Reciprocity in animals

Reciprocity has been a controversial topic in behavioral ecology for over 40 years. How often is cooperation between animals stabilized by conditional responses to each partner's helping (reciprocity)? How often are cooperative investments explained by product returns (pseudo-reciprocity)? I argue that, in many real-world cases, helping increases both reciprocal help and byproduct returns. When you live in a group and you help a "friend" survive, you might simultaneously increase their willingness to reciprocate help, their ability to reciprocate help (because they are alive), and many other byproduct benefits of their existence (e.g. they help you notice if there is a predator). These causal factors cannot be easily disentangled, and these cases cannot be clearly categorized using traditional labels in behavioral ecology, yet these scenarios may be common. I will review this controversial topic using recent work in food-sharing vampire bats and cooperatively breeding superb starlings.