Role of Volatile Semiochemicals in the Host and 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 oak, sweetgum, sugarberry and hackberry; although they also colonize a variety of other hardwoods. Here, we study the mate location behavior of M. dasystomus by testing the hypotheses that the sexes are mutually attracted to volatiles emanating from the larval host and that females release a volatile pheromone that is attractive to males alone. In a Y-tube olfactometer, male and female M. dasystomus responded to volatiles from host material (i.e., sweetgum and sugarberry). However, only males responded to females in the olfactometer, suggesting that females release a volatile sex pheromone. In choice experiments conducted in a greenhouse, we determined that both males and females prefer host over non-host material. In further bioassays in the greenhouse, males chose host material containing a live female over that containing a live male or host material alone. These findings are further evidence of the critical role host volatiles and pheromones play in mating systems of longhorned beetles.