温度对青海尕海盐湖卤虫发育和种群增长的影响

EFFECTS OF TEMPERATURE ON THE DEVELOPMENT AND POPULATION GROWTH OF BRINE SHRIMP(ARTEMIA PARTHENOGENETICA GAHAI)

1990～ 1999年对尕海卤虫的温度特性研究表明 ,无节幼虫的耐寒力比幼虫期高 - 1 7℃ ,比成虫期高- 0 9℃ ,即无节幼虫的耐寒力最强 ,幼虫对低温最敏感 ;孵化发育起始温度 9 94℃ ,幼虫发育起始温度10 33℃ ,有效积温 (℃·d)前者为 2 2 91± 2 0 8,后者为 2 6 1 2 6± 2 4 1,平均世代发育起点温度 10 2 8℃ ,有效积温 45 8 6 8± 5 7 6 0 ;依据生命表计算得出的各项生态学参数与温度存在显著的函数关系 ,其适温范围基本介于 10℃～ 39℃ ,最适温度介于 2 4 9℃～ 30 5℃ ,种群增长倍数 >2的温度范围在 15℃～ 34℃ ;依据 1993～ 1994和 1997年尕海水域温度测定资料 ,结合上述实验结果 ,得出该卤虫的年世代数为 2 6 7± 0 34个代 ,一年中有4 6 9± 0 43个生殖高峰期 ;最后一个完整世代的起始时间是 8月 10日 ;因积温不足 ,在 9月 1日以后出现的无节幼虫将不能完成到成虫期的发育 ;在 7月中旬至 9月中旬是种群生产力高峰期 ,在此期间种群的加倍时间 <30d ,内禀增长率 >0 0 2d-1,开发潜力最大。

The effects of temperature on the population of the brine shrimp ( A. parthenogenetica gahai) in the Gahai Salt Lake were studied. The major results are as follows. 1) The cold tolerance (TC) test showed that the TC of the nauplii was the strongest, followed by the adult and the larve in whole lifetime. The TC of nauplii was -1 7℃ higher than that of larvae and -0 9℃ higher than that of adults. 2) The adaptive temperature for brine shrimp ranged from 11℃～38℃. The threshold temperature of development (TD) and the effective accumulative temperature (TA) for hatching were 9 94℃ and (22 91 ±2 08)℃·days, respectively. The TD and TA for the larva were 10 33℃ and (261 26±24 1)℃·days, respectively, for a whole generation were 10 28℃and (458 68±57 60)℃·days, respectively. 3) The population net reproduction rate( R o ),the intrinsic rate of natural increase ( r m ),the mean generation time ( T ),the finite rate of increase ( λ) and the days for population doubling time ( t ) of the brine shrimp were determined over a temperature range of 19 ℃～34 ℃. The results shown that the optimum temperature (℃) for R o, r m, λ and t were 25 8,29 8, 30 5 and 29 02, respectively. The maximum values of R o, r m and λ were 54 86 ind., 0 11 day -1 and 1 1 day -1 , respectively. The minimum value of \%t\% was 4 73 days. In the temperature range of 14 3℃～37 3℃, the value of \%T\% was in a range of 96 77～16 10 days. 4) Based on the data about the water temperature in the Gahai Salt Lake, Qinghai Province, which was collected from 1993 to 1994 and in 1997, it was estimated that the annual number of generation of A. parthenogenetica gahai and the annual number of the reproductive peak were 2 67±0 34 and 4 69±0 43, respectively, in a year. The peak of nauplii of first generation was from April 20 to 28 The last generation began on August 10 The first reproductive peak was from June 18 to 25 The last reproductive peak was from September 12 to 17. The nauplii hatching after September 1, could not complete the development from nauplii to adult because of insufficient habitat effective accumulative temperature. During a period from July 11 to September 20, there was a relatively high population productivity. In this case, doubling of the population would take less than 30 days, and the intrinsic rate of natural increase was over 0 02 day -1 .