Current and Past Researchers at BFL
In a paper published in Science in 1975 William Cade showed that a species of parasitoid fly orients to the calls of calling male crickets, deposit their larvae on the flies, and the larvae then consumes the cricket. This was one of the first demonstrations of the costs of sexual signalling in any animal. Cade after a career at Brock University, is currently president of Lethbridge University in Canada. Scientists influenced by Cade’s study still come to BFL to study cricket fly interaction, and novel hearing aid designs have been inspired by the fly’s auditory mechanism.
In the late 1970's grad student Don Feener , now Professor at the University of Utah, discovered that phorid fly parasites of Pheiodole ants reversed the outcome of their competition with other ant species. The results, published in the journal Science in 1981, not only was the first clear demonstration of indirect effects in ecology, now a hot topic, but that basic result stimulated later application of the concept to biological control of imported fire ant.
In paper published in 2002, Proc Royal Society, graduate student Natasha Mehdiabadi, working with L.E. Gilbert, reported on controlled experiments to explore the relative impact of phorid flies and competing ants on fitness of fire ant colonies. She demonstrated that harassment by the flies may reduce colony intake of food by 50% supporting the idea of indirect rather than direct impact of these flies on flre ants.
In a paper published in Science in 1987, William Wagner, together with his sponsor M.J. Ryan, showed that in the swordtail fish, Xiphophorus pygmaeus, males lose the allele of a gene that is responsible for large body size, resulting in a species of all pygymy males. The females, however, retain their preference for large males despite the loss of all these males from the species. This was one of the first studies to show how male traits and female preferences for traits can be decoupled during evolution. Wagner is an Associate Professor at the University of Nebraska.
In a paper published in Science in 1994, Ingo Schlupp and Cathy Marler , together with their sponsor M.J. Ryan, showed that when males of a sexual species of fish, the sailfin molly, mate with an asexual species, the Amazon molly, the males make themselves more attractive to their own females who are watching their dalliances. This was one of the early, critical contributions to the field of mate-choice copying, which has even found its way into studies of human mating behavior. Cathy Marler is a Professor at the University of Wisconsin, and Ingo Schlupp is an Associate Professor at the University of Oklahoma.
Then graduate student, Joan Strassmann studied a paper wasp, P. exclamans at BFL. She showed that relatedness matters when ecological conditions are held constant. Workers and queens made satellite nests. Other workers freely joined the queen satellites, but only joined the worker satellites when their mother the queen had been replaced on the main nest. So, other things equal, they joined the satellite in numbers. If relatedness was not equal they did not join it. This test of kin selection theory propelled Strassmann to a prominent career in social evolution. She is now Wiess Professor and Department Chair of Ecology and Evolutionary Biology, at Rice University.
Graduate student Nancy Burley's study of mate choice in pigeons at BFL successfully tested major predictions of sexual selection theory. Published in PNAS in 1977, this work initiated a prominent career in evolutionary animal behavior. Burley is currently a Professor at UC Irvine. Helping Burley at BFL was undergraduate Nancy Moran getting her first taste of research Moran, now Professor at U of Arizona, is a member of the National Academy of sciences, famous for work on the genomics of aphid endosymbionts that supply aphids with many essential nutrients.
Greg Sword's discovery of a color changing grasshopper at BFL helped solve an ancient mystery about one of the world's most notorious agricultural pests, the Desert locust of Africa and the Middle East, whose plagues have been documented in the Bible. Sword showed that some grasshoppers and locusts can become brightly colored as a signal that they are toxic and should be avoided by their predators. His work at BFL was published in the premier science journal, Nature, and set the stage for a series of subsequent studies that have made major contributions to understanding locust ecology around the world. Sword received his PhD from the University of Texas and has since held positions at Oxford University, the USDA and the University of Sydney.
Ken Whitney (Rice University) has been studying the impact of plant hybridization on rates of adaptation and phenotypic change in wild sunflowers. This is the first experimental field study to examine the impact of hybridization on adaptive evolution over multiple generations in a non-crop system. Evolutionary change is measured and compared in hybrid and non-hybrid populations across central and eastern Texas, including populations at the Brackenridge Field Laboratory. The work published in American Naturalist 2006,has demonstrated that natural hybridization can increase evolutionary novelty and transfer adaptive traits between species.
Undergraduate, Bill Van Eimerin , directed by L.E. Gilbert , initiated a detailed study of the invasion of BFL by imported fire ant in 1983. Continued by Postdoctoral researcher, Sanford Porter and Gilbert, it became the first study to reveal the mechanism of competitive replacement of native ants. The study led to further research on the ecological impacts of fire ant invasion published in Ecology and the first demonstration, by post docs E. Vargo and S Porter of how multi queen fire ants reproduce by budding.
Porter now directs USDA ARS efforts in fire ant biocontrol in Gainesville Fla and Vargo is Professor of Entomology at NC State University.
In a series of studies since 2006, the Invasive Species Research group led by Larry Gilbert, Rob Plowes and Ed Lebrun, have made fundamental advances in invasion biology showing why some systems resist invasion by fire ants, and have also used phorid flies introduced to control fire ants as a model system to understand invasion dynamics. Recent work includes studies of Nylanderia crazy ants, exotic grasses that have altered the fire regimes, and cactus-feeding moths.