东方田鼠家族群对成员个体觅食行为的影响

植食性哺乳动物在分享社群觅食带来好处的同时,是否因个体间的相互干扰而影响其摄入率。在新鲜马唐叶片构建的均质密集食物斑块上,测定东方田鼠家族群成员个体在食物斑块上的觅食行为序列过程及行为参数,检验家族群存在对成员个体觅食行为的影响。结果发现,东方田鼠家族群雌、雄成员个体的觅食行为参数均无显著差异。然而,与单只个体相比,家族群觅食尽管能显著地缩短成员个体的觅食决定时间,但却显著地降低了成员个体的摄入率。分析觅食行为参数觅食中断时间发现,相较于单只个体,家族群成员个体间因相互干扰而引起的觅食中断时间的增加,不但增大了收获每口食物的时间,而且导致其摄入率下降。检测家族群成员个体各警觉行为动作参数,发现,成员个体间的相互干扰能引致个体的一般扫视、盯视及嗅闻动作时间比例显著增大,尽管直立扫视和静听动作时间比例减少显著,但并未使个体的觅食中断时间减小。结果充分说明,东方田鼠家族群成员个体间的相互干扰能使个体觅食行为参数发生变异,导致觅食中断时间增加,摄入率降低。

The effects of family groups on individual foraging behavior in reed voles (Microtus fortis)

Herbivorous mammals benefit from foraging in family groups through the sharing of vigilance information and the dilution of the individual risks of being preyed upon; however, interference competition may reduce their intake rates. To evaluate the effects of family foraging on the individual foraging behavior of reed voles (Microtus fortis), the behavioral sequences and parameters of the voles'' foraging on concentrated homogenous food patches consisting of fresh crabgrass leaves (Digitaria sanguinalis) were measured. The results showed that there is no significant difference in foraging behavior between female and male among family groups; however compared to a lone individual, individuals in family groups had significantly shortened foraging decision times, but markedly reduced intake rates. Analyses showed that, compared with the lone individual, the foraging interruption times of individuals increased significantly in family groups, but their intake rates declined significantly as a result of the greater amount of time spent on searching for adjacent food items. Analyses of the individual vigilance time showed that interference competition triggered by others individuals in family groups significantly increased the proportion of vigilance time spent on scanning, staring, and sniffing. While the proportion of vigilance time spent on upright scanning and listening decreased for individuals in family groups, the interruption times of individuals did not decrease significantly. These results revealed that the interference competition among individuals in family groups triggered variations in the parameters of the foraging behavior of the reed voles, increasing their foraging interruption times and decreasing their intake rates.