David B. Carlon
Population Biology, Adaptation, Speciation
I use molecular, experimental, and comparative approaches to probe questions related to the structure, dynamics, and evolution of marine populations. I am particularly interested in the life-history of speciation: from ancestral population to the evolution of isolating mechanisms that limit gene flow between new species. We study a variety of charismatic meso- and mega-fauna in my lab, including corals, hermit crabs, urchins, parrotfish, and… seabirds. Two currently funded projects are described below. Consult my lab website for more details on me, my students, and what we do.
1. A multidisciplinary approach to species boundaries in tropical reef corals
How new species form remains a classic and challenging question in evolutionary biology. We are using ecological, morphological, and molecular approaches to understand how reproductive isolation evolves, and the permeability of species boundaries to gene flow. This latter question is controversial among coral biologists, as species-level phylogenies based on morphology do not always agree with the increasing number of molecular data sets. At the population level, we are using an "incipient" speciation event between two forms of Favia fragum (photos, right) to test a model of ecological speciation. We are also addressing the long-term permeability of species boundaries by using morphological and molecular data sets to fit models that permit gene flow between species after an initial barrier to reproduction forms. This work is currently funded by a NSF DEB grant.
2. The genetic structure of keystone species on Pacific coral reefs
The community structure of many coral reefs has been strongly impacted by the loss of grazers because of overfishing. Conservation of key functional groups of coral reef grazers requires an understanding of the number and boundaries of unique populations within keystone species' biogeographic range. We are using microsatellite markers and Bayesian models to understand the population structure of two broadly distributed reef grazers: the Collector urchin Tripneustes gratilla and the Ember parrotfish Scarus rubroviolaceus. These projects are motivated by conservation here in Hawaii, but our broad sampling across the Pacific and Indian Oceans is revealing hotspots of molecular and phenotypic differentiation that shed light on the geography of speciation. This research has been supported by Seagrant and the Hawaiian Coral Reef Initiative.
Bailey-Brock, J.H., Magalhães, W.F. & Brock, R.E. 2012. Coral reef inhabiting tubeworms (Polychaeta: Serpulidae) from Enewetak, Kwajalein, Rongelap and Utirik Atolls, Marshall Islands. Journal of the Marine Biological Association of the UK. in press.
Magalhães, W.F. & Bailey-Brock, J.H. 2011. A new species of Acrocirrus Grube, 1872 (Polychaeta: Acrocirridae) from Coconut Island, Oahu, Hawaii. Journal of the Marine Biological Association of the UK. Doi: 10.1017/Soo 25315411000634.
Bailey-Brock, J.H. and W. Magalhães. 2012. A new species and record of Serpulidae (Annelida: Polychaeta) from Cross Seamount in the Hawaiian Chain. Zootaxa. Online.