Eusociality is the main characteristc of social insects and it is one of the most remarkable transitions of evolution. Chemical communication acts as one of the most important channel that coordinates the dialogue among animals who live in societies. Division of reproductive labor segregates the individuals who live in colonies in two main groups, there are females who lay eggs (queens) and the rest known as workers who refrain from reproduction to perform the maintenance colonie labor (workers). Maintenance effectiveness of this system is due specificity chemical compounds productions released by queens (queens pheromones). It has been thought that one of the possible path could be through the eggs cuticle. Despite the existence of well stablished reproductive system between queens and workers, it has been seen that workers from some social insect species have ovarian development. However, worker eggs are policed by other worker, in other words, they are destroyed. Policing mechanism prevents colonies to have an over production of males and also ensures queen reproductive monopoly. Chemical information contained over the eggs are argue to exist, which help female recognition, and so far it is believed that could express honest signals of queen fertility. A probable hypothesis proposes that signals maintenance would be direct related with hormonal control, in other words, low quality females would not be able to product honest signals, taking into account that fertility and signals production would be interconnected. A plenty of works have demonstrated that in a several species of social insects there is a correlation in a presence of specific chemical compounds and queen fertility, it was also observed for common wasp (Vespula vulgaris) that queen cuticle pheromones are the same found across their eggs and that their cuticular hydrocarbons are under hormonal effect. These studies are punctual and require being formally tested trough bioassays for species of different social levels. Furthermore, through this project we will test the hypothesis that could exist a common signalization by pheromones which induces division of reproductive labor in wasps, which will contributes for the understanding about the use of alternative routes of communication, maintenance of honest signals and also the contribution of these signals for policing behavior. On this, we proposed three aims, one that basically would quantify the signals honesty released over the eggs and make some comparisons with signals on the queens and workers cuticle; the second would test whether the hypothesis of hormonal pleiotropy (endocrine regulation) indeed is applicable for social wasps system and finally whether this system helps for the policing behavior performed by workers in front of eggs laid by females previously treated with synthetic hormones. Part of this project will be developed in Brazil, by using solitary, primitively and eusocial species from Vespidae and solitary species from Crabronidae. Besides, another part might be developed in Belgium under supervision of Prof. Dr. Tom Wenseelers and Dra. Cintia Akemi Oi (in case BEPE is approved) and will include three species from Vespinae. The use and comparison of these different species will offer an extend idea about social behavior maintenance of insects. For this, packages of work will be conducted along the Ph.D. process. The three work packages will consist of behavior, physiology and chemical experiments. The results obtained will investigate whether the hormonal pleiotropy hypothesis for honest signals maintenance may be applied for wasps and also whether the eggs would acts as alternative vehicle for these signals spread.
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