Role of Ipsdienol, Ipsenol, and cis-Verbenol in Chemical Ecology of Ips avulsus, Ips calligraphus, and Ips grandicollis (Coleoptera: Curculionidae: Scolytinae)
Journal of Economic Entomology
Stressed or damaged pine (Pinus sp.) trees in the southeastern United States are often colonized simultaneously by three southern Ips species (Coleoptera: Curculionidae: Scolytinae): small southern pine engraver, Ips avulsus (Eichhoff); sixspined ips, Ips calligraphus (Germar); and eastern Þvespined ips, Ips grandicollis (Eichhoff). All three species mediate colonization of host material with volatile pheromones. All of the southern Ips produce cis-verbenol, and either ipsdienol or ipsenol, and
... nol or ipsenol, and electrophysiological studies have demonstrated that all three southern Ips are able to detect all three compounds. This study examined the role of ipsdienol, ipsenol, and cis-verbenol in the chemical ecology of the southern Ips in Georgia and Louisiana. The most attractive blends of pheromones, with the fewest number of components, were ipsdienol plus ipsenol for I. avulsus, cis-verbenol plus ipsdienol for I. calligraphus, and either cis-verbenol plus ipsenol or ipsdienol plus ipsenol for I. grandicollis. Cross-attraction of I. grandicollis to the pheromone blend most attractive to I. avulsus was observed. Although the presence of heterospeciÞc pheromone reduced the catches of all three species (i.e., the tertiary blend captured fewer beetles than the most attractive binary blends) in both states (signiÞcantly in two cases), high numbers of all three species were still captured in traps baited with all three compounds. These results suggest that the pheromones cis-verbenol, ipsdienol, and ipsenol can be combined for monitoring all three species of the southern Ips simultaneously. KEY WORDS Ips, aggregation pheromone, reproductive isolation, Scolytidae Engraver beetles (Coleoptera: Curculionidae: Scolytinae: Ips DeGeer) spend most of their lives under bark in the trunk and larger branches of dead, dying, downed, or stressed pines (Pinus spp.) where adults mate and larvae feed and develop on phloem tissue (Furniss and Carolin 1977) . Males are the pioneer sex and tunnel into the phloem, excavate a nuptial chamber, and release an aggregation pheromone to attract conspeciÞcs. This pheromone-mediated mass attack behavior facilitates the rapid location and exploitation of available host material and the successful colonization of living pines. The use of trade names and identiÞcation of Þrms or corporations does not constitute an ofÞcial endorsement or approval by the United States Government of any product or service to the exclusion of others that may be suitable.