Resource profitability, but not caffeine, affects individual and collective foraging in the stingless bee Plebeia droryana

Author(s)

Peng, Tianfei ^[1] ; Segers, Francisca H. I. D. ^[2] ; Nascimento, Fabio ^[3] ; Grueter, Christoph ^[1]

Affiliation

^[1] Johannes Gutenberg Univ Mainz, Inst Organism & Mol Evolutionary Biol, D-55128 Mainz - Germany

^[2] Goethe Univ, Inst Cell Biol & Neurosci, Dept Appl Bioinformat, D-60438 Frankfurt - Germany

^[3] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, BR-3900 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: Journal of Experimental Biology; v. 222, n. 10 MAY 2019.
• Web of Science Citations: 1

Abstract

Plants and pollinators form beneficial relationships, with plants offering resources in return for pollination services. Some plants, however, add compounds to nectar to manipulate pollinators. Caffeine is a secondary plant metabolite found in some nectars that affects foraging in pollinators. In honeybees, caffeine increases foraging and recruitment to mediocre food sources, which might benefit the plant, but potentially harms the colonies. For the largest group of social bees, the stingless bees, the effect of caffeine on foraging behaviour has not been tested yet, despite their importance for tropical ecosystems. More generally, recruitment and foraging dynamics are not well understood in most species. We examined whether caffeine affects the foraging behaviour of the stingless bee Plebeia droryana, which frequently visits plants that produce caffeinated nectar and pollen. We trained bees to food sources containing field-realistic concentrations of sugar and caffeine. Caffeine did not cause P. droryana to increase foraging frequency and persistence. We observed P. droryana recruiting to food sources; however, this behaviour was also not affected by caffeine. Instead we found that higher sugar concentrations caused bees to increase foraging effort. Thus, unlike in other pollinators, foraging behaviour in this stingless bee is not affected by caffeine. As the Brazilian P. droryana population that we tested has been exposed to coffee over evolutionary time periods, our results raise the possibility that it may have evolved a tolerance towards this central nervous system stimulant. Alternatively, stingless bees may show physiological responses to caffeine that differ from those of other bee groups. (AU)

• FAPESP's process: 18/01266-8 - Does caffeinated forage affect foraging and recruitment in neotropical stingless bees?
• Grantee: Fábio Santos do Nascimento
• Support Opportunities: Research Grants - Visiting Researcher Grant - International