Variations in the Cuticular Chemical Profile of the Ant Ectatomma brunneum Smith, F. 1858 (Formicidae: Ectatomminae) Across Different Biomes in Brazil

The insect cuticle is composed of chemical compounds that evolved to prevent desiccation and provide defense against pathogens. These compounds were subsequently co-opted for chemical communication and, in social insects, are crucial for nestmate recognition and caste discrimination. Several factors can influence the cuticular chemical composition, making it a good biogeographical study tool, since it varies among populations, according to genetic and environmental factors. The use of cuticular compounds in studies of the social Hymenoptera is important for understanding the influence of the environment on the distribution and occurrence of species. This study aimed to determine whether environmental factors might be decisive in determining the cuticular chemical profiles of colonies of the ant Ectatomma brunneum (Smith). Samples were collected in different biomes of Brazil, for analysis using Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS). Similarly to other phenotypic characteristics, the cuticular chemical profile varied significantly among populations, confirming its potential as a tool to assess biogeographical differences. Furthermore, environmental factors were important determinants of the cuticular composition of this species of ant.