ELECTROPHYSIOLOGICAL AND BEHAVIORAL EVIDENCE FOR A SEX-PHEROMONE IN THE WASP BEPHRATELLOIDES POMORUM

Field experiments showed that males of the seed-feeding, Neotropical w asp Bephratelloides pomorum are strongly attracted to females. That th is attraction was semiochemically mediated was demonstrated by both th e response of male antennae to the whole-body extract of females and b y behavioral bioassays. In the field, males were captured in traps bai ted with female thoraces, but not with other body parts (abdomen and h ead). Volatiles collected from the headspace of female wasps or whole- body extracts, concentrated and transferred to cotton plugs, elicited a full sequence of sexual behavior in male wasps. The attraction of ma les to female-baited traps showed a peak of activity at noon, but in i ndoor bioassays male responded to female extracts even at night.