A Meta-Analysis Shows That Screen Bottom Boards Can Significantly Reduce Varroa destructor Population
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Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou 510260, China
2
Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
3
College of Animal Science (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou 350002, China
4
Yunnan Academy of Biodiversity, Southwest Forestry University, Kunming 650224, China
*
Author to whom correspondence should be addressed.
Insects 2020, 11(9), 624; https://doi.org/10.3390/insects11090624
Submission received: 22 July 2020
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Revised: 2 September 2020
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Accepted: 8 September 2020
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Published: 11 September 2020
Simple Summary
Varroa destructor is the most serious threat to the western honey bee, Apis mellifera. Screen bottom board, a cultural method for mite control, is a modified bottom board with a screen to allow mites to fall to a sticky board or to the grass or soil directly below the screen. Most studies show a trend of lower varroa population in colonies with these boards, but the results are usually not statistically significant. To understand whether the negative results were due to small sample sizes, or because the board is actually ineffective, we conducted a meta-analysis with seven published studies with 145 colonies. The results showed that the varroa population in colonies with screen bottom boards is significantly lower compared to those with traditional, wooden floors. The screen bottom board does have a significantly negative impact on the varroa population and can be part of tool kits for mite control.
Abstract
Varroa destructor is by far the most serious threat to the western honey bee, Apis mellifera. A screen bottom board, a cultural method for mite control, is a modified bottom board with a screen that allows mites to fall onto a sticky board, or the grass or soil below the screen. Whether or not a screen bottom board can reduce varroa significantly has been controversial. Most studies show a trend of lower varroa populations in colonies with these boards, but the results are usually not statistically significant. To understand whether the negative results have been due to small sample sizes, or because the board is actually ineffective, we conducted a meta-analysis with seven published studies with a total of 145 colonies. Meta-analysis showed that the confidence intervals of the combined effect sizes were negative with a Hedges’ g of −1.09 (SE 0.39, 95% CI −2.0 to −0.19, p < 0.01), which suggests that the varroa population in colonies with screen bottom boards is significantly lower compared to those with traditional wooden floors. We thus conclude that the screen bottom board does have a significantly negative impact on the varroa population and can be part of tool kits for mite control.
Keywords:
screen bottom board; wooden floor; Varroa destructor; honeybee
