THE CONTINGENCY OF FITNESS - AN ANALYSIS OF FOOD RESTRICTION ON THE MACROPTERY-REPRODUCTION TRADE-OFF IN CRICKETS

We examined the effect of food limitation on fitness trade-offs betwee n macroptery and time spent calling in the wing-dimorphic cricket, Gry llus firmus. The results of previous studies have shown that, under op timal conditions, the Proportionate time that males spend calling (wit h respect to neighbouring males) is directly associated with female at traction, and that micropterous (short-winged: SW) males call longer t han macropterous (long-winged: LW) males (Crnokrak & Roff 1995, Animal Behaviour, 50, 1475-1481). Because crickets were examined under optim al Conditions, these studies did not attempt to address how or whether fitness trade-offs change with the environment. In the present study, we allowed crickets ad libitum access to water, but restricted food i ntake to the minimum amount that would keep them alive for 20 days. On average, SW males called longer than LW males On 18 of 20 days in the stressed group, and 17 of 20 days in the control group. For both grou ps, SW males also attracted more females more often than did LW males. Although the absolute call durations decreased in the stressed group compared with the control group, the relative call durations remained approximately the same, as did the proportion of females moving toward s the SW male. Cumulative call distributions showed that LW males call ed little after 10 days of adult life; the amount of time SW males spe nt calling seemed constant for the duration of the experiment. (C) 199 8 The Association for the Study of Animal Behaviour.