低氧对不同海拔雄性高原鼠兔生殖机能若干指标的影响

为了探讨低氧对不同海拔雄性高原鼠兔(Ochotona curzoniae)生殖机能的影响,测定了不同海拔雄性高原鼠兔繁殖期睾丸指数,附睾指数,附睾尾精子数量,精子活率和睾丸组织LDH-C4和LDH比活力及其比值;同时还统计了不同海拔雌性高原鼠兔胎仔数。结果显示:不同海拔高原鼠兔睾丸指数、睾丸组织LDH-C4比活力和LDH比活力均无显著差异(P﹥0.05);而高海拔高原鼠兔附睾指数和附睾尾精子数量均极显著高于低海拔高原鼠兔(P﹤0.01);高海拔高原鼠兔精子活率和LDH-C4比活力/LDH比活力均显著高于低海拔高原鼠兔(P﹤0.05);而高海拔雌性高原鼠兔胎仔数却显著低于低海拔高原鼠兔(P﹤0.05)。以上结果表明,随着海拔的升高,低氧对高原鼠兔精子生成和精子活率不仅没有抑制,反而明显提高,但低氧对雌性高原鼠兔胎仔有显著影响,随着低氧程度提高,胎仔数下降。     

Seasonal variations in the time–activity budget of Royle’s pika in the Western Himalaya,India

ABSTRACT

The time–activity budget of a species has ecological relevance because natural selection often favours individuals that utilise their time most efficiently. Details of time–activity budgets can provide information on how animals allocate time to their various activities through the day and during different seasons to most efficiently cope with varying energy demands and environmental changes that may threaten their survival. Efficient use of time–activity budget is also crucial for alpine small mammals, which live in a highly seasonal environment with restricted periods in which to gain energy and successfully reproduce. Hence, variations in the time–activity budget of the high-elevation lagomorph Royle’s pika (Ochotona roylei) were analysed during different seasons over 2 years across an elevational gradient (2900–3680 m). Seven behavioural conditions were recorded in adult and juvenile pikas through daily focal sampling between 0600 and 1900 hrs. Royle’s pika had bimodal activity: animals were most active during the morning and early evening and relatively inactive during midday hours. Adult pikas allocated the largest proportion of their time–activity budget to foraging and the smallest proportion to vocalisation. Greater food availability during the monsoon season encouraged pikas to spend more of their time foraging than on other activities. In the autumn, pikas spent more time on locomotory and musing activities. Vigilance activities were most frequent during midday hours, possibly due to a high risk of predation. Locomotion and foraging were the predominant behaviours of juveniles during the summer and monsoon seasons. Prominent food hoarding activities were not observed in either adult or juvenile pikas. Information on time allocation to different activities during different seasons should provide a baseline for future behavioural ecology and bioenergetic analyses of pikas and help to understand their potential for adaptation to climate change.