Floral Species Richness Correlates with Changes in the Nutritional Quality of Larval Diets in a Stingless Bee
Department of Animal Ecology and Tropical Biology, University of Würzburg, 97074 Würzburg, Germany
Department of Public Technology and Innovation Planning, Fraunhofer Institute for Technological Trend Analysis INT, 53879 Euskirchen, Germany
Environmental Futures Research Institute, Griffith University, Nathan Campus, QLD 4111, Australia
CSIRO Ecosystem Sciences, Brisbane, QLD 4001, Australia
Center for Computational and Theoretical Biology, University of Würzburg, 97074 Würzburg, Germany
Department of Ecology and Ecosystem Management, Technical University of Munich, 85354 Freising, Germany
Author to whom correspondence should be addressed.
Insects 2020, 11(2), 125; https://doi.org/10.3390/insects11020125
Received: 1 December 2019 / Revised: 25 January 2020 / Accepted: 3 February 2020 / Published: 15 February 2020
(This article belongs to the Special Issue Mechanisms of Nutritional Resource Exploitation by Insects)
Bees need food of appropriate nutritional quality to maintain their metabolic functions. They largely obtain all required nutrients from floral resources, i.e., pollen and nectar. However, the diversity, composition and nutritional quality of floral resources varies with the surrounding environment and can be strongly altered in human-impacted habitats. We investigated whether differences in plant species richness as found in the surrounding environment correlated with variation in the floral diversity and nutritional quality of larval provisions (i.e., mixtures of pollen, nectar and salivary secretions) composed by the mass-provisioning stingless bee Tetragonula carbonaria (Apidae: Meliponini). We found that the floral diversity of larval provisions increased with increasing plant species richness. The sucrose and fat (total fatty acid) content and the proportion and concentration of the omega-6 fatty acid linoleic acid decreased, whereas the proportion of the omega-3 fatty acid linolenic acid increased with increasing plant species richness. Protein (total amino acid) content and amino acid composition did not change. The protein to fat (P:F) ratio, known to affect bee foraging, increased on average by more than 40% from plantations to forests and gardens, while the omega-6:3 ratio, known to negatively affect cognitive performance, decreased with increasing plant species richness. Our results suggest that plant species richness may support T. carbonaria colonies by providing not only a continuous resource supply (as shown in a previous study), but also floral resources of high nutritional quality.