Mother-offspring food transfer in Coelotes terrestris (Araneae, Agelenidae)

Three different modes of maternal food supply have been reported in the subsocial agelenid species Coelotes terrestris: prey provisioning, consumption of the mother's body, and regurgitation of nutritive fluids. Although the first two modes are well documented, the latter is not fully assessed. By comparing-in the absence of any prey-the weight variations in spiderlings either left with their mothers or isolated, and by simultaneously comparing the weight variations of mothers, either isolated or left within the group of spiderlings, it was possible to see evidence of a significant and long-lasting food transfer from the mother to her progeny. This food transfer probably explains the high level of survivorship and reduction of cannibalism showed by broods left with their mothers. Close observation provided no direct evidence of mouth to mouth transfer. Rather, the food transfer appears to involve the production and emission of miniature eggs by the mother when in presence of spiderlings, a phenomenon which to date seems not to have been noted among spiders.