@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{SchilcherHilsmannRauscheretal.2021,
  author    = {Schilcher, Felix and Hilsmann, Lioba and Rauscher, Lisa and Değirmenci, Laura and Krischke, Markus and Krischke, Beate and Ankenbrand, Markus and Rutschmann, Benjamin and Mueller, Martin J. and Steffan-Dewenter, Ingolf and Scheiner, Ricarda},
  title     = {In vitro rearing changes social task performance and physiology in honeybees},
  series = {Insects},
  volume    = {13},
  journal   = {Insects},
  number    = {1},
  issn      = {2075-4450},
  doi       = {10.3390/insects13010004},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-252305},
  year      = {2021},
  abstract  = {In vitro rearing of honeybee larvae is an established method that enables exact control and monitoring of developmental factors and allows controlled application of pesticides or pathogens. However, only a few studies have investigated how the rearing method itself affects the behavior of the resulting adult honeybees. We raised honeybees in vitro according to a standardized protocol: marking the emerging honeybees individually and inserting them into established colonies. Subsequently, we investigated the behavioral performance of nurse bees and foragers and quantified the physiological factors underlying the social organization. Adult honeybees raised in vitro differed from naturally reared honeybees in their probability of performing social tasks. Further, in vitro-reared bees foraged for a shorter duration in their life and performed fewer foraging trips. Nursing behavior appeared to be unaffected by rearing condition. Weight was also unaffected by rearing condition. Interestingly, juvenile hormone titers, which normally increase strongly around the time when a honeybee becomes a forager, were significantly lower in three- and four-week-old in vitro bees. The effects of the rearing environment on individual sucrose responsiveness and lipid levels were rather minor. These data suggest that larval rearing conditions can affect the task performance and physiology of adult bees despite equal weight, pointing to an important role of the colony environment for these factors. Our observations of behavior and metabolic pathways offer important novel insight into how the rearing environment affects adult honeybees.},
  language  = {en}
}
@article{KablauBergRutschmannetal.2020,
  author    = {Kablau, Arne and Berg, Stefan and Rutschmann, Benjamin and Scheiner, Ricarda},
  title     = {Short-term hyperthermia at larval age reduces sucrose responsiveness of adult honeybees and can increase life span},
  series = {Apidologie},
  volume    = {51},
  journal   = {Apidologie},
  issn      = {0044-8435},
  doi       = {10.1007/s13592-020-00743-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-232462},
  pages     = {570-582},
  year      = {2020},
  abstract  = {Honeybees are very sensitive to their breeding temperature. Even slightly lower temperatures during larval development can significantly affect adult behavior. Several devices which are employed for killing the honeybee ectoparasite Varroa destructor rely on short-term hyperthermia in the honeybee hive. The device used here applies 43.7 °C for 2 h, which is highly effective in killing the mites. We study how short-term hyperthermia affects worker brood and behavior of emerging adult bees. Sucrose responsiveness was strongly reduced after treatment of larvae early or late of larval development. Hyperthermia significantly enhanced life span, particularly in bees receiving treated early in larval development. To ask whether increased life span correlated with foraging performance, we used radio frequency identification (RFID). Onset and offset of foraging behavior as well as foraging trip duration and lifetime foraging effort were unaffected by hyperthermia treatment as prepupa.},
  language  = {en}
}
@article{RequierPailletLarocheetal.2019,
  author    = {Requier, Fabrice and Paillet, Yoan and Laroche, Fabienne and Rutschmann, Benjamin and Zhang, Jie and Lombardi, Fabio and Svoboda, Miroslav and Steffan-Dewenter, Ingolf},
  title     = {Contribution of European forests to safeguard wild honeybee populations},
  series = {Conservation Letters},
  volume    = {13},
  journal   = {Conservation Letters},
  number    = {2},
  doi       = {10.1111/conl.12693},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-204407},
  pages     = {e12693},
  year      = {2019},
  abstract  = {Abstract Recent studies reveal the use of tree cavities by wild honeybee colonies in European forests. This highlights the conservation potential of forests for a highly threatened component of the native entomofauna in Europe, but currently no estimate of potential wild honeybee population sizes exists. Here, we analyzed the tree cavity densities of 106 forest areas across Europe and inferred an expected population size of wild honeybees. Both forest and management types affected the density of tree cavities. Accordingly, we estimated that more than 80,000 wild honeybee colonies could be sustained in European forests. As expected, potential conservation hotspots were identified in unmanaged forests, and, surprisingly, also in other large forest areas across Europe. Our results contribute to the EU policy strategy to halt pollinator declines and reveal the potential of forest areas for the conservation of so far neglected wild honeybee populations in Europe.},
  language  = {en}
}
@article{KohlRutschmann2018,
  author    = {Kohl, Patrick Laurenz and Rutschmann, Benjamin},
  title     = {The neglected bee trees: European beech forests as a home for feral honey bee colonies},
  series = {PeerJ},
  volume    = {6},
  journal   = {PeerJ},
  number    = {e4602},
  doi       = {10.7717/peerj.4602},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176512},
  year      = {2018},
  abstract  = {It is a common belief that feral honey bee colonies (Apis mellifera L.) were eradicated in Europe through the loss of habitats, domestication by man and spread of pathogens and parasites. Interestingly, no scientific data are available, neither about the past nor the present status of naturally nesting honeybee colonies. We expected near-natural beech (Fagus sylvatica L.) forests to provide enough suitable nest sites to be a home for feral honey bee colonies in Europe. Here, we made a first assessment of their occurrence and density in two German woodland areas based on two methods, the tracing of nest sites based on forager flight routes (beelining technique), and the direct inspection of potential cavity trees. Further, we established experimental swarms at forest edges and decoded dances for nest sites performed by scout bees in order to study how far swarms from beekeeper-managed hives would potentially move into a forest. We found that feral honey bee colonies regularly inhabit tree cavities in near-natural beech forests at densities of at least 0.11-0.14 colonies/km\(^{2}\). Colonies were not confined to the forest edges; they were also living deep inside the forests. We estimated a median distance of 2,600 m from the bee trees to the next apiaries, while scout bees in experimental swarms communicated nest sites in close distances (median: 470 m). We extrapolate that there are several thousand feral honey bee colonies in German woodlands. These have to be taken in account when assessing the role of forest areas in providing pollination services to the surrounding land, and their occurrence has implications for the species' perception among researchers, beekeepers and conservationists. This study provides a starting point for investigating the life-histories and the ecological interactions of honey bees in temperate European forest environments.},
  language  = {en}
}