@article{ScheinerEntlerBarronetal.2017,
  author    = {Scheiner, Ricarda and Entler, Brian V. and Barron, Andrew B. and Scholl, Christina and Thamm, Markus},
  title     = {The Effects of Fat Body Tyramine Level on Gustatory Responsiveness of Honeybees (Apis mellifera) Differ between Behavioral Castes},
  series = {Frontiers in Systems Neuroscience},
  volume    = {11},
  journal   = {Frontiers in Systems Neuroscience},
  number    = {55},
  doi       = {10.3389/fnsys.2017.00055},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157874},
  year      = {2017},
  abstract  = {Division of labor is a hallmark of social insects. In the honeybee (Apis mellifera) each sterile female worker performs a series of social tasks. The most drastic changes in behavior occur when a nurse bee, who takes care of the brood and the queen in the hive, transitions to foraging behavior. Foragers provision the colony with pollen, nectar or water. Nurse bees and foragers differ in numerous behaviors, including responsiveness to gustatory stimuli. Differences in gustatory responsiveness, in turn, might be involved in regulating division of labor through differential sensory response thresholds. Biogenic amines are important modulators of behavior. Tyramine and octopamine have been shown to increase gustatory responsiveness in honeybees when injected into the thorax, thereby possibly triggering social organization. So far, most of the experiments investigating the role of amines on gustatory responsiveness have focused on the brain. The potential role of the fat body in regulating sensory responsiveness and division of labor has large been neglected. We here investigated the role of the fat body in modulating gustatory responsiveness through tyramine signaling in different social roles of honeybees. We quantified levels of tyramine, tyramine receptor gene expression and the effect of elevating fat body tyramine titers on gustatory responsiveness in both nurse bees and foragers. Our data suggest that elevating the tyramine titer in the fat body pharmacologically increases gustatory responsiveness in foragers, but not in nurse bees. This differential effect of tyramine on gustatory responsiveness correlates with a higher natural gustatory responsiveness of foragers, with a higher tyramine receptor (Amtar1) mRNA expression in fat bodies of foragers and with lower baseline tyramine titers in fat bodies of foragers compared to those of nurse bees. We suggest that differential tyramine signaling in the fat body has an important role in the plasticity of division of labor through changing gustatory responsiveness.},
  language  = {en}
}
@article{HabensteinThammRoessler2021,
  author    = {Habenstein, Jens and Thamm, Markus and R{\"o}ssler, Wolfgang},
  title     = {Neuropeptides as potential modulators of behavioral transitions in the ant Cataglyphis nodus},
  series = {Journal of Comparative Neurology},
  volume    = {529},
  journal   = {Journal of Comparative Neurology},
  number    = {12},
  doi       = {10.1002/cne.25166},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244751},
  pages     = {3155 -- 3170},
  year      = {2021},
  abstract  = {Age-related behavioral plasticity is a major prerequisite for the ecological success of insect societies. Although ecological aspects of behavioral flexibility have been targeted in many studies, the underlying intrinsic mechanisms controlling the diverse changes in behavior along the individual life history of social insects are not completely understood. Recently, the neuropeptides allatostatin-A, corazonin, and tachykinin have been associated with the regulation of behavioral transitions in social insects. Here, we investigated changes in brain localization and expression of these neuropeptides following major behavioral transitions in Cataglyphis nodus ants. Our immunohistochemical analyses in the brain revealed that the overall branching pattern of neurons immunoreactive (ir) for the three neuropeptides is largely independent of the behavioral stages. Numerous allatostatin-A- and tachykinin-ir neurons innervate primary sensory neuropils and high-order integration centers of the brain. In contrast, the number of corazonergic neurons is restricted to only four neurons per brain hemisphere with cell bodies located in the pars lateralis and axons extending to the medial protocerebrum and the retrocerebral complex. Most interestingly, the cell-body volumes of these neurons are significantly increased in foragers compared to freshly eclosed ants and interior workers. Quantification of mRNA expression levels revealed a stage-related change in the expression of allatostatin-A and corazonin mRNA in the brain. Given the presence of the neuropeptides in major control centers of the brain and the neurohemal organs, these mRNA-changes strongly suggest an important modulatory role of both neuropeptides in the behavioral maturation of Cataglyphis ants.},
  language  = {en}
}