关键词: 艾虎, 天敌动物, 饥饿风险, 捕食风险, 食物斑块, 取食行为

Abstract: In order to investigate the trade-off between the starvation risk and predation risk in the feeding process of the steppe polecat (Mustela eversmanni),the feeding behaviors of 6 adult steppe polecats in the patches with different food quantities were observed under three predation risks and four starvation levels by using two-choice test in the laboratory, with upland buzzard (Buteo hemilasius) as predator. The results showed that under no predation risk,firstly,all of the polecats took equal food in different patches with same frequency whether they were starved for 0 or 1 day, but they spent longer feeding time in the patch with more food (P<0.05); secondly,they spent more time and obtained more food in the patch with high quantity (P <0.05), but their feeding frequency was not different when they were deprived food for 2 or 3 days (P> 0.05). When facing lower predation risks,all of the animals only got food from the patch with less food and no upland buzzard under 4 different starvation levels (P<0.05). And when there were high risks,polecats had to use the food from the patch with an upland buzzard; they spent same time in two different patches under the no starvation condition, but spent longer time in the patch with food and upland buzzard than in the patch without food and enemy when starved for 1,2 or 3 days (P<0.05). It was also found that their food intake amount was proportional,but feeding time and frequency were inversely pro orti nal t thei star atio time what ver t e lev ls of he pr dati n risk they facing (P < 0. 05). Under the same starvation conditions,polecats took the same amount food in all of 3 predation risks,but compared to no predation risk,low and high predation risk made them decrease their active time and feeding frequency significantly (P <0. 05). These results indicated that the polecat could make a trade-off between the starvation risk and predation risk according to the need for energy. They were inclined to the risk-aversion when the starvation risk was lower than the predation risk and preferred to risk-proneness when the starvation risk was higher than the predation risk. It could be concluded that the feeding strategy of the polecat was to decrease the active time and energy consumption and get the largest net energy in unit time.

Key words: Food patch, Feeding behavior, Nature enemy, Predation risk, Steppe polecat (Mustela eversmanni), Starvation risk