Does parasitism drive differential neurogenomic expression in females and males of a Polistes paper wasp?

Abstract

Host-parasite interactions represent a widespread coevolutionary example in nature, with parasitism consisting of a selective force towards exploiting a host. Parasites induce mild to dramatic changes over their hosts, which in turn results in affecting the host's fitness. The behavioral and physiological effects of parasitic manipulation are well-studied. However, much less is known about the molecular mechanisms underlying parasitism, such as host gene expression. A well-studied host-parasite system is composed by the endoparasite strepsipteran Xenos and the paper wasp Polistes. In this complex system, parasites affect their hosts in different ways depending on both host and parasite sex. Parasitized female hosts are castrated and become asocial, whereas male hosts remain sexually interested in females and can still mate, regardless of parasites presence. The fact that female and male hosts are not affected in the same way suggests that parasitic manipulation may vary in different phenotypes of the same species (i.e. host sex) Importantly, males and female parasite vary in how they manipulate the host to increase their chances of fitness. A male parasite only needs a host for a few weeks, to develop and emerge as an adult to mate in the summer. In contrast, female parasites remain as obligate parasites inside their host for many months to secure release of offspring in the next Spring. Thus, we will take advantage of the parasite Xenos peckii and its wasp host Polistes fuscatus to explore whether parasites have differential effects in gene expression according to both parasite and host sex. Specifically, we will compare transcriptomic profiles of female and male hosts infected by female and male parasites. These data will allow us to check which genes and their levels of expression related to reproductive, endocrine and social traits are affected by parasites. Our results will allow us to elucidate differential gene expression and candidate genes that likely suppress the immune system of their host, and mechanisms of manipulation. Considering that parasitized and unparasitized individuals were already sampled, this work will consist of four parts (I) learn the procedures to dissect brains followed by RNA extractions, (II) RNA sequencing, (III) performing gene expression analysis, and (IV) writing a manuscript. (AU)