Does host plant influence parasitism and parasitoid species composition inLygus rugulipennis? A molecular approach

Abstract

AbstractLygusHahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. EuropeanPeristenus digoneutisLoan andP. relictusRuthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program forLygus. The attractiveness of different host plants to EuropeanPeristenushas not been addressed, but may be an important consideration prior to parasitoid release.Lygus rugulipennisPoppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratenseL.; Fabaceae) and chamomile (Matricaria recutitaL.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativaL.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay forP. digoneutis,P. relictus, andP. pallipesCurtis. Mean parasitism levels inL. rugulipenniswere 45–49% in the NTA ecoregion and 25–32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact thatP. digoneutisandP. relictusshare the same host species.