狄氏大田鱉之保育生物學研究

Abstract

本研究旨在建立狄氏大田鱉 (Kirkaldyia deyrollei Vuillefroy) 基本生物學資料，建立該種保育生物學基礎資訊。在實驗室15℃、18℃、20℃、23℃、25℃、28℃、30℃、33℃、35℃定溫環境下飼養，結果顯示在 15℃及35℃下，若蟲無法順利完成若蟲期；在 18℃ ~ 33℃之間，若蟲的發育速率隨溫度上升而增加，以 18℃ (僅雄蟲) 下 119.5日最長，33℃下 33.26日最短；在室溫22℃~26℃下平均卵期為 7.1 ± 1.52 日；若蟲期平均發育零點為 8.04℃，有效積溫為 893.76 日度。除生活史資料外，也針對日照長度、水溫及越冬行為對於狄氏大田鱉的繁殖作探討。結果顯示繁殖行為主要和水溫高低有關，日照長短及越冬行為並非必要因子。 本研究除建立了狄氏大田鱉的大量飼養流程及繁殖環境的設置，對其行為提出詳細描述；並根據繁殖試驗的結果，對於前人研究提出狄氏大田鱉為一年一世代物種提出質疑。綜合本研究結果，亦進行此蟲之保育類評估，認為狄氏大田鱉應予列為台灣瀕臨絕種等級之保育類昆蟲。

The giant water bug, kirkaldyia deyrollei is a gradually endangered aquatic insect thought out the East Asia. They are known for its brood - caring behavior and the infanticide behavior of the female. Ecological studies in Japan and Korea showed they are univoltine species and their food habit mainly depend on frog populations in traditional paddy fields. In order to know the biology information of the giant water bug, we examined their life cycle under 15℃,18℃,20℃,23℃,25℃,28℃,30℃,33℃ and 35℃ in laboratory. The results showed nymphs development cannot successfully in 15℃ and 35℃. The average egg stage is 7.1 ± 1.52 days and nymph stage show that the development rate increases with rising temperature between 18℃ - 33℃. In 18℃(male only),20℃,23℃,25℃,28℃,30℃,33℃, the nymphal stage was 119.5, 67.29, 51.06, 42.58, 40.32, 35.79, 33.26 days respectively. The developmental threshold of the nymphal stage from 1st instar to 5th instar was 6.27, 6.27, 4.74, -1.66, 9.26, 6.27℃. The thermal summation was 911.17 DD. Experimental results show that the nymphal stage was 35.79 days in 30℃, we were wondering why the giant water bug is only one generation in a year. So we focus on the reproduction impact of light length, water temperature and overwintering behavior. We found that the reproduction behavior mainly depends on water temperature, light length and overwintering behavior is not necessary for the reproduction success of k. deyrollei. The criteria degree of conservation was also evaluated for the giant water bug, the result indicated the evaluated credit fitted to suggest as an endangered species of animals in Taiwan.