Female body size, fecundity parameters and foundation of new colonies in Anelosimus jabaquara (Araneae, Theridiidae)

As in other social spider species, subadult Aneolosimus jabaquara females f ound new colonies after solitary dispersal. Some individuals, however, usua lly remain and reproduce in their natal nests. To test the hypothesis that large females disperse more often than smaller ones, we compared the body s ize of A. jabaquara females that remained in their natal colonies with thos e that left to build solitary webs. We also compared clutch size. egg diame ter, total egg volume and spiderling size in both conditions. Emigrating fe males were significantly larger and laid larger clutches. The smaller femal es that had not dispersed laid significantly larger eggs, although their to tal egg volume was lower. Spiderlings of solitary females were smaller and had a smaller range of size variation than those from colonies. We discuss the implications of these results in terms of costs and benefits of dispers ion for spiders in different nutritional conditions.