Role of host plant volatiles and attractant pheromones in the mate location behavior of Mallodon dasystomus (Coleoptera: Cerambycidae)

Little is known of the role semiochemicals play in the mating systems of longhorned beetles (Coleoptera: Cerambycidae) in the primitive subfamily Prioninae. Mallodon dasystomus (Say), the hardwood stump borer, is a widely distributed prionine native to the southern US. Preferred hosts of M. dasystomus include sugarberry, sweetgum and hackberry; although they are capable of also colonizing oak, sycamore, hickory, willow, boxelder, and in some instances, conifers. In this study, we explore the mate location behavior of M. dasystomus and test the hypothesis that the sexes are attracted to volatiles produced by the larval host plant. We further test the hypothesis that, once on an appropriate host, females release a volatile pheromone to attract potential mates. In a Y-tube olfactometer, male and female M. dasystomus responded to volatiles emanating from freshly cut sweetgum and sugerberry. To test for attractant pheromones, we measured the response of individual males and females to three screen cages, each containing a bolt of freshly cut sweetgum. One cage also contained ten adult female M. dasystomus, a second contained ten adult males, and the last contained only a bolt of sweetgum. Males alone responded most strongly to the cages containing females on the host log, suggesting that females release a volatile sex pheromone. These findings are further evidence of the critical role host volatiles and pheromones play in mating systems of longhorned beetles.