I. Resource Quality
A. Resource Requirements
B. Variation in Food Quality
C. Plant Chemical Defenses
D. Arthropod Defenses
E. Factors Affecting Expression of Defenses
F. Mechanisms for Exploiting Variable Resources
II. Resource Acceptability
III. Resource Availability
A. Foraging Strategies
ALL ORGANISMS ARE EXAMPLES OF NEGATIVE ENTROPY, IN CONTRAST TO the tendency for energy to be dissipated, according to the Second Law of Thermodynamics. Organisms acquire energy to collect resources and synthesize the organic molecules that are the basis for life processes, growth, and reproduction. Hence, the acquisition and concentration of energy and matter are necessary goals of all organisms and largely determine individual fitness.
Insects, like other animals, are heterotrophic (i.e., they must acquire their energy and material resources from other organisms; see Chapter 11). As a group, insects exploit a wide range of resources, including plant, animal, and detrital material, but individual organisms must find and acquire more limited, appropriate resources to support growth, maintenance, and reproduction.
The organic resources used by insects vary widely in quality (nutritional value), acceptability (preference ranking, given choices and tradeoffs), and availability (density and ease of detection by insects), depending on environmental conditions. Physiological and behavioral mechanisms for evaluating and acquiring food resources, and their efficiencies under different developmental and environmental conditions, are the focus of this chapter.
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