Small hive beetles ( Aethina tumida) are an invasive species native to sub-Saharan Africa, where they are minor scavengers in honey bee colonies. Outside their native range, these beetles have become a significant global pest for beekeeping. First detected in the United States in 1996, they have since spread to numerous regions, including North America, Australia, and parts of Europe, causing considerable economic losses for beekeepers.
Identifying Small Hive Beetles
Adult small hive beetles are oval-shaped, measuring about 5-7 mm long and 3-4.5 mm wide, one-third the size of a worker bee. Their color ranges from reddish-brown when newly emerged to dark brown or black as they mature. They possess distinctive club-shaped antennae and have wing covers that are shorter than their abdomen, exposing the last abdominal segment.
When disturbed, these beetles can move very quickly and hide in dark, tight spaces, such as under the inner cover or on the bottom board. Small hive beetle larvae are creamy-white grubs, about 10-11 mm long, with a brown or tan head. They have three pairs of jointed legs located near their head and two rows of small spines along their back, which helps distinguish them from wax moth larvae that have many small, uniform legs along their body.
Life Cycle and Hive Damage
The small hive beetle undergoes a complete metamorphosis with four stages: egg, larva, pupa, and adult. Female beetles lay irregular clusters of eggs in hive crevices or directly on comb, with a single female capable of laying 1,000 to 2,000 eggs in her lifetime. Eggs hatch within 1 to 6 days, influenced by humidity and temperature.
The larval stage is the most destructive, as larvae burrow through honeycombs, consuming honey, pollen, and bee brood. While feeding, larvae defecate in the honey, introducing a yeast species (Kodamaea ohmeri) that causes the honey to ferment, froth, and weep from the cells. This spoilage renders the honey inedible to bees and unmarketable to humans. After 6-14 days, mature larvae leave the hive and burrow into the soil to pupate. Pupation can take 2-12 weeks, with moist, warm soil favorable for adult beetle emergence.
Recognizing an Infestation
Observing specific signs during a hive inspection can indicate a small hive beetle infestation. Adult beetles may be seen quickly scurrying across combs or hiding in dark, tight spaces. Larvae are often visible tunneling through the comb or congregating in corners of frames or on the bottom board.
A strong indicator of an infestation is the presence of slime trails or fermented honey, which may have a distinct odor resembling rotting oranges. The honey might bubble out of cells or pool on the hive floor. In severe cases, the queen may stop laying eggs, the adult bee population might decline rapidly, and the colony may abscond, leaving behind a heavily damaged hive.
Managing Small Hive Beetle Populations
Effective management of small hive beetle populations involves a combination of preventative measures and active control strategies. Maintaining strong, healthy colonies with a high bee-to-comb ratio is a primary preventative step, as robust colonies are better equipped to defend against beetles and remove larvae. Minimizing cracks and crevices within the hive and keeping the bottom board clear of debris can reduce hiding and breeding sites for beetles. Proper apiary hygiene, such as promptly removing dead colonies, burr comb, and wax scraps, helps prevent attracting beetles to the area.
Various mechanical traps can be deployed inside the hive to control adult beetle populations. Many designs utilize small openings that allow beetles to enter but restrict bees, drowning the beetles in vegetable or mineral oil. Corrugated cardboard or plastic strips placed on the bottom board can also serve as hiding spots for beetles, which can then be removed and destroyed. While chemical treatments are available, their use within hives is limited due to potential contamination of honey products. External treatments, such as permethrin soil drenches, can target pupating larvae in the soil around the hive. Entomopathogenic nematodes around hives can also reduce beetle populations by targeting the larval and pupal stages in the soil.