Big houses, big cars, superfleas and the costs of reproduction

The assumption of costs of reproduction were a logical necessity for much o f the early development of life history theory. An unfortunate property of 'logical necessities' is that it is easy to also assume that they must be t rue. What if this does not turn out to be the case? The existence and unive rsality of costs of reproduction were initially challenged with empirical d ata of questionable value, but later with increasingly strong theoretical a nd empirical results. Here. we discuss Ken Spitze's 'superfleas', which rep resent what we consider to be the strongest empirical challenge to the univ ersality of costs, then offer a possible explanation for their existence.