Effect of the varroacide Eupatorium buniifolium, (Asteraceae) essential oil, on survival and pheromone production in healthy honeybees.

RODRIGO, F; DAVYT, B; UMPIERREZ, M.L.; GONZALEZ, A.; GARRIDO P. M.; PORRINI M. P.; EGUARAS, M. J.; DOMINGUEZ, E.; DAMIANI, N.; GENDE L, B.; ROSSINI C.

Valparaíso

Congreso; 5th Congress of the Latin American Association of Chemical Ecology; 2018

Latin American Association of Chemical Ecology

The essential oil from Eupatorium buniifolium (EOEb) has fumigant activity againstVarroa destructor (Mesostigmata: Varroidae), the ectoparasite that contributes to thehoneybee colony collapse disorder and is innocuous to honeybees. These previousobservations prompted us to investigate the effect of the ingestion of the EOEb in larvaand adult survival and in adult pheromone production. In larvae, the survival after EOEbingestion at different doses (100 to 1000 ppm) showed no significant differences betweentreatments and controls (Survival analysis, Wilcoxon Nonparametric DistributionAnalysis, P = 0.657). In adults, the EOEb was supplied in the diet for 12 days to 2-dayold honeybees. Food consumption was not different among honeybees fed with the EOEbat different doses (300 to 6000 ppm) and the control honeybees (ANOVA, p < 0.01);neither was the survival among groups (Survival Analysis Kaplan-Mayer, P > 0.05).Ethyl oleate (EO) is a primer pheromone that regulates the worker behavioral changesand that has been reported to change under stress conditions. The cuticular hydrocarbons(CHC) act also as a pheromone involved in social recognition. At the end of the assay,both pheromones were quantified by GCMS. Honeybees that had consumed the EOEbexhibited similar titers of EO as control honeybees (ANOVA, GLM, P> 0.05). However,when comparing honey bees fed on the EOEb diet to the control ones, CHC differences(ANOVA, GLM, Tukey post-hoc pairwise comparisons, at the higher doses tested) werefound for linear alkanes (p = 0.019), branched alkanes (p = 0.012) and alkenes (p = 0.01).However, up to 3000 ppm of ingested EOEb, either of the CHC groups showed nodifferences compared to the control bees.These results point to the E. buniifolium essential oil as a good candidate to develop abotanical acaricide in doses lower than 3000 ppm.