Effects of reliance on stored sperm on reproduction in the sailfin molly Poecilia latipinna.

The impacts of relying on stored sperm were evaluated in the sailfin molly, Poecilia latipinna. Females reliant on stored sperm had fewer offspring compared to remated females, but offspring size and short-term growth rate did not differ. Thus, females may use stored sperm in cases such as previous mating with a preferred male, lack of access to mating opportunities during a reproductive cycle, or to maximize egg fertilization. Females do not compensate for producing fewer offspring however, by allocating more resources to offspring relative to their size or initial growth.

Assays to Detect UV-reflecting Structures and Determine their Importance in Mate Preference using the Sailfin Molly Poecilia latipinna.

Many organisms use cues and signals beyond human sensitivity during social interactions. It is important to take into account how organisms perceive their worlds when trying to understand their behavior and ecology. Sensitivity to the ultraviolet spectrum (UV; 300 - 400 nm) is found across multiple genera of birds, fish, reptiles, amphibians, and even mammals. This protocol describes a technique for examining organisms for the presence of UV-reflecting structures and a method for testing whether these cues are used as social signals in the context of mate choice. A spectrophotometer is used to detect the presence of UV reflectance and variation in reflective intensity between individuals and sexes. An example of this technique is presented in which a dichotomous mate choice test exposes sexually receptive individuals to opposite sex individuals whose visual appearance can be manipulated by filters that either transmit full spectrum or block UV wavelengths. This system allowed for the determination that female, but not male, sailfin mollies (Poecilia latipinna) were using UV markings as part of their mating decisions. These types of studies serve to expand our knowledge of the range of organisms that utilize UV and provide insight into how UV plays a role in their lives.

Tailored Enrichment Strategies and Stereotypic Behavior in Captive Individually Housed Macaques (Macaca spp.).

The welfare of nonhuman animals in captivity is widely dependent on the natural psychological, physical, and behavioral needs of the animals and how adequately these needs are met. Inability to engage in natural behaviors can lead to chronic stress and expression of stereotypic behavior. The majority of research on decreasing stereotypic behavior in captivity addresses problems at the group level and does not account for individual variability in each animal's needs, history, and preferences. This study combined physiological and behavioral measures of well being to comprehensively assess the unique needs of individually housed captive macaques (Macaca spp.) with the aim of developing tailored welfare strategies. Behavioral and hormonal data were collected under 2 conditions: baseline and individualized enrichment. The results showed a significant decrease in stereotypic behavior under the enrichment condition. Additionally, 7 out of 9 individuals showed a decrease in fecal glucocorticoid (stress hormone) levels, indicating a reduction in hypothalamic-pituitary-adrenal activity. Addressing welfare on an individual, rather than group, level allows for a better overall characterization of well being and maximizes the probability of improving the welfare of each animal.

Brain transcriptomic response of threespine sticklebacks to cues of a predator.

Predation pressure represents a strong selective force that influences the development and evolution of living organisms. An increasing number of studies have shown that both environmental and social factors, including exposure to predators, substantially shape the structure and function of the brain. However, our knowledge about the molecular mechanisms underlying the response of the brain to environmental stimuli is limited. In this study, we used whole-genome comparative oligonucleotide microarrays to investigate the brain transcriptomic response to cues of a predator in the threespine stickleback, Gasterosteus aculeatus. We found that repeated exposure to olfactory, visual and tactile cues of a predator (rainbow trout, Oncorrhynchus mykiss) for 6 days resulted in subtle but significant transcriptomic changes in the brain of sticklebacks. Gene functional analysis and gene ontology enrichment revealed that the majority of the transcripts differentially expressed between the fish exposed to cues of a predator and the control group were related to antigen processing and presentation involving the major histocompatibility complex, transmission of synaptic signals, brain metabolic processes, gene regulation and visual perception. The top four identified pathways were synaptic long-term depression, RAN signaling, relaxin signaling and phototransduction. Our study demonstrates that exposure of sticklebacks to cues of a predator results in the activation of a wide range of biological and molecular processes and lays the foundation for future investigations on the molecular factors that modulate the function and evolution of the brain in response to stressors.

The repeatability of behaviour: a meta-analysis.

There is increasing interest in individual differences in animal behaviour. Recent research now suggests that an individual's behaviour, once considered to be plastic, may be more predictable than previously thought. Here, we take advantage of the large number of studies that have estimated the repeatability of various behaviours to evaluate whether there is good evidence for consistent individual differences in behaviour and to answer some outstanding questions about possible factors that can influence repeatability. Specifically, we use meta-analysis to ask whether different types of behaviours were more repeatable than others, and if repeatability estimates depended on taxa, sex, age, field versus laboratory, the number of measures and the interval between measures. Some of the overall patterns that were revealed by this analysis were that repeatability estimates were higher in the field compared to the laboratory and repeatability was higher when the interval between observations was short. Mate preference behaviour was one of the best studied but least repeatable behaviours. Our findings prompt new insights into the relative flexibility of different types of behaviour and offer suggestions for the design and analysis of future research.