Endotokia matricida in hermaphrodites of Heterorhabditis spp. and the effect of the food supply

Intra-uterine birth causing maternal death (endotokia matricida) is relativ ely common in rhabditid nematodes and typical for entomopathogenic nematode s of the genus Heterorhabditis. A detailed description of this phenomenon i s given, including a summary of embryo development, egg-laying, juvenile ha tching and development. It is demonstrated that low food supply significant ly promotes the beginning of endotokia matricida but has no influence on th e time scale of the process. The biological function of endotokia I,matrici da and the intra-uterine induction of the dauer formation is discussed. End otokia matricida in Heterorhabditis spp. is a well synchronised process of the destruction of the maternal tissues correlated with the juvenile develo pment including the uptake of the symbiotic bacteria by the late pre-dauer stage. It secures the development of dauer juveniles at a moment when the e xternal food supply is reducing and provides offspring which are well equip ped with energy reserves and symbiotic bacteria for long term survival and subsequent infection of insects in the soil.