Host Volatile Percepts of Two Sympatric Longhorned Beetles, Anoplophora Chinensis and Anoplophora Glabripennis

Abstract

Anoplophora chinensis (CLB) and Anoplophora glabripennis (ALB) are sympatric sibling species of pest lamiine cerambycids. Both are destructive invasives under strong domestic and international focus. Monitoring lures for both species need improvement. Under the current ratio hypothesis of insect host detection, insects orient towards their hosts via identification of a host-indicative, attractive blend of multiple volatile compounds. I evaluated multivariate statistical comparison of host versus non-host hardwood volatiles as a method for simultaneously identifying host-indicative compounds for both species. Statistical methods determined the commercially unavailable (E)-4,8-dimethyl-1,3,7-nonatriene was indicative of CLB hosts and a multicomponent blend including benzyl acetate, α-humulene, (E)-nerolidol, (E)-caryophyllene, isoamyl benzoate, and 6-methyl-5-hepten-2-ol was indicative of ALB hosts. I hypothesized that the CLB host indicative blend is inclusive of the ALB host indicative blend and tested the six ALB host-indicative compounds for attraction to both species in Bengbu, China. Field trapping treatments were host volatiles only, male pheromone only, host volatiles + pheromone, and isopropanol control. Pheromone containing treatments captured significantly greater numbers of CLB with the host volatile + pheromone treatment capturing the greatest number of CLB. To further examine intraspecies chemical communication between ALB and CLB, cuticular hydrocarbon extracts from ALB and CLB were collected. Stepwise discriminate analysis showed differences in samples by species and sex, illustrating that ALB and CLB males and females can be identified by their cuticular extracts. In addition, principle component analysis indicated ALB cuticular hydrocarbon samples collected from beetles from Hunchun, Jilin, diverged from the rest of the samples. This research found supporting evidence for the ratio hypothesis of insect host detection, characterized the cuticular hydrocarbons of ALB and CLB, and identified potential geographic variation in ALB cuticular hydrocarbons