Field Talk » University

Battles of the sexes: Competition and evolution in tropical hummingbirds

liza — Thu, 28 May 2009 21:07:59 +0000

In this edition of Field Talk, we catch up with Ethan Temeles, a biologist at Amherst College, who tells us a tale of competition among the sexes in Caribbean hummingbirds – competition so severe that it drives their evolution. The short, straight bills of male purple-throated caribs and the long, curved bills of female caribs correspond to the shape of heliconia flowers on which they feed. The story got more complicated, though, when Dr. Temeles and his students discovered that despite their curved bills, females prefer straight flowers to curved ones. Join us as Dr. Temeles explains how this species’ sexual dimorphism evolved, and read more in his paper in the May issue of Ecology.

Lizard Evolution and the Ants In Your Pants Dance

liza — Mon, 26 Jan 2009 22:29:52 +0000

Invasive red fire ants from South America have become a major pest in southwestern U.S., bringing their stinging venom and crop-destroying ways. In this edition of Field Talk, we catch up with Tracy Langkilde, assistant professor of biology at Penn State University, who studies one of the ants’ seemingly unlikely targets: eastern fence lizards. The lizards have evolved a novel twitching response that flicks attacking ants off their bodies. But in her paper in the January issue of Ecology, Dr. Langkilde explains that since native ants don’t normally attack lizards, this behavior must have evolved in a very short time.

Candy canes as plant defenses

liza — Mon, 22 Dec 2008 21:47:15 +0000

What would make a plant want to stop growing towards the sun and instead grow downward? Michael Wise of the University of Virginia studies a species of goldenrod that grows toward the ground for part of the spring months, creating a morphology that looks a lot like a candy cane. He explains that this “candy-cane” morphology could increase the plant’s defenses against herbivores. The origin and evolution of such a defense, however, is a mystery when so few plants disguise themselves by this morphology, which he likens to an animal ducking to escape a threat. Read more about Wise’s research in the December issue of Ecology (www.esajournals.org/doi/abs/10.1890/08-0277.1).

To fly or not to fly? Diving birds shun air travel

liza — Tue, 18 Nov 2008 17:22:28 +0000

The ability to fly is one of the most significant adaptations in animal history. Some birds, however, have opted out of flying – evolutionarily speaking. In this installment of Field Talk, we catch up with Dr. Rory Wilson, a professor of aquatic biology at the University of Swansea. His paper in the November issue of Ecological Monographs examines the Galápagos cormorant, an aquatic bird that hunts seafloor prey off the coasts of the islands where it makes its home. Wilson and his colleagues find that the peculiar conditions on and around the islands has led to the loss of flight in these cormorants, a trade-off that gives these birds better diving ability.

Dead Zones as Safe Havens

liza — Fri, 10 Oct 2008 14:39:18 +0000

Andrew Altieri, a postdoctoral fellow at Brown University, joins us in this month’s episode of Field Talk to discuss his work examining hypoxic marine systems, known as dead zones. Altieri studies a community of clams and mussels – collectively known as bivalves – in Narragansett Bay, off the coast of Providence, Rhode Island. His paper in the October issue of Ecology shows that one species of bivalve, the quahog, can benefit from reduced oxygen content in the water. The resulting boom in quahog populations has important implications for ecosystem services.