Study on synthetic acaricides and Nosema ceranae as drivers of pheromone and cuticular hydrocarbon alterations in honey bees.

PORRINI M. P.; GARRIDO P, M.; UMPIERREZ, M.L.; PORRINI L. P.; CUNIOLO A.; DAVYT, B; GONZALEZ ANDRES; EGUARAS M, J.; ROSSINI C.

Guarujá

Congreso; XVIIIth Congress of International Union for the Study of Social Insects (IUSSI); 2018

International Union for the Study of Social Insects

Homeostasis in honey bee colonies depend largely on semiochemicals which are social keyregulators in Apis mellifera. Exotic and natural pathogens, agricultural and veterinarytreatments pesticides introduced in the colony environment contaminate bees and hiveproducts. However, studies of the effects of this residuals on honeybee pheromones arescarce. In-hive acaricides and the gut parasite, Nosema ceranae, may alter differentsemiochemicals such as cuticular hydrocarbons (CHC), which are involved in socialrecognition and ethyl oleate (EO) which plays a role as primer pheromone in honeybees. Herewe test the effect of four acaricides, commonly applied to treat varroosis, on survival, rate offood consumption, CHC and EO on Nosema ceranae-infected and uninfected bees. Differentsublethal concentrations of amitraz, coumaphos, fluvalinate and flumethrin were administeredin syrup. Whole-body extracts were analyzed by GCMS. Quantification was conducted usingarachidic acid methyl ester and tridecane as internal standard for EO and normalizing the totalarea in the case of CHC. Nosema ceranae infection showed to decrease EO productionaffecting also survival rates, meanwhile acaricides, showed no significant effect. No synergiceffect was found in infected bees that received coumaphos. As for the CHC, we found nochanges in relation to the health status or consumption of acaricides, indicating absence ofalteration on communication and social recognition cues. It cannot be ruled out that theconcentrations here tested may have been not enough to trigger some effects, therefore,further experiments including higher doses and the study of the combined effect of two or more acaricides could yield different results. Nevertheless, beyond differences found with previousworks, having determined significant alterations in EO production as a response to N. ceranaeinfection is an interesting clue to deeper understand the effects of the disease on colonyfunctioning.