保暖度與同類氣味對不同環境溫度下雄性台灣管鼻蝠棲所選擇的影響

Abstract

棲所是蝙蝠消化食物、休眠、交配、育幼、冬眠及社會互動的重要場所，並可幫助其避免受惡劣天氣及天敵的干擾。蝙蝠花費大部分的時間待在棲所內，因此如何選擇適當的棲所對於蝙蝠的活存至關重要。過去的研究結果顯示，臺北市立動物園週邊山區的台灣管鼻蝠（Murina puta）在不同環境溫度下的不同季節會選擇不同類型的棲所，推測與不同種類棲所的保暖度有關。然而，動物在選擇棲所時，除了外在物理條件之外，該棲所是否有其他個體使用後所留下的氣味也可能是重要的參考依據。本研究以臺北市立動物園周圍山區捕捉之台灣管鼻蝠進行操作實驗，探討不同環境溫度處理(18°C、22°C 及 26°C)下，實驗個體根據棲所保暖度與同類氣味殘留所進行之棲所選擇偏好是否會有所改變，並記錄每次實驗台灣管鼻蝠於棲所周圍的活動情形。結果顯示，在環境溫度為 18°C 時，受試個體偏向選擇保暖度較好和具有同類氣味殘留的棲所，環境溫度為 22°C 與 26°C 時則對兩種棲所無顯著偏好。保暖度與同類氣味兩因子交互作用實驗中，台灣管鼻蝠在棲所選擇上有優先考量不同類型因子的趨勢：環境溫度為 18°C 時優先考量保暖度偏好；環境溫度為 26°C 時氣味偏好的影響則較為明顯。此外，本研究亦發現台灣管鼻蝠會於最後選擇之棲所周圍累計展現較多與較長時間的行為，其中又以爬入行為最能反映出個體的選擇偏好。

Bats spend most of their lives in their roosts where they can digest food, sleep, mate, rear young, hibernate, and interact with their roost mates. Roosts can also provide protection against adverse weather and predators. Thus, choosing a proper roost is crucial for bats’ survival. According to past research, Taiwan tube-nosed bats (Murina puta) found in the mountainous area around Taipei Zoo select different roost types under different ambient temperatures during different seasons, which is thought to be related to the insulation of the roosts. However, it has also been found that many animals choose their roosts solely based on odor instead of other measurable variables. In my research, I tested whether M. puta shift their roost preferences based on the insulation of the roosts and the presence of conspecific odors in the roost under three different ambient temperatures (18°C, 22°C, 26°C). My results show that at 18°C, but not 22°C and 26°C, M. puta tend to choose either the roost that insulate better or with conspecific odors when the two factors were tested separately. M. puta tend to consider insulation preference over odor preference at 18°C, while the tendency is reversed at 26°C. In addition, M. puta spend more time and exhibit more behaviors around the roosts they eventually selected.