As of June 1999, the beetle has been found in Georgia, North and South Carolina, Florida, Minnesota, Ohio, Pennsylvania and New Jersey in the United States. Although first described in Florida, it is thought the beetle was originally introduced in the coastal portions of South Carolina or Georgia and then transported in bee colonies to Florida. Introduction into other states has principally been through package bees from South Carolina and Georgia. Whether the beetle can persist in temperate regions of the United States and how far it will spread is only conjecture at the present time.
Eggs: Eggs of Aethina tumida are pearly-white, 1.4 m.m. long by 0.26 m.m. wide, similar in appearance to honey bee eggs, but smaller, being approximately two-thirds the length of the latter. Eggs are deposited in irregular masses. The female appears to prefer some crevice or cavity. Comb is not required and often ignored when females lay eggs as they can be found anywhere within the hive. Incubation period varies from one to six days, with most hatching between two to four days. The number of eggs a single female can lay has not been determined, however, Lundie has shown that two or three beetles in a pile of supers can cause a heavy infestation. Females are also relatively long-lived (ranging from a few days to several months) which adds to their egg-laying capacity.
Larvae: The larva of the small hive beetle is the damaging stage of this pest. Larvae emerge from the egg shell through a longitudinal slit. Newly-emerged larvae have relatively large heads and numerous protuberances all over their bodies. This may protect them from being smothered in honey. Beetle larvae may be confused with those of the greater wax moth Galleria melonella), however, they can easily be distinguished by the presence of six prominent anterior legs. Wax moth larvae have a number of smaller less-developed, uniform prolegs. Both organisms may be found simultaneously in the same colony.
There is great variation in growth rate of same-aged larvae Generally it is 10 to 14 days, but may be a week or longer. Slower maturing larvae are smaller and give rise to small adults. Many die soon after pupation, whereas mortality is less in quicker maturing individuals. Larvae grow to 3/16 to 1/4 inch by day four, reaching 7/16 inch with a 1/16 inch diameter when full grown. Larvae entering the soil make a smooth-walled earthen cell to pupate. In damp soil, these may be connected by a tunnel to the surface and larvae may return to the surface before pupating. It is during transition from larva to pupa that the insect is vulnerable. The nature of the soil is also thought to be a variable in successful development.
Pupae: Pearly white color predominates in newly formed pupae. Pigmentation begins with transformation to adult, first in the eyes and then wing base before encompassing the whole body. Frequent twitching of legs is observed as maturing occurs within the pupal skin. Period spent in the soil varies greatly from 15 to 60 days. The majority of beetles emerge after three to four weeks in the ground.
Adults: The newly-matured adult is light, yellowish brown and becomes brown, dark brown and finally black at full maturity. This changes take place during pupation and brown or black adults may be seen emerging from the ground. During the first day or two after emergence, young beetles are active, take flight readily and orient toward light. Later they become less active and keep to less illuminated portions of the bee colony. Adults are covered with fine hair, which makes them difficult to pick up by hand.
larvae, with adult and worker bees
Females begin to lay eggs about a week after emergence. Adults show great size variablility, but most are approximately 3/16 inch long and 2/3 broad as long. They are about one-third the size of a honey bee worker.Longevity appears to be evenly distributed across ages, ranging from only a few days to six months. Forty of sixty-eight individuals in Dr. Lundie's study lived over two months. Longevity and overlapping of generations makes the beetle a constant source of annoyance to beekeepers.
Although wax moth larvae eat comb enriched by honey bee pupal skins, beetle larvae eat live brood and honey. Worse, they defecate in the honey promoting fermentation. Fermenting odor may be the first sign of a beetle-infestation. Fermentation is associated with many of the beetles in the family Nitidulidae. Frothy, fermented honey produced by the larvae is abandoned by the bees. Infestation of honey filled supers can happen very quickly. It appears beetles may lay eggs when supers are removed. Thus, larvae can hatch when no adult honey bees are present. Largest infestations have been found in and near honey houses. Unlike wax moth larvae, those of the small hive beetle do not appear to destroy the comb. Thus, fermented honey can be washed off infested combs, particularly those reinforced by generations of pupal honey bee skins, and they will be reused by bees.
Chemical control of beetles is problematic because no action thresholds have been defined. There are two routes to control: 1) in the colony and 2) soil treatment for developing pupae. A Section 18 special exemption for Bayer Bee Strips (CheckMite +) has been authorized by the Environmental Protection Agency (EPA). This is formulated using the active ingredient coumphos (10%), an organophosphate pesticide impregnated in a plastic strip. Honey supers must be removed before applying this material as a plastic strip stapled onto cardboard inserts. In Florida, it must also be used in accordance with a label and two separate memoranda written to the Florida Department of Agriculture and Consumer Services by EPA dated January 6 and May 28, 1999. The latter increases the treatment window from seven to 45 days and increases the number of strips that can be sold in Florida to 700,000. All the documents must be in the hands of applicator at time of application. For more specific information, contact a beekeeping supply outlet.
A product called GardStar® (40% EC) has also been labeled for treating small hive beetle in the soil. It is formulated as an emulsifiable concentrate containing 40% permethrin. It can be used any time of year and applied by low-pressure spray equipment. The product is packaged in 4 fl. oz. bottles with a 15-mil self-dispensing chamber for easy mixing. Again, it must be used in accordance with the label and can be found in many garden and pest control stores.
This is good advice; it already is common beekeeping practice in both Africa and Florida. The bees in Africa, however, are different than those in most of North America. Apis mellifera scutellata, the African honey bee, has radically different behavior from that found in the European Apis mellifera bee, managed by the beekeepers of North America. It is already known that African bees in the face of light predation or perturbation readily abscond. In doing so, they leave behind a nest heavily infested with all kinds of possible organisms. Dr. Lundie suggests that this behavior may be a reason why American foulbrood has never taken hold in South Africa. Scavengers like wax moths and A. tumida remove abandoned nests so quickly that the disease reservoir ceases to exist. European honey bees are not as likely to abscond as African bees; they also may not be as hygienic in the nest. Both are reasons that their relatives Africanized bees are thought to be more tolerant of the varroa mite.
Another African honey bee, Apis mellifera capensis, is also affected by the beetle, but appears also to be withstanding its effects. What does inferior hygienic behavior and the lack of a tendency to abscond portend for North American bee colonies invaded by A. tumida? Dr. Lundie provides a hint of this in his publication, saying that when honey bees cannot eject the beetle easily, strong as well as weak colonies may be equally affected. In addition, even in South Africa, at rare times the beetle can heavily affect colonies.
A. tumida is at its most vulnerable when the larvae leave the hive to pupate in the soil, and this probably represents a good starting point for beekeepers to experiment with controlling this insect by cultural means. Perhaps the larvae can be trapped somehow before they reach the soil. Soil conditions also become important; the larvae may not pupate effectively in too dry, sandy or wet conditions. Dr. Lundie reports some indications that larvae infested with a soil-dwelling fungus died. Certain ants or other insects may prey on the larvae. The imported fire ant (Solenopsis invicta) in the southern United States comes to mind as a possibility in some areas.
Dr. Lundie reports that stationary colonies are more vulnerable than those that are moved. Thus, relocating colonies may break the beetle's life cycle, a classic control measure used elsewhere in agriculture. Certainly the bees' self-cleaning behavior itself should be used to the utmost. Colonies will probably vary in the ability to withstand infestation and should be monitored for the ability to do so. As part of this, beekeepers should be very careful not to provide more exposed comb than the bees can adequately cover, or purposefully infest a colony that doesn't already have beetles. The beetle's arrival could signal a paradigm shift in honey bee management. Standard practices like stacking empty or weak colonies on stronger ones, making weak splits, and/or liberally exchanging combs are not good options in beetle control.
Beekeepers should constantly monitor their operations for presence of the beetle. Detection is relatively easy. The larvae can be examined for the six rather large legs on their front end; wax moth larvae have uniformly sized prolegs found in most lepidopterous larvae. In contrast to those of the beetle, wax moth larvae do not usually move toward light, leave a colony nor burrow into the soil. Adult beetles are easy to spot, uniform in color and about one-third the size of an adult worker bee. They rapidly run across the combs and can often be found hiding in places that are not accessible to larger-bodied honey bees. Until more is known about the beetle in a particular area, it should be assumed that it is far more aggressive a scavenger than the wax moth and may overwhelm even strong, healthy colonies.
If A. tumida is suspected or detected, the following precautions are suggested:
Other tidbits of information have been obtained through observation of beetle behavior:
Author: Malcolm T. Sanford, University of Florida
Photographs: M.T. Sanford, University of Florida; and Division of Plant Industry
Project Coordinator: Thomas R. Fasulo,
University of Florida
Publication Number: EENY-94
Publication Date: June 1999. Latest revision: September 2005.
Copyright 1999-2005 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
larva
dorsal view
ventral view
beetle larvae
larvae in honey