Collaborative Research: RUI: Uncovering eusocial pathways and consequences: Phylogenomics, morphological, and molecular evolution in Synalpheus snapping shrimps.

Typified by obligate group living and reproductive division of labor, eusocial behavior is considered the apex of animal social organization. Within a eusocial colony, a single or subset of individuals (queens) perform all reproductive duties while others (workers) forgo their own reproduction and undertake tasks related to brood care, nest maintenance, or resource acquisition. This profound and ecologically impactful behavioral transition has arisen at least 19 times in animals. Remarkably, nearly one fourth of known evolutionary origins of eusociality have occurred within a genus of sponge-dwelling snapping shrimps called Synalpheus. However, why and how eusociality evolved in these aquatic animals remains unclear and the answers to these questions may reveal potential universal requirements or consequences relating to advanced social complexity. This project seeks to reconstruct the evolutionary relationships between species in this genus to identify morphological and genomic changes that are associated with the transitions to advanced sociality. The project will generate open access resources that will be used to test potentially universal “laws” related to social evolution across animal lineages. The project will also support numerous research opportunities for undergraduate students as well as educational content for K-12 schools and web-based channels. The project will generate genomic and phenotypic data spanning about 130 species of Synalpheus snapping shrimps worldwide. These data will be used to 1) reconstruct a dated phylogeny of Synalpheus taxa using phylogenomic methods; 2) evaluate the relationship between eusociality and molecular evolution; and 3) recover morphological preadaptations and consequences of eusociality. Genomic data will be sequenced through targeted enrichment of previously published and newly developed probe sets. Morphological data will be generated through traditional microscopy and X-ray based micro-CT-scanning of closely related species spanning different social organizations. Both genomic and phenotypic data will be analyzed using phylogenetic comparative methods enabled with initial phylogenetic products. Project activities will identify patterns of molecular evolution between eusocial and non-eusocial species to test hypotheses suggesting that social organization affects rates of molecular evolution via demographic effects such as reduced effective population sizes and increased generation time. Through 3D morphometric analyses, the project will work to uncover morphological preadaptations to eusocial origins, impacts of social behavior on morphological evolution, and putatively contingent or deterministic pathways toward convergent phenotypic syndromes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.