CHEMICAL AND BEHAVIORAL ECOLOGY OF PALM WEEVILS (CURCULIONIDAE, RHYNCHOPHORINAE)

Palm weevils in the subfamily Rhynchophorinae (Curculionidae) (Rhyncho phorus spp., Dynamis borassi, Metamasius hemipterus, Rhabdoscelus obsc urus, and Paramasius distortus) use male-produced aggregation pheromon es for intraspecific chemical communication. Pheromones comprise 8, 9, or 10 carbon, methyl-branched, secondary alcohols. (4S,5S)-4-Methyl-5 -nonanol (ferrugineol) is the major aggregation pheromone for R. ferru gineus, R. vulneratus, R, bilineatus, M. hemipterus, and D. borassi an d a minor component for R. palmarum. (5S,4S)-5-Methyl-4-octanol (cruen tol), (3S,4S)-3-methyl-4-octanol (phoenicol), and (4S,2E)-6-methyl-2-h epten-4-ol (rhynchophorol) are the main aggregation pheromones for R. cruentatus, R. phoenicis, and R. palmarum, respectively. Plant kairomo nes strongly enhance pheromone attractiveness but none of the identifi ed volatiles, such as ethyl acetate, ethyl propionate, or ethyl butyra te are as synergistic as fermenting plant (palm or sugarcane) tissue. Studying orientation behavior of foraging weevils to semiochemical dev ices helped to design and test traps for weevil capture. Generally, 3 mg per day of synthetic pheromone (with non-natural stereoisomers bein g benign) plus insecticide-treated plant tissue constitute highly attr active trap baits. Potential exists for pheromone-based mass-trapping of weevils to reduce their populations and the spread of the weevil-ve ctored red ring disease, for monitoring their population dynamics to f acilitate pest management decisions, and for detection and possible in terception of non-native weevils at ports of entry.