Identification of a Male-Produced Aggregation Sex Pheromone in Rosalia batesi, an Endemic Japanese Longhorn Beetle.

The longhorned beetle Rosalia batesi Harold (Coleoptera; Cerambycidae) is endemic to Japan, where its range extends from Hokkaido to Kyushu. The colorful adults are well-known to entomologists and collectors worldwide. It is a hardwood-boring species with larvae that develop in dead broad-leaf trees. In laboratory bioassays, females were attracted to males, which suggested that males produce a sex pheromone. The congeneric species R. alpina is native to Europe, and another congener, R. funebris, is distributed in North America. The pheromone components produced by males of these species had been previously identified as two compounds from different biosynthetic pathways. In the present study, volatiles were collected from beetles of both sexes, and the analyses of the resulting extracts revealed a single male-specific compound, which was identified as 3,5-dimethyl-6-(1-methylbutyl)-pyran-2-one; this is the same compound as the pheromone of the European R. alpina. This alkylated pyrone structure is, so far, unique among known cerambycid pheromones. In field bioassays with traps baited with the racemic synthetic pheromone, significant numbers of both sexes of R. batesi were attracted in an approximately equal ratio, indicating that the compound is an aggregation-sex pheromone rather than a sex pheromone.

Mating Behavior of Rosalia batesi (Coleoptera: Cerambycidae) Is Mediated by Male-Produced Sex Pheromones.

Rosalia batesi Harold (Cerambycidae) is a hardwood boring species endemic to Japan. We investigated the adult mating behavior of this species in the field and laboratory. Most males appeared on mating sites before noon, significantly earlier than females did, in field observations. The female approached and contacted the male; the male responded and started the successive mating sequence, comprising mounting, copulation, and appeasement behavior. Before the encounter, the male raised its fore and mid legs and bent the abdominal tip ventrally. Next, a peculiarly structured bifurcate tip was exposed with opening and closing motion, which can be observed in the entire family Cerambycidae and is thought to be associated with the emission of volatile male sex pheromones. Male and female orientation toward conspecifics was examined using T-shaped olfactometers in four combinations (male⁻male, female⁻male, female⁻female, male⁻female). Males exclusively attracted females, indicating the existence of male-produced sex pheromones. A laboratory bioassay with three temperature regimes revealed the temperature dependence of this calling behavior. The calling behavior occurred only when the air temperature and male body surface temperature, which are associated with light intensity, were within the range of 26⁻33 °C and 26⁻28 °C, respectively.

Identification of a male-produced sex-aggregation pheromone for a highly invasive cerambycid beetle, Aromia bungii.

The longhorned beetle Aromia bungii (Coleoptera: Cerambycidae) is a major pest of stone fruit trees in the genus Prunus, including cherries, apricots, and peaches. Its native range includes China, Korea, Mongolia, and eastern Russia, but it has recently invaded and become established in several countries in Europe, and Japan, and it has been intercepted in shipments coming into North America and Australia. Here, we report the identification of its male-produced aggregation pheromone as the novel compound (E)-2-cis-6,7-epoxynonenal. In field trials in its native range in China, and in recently invaded areas of Japan, the pheromone attracted both sexes of the beetle. Thus, the pheromone should find immediate use in worldwide quarantine surveillance efforts to detect the beetle in incoming shipments. The pheromone will also be a crucial tool in ongoing efforts to eradicate the beetle from regions of the world that it has already invaded.