Urban pest cockroaches (Supella longipalpa), like many omnivores (Singer and Bernays, 2003), balance their diet by selecting among available foods rather than by trying to obtain all nutrients from one food type (Cohen et al., 1987). Periplaneta fuliginosa is described as a "cafeteriastyle eater" that will sample several types of food before concentrating on one (Appel and Smith, 2002). Other species known to have a varied diet in natural habitats, like Parcoblatta (Table 4.1), may do the same thing. Laboratory studies indicate that cockroaches are capable of selecting their diet relative to nutrient demand at every point in the lifecycle. Within a species, foraging behavior and dietary preferences vary with sex and ontogeny, and undergo dramatic changes correlated with reproductive and developmental cycles. In the field, it is possible that these predilections are also influenced by the seasonal availability of specific foods. Just after a local mast fruiting, for example, their diet may be higher in sugars and yeasts, and lower in fiber. When fruit is not available or their needs change, they may rely on less nutritious, higher-fiber foods such as litter or bark, or seek items that provide specific nutrients.
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