The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support a twenty-four-month research fellowship by Dr. Shawn R. Kuchta to work with Dr. Erik Svensson at Lund University in Lund, Sweden.
In natural systems, individuals must avoid being eaten if they are to pass their genes on to future generations. For this reason, predation has a strong impact on organismal fitness. The selective consequences of predation are difficult to study, however, because predation removes individuals from the population and thereby prevents their measurement. Studying the geographic structure of predation intensities is even more difficult. In collaboration with Erik Svensson at Lund University in southern Sweden, this research addresses the geographic mosaic of selection gradients imposed on damselflies (Calopteryx) by an efficient avian predator, the wagtail. Wagtails catch damselflies and return to "slaughter stations" where they remove the wings and consume the body. Collecting wings from slaughter stations and comparing them to the variation present in natural populations allows us to calculate the strength and direction of natural selection on various wing traits, such as the shape and size of color patches. Prior research has demonstrated natural selection on wing traits in one population, but the current research extends this to 22 populations, including "hotspots" and "coldspots" of predation intensity. In addition, high resolution molecular markers are being used to measure the amount of genetic exchange among populations. This data allows us to quantify the interaction between local adaptation within populations versus gene flow among populations with differing adaptive optima. In addition to influencing predation probabilities, color patches on the wings of damselflies function in female choice (sexual selection) and species recognition (visual clues different species employ tell each other apart). The trade-off among the various selective forces is being examined by manipulating the wing patch size in natural populations of damselflies and simultaneously measuring the magnitude of natural selection, sexual selection, and interspecific interactions. This experiment is being replicated in four populations, including two "hotspots" and two "coldspots" of predation intensity. Predator-prey dynamics are of profound importance to the dynamics of natural systems. This research takes an integrative, spatially explicit approach to advancing our understanding of the ongoing selective processes operating in natural populations.
