Meta-analysis reveals that animal sexual signalling behaviour is honest and resource based

When signalling to attract mates, animals in poor condition could signal less to conserve resources (ability-based signalling) or more to maximize short-term reproductive success (needs-based signalling). Meta-analysis of 147 animal species shows that signalling is predominantly an honest indication of ability, although there is a trend for needs-based signalling when comparing old with young unmated individuals. Animals often need to signal to attract mates and behavioural signalling may impose substantial energetic and fitness costs to signallers. Consequently, individuals often strategically adjust signalling effort to maximize the fitness payoffs of signalling. An important determinant of these payoffs is individual state, which can influence the resources available to signallers, their likelihood of mating and their motivation to mate. However, empirical studies often find contradictory patterns of state-based signalling behaviour. For example, individuals in poor condition may signal less than those in good condition to conserve resources (ability-based signalling) or signal more to maximize short-term reproductive success (needs-based signalling). To clarify this relationship, I systematically searched for published studies examining animal sexual signalling behaviour in relation to six aspects of individual state: age, mated status, attractiveness, body size, condition and parasite load. Across 228 studies and 147 species, individuals (who were predominantly male) invested more into behavioural signalling when in good condition. Overall, this suggests that animal sexual signalling behaviour is generally honest and ability-based. However, the magnitude of state-dependent plasticity was small and there was a large amount of between-study heterogeneity that remains unexplained.

Automated summary

Animal sexual signalling behavior is generally honest and ability-based, with individuals investing more in behavioral signaling when in good condition. However, there is also some impact of needs-based signaling in certain situations. Individual state influences signaling effort, with individuals in good condition tending to invest more in signaling behavior.