@article{ScheinerTotevaReimetal.2014,
  author    = {Scheiner, Ricarda and Toteva, Anna and Reim, Tina and Sovik, Eirik and Barron, Andrew B.},
  title     = {Differences in the phototaxis of pollen and nectar foraging honey bees are related to their octopamine brain titers},
  series = {Frontiers in physiology},
  volume    = {5},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2014.00116},
  pages     = {8},
  year      = {2014},
  abstract  = {The biogenic amine octopamine is an important neuromodulator, neurohormone and neurotransmitter in insects. We here investigate the role of octopamine signaling in honey bee phototaxis. Our results show that groups of bees differ naturally in their phototaxis. Pollen forgers display a lower light responsiveness than nectar foragers. The lower phototaxis of pollen foragers coincides with higher octopamine titers in the optic lobes but is independent of octopamine receptor gene expression. Increasing octopamine brain titers reduces responsiveness to light, while tyramine application enhances phototaxis. These findings suggest an involvement of octopamine signaling in honey bee phototaxis and possibly division of labor, which is hypothesized to be based on individual differences in sensory responsiveness.},
  language  = {en}
}
@article{ScheinerReimSoviketal.2017,
  author    = {Scheiner, Ricarda and Reim, Tina and Sovik, Eirik and Entler, Brian V. and Barron, Andrew B. and Thamm, Markus},
  title     = {Learning, gustatory responsiveness and tyramine differences across nurse and forager honeybees},
  series = {The journal of experimental biology},
  volume    = {220},
  journal   = {The journal of experimental biology},
  publisher = {Company of Biologists Limited},
  address   = {Cambridge},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.152496},
  pages     = {1443 -- 1450},
  year      = {2017},
  abstract  = {Honeybees are well known for their complex division of labor. Each bee sequentially performs a series of social tasks during its life. The changes in social task performance are linked to gross differences in behavior and physiology. We tested whether honeybees performing different social tasks (nursing versus foraging) would differ in their gustatory responsiveness and associative learning behavior in addition to their daily tasks in the colony. Further, we investigated the role of the biogenic amine tyramine and its receptors in the behavior of nurse bees and foragers. Tyramine is an important insect neurotransmitter, which has long been neglected in behavioral studies as it was believed to only act as the metabolic precursor of the better-known amine octopamine. With the increasing number of characterized tyramine receptors in diverse insects, we need to understand the functions of tyramine on its own account. Our findings suggest an important role for tyramine and its two receptors in regulating honeybee gustatory responsiveness, social organization and learning behavior. Foragers, which were more responsive to gustatory stimuli than nurse bees and performed better in appetitive learning, also differed from nurse bees in their tyramine brain titers and in the mRNA expression of a tyramine receptor in the brain. Pharmacological activation of tyramine receptors increased gustatory responsiveness of nurse bees and foragers and improved appetitive learning in nurse bees. These data suggest that a large part of the behavioral differences between honeybees may be directly linked to tyramine signaling in the brain.},
  language  = {en}
}