Alternative mating strategies in a desert grasshopper: a transitional analysis

Abstract

We describe between- and within-individual variation in signalling behaviour for a population of male Ligurotettix coquilletti in a North American desert. For each observation date individual males were categorized as actively-signalling or inactive by the amount and regularity of their stridulation and their signalling location. Few males were active or inactive on all dates they were observed. By comparing the behaviour of individuals on consecutive observation dates, we identified the primary ways that individuals changed between active signalling and inactive behaviour. Behavioural transitions were frequently associated with movement between bushes. Inactive males became active upon moving to a vacant bush, and lone active males often became inactive after moving to a bush containing other males. Male-male aggression (primarily chases involving no contact between the participants, or only very brief contact) had a pronounced, short-term effect upon the signalling behaviour of males that received an attack. Approximately 33% of these recipients that had been stridulating became silent immediately following the chase. However, chases did not markedly alter the behaviour of recipients on the following observation date. Recipients were no more likely to change from inactive to active behaviour than vice versa between the observation dates immediately preceding and following the day of the chase. Although the transition analysis failed to detect marked behavioural changes among recipients, analyses based on longer periods of time revealed that males observed to be recipients were more likely to display inactive behaviour and less likely to mate than males observed to be initiators of aggression.