Signal value of male courtship effort in a fish with paternal care

Male courtship behaviour is known to correlate with body condition and other aspects of male phenotypic or genetic quality. Females often prefer males that express the most intense or elaborate displays, although recent findings indicate that this should not always be the case; males may be strategic in their courtship displays, signal dishonestly or deplete their energy reserves with intense courting. To study reliability of courtship effort as a mate choice signal, I assessed multiple aspects of male courtship using wild-caught sand gobies, Pomatoschistus minutus, in a controlled laboratory setting. I found consistent and repeatable between-male differences in courtship. However, females did not show a significant preference for males that courted intensively. Furthermore, other assessed male traits with a previously demonstrated role in sexual selection were not correlated with courtship effort. This indicates that courtship displays did not reliably signal male quality. The results also suggest that even when courtship has potential to convey useful information, females may have to trade between courtship and other cues they use in mate choice. Hence, to gain a more complete understanding of the selection regime acting on male courtship behaviour, and female preference for it, one should simultaneously investigate multiple factors that can affect female mating behaviour.

► Evidence on signal value of male courtship effort has been mixed.
► A broad approach is needed to efficiently evaluate courtship as a mate choice cue.
► Such an approach revealed lack of a strong link between courtship and measures of male quality.
► Females did not prefer intense courtship displays.
► The results encourage simultaneous consideration of multiple sexually selected signals.