Neural plasticity in the brain of workers of the carpenter ant Camponotus rufipes (Hymenoptera: Formicidae)

The plasticity of the nervous system results from experience, age, sex and endocrine status and it is evidenced during adult life by changes in behavior. This work studied the structural changes in the brains of polymorphic workers of the ant Camponotus rufipes. Behavioral patterns were analyzed, in order to assess their possible relationship to changes in the brain volume. Results showed the occurrence of neuroplasticity during the adult stages. The behavioral effects on the brain volume differed mainly in the minor workers. Minor workers that are three days old have large brain volume, but in seven-day-oldworkers the brain volume decreases. However, in the 45-day-old major workers the absence of behavioral patterns does not suggest any relationship with the brain volume, bringing doubts on the influence of behavior on the brain plasticity. Neuropile volumes of worker subcastes are affected by age, suggesting an increase in neuronal branches and possible synaptic activities, in response to information processed during the ant life span.