Trade-offs between suitability and findability

The ultimate purpose of finding, examining, and consuming behaviors is, of course, to increase the probability that the insect (or its offspring) consumes hosts on which fitness, i.e., developmental rate, survivorship and/or fecundity, are maximized (Jaenike, 1978 Mitchell, 1981 Rausher, 1983). These fitness components are influenced by such plant characteristics as nutritional quality, presence or absence of toxins, and exposure to natural enemies, which collectively determine the host plant s suitability. Although documented cases are yet few, it is generally hypothesized that the acceptability of plant cues is positively correlated with suitability. 

Plant suitability is not the only factor that determines plant use by herbivores. Plant findability - the probability that a plant will be found - is also important. The concept of findability is similar to plant apparency (Feeny, 1976), except that findability is defined in terms of the behavior and sensory 

The same decrease in acceptance thresholds as was observed by Singer (1982) 

The prediction that abundance of more suitable hosts affects the acceptability of less suitable ones is borne out by data on apple maggot flies (Roitberg et al., 1982). Apples that have never received an egg are thought to be more suitable due to lack of intraspecific competition than are apples containing an egg. In trees with high rather than low densities of unused apples, flies are less likely to reach a behavioral state where used apples stimulate oviposition (see also Prokopy etal., Chapter 11). 

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