Egg-dumping lace bugs preferentially oviposit with kin.

Egg dumping, or abandoning eggs and young to the care of other conspecifics, results in an extreme form of alloparental care. It is unclear, however, if egg dumpers discriminate among kin and nonkin egg recipients. In the lace bug Gargaphia solani (Heteroptera: Tingidae), some females with eggs (guards) also accept and defend eggs of conspecifics. Other females (egg dumpers) abandon their offspring after oviposition, leaving a single guard as the caregiver. We asked if egg dumpers preferentially dump their eggs among unguarded eggs of kin or nonkin. When given a choice between dumping among eggs of full siblings and eggs of nonsiblings, most eggs (67%) were dumped with full siblings' eggs. Furthermore, egg dumpers were just as likely to oviposit among eggs of kin with whom they had interacted on a shared host plant during juvenile development as they were to oviposit with kin reared on different host plants. Thus, egg dumpers discriminate kin by using cues associated with eggs, and such cues are not likely to be acquired through interaction on a common host plant environment. Copyright 2000 The Association for the Study of Animal Behaviour.