Olfactory behavior and receptor potentials of the khapra beetleTrogoderma granarium (Coleoptera: Dermestidae) induced by the major components of its sex pheromone, certain analogues, and fatty acid esters

Abstract

On the basis of the antennal receptor potentials and the extent of attraction and copulation induced in unmated male khapra beetles, (Z)- and (E)-14-methyl-8-hexadecenal were recognized as the most important components of the pheromone system of femaleTrogoderma granarium (Everts), and were named (Z)- and (E)-trogodermal. Air blown over 10−5 to 10−4 μg of (Z)-trogodermal produced receptor potentials equivalent to that elicited by one virgin femaleT.granarium, while ∼10−2 μg of (Z)-trogodermal was required to cause complete attraction and copulation of unmated males. (Z)-Trogodermal was about 10 times more active than (E)-trogodermal. (Z)-8-Hexadecenal was ∼10−2 times less effective than (Z)-trogodermal in causing attraction and 104 time less active in stimulating copulation. (Z)- and (E)-14-methyl-8-hexadecen-1-ol and methyl (Z)- and (E)-14-methyl-8-hexadecenoate displayed a relatively low activity for unmated male khapra beetles. Methyl and ethyl oleate, ethyl linoleate, ethyl palmitate, and ethyl stearate were less effective than (Z)-trogodermal by 6–8 orders of magnitude and are nonspecific attractants. The intensity of response to a particular compound was consistent when assessed by the essential components of mating behavior: receptor potentials, attraction, and copulation.