Community Composition of Longhorned Beetles (Coleoptera: Cerambycidae) in the Canopy and Understorey of Sugar Maple and White Pine Stands in South-Central Ontario

Abstract

Insects of forest canopies are poorly known, especially in temperate forests of eastern North America. From June to August 2001, we sampled Cerambycidae using paired canopy and understorey flight-interception traps in nine pine and nine maple sites in south-central Ontario. Canopy traps were set using a simple ground-based bow-and-arrow method, and averaged 24.5 m in height at pine sites and 20.5 m at maple sites. In total, 297 individuals from 28 species were collected during 6 wk of sampling. Clytus ruricola (Olivier) accounted for 37% of all individuals. Pine sites had more species and higher expected richness than maple sites but significantly fewer individuals. Ten species were unique to pine, six to maple, and 12 occurred in both forest types. The two trap heights had similar observed richness, but expected richness was higher for canopy than understorey traps. Understorey traps accumulated significantly higher abundances than canopy traps. Eleven species were unique to canopy traps, 11 to understorey traps, and six occurred at both heights. Species accumulation was much faster when both heights were sampled compared with either alone. Anthophylax attenuatus (Newman), which has been rarely caught in other studies, was collected only in the canopy and was relatively abundant. Top collecting bottles on traps yielded similar observed richness as bottom bottles but had higher expected richness. Several species showed strong associations with either top or bottom collecting bottles. Species accumulation rates appeared to be higher than in other studies. Our results emphasize the necessity of including the canopy fauna in diversity studies.