Effects Of Temperature And Photoperiod On The Growth, Development And Egg Diapause Of Three Grasshopper Species In Inner Mongolia

The effects of temperature (13, 18, 23, 28, 33℃) on three grasshopper species were conducted in Inner Mongolia grassland. The results showed that under the condition of middle photoperiod (L12: D12), temperature had no significant effect on the percentage of egg diapause of Dasyhippus barbipes (F.-W.) and Oedaleus decorus asiaticus B.-Bidenko but Chorthippus fallax(Zub.). High temperature (28 and 33℃) restrained the egg diapause of C. fallax.Under the condition of (28±1)℃during the day time and (23±1)℃at night, photoperiods had no significant effect on the development, eclosing rate and reproduction but the survival of D. barbipes (F.-W.) and O. d. asiaticus B.-Bidenko. D. barbipes and O. d. asiaticus had the fastest developmental rates at middle photoperiod (L12: D12) while short photoperiod (L8: D16) was beneficial to the development of C. fallax, followed by middle photoperiod. D. barbipes had the highest eclosing rate at middle photoperiod while long photoperiods (L16: D8) were beneficial to eclosing of O. d. asiaticus and C. fallax. Photoperiods had significant effects on oviposition of three grasshopper species. Middle and long photoperiods were beneficial to oviposition of D. barbipes and O. d. asiaticus while short and middle photoperiods were beneficial to oviposition of C. falla.Different photoperiods could induce egg diapause of D. barbipes and O. d. asiaticus and diapause rates reached to 100%. However, they did not affect significantly the egg diapause of C. fallax and the rate of hatching increased with the prolonging of day length from 8h to 16h.