Linear Alkanes and Reproductive Status of Polistes versicolor (Hymenoptera: Vespidae) Females in Winter Aggregates

Abstract

Female wasps such as Polistes versicolor can form aggregates to face weather conditions that are not suitable to sustain their colonies. The interactions between individuals in these aggregates, just as in other associations, are probably facilitated by chemical signals. Of these compounds some of the most efficient during social interactions of insects are those called contact pheromones or superficial pheromones. This special type of pheromones, known as cuticular hydrocarbons, can be found in insects cuticle. They facilitate the differentiation of caste, species and nestmates, and may be important indicators of dominance as well as fertility. Some studies indicate that linear alkanes are important cuticular compounds for intraspecific recognition and discrimination. The aim of this study was to evaluate the relationship between reproductive physiologic condition and the linear alkanes present in the cuticle of females of P. versicolor in aggregates employing Gas Chromatography with Flame Ionization Detector (GC-FID). Females from distinct aggregates were differentiated by the chemical composition of their cuticle. In each aggregate, there was difference in cuticular chemical composition between females with different ovarian development degrees, allowing the distinction between inseminated and non-inseminated females.

Discrimination of Diptera order insects based on their saturated cuticular hydrocarbon content using a new microextraction procedure and chromatographic analysis

“…Very interesting results were obtained for intra- and inter-species differentiation by focusing only on linear alkanes, in line with previous work 12,13,23 and in contrast to other studies considering other groups of compounds such as alkenes. 7,15,17,21,22 The statistical treatment of the SCHC levels in the Diptera order specimens allowed the differentiation of several species, as well as the observation of segregation groups according to their development stage or growth pattern.…”

“…GC is the most widely employed instrumental technique for CHC determination combined with ame ionization detection (FID) 8,23 and mass spectrometry (MS), 4,9,16,25 and in some cases both (GC-FID and GC-MS) are used in a complementary way. 5,11,33,34 The application of statistical analyses is also shown in the literature.…”

“…7,11,15,17,21,22 However, in some cases the discriminatory capacity has been addressed by considering only the saturated cuticular hydrocarbon composition (SCHC). 12,13,23…”

“…7,11,15,17,21,22 However, in some cases the discriminatory capacity has been addressed by considering only the saturated cuticular hydrocarbon composition (SCHC). 12,13,23 The sample treatment commonly used for the determination of CHCs in insects consists of solid-liquid extraction (SLE) in hexane, 3,4,6,7,9,17,21,22,24 followed by a purication step using a silica gel column 6,9,17,21 or activated magnesium silicate. 3,22 Preconcentration is generally carried out by solvent evaporation and reconstitution of the dry residue in a lower volume of the solvent.…”