@article{GrundMuellerRuedenauerSpaetheetal.2020,
  author    = {Grund-Mueller, Nils and Ruedenauer, Fabian A. and Spaethe, Johannes and Leonhardt, Sara D.},
  title     = {Adding amino acids to a sucrose diet is not sufficient to support longevity of adult bumble bees},
  series = {Insects},
  volume    = {11},
  journal   = {Insects},
  number    = {4},
  issn      = {2075-4450},
  doi       = {10.3390/insects11040247},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203866},
  year      = {2020},
  abstract  = {Dietary macro-nutrients (i.e., carbohydrates, protein, and fat) are important for bee larval development and, thus, colony health and fitness. To which extent different diets (varying in macro-nutrient composition) affect adult bees and whether they can thrive on nectar as the sole amino acid source has, however, been little investigated. We investigated how diets varying in protein concentration and overall nutrient composition affected consumption, longevity, and breeding behavior of the buff-tailed bumble bee, Bombus terrestris (Hymenoptera: Apidae). Queenless micro-colonies were fed either natural nutrient sources (pollen), nearly pure protein (i.e., the milk protein casein), or sucrose solutions with low and with high essential amino acid content in concentrations as can be found in nectar. We observed micro-colonies for 110 days. We found that longevity was highest for pure pollen and lowest for pure sucrose solution and sucrose solution supplemented with amino acids in concentrations as found in the nectar of several plant species. Adding higher concentrations of amino acids to sucrose solution did only slightly increase longevity compared to sucrose alone. Consequently, sucrose solution with the applied concentrations and proportions of amino acids or other protein sources (e.g., casein) alone did not meet the nutritional needs of healthy adult bumble bees. In fact, longevity was highest and reproduction only successful in micro-colonies fed pollen. These results indicate that, in addition to carbohydrates and protein, adult bumble bees, like larvae, need further nutrients (e.g., lipids and micro-nutrients) for their well-being. An appropriate nutritional composition seemed to be best provided by floral pollen, suggesting that pollen is an essential dietary component not only for larvae but also for adult bees.},
  language  = {en}
}
@article{LehenbergerFohGoettleinetal.2021,
  author    = {Lehenberger, Maximilian and Foh, Nina and G{\"o}ttlein, Axel and Six, Diana and Biedermann, Peter H. W.},
  title     = {Nutrient-Poor Breeding Substrates of Ambrosia Beetles Are Enriched With Biologically Important Elements},
  series = {Frontiers in Microbiology},
  volume    = {12},
  journal   = {Frontiers in Microbiology},
  issn      = {1664-302X},
  doi       = {10.3389/fmicb.2021.664542},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-237602},
  year      = {2021},
  abstract  = {Fungus-farming within galleries in the xylem of trees has evolved independently in at least twelve lineages of weevils (Curculionidae: Scolytinae, Platypodinae) and one lineage of ship-timber beetles (Lymexylidae). Jointly these are termed ambrosia beetles because they actively cultivate nutritional "ambrosia fungi" as their main source of food. The beetles are obligately dependent on their ambrosia fungi as they provide them a broad range of essential nutrients ensuring their survival in an extremely nutrient-poor environment. While xylem is rich in carbon (C) and hydrogen (H), various elements essential for fungal and beetle growth, such as nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), and manganese (Mn) are extremely low in concentration. Currently it remains untested how both ambrosia beetles and their fungi meet their nutritional requirements in this habitat. Here, we aimed to determine for the first time if galleries of ambrosia beetles are generally enriched with elements that are rare in uncolonized xylem tissue and whether these nutrients are translocated to the galleries from the xylem by the fungal associates. To do so, we examined natural galleries of three ambrosia beetle species from three independently evolved farming lineages, Xyleborinus saxesenii (Scolytinae: Xyleborini), Trypodendron lineatum (Scolytinae: Xyloterini) and Elateroides dermestoides (Lymexylidae), that cultivate unrelated ambrosia fungi in the ascomycete orders Ophiostomatales, Microascales, and Saccharomycetales, respectively. Several elements, in particular Ca, N, P, K, Mg, Mn, and S, were present in high concentrations within the beetles' galleries but available in only very low concentrations in the surrounding xylem. The concentration of elements was generally highest with X. saxesenii, followed by T. lineatum and E. dermestoides, which positively correlates with the degree of sociality and productivity of brood per gallery. We propose that the ambrosia fungal mutualists are translocating essential elements through their hyphae from the xylem to fruiting structures they form on gallery walls. Moreover, the extremely strong enrichment observed suggests recycling of these elements from the feces of the insects, where bacteria and yeasts might play a role.},
  language  = {en}
}
@article{RuedenauerWoehrleSpaetheetal.2018,
  author    = {Ruedenauer, Fabian A. and W{\"o}hrle, Christine and Spaethe, Johannes and Leonhardt, Sara D.},
  title     = {Do honeybees (Apis mellifera) differentiate between different pollen types?},
  series = {PLoS ONE},
  volume    = {13},
  journal   = {PLoS ONE},
  number    = {11},
  doi       = {10.1371/journal.pone.0205821},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177537},
  pages     = {e0205821},
  year      = {2018},
  abstract  = {Bees receive nectar and pollen as reward for pollinating plants. Pollen of different plant species varies widely in nutritional composition. In order to select pollen of appropriate nutritional quality, bees would benefit if they could distinguish different pollen types. Whether they rely on visual, olfactory and/or chemotactile cues to distinguish between different pollen types, has however been little studied. In this study, we examined whether and how Apis mellifera workers differentiate between almond and apple pollen. We used differential proboscis extension response conditioning with olfactory and chemotactile stimulation, in light and darkness, and in summer and winter bees. We found that honeybees were only able to differentiate between different pollen types, when they could use both chemotactile and olfactory cues. Visual cues further improved learning performance. Summer bees learned faster than winter bees. Our results thus highlight the importance of multisensory information for pollen discrimination.},
  language  = {en}
}