The seasonality and distribution of Neuroptera, Raphidioptera and Mecoptera on oaks in Richmond Park, Surrey, as revealed by insecticide knock-down sampling

Abstract

Twenty-five species of Mecoptera, Raphidioptera and Neuroptera were collected from oak trees by pyrethroid fogging between April and October, and the seasonality of these species is discussed. A total of over 1500 specimens of adults and larvae were obtained at an average density of about 0·43/m². Four of the species of Neuroptera are considered to be relatively uncommon in Britain, yet two of these (Sympherobius pellucidus and Nothochrysa capitata) were caught in large numbers. Apparent dimorphism in Chrysoperla carnea larvae and other difficulties in identifying chrysopid larvae suggest that further work is needed on geographic variation in this group. An analysis of the spatial distribution within the tree canopy indicated that some species show a marked preference to remain near the trunk, possibly for camouflage.