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We document a strong association between predation environment and life-history phenotypes in the Costa Rican livebearing fish Brachyrhaphis rhabdophora. Populations that co-occurred with piscine predators attained maturity at a smaller size, and produced more, smaller offspring relative to populations from predator-free environments. These differences(More)
We suggest that the ultimate outcome of interactions between native species and invasive species (extinction or coexistence) depends on the number of simultaneous negative interactions (competition and predation), which depends on relative body sizes of the species. Multiple simultaneous interactions may constrain the ability of native species to trade(More)
Predation can cause morphological divergence among populations, while ontogeny and sex often determine much of morphological diversity among individuals. We used geometric morphometrics to characterize body shape in the livebearing fish Brachyrhaphis rhabdophora to test for interactions between these three major shape-determining factors. We assessed shape(More)
Natural selection often results in profound differences in body shape among populations from divergent selective environments. Predation is a well-studied driver of divergence, with predators having a strong effect on the evolution of prey body shape, especially for traits related to escape behavior. Comparative studies, both at the population level and(More)
We evaluate the cost-of-reproduction hypothesis in the burying beetle Nicrophorus orbicollis and examine how the importance of this trade-off changes as females age (i.e., the terminal-investment hypothesis). These beetles breed on small vertebrate carcasses, which serve as a food resource for them and their offspring. Consistent with the(More)
OBJECTIVE Some information is available about the parasite fauna and incidence for Clarias gariepinus in Turkey, but digenean parasites have received little attention. The purpose of the study is to contribute to the parasite fauna of Turkey. METHODS From 2007 to 2008, a total 63 Clarias gariepinus that were caught in the Asi River were purchased from the(More)
Conservation biologists rely heavily on taxonomy to set the scope for biological monitoring and recovery planning of rare or threatened species. Yet, taxonomic boundaries are seldom evaluated as falsifiable hypotheses that can be statistically tested. Here, we examine species boundaries in leatherside chub (Teleostei, Cyprinidae), an imperiled desert fish(More)
Intraspecific morphological variation in fish is typically associated with sexual dimorphism, or one of three common environmental gradients: variation in intensity of predation, variation in water velocity, or variation in feeding niche. The preponderance of examples of environment-associated morphological variation within fish species has been documented(More)
Previous studies suggested that differences in age at maturity among populations of bluegill sunfish (Lepomis macrochirus) were not genetically based, but rather were a phenotypic response to the presence of predators. I conducted two experiments to determine if the presence of largemouth bass affected age at maturity in bluegill sunfish. Bluegills from(More)