Only three scarab beetles of the genus Osmoderma live in North America. This beetle, O. eremicola, is on average larger than its relative, O. scabra, the Rough Flower Beetle (also in this area). It is fairly similar to O. subplanata, however, this is a western beetle not present in this region.
These beetles derive their name, Osmoderma, meaning “smelly skin” from their European counterpart, O. eremita, the Russian Leather Beetle. That beetle releases a scent detectable from several meters away, thought to be a type of pheromone.
These beetles can exceed 2-2.5 cm. They have large, shiny shells varying from black to deep brown; the elytra is almost smooth with slight lines and texture.. They also have short, fine brown hair on the lower abdomen and at the rim of the elytra. They have a distinct excavation on the front of their thorax (middle body segment) and another between their eyes. The larvae are large, white grubs with a hard, reddish head. They can reach 4-5 cm.
These beetles are nocturnal, and reside in the daytime near the bases of trees. They feed on sap and occasionally fruit. The larvae reside in decaying wood, often in apple or cherry trees. The larvae take three years to reach maturity, and are freeze resistant in the winter. In the late autumn of their third year, they pupate in oval cells formed from fragments of wood, cemented with a waterproof, glutinous secretion. The following autumn, often in July through September, they emerge as fully grown beetles. Following this, they mate and lay eggs, which develop into larvae.
This specimen was discovered on Tuesday night by the beetle crew on the Brodies’ carpet. What it was doing there is a mystery.
Article by Hazel Galloway