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Abstract-Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses and coupled GC-mass spectrometry (MS) of volatiles produced by male and female West Indian sugarcane weevils (W1SW), Metamasius hemipterus sericeus (Oliv.), revealed eight male specific, EAD-aclive compounds: 3-pentanol (1), 2-methyl-4-heptanol (2), 2-methyl-4-octanol (3), *To whom correspondence should be addressed. 'Current address: Department of Chemistry, University of Costa Rica, 2060 San Pedro, San Jose, Costa Rica. 4-methyl-5-nonanol (4), and the corresponding ketones. In field experiments in Florida, alcohols 1-4 in combination with sugarcane were most attractive, whereas addition of the ketones or replacement of alcohols with ketones significantly reduced attraction. In Costa Rica field experiments testing alcohols 1-4 singly and in all binary, ternary, and quaternary combinations revealed 4 in combination with 2 was the major aggregation pheromone, equally attracting male and female WISW. Stereoisomeric 4 and (45,5S)-4, the only isomer produced by WISW, were equally attractive. Addition of 4S-, 4R-or (±)-2 to (4S,5S)-4 significantly enhanced attraction. Sugarcane stalks in combination with 2 plus 4 (ratio of 1:8) were highly synergistic, whereas EAD-active sugarcane volatiles ethyl acetate, ethyl propionate, or ethyl butyrate only moderately increased attractiveness of the pheromone lure.

In commercial oil palm plantations in Costa Rica, we tested the hypotheses that pupation site and emergence time affect the mating success of protogynous female bagworms, Oiketicus kirbyi (Guilding) (Lepidoptera: Psychidae). Greater proportions of female than male pupae on upper leaves of oil palms and greater proportions of mated females in the upper rather than lower crown strata support the hypothesis that selection of pupation site by female larvae influences the mating success of adults. Increasing captures of males with increasing trap height further suggest that enhanced mating success of females in tree tops may be attributed either to most effective dissemination of sex pheromone on higher sites, or to males foraging predominantly in the upper strata of oil palms. As the majority of females pupated in the middle rather than upper crown of oil palms, selection of pupation site by females may be affected by additional as yet unknown factors. Emergence of females significantly preceded emergence of males. Increasing proportions of mated females throughout the emergence season probably resulted from an increased ‘availability’ of males. In tropical rainforests with local variations in O. kirbyi developmental time and stage, protogyny may represent an evolutionary strategy that furthers outbreeding.

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