Stress hormones and mate choice

A few recent studies have suggested that glucocorticoid stress hormones can play a role in sexual selection. In terms of mate choice, these studies have shown that individuals can exhibit preferences for mates with either low baseline or peak glucocorticoid levels. This appears to occur because stress hormones can be key mediators of many condition-dependent, […]

Integrating stress physiology, environmental change, and behavior in free-living sparrows

As weather deteriorates, breeding animals have a diverse array of options to ensure survival. Because of their mobility, birds can easily abandon territories to seek out benign conditions away from the breeding site. The timing of abandonment, however, may have repercussions for territory size, mate quality, reproductive success, and survival. There is a large body […]

Evaluation of an alternative to feeding whole frozen fish in belugas (Delphinapterus leucas)

Abstract Feeding fish to captive piscivores can be challenging owing to cost, availability, variability in nutrient, and caloric composition, as well as handling and storage concerns. This trial evaluated the response of three belugas to being fed Fish Analog, an alternative to frozen fish. Body condition, gut transit time, serum chemistry and metabolic hormone analytes, […]

Non-lethal effects of predators on body growth and health state of juvenile lizards, Psammdromus algirus

Predation risk does not necessarily increase predation rates because prey may be able to behave differentially to cope with higher predation risk. However, antipredatory behaviors may be costly, leading to negative, although non-lethal, effects of predators on prey. We examined in outdoor enclosures whether an experimental increase in predation pressure, which did not increase direct […]

Behavioural type, status and social context affect behaviour and resource allocation in cooperatively breeding cichlids

Individuals often show consistent differences in behavioural traits that may belong to a behavioural syndrome. Aggressive propensity is usually an important component of consistent behavioural types, potentially generating benefits in resource competition with conspecifics that may be traded off against costs in other contexts (e.g. acquisition of mates or coexistence with group members). Such trade-offs […]

Stress responsiveness, age and body condition interactively affect flight initiation distance in breeding female eiders

Predation may drive differential selection among personality types, but the mechanism linking personality with predation risk is poorly understood. One such mechanism may be provided by stress hormones (corticosterone in birds), which are linked to boldness towards predators. However, because of feedbacks between boldness and future fitness expectations, the relationship between boldness and stress physiology […]

Assessing translocation outcome: Comparing behavioral and physiological aspects of translocated and resident African elephants (Loxodonta africana)

Evaluating translocation outcomes is important for improving wildlife management and conservation actions. Often, when quick decisions need to be made and long-lived animals with slow reproduction rates are translocated, traditional assessment methods such as long-term survival and reproductive success cannot be used for assessingtranslocation outcomes. Thus, alternative, seldom used, measures such as comparing the behavior […]

The direct costs of living in a sexually harassing environment

Sexual conflict can lead to individuals evolving behaviours to circumvent preferences of the opposite sex. For example, females have been shown to adjust their behaviours depending on the risk of sexual harassment. In the present study we investigated the effects of sexual harassment in sailfin mollies, Poecilia latipinna, on both females and males depending on […]

Maternal behaviour in beef cows is individually consistent and sensitive to cow body condition, calf sex and weight

Beef cows’ maternal care is essential for calf survival and fitness. In this study, we assessed the consistency of maternal care within and between lactations and investigated whether maternal care increases with mother’s parity and body condition and whether mothers care more intensely for males and for calves with lower body weight. The Trivers–Willard hypothesis […]

The influence of siblings on body condition in a social spider: is prey sharing cooperation or competition?

Siblings living together compete with each other for resources, yet they may also cooperate to maximize their inclusive fitness. In social spiders, siblings share prey and may both compete and cooperate to obtain this resource. In the laboratory, the social huntsman spider, Delena cancerides, readily shares prey captured by other colony members; however, these spiders […]