No abstract

Two related volatile compounds were identified from each of two species ofPissodes bark weevils and implicated as components of their aggregation pheromones. Grandisol (cis-2-isopropenyl-1-methylcyclobutaneethanol), and its corresponding aldehyde, grandisal, were isolated from males of bothP. strobi andP. approximatus and were found in the abdomens and hindguts of the respective species. In field tests synthetic grandisol and grandisal together with odors from cut pine acted synergistically in attracting both sexes ofP. approximatus. This response was similar to that elicited by maleP. approximatus feeding on cut pine. Males and females of natural populations ofP. strobi were more responsive to caged males feeding on leaders of white pine than they were to leaders alone. The combination of grandisol, grandisal, and leaders was less attractive than males on leaders, but more attractive than leaders alone. From isolation of pheromone components at different times of the year, it was determined that males of both species produced grandisol and grandisal only at times when cohort females were reproductively mature.

The bark weevilPissodes nemorensis, a pest of pines and exotic cedars in the southeastern United States, utilizes a male-produced aggregation pheromone. The presumed pheromone components, grandisol (cis-2-isopropenyl-1-methylcyclobutaneethanol) and its corresponding aldehyde, grandisal, were isolated from extracts of male volatiles and male hindguts. A field test in northern Florida showed that the combination of grandisol, grandisal, and slash pine (Pinus elliottii) bolts acted synergistically to attract large numbers of male and femaleP. nemorensis. These components deployed in various paired combinations were not as attractive as the tripartite mixture. There was no evidence that flying weevils were attracted to unbaited pine bolts. The aggregation pheromone forP. nemorensis appears to be similar to that of a parapatric sibling species,P. approximatus.