Predator-Prey Dynamics: The Role of Olfaction

Olfactory Predators and Odorants Olfactory organs of vertebrates Comparing the olfactory ability of humans to other mammals Use of olfaction by birds to locate food Which modality is most important to snakes in locating prey? Which modality is most important to predatory mammals in locating prey? Characteristics of odorants Perception of odor mixtures Sources of odorants from mammals and birds Using odors to detect differences between species or individuals Can animals hide from olfactory predators by changing their odor? Can animals hide from olfactory predators by masking their odor with another, overpowering one? Factors influencing the evaporation rate of odorants Movement of odorants through the atmosphere The olfactory concealment theory Detecting and Locating Prey Through Depositional Odor Trails Creation of depositional odor trails Determining how long ago a trail was created Determining the direction of an odor trail Impact of environmental conditions on depositional odor trails How good are predators at following a depositional odor trail? Behavioral tactics used by deer and hares to escape from tracking dogs Locating home ranges using olfactory cues What prey can do to minimize their risk from depositional odor trails What olfactory predators can do to maximize the usefulness of depositional odor trails Using Airborne Odorants to Detect the Presence of Prey The challenge of using airborne odorants to detect the presence of prey Impact of a steady wind on a predator's ability to detect an odor plume How far can predators detect prey by sensing the quarry through its odor plume? Can prey reduce their odorant emission rate? Impact of wind velocity on odorant concentration Impact of turbulence on odorant concentration Differences in time-averaged and instantaneous views of odor plumes Impact of lateral and vertical turbulence on the size of instantaneous odor plumes Measurements of turbulence Spatial and temporal structure of odor plumes Effect of atmospheric instability on the vertical dispersion of odorants Diurnal changes in atmospheric stability Impact of atmospheric instability on olfactory predators and their prey Using Odor Plumes to Locate Prey and the Impact of Convection Locating prey through airborne odorants Potential methods animals can use to locate an odor source How moths locate sources of odor plumes How tsetse flies use odor plumes to find their hosts Do predators develop olfactory search images of their prey? Impact of wind velocity on the ability of predators to locate prey using odor plumes Impact of wind velocity of olfactory predators and their prey Effect of variable wind speed and direction on use of odor plumes to locate prey Convective turbulence caused by local topography Impact of local convective currents on olfactory predators and their prey Experimental Evidence that Updrafts and Turbulence Hinder the Ability of Predators to Find Prey Using Olfaction Experiment 1: do updrafts and atmospheric turbulence hinder the ability of dogs to find birds? Experiment 2: are nest predation rates by free-ranging predators lower in areas where updrafts occur? Experiment 3: do updrafts and turbulence hinder the ability of free-ranging predators to find artificial nests? Turbulence Caused by Isolated Surface Features Mechanical turbulence caused by isolated surface features Impact of turbulence caused by isolated surface features on olfactory predators and their prey Mechanical turbulence caused by an isolated plant Impact of turbulence caused by isolated trees on olfactory predators and their prey Turbulence caused by shelterbelts Impact of turbulence across shelterbelts on olfactory predators and their prey Turbulence Over Rough Surfaces Aerodynamic roughness length Impact of z on olfactory predators and their prey Zero-plane displacement Airflow across habitat edges Airflow from a Smooth to a Rough Surface Airflow from Rough to Smooth Surfaces Impact of turbulence caused by habitat edges on olfactory predators and their prey Turbulence Within and Below Plant Canopies Convective turbulence within plant canopies Mechanical turbulence within plant canopies Airflow and turbulence within forb and grass canopies Movement of a pheromone plume within a grain field Airflow within the subcanopy of forests Differences in the movement of odor plumes above grass canopies and within forest canopies How does turbulence within a forest plantation differ from a naturally reproducing or old-growth forest? Impact of turbulence within a forest subcanopy on olfactory predators and their prey Airflow in savannas Impact of turbulence in forests, prairies, and savannas on olfactory predators and their prey Trade-Offs Required to Achieve Optimal Hiding Strategies Optimal hiding strategies for prey Optimal foraging strategies for predators How predators develop search images of prey How birds learn where to nest Interplay between a predator's optimal foraging strategy and a prey's optimal hiding strategy Trade-offs involving avoiding detection versus capture Trade-offs required to avoid both visual and olfactory predators Trade-offs between the need to avoid olfactory predators and to meet the other necessities of life Trade-offs between the need to reproduce this year versus during future years Trade-offs involving the timing of dangerous activities Trade-offs among injuries, illness, starvation, and predators Summary Impact of Olfactory Predators on the Behavior of Female Ungulates During Parturition and on the Behavior of Their Young Do females reduce their production of odorants at parturition sites or the bedding sites of their young? Is the behavior of neonates designed to hinder the ability of predators to find them using olfaction? Do fawns adjust the timing of their movements to avoid attracting the attention of visual or olfactory predators? Do female ungulates select parturition sites, and do young select bedding grounds where olfactory predators would have a hard time finding them? Do Nest Site Characteristics Influence Nest Predation Rates by Olfactory Predators? Impact of avian mass, surface area, and metabolic rates on olfactory predators Impact of nest characteristics on olfactory predators Do Weather, Convection, Isolated Surface Features, or Shelterbelts Influence Nest Predation Rates of Olfactory Predators? Impact of weather on olfactory predators Impact of convection on olfactory predators Impact of isolated surface features on olfactory predators Impact of shelterbelts on olfactory predators Do Prairies, Savannas, Forests, or Edge Habitats Influence Nest Predation Rates of Olfactory Predators? Nest predation by olfactory predators in prairies and open fields Nest predation by olfactory predators in savannas Nest predation by olfactory predators within forests Impact of edge habitat on olfactory predators Using the Physics of Airflow to Redefine Common Ecological Terms Examples from forest ecology of the confusion that can be created by ambiguous definitions What is a forest patch or habitat patch? What is a forest interior? What is a forest edge? How far does a forest edge extend into a forest? What is a forest clearing? Benefits of defining ecological terms based on the physics of airflow Epilogue Dangers posed by depositional odor trails Dangers posed by odor plumes Can the olfactory-concealment theory help guide future research and provide answers to questions that heretofore have lacked explanation? Does the olfactory-concealment theory have any applied value? References Appendix 1 Latin Names of Species Mentioned in this Book Appendix 2 Symbols Used in this Book Appendix 3 Forces Controlling Wind Speed and Direction Appendix 4 Pasquill's System for Measuring Atmospheric Stability Index