Effect of Seasonal Variation on the Cuticular Chemical Composition of Atta laevigata (Smith 1858) (Hymenoptera: Formicidae).

Abstract

Cuticular hydrocarbons (CHCs) constitute an important class of chemical compounds present in the cuticular layer of insects, where their main functions are to prevent desiccation of the cuticle and as signals for intraspecific recognition. Studies concerning CHCs have shown a phenotypic flexibility of their composition, depending on environmental factors. However, the way that each of these factors influences this variation remains little explored. The aim of the present study was to evaluate the effects of environmental variations on the cuticular chemical composition of the ant Atta laevigata. Workers from four different colonies nesting in forest edge environments were collected over the course of a year, during the hot and humid and cold and dry seasons. The cuticular compounds were extracted and then analyzed by gas chromatography, revealing that the compounds of this species belonged to the classes of linear alkanes, mono, di and trimethyl alkanes, alkenes and alkadienes. Furthermore, the cuticular profile varied significantly among colonies of this species and between seasons, while intra-season variability was more significant during the hot and humid season. The observed temporal variation indicated that the numbers of compounds and the proportion of different types of CHC can vary according to the period of the year, however with a greater significant variation in colonies in the hot and humid season. These results showed that variations in environmental conditions, especially climate, can have decisive effects in the dynamics of cuticular chemistry.