
@article {96102,
	title = {Tyramine 1 Receptor Distribution in the Brain of Corbiculate Bees Points to a Conserved Function.},
	journal = {Brain Behav Evol},
	year = {2021},
	month = {2021 Jul 15},
	pages = {1-13},
	abstract = {<p>Sucrose represents an important carbohydrate source for most bee species. In the Western honeybee (Apis mellifera) it was shown that individual sucrose responsiveness correlates with the task performed in the colony, supporting the response threshold theory which states that individuals with the lowest threshold for a task-associated stimuli will perform the associated task. Tyramine was shown to modulate sucrose responsiveness, most likely via the tyramine 1 receptor. This receptor is located in brain areas important for the processing of gustatory stimuli. We asked whether the spatial expression pattern of the tyramine 1 receptor is a unique adaptation of honeybees or if its expression represents a conserved trait. Using a specific tyramine receptor 1 antibody, we compared the spatial expression of this receptor in the brain of different corbiculate bee species, including eusocial honeybees, bumblebees, stingless bees, and the solitary bee Osmia bicornis as an outgroup. We found a similar labeling pattern in the mushroom bodies, the central complex, the dorsal lobe, and the gnathal ganglia, indicating a conserved receptor expression. With respect to sucrose responsiveness this result is of special importance. We assume that the tyramine 1 receptor expression in these neuropiles provides the basis for modulation of sucrose responsiveness. Furthermore, the tyramine 1 receptor expression seems to be independent of size, as labeling is similar in bee species that differ greatly in their body size. However, the situation in the optic lobes appears to be different. Here, the lobula of stingless bees is clearly labeled by the tyramine receptor 1 antibody, whereas this labeling is absent in other species. This indicates that the regulation of this receptor is different in the optic lobes, while its function in this neuropile remains unclear.</p>
},
	issn = {1421-9743},
	doi = {10.1159/000517014},
	author = {Thamm, Markus and Wagler, Katharina and Brockmann, Axel and Scheiner, Ricarda}
}
@article {59709,
	title = {Inter-individual variation in honey bee dance intensity correlates with expression of the foraging gene.},
	journal = {Genes Brain Behav},
	volume = {19},
	year = {2020},
	month = {19/Jan},
	abstract = {<p>Individual behavioural differences in responding to the same stimuli is an integral part of division of labour in eusocial insect colonies. Among honey bee nectar foragers, individuals strongly differ in their sucrose responsiveness, which correlates with strong differences in behavioural decisions. In this study, we explored whether the mechanisms underlying the regulation of foraging are linked to inter-individual differences in the waggle dance activity of honey bee foragers. We first quantified the variation in dance activity amongst groups of foragers visiting an artificial feeder filled consecutively with different sucrose concentrations. We then determined for these foragers the sucrose responsiveness and the brain expression levels of three genes associated with food search and foraging; the foraging gene Amfor, octopamine receptor gene AmoctαR1 and insulin receptor AmInR-2. As expected, foragers showed large inter-individual differences in their dance activity, irrespective of the reward offered at the feeder. The sucrose responsiveness correlated positively with the intensity of the dance activity at the higher reward condition, with the more responsive foragers having a higher intensity of dancing. Out of the three genes tested, Amfor expression significantly correlated with dance activity, with more active dancers having lower expression levels. Our results show that dance and foraging behaviour in honey bees have similar mechanistic underpinnings and supports the hypothesis that the social communication behaviour of honey bees might have evolved by co-opting behavioural modules involved in food search and foraging in solitary insects.</p>
},
	issn = {1601-183X},
	doi = {10.1111/gbb.12592},
	author = {George, Ebi Antony and Br{\"o}ger, Ann-Kathrin and Thamm, Markus and Brockmann, Axel and Scheiner, Ricarda}
}
