Midnite Bee-Beekeeper's: Reports
The adults are broad, flattened beetles about 5-7 mm long and dark brown to nearly black in color. The adults can be distinguished from other U.S. nitidulids by the following suite of characters: eyes with tuft of setae laterally; legs broad and flattened; pygydium basally with a transverse row of foveae (It often necessitates removal of pygydium to observe this character.).
The larvae are elongate, whitish grubs which under magnification can be seen to have rows of spines on the dorsum. Adults and larvae inhabit beehives, where they feed on stored pollen and honey.
Larvae in corner of frame
A frame infested with Aethina tumida.
Combs are damaged and brood killed by the burrowing of the beetle larvae. As an infestation grows, the honey ferments, and bubbles out of the cells. The fermenting honey is said to have the odor of decaying oranges. Pupae are white to brown and are found in the soil beneath hives.
In South Africa, development from egg to adult required 38 to 81 days, with five generations a year possible during the warmer months. They have been shown to attack bumblebee nests in the laboratory, and have been observed to survive winters in the hive inside the bee cluster.