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Description

Adult Description Adults are broad, flattened beetles about 5.7 mm (¼ inch) long, 3.2 mm wide and dark brown. Just after pupation the adults look red, but soon start turning darker as their exoskeleton hardens. These beetles are very swift, and agile among the honey bee hive combs, making them difficult to be caught.

Larvae Description: The larvae are elongate, whitish grubs with rows of small spines along the back. Larvae look superficially like wax moth larvae, but the legs of beetle larvae are larger, more pronounced, and restricted to near the head. Pupae are whitish brown.

Ecological Threat

In Africa this beetle behaves as a scavenger of weakened colonies, and it is considered only a secondary pest. This does not seem to be the case for the United States, especially in Florida, South Carolina and Georgia. In its initial discovery year of 1998, beekeepers in Florida alone lost over $3 million dollars due to damage by this beetle. The larvae tunnel through combs, killing bee broods and ruining combs. Bees in Florida have been found to abandon combs, and entire colonies once they are infested. Beetles defecate in honey and cause it to ferment, producing a frothy mess in honey houses. Honey thus contaminated is no longer salable, smells like rotting oranges, and moreover it is unpalatable to bees and cannot even be used as bee feed.

Biology

Beetle larvae do not spin webs or cocoons in the bee hive, they pupate in the soil outside the hive. In heavily-infested operations in Florida, larvae have been observed crawling out of colony entrances or across honey house floors in an effort to reach soil to dig in and complete their development. In southern Africa it requires 38-81 days to develop from egg to adult, and five generations per year are possible. Once the beetles emerge from pupation in the soil they search for new honey bee colonies to infest.

History

Aethina tumida was first discovered in the United States in 1998, in an apiary in Florida. The beetle has spread across the United States, and has been found in Texas since 2008. Researchers at TISI have been studying commercial honeybee hives for various internal and external hive parasites, and they have confirmed the presence of this beetle at several apiaries across several Texas ecoregions.

Native Origin

Sub- Saharan Africa

Current Location

U.S. Habitat: Anywhere domesticated and commercial European honey bee hives are.

U.S. Present: CA, CT, GA, FL, IL, MD, MI, MN, MO, NC, NJ, NY, OH, PA, RI, SC, TX and VA.

Management

Since its discovery in the United States, chemical control is not a popular method of control for these beetles in the apiary community. However, there are a couple of products available, including GuardStar™ which is applied on the ground to kill pupating beetles, and Checkmite+™ a plastic strip placed under pieces of cardboard in colonies to kill adult beetles. What has been prgorressing as a control method in the United States is a mechanical and cultural control. The factsheet on Bugwood.org provided good cultural and mechanical steps to take:

Be clean around the honey house. Do not leave filled supers standing long before extraction. Do not leave cappings exposed for long periods. Beetles can build up rapidly in stored honey, especially away from protective bees.
Do not stack or store infested supers onto strong colonies.
Be aware that supering colonies, making splits, exchanging combs, or use of Porter bee escapes can spread the beetles or provide room for beetles to become established away from the cluster of protective bees.
Monitor colonies for hygienic behavior; ie., the ability to actively rid themselves of both larval and adult A. tumida. Propagate those queen lines found to be beetle-resistant.
Experiment with trapping or cultural control measures. It may be possible to trap beetle larvae as they attempt to reach soil and pupate. Moving colonies may be advisable to keep a beetle population from building up in any particular apiary. The ability of beetles to complete development may vary according to different soil conditions and beekeepers may find some locations naturally less prone to beetle infestation. Fire ants may be a beneficial insect in this context if they are found to prey on pupating beetles.
Bees will normally not clean up equipment or supers full of beetle-fermented honey. However, bees may finish the job if the beekeeper first washes out as much honey as possible with a high-pressure water hose.

Research into biological controls for these beetles are continuing. Potential controls include the nematodes Steinernema riobrave and Heterorhabditis indica. Additionally, researchers have found that some honeybees are able to detect and remove the brood that has been oviposited on by small hive beetles. Through TISI’s ongoing honeybee sampling in Texas, personal comments from beekeepers have mentioned that with the proper materials (sometimes pieces of cotton) the bees will actually wrap up the adult beetles and remove them from the hive.

References

References

Caron, D.M. 1997. Other insects. In Honey bee pests, predators and diseases 3d ed. (R.A. Morse & K. Flottum eds.). A.I. Root Co., Medina, Ohio.

Ellis, JD, Hepburn, H.R. 2006. An ecological digest of the small hive beetle (Aethina tumida), a symbiont in honey bee colonies (Apis mellifera). Insectes Sociaux, 53(1): 8-19.

Elzen, P.J., J.R. Baxter, D. Westervelt, C. Randall, K.S. Delaplane, F.A. Eischen, L. Cuffs, & W.T. Wilson. 1999. Field control and biology studies of a new pest species, Aethina tumida Murray (Coleoptera: Nitidulidae), attacking European honey bees in the Western Hemisphere. Apidologie 30: 361-366.

Hood, WM 2004. The small hive beetle, Aethina tumida: A review. Bee World, 85(3): 51-59.

Neumann, P., & Ellis, J. D. (2008). The small hive beetle (Aethina tumida Murray, Coleoptera: Nitidulidae): distribution, biology and control of an invasive species. Journal of Apicultural Research, 47(3), 181-183.

Sanford, M.T. 1998. Aethina tumida: a new beehive pest in the western hemisphere. Apis 16(7), University of Florida

Internet Sources

http://bugwood.org/factsheets/small_hive_beetle.html

http://wiki.bugwood.org/Aethina_tumida

http://entnemdept.ufl.edu/creatures/misc/bees/small_hive_beetle.htm

http://nematology.ifas.ufl.edu/nguyen/morph/INDICUSI.htm