My name is Sarah (Sally) Bornbusch and my project explores the evolutionary and ecological origins of a unique social behavior in a genus of marine shrimp. The genus Synalpheus is a wide spread group containing over 100 species of marine coral-reef shrimp and some of these species display a complex social structure known as eusociality, a characteristic unique among marine organisms. Eusociality is considered one of the highest form of community organization in the natural world. It is defined as a social system with reproductive division of labor in which there is cooperative brood-care throughout the colony. The colonies are often composed of only one reproducing female, known as the queen, as well as hundreds of individuals such as males, non-reproducing females, and juveniles. These individuals are often divided into castes such as workers or guards. Most commonly found in insect groups such as bees and ants, eusociality has been identified in very diverse taxa with varying environmental factors. In addition it has been found to have evolved separately at least 3 times within the Synalpheus genus alone. Because of this, Synalpheus has become a model system for the study of complex social organization in organisms. The focus of my project is on the reproductive periodicity of these social colonies; an important characteristic in determining how these social colonies arise in addition to their dispersal and survival potential.
My focus will be on the Synalpheus reproductive cycle, which is poorly understood. The
timing, seasonality, and method of reproduction will provide insight into both the inter and intra specific
relationships of this genus. Key questions I will focus on include whether colonies of the same species
in similar geographical regions reproduce simultaneously, indicating a kind of mass spawning event
correlated with season or lunar phase, or whether related species reproduce at similar times, possibly
indicating a phylogenetic characteristic to breeding. These questions will take into account the
geographical, ecological, and phylogenetic factors of each group.
In order to answer these questions I will be working in the VIMS Marine Biodiversity Lab full-time for the coming summer as well as into my senior year. This lab work will consist of specimen sorting and analyzing as well as entering the specimens into a comprehensive electronic database which will allow me, VIMS, and other researchers around the world to identify patterns and investigate further questions. I will also travel to the Dominican Republic and/or Belize to collect shrimp and sponges and take measurements on many of the ecological factors that could be influencing eusociality.