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Recognizing the predominant mode of selection in hybrid systems is important in predicting the evolutionary fate of recombinant genotypes. Natural selection is endogenous if hybrid genotypes are at a disadvantage relative to parental species independent of environment. Alternatively, relative fitness can vary in response to environmental variation(More)
Polyphenism, which allows a single genotype to express multiple discrete phenotypes in response to environmental cues, is an adaptive trait in heterogeneous environments. Pond hydroperiod is an important ecological parameter affecting amphibian life history, and variation in local pond hydrology has been hypothesized to play a role in species divergence via(More)
Despite ecologists increasingly recognizing pathogens as playing significant roles in community dynamics, few experimental studies have quantified patterns of disease impacts on natural systems. Amphibians are experiencing population declines, and a fungal pathogen ( Batrachochytrium dendrobatidis; Chytridiomycota) is a suspected causal agent in many(More)
The immune system is a necessary, but potentially costly, defense against infectious diseases. When nutrition is limited, immune activity may consume a significant amount of an organism’s energy budget. Levels of dietary protein affect immune system function; high levels can enhance disease resistance. We exposed southern leopard frog [Lithobates(More)
Pathogen-induced modifications in host behavior, including alterations in foraging behavior or foraging efficiency, can compromise host fitness by reducing growth and development. Chytridiomycosis is an infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis (Bd), and it has played an important role in the worldwide decline of(More)
Distinguishing whether pathogens are novel or endemic is critical for controlling emerging infectious diseases, an increasing threat to wildlife and human health. To test the endemic vs. novel pathogen hypothesis, we present a unique analysis of intraspecific host-pathogen phylogenetic concordance of tiger salamanders and an emerging Ranavirus throughout(More)
As resources grow scarcer , universities have become reluctant to increase the long-term institutional commitments involved in faculty appointments with tenure. The restrict tenured appointments, universities in recent years have adopted more stringent criteria for approving them and in many cases have set a limit on the number of new appointments and(More)
Pathogens can alter host life-history traits by affecting host feeding activities. In anuran tadpoles, keratinized mouthparts (teeth and jaw sheaths) are essential for feeding. Batrachochytrium dendrobatidis ( Bd ) is a pathogenic fungus of amphibians that can infect these mouthparts and reduce tadpole survival. However, the precise way that Bd-induced(More)
Amphibian species face the growing threat of extinction due to the emerging fungal pathogen Batrachochytrium dendrobatidis, which causes the disease chytridiomycosis. Antimicrobial peptides (AMPs) produced in granular glands of the skin are an important defense against this pathogen. Little is known about the ontogeny of AMP production or the impact of AMPs(More)
Differences in host behavior and resistance to disease can influence the outcome of host-pathogen interactions. We capitalized on the variation in aggregation behavior of Fowler's toads (Anaxyrus [ = Bufo] fowleri) and grey treefrogs (Hyla versicolor) tadpoles and tested for differences in transmission of Batrachochytrium dendrobatidis (Bd) and(More)