''Diachasma alloeum'' is a small wasp in the family

Braconidae The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

. It is a

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

of ''Rhagoletis pomonella'', the

apple maggot The apple maggot (''Rhagoletis pomonella''), also known as the railroad worm (but distinct from the '' Phrixothrix'' beetle larva, also called railroad worm), is a species of fruit fly, and a pest of several types of fruits, especially apples. ...

. The wasp lays its eggs into third-instar larvae of the fly, which then develop after the larvae have pupated. The immature wasps then eat the fly larvae and overwinter inside the fly puparia. ''D. alloeum'' wasps attacking ''R. pomonella'' in apples appear to be undergoing a

speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...

event in concert with their hosts. This is an example of sequential

sympatric speciation Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organi ...

References

Braconidae Hymenoptera of North America Insects described in 1956 {{Ichneumonoidea-stub