In cricket calling songs, pulse rate is often the feature that allows females to home on the songs of conspecific males while ignoring those of other species. A previous study of the sibling species Gryllus rubens Scudder and G. texensis Cade & Otte from western Florida showed unexpected effects of developmental conditions and parental generation on the pulse rates of their songs. The current study tested for these and other effects in G. rubens from Gainesville, FL, and G. texensis from Dallas, TX. In both species, sibships from different field-fertilized females differed significantly in the effects of rearing environment on the pulse rates of their songs. Tests for effects of nymphal diapause and adult age were negative. Hybrids between the two species produced pulse rates intermediate to the rates of the control crosses. Males of G. rubens reared at 32°C produced faster pulse rates (at a standard temperature) than those reared at 25°C. Furthermore, pulse rates of field-collected males in this study and of field-collected and laboratory-reared males in the previous study increased in rough proportion to the known and estimated temperatures during nymphal development.