Freshwater habitats are under increasing threat due to invasions of exotic fish. These invasions typically begin with the introduction of small numbers of individuals unfamiliar with the new habitat. One way in which the invaders might overcome this disadvantage is by associating with native taxa occupying a similar ecological niche. Here we used guppies (Poecilia reticulata) from a feral popul...

We evaluated the extent to which males and females evolve along similar or different trajectories in response to the same environmental shift. Specifically, we used replicate experimental introductions in nature to consider how release from a key parasite (Gyrodactylus) generates similar or different defence evolution in male vs. female guppies (Poecilia reticulata). After 4-8 generations of ev...

Male harassment of females to gain mating opportunities is a consequence of an evolutionary conflict of interest between the sexes over reproduction and is common among sexually reproducing species. Male Trinidadian guppies Poecilia reticulata spend a large proportion of their time harassing females for copulations and their presence in female social groups has been shown to disrupt female-fema...

Under the threat of predation, animals can decrease their level of risk by moving towards other individuals to form compact groups. A significant body of theoretical work has proposed multiple movement rules, varying in complexity, which might underlie this process of aggregation. However, if and how animals use these rules to form compact groups is still not well understood, and how environmen...

It has been argued that intraspecific mate-choice copying can be adaptive under certain conditions. Dugatkin's (1992, Am. Nat.139, 1384-1389) work with guppies, Poecilia reticulataremains the most influential experimental demonstration of this phenomenon. We replicated Dugatkin's work using several choice criteria to ensure that our results were not dependent upon any single method of judging m...

Predation is thought to shape the macroscopic properties of animal groups, making moving groups more cohesive and coordinated. Precisely how predation has shaped individuals' fine-scale social interactions in natural populations, however, is unknown. Using high-resolution tracking data of shoaling fish (Poecilia reticulata) from populations differing in natural predation pressure, we show how p...

The coordinated and synchronized movement of animals in groups often referred to as collective motion emerges through the interactions between individual animals within the group. Factors which affect these interactions have the potential to shape collective movement. One such factor is familiarity, or the tendency to bias behaviour towards individuals as a result of social recognition. We exam...

Predation is the main cause of mortality during early life stages. The ability to avoid and evade potential threats is, therefore, favoured to evolve during the early stages of life. It is also during these early stages that the process of familiarization occurs. It has long been recognized that associating with familiar individuals confers antipredator benefits. Yet gaps in our knowledge remai...

The size and maturity of Trinidadian guppy (Poecilia reticulata) offspring vary among populations adapted to environments of differential predation. Guppy offspring born to low-predation, high-competition environments are larger and more mature than their high-predation ancestors. Here we ask: what specific changes in developmental or birth timing occur to produce the larger, more mature neonat...