Sex-specific speed–accuracy trade-offs shape neural processing of acoustic signals in a grasshopper

Abstract

Speed–accuracy trade-offs—being fast at the risk of being wrong—are fundamental to many decisions and natural selection is expected to resolve these trade-offs according to the costs and benefits of behaviour. We here test the prediction that females and males should integrate information from courtship signals differently because they experience different pay-offs along the speed–accuracy continuum. We fitted a neural model of decision making (a drift–diffusion model of integration to threshold) to behavioural data from the grasshopper Chorthippus biguttulus to determine the parameters of temporal integration of acoustic directional information used by male grasshoppers to locate receptive females. The model revealed that males had a low threshold for initiating a turning response, yet a large integration time constant enabled them to continue to gather information when cues were weak. This contrasts with parameters estimated for females of the same species when evaluating potential mates, in which response thresholds were much higher and behaviour was strongly influenced by unattractive stimuli. Our results reveal differences in neural integration consistent with the sex-specific costs of mate search: males often face competition and need to be fast, while females often pay high error costs and need to be deliberate.

Sensory biases in response to novel complex acoustic signals in male and female grey treefrogs, Hyla chrysoscelis

“…On the one hand, in many cases, novel elements placed at the end of an existing signal are more effective at eliciting a response than those at the beginning of the signal [24,25]. Such findings may be explained by neural processing similar to a drift-diffusion model, in which elements at the beginning of a signal are weighted more heavily than those at the end, and negative weighting on novel components is stronger than the positive weighting of typical conspecific signal elements [56][57][58]. On the other hand, in some cases, leading novel signal elements generate neural accommodation that improves response to subsequent species-typical signal components [59] or function as alerting elements [60].…”

Acoustic signalling in Orthoptera

“…Choice may sometimes be more to do with rejecting males that are unsuitablee.g. heterospecifics, injured males or those with developmental problemsrather than selecting a high-quality mate (Clemens et al, 2017;Clemens et al, 2021). The costs and benefits for the female may also be affected by male manipulation of, for example, egg laying rates or longevity, via factors transferred in the spermatophore, rather than her choice of mate (e.g.…”