Mass killing by female soldier larvae is adaptive for the killed male larvae in a polyembryonic wasp.

Self-sacrifice is very rare among organisms. Here, we report a new and astonishing case of adaptive self-sacrifice in a polyembryonic parasitic wasp, Copidosoma floridanum. This wasp is unique in terms of its larval cloning and soldier larvae.

Sexual complementarity between host humoral toxicity and soldier caste in a polyembryonic wasp.

Defense against enemies is a type of natural selection considered fundamentally equivalent between the sexes. In reality, however, whether males and females differ in defense strategy is unknown. Multiparasitism necessarily leads to the problem of defense for a parasite (parasitoid).

Male soldiers are functional in the Japanese strain of a polyembryonic wasp.

Polyembryonic parasitoids clonally produce sterile soldier larvae in both sexes. Female soldier larvae of Copidosoma floridanum defend their siblings and host resources against heterospecific competitors as well as conspecific male embryos that results in female biased sex ratios. However, the male soldiers of the USA strain exhibit no aggressive behaviors against them, suspected to be a secondary loss of male defense function in the course of evolution.

Physiological suppression of the larval parasitoid Glyptapanteles pallipes by the polyembryonic parasitoid Copidosoma floridanum.

Precocious larvae, clonally produced together with reproductive siblings in the polyembryonic parasitoid Copidosoma floridanum, are known to physically attack competitors in multiparasitized hosts. In this study, we show that physiological suppression by C. floridanum, as well as precocious larval activity, causes death of the larval parasitoid Glyptapanteles pallipes.