Meeting Abstract
16.3 Jan. 4 THE GEOGRAPHIC DISTRIBUTION OF MYTILUS GALLOPROVINCIALIS AND M. TROSSULUS IN NORTHERN JAPAN: THE POTENTIAL ROLE OF TEMPERATURE BRANNOCK, P M*; WETHEY, D S; HILBISH , T J; University of South Carolina brannockp@biol.sc.edu
The Mytilus edulis (common blue mussel) complex consists of three sister species (M. edulis, M. galloprovincialis, and M. trossulus) that are morphologically similar and capable of interbreeding when they co-occur. M. galloprovincialis has invaded a majority of the geographic locations where it is found today, while the other two species in this complex do not appear to invade or be as successful in their invasions as M. galloprovincialis. In 2004 a preliminary study utilized three nuclear loci (Glu-5�, MAL-I, and ITS) to observe the geographic distribution of M. galloprovincialis and M. trossulus around the island of Hokkaido. Results illustrated M. galloprovincialis dominates the Sea of Japan side of the island while M. trossulus is found on the eastern portion of Hokkaido. In addition, the level of hybridization in Hokkaido far exceeds that observed in other locations where M. galloprovincialis and M. trossulus hybridize. To determine if body temperature was correlated with distribution, average maximum and minimum body temperature for each month in 2004 were estimated with a mechanistic simulation model. M. trossulus genotypes were found only where yearly body temperature minimum was below 18°C, which restricts them to the eastern portion of Hokkaido. A more extensive study in the summer of 2006 examined individuals collected from 26 sites around the island of Hokkaido and 24 sites around the northern portion of the island of Honshu. Preliminary results from Glu-5� assay has shown the distribution pattern to remain the same. There is some hybridization on the east coast northern Honshu, but this level is very small compared to that found in Hokkaido. Future work includes assaying samples at the ITS and MAL-I loci and assessing the roles aerial and water temperature play in determining mussel body temperature and distribution.
