The Drosophila buzzatii Patterson & Wheeler cluster (repleta group) includes seven species: D. buzzatii Patterson & Wheeler, D. koepferae Fon

The West Indian fruit fly,Anastrepha obliqua, is an important agricultural pest in the New World. The use of pesticide-free methods to control invasive species such as this reinforces the search for genes potentially useful in their genetic control. Therefore, the study of chemosensory proteins involved with a range of responses to the chemical environment will help not only on the understanding of the species biology but may also help the development of environmentally friendly pest control strategies. Here we analyzed the expression patterns of three OBP genes,Obp19d_2,Obp56aandObp99c, across different phases ofA. obliquadevelopment byqPCR. In order to do so, we tested eight and identified three reference genes for data normalization,rpl17,rpl18andef1a, which displayed stability for the conditions here tested. All OBPs showed differential expression on adults and some differential expression among adult stages.Obp99chad an almost exclusive expression in males andObp56ashowed high expression in virgin females. Thereby, our results provide relevant data not only for other gene expression studies in this species, as well as for the search of candidate genes that may help in the development of new pest control strategies.

Conflict is thought to play a critical role in the evolution of social interactions by promoting diversity or driving accelerated evolution. However, despite our sophisticated understanding of how conflict shapes social traits, we have limited knowledge of how it impacts molecular evolution across the underlying social genes. Here we address this problem by analyzing the genome-wide impact of social interactions using genome sequences from 67Dictyostelium discoideumstrains. We find that social genes tend to exhibit enhanced polymorphism and accelerated evolution. However, these patterns are not consistent with conflict driven processes, but instead reflect relaxed purifying selection. This pattern is most likely explained by the conditional nature of social interactions, whereby selection on genes expressed only in social interactions is diluted by generations of inactivity. This dilution of selection by inactivity enhances the role of drift, leading to increased polymorphism and accelerated evolution, which we call the Red King process.