TY - JOUR A1 - Thamm, Markus A1 - Scholl, Christina A1 - Reim, Tina A1 - Gruebel, Kornelia A1 - Moeller, Karin A1 - Rossler, Wolfgang A1 - Scheiner, Ricarda T1 - Neuronal distribution of tyramine and the tyramine receptor AmTAR1 in the honeybee brain JF - The journal of comparative neurology N2 - Tyramine is an important neurotransmitter, neuromodulator, and neurohormone in insects. In honeybees, it is assumed to have functions in modulating sensory responsiveness and controlling motor behavior. Tyramine can bind to two characterized receptors in honeybees, both of which are coupled to intracellular cAMP pathways. How tyramine acts on neuronal, cellular and circuit levels is unclear. We investigated the spatial brain expression of the tyramine receptor AmTAR1 using a specific antibody. This antibody detects a membrane protein of the expected molecular weight in western blot analysis. In honeybee brains, it labels different structures which process sensory information. Labeling along the antennal nerve, in projections of the dorsal lobe and in the gnathal ganglion suggest that tyramine receptors are involved in modulating gustatory and tactile perception. Furthermore, the ellipsoid body of the central complex and giant synapses in the lateral complex show AmTAR1-like immunoreactivity (AmTAR1-IR), suggesting a role of this receptor in modulating sky-compass information and/or higher sensor-motor control. Additionally, intense signals derive from the mushroom bodies, higher-order integration centers for olfactory, visual, gustatory and tactile information. To investigate whether AmTAR1-expressing brain structures are in vicinity to tyramine releasing sites, a specific tyramine antibody was applied. Tyramine-like labeling was observed in AmTAR1-IR positive structures, although it was sometimes weak and we did not always find a direct match of ligand and receptor. Moreover, tyramine-like immunoreactivity was also found in brain regions without AmTAR1-IR (optic lobes, antennal lobes), indicating that other tyramine-specific receptors may be expressed there. KW - antibody KW - biogenic amines KW - G-protein coupled receptor KW - honeybee KW - tyramine Y1 - 2017 U6 - https://doi.org/10.1002/cne.24228 SN - 0021-9967 SN - 1096-9861 VL - 525 SP - 2615 EP - 2631 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Scheiner, Ricarda T1 - Birth weight and sucrose responsiveness predict cognitive skills of honeybee foragers JF - Animal behaviour N2 - 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. KW - Apis mellifera KW - birth weight KW - division of labour KW - foraging KW - honeybee KW - learning KW - maternal provisioning KW - sucrose responsiveness Y1 - 2012 U6 - https://doi.org/10.1016/j.anbehav.2012.05.011 SN - 0003-3472 VL - 84 IS - 2 SP - 305 EP - 308 PB - Elsevier CY - London ER - TY - GEN A1 - Scheiner, Ricarda A1 - Baumann, Arnd A1 - Blenau, Wolfgang T1 - Aminergic control and modulation of honeybee behaviour N2 - Biogenic amines are important messenger substances in the central nervous system and in peripheral organs of vertebrates and of invertebrates. The honeybee, Apis mellifera, is excellently suited to uncover the functions of biogenic amines in behaviour, because it has an extensive behavioural repertoire, with a number of biogenic amine receptors characterised in this insect. In the honeybee, the biogenic amines dopamine, octopamine, serotonin and tyramine modulate neuronal functions in various ways. Dopamine and serotonin are present in high concentrations in the bee brain, whereas octopamine and tyramine are less abundant. Octopamine is a key molecule for the control of honeybee behaviour. It generally has an arousing effect and leads to higher sensitivity for sensory inputs, better learning performance and increased foraging behaviour. Tyramine has been suggested to act antagonistically to octopamine, but only few experimental data are available for this amine. Dopamine and serotonin often have antagonistic or inhibitory effects as compared to octopamine. Biogenic amines bind to membrane receptors that primarily belong to the large gene-family of GTP-binding (G) protein coupled receptors. Receptor activation leads to transient changes in concentrations of intracellular second messengers such as cAMP, IP3 and/or Ca2+. Although several biogenic amine receptors from the honeybee have been cloned and characterised more recently, many genes still remain to be identified. The availability of the completely sequenced genome of Apis mellifera will contribute substantially to closing this gap. In this review, we will discuss the present knowledge on how biogenic amines and their receptor-mediated cellular responses modulate different behaviours of honeybees including learning processes and division of labour. KW - Serotonin KW - dopamine KW - octopamine KW - tyramine KW - honeybee Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-46106 ER -