COMPARATIVE ELECTROPHYSIOLOGICAL STUDIES OF OLFACTION IN PREDACEOUS BUGS, PODISUS-MACULIVENTRIS AND P-NIGRISPINUS

Electroantennograms (EAGs) were recorded from both sexes of spined sol dier bug (SSB), Podisus maculiventris, and Brazilian SSB (BSSB), P. ni grispinus to determine antennal olfactory responsiveness of 23 compoun ds in SSB and 14 compounds in BSSB, including the multicomponent male- produced aggregation pheromone and plant volatiles. EAGs of both speci es were similar. (E)-2-Hexenol and (E)-2-hexenal elicited the greatest EAGs, followed by heptanol, nonanal, hexanal, and the pheromonal comp ounds, (+/-)-alpha-terpineol and benzyl alcohol. Both sexes of SSB and BSSB were more sensitive to components of the male-produced aggregati on pheromone [(+/-)-alpha-terpineol, (+/-)-linalool, and benzyl alcoho l] and nonanal than either (E)-2-hexenol or (E)-2-hexenal (a component of the aggregation pheromone). BSSB were more sensitive to (+/-)-alph a-terpineol, (+/-)-linalool, benzyl alcohol, and nonanal than were SSB . EAGs to the plant volatile 1-hexanol and the pheromonal components ( E)-2-hexenal and (+/-)-alpha-terpineol decreased significantly with re moval of antennal segments, suggesting that receptors for these compou nds are distributed over the distal three segments of the five-segment ed antennae.