DIVERSITY OF CUTICULAR PROFILES IN EIGHT GENERA OF NEOTROPICAL SWARM-FOUNDING WASPS (HYMENOPTERA: VESPIDAE: EPIPONINI)
Lucas Amaral Oliveira, Lucas Amaral Oliveira , Fernando Barbosa Noll
Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), Ribeirão Preto, SP, Brasil; Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), Ribeirão Preto, SP, Brasil ; Departamento de Zoologia e Botânica, Instituto de Biociências, Letras e Ciências Exatas (IBILCE), Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP), São José do Rio Preto, SP, Brasil
Eusocial insects live in colonies in which their members interact in a great variety of contexts and coordinate activities for their survival and reproduction. Such colonial cohesion relies heavily on chemical communication through pheromones, especially cuticular hydrocarbons (CHCs). These compounds serve primarily as a barrier against water loss but also can act as short-range pheromones by encoding substantial information in species-specific chemical profiles. Unlike ants and bees, little is known about the CHCs mixtures diversity in the Neotropical swarm-founding wasps (tribe Epiponini), which typically form large colonies and exhibit complex social traits. Thus, our aim was to determine the CHCs profiles diversity in epiponine wasps. We sampled 10-20 adult female wasps from 14 spp. across eight genera (Agelaia, Apoica, Chartergellus, Parachartergus, Polybia, Protonectarina, Protopolybia and Synoeca) and determined the cuticular profile of each species by extracting in hexane a pool of the individual CHCs for GC-MS analysis. We also calculated a chemical diversity index (CD; based on Shannon-Wienner index) and a true diversity index [TD= exp(CD)] for each species. Altogether, we found 96 distinct peaks representing one or more compounds, predominantly n-alkanes, alkenes and methyl-branched alkanes with odd-numbered carbon chains. The C27 and C29 n-alkanes, the C31 methyl-branched alkanes, and the C22 alkenes were relatively abundant in most of the species. Ag. pallipes and Ap. pallens presented the most diverse cuticular profile (TD= 18 and 17, respectively) while Polybia spp. presented the least diverse cuticular profiles (TD≤ 5). Our findings suggest a tendency towards a chemodiversity loss from basal to more apical taxa in the tribe phylogeny. However, the inclusion of more taxa in our analysis from the remaining genera will provide a better scenario of how those pheromones have diversified in the Epiponini.