Field response of spruce bark beetle,Ips typographus, to aggregation pheromone candidates

Abstract

Abstract--Six compounds previously identified from hindguts of unmated male Ips typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB), cis-verbenol (cV), trans-verbenol (tV), myrtenol (Mt), trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their attractivity in the field with a subtractive method. The amounts of MB and cV released from a pipe trap were similar to those given off from the commercial bait Ipslure as well as that from a Norway spruce tree, Picea abies (L.) Karst., under mass attack. The blend of the compounds became nonattractive when either MB or cV was subtracted, while subtraction of any of the other four compounds bad no effect. Addition of ipsdienol (Id) to the blend did not significantly increase the attraction. In a second comparative test, the addition of three compounds as a group (tV + Mt + PE) to MB + cV again had no effect on the attraction, but the addition of Id increased the catch somewhat. Addition of host logs to a bait releasing MB + cV at a rate lower than in previous experiments did not influence the attraction to pipe traps. Sticky traps containing natural pheromone sources (50 males in a log), which released 1-5 rag/day of MB as determined by aerations with deuterated MB as internal standard, were less attractive than a synthetic source releasing similar amounts of MB.

Host-Tree Chemistry Affecting Colonization in Bark Beetles

“…There is some evidence that I. typographus is weakly attracted to host volatiles (Austara et al, 1986;Lindelow et al, 1992) or monoterpenes such as a-pinene (Rudinsky et al, 1971), but other studies have not observed any attraction to host volatiles or synergism of pheromone and host volatiles (Schlyter et al, 1987a). A computer model by Gries et al (1989), in which "beetles" must take a series of flights between trees in a grid (each flight to one of eight neighboring trees) and test each tree for suitability, showed that few beetles would find the widely scattered hosts designated as susceptible.…”

Orientation of bark beetlesPityogenes chalcographus andIps typographus to pheromonebaited puddle traps placed in grids: A new trap for control of scolytids

“…Based on the release rates for a similar length tube and neat chemicals (Byers et al, 1988), ratio of the areas for dispenser openings (2.53), and the rearranged diffusion-dilution equation 2 above, the expected release (milligrams per day per dispenser) was about 0.15 mg for chalcogran, 0.003 mg for methyl (E,Z)-2,4-decadienoate, and 31 mg for (-)-o~-pinene. For attraction of I. typographus, (1S,4S,5S)-cis-verbenol was released at 1 mg/day/trap and 2-methyl-3-buten-2-ol at 50 mg/day/trap from dispensers described previously (Schlyter et al, 1987c).…”

“…Host-tree compounds are not effective in enhancing the attraction to pheromone components, and uninfested logs in the field are unattractive when beetles are known to be flying (Schlyter et al, 1987c). The smaller European spruce engraver, Pityogenes chalcographus L., is also attracted to a synergistic blend of the pheromone components, chalcogran (2-ethyl-l,6-dioxaspiro[4.4]…”

Peripheral modulation of pheromone response by inhibitory host compound in a beetle

“…They are among the most well-studied insects in terms of behavioral responses to odor blends, such as different combinations of ecologically relevant attractants and inhibitors, and much is known about the peripheral detection of these individual compounds (Andersson et al, 2009;Tømmerås, 1985). (Ips typographus, L.) are induced by release of the male-produced aggregation pheromone, a mixture of (4S)-cis-verbenol (cV) and 2-methyl-3-buten-2-ol (Schlyter et al, 1987). Pheromone attraction is modulated by anti-attractant nonhost volatiles (NHVs) from leaves and bark of angiosperm plants (Zhang and Schlyter, 2004).…”