Ethology

Defensive mutualism is a component of trophic cascades, and stressors that affect cooperative and aggressive behaviors can influence defensive services. We exposed stressed and non-stressed aphid-tending thatch ants to an aphid predator stimulus (e.g., lady beetle) approximately 5 and 13 weeks after the simulated bear attack. Our results suggest that predation stress may cause changes in ant aggressive defense behavior later in the growing season, and these effects may be complicated by yearly differences in abiotic and biotic factors.

Rock cavy alarm calls are finely modulated by threat proximity.

Photo of a female chimpanzee (Ikuru) at Ngamba Island Chimpanzee Sanctuary, Uganda (photo by Sofia Forss). The Ape Research Index (ARI) project aims to measure the diversity of cognitive research efforts carried out on captive chimpanzees worldwide. In this article we demonstrate that a facility bias exists in where research has been conducted on captive chimpanzees. Both between and within facilities, we identified important variation in the level and type of research exposure of individual chimpanzees.

The intensity of competition and size asymmetry between males influences color expression in the cichlid Astatotilapia burtoni. When space between territories was large, more males adopted the yellow phenotype relative to the blue phenotype over time. Body size differences between males influenced color expression but this effect dependent on territory distance treatment.