南蝠对鸟的捕食及其对昆虫的选择

2005年11月和2006年5、7、9月在贵州兴义研究了南蝠(Iaio)的食性。通过对南蝠粪便分析,发现7、9和11月份,鸟的残留羽毛在粪便中占很大比例,尤其是在11月份,鸟的羽毛占了食物组成的82%(体积百分比,下同),结果证实南蝠是一种食鸟蝙蝠。但在5月份的粪便中未发现鸟毛,而鞘翅目所占比例很大(85%);7和9月份,鸟的羽毛和鞘翅目残遗物所占的比例相当(7月份分别为44.6%和48.7%;9月份分别为51.1%和43.4%)。5、7、9、11月份南蝠取食鸟类的比例逐渐增加,而对鞘翅目的取食则逐渐减少。除取食鞘翅目外,南蝠还捕食鳞翅目、半翅目、直翅目和膜翅目等昆虫。对比捕食区内潜在的食物,发现南蝠对部分昆虫表现出明显的选择性,说明南蝠为选择性捕食者。

Bird Predation and Selection of Different Insects by Great Evening Bats (Ia io)

The diet of the great evening bat,Ia io,was studied in Guizhou province of China in November 2005 and May,July and September 2006.The diet was examined by faecal analysis.Bird feathers were found to comprise most of the great evening bats' faeces in July,September and November.This discovery demonstrates that the great evening bat is a bird-eating bat.In November,bird remains were found comprising 82%(by volume)of the bat faeces,but were not found in May.The food component in May mainly consisted of Coleoptera(85%).In July and September,the proportions of bird feathers and Coleoptera found in the bat faeces were similar(44.6% and 48.7% in July,51.1% and 43.4% in September,respectively).From May to November,the proportion of bird predation by the great evening bats gradually increased,and the proportion of Coleoptera eaten gradually decreased.Apart from Coleoptera,the great evening bats also preyed on other organisms,including Lepidoptera,Hemiptera,Orthoptera and Hymenoptera.Comparing the food components of bats by faecal analysis with the potential food availability measured in the foraging area,we suggest that the great evening bat is a selective predator.