Data from: The reluctant mutualist: toxic nectar can reduce olfactory memory in Asian honey bees

The nectar of the thunder god vine, Tripterygium hypoglaucum, contains a terpenoid, triptolide (TRP), that is toxic to the sympatric Asian honey bee, Apis cerana. However, these bees will forage on, recruit for, and pollinate this plant during a seasonal dearth of preferred food sources. Olfactory learning plays a key role in forager constancy and pollination, and we therefore tested the effects of acute and chronic TRP feeding on forager olfactory learning, using proboscis extension reflex conditioning. At a concentration of 0.5ug TRP/ml, within the natural range, there were no learning effects. However, memory retention (1 h after the last learning trial) significantly decreased by 56% following acute consumption of 0.5 ug TRP/ml. Chronic exposure did not alter learning or memory, except at high concentrations (5 and 10 ug TRP/ml) that are likely not biologically relevant. Natural TRP concentrations in nectar should therefore not significantly harm plant pollination. Long term exposure to TRP could have colony effects, but these may be ameliorated by the bees aversion to T. hypoglaucum nectar when other food sources are available and, perhaps, by detoxification mechanisms. The co-evolution of this plant and its reluctant mutualist may therefore illustrate a classic compromise between the interests of both actors.