Umbonia crassicornis (Amyot & Serville, 1843) (Hemiptera: Membracidae) nymphal aggregation size and density affect host plant and treehopper growth

Abstract. There was a significant negative relationship between the density of Umbonia crassicornis (Amyot & Serville, 1843) aggregations and the average length of the newest growth on its host plant, Lysiloma latisiliquum Benth. (Fabaceae). There was also a significant negative relationship between aggregation size and the dry mass of the teneral adults of both sexes. Teneral female U. crassicornis were significantly longer and had a significantly greater dry mass than their male siblings. I suggest that feeding by treehopper nymphs reduces the nutrient pool of the host plant, resulting in reduced plant and treehopper growth.