A case of ecological specialization in ladybirds:Iberorhyzobius rondensis(Coleoptera: Coccinellidae), potential biocontrol agent ofMatsucoccus feytaudi(Hemiptera: Matsucoccidae)

Abstract

AbstractSpecialization is an important attribute of a biological control agent. The maritime pine bast scale,Matsucoccus feytaudiDucasse (Hemiptera Matsucoccidae), is an invasive species in Southeast France and the North of Italy.Iberorhyzobius rondensisEizaguirre (Coleoptera: Coccinellidae), is a recently described ladybird species. Both adults and larvae are predaceous, feeding on egg masses ofM. feytaudi, and are strongly attracted toM. feytaudi’s sex pheromone. To evaluate the potential ofI. rondensisas a biocontrol agent of the scale, we studied its niche breadth and prey range with emphasis on pine forests and hemipterans as tested prey. In this study,I. rondensiswas found to achieve complete development only when fed onM. feytaudiegg masses (92.9% survival) and an artificial prey: eggs ofEphestia kuehniellaZeller (27.6% survival). From the 2nd instar onwards, complete development could be achieved using other prey species, although larvae had significantly higher mortality and slower development. In choice tests,M. feytaudiwas the preferred prey. Surveys of the ladybird populations in the Iberian Peninsula revealed that it was found exclusively onPinus pinasterAiton, the sole host ofM. feytaudi. The unusual specialization ofI. rondensis, among other predaceous ladybirds, makes it an appropriate candidate for classical biological control ofM. feytaudi.