Fig. 3. Clothianidin effect on DWV infection level and Varroa reproduction.

Asterisks denote significantly different mean values (one asterisk: P < 0.05; three asterisks: P < 0.001). a DWV infection level in honey bees eclosed from larvae reared in vitro on a diet with or without Clothianidin (the experiment was run in triplicate, for a total of 28 and 27 individuals for Clothianidin treated and untreated controls, respectively; the horizontal bars represent the sample average; Mann–Whitney U test: n₁ = 28, n₂ = 27, U = 140, one tailed P < 0.001). b Fertility of Varroa mites on honey bee larvae treated with Clothianidin or on untreated controls (the experiment was run in triplicate, for a total of 111 and 120 individuals for Clothianidin treated and untreated controls, respectively; the proportion of reproducing mites in each replicate along with the average fertility and relative standard deviation are reported; Mantel–Haenszel test: df = 2, M–H Chi-2 = 3.970, P = 0.046).