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Invisible to the naked eye, these mites have white oval bodies with several long fine hairs. The mouth-parts are beak-like and elongated. Females are 143-147 microns long and 77-81 microns wide with mane being 125-136 microns long and 60-70 microns wide. There are not very many apparent symptoms present in an infected bee until the infestation is severe. The bees may develop disjointed and unable to fly. Honey production may decline. The only way to verify is to dissect the dead bees and examine the tracheae, which will be brown in color instead of white like in healthy bees.
Mites move quickly through a colony via bee-to-bee contact within the hive. Workers and drones drifting from hive to hive disperse the mite from one apiary to another. Bees also encounter mites when they rob honey from other hives; and colonies weakened from heavy mite infested are very prone to being robbed. When this mite was initially discovered in the United States it caused severe destruction of honeybee hives all over and was especially severe in the more temperate parts of the country. Acarapis woodi kills by clogging the breathing tubes of the bees and the normally elastic trachea becomes brittle and stiff, and flight muscles atrophy. The effects of a mite infestation can remain in a colony for years with little damage, making them not as severe as it was in the 1980s and 1990s.
Tracheal mites puncture the walls of the breathing tubes and feed on the hemolymph (blood) of worker, drone and queen bees. The female mite enters the bees shortly after it emerges from its cell by moving through the thoracic air duct into the trachea, where she remains until the bee dies. Three to four days after arrival she lays about 6 eggs, which hatch in another three to four days. After the eggs have been laid, adult male mites are mature in 11-12 days and females in mature 14-15 days. Once they mature females with eggs “jump” to a new host to then continue the cycle. Mite infections tend to be cyclical; they are worse during the winter when the bees are confined and decline in the summer.
Acarapis woodi was unknown in the United States until 1980, when it was found in Mexico only 200 miles south of the Texas border. In early July 1984 it was found at a commercial beekeeping enterprise in Weslaco, Texas; the following month they were found in Louisiana and by October 1984 they were reported in Florida, Nebraska, New York, North Dakota and South Dakota. The rapid spread of the mite was facilitated by migratory beekeepers whose truck bees from the southern states northward to pollinate various crops.
U.S. Present: All states except Alaska
U.S. Habitat: Tracheal tubes of the European honey bees, Africanized honey bees and Asian honey bees
Chemical control may involve fumigation with menthol crystals. Grease patties, made of vegetable shortening and sugar are commercially available and keep mites from infesting young bees because the oily bees do not “smell” right to the mites. Evaporating formic acid is also very effective in controlling tracheal mites and has the added bonus of reducing varroa mite infestations.
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Gary, N. E., Page Jr, R. E., & Lorenzen, K. 1989. Effect of age of worker honey bees (Apis mellifera) on tracheal mite (Acarapis woodi) infestation. Experimental & applied acarology, 7(2), 153-160.
Hoppe, H., Ritter, W., & Stephen, E. W. C. 1989. The control of parasitic bee mites: Varroa jacobsoni, Acarapis woodi and Tropilaelaps clareae with formic acid. American bee journal, 129.
Otis, G. W., & Scott-dupree, C. D. 1992. Effects of Acarapis woodi on overwintered colonies of honey bees (Hymenoptera: Apidae) in New York. Journal of economic entomology, 85(1), 40-46.
Pettis, J. S. and W. T. Wilson. 1996. Life History of the honey bee tracheal mite (Acari: Tarsonemidae). Annals of the Entomological Society of America. 89:368-374.
Sammataro, D., Gerson, U., & Needham, G. 2000. Parasitic mites of honey bees: life history, implications, and impact. Annual review of entomology, 45(1):519-548.