Recent research has discovered that genotype in the leaf-cutting ant, Acromyrmex echinatior, influences certain aspects of caste specialisation. In general, studies are confounded by factors such as input of environment, behavioural flexibility and genotypic variation. Ants from a single colony fulfil model requirements. They have a single queen that produces offspring from multiple mates (each a patriline), a common environment and are behaviourally specialised. EU-funded NEUROANT project researchers used microsatellite sequencing to characterise the genotypes between the different castes. To determine the neuromechanisms behind genetic variation in division of labour, they tested for neurochemical and neuroanatomical differences. Results showed that gross brain morphology differed very little between the specialised workers (there are four castes) or between patrilines. However, there were differences in biogenic amine levels for dopamine, serotonin and octopamine. Foragers had higher levels of both dopamine and octopamine, and a higher octopamine to serotonin ratio than waste management workers. Patriline did not appear to have a strong direct effect on the levels of the biogenic amines, but did affect body size. The study has provided concrete data on how neurochemistry may play an important role in behaviour that is genetically determined. However, genetic effects on behavioural specialisation could be influenced by other factors.
Leaf-cutting ant, genotype, caste specialisation, patriline, neuromechanism, neurochemical, neuroanatomical, biogenic amine, dopamine, serotonin and octopamine