Over half of all species of Hymenoptera are parasitoids. Host for Hymenopteran parasitoids are not exclusively insects. Some parasitize and develop on spiders and ticks. Ixodiphagus hookeri is an encyrtid wasp that uses Ixodes Spp. as hosts. Female wasps lay numerous eggs inside a tick. These develop on the tick tissues, eventually killing their host. The wasps pupate and emerge inside the tick. The adult wasps chew a hole in the tick cuticle to escape.
Ixodiphagus hookeri has attracted interest because the hosts are vectors of Lyme disease. Attempts to reduce natural populations of Ixodes ticks by rearing and releasing Ixodiphagus hookeri have not been successful to date.