Host specificity and performance on different hopper species of the egg parasitoid Anagrus virlai

Abstract

The performance of A. virlai on six Cicadellidae and three Delphacidae (Hemiptera) species was assessed under laboratory conditions to clarify its host specificity. In addition, the influence of host egg size on the body size and egg load of the emerging parasitoids was investigated. The Deltocephalinae (Cicadellidae) Amplicephalus marginellanus (Metcalf), Amplicephalus dubius Linnavuori and Dalbulus maidis (DeLong & Wolcott) were the most parasitised species. Wasps were unable to parasitise the eggs of the Cicadellinae (Cicadellidae) Hortensia similis (Walker), Plesiommata mollicella (Fowler) and Scopogonalia subolivacea (Stål) or successfully develop in the eggs of A. marginellanus. The parasitism and emergence rates recorded in Delphacodes kuscheli Fennah, Metadelphax propinqua (Fieber) and Peregrinus maidis (Ashmead) (Delphacidae) were lower than in the other parasitised species. Of all the Cicadellidae tested, S. subolivacea laid the largest eggs and D. maidis the smallest. The Delphacidae deposited the smallest eggs of all hopper species evaluated as hosts. Parasitoids emerged from the eggs of A. dubius were larger and carried higher egg loads than the other wasps reared in A. marginellanus and D. maidis. There was no correlation between most measured morphometric variables and the egg load of wasps. Our results provide valuable insights into the host specificity of this egg parasitoid, but further studies are desirable to fully understand how target and non-target hosts affect the population dynamics of A. virlai in the field.