Learning, gustatory responsiveness and tyramine differences across nurse and forager honeybees.
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.
University of Würzburg, Behavioral Physiology & Sociobiology, Biocenter, Am Hubland, Würzburg 97074, Germany ricarda.scheiner@uni-wuerzburg.de.|University of Potsdam, Institute for Biochemistry and Biology, Potsdam 14476, Germany.
Ricarda
0000-0002-7515-4253
R
Scheiner
University of Potsdam, Institute for Biochemistry and Biology, Potsdam 14476, Germany.
Tina
T
Reim
Macquarie University, Department of Biological Sciences, Sydney, NSW 2109, Australia.|Volda University College, Department of Science and Mathematics, Volda 6100, Norway.
Eirik
E
Søvik
Macquarie University, Department of Biological Sciences, Sydney, NSW 2109, Australia.
Brian V
BV
Entler
Macquarie University, Department of Biological Sciences, Sydney, NSW 2109, Australia.
Andrew B
AB
Barron
University of Würzburg, Behavioral Physiology & Sociobiology, Biocenter, Am Hubland, Würzburg 97074, Germany.
Markus
M
Thamm
D000818:Animals; D001070:Appetitive Behavior; D001516:Bees / Q000502:physiology*; D001522:Behavior, Animal; D003214:Conditioning, Classical; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009655:Octopamine / Q000032:analysis / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D017982:Receptors, Biogenic Amine / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D012903:Smell; D012919:Social Behavior; D013649:Taste; D014439:Tyramine / Q000032:analysis / Q000378:metabolism*
D019476:Insect Proteins; D012333:RNA, Messenger; D017982:Receptors, Biogenic Amine; C066175:tyramine receptor; D009655:Octopamine; D014439:Tyramine
Apis mellifera; Biogenic amines; Nurse bee; PER; Proboscis extension response