@article{KaluzaWallaceKelleretal.2017, author = {Kaluza, Benjamin F. and Wallace, Helen and Keller, Alexander and Heard, Tim A. and Jeffers, Bradley and Drescher, Nora and Bl{\"u}thgen, Nico and Leonhardt, Sara D.}, title = {Generalist social bees maximize diversity intake in plant species-rich and resource-abundant environments}, series = {Ecosphere}, volume = {8}, journal = {Ecosphere}, number = {3}, doi = {10.1002/ecs2.1758}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171155}, pages = {e01758}, year = {2017}, abstract = {Numerous studies revealed a positive relationship between biodiversity and ecosystem functioning, suggesting that biodiverse environments may not only enhance ecosystem processes, but also benefit individual ecosystem members by, for example, providing a higher diversity of resources. Whether and how the number of available resources affects resource collection and subsequently consumers (e.g., through impacting functions associated with resources) have, however, been little investigated, although a better understanding of this relationship may help explain why the abundance and richness of many animal species typically decline with decreasing plant (resource) diversity. Using a social bee species as model (Tetragonula carbonaria), we investigated how plant species richness—recorded for study sites located in different habitats—and associated resource abundance affected the diversity and functionality (here defined as nutritional content and antimicrobial activity) of resources (i.e., pollen, nectar, and resin) collected by a generalist herbivorous consumer. The diversity of both pollen and resin collected strongly increased with increasing plant/tree species richness, while resource abundance was only positively correlated with resin diversity. These findings suggest that bees maximize resource diversity intake in (resource) diverse habitats. Collecting more diverse resources did, however, not increase their functionality, which appeared to be primarily driven by the surrounding (plant) source community in our study. In generalist herbivores, maximizing resource diversity intake may therefore primarily secure collection of sufficient amounts of resources across the entire foraging season, but it also ensures that the allocated resources meet all functional needs. Decreasing available resource diversity may thus impact consumers primarily by reduced resource abundance, but also by reduced resource functionality, particularly when resources of high functionality (e.g., from specific plant species) become scarce.}, language = {en} } @article{KaluzaWallaceHeardetal.2016, author = {Kaluza, Benjamin F. and Wallace, Helen and Heard, Tim A. and Klein, Aelxandra-Maria and Leonhardt, Sara D.}, title = {Urban gardens promote bee foraging over natural habitats and plantations}, series = {Ecology and Evolution}, volume = {6}, journal = {Ecology and Evolution}, number = {5}, doi = {10.1002/ece3.1941}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162713}, pages = {1304-1316}, year = {2016}, abstract = {Increasing human land use for agriculture and housing leads to the loss of natural habitat and to widespread declines in wild bees. Bee foraging dynamics and fitness depend on the availability of resources in the surrounding landscape, but how precisely landscape related resource differences affect bee foraging patterns remains unclear. To investigate how landscape and its interaction with season and weather drive foraging and resource intake in social bees, we experimentally compared foraging activity, the allocation of foragers to different resources (pollen, nectar, and resin) and overall resource intake in the Australian stingless bee Tetragonula carbonaria (Apidae, Meliponini). Bee colonies were monitored in different seasons over two years. We compared foraging patterns and resource intake between the bees' natural habitat (forests) and two landscapes differently altered by humans (suburban gardens and agricultural macadamia plantations). We found foraging activity as well as pollen and nectar forager numbers to be highest in suburban gardens, intermediate in forests and low in plantations. Foraging patterns further differed between seasons, but seasonal variations strongly differed between landscapes. Sugar and pollen intake was low in plantations, but contrary with our predictions, it was even higher in gardens than in forests. In contrast, resin intake was similar across landscapes. Consequently, differences in resource availability between natural and altered landscapes strongly affect foraging patterns and thus resource intake in social bees. While agricultural monocultures largely reduce foraging success, suburban gardens can increase resource intake well above rates found in natural habitats of bees, indicating that human activities can both decrease and increase the availability of resources in a landscape and thus reduce or enhance bee fitness.}, language = {en} } @article{KaluzaWallaceHeardetal.2018, author = {Kaluza, Benjamin F. and Wallace, Helen M. and Heard, Tim A. and Minden, Vanessa and Klein, Alexandra and Leonhardt, Sara D.}, title = {Social bees are fitter in more biodiverse environments}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, number = {12353}, doi = {10.1038/s41598-018-30126-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177231}, year = {2018}, abstract = {Bee population declines are often linked to human impacts, especially habitat and biodiversity loss, but empirical evidence is lacking. To clarify the link between biodiversity loss and bee decline, we examined how floral diversity affects (reproductive) fitness and population growth of a social stingless bee. For the first time, we related available resource diversity and abundance to resource (quality and quantity) intake and colony reproduction, over more than two years. Our results reveal plant diversity as key driver of bee fitness. Social bee colonies were fitter and their populations grew faster in more florally diverse environments due to a continuous supply of food resources. Colonies responded to high plant diversity with increased resource intake and colony food stores. Our findings thus point to biodiversity loss as main reason for the observed bee decline.}, language = {en} } @article{TrinklKaluzaWallaceetal.2020, author = {Trinkl, Moritz and Kaluza, Benjamin F. and Wallace, Helen and Heard, Tim A. and Keller, Alexander and Leonhardt, Sara D.}, title = {Floral Species Richness Correlates with Changes in the Nutritional Quality of Larval Diets in a Stingless Bee}, series = {Insects}, volume = {11}, journal = {Insects}, number = {2}, issn = {2075-4450}, doi = {10.3390/insects11020125}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200605}, pages = {125}, year = {2020}, abstract = {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.}, language = {en} }