ARS | Publication request: Discrimination by Coptera haywardi (Hymenoptera:Diapriidae) of hosts previously attacked by conspecifies or by the larval parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 17, 2012
Publication Date: July 10, 2012
Citation: Cancino, J., Liedo, P., Ruiz, L., Lopez, G., Montoya, P., Barrera, J.F., Sivinski, J.M., Aluja, M. 2012. Discrimination by Coptera haywardi (Hymenoptera:Diapriidae) of hosts previously attacked by conspecifies or by the larval parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae). Biocontrol Science and Technology. 22(8):899-914.

Interpretive Summary: Fruit flies attack hundreds of fruits and vegetables and are responsible for trade restrictions wherever they occur. Rearing and releasing large numbers of parasitoids is a promising control technique but could be made less costly if more of the fly hosts were attacked during the rearing procedure. Scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida in collaboration with Mexican colleagues from MOSCAMED examined the possibility of exposing hosts to first larval and then pupal parasitoids. Such a scheme would work best if the pupal parasitoids could recognize and avoid fly larvae previously attacked by larval parasitoids. One candidate pupal parasitoid could indeed distinguish such hosts and efforts are underway to integrate it into production facilities in Mexico.

Technical Abstract: Coptera haywardi (Oglobin) is an endoparasitoid of fruit fly pupae that could find itself in competition with other parasitoids, both con- and heterospecific, already resident inside hosts. In choice bioassays, ovipositing C. haywardi females strongly discriminated against conspecifically parasitised Anastrepha ludens (Loew) pupal hosts. They also avoided pupae previously attacked by Diachasmimorpha longicaudata (Ashmead), a larval–prepupal koinobiont endoparasitoid, and the degree of larval-parasitoid superparasitism had no effect on this avoidance. There was no difference in the number of ovipositor insertions when hosts previously parasitised by a conspecific and D. longicaudata were exposed simultaneously. As females aged the degree of host discrimination declined. An ability to discriminate against pupae previously attacked as larvae suggests low levels of both conspecific and heterospecific competition in the field.