Mutualistic associations between bobtail squids and their luminescent bacterial symbionts (genus Vibrio) make excellent models to study the evolution of animal-acterial associations. Since symbiotic bacteria are transmitted through the surrounding seawater to new hosts with every tion, it provides a uniqe opportunity to resolve how the ecology of free-living bacteria effects the make-up of these squid-luminous bacterial partnerships, particularly with respect to factors such as salinity and temperature. Since Vibrio bacteria are quite easily adaptable to changing environmental conditions, this may lead to the possibility of range expansion of these bacteria to different squid populations, and may eventually lead to the evolution of new species of Vibrio. This proposal will examine both free-living and symbiotic vibrios under a variety of conditions in the laboratory (salinity, temperature) to determine if abiotic factors contribute to the distribution of Vibrio among wide ranging host populations. Simultaneously, monitor genetic changes of various Vibrio bacteria in different squid host species will be monitered in the lab to determine if the host has any influence upon Vibrio evolution. These experiments will be completed via growth studies of the bacteria in culture or in juvenile squids that are raised in the laboratory. Clearly, there is a need to understand how quickly organisms such as bacteria can adapt to different environments; with the noticeable change in global climate, it will be a benefit to determine if these changes will increase or decrease biodiversity on a much larger scale. The expected outcome of this research is that adaptation occurs at a much higher frequency due to fluctuations in the environment, which then allows successful colonization of different host species, providing a new trajectory for bacterial speciation to occur. Results from this proposal will be disseminated through publications, teaching, web sites, and outreach to have a greater impact for both the public and research communities.
