Biology of Ranatra sp. (Hemiptera: Nepidae) in Taiwan
研究生：吳金榮 Wu, Jun-Lrong
本論文研究斑節水螳螂Ranatra sp.之體型、發育時間、存活率、繁殖率、飢餓下的存活時間及捕食功能反應等生物學特性，以供天敵昆蟲生態及防治蚊子研究之參考。本研究之斑節水螳螂，在2000年於屏東地區採集，由陳萍萍博士鑑定疑為新發現種並加以命名為Ranatra incisa 但還未發表。首先，在恆溫箱15℃、20℃、25℃、30℃四種溫度下，以家蚊屬（Culex spp.）幼蟲飼育，卵期除15℃下，卵無法順利孵化外，在20℃下最長，達21.94±0.72天，在30℃下最短為7.0±0天，若蟲期，在20℃下，一齡若蟲無法進入二齡蟲期，在30℃下最短為25.67±0.69天，25℃下最長達31.77±0.69天。
30℃下成蟲食餌捕食量高於25℃，但同溫之下食餌捕食量則隨密度的增加而上升，在30℃下，成蟲在配對繁殖前，經24小時供給食餌後，在最低食餌密度為1隻時，雌蟲捕食率為94.7％，雄蟲為100％，在最高食餌密度為128隻時，雌蟲捕食率為56.4％，雄蟲為59.9％，呈第 II 型功能反應。
在30℃下，斑節水螳螂成蟲生殖前期平均每隻每日可捕食家蚊幼蟲（4-5齡期）74.3±15.8隻，相較於大肚魚（Gambusia affinis Baird and Givard）每日44.0隻、孔雀魚（Poecilia reticulate Peters）每日41.8隻高出甚多，顯示斑節水螳螂對蚊科之幼蟲防治潛力相當高。
The biology of Ranatra sp. (Hemiptera: Nepidae) including body size, development time, survival rate, fecundity, durable time of starvation, and predaceous functional response was investigated in this study. The individuals of R. incisa identified and published as a new species by Dr. Ping-Ping Chen were collected in Ping-tung area at 2000. The development of Ranatra sp. were studied at 15℃, 20℃, 25℃, and 30℃ respectively by feeding the larvae of Culex spp. as food. All eggs failed to hatch at 15℃, and the 1st instar could not developing into 2nd at 20℃ instar. The egg period is 21.94±0.72days at 20℃, and 7.00±0.00 days at 30℃. The time spands in nymphal stages totally were 25.67±0.69 days at 30℃, and 31.77±0.69 days at 25℃ respectively.
Starvation treatment after fed (60-70 larvae Culex spp. each day) for 10 days, the adult durable time of starvation was 30±5.0 days for females and 23±7.0 days for male at 30℃; 51.7±9.0 days for females and 47.7±11.0 days for males at 25℃, respectively.
The age-specific survival rate curves of males and females similar to each other. The mortality increased within 20 days after egg hatched. The adult survival time at 30℃ was longer than that at 25℃. At 30℃ the reproductive was happened (observed) earlier and the period longer than that at 25℃. However, their age-specific fecundity rate curves were similar. The prey consumption of adult at 30℃ was higher than that at 25℃. However, the prey consumption of adult repides increased along with the increasing prey density at the same temperature. The percentages of preys killed by unpaired adults were 100％ and 94.7％ at prey density 1 ind/cup; 59.9﹪and 56.4﹪at prey density 128 ind/cup, respectively. According to the analysis, it is recognized as type II function response.
One unpaired adults of Ranatra sp. could eat (4th or 5th instar larvae of Culex spp.) 74.3±15.8 ind/day. Compare to both Gambusia affinis (Baird and Givard)(44.0) and Poecilia reticulate (Peters)(41.8) and that Ranatra sp. has high potential for controling mosquito ADP. in the fielol.
Key words：Nepidae, Water walking stick, development, survival, fecundity, functional response.