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。     

Grooming in mandrills and the time frame of reciprocal partner choice

In this study, we examined the time frame of reciprocal partner choice in the grooming interactions of captive mandrills (Mandrillus sphinx) in order to test the hypothesis that the cognitive limitations of primates constrain the occurrence of reciprocation to short time intervals. In contrast to this hypothesis, mandrills groomed preferentially those individuals that groomed them more even when cases of immediate reciprocation were excluded from the analysis. These results show that mandrills were not limited to reciprocating grooming over short time intervals. It is proposed that a system of emotional bookkeeping may support the ability of primates to reciprocate over long time frames. Am. J. Primatol. 71:884–888, 2009. © 2009 Wiley‐Liss, Inc.     

Testing for genetic evidence of population expansion and contraction: an empirical analysis of microsatellite DNA variation using a hierarchical Bayesian model

The role of past climatic change in shaping the distributions of tropical rain forest vertebrates is central to long-standing hypotheses about the legacy of the Quaternary ice ages. One approach to testing such hypotheses is to use genetic data to infer the demographic history of codistributed species. Population genetic theory that relates the structure of allelic genealogies to historical changes in effective population size can be used to detect a past history of demographic expansion or contraction. The fruit bats Cynopterus sphinx and C. brachyotis (Chiroptera: Pteropodidae) exhibit markedly different distribution patterns across the Indomalayan region and therefore represent an exemplary species pair to use for such tests. The purpose of this study was to test alternative hypotheses about historical patterns of demographic expansion and contraction in C. sphinx and C. brachyotis using a coalescent-based analysis of microsatellite variation. Specifically, we used a hierarchical Bayesian model based on Markov chain Monte Carlo simulations to estimate the posterior distribution of genealogical and demographic parameters. The results revealed strong evidence for population contraction in both species. Evidence for a population contraction in C. brachyotis was expected on the basis of biogeographic considerations. However, similar evidence for population contraction in C. sphinx does not support the hypothesis that this species underwent a pronounced range expansion during the late Quaternary. Genetic evidence for population decline may reflect the consequences of habitat destruction on a more recent time scale.     

Delayed embryonic development in the Indian short-nosed fruit bat, Cynopterus sphinx

The unusual feature of the breeding cycle of Cynopterus sphinx at Varanasi is the significant variation in gestation length of the two successive pregnancies of the year. The aim of this study was to investigate whether the prolongation of the first pregnancy in C. sphinx is due to delayed embryonic development. The first (winter) pregnancy commences in late October and lasts until late March and has a gestation period of about 150 days. The second (summer) pregnancy commences in April and lasts until the end of July or early August with a gestation period of about 125 days. Changes in the size and weight of uterine cornua during the two successive pregnancies suggest retarded embryonic growth during November and December. Histological analysis during the period of retarded embryonic development in November and December showed a slow gastrulation process. The process of amniogenesis was particularly slow. When the embryos attained the early primitive streak stage, their developmental rate suddenly increased considerably. During the summer pregnancy, on the other hand, the process of gastrulation was much faster and proceeded quickly. A comparison of the pattern of embryonic development for 4 consecutive years consistently showed retarded or delayed embryonic development during November and December. The time of parturition and post-partum oestrus showed only a limited variation from 1 year to another. This suggests that delayed embryonic development in C. sphinx may function to synchronize parturition among females. The period of delayed embryonic development in this species clearly coincides with the period of fat deposition. The significance of this correlation warrants further investigation.     

西双版纳地区降雨和食物资源可获得程度对犬蝠分娩时机的影响

繁殖是动物权衡不同自然选择压力和自身生理限制的结果。蝙蝠的繁殖受气候(温度、光周期和降雨量)和食物资源等非生物因素影响。本文通过野外调查犬蝠食物资源、设网捕捉和标志重捕的方法研究西双版纳地区降雨、食物资源可获得程度对犬蝠分娩时机的影响。研究发现,随着3 - 8 月降雨量逐渐增加(19.82 -41.13 kg/ m2 ),犬蝠取食的植物种类呈明显的增加趋势(4 - 9 种)。幼蝠捕捉量与植物资源可获得程度呈显著正相关关系(r = 0. 94,P = 0.01)。西双版纳犬蝠虽然具有一年两次动情和分娩的能力,但是绝大多数个体一年只分娩一次,且集中于3 -5 月。犬蝠分娩时机的选择使得幼蝠飞行学习和捕食时间与食物资源可获得程度高峰期相吻合,有利于提高幼体的生存适合度。     

圈养山魈行为的初步观察

2001年1～9月,在成都动物园对人工饲养状态下14(8♀♀6♂♂)只山魈(Mandrillus sphinx)的行为时间分配进行了研究.用时间取样法记录每10分钟内目标取样法所见动物的各种行为及其频次,通过1806小时的研究表明,山魈主要的日行为是取食、休息、运动三种个体行为,它们分别占日活动时间的22.91%、33.79%、和33.14%;其次为梳理行为,占山魈日活动时间的4.09%;嬉戏行为仅发生在非成年个体间.山魈活动行为(除去休息以外的所有行为)的高峰出现在800～1000、1600～1800左右的两个时段.日活动时间集中在700～1900,但在1300～1400活动强度明显减弱,有一休息峰出现.     

地标对犬蝠空间记忆的影响

为了研究地标（landmarks）是否影响犬蝠（Cynopterus sphinx）的空间记忆,我们通过室内模拟试验研究犬蝠和地标在觅食过程中空间记忆形成的关系。实验组按照每天地标数分别为0、2、4、8、0的数目连续进行5天实验,对照组不设地标进行相同条件的实验。结果显示,两组犬蝠第一次取食所用的时间与实验天数之间极显著相关（Pearson Correlations: 实验组r=-0.593, P<0.01;对照组r=-0.581, P<0.01）;实验组取食成功率与实验天数之间无明显相关性（Pearson Correlations: r=0.177, P>0.05）;对照组取食成功率与实验天数之间显著相关（Pearson Correlations: r=0.445, P<0.05）。实验组与对照组犬蝠第一次取食的时间差异不显著（GLM: F_0.05,1=4.703, P>0.05）,两组间取食的成功率差异也不显著（GLM: F_0.05,1=0.849, P>0.05）。这些结果说明了随着时间增加,犬蝠对取食地的空间记忆逐渐形成,放置地标在犬蝠对取食地空间记忆形成的过程中无显著影响。     

Seed Dispersal of Morus macroura (Moraceae) by Two Frugivorous Bats in Xishuangbanna, SW China

The dispersal of Morus macroura seeds by two species of frugivorous bats ( Rousettus leschenaulti and Cynopterus sphinx ) was studied in a forest at Xishuangbanna Tropical Botanical Garden in Southwest China from March to May 2005. Feeding roosts were identified within 500 m around parent trees and the types and number of seed loads under each roost were recorded. We found feeding roost density decreased with increasing distance from the parent, but found no correlation between distance and seed deposition. The effect of bat digestion on seed germination was investigated, and we found that germination percentage of all treatments involving ingestion by bats was significantly lower than control seeds and some germination parameters of seeds from different treatments changed.     

犬蝠对不同浓度香蕉汁的选择

为了解犬蝠的嗅觉灵敏度,我们以6 只成年犬蝠对不同浓度的成熟香蕉汁和纯水对照的选择倾向和取食时间各进行了连续5 个夜晚的室内观察。香蕉汁的浓度分别为100% (120 g),50% (60 g 香蕉汁和60 g 纯水),25% (30 g 香蕉汁和90 g 纯水),12. 5% (15 g 香蕉汁和105 g 纯水);另取纯水(W)与熟烂的香蕉汁(OR)各120 g 作为对照。将以上食物和对照随机注入不同的容器内,观察犬蝠对不同浓度的香蕉汁、熟烂香蕉汁和纯水的选择。结果表明,犬蝠对纯成熟香蕉汁的选择性最强,取食次数和取食量均最高,而停留时间也最长;说明犬蝠具有分辨不同浓度的气味差异。我们推测犬蝠在野外觅食时可能优先取食成熟水果。