Role of Ipsdienol, Ipsenol, and <I>cis</I>-Verbenol in Chemical Ecology of <I>Ips avulsus</I>, <I>Ips calligraphus</I>, and <I>Ips grandicollis</I> (Coleoptera: Curculionidae: Scolytinae)

Abstract

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 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, ScolytidaeEngraver 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.

Response of the Woodborers <I>Monochamus carolinensis</I> and <I>Monochamus titillator</I> (Coleoptera: Cerambycidae) to Known Cerambycid Pheromones in the Presence and Absence of the Host Plant Volatile α-Pinene

“…Among many insects, the behavioral mechanisms that facilitate pair formation are hypothesized to be the same as those that prevent hybridization. For example, specificity of pheromone response has been hypothesized to mediate mate location and reproductive isolation in bark beetles (Lanier and Wood 1975; but see Allison et al 2012b). The observation that the sympatric species M. carolinensis and M. titillator rely on the same mechanism for mate location (monochamol) suggests that in these species, the mechanisms involved in mate location and reproductive isolation may differ.…”

Flight Phenologies of the Southeastern <I>Ips</I> Species (Coleoptera: Curculionidae: Scolytinae) and Some Associated Coleoptera in Central and Southern Louisiana

“…Some evidence supporting this hypothesis is provided in this study based on the observed frequencies of I. avulsus and I. grandicollis (represented by the LSD lure combination) relative to I. calligraphus (represented by the VD lure combination), with higher combined seasonal trap catches of I. avulsus and I. grandicollis equaling 234,180 compared with 48,581 individuals of I. calligraphus. Lower numbers of I. calligraphus relative to I. avulsus and I. grandicollis have been observed in other studies as well (e.g., Miller et al 2011, Allison et al 2012b. Additional trapping studies are necessary to fully test this hypothesis.…”

“…It was, however, worthwhile to note when clear preferences were observed. The lure combinations used in this study were modiÞed from earlier studies targeting the southern Ips species (Miller et al 2005, Allison et al 2012b) and were successful in attracting each of the target species, with relatively few individuals collected in traps baited with the other lure combination.…”

“…Within each site, traps were paired and baited randomly with the two possible combinations of synthetic Ips pheromone lures (Contech Enterprises Inc.). Lure combinations were based on results of previous trapping assays (Miller et al 2005, Allison et al 2012b) and were selected to optimize attraction with the minimal number of trapÐlure combinations. To attract I. grandicollis and I. avulsus, traps were baited with a combination of bubble cap lures containing lanierone (L) and racemic (ϭ50:50 mix of the two enantiomers) ipsenol (S), and ipsdienol (D) (chemical purities Ͼ98%; hereafter treatment LSD).…”

Biology of the bark beetleIps grandicollis Eichhoff (Coleoptera:Scolytinae) and its arthropod, nematode and microbial associates: a review of management opportunities forAustralia

“…Ipsenol and cis‐ verbenol play an important role as aggregating pheromones for both sexes (Vité & Renwick ; Neumann & Morey ; Dodds & Miller ; Allison et al . 2012b). Ipsenol is the key pheromone component for both sexes, while E ‐myrcenol is only detected by female beetles and may act as a sex pheromone, rather than an aggregation pheromone component (Birgersson et al .…”