@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}
}
@article{BehrendsScheiner2012,
  author    = {Behrends, Andreas and Scheiner, Ricarda},
  title     = {Octopamine improves learning in newly emerged bees but not in old foragers},
  series = {JOURNAL OF EXPERIMENTAL BIOLOGY},
  volume    = {215},
  journal   = {JOURNAL OF EXPERIMENTAL BIOLOGY},
  number    = {7},
  publisher = {COMPANY OF BIOLOGISTS LTD},
  address   = {CAMBRIDGE},
  issn      = {0022-0949},
  doi       = {10.1242/jeb.063297},
  pages     = {1076 -- 1083},
  year      = {2012},
  abstract  = {Honey bees (Apis mellifera) are well known for their excellent learning abilities. Although most age groups learn quickly to associate an odor with a sucrose reward, newly emerged bees and old foragers often perform poorly. For a long time, the reason for the poor learning performance of these age groups was unclear. We show that reduced sensitivity for sucrose is the cause for poor associative learning in newly emerged bees but not in old foragers. By increasing the sensitivity for sucrose through octopamine, we selectively improved the learning performance of insensitive newly emerged bees. Interestingly, the learning performance of foragers experiencing the same treatment remained low, despite the observed increase in sensitivity for the reward. We thus demonstrate that increasing sensitivity for the reward can improve the associative learning performance of bees when they are young but not when they had foraged for a long time. Importantly, octopamine can have very different effects on bees, depending on their initial sensory sensitivity. These differential effects of octopamine have important consequences for interpreting the action of biogenic amines on insect behavior.},
  language  = {en}
}