Mythimna unipuncta
Mythimna unipuncta, the true armyworm moth, white-speck moth, common armyworm, or rice armyworm, is a species of moth in the family Noctuidae. The species was first described by Adrian Hardy Haworth in 1809. Mythimna unipuncta occurs in most of North America south of the Arctic, as well as parts of South America, Europe, Africa, and Asia. Although thought to be Neotropical in origin, it has been introduced elsewhere, and is often regarded as an agricultural pest. They are known as armyworms because the caterpillars move in lines as a massive group, like an army, from field to field, damaging crops. The true armyworm has a distinct migration pattern in which they travel north in the spring and south in the fall to ensure that mating occurs in a favorable environment in the summer. While progressing through the life cycle stages of egg, larva, pupa, and adult, this species must avoid attack from predatory bugs, birds, wasp and fly parasitoids, and bacterial and fungal diseases. As polygamous insects, females release sex pheromones and choose multiple males as mates. The production and release of the pheromones are influenced by temperature, photoperiod, and the juvenile hormone. Hearing is an important sense for the true armyworm, necessary for mating and evading bat predation. Geographic range M. unipuncta are commonly found around the world including the Americas, southern Europe, central Africa, and western Asia. In North America, they inhabit areas east of the Rocky Mountains and in northern Canada. Food resources Larvae Larvae feed and damage on a variety of Graminae (weedy grasses) and other crops. Hordeum vulgare – barley Maize – corn Oats Rice Rye Sorghum Sugarcane Wheat Alfalfa Artichoke Bean Cabbage Carrot Celery Cucumber Lettuce Onion Parsley Pepper Sweet potato Adults Adults feed on the nectar of various types of flowers and will eat ripe or decaying fruit. Life history Life cycle In a given year, there can be two to three generations, each generation requiring 30–50 days to complete. Egg Adults oviposit in groups of 2 to 5 rows on dry leaves and grass, especially between the leaf sheath and blade. Females may deposit up to 80 eggs per cluster, leading to highly dense larvae populations. Total reproductive capacity for females is between 500-1500 eggs. The egg stage lasts on average 3.5 days in warmer weather and 6.5 days in cooler weather. The eggs appear to be a white or yellowish color but change to a gray hue right before eclosion. A sticky material on the surface of the egg sticks to surrounding foliage and helps hide the eggs. Larvae The true armyworm larval stage lasts at least six instars but may extend to nine. The caterpillar grows from 4 to 35 mm within this stage. The larval stage lasts about 20 days in warmer weather and 30 days in cooler weather. When the larvae hatch, they feed on the foliage on which they were laid, but if disrupted, larvae release silk and fall into the soil. Larvae in the later instars