Olfactory reception of conspecific aggregation pheromone and plant odors by nymphs of the predator, Podisus maculiventris

Olfactory reception of 23 odorants, including plant volatiles and male-prod uced aggregation pheromone, by third and fifth instars of the spined soldie r bug (SSB) Podisus,maculiventris was investigated by using electroantennog rams (EAGs). Both nymphal stages were sensitive to male-produced aggregatio n pheromone components (E)-2-hexenal, benzyl alcohol, and alpha-terpineol. The plant volatile, (E)-2-hexen-1-ol (a chemical known to be released by pl ants in response to prey feeding over the short-term), elicited the largest EAGs of all volatiles tested. While third instars were sensitive to nonana l, only fifth instars responded to both nonanal and (+/-)-linalool, both co mpounds released systemically by plants in response to feeding by potential prey. Antennal extirpation experiments showed that sensilla responsive to hexan-1-ol, (E)-2-hexenal, and cu-terpineol are situated mainly on the term inal antennal segment. The results support the hypothesis that P. maculiven tris nymphs use both plant volatiles and pheromone components in locating p otential prey and other behaviors.