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 between macroptery and time spent calling in the wing-dimorphic cricket, Gryllus firmus. The results of previous studies have shown that, under optimal conditions, the proportionate time that males spend calling (with respect to neighbouring males) is directly associated with female attraction, and that micropterous (short-winged: SW) males call longer than macropterous (long-winged: LW) males (Crnokrak & Roff 1995, Animal Behaviour, 50, 1475-1481). Because crickets were examined under optimal 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 intake 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 groups, 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 towards the SW male. Cumulative call distributions showed that LW males called little after 10 days of adult life; the amount of time SW males spent calling seemed constant for the duration of the experiment. Copyright 1998 The Association for the Study of Animal Behaviour
Crnokrak
P
Department of Biology, McGill University
Roff
DA