Forager age and foraging state, but not cumulative foraging activity, affect biogenic amine receptor gene expression in the honeybee mushroom bodies. (4th January 2021)

• Record Type: Journal Article
• Authors: Peng, Tianfei; Derstroff, Dennis; Maus, Lea; Bauer, Timo; Grüter, Christoph
• Is Part Of: Genes, brain, and behavior. Volume 20:Number 4(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-04
• Subjects: age -- biogenic amine receptor -- daytime -- experience -- foragers -- motivation; Behavior genetics -- Periodicals; Neurogenetics -- Periodicals; 616.8
• DOI: 10.1111/gbb.12722
• Languages: English
• ISSNs: 1601-1848

Abstract

Abstract: Foraging behavior is crucial for the development of a honeybee colony. Biogenic amines are key mediators of learning and the transition from in‐hive tasks to foraging. Foragers vary considerably in their behavior, but whether and how this behavioral diversity depends on biogenic amines is not yet well understood. For example, forager age, cumulative foraging activity or foraging state may all be linked to biogenic amine signaling. Furthermore, expression levels may fluctuate depending on daytime. We tested if these intrinsic and extrinsic factors are linked to biogenic amine signaling by quantifying the expression of octopamine, dopamine and tyramine receptor genes in the mushroom bodies, important tissues for learning and memory. We found that older foragers had a significantly higher expression of Amdop1, Amdop2, AmoctαR1, and AmoctβR1 compared to younger foragers, whereas Amtar1 showed the opposite pattern. Surprisingly, our measures of cumulative foraging activity were not related to the expression of the same receptor genes in the mushroom bodies. Furthermore, we trained foragers to collect sucrose solution at a specific time of day and tested if the foraging state of time‐trained foragers affected receptor gene expression. Bees engaged in foraging had a higher expression of Amdop1 and AmoctβR3/4 than inactive foragers. Finally, the expression of Amdop1, Amdop3, AmoctαR1, and Amtar1 also varied with daytime. Our results show that receptor gene expression in forager mushroom bodies is complex and depends on both intrinsic and extrinsic factors. Abstract : Foraging is important for the survival of an insect colony and is often performed by older workers. Biogenic amines play an important role in regulating physiological responses and, ultimately, animal behaviour. In honeybees the potential links between forager age, activity, foraging state and time of day time are not well explored. Here, we quantified the expression of octopamine, dopamine and tyramine receptor genes in the mushroom bodies with quantitative polymerase chain reaction and found that receptor gene expression depends on age, but surprisingly not on cumulative foraging activity. Moreover, foraging state and time of day affect receptor gene expression. Overall, our results reveal complex links between forager state and biogenic amine signaling in the mushroom bodies. They also highlight that more research is needed to understand how biogenic amine receptor expression in foragers is linked to extrinsic and intrinsic factors.