The parasitic fly Nemorilla maculosa exploits host‐plant volatiles to locate the legume pod borer, Maruca vitrata

N emorilla maculosa M eigen ( D iptera: T achinidae) is a solitary endoparasitoid of the legume pod borer, M aruca vitrata F abricius ( L epidoptera: C rambidae), a key pest of cowpea, V igna unguiculata (L.) Walp. ( F abaceae) in A frica. A colony of N . maculosa , introduced for experimental purposes from T aiwan to the laboratories of the International Institute of Tropical Agriculture ( IITA ) in Benin, was used for our studies. Olfactory reponses of N . maculosa to leaves of infested or uninfested cowpea and yellow peabush, S esbania cannabina ( R etz.) Pers. ( F abaceae), and to M . vitrata larvae were evaluated in a four‐arm olfactometer. For all combinations of odor sources, responses between naïve and oviposition‐experienced female flies did not differ. N emorilla maculosa females were attracted by odors from uninfested leaves of yellow peabush and flowers of cowpea when compared with clean air, and they were attracted to plants damaged by M . vitrata with larvae removed. However, the female fly did not discriminate between odors from infested and uninfested plants. The parasitic fly N . maculosa proved well able to use volatile compounds from various host plants (peabush and cowpea) to locate its host, with a more pronounced attraction by the combination of host larvae and infested host plant parts. These findings are discussed in light of the prospective use of N . maculosa as a biological control agent against the legume pod borer.