溫度與寄主植物對美地綿粉介殼蟲族群介量之影響

Abstract

美地綿粉介殼蟲 (Phenacoccus madeirensis Green) 為近年來新入侵台灣之害蟲，已知其寄主範圍廣且繁殖力強，但國內外詳細之生態學資料十分缺乏。本實驗選定茄科之番茄 (Solanaceae: Lycopersicon esculentum)、豆科之綠豆 (Fabaceae: Phaseolus radiatus) 與菊科之咸豐草 (Asteraceae: Bidens pilosa) 為寄主植物，分別飼育於 15、20、25、28、30、32 與 35℃ 的定溫生長箱中，觀察記錄其各期發育、死亡率、成蟲壽命與繁殖力等生命表資料，並求其族群介量。美地綿粉介殼蟲在番茄上於 15℃ 及 35℃ 均無法完成生活史；在綠豆與咸豐草上於 15℃ 亦然。在 20 至 32℃ 範圍內，從卵到成蟲的平均發育時間均以 20℃ 下最長，依序在上述三種植物上，雄性分別為 78.39、58.43 及 61.39 日，雌性分別為 70.45、48.07 及 57.02 日。以 30℃ 下發育最快，雄性分別為 25.06、22.23 及 21.78 日，雌性分別為 24.77、18.42 及 19.49 日。從卵至成蟲全期之發育臨界低溫 (α) 依序為雄性 15.6、19.1 及 18.0℃，雌性為 13.8、16.6 及 17.4℃，有效積溫 (K) 則分別為雄性 399、425 及 400 日度，雌性為 477、411 及 404 日度。番茄上之累積死亡率於 15與35℃ 下均達 100％，28℃ 下死亡率最低，綠豆與咸豐草上之累積死亡率僅於 15℃ 下達 100％，25∼30℃ 時則較低。在三種植物上兩性之壽命均隨溫度升高而縮短，以 20℃ 最長，雄性約 5∼6 日，雌性約 26∼40 日，30℃ 下最短，雄性約 2∼3 日，雌性則約 12∼15 日。飼育於番茄上者於 28 與 32℃ 下，綠豆上者於 32℃ 下，咸豐草上者於 30 與 32℃ 均有空卵囊之出現。在番茄上之產卵量以 30℃ 下 67.8 粒最多，綠豆 28℃ 下 492.7 粒最多，在咸豐草上則以 25℃ 時 140.7 粒最多。最高的淨生殖率 (R0) 在番茄上為 30℃ 時之 33.9，綠豆上為 28℃ 時之 248.0，在咸豐草上則為 25℃ 時之 71.0。番茄與綠豆上之內在增殖率 (rm ) 與終極增殖率 (λ) 均以 30℃ 為最大，rm 值分別為 0.0282 與 0.0679，λ 值則為 1.0286 與 1.0702。在咸豐草上之 rm 值與 λ 值則以 25℃ 為最大，分別為 0.0229 與 1.0232。在番茄與綠豆上之族群倍增時間 (Dt) 均以 30℃ 下為最短，分別為 24.6 與 10.2 日，咸豐草上則以 25℃ 下 30.3 日為最短；平均世代時間 (T) 均隨溫度升高而縮短，30℃ 下有最短之 T，三種植物上分別為雄性 27.7、25.2 與 25.0 日，雌性 40.3、31.4 與 34.9 日。綜觀上述，美地綿粉介殼蟲生長繁殖的最適溫度約在 25∼30℃，而三種植物中以綠豆為最適合之寄主，但咸豐草可能是其終年生活的重要寄主。

Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae) is a newly invaded pest in Taiwan. Now it has been found in Yilan, Taipei, Taichung, Nantou, Changhua, Chiayi, Tainan and Pingtung. P. madeirensis has wide host range, including 57 species belonging to 19 families in Taiwan. Knowledge of the life cycle of P. madeirensis is essential to the success of its management program. The thesis investigated the effects of constant temperature (15, 20, 25, 28, 30, 32 and 35℃), with 70% RH and 12L: 12D photoperiod, on the development, survival, and reproduction of P. madeirensis on three representative host plants, namely tomato (Lycopersicon esculentum, Solanaceae), mung bean (Phaseolus radiatus, Fabaceae), and hairy beggarticks (Bidens pilosa, Asteraceae). P. madeirensis which reared on tomato at 15 and 35℃ and on mung bean and hairy beggarticks at 35℃ could not successfully complete the life cycle. The mealybug had the fastest development of all stages on three host plants at 30℃. The total duration of development of female mealybugs on tomato, mung bean and hairy beggarticks was about 25, 19 and 20 days, respectively. Males took about 3-7 days longer to develop than females. Developmental threshold (α,℃) from egg to adult on three host plants was 15.6, 19.1 and 18.0℃ for males, and 13.8, 16.6 and 17.4℃ for females, respectively. Adult males required a cumulated effective temperature (K, day-℃) of 399, 425 and 400 day-℃, respectively, while females 477, 411 and 404 day-℃, respectively. Cumulative mortality of the mealybug on tomato at 15 and 35℃ were 100%, on mung bean and hairy beggarticks at 15℃ was 100%, too. The lowest mortality on the three host plants were at 28℃, 25∼30℃ and 25∼30℃, respectively. The mean longevity of P. madeirensis decreased with increasing temperature. The highest fecundity was 67 eggs on tomato at 30℃, 493 eggs on mung bean at 28℃ and 141 eggs on hairy beggarticks at 25℃. Empty ovisac occurred at 28 and 32℃ on tomato, 32℃ on mung bean, and 30 and 32℃ on hairy beggarticks. The highest net reproductive rate (R0) on tomato was at 30℃, on mung bean at 28℃, and 25℃ on hairy beggarticks. The highest intrinsic rate of natural increase (rm ) was 0.0282, 0.0679 and 0.0229 respectively on tomato and mung bean at 30℃ and on hairy beggarticks at 25℃. Accordingly, the shortest doubling time (Dt) respectively on tomato and mung bean was 24.6 and 10.2 days at 30℃, and 30.3 days on hairy beggarticks at 25℃. The shortest mean generation time (T) was 28, 25 and 25 days at 30℃ on three plants, respectively. Thus, I concluded that the optimal range of temperature for P. madeirensis population growth was 25~30℃, and mung bean was the most suitable host plant among the three plants tested. But maybe hairy beggarticks was the most important host plant during the year.