Live Varroa jacobsoni (Mesostigmata: Varroidae) fallen from honey bee (Hymenoptera: Apidae) colonies.
Webster TC, Thacker EM, Vorisek FE.
J Econ Entomol. 2000 Dec;93(6):1596-601.
Source: Community Research Service, Kentucky State University, Frankfort 40601, USA.
Abstract: The proportion of Varroa jacobsoni Oudemans that were alive and mobile when they fell from honey bees, Apis mellifera L., in hives was measured during a 20-wk period to determine the potential use of systems that prevent these mites from returning to the bees. Traps designed to discriminate between the live, fallen mites and those that are dead or immobile were used on hive bottom boards. A large fraction of the fallen mites was alive when acaricide was not in use and also when fluvalinate or coumaphos treatments were in the hives. The live proportion of mitefall increased during very hot weather. The proportion of mitefall that was alive was higher at the rear and sides of the hive compared with that falling from center frames near the hive entrance. More sclerotized than callow mites were alive when they fell. A screen-covered trap that covers the entire hive bottom board requires a sticky barrier to retain all live mites. This trap or another method that prevents fallen, viable mites from returning to the hive is recommended as a part of an integrated control program. It also may slow the development of acaricide resistance in V. jacobsoni and allow the substitution of less hazardous chemicals for the acaricides currently in use.
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The question arises: how sticky is sticky? I am not seeing any signs of life in the varroa on my drop boards, even with magnification, and initially, I used boards with no grease, and have now been using a thin layer of Vaseline applied with a wide putty knife, then run over with a roller to roller to raise some texture.
I might add that I am now thinking that I overestimated the mite load, judging by the response to the oxalic fog.
Also, I am still trying to come to grips with Randy's earlier comment:
"In a natural drop, if brood is present, about half of the mites that drop
"are ones coming out of emerging brood, that (Lobb 1997 Mortality of Varroa jacobsoni
"Oudemans during or soon after the emergence of worker and drone
"honeybees, Apidologie 28:367).
Of particular interest is the statement, "would not survive for more than a few hours". Does this apply to young adults, or immatures.
I am detailing my thinking and literature search at http://www.honeybeeworld.com/diary on an ongoing basis.
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