ABSTRACT
The field of behavioral ecology includes a diverse range of problems having to do with the developmental, physiological, genetical, and ecological bases of behavior. Of interest here is the context in which helping behavior evolved. One plausible hypothesis is that helping arose as a byproduct of selection in some other context, such as on parents to feed begging offspring. Second, helping might be present in a particular species as a consequence of phylogenetic inertia. Helpers lighten the load of breeders. In at least ten species, breeders reduce their feeding rates when assisted by helpers. This "lightening of the load" of breeders will have fitness consequences only if it increases breeder survival, reproductive success, or both. Patterns of helping behavior that appear to have been modified or "fine-tuned" by selection suggest adaptation by design and thus that helping is a direct product of natural selection.
