@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}
}
@article{Scheiner2012,
  author    = {Scheiner, Ricarda},
  title     = {Birth weight and sucrose responsiveness predict cognitive skills of honeybee foragers},
  series = {Animal behaviour},
  volume    = {84},
  journal   = {Animal behaviour},
  number    = {2},
  publisher = {Elsevier},
  address   = {London},
  issn      = {0003-3472},
  doi       = {10.1016/j.anbehav.2012.05.011},
  pages     = {305 -- 308},
  year      = {2012},
  abstract  = {Honeybees, Apis mellifera, can differ considerably in their birth weights but the consequences of these weight differences for behaviour are unknown. I investigated how these birth weight differences affected their cognitive skills when the bees reached foraging age. Individual sucrose responsiveness measured by the proboscis extension response is a strong determinant of appetitive olfactory learning performance in honeybees. Most of the observed learning differences between individuals or between genetic bee strains correlate with differences in their sucrose responsiveness. My second aim was therefore to investigate whether the sucrose responsiveness of newly emerged bees could predict the learning behaviour of the bees 3 weeks later. Both birth weight and sucrose responsiveness measured at emergence could predict olfactory learning scores as demonstrated by significant positive correlations. Heavy bees and bees with high sucrose responsiveness later learned better than lighter individuals or bees with lower responsiveness to sucrose at emergence. These results demonstrate for the first time a fundamental relationship between sensory responsiveness and morphology at emergence and later cognitive skills in insects. Because sensory responsiveness is closely linked to division of labour in honeybees, differences in weight and sucrose responsiveness at emergence might be involved in regulating division of labour.},
  language  = {en}
}