Glass arena used in the bioassays.

<p>A 6 cm diameter glass Petri dish was placed upside down in a larger Petri dish containing a wet piece of filter paper (light grey). Two concentric circles were drawn on the inner surface of the Petri dish, having 1 cm radius (start line or line A) and 2 cm radius (finish line or line B). The treatment was applied with a pipette outside the finish line (dark grey) on the outer surface of the Petri dish in 100 µl volume of solvent. After the complete evaporation of the solvent, a single nymph was placed with a fine paint brush in the center of the arena and the time spent to go from line A over line B was recorded. The dashed line represents the track captured from the video of a single tick moving on an arena treated with a repellent substance (in this case 100 µg of eugenol).</p

Repellency and vapor pressure (listed in descending order) of each tested compound.

<p>Grey tones indicate the repellency of each molecule: dark grey represents molecules that are repellent at the lowest dose (10 µg); medium grey, molecules repellent at the medium dose (100 µg); light grey, molecules repellent only at the highest dose (1000 µg); very light grey, molecules which are not repellent even at the highest dose. Predicted vapor pressure values (mmHg) at 25°C are from: ACD/Labs Predicted Properties (In: ChemSpider website. URL: <<a href="http://www.chemspider.com" target="_blank">http://www.chemspider.com</a>>, accessed 21Jan 2010).</p

List of the substances considered in this study.

<p>List of the substances considered in this study.</p

Gene expression analysis of mite-infested pupae and adult bees.

Relative expression of the immune-related genes Apidaecin (a), Defensin-1 (b), Dorsal-1A (c) and of the RNAi related genes Argonaute-2 (d) and Dicer-like (e) of pupae and adult bees challenged with V. destructor. (Two-way ANOVA test. Apidaecin: mite: df = 1, F = 0.192, p = 0.66; age: df = 1, F = 1.179, p = 0.29; mite*age: df = 1, F = 1.237, p = 0.28; Defensin-1: mite: df = 1, F = 9.680, p df = 1, F = 294.82, p df = 1; F = 0.185, p = 0.67; Dorsal-1A: mite: df = 1, F = 2.156, p = 0.15; age: df = 1, F = 37.624, p 0.01; df = 1, F = 3.058, p = 0.09).; Ago-2: mite: df = 1, F = 2.99, p = 0.09; age: df = 1, F = 0.09, p = 0.75; mite*age: df = 1, F = 1.07, p = 0.31,; Dicer-like: mite: df = 1, F = 1.90, p = 0.18; age: df = 1, F = 5.23, p = 0.03; mite*age: df = 1, F = 0.93, p = 0.34. Uninfested pupae: n = 6, mite-infested pupae: n = 6, uninfested adults: n = 6, mite-infested adults: n = 5).</p

DWV infection in honey bees mite-infested during the pupal stage.

DWV relative quantification obtained by real time PCR in newly emerged honey bees infested or not with one mite at the L5 stage (Mann-Whitney U test. U = 22, df = 1, p = 0.02, uninfested bees: n = 10, mite-infested bees: n = 10).</p

Survival of the honey bees DWV-infected during the pupal stage.

Survival curves of adult honey bees infected or not with 10^3 DWV copies at the larval stage and maintained under lab conditions (Wilcoxon test. Chi square = 6.42, df = 1, p = 0.01, uninfected bees: n = 52, DWV-infected bees: n = 50).</p

DWV genotypes.

Percentage of viral reads mapping on the two genomes, type A and B DWV.</p

Survival of honey bees mite-infested during the pupal stage.

Survival curves of the adult bees artificially infested or not with one Varroa mite at the L5 stage and maintained under lab conditions (Wilcoxon test. Chi square = 6.4; df = 1; p < 0.01, uninfested bees: n = 103, mite-infested bees: n = 76).</p

Survival of the honey bees DWV-infected at the adult stage.

Survival curves of the adult honey bees infected or not with 10^3 DWV copies after the emergence (Wilcoxon test. Chi square = 22.29, df = 1, p < 0.01, uninfected bees: n = 99, DWV-infected bees: n = 98).</p

Effects of the infestation’s time on bees’ survival.

Survival curves of the adult bees uninfested and artificially infested with one Varroa mite at the L5 stage or at the emergence and maintained under lab condition (Wilcoxon test. Infestation at larval stage vs control: chi square = 52.3, df = 1, p df = 1, p df = 1, p = 0.05, uninfested bees: n = 164, bees mite-infested at the larval stage: n = 140, bees mite-infested at the adult stage: n = 121).</p