Symbiosis is an integral part of life. From the bees that pollinate plants to the chytrid fungus decimating amphibian populations, most life on Earth is engaged in symbiotic interactions ranging from mutualistic to parasitic. Crayfish and their ectosymbiotic annelid worms (Order: Branchiobdellida) engage in a density-dependent cleaning symbiosis that shifts between a mutualism and a parasitism. This shift provides us with an effective tool to study the nature of symbioses. Our current work utilizes metacommunity theory, which describes the interactions between spatially disparate communities of organisms, to model and predict these symbiotic associations. A metacommunity is a community of communities, groups of interacting organisms that affect each other through dispersal. Traditionally, this framework has been used to study communities along connected environmental patches. However, if we consider a host crayfish to be a patch, we can use this framework to explore the assembly and structure of symbiotic communities. It has been shown that habitat age has a profound influence on the assembly of traditional metacommunities, with higher richness at patches of intermediate age. When a host crayfish molts, we can use the disturbance to apply this concept to a symbiotic metacommunity.
Results/Conclusions
We surveyed the crayfish and worm communities at Sinking Creek in Newport, VA from March 2017 until February 2018. This study has provided us with insights into how the worm communities develop on each crayfish after a disturbance event by looking at crayfish molting. Previous literature indicated that a crayfish loses 75% of its worm community when it molts, and our results show a reduction in abundance as well. Additionally, our results have shown that the worm communities on larger, recently molted crayfish more closely resemble the less diverse communities on smaller crayfish. Most worms on recently molted crayfish are ones that we know are early colonizers. This would suggest that molting acts as a disturbance to the worm community, and that time since molt can be used as a proxy for patch age. These data are evidence of the opportunity to use the inference space provided by the metacommunity framework to explore the dynamics of symbiotic communities.