Species specificity in photoperiodic control of nymphal development in four species of cricket from north-west China

Photoperiodic regulation of nymphal development was examined in four species of cricket collected in the Xinjiang‐Uygur Autonomy Region, China (approximately 43°N, 81–89°E). Fifty percent of individuals of Modicogryllus frontalis reared at 28°C reached adulthood in approximately 80 days in conditions of 11 h light : 13 h dark (LD 11:13) to 14:10, and in approximately 95 days under LD 15:9 to 16:8. Melanogryllus desertus started adult emergence earliest under LD 16:8 at 28°C, but some individuals required much longer to mature, and thus two peaks of adult emergence occurred at approximately 60 and 160 days after hatching. More individuals hatched during the late peak in LD 18:6 than in LD 16:8. The mean nymphal period was approximately 100 days in LD 11:13 to 14:10. Both species showed short‐day type photoperiodic responses, but Mo. frontalis developed faster than did Me. desertus. The latter occupied a wider range of habitat conditions and was more variable in life cycle than the former. Modicogryllus burdigalensis started adult emergence earliest in LD 16:8 at 28°C in the six photoperiods tested, most adults emerging within 60 days. The mean nymphal period was 80 days in LD 15:9, 135 days in LD 14:10 and 80–100 days in LD 11:13 to 13:11, showing an intermediate type of photoperiodic response. Acheta domesticus was a long‐day type species, and the proportion of delayed individuals increased with decreasing photoperiod. In the dry climate of Xinjiang‐Uygur, nymphal overwintering seems to be successful in all of the four different patterns of nymphal development.