Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae): biologia e predação de Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae)

Abstract

Predatory bugs (Anthocoridae) are an important group for potential use in biological control of thrips. The pirate bug Montandoniola confusa (= moraguesi) Streito & Matocq (Hemiptera: Anthocoridae) is found preying on Cuban laurel thrips, Gynaikothrips ficorum, (Marchal) (Thysanoptera: Phlaeothripidae). The aim of this work was to study the biology of M. confusa feeding on G. ficorum (its natural prey) and eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Gelechiidae) and Sitotroga cerealella Oliver (Lepidoptera: Pyralidae) as factitious prey. The predator M. confusa showed lower nymphal duration when feeding on G. ficorum and A. kuehniella, and the egg production was 2.37 times greater when reared on G. ficorum. It was determined the predation rate of M. confusa preying upon different development stages of thrips, exposed separately or simultaneously for 48 hours. Estimated by the functional response model, the average predation rate was 110.5 eggs, 10.9 larvae/pre-pupae and 13.5 adults, when these stages were offered separately. Exposing simultaneously all stages of prey in the galls and in different proportions was observed higher predation rate on eggs with significant reduction in predation of larvae and adults, after increasing the availability of eggs. The presence of adults of thrips in galls having low density of eggs (less than 30 eggs per gall) did not affect the predation rate on eggs by M. confusa. However, at densities greater than 90 eggs per gall, the presence of adult thrips reduced by up to 50% the predation rate on eggs. It is concluded that M. confusa is specialized to prey on eggs regardless of the density of eggs, larvae or adults of thrips in the gall. Eggs of A. kuehniella and S. cerealella may be used to rear M. confusa, but with lower performance if compared to the natural prey. Among the available alternative prey, A. kuehniella have been shown to be the most suitable alternative prey species for rearing M. confusa.