两种果蝠对光叶桑(Morus macroura)果实的取食及种子传播

从2005年3月到2006年5月，在中国科学院西双版纳热带植物园沟谷雨林保护区内研究了两种果蝠——棕果蝠(Rousettus leschenaulti)和犬蝠(Cynopterus sphinx)取食光叶桑(Morus macroura) 果实的行为、夜栖息地分布、散布种子方式及范围等。借助月光对果蝠的行为进行直接观察，发现它们的取食活动一般在天黑20~40 min开始，取食高峰发生在22: 00~22: 30 和23:00~23:30之间，这两个取食高峰期平均取食次数(平均值±标准误)为(13.5±2.5)和(15.0±2.3)次，最低的取食频率发生在19: 00~19: 30和20: 30~21: 00之间，分别取食(0.2±0.2)和(0.7±0.5)次。果蝠很少在母树上取食成熟的果实，相反它们用嘴叼下果实并携带到夜栖息地去进食，通常这些夜栖息地是具有密闭树冠、密集枝条的树种。夜栖息地在母树周围的分布根据环境中适合它们栖息的树种和分布而决定，不同母树周围其夜栖息地分布具有非常大的变异与空间异质性。钝叶榕(Ficus curtipes)、铁力木(Mesua ferrea) 和糖胶树(Alstonia scholaris) 是果蝠最喜爱的夜栖息地。在同样的情况下，尽管需要飞行更远的距离，两种果蝠都比较喜欢寻找具有许多枝条和小枝并且有复杂树冠的树木作为夜栖息地。两种果蝠取食光叶桑果实时，一部分种子通过消化道消化后被排泄出来，另外的一部分伴随着咀嚼后的果渣被吐出来，通过这两种方式，散布了大量的种子，再加上在飞行中也有排泄的习性，它们传播的种子在空间上更广泛。

Fruit consumption and seed dispersal of Morus macroura by two frugivorous bats in Xishuangbanna, Southwest China

Feeding behavior on Morus macroura fruits by Rousettus leschenaulti and Cynopterus sphinx, their feeding roosts distribution around parent trees and seed dispersal patterns were studied in a protected forest at Xishuangbanna Tropical Botanical Garden from March 2005 to May 2006. Observations on the foraging behavior of the two frugivorous bats at M. macroura fruiting trees using moonlight after dark (about 19:00) around parent tree indicated that they seldom fed on the fruit at parent tree, but left with the fruits and flew to feeding roosts in other trees to consume them. Their foraging activity peaked two times at the first half night which were around 22:30 and 23:30 and the number of foraging bouts were 13.5±2.5 and 15.0±2.3 respectively. Lowest foraging rate happened between 19:00 to 19:30 and between 20:20 to 21:00 which were 0.2±0.2 and 0.7±0.5, respectively. Most of the fruits were eaten within 10 days when fruit ripening. Bats did not selected feeding roosts randomly, but according to the species and distribution of trees favored by bats around parent trees. So the distribution patterns of feeding roost were heterogenous around parent trees. Ficus curtipes, Mesua ferrea and Alstonia scholaris were favored feeding sites for bats. Although the bats could carry seeds to a variety of feeding sites available in the environment, they clearly exhibited a preference for specific trees based on their architecture. We suggested that a preferred feeding roost is often located under a horizontal bough with a dense drooping umbrella-like crown of leaves offering cover, such as M. ferrea and A. scholaris . Besides transporting seeds to feeding sites, bats can also disperse seeds through fecal deposition. The overall seed shadow is likely to be relatively extended and homogeneous.