| Calliptamus italicus(L.) is a serious plague in arid and semi-arid grasslands of Xinjiang. Previous studies have claimed that its outbreak is closely related to climate warming of Xinjiang. First this paper explores the effect of high temperature increasing on respiratory metabolism, eating and mating behavious of C. italicus. To explore stigma structure and the response of respiratory metabolism of C. italicus to high temperature stress, stigma structure was observed via scanning electron microscope(SEM) and respiratory rate, metabolic rate, CO2 release rate, Q10 and respiratory quotient were measured via a multi-channel insect respiration apparatus(Sable Systems, USA) within a temperature gradient of 15-35℃ with 5℃ intervals. Results showed that stigma characterized outside closed type of C. italicus, with near oval shape. Filter apparatus inside stigmas were clustered, shorted and dense. The rates of respiration, metabolism and CO2 release increase as temperature goes up. The values at 15 are significantly lower than those at ℃the other temperatures(P <0.05), but the values at 35 ℃are significantly higher than those at the other temperatures(P<0.05), which indicates that the conditions below 15 ℃and over 35 both have impact to ℃ C. italicus. However, the values measured from 20℃ to 30℃ are not significantly different(P>0.05), which reveals that this temperature range is suitable to C. italicus development. The second, research aimed to determine the response of the discontinuous gas exchange cycle(DGC) duration in C. italicus to high temperature stress, examined the DGC duration, spiracular closure duration and open duration of C. italicus adults by using Sable Systems from 21℃ to 42℃ with 3℃ intervals. The DGC duration decreased and the DGC frequency increased with the increasing of temperature. The spiracular closure durations from 21 ℃to 33 ℃were not significantly different(P>0.05) with females and males in average decreasing 0.174 min and 0.121 min per 3℃, respectively, while the DGC frequency changes for females and males are same by increasing 0.0022 Hz per 3℃. Over 33℃, spiracular closure durations were significantly decreased, and average decreases for females and males were 2.197 min and 2.189 min per 3℃, respectively, but the DGC frequency increased 0.0120 Hz and 0.0085 Hz per 3℃. Spiracular closure duration at 39 was significantly lower than ℃those at lower temperatures(P<0.05). DGC breathing pattern was completely disappeared at 42℃. With temperature rising, O2 uptake rate and CO2 release rate in C. italicus increased by regulating DGC duration decrease and the DGC frequency increase. The third, research aimed to determine eating and mating behaviors in C. italicus to high temperature stress, the results show that the total food consumption by C. italicus would increase when the temperature varied from 27℃to 36℃, but the total food consumption was going down when the temperature was over 36 ℃, the total food consumption was least at 42℃, but from 27℃ to 42℃ are not significantly different(P>0.05); among 3 gradients of temperatures, the copulation duration was the longest under 27 ℃(15.93±2.25 min), and the shortest under 42(6.01±0.43 min), which showed the trends ℃that the copulation duration was decreased with the increase temperature. This study demonstrated from 21℃ to 33℃ is the optimal condition for C. italicus, it can adapt to higher temperatures by regulating respiratory mechanism in certain temperature ranges, which indicates the C. italicus is still a serious pest to the steppe in Xinjiang under the trend of climate warming. |
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