Data from: Does male reproductive effort increase with age? Courtship in fiddler crabs

Theory suggests that reproductive effort generally increases with age, but
life history models indicate that other outcomes are possible. Empirical
data are needed to quantify variation in actual age-dependence. Data are
readily attainable for females (e.g. clutch/egg size), but not for males
(e.g. courtship effort). To quantify male effort one must: (a)
experimentally control for potential age-dependent changes in female
presence; and, crucially, (b) distinguish between the likelihood of
courtship being initiated, the display rate, and the total time invested
in courting before stopping (‘courtship persistence’). We provide a simple
experimental protocol, suitable for many taxa, to illustrate how to obtain
this information. We studied courtship waving by male fiddler crabs, Uca
annulipes. Given indeterminate growth, body size is correlated with age.
Larger males were more likely to wave at females and waved more
persistently. They did not, however, have a higher courtship rate
(waves/second). A known female preference for males with higher display
rates explains why, once waving is initiated, all males display at the
same rate.