Costs of Anti-predator Behavioral Defenses
Prey become aware of potential predator encounters by using information about the predators The responses of prey to predator signals allow prey the flexibility to react to varying levels of predation risk. Responses to predation risk by prey, such as predator avoidance and escape behaviors, have been viewed by behavioral ecologists as the result of decision making by prey. Decision making by prey is dependent on 1. the ability of prey to assess the presence of a predator, 2. the ability of prey to distinguish among predators and/or the degree of risk presented by a predator, 3. the availability of one or more defensive behaviors for prey to choose from and their relative effectiveness against a particular predator, and 4. the existence of trade-offs (predator avoidance or escape versus resource use, e.g. feeding or mating) that make decision-making necessary.
Several studies have shown that prey appear to assess the degree of risk, which implies the ability to assess the likelihood of predator success. Prey also may vary their responses to a given predator depending on the degree of risk as reflected in the predator's proximity to the prey and the abundance of the predator. However, very few studies have experimentally shown how prey respond to the degree of risk presented by the predator, probably because only a few studies have addressed which signals determine the prey's behavior under different risk situations, and such signals have rarely been related to the prey's fitness. The costs of anti-predator behavior have generally been measured by comparing the effect of predators against a no predator control using, for example, food eaten by the prey as the currency of costs. However, relatively few studies have related this effect to the prey's fitness. Costs of anti-predator behavior can also arise when prey move to a new microhabitat as a way of escaping predators if the new microhabitat is occupied by other predators.
Thus, this research project examines decision making by prey by determining whether prey can specifically recognize predators, whether prey assess the degree of predation risk, how prey choose from different anti-predator behaviors and their relative effectiveness against different predators, and the trade-offs between anti-predator behaviors and lost opportunity for feeding. By examining these aspects of prey decision the hypothesis that anti-predator behavioral defenses represent a predation risk assessment which produces a favorable cost:benefit relationship to the prey will be tested. To test if the use of anti-predator behavioral defenses represents a predation risk assessment which produces a favorable cost:benefit relationship to the prey, the following two objectives will be address: 1. Determine if prey are capable of a qualitative and quantitative evaluation of predation risk. 2. Determine the costs of anti-predator behavioral responses by the prey.
To address if prey are capable of a qualitative and quantitative evaluation of predation risk, experiments will be conducted to determine whether a. prey distinguish between predators and abiotic factors, b. prey distinguish between predators and non-predators (herbivores), c. prey distinguish between predator species, and d. there is a relationship between predation risk and predator signals. To determine the costs of anti-predator behavioral responses by the prey experiments will conducted to a. evaluate if and how often caterpillars leave their host plant in the presence of predators, and b. evaluate the costs of dropping behavior and of hanging from a silk thread behavior when encountering a predator.
Participants: I. Castellanos/P. Barbosa
Several studies have shown that prey appear to assess the degree of risk, which implies the ability to assess the likelihood of predator success. Prey also may vary their responses to a given predator depending on the degree of risk as reflected in the predator's proximity to the prey and the abundance of the predator. However, very few studies have experimentally shown how prey respond to the degree of risk presented by the predator, probably because only a few studies have addressed which signals determine the prey's behavior under different risk situations, and such signals have rarely been related to the prey's fitness. The costs of anti-predator behavior have generally been measured by comparing the effect of predators against a no predator control using, for example, food eaten by the prey as the currency of costs. However, relatively few studies have related this effect to the prey's fitness. Costs of anti-predator behavior can also arise when prey move to a new microhabitat as a way of escaping predators if the new microhabitat is occupied by other predators.
Thus, this research project examines decision making by prey by determining whether prey can specifically recognize predators, whether prey assess the degree of predation risk, how prey choose from different anti-predator behaviors and their relative effectiveness against different predators, and the trade-offs between anti-predator behaviors and lost opportunity for feeding. By examining these aspects of prey decision the hypothesis that anti-predator behavioral defenses represent a predation risk assessment which produces a favorable cost:benefit relationship to the prey will be tested. To test if the use of anti-predator behavioral defenses represents a predation risk assessment which produces a favorable cost:benefit relationship to the prey, the following two objectives will be address: 1. Determine if prey are capable of a qualitative and quantitative evaluation of predation risk. 2. Determine the costs of anti-predator behavioral responses by the prey.
To address if prey are capable of a qualitative and quantitative evaluation of predation risk, experiments will be conducted to determine whether a. prey distinguish between predators and abiotic factors, b. prey distinguish between predators and non-predators (herbivores), c. prey distinguish between predator species, and d. there is a relationship between predation risk and predator signals. To determine the costs of anti-predator behavioral responses by the prey experiments will conducted to a. evaluate if and how often caterpillars leave their host plant in the presence of predators, and b. evaluate the costs of dropping behavior and of hanging from a silk thread behavior when encountering a predator.
Participants: I. Castellanos/P. Barbosa
