A paper titled "Quick Sex-Determination of the Asiatic Garden Beetle, Maladera formosae (Coleoptera: Scarabaeidae)" by Adrian Pekarcik, Scott Clem, Kyle Akred, and Kelley Tilmon was published November 2022 in The Great Lakes Entomologist. In this paper, authors identified a quick way to determine the sex of Asiatic garden beetle (AGB) adults. To successfully determine the sex of an AGB adult, one will need either a dissecting microscope - or even a hand lens in the field. Next, you need to look at the abdomen of the AGB and identify the pygidium, or last dorsal tergite. For a male AGB the pygidium touches the margin of the last abdominal sternite. In the female, it is parallel.
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Illustrations above by Suranga Basnagala.