Developmental Social Experience Changes Behavior in a Threatening Environment in Catfish.

Coordinated responses to threats are important for predator evasion in many species. This study examines the effect of developmental social experience on antipredator behavior and group cohesion in a highly gregarious catfish that communicates via tactile interaction, We reared fish either in a mixed-age group of age-matched peers and adult (mixed-age condition, or MAC), or with age-matched peers only (same-age condition, or SAC). A startle test was conducted with small groups of subadults from either social rearing condition.

Comprehensive Husbandry Protocol for Catfish and Many Other Amazonian Species.

A variety of fish species have proven instrumental in the investigation of evolution, behavior, ecology, and physiology, among many other fields. Many model systems (e.g.

Philopatry yields higher fitness than dispersal in a cooperative breeder with sex-specific life history trajectories.

Social evolution is tightly linked to dispersal decisions, but the ecological and social factors selecting for philopatry or dispersal often remain obscure. Elucidating selection mechanisms underlying alternative life histories requires measurement of fitness effects in the wild. We report on a long-term field study of 496 individually marked cooperatively breeding fish, showing that philopatry is beneficial as it increases breeding tenure and lifetime reproductive success in both sexes.

Stability of Drugs Stored in Helicopters for Use by Emergency Medical Services: A Prospective Observational Study.

Study Objective: Drugs stored in rescue helicopters may be subject to extreme environmental conditions. The aim of this study was to measure whether drugs stored under the real-life conditions of a Swiss helicopter emergency medical service (HEMS) would retain their potency over the course of 1 year.

Methods: A prospective, longitudinal study measuring the temperature exposure and concentration of drugs stored on 2 rescue helicopters in Switzerland over 1 year.

The costs and benefits of larger brains in fishes.

The astonishing diversity of brain sizes observed across the animal kingdom is typically explained in the context of trade-offs: the benefits of a larger brain, such as enhanced cognitive ability, are balanced against potential costs, such as increased energetic demands. Several hypotheses have been formulated in this framework, placing different emphasis on ecological, behavioural, or physiological aspects of trade-offs in brain size evolution. Within this body of work, there exists considerable taxonomic bias towards studies of birds and mammals, leaving some uncertainty about the generality of the respective arguments.

Multiple Evolutionary Routes to Monogamy: Modeling the Coevolution of Mating Decisions and Parental Investment.

The relationships between mating decisions and parental investment are central to evolution, but to date few theoretical treatments of their coevolution have been developed. Here we adopt a demographically explicit, adaptive dynamics approach to analyze the coevolution of female mating decisions and parental investment of both sexes in a self-consistent way. Our models predict that where females cannot interfere with one another's mating decisions and where they do not differ in their survival and fecundity prospects, monogamy should be rare, favored only under harsh environmental conditions, in sparse populations.

Predation risk drives social complexity in cooperative breeders.

Predation risk is a major ecological factor selecting for group living. It is largely ignored, however, as an evolutionary driver of social complexity and cooperative breeding, which is attributed mainly to a combination of habitat saturation and enhanced relatedness levels. Social cichlids neither suffer from habitat saturation, nor are their groups composed primarily of relatives.

First- and second-order sociality determine survival and reproduction in cooperative cichlids.

Cooperative breeders serve as a model to study the evolution of cooperation, where costs and benefits of helping are typically scrutinized at the level of group membership. However, cooperation is often observed in multi-level social organizations involving interactions among individuals at various levels. Here, we argue that a full understanding of the adaptive value of cooperation and the evolution of complex social organization requires identifying the effect of different levels of social organization on direct and indirect fitness components.