Evidence for a Male-Produced Aggregation Pheromone in Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae)

Abstract

Olfactory response of male and female Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae) to volatiles released from the same or opposite conspecifics alone, or combined with host plant volatiles, was evaluated in the laboratory and field. We also evaluated the response to synthetic Rhynchophorinae pheromones in the laboratory. In laboratory tests, attraction of males and females in Y-tube olfactometer to conspecific males was greater than to females and clean air. Males and females preferred the combination males + agave over agave alone. Both sexes were significantly attracted to 2-methyl-4-heptanol and 2-methyl-4-octanol compared with hexane control. In field trials, weevils were successfully caught in the traps baited with conspecifics and plant material. These field results support those of the laboratory bioassays, showing that males attracted conspecific males and females and addition of plant material enhanced the attraction. These results further suggest that S. acupunctatus produces an aggregation pheromone.

Factors Affecting Pheromone Release byScyphophorus acupunctatus(Coleoptera: Curculionidae)

“…This Þnding explains our previous Þeld trapping results, where traps baited with live males feeding on agave captured more weevils than traps baited with males feeding on apple (RuizMontiel et al 2003). The results of our study, together with those of Ruiz-Montiel et al (2003), suggest that S. acupunctatus males are able to vary the amount of pheromone they release depending on the suitability of the host plant.…”

“…Recent studies on the chemical ecology of this insect have shown that males release a pheromone that attracts both sexes (Ruiz-Montiel et al 2003, 2008. Analysis by coupled gas chromatographyÐ electroantenographic detection of male efßuvia showed the presence of four active peaks that were identiÞed as 2-methyl-4-heptanol, 2-methyl-4-octanol, 2-methyl-4-heptanone, and 2-methyl-4-octanone.…”

“…Field experiments showed that all compounds are attractive to both sexes of S. acupuncatus. However, either the major component, or two ketones, is sufÞcient to obtain captures equivalent to those of the quaternary blend (Ruiz-Montiel et al 2008). Plant volatiles seem to be important in enhancing weevilsÕ attraction to pheromones because traps baited with the binary blend of ketones with agave captured signiÞcantly more weevils than traps baited with the binary blend alone or agave alone (RuizMontiel et al 2008).…”

Influence of Tillage on Adult and Immature Pea Leaf Weevil (Coleoptera: Curculionidae) Densities in Pea

“…Initial host plant consumption by males in some species of weevils leads to the synthesis of an aggregation pheromone (Jaffe et al 1993), whereas for other weevil species host plant consumption is not required to synthesize these pheromones (Ruiz-Montiel et al 1993). Adult pea leaf weevils seem to rely on initial site selection by males (Blight andWadhams 1987, Quinn et al 2000) followed by continued male and female colonization as Þeld conditions become adequate for reproduction and oviposition.…”

Effectiveness of Odor-Baited Trap Trees for Plum Curculio (Coleoptera: Curculionidae) Monitoring in Commercial Apple Orchards in the Northeast

“…The responses of S. incurrens females and males to volatiles of conspecifics and sugarcane were evaluated in a glass Y-tube olfactometer following the method described by Ruiz-Montiel et al (2003). The olfactometer (stem, 12 cm; arms, 12 cm at 45°; internal diameter, 2.5 cm) was placed in an air-conditioned room (22 ± 2 °C, 70 ± 10% RH, and illumination 3 lux).…”