Elucidating the role of neurotransmitters in the behavioural plasticity of Camponotus compressus (Hymenoptera: Formicidae)

Ants express a remarkable behavioural plasticity ranging far beyond rigid stimulus-response relationships. They are omnivorous and each caste exhibit a variety of behaviour including nesting (foraging, food storage, protection from predators, feeding, nest structure and brood care). The behaviour investment of workers is shaped by presence or absence of queen within the colony; which may affect the behavioural flexibility and developmental neuroplasticity in workers. However, there is a lacuna in the studies conducted in the nesting behaviour and the associated neurophysiology of such ants. So, the present study was aimed to determine the role of neurotransmitters (Dopamine and Serotonin) underlining neuroplasticity in the nesting behaviour−foraging, feeding, searching, immobility, communication, defence, and nest structure of Camponotus compressus ant, under laboratory conditions. Our results demonstrated an increase in the respective behavioural activities, as well as in the length and depth of the nest, in the presence of the queen, with a subsequent decrease on the 14th day following her removal. Additionally, neurotransmitter levels (DA and 5-HT) were higher in workers (media and minor) ants on the 7th day, followed by a significant ( p < 0.05 ) decline after 14th day suggesting a reduced nesting activity, which is further correlated with the decrease in nest morphometry, in comparison to control. The current study unveils the neurophysiological mechanism involved in achieving neuroplasticity in the C. compressus . Further studies on specific gene expressions and histochemistry of brain will provide a broader view on the altered nesting behaviour in worker ants and the developed plastic queen.