Improved Population Monitoring of Bark Beetles and Predators by Incorporating Disparate Behavioral Responses to Semiochemicals

Abstract

Estimating populations of both pest and natural enemy species is important in the planning and implementation of biological control. For example, synthetic pheromone lures are used to sample bark beetles, and sometimes their predators, in forest ecosystems. However, insect attraction to natural pheromone sources may differ from attraction to synthetic pheromone lures. Moreover, these differences may vary systematically between the target pest and some important natural enemies. Thus, the accuracy of both absolute and relative abundances of bark beetles and predators could vary with lure selection. We evaluated a series of synthetic lures to determine which lure gave the closest approximation to actual numbers of Ips pini (Say) and predators arriving at hosts infested with I. pini in Wisconsin. We deployed synthetic lures containing various ratios of the (ϩ) and (Ϫ) enantiomers of the principal I. pini pheromone component, ipsdienol, with or without an additional component, lanierone. I. pini showed strong preferences for speciÞc enantiomeric ratios of ipsdienol, and these responses were synergized by lanierone. Predators showed equally strong attraction to ipsdienol, but preferred different ratios of the stereoisomers. The addition of lanierone had no effect on predators. The most abundant predator, Thanasimus dubius (F.), showed greater preference for host material infested with I. pini than any synthetic lure. These disparities in responses, combined with strong disparities in seasonal ßight patterns, provided estimates of pest to predator ratios that varied by as little as 12% to as much as 12 times, from pest:predator ratios arriving at host material infested with I. pini. These results suggest that variation between herbivores and their natural enemies in their phenology, preferred pheromone blends, and infested host material should be considered when developing estimates of relative pest and predator densities for subsequent management options.

Application of Semiochemicals to Assess the Biodiversity of Subcortical Insects following an Ecosystem Disturbance in a Sub-boreal Forest

“…For example, Chrysobothris sexsignata, E. n. rufiventris, and T. nutalli occur in P. resinosa, P. banksiana, and P. strobus stands in the adjacent province of Ontario, Canada (Chénier and Philogène 1989), and I. latidens occurs in Ontario in P. strobus (Bright 1976). Enoclerus muttkowski, E. nigripes, T. undatulus, and Z. sanguineus occur in stands of P. resinosa in the adjacent state of Wisconsin Raffa 2000, 2005;Aukema et al 2000aAukema et al , b, 2004Erbilgin et al 2003) and Z. sanguineus may be associated with a hardwood tree (butternut), J. cinera, in Wisconsin (Katovich and Ostry 1998).…”

“…(Dahlsten 1970;Stephen and Dahlsten 1976a, b); red pine, Pinus resinosa Ait. Raffa 2000, 2005;Aukema et al 2000aAukema et al , b, 2004Erbilgin et al 2003); sugar pine, Pinus lambertiana Dougl. (Dahlsten and Stephen 1974); and white spruce, Picea glauca (Moench) Voss (Whitmore 1982;Gara et al 1995;Haberkern et al 2002).…”

Use of infochemicals in Pest Management with Special Reference to the Banana Weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae)

“…However, data on the role of infochemicals in predator foraging have become available for some groups such as predatory mites (Sabelis and Dicke, 1985;Dicke and Sabelis, 1988), bark beetle predators (Aukema et al, 2000), heteropteran predators (Van Loon et al, 2000) and coccinellids (Liu and Sengonca, 1994;Steidle and van Loon, 2002). The predator Rhizophagus grandis (Gyll.)…”

“…The predator Rhizophagus grandis (Gyll.) (Coleoptera: Rhizophagidae) is attracted to traps baited with a kairomone produced by the bark beetle Dendroctonus micans Kug (Coleoptera: Scotylidae) (Aukema et al, 2000) and in this way the predator distribution in the field can be monitored. The search time of predators may be reduced through increased aggregation at infested sites or kairomone sources (Vet and Dicke, 1992).…”

Olfactory Responses of Banana Weevil Predators to Volatiles from Banana Pseudostem Tissue and Synthetic Pheromone

“…The predator Rhizophagus grandis (Gyll.) (Coleoptera: Rhizophagidae) is attracted to traps baited with a kairomone produced by the bark beetle Dendroctonus micans Kug (Coleoptera: Scolytidae) (Aukema et al, 2000), and this can be exploited to monitor the predator's distribution in the field.…”