@article{KohlRutschmannSteffanDewenter2022,
  author    = {Kohl, Patrick L. and Rutschmann, Benjamin and Steffan-Dewenter, Ingolf},
  title     = {Population demography of feral honeybee colonies in central European forests},
  series = {Royal Society Open Science},
  volume    = {9},
  journal   = {Royal Society Open Science},
  number    = {8},
  issn      = {2054-5703},
  doi       = {10.1098/rsos.220565},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301335},
  year      = {2022},
  abstract  = {European honeybee populations are considered to consist only of managed colonies, but recent censuses have revealed that wild/feral colonies still occur in various countries. To gauge the ecological and evolutionary relevance of wild-living honeybees, information is needed on their population demography. We monitored feral honeybee colonies in German forests for up to 4 years through regular inspections of woodpecker cavity trees and microsatellite genotyping. Each summer, about 10\% of the trees were occupied, corresponding to average densities of 0.23 feral colonies km\(^{-2}\) (an estimated 5\% of the regional honeybee populations). Populations decreased moderately until autumn but dropped massively during winter, so that their densities were only about 0.02 colonies km\(^{-2}\) in early spring. During the reproductive (swarming) season, in May and June, populations recovered, with new swarms preferring nest sites that had been occupied in the previous year. The annual survival rate and the estimated lifespan of feral colonies (n = 112) were 10.6\% and 0.6 years, respectively. We conclude that managed forests in Germany do not harbour self-sustaining feral honeybee populations, but they are recolonized every year by swarms escaping from apiaries.},
  language  = {en}
}
@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}
}