东方田鼠社群气味对家族群成员个体觅食行为的影响

Effects of social group odors on individual foraging behavior of family groups in reed voles (Microtus fortis)

东方田鼠家族群成员个体的觅食行为是否因食物斑块存有家族群自身及非亲缘家族群气味而发生变异,进而影响其摄入率。在新鲜马唐叶片构建的均质密集食物斑块上,分别配置家族群自身巢垫物及非亲缘家族群巢垫物作为社群气味,测定东方田鼠家族群在食物斑块觅食时,其成员个体觅食行为的序列过程及参数,检验家族群自身气味及非亲缘家族群气味对成员个体觅食行为的影响。结果表明,家族群自身气味能显著地缩短本群成员个体的觅食决定时间,通过减少成员个体的嗅闻及直立扫视动作时间比例、增大一般扫视、盯视及静听动作时间比例,降低觅食中断时间比例,提高其摄入率;而非亲缘家族群气味则能显著地延长家族群成员个体的觅食决定时间,通过增大家族群成员个体的嗅闻和一般扫视动作时间比例、减小直立扫视、盯视及静听动作时间比例,增大觅食中断时间比例,降低其摄入率。结果揭示,熟悉的社群气味会促使觅食活动中的家族群成员个体,在监测环境风险时,将精力更多地用于观察和监听群内其他成员个体的行为及其发出的警报信息,以便在有效规避环境风险的同时减缓个体间因干扰性竞争对觅食活动所造成的不利影响;而陌生的社群气味会迫使成员个体,将精力由依赖群内其他成员个体的行为转向凭借自身直接警觉周围环境。

The effect of social group odors of family or non-family groups present in food patches on individual foraging behavior of family groups, and their intake rates is still unknown. To evaluate the effects of odors from family and non-family groups on the individual foraging behavior of family groups in reed voles(Microtus fortis), the foraging behavior and behavioral parameters of voles foraging in homogeneous food concentrated patches with bedding materials from family or non-family groups comprising fresh crabgrass(Digitaria sanguinalis) leaves were measured. The results showed that familiar social group odors significantly shortened the foraging decision time of individuals of family groups, the proportion of vigilance time of individuals of family groups for sniffing and upright scanning decreased, and the proportion of vigilance time for scanning, staring, and listening increased;therefore, the foraging interruption time of individuals of family groups was significantly reduced, and their intake rates increased significantly. However, unfamiliar social group odors dramatically increased the foraging decision time of individuals of family groups;the proportion of time for sniffing and scanning increased, and the proportion of time for upright scanning, staring, and listening in individuals of family groups dramatically decreased. Therefore, the foraging interruption time of individuals of family groups increased significantly, and their intake rates decreased. The results revealed that environments with familiar social group odors caused small herbivorous mammals to spend more energy on observing behavior and monitoring alarm signals of other members in family groups to avoid interfering competitions and risks. Meanwhile, in environments with unfamiliar social group odors, individuals of family groups adjusted their energy used for vigilance risks from depending on other members in family groups to self-reliance.