Multiple stressors disrupt sex hormones and fitness outcomes: effects of hypoxia and turbidity on an African cichlid fish.

Freshwater organisms face a complex array of environmental stressors that can negatively affect endocrine function and subsequent fitness outcomes. Hypoxia and turbidity are two environmental stressors that are increasing due to human activities that could lead to endocrine disruption and reduced reproductive output. Our research addresses how hypoxia and elevated turbidity affect traits related to reproductive success, specifically sex hormone concentrations, investment in reproductive tissues and body size.

Intraspecific variation in crayfish behavioral traits affects leaf litter breakdown in streams.

Although intraspecific trait variation is increasingly recognized as affecting ecosystem processes, few studies have examined the ecological significance of among-population variation in behavioral traits in natural ecosystems. In freshwater habitats, crayfish are consumers that can influence ecosystem structure (e.g.

Sex, size, and prey caloric value affect diet specialization and consumption of an invasive prey by a native predator.

Escaping the control of natural enemies is thought to heavily influence the establishment success and impact of non-native species. Here, we examined how the profitability of alternative prey in combination with the presence of a competitor and predator aggressive behavior explain individual differences in diet specialization and the consumption of the invasive green porcelain crab by the native mud crab predator Results from bomb calorimetry estimates show that invasive has high caloric value relative to alternative native prey. Laboratory assays indicated that specialization and consumption of invasive was mostly exhibited by large, female , but the presence of a competitor and predator aggressiveness did not influence diet and the consumption of Thus, intrinsic factors (e.

Behavioral differences within and among populations of an African cichlid found in divergent and extreme environments.

Animals are increasingly faced with human-induced stressors that vary in space and time, thus we can expect population-level divergence in behaviors that help animals to cope with environmental change. However, empirical evidence of behavioral trait divergence across environmental extremes is lacking. We tested for variation in behavioral traits among 2 populations of an African cichlid fish ( Seegers, 1990) that experience extremes of dissolved oxygen (DO) and turbidity and are known to vary in a number of physiological and life history traits associated with these stressors.

Do native predators benefit from non-native prey?

Despite knowledge on invasive species' predatory effects, we know little of their influence as prey. Non-native prey should have a neutral to positive effect on native predators by supplementing the prey base. However, if non-native prey displace native prey, then an invader's net influence should depend on both its abundance and value relative to native prey.

Individual variation in foraging behavior reveals a trade-off between flexibility and performance of a top predator.

There is increasing evidence that behavioral flexibility is associated with the ability to adaptively respond to environmental change. Flexibility can be advantageous in some contexts such as exploiting novel resources, but it may come at a cost of accuracy or performance in ecologically relevant tasks, such as foraging. Such trade-offs may, in part, explain why individuals within a species are not equally flexible.

Reciprocal behavioral plasticity and behavioral types during predator-prey interactions.

How predators and prey interact has important consequences for population dynamics and community stability. Here we explored how predator-prey interactions are simultaneously affected by reciprocal behavioral plasticity (i.e.

Climate and pH predict the potential range of the invasive apple snail (Pomacea insularum) in the southeastern United States.

Predicting the potential range of invasive species is essential for risk assessment, monitoring, and management, and it can also inform us about a species' overall potential invasiveness. However, modeling the distribution of invasive species that have not reached their equilibrium distribution can be problematic for many predictive approaches. We apply the modeling approach of maximum entropy (MaxEnt) that is effective with incomplete, presence-only datasets to predict the distribution of the invasive island apple snail, Pomacea insularum.

Maternal exposure to predation risk decreases offspring antipredator behaviour and survival in threespined stickleback.

1. Adaptive maternal programming occurs when mothers alter their offspring's phenotype in response to environmental information such that it improves offspring fitness. When a mother's environment is predictive of the conditions her offspring are likely to encounter, such transgenerational plasticity enables offspring to be better-prepared for this particular environment.

Evolutionary game theory as a framework for studying biological invasions.

Although biological invasions pose serious threats to biodiversity, they also provide the opportunity to better understand interactions between the ecological and evolutionary processes structuring populations and communities. However, ecoevolutionary frameworks for studying species invasions are lacking. We propose using game theory and the concept of an evolutionarily stable strategy (ESS) as a conceptual framework for integrating the ecological and evolutionary dynamics of invasions.

Behavioral correlations provide a mechanism for explaining high invader densities and increased impacts on native prey.

The fact that superabundant invasive pests are also sometimes highly aggressive represents an interesting paradox. Strong intraspecific aggression should result in high intraspecific competition and limit the densities reached by exotic species. One mechanism that can allow invaders to attain high densities despite high intraspecific aggression, involves positive correlations between aggression and other behaviors such as foraging activity.