
Parasitoid wasps are a diverse group of hymenopteran superfamilies, primarily within the wasp-waisted Apocrita. These wasps lay their eggs on or in other arthropods, leading to the eventual death of the host. They target various insect orders, especially Lepidoptera, and can specialize in different host life stages. Their parasitism is categorized as either endoparasitic (developing inside the host) or ectoparasitic (developing outside).
Parasitoidism evolved once in Hymenoptera during the Permian, leading to a significant number of species across families, including Chalcidoidea and Ichneumonidae. Many parasitoid wasps are beneficial for controlling agricultural pests and have been used in biological pest control since the 1920s.
Some wasps also target spiders and can inject substances that paralyze hosts or protect their eggs from immune responses. Host size is important, influencing the parasitoid’s development and sex ratios. Some species mark hosts with chemical signals to prevent competition.
After hatching, the parasitoid larvae feed on the host, usually killing it by the time they pupate. Adult wasps primarily feed on nectar, with some females consuming hemolymph from hosts for added nutrients.