Humans, being visually oriented, are well versed in camouflage and how animals hide from predators that use vision to locate prey. However, many predators do not hunt by sight; they hunt by scent. This raises the question: do survival mechanisms and behaviors exist which allow animals to hide from these olfactory predators? If so, what are they, and how do they work? Predator-Prey Dynamics: The Role of Olfaction examines environmental as well as biological and behavioral elements of both predators and prey to answer gaps in our current knowledge of the survival dynamics of species. Beginning with a thorough look at the mechanics of olfaction, the author explains how predators detect, locate, and track their prey using odor trails on the ground or odor plumes in the air. Understanding the physics of airflow is the next step to understanding the potential for manipulating and masking scent. While a bush may conceal an animal visually from a predator, it will not protect an animal from a predator using olfaction. To hide from the latter, an animal needs to hide in locations where turbulence and updrafts will disperse its scent. The book addresses tradeoffs that animals must make given their dual needs to hide from predators and to procure food and water. Studies of mammalian and avian behavior provide examples on the actual use and efficacy of olfactory camouflage tactics. The book concludes with a redefinition of ecological terms based on the physics of airflow and a summary of the theory and implications of olfactory predator--prey dynamics. Introducing the mechanics of olfaction and its influence on the behavior of both predators and prey, Predator-Prey Dynamics: The Role of Olfaction presents a new perception of the world and enables us to understand and more effectively manage the delicate survival dynamics of animals in the wild.
In this study of arthropod predador-prey systems Michael Hassell shows how many of the components of predation may be simply modeled in order to reveal their effects on the overall dynamics of the interacting populations. Arthropods, particularly insects, make ideal subjects for such a study because their generation times are characteristically short and many have relatively discrete generations, inviting the use of difference equation models to describe population changes. Using analytical models framed in difference equations, Dr. Hassell is able to show how the detailed biological processes of insect predator-prey (including host-parasitoid) interactions may be understood. Emphasizing the development and subsequent stability analysis of general models, the author considers in detail several crucial components of predator-prey models: the prey's rate of increase as a function of density, non-random search, mutual interference, and the predator's rate of increase as a function of predator survival and fecundity. Drawing on the correspondence between the models and field and laboratory data, Dr. Hassell then discusses the practical implications for biological pest control and suggests how such models may help to formulate a theoretical basis for biological control practices.
Prey interact not only with their predators, but also conspecifics, and must balance the conflicting need of gathering resources and avoiding predation. In this study, I examine the effect of spatial dynamics, predation, and intraspecific competition on predator-prey population dynamics using ordinary, partial, and integro-differential equation models. Specifically, the Rosenzweig-MacArthur predator-prey model is modified to examine the effect that differences between the two species' spatial distributions have on coexistence of predators and prey and the short-term effects of predation on prey aggregations.
"Herbivorous prey are known to employ various strategies to avoid predation. In this thesis, I investigated interactions of eriophyid mites, important agricultural pests, which hide inside refuges, where they are temporarily safe, and their natural enemies. I found that only a smaller member of the predatory mite guild on coconut trees was able to enter refuges of the coconut mite, consisting of the area of the coconut covered by the perianths. However, they could only do so after the distance between the perianth and the coconut surface had increased with time. To further understand the role of this refuge, I experimentally increased its entrances in the field, and found that successful control of the pest critically hinged on refuge opening and predator size. I furthermore prove that this predatory mite and a larger, commercially available species responded to prey-associated volatiles, but only the smallest mite was able to move into narrow spaces such as the prey refuge. Although it has been suggested that larger predators have the advantage to easily subdue their prey, being small thus seems advantageous when prey hide inside refuges. I furthermore demonstrate that this small predator can control the dry bulb mite on Dutch tulip bulbs. These mites hide between bulb scales and cannot be reached by the conventionally used larger predatory mites. Thus, I show that a small tropical predatory mite from the tropics can be used to control an important pest of Dutch tulip bulbs."--Samenvatting auteur.
This book addresses the fundamental issues of predator-prey interactions, with an emphasis on predation among arthropods, which have been better studied, and for which the database is more extensive than for the large and rare vertebrate predators. The book should appeal to ecologists interested in the broad issue of predation effects on communities.
Eulerian models based on integro-differential equations may be used to model collective behaviour, by treating the group of individuals as a population density. In comparison with Lagrangian models, where one tracks distinct individuals, Eulerian models are formulated as evolution equations for the density field, and hence permit rigorous analysis to be performed. The population densities are influenced by the social interactions of attraction, repulsion and alignment. We introduce a new model for predator-prey dynamics that generalizes a previous integro-differential equation model by introducing the predator dynamics and a blind zone for the prey. Extensive simulations were performed to showcase the realism of the model, and these simulations are presented in four stages. First, the prey reacts solely due to interactions with itself. Second, a stationary predator distribution is introduced. Third, the predator's distribution remains fixed but moves in a predetermined fashion. Finally, the predator dynamics are governed by equations analogous to those of the prey. Variations in the size of the blind zone for the prey are explored that can determine whether a prey cluster stays together or splits apart. The prey and predator demonstrate realistic behaviours that are seen in nature.