Tab. 1: Geographical, temperature and chemical features of sites on Bear Island and Spitsbergen

In arctic populations of Macrothrix hirsuticornis life cycles are mainly governed by temperature. This was found by using laboratory cultures in combination with the analysis of population samples from waters in Svalbard. In arctic waters ex-ephippio-++ usually produce gamogenetic F1-++ together with a high percentage of oo, which have to fertilize the resting eggs. Temperatures around 14°C, which are very rare in waters of Svalbard, will induce parthenogenetic oo in the F1 and even the F2-generation, a mode of reproduction normally found in Macrothrix-populations of Central Europe. This was found in laboratory cultures of M. hirsuticornis from Bear Island, and there was evidence, that a similar cycle occurs in warm wells in Spitsbergen. The arctic distribution of M. hirsuticornis mainly depends on temperature, which regulates the speed of individual development. But this can only be understood together with the length of time, during which suitable life conditions are given. Physiological adaptations to life in waters in high latitudes could not be found, in spite of the extreme northern occurrence of M. hirsuticornis.粗毛大尾溞（Macrothrix hirsuticornis）的北极种群生活周期主要受温度调控。该结论通过实验室培养结合对斯瓦尔巴群岛（Svalbard）水域种群样本的分析得出。在北极水域中，脱卵鞍个体通常会产生有性生殖子一代，同时伴随高比例的需受精卵，此类卵需通过受精完成发育。在斯瓦尔巴群岛水域中极为罕见的14℃左右的温度，会诱导子一代乃至子二代产生孤雌生殖个体——这种生殖模式常见于中欧的粗毛大尾溞种群。该现象在来自熊岛（Bear Island）的粗毛大尾溞实验室培养物中得到验证，且有证据表明，斯匹次卑尔根（Spitsbergen）的暖水井中也存在类似的生活周期。粗毛大尾溞的北极分布范围主要依赖温度，温度调控着个体发育速率，但这一规律需结合适宜生存条件的持续时长才能得到完整阐释。尽管粗毛大尾溞的分布范围极北，但并未发现其对高纬度水域生活的生理适应性。