A team of scientists has discovered that descendants of "exploratory" butterflies that colonized new habitats differ genetically from their more cautious cousins. The team, led by James Marden, a professor of biology at Penn State University, and Christopher Wheat, a post-doctoral scholar working at both Penn State and the University of Helsinki, has revealed some of the genetic bases for faster egg maturation, a higher rate of energy metabolism, and superior flight ability -- traits that provide an advantage to butterflies that stray from familiar territory to found new populations in previously unoccupied habitat patches. The results have potentially broad importance because they show how natural selection may act in species that occupy spatially distinct habitat patches. This research will be published in the print edition of the journal Molecular Ecology in May, and is available in early-online form at <http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2011.05062.x/full>.
Marden explained that most species are not found everywhere because they tend to require very specific habitats. "Butterflies, like many other species, are specialists. They are picky about where they live. This pickiness gives a species what ecologists call a clumped or patchy distribution," Marden said. "In a patchy environment, individual organisms face a fundamental choice between remaining in their native patch or venturing forth to find a different patch of suitable habitat. Staying put is safer for immediate survival but may expose one's offspring to crowding or parasites, whereas dispersal is dangerous but offers a potentially big payoff if a large, unoccupied patch is located."
Marden and Wheat collaborated with Ilkka Hanski, a professor at the University of Helsinki, to study how a particular species of butterfly successfully establishes new populations. "We wante
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