Abstract:The cricket species Velarifictorus aspersus displays distinct wing dimorphism-individuals are either micropterous with much degenerate wings or macropterous with fully developed wings. In this paper, we compared the short and long-winged morphs based on several adult measurements, including fresh weight, head width, wing length and length of hind femur. We did not find significant difference between the two morphs for any of the four measurements other than wing length. In order to find out possible relationship between environmental factors and wing degeneration, we studied the effects of photoperiod, temperature and density on wing development. We found out that about 10% of the individuals, both females and males, would develop into macropterous morph when reared in photoperiods shorter than 14 hours, and the percentage of macropterous individuals would greatly increase, in both males (31.6%) and females (40%) when exposed to an increased photoperiods of 16 hours. However, the same trend was not observed at unusually long photoperiod (LD 20∶4 h), whether successively treated in light or dark conditions. A long-day shift (from LD 12∶12 h to LD 16∶8 h), occurring at 20 or 40 days after hatching, exhibited strong macropters inducing effect, whereas transfer of nymphs from LD 16∶8 h to LD 12∶12 h at 20 days after hatching resulted in significantly decreased percentage of macropters. However, when transferred from LD 16∶8 h to LD 12∶12 h at 30 days after hatching, the percentage of nymphs to develop into macropters was still significantly increased. These results suggest that changes in photoperiod can have varying influences on wing development, depending on the timing and direction of the transfer. In experiment treating nymphs with various temperatures, low temperature (20 ℃) caused all nymphs to emerge as micropters while high temperature (25 ℃, 30 ℃) induced macropters. In crowding experiment, rearing of nymphs separately at 25 ℃, under either LD 12∶12 h or LD 16∶8 h, produced no macropter while, and the number of macropters increased considerably as the per container density was increased to 2 and 5 nymphs, especially under LD 16∶8 h, suggesting that density played an important role in the determination of the wing morphs, and high density induced macropters.