東方果實蠅乃力松抗性與感性品系之生活史特徵比較

Comparison of Life History Traits between the Naled-resistant and -susceptible Lines of the Oriental Fruit Fly (Bactrocera dorsalis)

方棋羣(Chi-Chun Fang)

指導教授 ： 許如君 ； 吳文哲

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.01843

摘要

東方果實蠅 (Bactrocera dorsalis (Hendel)) 為果樹的重要害蟲，由於其環境適應力較強且具高生殖潛能，防治也較困難。台灣已因長期施用有機磷類殺蟲劑，導致果實蠅產生抗藥性。為找出抗藥性族群與非抗藥性族群間之生活史差異以增加防治工作的效率，本研究分為三個部分：首先，比較 20、25 及 30℃ 等溫度下乃力松抗性蟲及感性蟲兩族群孵化率、卵至蛹期各齡期發育日數、成蟲壽命、成蟲產卵量及族群介量，探討室內篩選之乃力松抗性蟲是否產生適應度代價 (fitness cost)。此外，比較田間東方果實蠅有機磷抗性基因頻度 (resistant allele frequency) 是否與溫度有關以驗證室內試驗之結果。最後利用矩陣模型 (Matrix model) 所得知族群介量預測不同階段 (stage) 的防治率對該族群的影響，以供管理之參考。第一部分結果顯示，除感性品系於 25℃下之卵期發育日數最短外，抗性與感性品系自卵到蛹期所需發育日數皆隨溫度上升而縮短，且兩品系各溫度下之孵化率並無顯著差異；感性品系除卵期於 30℃ 下與抗性品系無顯著差異，其餘卵期、幼蟲期及蛹期日數於各溫度下皆顯著短於抗性品系；感性品系成蟲壽命於 20℃ 顯著短於抗性品系，但於 30℃ 則顯著較長；兩品系皆於 25℃ 有最大成蟲產卵量，除於 20℃ 下兩者無顯著差異，於其它溫度，感性品系之成蟲產卵量皆顯著大於抗性品系。此外，在 3 種定溫下，兩品系族群介量之平均世代時間 (T)、內在增殖率 (rm)、期限增殖率 (λ) 及族群倍增時間 (Doubling time, DT) 皆隨溫度上升而縮短。感性品系之淨生殖率 (R0) 在25℃ 有最大值 362.97，最小值則是在 20℃ 的229.86，而抗性品系之淨生殖率 (R0) 在25℃ 有最大值 234.57，最小值則是在 30℃ 的 189.90；感性品系之平均世代時間 (T) 分別於 30 與20℃ 有最小值 46.55日與最大值 58.06日，而抗性品系之平均世代時間 (T) 也於 30 與20℃ 分別有最小值 41.66日與最大值 62.01日；感性品系之內在增殖率 (rm) 分別於 30 與20℃ 有最大值 0.123 與最小值 0.093，而抗性品系之內在增殖率 (rm) 於 30 與20℃ 有最大值 0.126 與最小值 0.087；感性品系之族群倍增時間 (DT) 分別於 20 與30℃ 有最大值 7.40 日 與最小值 5.64 日，而抗性品系之族群倍增時間 (DT) 分別於 20 與 30℃ 有最大值 7.93 日 與最小值 5.50 日。整合上述結果求得之相對適應度 (relative fitness) 可得知，人為篩選之抗性族群確實於25 與 30℃產生了適應度代價。野外調查方面，以乙醯膽鹼酯酶基因點突變偵測結果顯示，野外果實蠅抗性基因頻度於 19.4℃ 下為69%，較 28.8℃ 之 43% 為高，表示於相同密度下抗性蟲數量於低溫時較感性蟲為多，推估低溫環境較利於抗性族群的維持。於矩陣模型的預測計算中，果實蠅的生活史分成 5 個階段：卵、幼蟲、蛹、未性成熟成蟲 (sexually immature adult, SIA) 與性成熟成蟲 (sexually mature adult, SMA) 進行預測分析。結果顯示，若改變每日存活率，抗性品系於 20℃ 下影響期限增殖率 (λ) 最大的階段為 SIA 與 SMA，而在25 與 30℃ 下對族群造成最大影響的階段為SIA；感性品系於 20℃ 下影響期限增殖率 (λ) 最大的階段為蛹期，而在25 與 30℃ 下對族群造成最大影響的階段為SIA。此外，若模擬各階段延長對族群造成影響的程度來看，延長兩品系的卵期對族群成長的影響最大，而延長兩品系的 SMA 對族群成長的影響是最小的。整合上述，於不同溫度下，防治抗性族群的SIA可達到最佳防治效果。建議未來防治方法可配合該區域果實蠅抗性頻度與平均氣溫，針對未性成熟成蟲階段進行防治，以達成較佳防治效果。

關鍵字

東方果實蠅 ； 生命表 ； 乃力松 ； 適應度代價 ； 抗性基因頻度 ； 矩陣模型

並列摘要

The oriental fruit fly (Bactrocera dorsalis (Hendel)) is an important economic pest for tropical fruits in the world. In recent years, fruit flies (Bactrocera spp.) resistances to organophosphate insecticides (OPs) in the field have been reported in Taiwan. Generally, the resistant populations are hypothesized to have fitness costs as compared to the normal group, because they have the ability to generate resistance. There are three parts in this research for finding the differences of the life history traits between the resistant line and susceptible line to make the pest controls more efficient. Firstly, we investigate the fitness performance by comparing life-history traits (life table) between the naled-resistant and -susceptible lines of oriental fruit flies. We mainly compare the hatchability, the duration of egg, larval, and pupal stages as well as adult longevity and fecundity of the two lines under three constant temperatures (20, 25, and 30°C). We also compared the relationship between the OPs resistant allele frequency and temperature conditions in the field for proving the situation of adult longevity between the two lines in the laboratory. As to the application of the life table results into pest management of the oriental fruit fly, the third part of this study is predicting the population parameters by the matrix model and estimating the influences of different controlling rates to the fruit fly populations. The first part of the results showed no significant differences of egg hatching rate between the two lines. However, the susceptible line significantly possesses shorter developmental time of egg, larval, and pupal stage at every temperature than those in the resistant line, except the egg stage at 30°C, where there was no significant difference. The adult longevity of the resistant line significantly outlives susceptible populations under 20°C, but is significantly shorter than the susceptible line at 30°C. The highest fecundity values occur at 25°C in both lines though there are no significant differences between the two lines at 20°C. However, the fecundity of the susceptible line at 25 and 30°C are significantly higher than the resistant line. The values of mean generation time (T), intrinsic rate (rm), finite rate of increase (λ), and the doubling time (DT) are increased from 20 to 30°C. The highest and lowest values of the net reproductive rate (R0) in the susceptible line are 362.97 and 229.86 at 25 and 20°C, respectively. However, the highest and lowest values of the net reproductive rate (R0) in the resistant line are 234.57 and 189.90 at 25 and 30°C, respectively. As to the mean generation time (T) in the susceptible line, the lowest and highest values are 46.55 d and 58.06 d at 30 and 20°C, respectively. In contrast, the resistant line also has the lowest and highest values at 30 and 20°C, which are 41.66 d and 62.01 d, respectively. On the aspect of the intrinsic rate (rm), the highest and lowest values are 0.123 and 0.093 in the susceptible line, respectively; the highest and lowest values of the intrinsic rate (rm) are 0.126 and 0.087 at 30 and 20°C, respectively. The highest and lowest values of the doubling time (DT) in the susceptible line are 7.40 d and 5.64 d at 20 and 30°C, respectively, and the highest and lowest values of the doubling time (DT) in the resistant line are 7.93 d and 5.50 d at 20 and 30°C, respectively. Results of the relative fitness costs from this study are generally consistent with the hypothesis of fitness cost on the resistant line at 25 and 30°C. On the concept of field investigation, the results of detecting the gene point mutation of acetylcholinesterase show that the resistant allele frequency at July, 2008 and March, 2009 are 69% and 43%, respectively, indicating that the amount of the resistant population was higher than the susceptible population when the temperature was lower. Hence, the differences of the adult longevity between both lines at 20 and 30°C can be explained. In the estimation by the matrix model, the life cycle of the oriental fruit fly was divided into 5 stages, including the egg, larval, pupal, sexually immature adult (SIA), and sexually mature adult (SMA) stage, for evaluating the eigenvector. The estimations of the λ change with daily survival probability which show that the eigenvector of the resistant line is 20°C at SIA and SMA stages and the eigenvector of the susceptible line are 25 and 30°C at the SIA stage. In contrast, the same estimations of the eigenvectors of the susceptible line at 20, 25, and 30°C are pupal stage, SIA, and SIA stages, respectively. Finally, the estimations of the λ by changing in stage duration show that if the egg duration is elongated, the λ will decrease sharply in both lines. However, elongating the SMA little influences the population growth of both lines. It suggests that we can do the pest control based on the resistant allele frequencies and the temperature conditions in certains area at the SIA stage.

並列關鍵字

Bactrocera dorsalis ； life table ； naled ； fitness cost ； resistant allele frequency ； matrix model

參考文獻

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