Intraspecific variation of cuticular hydrocarbons and apolar compounds in the venom of Ectatomma brunneum

Abstract

By understanding the intraspecific differences of traits presented by a species, we can gain greater insight into their variable functionality in microevolutionary processes relative to genetic and environmental factors leading to ecological adaptation and speciation. However, few studies have evaluated how intraspecific variation of cuticle hydrocarbons (CHCs) occurs in relation to the apolar part of ant venom. Therefore, this study aimed to evaluate the chemical composition of compounds present in the cuticle and venom of different populations of Ectatomma brunneum ants. To accomplish this, 310 foragers from different populations were collected. Analysis of CHCs and the apolar part of the venom was performed using a gas chromatograph coupled to a mass spectrometer. Our results show that both the composition of CHCs and the apolar part of the venom vary significantly among the different populations. Differences in composition between the two types of compounds correlate with the geographic distance between the populations. In this sense, the greater the distance, the smaller is the gene flow between them. On the other hand, particular environmental conditions, such as temperature, humidity and available resources, leading to changes generated by adaptation, could be responsible for a part of these differences.