Trophic egg laying in the spider, Amaurobius ferox: mother-offspring interactions and functional value

Offspring of the spider Amaurobius ferox (Araneae, Amaurobiidae) were provi ded with trophic eggs of their mother the day after their emergence from th e egg sac. This precisely timed egg laying followed after a series of mothe r-offspring interactions involving specific behaviors. Experiments showed t hat the trophic egg laying of the mother (providing she is in the appropria te reproductive condition) necessitated not only their presence, but also t he stimulating behavior of the spiderlings. By stimulating their mother the spiderlings actually inhibited the normal maturation of the second generat ion of maternal eggs and prompted the release. Comparing to the trophic egg -deprived clutches, the clutches provided with the trophic eggs developed w ith higher body mass, earlier moulting and matriphagy. More offspring survi ved at the matriphagy with the mother normally provisioning the first clutc h with trophic eggs rather than with the mother that did not produce the tr ophic eggs for her first clutch but for her second clutch. By turning her p otential second generation into food, the mother increases her reproductive success. (C) 2000 Published by Elsevier Science B.V. All rights reserved.