe bats, Rhinolophus ferrumequinum
Activity patterns of greater horseshoe bats Rhinolophus ferrumequinum were investigated at caves in Cheddar (south-west England) during the hibernation season. An ultrasound detector and datalogger were used to monitor and record the number of echolocation calls in a single cave. Activity of R. ferrumequinum remained largely nocturnal throughout winter, and the mean time of activity over 24 h was 88 to 369 min after sunset. There was an increase in diurnal activity from late May to early June, probably because bats remained active after foraging at dawn towards the end of the hibernation season. Visits to the cave did not increase bat activity. Cave air temperature reflected external climatic temperature, although there was variation in cave temperature and its range within and among caves. Individual R. ferrumequinum are usually dispersed in caves in regions where temperature fluctuations correlate with climatic variations in temperature. There was a positive correlation between the number of daily bat passes monitored by the bat detector and datalogger (= daily activity) and cave temperature. Nocturnal activity may be sometimes associated with winter feeding. Neither date nor barometric pressure had a significant effect on daily activity. Activity patterns largely reflected the findings from individual R. ferrumequinum studied by telemetry (Park, 1998), in that bat activity increased with cave and climatic temperatures, and the temporal pattern of activity remained consistently nocturnal throughout winter, starting at dusk.
86237340
Torpor, arousal and activity of hibernating Greater Horseshoe Bats (Rhinolophus ferrumequinum)
1. Patterns of torpor, arousal and activity in free-living Greater Horseshoe Bats, Rhinolophus ferrumequinum (Schreber), were investigated during the hibernation period by using temperature-sensitive radio-transmitters. 
 
2. Torpor bouts varied between 0·1 and 11·8 days, with individual means ranging from 1·3 to 7·4 days. Torpor bout duration decreased with increasing ambient temperature. 
 
3. Activity duration varied from 37 min to 54 h 24 min, with individual means ranging from 2 : 29 to 8 : 58 h. Activity duration increased with ambient temperatures above approximately 10 °C. 
 
4. Ten of 11 bats synchronized their arousals with dusk. The circadian rhythm of one bat showed a free-running pattern over a period of about 5 weeks. Arousals were more highly synchronized, and closer to dusk, in individuals with lower body condition. 
 
5. That bats forage in mild weather is supported by the strong synchronization of arousals with dusk, especially in bats with low body condition. 
 
6. Patterns of torpor and subsequent activity are consistent with predictions that torpor lasts until a critical metabolic or water imbalance is achieved. Because metabolism and water loss are temperature-dependent, torpor bout duration decreases with increasing temperature. The imbalance is corrected during subsequent activity, which is relatively constant in duration until a temperature threshold of 10 °C, above which increasing levels of foraging lead to longer activity bouts.
84988697
Winter foraging activity of Central European Vespertilionid bats
Abstract The winter activity of bats was studied in an area of Bavaria, Southern Germany, for seven consecutive years (2007–2013). Echolocation calls were recorded in known foraging areas between October and March of each winter, and bats were regularly seen on evenings with temperatures above +6 °C, except for the period between mid-December and mid-February, when even bouts of warm weather did not appear to trigger foraging activity. Below +3 °C no bats appeared in the foraging areas. The most frequently recorded species were Nyctalus noctula, Pipistrellus pipistrellus, Pipistrellus nathusii and Vespertilio murinus. Final buzzes indicating attempts to catch prey were recorded for these species even in December and February, which supports the idea that the bats were not only in search of water or just moving between roosts. Myotis species, on the other hand, which hibernate in roosts offering more constant temperature conditions, were not observed at all between mid-November and March. Further investigations have to show whether warmer winter evenings offer bats an opportunity for casual hunting or whether winter foraging expresses an urgent need for weak individuals.
84496813
Echolocation constraints of Daubenton’s Bat foraging over water
Summary 1. Daubenton’s Bats ( Myotis daubentonii) foraging over a stream concentrated their activity over calm surfaces, avoiding an adjacent area with small ripples (< 3 cm high). Aerial insects were most abundant over the ripples, so insect distribution could not explain why the bats avoided this area. 2. The bats flew low over water and always ( N = 22) directed the head forwards, presumably emitting the echolocation beam parallel to the surface, thus minimizing clutter. At an angle of incidence of 30° there was significantly more clutter from the rippled water. 3. The ripples produced ultrasonic noises in the form of transient pulses at an average rate of 6·2 per second. In the present case, such pulses were common enough potentially to interfere with target detection by the bats. Transient noises and echo clutter from moving ripples may be the principal reason why bats generally avoid foraging low over turbulent water. 4. The target strength of a potential insect prey at the water surface and the source levels of the bats’ searching signals were measured to use in estimating the echo level at the bat when it detects the prey. The echo level at detection (+ 38 dB sound pressure level) was about the same as the clutter level extrapolated to the detection distance. This suggests that Daubenton’s Bat operates at very low signal-to-noise ratios when foraging for insects near the water surface.
84660882
Use of foraging habitats by bats in a Mediterranean area determined by acoustic surveys: conservation implications
We determined habitat use by foraging bats by broad-band acoustic surveys in 10 habitat types from a Mediterranean area (southern Italy). We applied discriminant functions to identify time-expanded echolocation calls from free-flying bats. 
 
Moon phase and cloud cover had no effect on bat activity. Only Hypsugo savii was influenced by temperature, and activity of Myotis daubentonii and Myotis capaccinii was reduced at higher wind speeds. Both total numbers of bat passes and feeding buzzes were highest over rivers and lakes. Pipistrellus kuhlii and H. savii were most frequently recorded. Pipistrellus kuhlii, Pipistrellus pipistrellus and Tadarida teniotis proved generalists in using foraging habitats. 
 
Water sites and conifer plantations were respectively the most and the least used habitats by H. savii. Rivers were especially important to Myotis bats, Miniopterus schreibersii and Pipistrellus pygmaeus. Unlike P. kuhlii, P. pipistrellus was frequent in beech woodlands; P. pygmaeus made a considerable use of chestnut woodlands and Myotis spp. were moderately active in both these woodland types. 
 
A large number of endangered or vulnerable species featured in riparian habitats, broadleaved woodlands and olive groves. Riparian and woodland habitats constitute an important target for conservation. Typical land use forms such as woodlands used for chestnut production and traditionally managed olive groves should be encouraged in conservation plans. The negative impact of urbanisation on bats might be counteracted by fostering trees, gardens and small cultivated patches. Farmland practices should encourage landscape complexity and limit the use of pesticides.
83878305
The effect of familiarity on echolocation in the megachiropteran bat Rousettus aegyptiacus
Much is known about the way bats adjust their echolocation behaviour in response to environmental structure or to locate insect prey. By contrast, little is known about how echolocation calls are modulated in response to familiarity of the environment and objects within it. Here we show that the echolocating Megachiropteran bat Rousettus aegyptiacus produces echolocation signals at the same rate whether an obstacle is predictable or unpredictable in location, but that it has a reduced rate of echolocation signal production in a familiar environment with no obstacle present. This suggests that signal production is reduced in a familiar environment absent of 'clutter' but that probing the environment for maximum information is more important for this species than minimizing any cost of probing the environment in a cluttered space.
15186151
Sensory Ecology of Water Detection by Bats: A Field Experiment
Bats face a great risk of dehydration, so sensory mechanisms for water recognition are crucial for their survival. In the laboratory, bats recognized any smooth horizontal surface as water because these provide analogous reflections of echolocation calls. We tested whether bats also approach smooth horizontal surfaces other than water to drink in nature by partly covering watering troughs used by hundreds of bats with a Perspex layer mimicking water. We aimed 1) to confirm that under natural conditions too bats mistake any horizontal smooth surface for water by testing this on large numbers of individuals from a range of species and 2) to assess the occurrence of learning effects. Eleven bat species mistook Perspex for water relying chiefly on echoacoustic information. Using black instead of transparent Perspex did not deter bats from attempting to drink. In Barbastella barbastellus no echolocation differences occurred between bats approaching the water and the Perspex surfaces respectively, confirming that bats perceive water and Perspex to be acoustically similar. The drinking attempt rates at the fake surface were often lower than those recorded in the laboratory: bats then either left the site or moved to the control water surface. This suggests that bats modified their behaviour as soon as the lack of drinking reward had overridden the influence of echoacoustic information. Regardless of which of two adjoining surfaces was covered, bats preferentially approached and attempted to drink from the first surface encountered, probably because they followed a common route, involving spatial memory and perhaps social coordination. Overall, although acoustic recognition itself is stereotyped and its importance in the drinking process overwhelming, our findings point at the role of experience in increasing behavioural flexibility under natural conditions.
84189173
Dispersal of adult aquatic Chironomidae (Diptera) in agricultural landscapes
SUMMARY 
 
1 
This study investigates the possible influence of terrestrial landscape structure on the spatial distribution of adult Chironomidae emerging from water bodies in three agricultural areas, each with hedgerow networks, in Brittany (France). 
 
2 
Using spatially explicit data from 128 yellow pan traps set in pairs at the bottom of hedges throughout the three study areas, we show that landscape structure and heterogeneity must be considered at two different spatial scales. 
 
3 
At a global scale, distance to water bodies was the main factor explaining the spatial distribution of adult chironomids: both species richness and abundance changed beyond a critical distance to the stream, resulting in different species assemblages of flying insects. 
 
4 
At a local scale, the abundance of species and individuals at rest in hedges changed with the quality of the hedge (mainly determined by canopy width and cover of the different vegetation layers). 
 
5 
The density of the hedgerow network, and landscape openness, both influenced the dispersal of chironomid species from water bodies. 
 
6 
This study, which provides the first estimate of the dispersal capabilities of chironomids in particular landscapes, suggests that the terrestrial environment is an essential component of population dynamics and community structure in aquatic Chironomidae.
85921982
Habitat selection and spatial use by the trawling bat Myotis capaccinii (Bonaparte, 1837)
ABSTRACT Habitat selection and spatial use was studied in a population of Myotis capaccinii (Bonaparte, 1837) in the eastern Iberian Peninsula during the spring of 2004. The radio-tracked bats used only aquatic habitats as foraging sites, and most foraging activity concentrated on rivers. Rivers were positively selected and showed the highest preference rank. Pools were also positively selected but only a single pool was used through the tracking period. Foraging was not evenly distributed along rivers. The features of the water surface further determined habitat selection. Open waters with smooth surfaces were selected over cluttered surfaces or waters completely covered by vegetation. This microhabitat preference is thought to be due to a greater efficiency in prey detection and capture over open calm waters. Nonetheless, the extremely high aggregation of foraging individuals observed suggests that the distribution of prey might also affect the location of foraging sites along rivers. Thus, conservation management of M. capaccinii should ensure protection of low-flowing or stagnant waters in rivers around the bats' main caves.
55080360
Foraging behaviour of the long-fingered bat Myotis capaccinii: implications for conservation and management
The main factors threatening Myotis capaccinii (Bonaparte, 1837) are considered to be foraging habitat degradation and roost loss. Conservation strategies that focus on the protection of roosts are feasible as long as direct threats by human activities are correctly identified. However, before protection of foraging habitat can be implemented more accurate information is required. We review the available information of relevance to foraging habitat management for the species. Three main topics are considered based on the results of a radiotelemetry study on 45 ind. in 3 seasons: habitat dependence, features of foraging habitat, and spatial range. M. capaccinii foraged almost completely over aquatic habitats as in other telemetry studies. We discuss the importance of terres- trial habitats and the dependence of the species on aquatic habitats. It has been proposed that sev- eral factors affect habitat selection in this species. The presence of smooth, clutter-free water surfaces seems to be the most important structural factor, but we found that prey richness also affected habi- tat selection. Effects of features related to riparian vegetation and water quality are thought to vary according to local conditions. Preference for wide water bodies is probably linked to preference for smooth surfaces, where detection and trawling of prey is favoured. As highlighted by recent teleme- try studies, we observed M. capaccinii foraging at long distances from the roost. Therefore, the area of application for conservation measures should be large: we suggest a protection radius of 20 km around roosts.
16126476
Sympatric Woodland Myotis Bats Form Tight-Knit Social Groups with Exclusive Roost Home Ranges
Background The structuring of wild animal populations can influence population dynamics, disease spread, and information transfer. Social network analysis potentially offers insights into these processes but is rarely, if ever, used to investigate more than one species in a community. We therefore compared the social, temporal and spatial networks of sympatric Myotis bats (M. nattereri (Natterer's bats) and M. daubentonii (Daubenton's bats)), and asked: (1) are there long-lasting social associations within species? (2) do the ranges occupied by roosting social groups overlap within or between species? (3) are M. daubentonii bachelor colonies excluded from roosting in areas used by maternity groups? Results Using data on 490 ringed M. nattereri and 978 M. daubentonii from 379 colonies, we found that both species formed stable social groups encompassing multiple colonies. M. nattereri formed 11 mixed-sex social groups with few (4.3%) inter-group associations. Approximately half of all M. nattereri were associated with the same individuals when recaptured, with many associations being long-term (>100 days). In contrast, M. daubentonii were sexually segregated; only a quarter of pairs were associated at recapture after a few days, and inter-sex associations were not long-lasting. Social groups of M. nattereri and female M. daubentonii had small roost home ranges (mean 0.2 km2 in each case). Intra-specific overlap was low, but inter-specific overlap was high, suggesting territoriality within but not between species. M. daubentonii bachelor colonies did not appear to be excluded from roosting areas used by females. Conclusions Our data suggest marked species- and sex-specific patterns of disease and information transmission are likely between bats of the same genus despite sharing a common habitat. The clear partitioning of the woodland amongst social groups, and their apparent reliance on small patches of habitat for roosting, means that localised woodland management may be more important to bat conservation than previously recognised.
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Dispersion and habitat use by Myotis daubentonii and Myotis nattereri during the swarming season: implications for conservation
We radio-tracked 24 Myotis daubentonii and 35 Myotis nattereri during the swarming season to determine the catchment area of a swarming site and to study habitat preferences of the bats so that important foraging habitats within the catchment area could be identified. Sixty-one percent of individuals were relocated and 39 day roosts were found for 31 bats. Maximum range from the swarming site was 26.7 km for M. daubentonii and 24.8 km for M. nattereri . Minimum convex polygons depicting the minimum catchment area of the swarming site measured 254 km 2 for M. daubentonii and 497 km 2 for M. nattereri . Including recoveries of ringed bats increases the area enclosed by the maximum range to at least 4118 km 2 . Compositional analysis of habitat used in relation to that available suggested selection of mixed agricultural areas by M. nattereri . Broad-leaved woodland was preferred for foraging. Parkland, woodland and open-water habitats were common around roosts of M. daubentonii . Such habitats should be conserved and enhanced to protect these species. Some individuals of both sexes returned to the swarming site of capture, but none visited another swarming site. Bats may be faithful to only one site and may be inflexible should that site be destroyed. Because the catchment area of swarming sites is large, such sites are probably important centres of outbreeding. Protection of these mating sites should be a conservation priority, and key habitats should be protected over a large area around swarming sites.
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Body weight provides insights into the feeding strategy of swarming bats.
Temperate bat species that hibernate in underground sites are known to visit hibernacula in late summer where they perform an activity known as "swarming". We analysed trends in body mass-to-forearm ratio - the body condition index (BCI) - to investigate whether bats arrive at swarming sites following intensive nocturnal feeding. In a two-year study, Myotis daubentonii , M. brandtii and M. dasycneme were captured by mist-net at one swarming site from late July until early October. In late summer, the BCIs of captured males, females and subadult bats were positively correlated to the time of their capture during the night. In September, adult bats had higher BCIs than in late summer and the BCI did not increase during the night. For subadult M. daubentonii , the BCI was positively correlated to the time of capture in early autumn. Our results indicate that in late summer bats feed intensively during the first hours of the night before visiting swarming sites. In early autumn, subadult bats may go on feeding to complete fat accumulation.