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

Predation has long been implicated as a major selective force in the evolution of several morphological and behavioral characteristics of animals. The importance of predation during evolutionary ti...

Behavioral decisions made under the risk of predation: a review and prospectus

Modern ecological research often involves the comparison of the usage of habitat types or food items to the availability of those resources to the animal. Widely used methods of determining preference from measurements of usage and availability depend critically on the array of components that the researcher, often with a degree of arbitrariness, deems available to the animal. This paper proposes a new method, based on ranks of components by usage and by availability. A virtue of the rank procedure is that it provides comparable results whether a questionable component is included or excluded from consideration. Statistical tests of significance are given for the method. The paper also offers a hierarchical ordering of selection processes. This hierarchy resolves certain inconsistencies among studies of selection and is compatible with the analytic technique offered in the paper. Central to the study of animal ecology is the usage an animal makes of its environment: specifically, the kinds of foods it consumes and the varieties of habitats it occupies. Many analytic procedures have been de- vised to treat data on the usage of such resources, particularly in relation to information on their avail- ability to the animal, for the purpose of determining "preference." The objectives of this report are to de- scribe the problem of determining preference by com- paring usage and availability data, to illustrate a seri- ous shortcoming in the routine application of most procedures for comparing these data, and to suggest a new method that resolves this difficulty. The pro- posed technique results in a ranking of the components on the basis of preference, and permits significance tests of the ranking.

/pdf/the-comparison-of-usage-and-availability-measurements-for-4iriiv715a.pdf

The comparison of usage and availability measurements for evaluating resource preference

Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patches; and (4) optimal patterns and speed of movements. In this review we discuss each of these categories separately, dealing with both the theoretical developments and the data that permit tests of the predictions. The review is selective in the sense that we emphasize studies that either develop testable predictions or that attempt to test predictions in a precise quantitative manner. We also discuss what we see to be some of the future developments in the area of optimal foraging theory and how this theory can be related to other areas of biology. Our general conclusion is that the simple models so far formulated are supported are supported reasonably well by available data and that we are optimistic about the value both now and in the future of optimal foraging theory. We argue, however, that these simple models will requre much modification, espicially to deal with situations that either cannot easily be put into one or another of the above four categories or entail currencies more complicated that just energy.

Citation classic - optimal foraging - a selective review of theory and tests

Although the potential genetic risks associated with rare or endangered plants and small populations have been discussed previously, the practical role of population genetics in plant conservation remains unclear. Using theory and the available data, we examine the effects of genetic drift, inbreeding, and gene flow on genetic diversity and fitness in rare plants and small populations. We identify those circumstances that are likely to put these plant species and populations at genetic risk. Warning signs that populations may be vulnerable include changes in factors such as population size, degree of isolation, and fitness. When possible, we suggest potential management strategies.

/pdf/population-genetic-consequences-of-small-population-size-3onkvtfxng.pdf

POPULATION GENETIC CONSEQUENCES OF SMALL POPULATION SIZE: Implications for Plant Conservation

Beginning with Emlen (1966) and MacArthur and Pianka (1966) and extending through the last ten years, several authors have sought to predict the foraging behavior of animals by means of mathematical models. These models are very similar,in that they all assume that the fitness of a foraging animal is a function of the efficiency of foraging measured in terms of some "currency" (Schoener, 1971) -usually energy- and that natural selection has resulted in animals that forage so as to maximize this fitness. As a result of these similarities, the models have become known as "optimal foraging models"; and the theory that embodies them, "optimal foraging theory." The situations to which optimal foraging theory has been applied, with the exception of a few recent studies, can be divided into the following four categories: (1) choice by an animal of which food types to eat (i.e., optimal diet); (2) choice of which patch type to feed in (i.e., optimal patch choice); (3) optimal allocation of time to different patch...

/pdf/optimal-foraging-a-selective-review-of-theory-and-tests-3ar3ls90ph.pdf

Optimal foraging: A selective review of theory and tests

Proponents of optimal foraging theory attempt to predict the behavior of animals while they are foraging; this theory is based on a number of assump­ tions ( 133 , 155 , 2 10, 23 1 ) . First, an individual's contribution to the next generation (i.e. its "fitness") depends on its behavior while foraging. This contribution may be measured genetically or culturally as the proportion of an individual's genes or "ideas", respectively, in the next generation. In the former case, the theory is simply an extension of Darwin's theory of evolution. Second, it is assumed that there should be a heritable component of foraging behavior, i.e. an animal that forages in a particular manner should be likely to have offspring that tend to forage in the same manner. This heritable compo­ nent can be either the actual foraging responses made by an animal or the rules by which an animal learns to make such responses. In other words, optimal foraging theory may apply regardless of whether the foraging behavior is learned or innate. Given these first two assumptions, it follows that the proportion of individuals in a population foraging in ways that enhance their fitness will tend to increase over time. Unless countervailed by sufficiently strong group selection (see 287, 242), foraging behavior will therefore evolve, and the average foraging behavior will increasingly come to be characterized by those characteristics that enhance individual fitness. The third assumption is that the relationship between foraging behavior and fitness is known. This relationship is usually referred to as the currency of fitness (23 1 ) . In general, any such currency will include a time scale, although in some cases it may be assumed that fitness is a function of some rate.

Optimal Foraging Theory: A Critical Review

Optimal foraging: movement patterns of bumblebees between inflorescences.

Eastern and Western Gambusia (i.e., Gambusia holbrooki and G. affinis, respectively) are considered together here because these two fish species are very closely related, similar in appearance, similar in biology and often confused. Widely divergent attitudes have developed with regard to these fish with some viewing them as being highly beneficial to humans through controlling mosquitoes and the diseases they harbor, and others expressing concern about the negative impacts that these fish may have on other species with which they interact. Because of the widespread distribution, high levels of abundance, ease of capture and captive maintenance, and divergent attitudes, a very large and diffuse literature has developed with regard to these species. In fact, few fish species have been studied as much as or more than these two species combined. There has, however, been no comprehensive review of their biology published to date. As it is not possible to provide a comprehensive review of Gambusia biology in one reasonably sized document, I provide here a review of aspects of their biology at the level of species and individual. In another review I focused instead on the levels of population and species communities and consider the impacts that these fish have on mosquitoes and other organisms (Pyke, unpublished). As would be expected of such widespread and abundant species, Gambusia affinis and G. holbrooki are clearly very tolerant, adaptable and variable in their biology, at both an individual and population level. Both individuals and populations can tolerate, and often thrive within, a wide range of conditions and the abilities of individuals to do this are enhanced if they have time to acclimate to any changes. Populations can adapt through genetic or evolutionary changes in response to conditions that vary in space or time, and there is significant genetic variation within and between populations.

http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0019/409600/Reviews-in-fish-biology-and-fisheries-2005.pdf

Graham H. Pyke

Papers

Optimal foraging: A selective review of theory and tests

Citation classic - optimal foraging - a selective review of theory and tests

Optimal Foraging Theory: A Critical Review

Optimal foraging: movement patterns of bumblebees between inflorescences.

A review of the biology of Gambusia affinis and G. holbrooki.