Abstract
Biogenic amines modulate a range of social behaviours, including sociability and mechanisms of group cohesion, in both vertebrates and invertebrates. Here, we tested if the biogenic amines modulate honey bee (Apis mellifera) sociability and nestmate affiliation. We examined the consequences of treatments with biogenic amines, agonists and antagonists on a bee’s approach to, and subsequent social interactions with, conspecifics in both naturally hive-reared bees and isolated bees. We used two different treatment methods. Bees were first treated topically with compounds dissolved in the solvent dimethylformamide (dMF) applied to the dorsal thorax, but dMF had a significant effect on the locomotion and behaviour of the bees during the behavioural test that interfered with their social responses. Our second method used microinjection to deliver biogenic amines to the head capsule via the ocellar tract. Microinjection of dopamine and a dopamine antagonist had strong effects on bee sociability, likelihood of interaction with bees, and nestmate affiliation. Octopamine treatment reduced social interaction with other bees, and serotonin increased the likelihood of social interactions. HPLC measurements showed that isolation reduced brain levels of biogenic amines compared to hive-reared bees. Our findings suggest that dopamine is an important neurochemical component of social motivation in bees. This finding advances a comparative understanding of the processes of social evolution.
Highlights
The biogenic amines are involved in many types of behaviour, including various social behaviours [1,2]
Robinson et al, [27] found a bidirectional effect of OA by increased aggression to NON and increased cohesion with NM, other studies tend to find OA predominantly increases aggression to unfamiliar conspecifics [28,29,30]. In this assay we found OA treatment of hive-reared bees led to no social interactions with stimulus bees
We report strong evidence for a causal role of DA in bee sociability and group cohesion, and corroborate findings connecting OA to eusocial insect social interactions
Summary
The biogenic amines (including dopamine, serotonin, octopamine) are involved in many types of behaviour, including various social behaviours [1,2]. Mechanistic studies of sociability (tendency to aggregate [3]) and affiliation have been most extensively studied in prairie voles (Microtus ochrogaster), as they form life long partnerships and coparent [4]. Part of the prairie vole partnership formation process involves learning the olfactory signature of the partner and associating the olfactory cue with reward [5]. Inhibiting the dopaminergic mesolimbic reward system inhibits a partner preference developing [5]. In both male and female voles, activation of the D2 dopamine receptor in the nucleus accumbens is key to partner preference formation [6,7,8,9], as well as dopamine (DA) activity in the basal ganglia [10]. Increases in DA levels and dopaminergic neuron activity have been linked to bird
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
