ALTERED FLOWER FRUIT CLUSTERS OF THE KITUL PALM USED AS ROOSTS BY THESHORT-NOSED FRUIT BAT, CYNOPTERUS SPHINX (CHIROPTERA, PTEROPODIDAE)

The short-nosed fruit bat (Cynopterus sphinx) creates bell-shaped cavi ties in flower/fruit clusters of the kitul palm (Caryota urens) by che wing and severing flower and fruit strings. These cavities (stem tents ) in which the bats roost are usually about one metre deep and 30 cm i n diameter. We observed groups of bats roosting in fully-formed stem t ents during the daytime, and the construction and subsequent occupancy of newly formed tent cavities. Stem tents are similar in principle to leaf tents except, instead of being formed when bats chew veins and t he surrounding tissues of leaves, stem tents are formed in C. urens wh en bats completely cut several of the central flower/fruit strings. Fl ower/fruit strings are mostly severed when they are in an immature sta ge, at times when they are thin and widely spaced. Once these strings thicken and become heavily-laden with mature fruits, bats cannot penet rate the cluster to sever them. Our observations suggest that a single male enters an immature flower or fruit cluster either from below or the sides and severs the central strings along the peduncle. In early phases of stem-tent construction, C. sphinx severs flower/fruit string s at a rate of about one or mio per day: and cluster alteration may co ntinue upwards to two months. Only one immature flower/fruit cluster o n a C. urens tree is available for alteration by bats at any given tim e. That this bat does not roost in the fruit/flower cluster during the day, when a tent is under construction, and the accumulation of chewe d flower and fruit strings beneath such a cluster in the morning, sugg ests that tent construction by C. sphinx is a night-time activity.