Is cricket courtship song condition dependent?

Females of the Texas trilling field cricket, Gryllus texensis, show mating preferences based on mate courtship song. To test experimentally the condition dependence of courtship song, we attempted to manipulate male condition via the diet. When the diet was manipulated at the adult moult, there was no effect on subsequent male courtship song or male condition measured as residual mass. When the diet was manipulated three moults prior to the adult moult, there was a significant effect on male residual mass, but no differences in courtship song were observed. To gain a second measure of condition in the diet-manipulated-as-nymphs group, we extracted their fat using petroleum ether in a refluxing Soxhlet apparatus. Crickets reared on the poor diet showed a clear relationship between the residual mass measure of condition and condition measured as energetic fat reserve, whereas the two measures of condition were unrelated in crickets reared on the good diet. Courtship song was unrelated to diet, fat reserve or residual mass. We conclude that courtship song does not reflect male condition in the laboratory despite its energetic cost. When given a mating opportunity it is probably in the evolutionary interest of males in poor condition to signal at as high a rate as males in good condition. (C) 2001 The Association for the Study of Animal Behaviour.