Selection of interdependent choice of 2 complementary resources

Abstract

In modeling resource choice, resources are commonly categorized as essential, complementary, or substitutable. Most models concerning nonsubstitutable resources have represented each resource as a set of identical options. In reality, nonsubstitutable resources often vary in quality. Biting insects require a bloodmeal host and an oviposition site for reproduction, and expected offspring yield from different hosts and sites varies dramatically. Because both of these resources are necessary, selection may exist for interdependent choice, or bloodfeeding decisions that depend on egglaying site distribution, and vice versa. For example, insects may be selected to feed on hosts near high-quality sites or to lay eggs in sites near high-quality hosts. These decisions may be influenced by resource distribution; some areas may have clusters of high-quality hosts or sites, but the co-occurrence of both resources may be uncommon. In this study, we demonstrate the selective advantage of interdependent choice in heterogeneous environments. A 2-patch model demonstrates that interdependent choice is advantageous when resource quality varies greatly, as threshold acceptable bloodmeal host quality differed most from in a completely random environment when oviposition site quality was highly variable, and with high movement costs. A dynamic state variable model extended this result, demonstrating that spatial correlation in quality between resources is sufficient to select for interdependent choice, and autocorrelation increases the effect of between-resource correlation on behavior. This model also demonstrates that the relationship between the resources influences optimal behavior; highly complementary resources are more likely to select for populations that exhibit interdependent choice.