台灣三種闊尾海蛇地理分佈及陸棲程度

Scoping Geographic Distribution and Terristrial Tendency with Thermal Tolerance and Preference of Three Sea Kraits (Laticaudinae) in Taiwan

張鈞睿(Chun-Jui Chang)

指導教授 ： 杜銘章

國立臺灣師範大學/理學院/生命科學研究所/碩士(2010年)

摘要

外溫動物需要仰賴外界環境調整體溫，因此環境溫度對動物的分佈及活動有相當重要的影響。台灣周遭的三種闊尾海蛇在東亞地區的分佈具有明顯的緯度差異，顯示三種闊尾海蛇對低溫可能有不同程度耐受能力，我預期低溫耐受能力可以反應三種闊尾海蛇分佈上的差異。此外，三種闊尾海蛇具有不同的陸棲程度，我預期這樣的差異會有三方面的影響：一、由於陸地溫度變異遠大於海洋，較陸棲的物種應該具有較廣的溫度耐受範圍。二、由於海洋環境不易調節體溫，我認為相較於常上陸的黃唇青斑海蛇與黑唇青斑海蛇，不離水的闊帶青斑海蛇的溫度調節行為應較不明顯。三、野外經驗得知黃唇青斑海蛇偏好日落前上岸，而黑唇青斑海蛇則偏好日落後上岸，我認為上岸時間的差異是由於黃唇青斑海蛇偏好較高的溫度所致。
為釐清以上疑問，我用溫度耐受能力 (CTM) 做為指標，測試三種闊尾海蛇的瞬間耐受能力是否與分佈北界的最低溫度有關，以及溫度耐受廣度是否與陸棲程度相關。溫度偏好實驗則用來評估三種闊尾海蛇是否因為陸棲程度不同而具有不同的溫度調節能力，以及黃唇青斑海蛇偏好日落前後上岸是否由於偏好較高的體溫，而黑唇青斑海蛇則偏好較低的體溫。
實驗結果顯示，溫度耐受的極限值 (CTMin與CTMax) 並不能直接反應三種闊尾海蛇的分佈。雖然闊尾海蛇類群內的分化不足以造成最高CTMax與CTMin的分化，闊尾海蛇的溫度耐受範圍仍較陸棲爬行動物狹窄。陸棲程度的差異同時反映在低溫馴養條件下的溫度耐受廣度，會深入內陸而且會在白天活動的黃唇青斑海蛇，由於較容易遭遇高溫，即使在低溫馴養環境下仍保有較高的高溫耐受能力，因此在低溫馴養下有較廣的耐受範圍。
不上岸的闊帶青斑海蛇具有較不明顯的溫度調節，三種闊尾海蛇的個體間平均體溫變異度以闊帶青斑海蛇 (SD=3.13)，顯著高於黃唇青斑海蛇 (0.91)以及黑唇青斑海蛇 (1.16) (Levene’s test, p < 0.05)。黃唇青斑海蛇的偏好溫度 (23.3± 0.1℃)，顯著高於黑唇青斑海蛇 (22.9± 0.1℃)。

關鍵字

闊尾海蛇 ； 溫度耐受 ； 溫度偏好

並列摘要

Temperature is critical to the distribution of ectotherms because they depend on the heat from the environment to regulate their body temperature. There are three species of sea kraits (Laticaudinae) in Taiwan. It showed significant differences among the three sea kraits in their latitudinal distribution, suggesting that they had different thermal tolerances. I predicted that the thermal tolerance of the three sea kraits may refledt their geographic distribution. On account of the different terrestrial tendency of the three species, three predictions were made: 1) Species with higher terrestrial tendency should have wider termal tolerance because the aerial temperature fluctuation is higher compared to the water temperature. 2) L. semifasciata, ther least proned to land, should have the poorest thermoregulation for being difficult to regulate its body temperature in sea water. 3) L. colubrina should prefer higher body temperature than L. laticauda due to the former preferred to land at dusk and the latter at night.
The result showed that critical thermal tolerance (CTMs) did not reflect their geographic distribution. Although there was no difference in thermal tolerance range among the three sea kraits, their thermal tolerance ranges were narrower than that of terrestrial reptiles. L. semifasciata was the worst thermoregulator among the three sea kraits. Its mean variance of preferred body temperature within species was the highest (SD=3.13) among the three sea kraits. L. colubrine did prefer higher body temperature (23.3± 0.1℃) than L. laticauda (22.9± 0.1℃)。

並列關鍵字

Laticaudinae ； CTM (Critical thermal tolerance) ； temperature preferance

參考文獻

1. Angilletta MJ (2001) Thermal and physiological constraints on energy assimilation in a widespread lizard (Sceloporus undulatus). Ecology 82: 3044- 3056.

2. Angilletta MJ, PH Niewiarowski and CA Navas (2002) The evolution of thermal physiology in ectotherms. Journal of thermal Biology. 27(4): 249- 268.

3. Ashmore GM and FJ Janzen (2003) Phenotypic variation in smooth soft shell turtles (Apalone mutica) from eggs incubated in constant versus fluctuating temperatures. Oecologia. 134: 182- 188

4. Avery RA (1971) Activity patterns, thermoregulation and food consumption in two sympatric lizard species (Podarcis muralis and P. sicula) from central Italy. Journal of Animal Ecology. 47: 143- 158

6. Ballinger RE, J Hawker and OJ Sexton (1969) The effect of photoperiod acclimation on the thermoregulation of the lizard Sceloporus undulates. Journal of Experimental Zoology. 171:43-47