Sexual selection, natural selection and the evolution of dimorphic coloration and ornamentation in agamid lizards by Dr DM Stuart-Fox and Dr TJ Ord
Conspicuous coloration and ornamentation in males are thought to result from sexual selection. However, these 'showy' traits can also incur increased predation risk. We examined the trade-off between sexual selection and natural selection in dragon lizards. Our results reveal that in species occupying closed habitats, both sexes are ornamented and males are more conspicuously coloured than females. In contrast, species occupying open habitats tend to be less ornamented and males tend to be conspicuously coloured only on body regions that can be concealed from predators. Natural selection from predators therefore constrains the evolution of sexually selected traits in dragon lizards.
Contact: Dr Terry Ord, Department of Biology, Indiana University, 1001 East 3rd Street, Jordan Hall 142, BLOOMINGTON, IN 47405, USA
A temporal analysis shows major histocompatibility complex loci in the Scandinavian wolf population are consistent with neutral evolution by Dr JM Seddon and Professor H Ellegren
The major histocompatibility complex (MHC) has an integral role in the immune system and the high levels of variability found among its genes may be of particular importance for the health of populations. We examined the level of diversity at three MHC class II loci in the wolf population of Scandinavia, a population naturally recolonised with a genetic contribution from as few as three founders, and in four neighbouring wolf populations. The bottlenecks and fragmentation noted in wolf populations in Europe have resulted in a lack of selective forces that would otherwise be expected to maintain high level of variation.
Contact: Dr Jennifer Seddon, School of Veterinary Science, University of Queensland, St Lucia QLD 4072, Australia
Contact: Tim Watson