Evidence for a male-produced aggregation pheromone in Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae).

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.