Habitat Selection, Social Structure And The Use Of Olfaction In Foraging Behaviour Of Cynopterus Sphinx

Fruit bats live in tropical and subtropical regions. There are about 10 kinds of fruit bats distributed in China which belong to Pteropodidae, especially in South China (some controversial opinions exist). Cynopterus sphinx and Rousettus leschenaultia are two species of abundant and widely distributed pteropodid bats. The short-nosed fruit bat C. sphinx is a common species in Guangzhou. Habitat selection and social structure of C. sphinx were investigated. We have evaluated the ability of the short-nosed fruit bat to learn to associate the non-fruit olfactory cues with the availability of fruits. The experimental results imply that C. sphinx learn very fast to associate the availability of fruits with the presence of non-fruit odour like that of cedar wood oil, and hence can easily be trained using novel odour cues and fruit rewards.Habitat selection and social structure of C. sphinx in Guangzhou were investigated from September 2006 to November 2007 by direct roost censuses at their roost sites and capture study using mist netting. It was revealed that C. sphinx had a specific preference for roosting under the fronds of Livistona chinensis. Importantly, the habitat of C. sphinx overlapped heavily with the areas of human activity. A total of 44 roosting groups were captured. 42 of groups, accounting for 95% of the total, contained at least one male (the group of HG05 contained three female, which captured in part). And 27 of the groups, accounting for 61%, contained at least one female. Seven of groups contained a solitary male, two contained bachelor males, and another were polygynous or monogamous (only an adult in a tent).The short-nosed bat C. sphinx might use olfactory cues to locate and detected food, and be able to discriminate different food odour in a complex olfactory environment. We made the following experimental comparisons: true fruit and mimetic fruit; true fruit and soaked mimetic fruit. The results imply that C. sphinx is able to locate a food source by olfactory cues alone. Although the color and shape of mimetic fruit is similar to the true fruit, C. sphinx is able to find the true fruit by using olfaction. If the mimetic fruit was soaked with juice, C. sphinx could not respond to the true fruit and the soaked mimetic fruit. C. sphinx learns very fast to associate the availability of fruits with the presence of an odour in artificial environment and observation revealed that the ability getting by learning can maintain at least five days. As fruit ripens, a variety of the chemical and structural changes take place. Fruit-eating mammals are specifically sensitive to the odour of aliphatic alcohols that are products of microbial fermentation in fruit, and these may serve as indicators of fruit ripeness. We made the following experimental comparisons: 1) ethanol in water vs. water; 2) ethanol in fruit juice vs. fruit juice; 3) methanol in water vs. fruit juice; 4) methanol in fruit juice vs. fruit juice. We found that the presence the bats were not attracted by the smell of ethanol in water or in juice at concentrations similar to those in ripe fruit, compared to mixtures without ethanol. C. sphinx were deterred by the smell of ethanol at high concentrations greater than 1%. However, in contrast to methanol, fruit bats were neither attracted nor deterred by the smell of methanol in water or juice at any concentration.