Reinforcement is the process by which reduced hybrid fitness generates selection favoring the evolution of stronger prezygotic reproductive barriers between emerging species. Using common-garden field experiments, we quantified the strength of reinforcing selection in nature by demonstrating strong selection favoring an allele conferring increased pigment intensity in the plant Phlox drummondii...

Niche theory in its various forms is based on those environmental factors that permit species persistence, but less work has focused on defining the extent, or size, of a species' environment: the area that explains a species' presence at a point in space. We proposed that this habitat extent is identifiable from a characteristic scale of habitat selection, the spatial scale at which habitat be...

Despite the unprecedented development in identification and characterization of prophenoloxidase (proPO) in commercially important decapods, little is known about the evolutionary relationship, rate of amino acid replacement and differential selection pressures operating on proPO of different species of decapods. Here we report the evolutionary relationship among these nine decapod species base...

The coevolution of interacting species can lead to codependent mutualists. Little is known about the effect of selection on partners within verses apart from the association. Here, we determined the effect of selection on bacteria (Xenorhabdus nematophila) both within and apart from its mutualistic partner (a nematode, Steinernema carpocapsae). In nature, the two species cooperatively infect an...

Estimates of the fraction of nucleotide substitutions driven by positive selection vary widely across different species. Accounting for different estimates of positive selection has been difficult, in part because selection on polymorphism within a species is known to obscure a signal of positive selection among species. While methods have been developed to control for the confounding effects o...

In order to obtain an optimum management of natural resources, determination of variables that control plant presence and distribution is needed. In the present research, the relationship between some character plants of drylands and some soil and environmental variables were investigated. After primary survey and selection of main plant species, sampling was done in each vegetation type within...