The ant´s weapon improve honey bee learning performance

Introduction Formic acid is the main component of the ant’s major weapon against enemies. The repelling effect of the organic acid is used by some mammals and birds which rub themselves in the acid to eliminate ectoparasites. Beekeepers rely on this effect to control the parasitic mite Varroa destructor. Varroa mites are considered the most destructive pest of honey bees worldwide and can lead to the loss of entire colonies. Formic acid is highly effective. Whether formic acid can also affect the behavior of honey bees is unknown.

Material and Methods In the present work the influence of a formic acid treatment on sucrose responsiveness and cognition of the honey bees has been investigated. Classical olfactory conditioning using the proboscis extension response (PER) was employed to quantify learning and memory abilities. Sucrose responsiveness was tested prior to training using the PER to increasing concentrations to sucrose. In our study, bees of different developmental stages were treated with 60% formic acid for two weeks. All bees were trained at adult age.

Results Treatment with formic acid did not affect sucrose responsiveness in foragers. Responsiveness generally increased with increasing sucrose concentrations. This was independent of whether bees had experienced formic acid or not. Treatment duration had a small but significant effect on sucrose responsiveness in young hive bees but not in foragers.

Formic acid significantly improved learning of the CS+ of both foragers and young hive bees.

Conclusion Honey bees exposed to formic acid learn significantly better than untreated controls. We therefore expect a positive effect on foraging efficiency in colonies treated with formic acid, since learning is an integral part of central place foraging performed by honey bees. Ultimately, a higher efficiency of honey bee foragers whose colony had been treated with formic acid might compensate for the loss of worker bees resulting from high brood mortality during treatment.

Publication History

Article published online:
13 November 2023