The Trinidadian guppy (Poecilia reticulata) is well known to biologists and home aquarium enthusiasts alike. Scientists have studied guppies for most of the twentieth century. Some of the most intensive recent research has been conducted by behavioral ecologists, who have found that the guppy mating system makes guppies especially useful in the study of sexual selection and mate choice. By observing guppy behavior in aquaria, researchers hope to obtain new insights into how selection operates in natural populations. Here Anne Houde summarizes and synthesizes the scientific work done to date, relates the empirical findings on guppies to current themes in sexual selection theory, and suggests new directions for future research. This book describes the sexual behavior of guppies and examines how mate choice by females leads to the evolution of the conspicuous colors and the courtship displays for which guppies are widely recognized. The author shows that female guppies prefer males with bright color patterns, especially those with orange spots, and that the mating preferences of females lead to sexual selection on both color patterns and courtship displays of males. Houde's work addresses a number of areas that are of interest in sexual selection, including the remarkable degree of plasticity and evolutionary lability of sexual behavior in guppies, geographic variation in mating preferences, possible mechanisms for the evolution of female mating preferences, and the role of sexual selection in speciation. In conclusion, the author explores the implications of her findings for behavioral ecologists who study sexual selection in other species.

This thesis examines the use of two social behaviors in Poecilia reticulata. In my first study, I observed the effect of female sexual responsiveness on the use of mate-choice copying. When shown two males, each paired with a model female, females found a previously unattractive male more attractive after viewing him with a sexually responsive female. This finding presents a new important social factor to sexual selection. In my second study, I observed aggression around a limited food source. I first manipulated the distribution of female size within a group. In a second experiment, I altered the spatial distribution of the food. Female size distribution was found to have a limited effect in aggression rates. Contrary to previous studies, my results showed no effect of spatial distribution of food on aggression. Further research needs to be performed to accurately determine the factors influencing the use of aggressive behavior in guppies.

The Ruff is a fascinating species whose elaborate breeding behaviour has captivated ornithologists for decades. Their communal display grounds, or leks, provide an extreme example of a social system widespread in birds and other animals, in which brilliantly plumaged males seemingly compete for the attention of passing females. In this book, Johan van Rhijn explores this complex and intricate drama, both to lay bare the details of the players' private lives, and to provide a means of exploring the wider variety of wader breeding systems. Strands of evidence for all aspects of the Ruffs life, in and out of the breeding season, come together to give a thought-provoking insight into this important area of biology. Specialists and birdwatchers alike will have much to learn from this intriguing story and the insights it provides. Illustrated by Ian Willis.