Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

We review the observations and the basic laws describing the essential aspects of collective motion -- being one of the most common and spectacular manifestation of coordinated behavior Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities As such, these models allow the establishing of a few fundamental principles of flocking In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences

Collective Motion

Publisher Summary This chapter reviews the present empirical and theoretical work on antipredator decision making. The ways in which predators influence the behavioral decisions made by their prey is now the subject of a large and growing literature. Some notable recent advances include clear demonstrations that antipredatory decision making (1) may influence many aspects of reproductive behavior, (2) has demonstrable long-term consequences for individual fitness, and (3) may influence the nature of ecological systems themselves. There have also been many advances in the theory of antipredator behavior, which should provide a sound conceptual basis for further progress. Attention is needed for further work on the effects that predator and prey have on the other's behavioral decisions. The range of reproductive behaviors influenced by the risk of predation also requires much more investigation. Work on the long-term costs of antipredator decision making needs more empirical documentation and greater taxonomic diversity. Work on the ecological implications of antipredatory decision making has only scratched the surface, especially with regard to population-level effects and species interactions. Theoretical investigations should also play a prominent role in future work.

Stress and Decision Making under the Risk of Predation: Recent Developments from Behavioral, Reproductive, and Ecological Perspectives

One of the most striking patterns in biology is the formation of animal aggregations. Classically, aggregation has been viewed as an evolutionarily advantageous state, in which members derive the benefits of protection, mate choice, and centralized information, balanced by the costs of limiting resources. Consisting of individual members, aggregations nevertheless function as an integrated whole, displaying a complex set of behaviors not possible at the level of the individual organism. Complexity theory indicates that large populations of units can self-organize into aggregations that generate pattern, store information, and engage in collective decision-making. This begs the question, are all emergent properties of animal aggregations functional or are some simply pattern? Solutions to this dilemma will necessitate a closer marriage of theoretical and modeling studies linked to empirical work addressing the choices, and trajectories, of individuals constrained by membership in the group.

https://science.sciencemag.org/content/sci/284/5411/99.full.pdf

Complexity, pattern, and evolutionary trade-offs in animal aggregation.

/pdf/an-introduction-to-the-aquatic-insects-of-north-america-20i7stzjkw.pdf

An Introduction to the Aquatic Insects of North America

Individual differences make a difference in the trajectories of simulated schools of fish

Animal groups are highly variable in their spatial structure, and individual fitness is strongly associated with the spatial position of an animal within a group. Predation risk and food gains are often higher at the group peripheries; thus, animals must trade-off predation costs and foraging benefits when choosing a position. Assuming this is the case, we first use simulation models to demonstrate how predation risk and food gains differ for different positions within a group. Second, we use the patterns from the simulation to develop a novel model of the trade-off between the costs and the benefits of occupying different positions and predict the optimal location for an animal in a group. A variety of testable patterns emerge. As expected, increasing levels of satiation and vulnerability to predators and increasing predation risk result in increased preferences for central positions, likely to lead to increased competition or more tightly packed groups. As food availability increases, individuals should first prefer center positions, then edge, and returning to central positions under highest food levels. Increasing group size and/or density lead to more uniform preferences across individuals. Finally, we predict some situations where individuals differing in satiation and vulnerability prefer a range of different locations and other situations where there is an abrupt dichotomy between central and edge positions, dependent on the levels of monopolization of food by peripheral individuals. We discuss the implications of our findings for the structure of groups and the levels of competition within them and make suggestions for empirical tests.

Optimal individual positions within animal groups

The benefits and costs of group living are likely to be asymmetric within a group. Animals at the edge of a group are more at risk from predators, according to the selfish herd hypothesis, but are also more likely to obtain scattered food resources. Does an animal's choice between these two conflicting positions depend on its body reserves? The hunger level of marked whirligig beetles (Coleoptera: Gyrinidae) was manipulated and the positions of individuals relative to the rest of the group on the surface of the water were determined with image analysis software. In 12 out of 13 groups, of approximately 18 beetles each, hungry beetles were closer to the edge of a group and had a higher distance to their nearest neighbor than well-fed beetles. Hungry beetles at the edge obtained nearly all of the food particles dropped onto the surface of the water. These results show that position preferences within groups may involve a dynamic feedback between foraging, predator avoidance, and shortterm hunger levels.

Position preferences within groups : do whirligigs select positions which balance feeding opportunities with predator avoidance ?

Although there is a worldwide concern about anthropogenic causes of pollinator declines, little is known about how specific land use practices, such as agriculture, urbanization, and logging, influence the diversity and abundance of native bees. We investigated the impact of logging on native bees (Apoidea) in the Adirondack Mountains of New York State (USA) in an area isolated from the effects of both agriculture and introduced honey bees. Specifically, we measured midsummer bee abundance and diversity on matched 5-acre plots two and three years after experimental logging cuts to remove 30, 60, and 100% of the trees. We obtained additional data on floral abundance and weather in relation to bee abundance. We found that bee abundance and diversity was highest in areas where the most trees had been removed. Also, we found little difference in diversity between the two study years, despite major differences in weather. The observed diversity patterns were best explained by the observed increase in ...

Impacts of Logging on Midsummer Diversity of Native Bees (Apoidea) in a Northern Hardwood Forest

To explain the evolution of grouping, Hamilton's selfish herd theory assumes that predators attack the nearest prey and that both are acting on a 2-dimensional (2-D) plane. This proximity assumption in his theory is one explanation for marginal predation, the phenomenon whereby predators attack peripheral members of a prey group. However, in some ecological circumstances, predators move in 3-dimensional (3-D) space and prey in 2 dimensions. Because a predator coming from above or below the group may have relatively equal access to all members, marginal predation cannot be assumed. In this paper, we test whether marginal predation occurs in such a 3-D/2-D geometry. We carried out 3 controlled laboratory experiments in which fish attack prey grouped at the water's surface. Predators were bass (Micropterous salmoides) or goldfish (Carassius auratus), and prey groups were either free-swimming whirligig beetles (Dineutes discolor) or a constrained group of tadpoles (Bufo bufo). In all 3 experiments, predators were significantly more likely to attack the periphery of prey groups. Our experiments also show that marginal predation is robust to differences in overall density within a prey group and that the fish are not reacting to observable state or behavioral correlates to position within a prey group. Furthermore, our results showed that predators will attack group margins even when there is no variation, due to position, in nearest neighbor distance.

/pdf/do-3-d-predators-attack-the-margins-of-2-d-selfish-herds-2adq70310a.pdf

William L. Romey

Papers

Individual differences make a difference in the trajectories of simulated schools of fish

Optimal individual positions within animal groups

Position preferences within groups : do whirligigs select positions which balance feeding opportunities with predator avoidance ?

Impacts of Logging on Midsummer Diversity of Native Bees (Apoidea) in a Northern Hardwood Forest

Do 3-D predators attack the margins of 2-D selfish herds?