Like some coevolutionary SWAT team, John Thompson, Bradley Cunningham, and colleagues have headed out every spring and summer for the last decade to the wilds of western Idaho and bordering areas in Oregon and Washington to camp out and infiltrate the world of the prairie starflower, Lithophragma parviflorum, and a little gray moth known as Greya politella. Now, their published rare case study in coevolution describes how the two species have coevolved in a variety of habitats, from open grassland to ponderosa pine woodland and streamside canyons.1 The paper presents a glimpse into how species interactions evolve and the impact those interactions have.
As with most relationships, this one between moth and flower proved to be sometimes mutually beneficial, sometimes ambivalent, and sometimes downright antagonistic, depending on their locations. Although the coevolutionary hotspots and coldspots the Cunningham-Thompson teams traversed represented only part of the range of the two species, they found significant variation in coevolutionary selection pressures across a broad area. This variation "may be an important factor shaping the genetic structure of species and the ecological dynamics of natural communities," says Thompson, professor of ecology and evolutionary biology at University of California, Santa Cruz. "Selection really can push populations in different ways and in different places."
The work by Thompson and Cunningham, of the School of Biological Sciences at Washington State University in Pullman, offers insights for future biodiversity conservation. "We're finding that much of evolution is about coevolution of species, how species continually respond to one another, forming complex networks of interaction," says Thompson. "If keeping players in the evolutionary game demands a geographic mosaic of coevolutionary hotspots and coldspots, then fragmentation of habitats will fundamentally change the way coevolution maintains biodiversity--and we're not going to solve things by having solutions that only conserve single populations. This study, which is a sort of bridge between single-species and ecosystems approaches to environmental research, suggests that we need to look at larger scales to understand how coevolution shapes biodiversity."
"We need to build more bridges and we need to be building very rapid evolution into conservation policy, because we now know populations of species are evolving fairly rapidly." And, Thompson adds, "No time is too early to start."
A.J.S. Rayl (ajsrayl@DIRECTVInternet.com) is a contributing editor.