@article{SchilcherThammStrubeBlossetal.2021, author = {Schilcher, Felix and Thamm, Markus and Strube-Bloss, Martin and Scheiner, Ricarda}, title = {Opposing actions of octopamine and tyramine on honeybee vision}, series = {Biomolecules}, volume = {11}, journal = {Biomolecules}, number = {9}, issn = {2218-273X}, doi = {10.3390/biom11091374}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246214}, year = {2021}, abstract = {The biogenic amines octopamine and tyramine are important neurotransmitters in insects and other protostomes. They play a pivotal role in the sensory responses, learning and memory and social organisation of honeybees. Generally, octopamine and tyramine are believed to fulfil similar roles as their deuterostome counterparts epinephrine and norepinephrine. In some cases opposing functions of both amines have been observed. In this study, we examined the functions of tyramine and octopamine in honeybee responses to light. As a first step, electroretinography was used to analyse the effect of both amines on sensory sensitivity at the photoreceptor level. Here, the maximum receptor response was increased by octopamine and decreased by tyramine. As a second step, phototaxis experiments were performed to quantify the behavioural responses to light following treatment with either amine. Octopamine increased the walking speed towards different light sources while tyramine decreased it. This was independent of locomotor activity. Our results indicate that tyramine and octopamine act as functional opposites in processing responses to light.}, language = {en} } @article{HensgenEnglandHombergetal.2021, author = {Hensgen, Ronja and England, Laura and Homberg, Uwe and Pfeiffer, Keram}, title = {Neuroarchitecture of the central complex in the brain of the honeybee: Neuronal cell types}, series = {Journal of Comparative Neurology}, volume = {529}, journal = {Journal of Comparative Neurology}, doi = {10.1002/cne.24941}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-215566}, pages = {159-186}, year = {2021}, abstract = {The central complex (CX) in the insect brain is a higher order integration center that controls a number of behaviors, most prominently goal directed locomotion. The CX comprises the protocerebral bridge (PB), the upper division of the central body (CBU), the lower division of the central body (CBL), and the paired noduli (NO). Although spatial orientation has been extensively studied in honeybees at the behavioral level, most electrophysiological and anatomical analyses have been carried out in other insect species, leaving the morphology and physiology of neurons that constitute the CX in the honeybee mostly enigmatic. The goal of this study was to morphologically identify neuronal cell types of the CX in the honeybee Apis mellifera. By performing iontophoretic dye injections into the CX, we traced 16 subtypes of neuron that connect a subdivision of the CX with other regions in the bee's central brain, and eight subtypes that mainly interconnect different subdivisions of the CX. They establish extensive connections between the CX and the lateral complex, the superior protocerebrum and the posterior protocerebrum. Characterized neuron classes and subtypes are morphologically similar to those described in other insects, suggesting considerable conservation in the neural network relevant for orientation.}, language = {en} } @article{VillagomezNuernbergerRequieretal.2021, author = {Villagomez, Gemma N. and N{\"u}rnberger, Fabian and Requier, Fabrice and Schiele, Susanne and Steffan-Dewenter, Ingo}, title = {Effects of temperature and photoperiod on the seasonal timing of Western honey bee colonies and an early spring flowering plant}, series = {Ecology and Evolution}, volume = {11}, journal = {Ecology and Evolution}, number = {12}, doi = {10.1002/ece3.7616}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258770}, pages = {7834-7849}, year = {2021}, abstract = {Temperature and photoperiod are important Zeitgebers for plants and pollinators to synchronize growth and reproduction with suitable environmental conditions and their mutualistic interaction partners. Global warming can disturb this temporal synchronization since interacting species may respond differently to new combinations of photoperiod and temperature under future climates, but experimental studies on the potential phenological responses of plants and pollinators are lacking. We simulated current and future combinations of temperature and photoperiod to assess effects on the overwintering and spring phenology of an early flowering plant species (Crocus sieberi) and the Western honey bee (Apis mellifera). We could show that increased mean temperatures in winter and early spring advanced the flowering phenology of C. sieberi and intensified brood rearing activity of A. mellifera but did not advance their brood rearing activity. Flowering phenology of C. sieberi also relied on photoperiod, while brood rearing activity of A. mellifera did not. The results confirm that increases in temperature can induce changes in phenological responses and suggest that photoperiod can also play a critical role in these responses, with currently unknown consequences for real-world ecosystems in a warming climate.}, language = {en} } @article{ScheinerLimMeixneretal.2021, author = {Scheiner, Ricarda and Lim, Kayun and Meixner, Marina D. and Gabel, Martin S.}, title = {Comparing the appetitive learning performance of six European honeybee subspecies in a common apiary}, series = {Insects}, volume = {12}, journal = {Insects}, number = {9}, issn = {2075-4450}, doi = {10.3390/insects12090768}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245180}, year = {2021}, abstract = {The Western honeybee (Apis mellifera L.) is one of the most widespread insects with numerous subspecies in its native range. How far adaptation to local habitats has affected the cognitive skills of the different subspecies is an intriguing question that we investigate in this study. Naturally mated queens of the following five subspecies from different parts of Europe were transferred to Southern Germany: A. m. iberiensis from Portugal, A. m. mellifera from Belgium, A. m. macedonica from Greece, A. m. ligustica from Italy, and A. m. ruttneri from Malta. We also included the local subspecies A. m. carnica in our study. New colonies were built up in a common apiary where the respective queens were introduced. Worker offspring from the different subspecies were compared in classical olfactory learning performance using the proboscis extension response. Prior to conditioning, we measured individual sucrose responsiveness to investigate whether possible differences in learning performances were due to differential responsiveness to the sugar water reward. Most subspecies did not differ in their appetitive learning performance. However, foragers of the Iberian honeybee, A. m. iberiensis, performed significantly more poorly, despite having a similar sucrose responsiveness. We discuss possible causes for the poor performance of the Iberian honeybees, which may have been shaped by adaptation to the local habitat.}, language = {en} }