餌劑藥效與幾丁質合成抑制劑對入侵紅火蟻之實驗室評估

Evaluation of bait effectiveness and chitin synthesis inhibitors against Solenopsis invicta

劉錕(Kelvin Jordan Liu)

指導教授 ： 徐爾烈

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.02594

摘要

入侵紅火蟻 (Solenopsis invicta) 在其侵入地區造成了無以數計危害及經濟損失，在防治上，以緩效性的餌劑為最節約的防治方式，尤其是對於建立初期，不易被發現的蟻巢，相對於接觸性藥劑，餌劑的滅蟻效果顯得更為全面。但在目前全面用藥的防治思維下，以室內族群進行餌劑藥效試驗顯然是較為可行的方式。幾丁質合成抑制劑具有緩效性，對哺乳動物的毒性低，已被廣泛的應用在各類的昆蟲防治，然而卻一直沒有應用在螞蟻的防治上，本實驗以二福隆為主，進行室內評估。在27℃的室內條件下，每盒放入50隻工蟻 (不分體型)，餵食大豆油一週，取食量為16.3 ± 0.5 mg，相對於室內照明 (400 Lux)，在低光照的環境下 (4 Lux)，取食量降為10.3 ± 0.9 mg。以溶在大豆油內的0.05％愛美隆測試，取食量為11.57 ± 1.37 mg，若放入5-25隻的四齡幼蟲，取食量並沒有顯著差異，但若給予30、50、75隻工蟻各15隻幼蟲，各組間有明顯差異，則取食量取決於工蟻數量，與幼蟲數目關係不顯著。與50隻工蟻相較，放入至多25隻幼蟲，雖LT50有些微下降，無顯著差異；但放入5或15隻蛹，LT50顯著縮短。比較各組的取食量與LT50，兩者的相關係數R2=0.0394，相關性低。100、50與25隻工蟻，各0-20隻四齡幼蟲，測試芬普尼1.5 ppm餌劑成品藥效，有幼蟲的組別，LT50顯著低於無幼蟲的組別，不同幼蟲數之間的差異不顯著。工蟻無法直接取食大顆粒的食物，單獨存在時仍然會受到餌劑影響，而加入幼蟲可幫助消化固態食物，使藥劑易於傳遞，加快工蟻死亡的速度。
以溶在大豆油內的二福隆、三福隆與六福隆餵食工蟻，濃度為0.1 - 2.5％，在30天的實驗期間內，工蟻的死亡率皆在20％以下，與對照組無顯著差異，則對工蟻無直接毒性。以一完整的族群為單位，餵食0.5-2.5％之二福隆餌劑，在12週的實驗期間內，餵食1％二福隆之族群，其族群指數有顯著降低，其他兩組效果並不顯著；各組可觀察到幼蟲數量有減少，但工蟻數量則幾無變化，在10週後，各處理的族群皆開始恢復，在12週時，部分已恢復至實驗開始時的狀態。餵食四齡幼蟲1％二福隆，取不同天數進行切片，並無明顯的病變產生，且可順利化蛹並羽化，但實驗組之幼蟲在蛹便形成期的時間增長，而對照組之化蛹時間快於實驗組。綜合上述的實驗，幾丁質合成抑制劑對入侵紅火蟻的藥效並不佳。

關鍵字

入侵紅火蟻 ； 幾丁質合成抑制劑 ； 室內評估 ； 餌劑

並列摘要

Solenopsis invicta is definitely one of the most serious invaded species of the world. It has caused countless economic loss and public health risk. Unfortunately, it was found at Taiwan in 2003. The government purposes to eliminate S. invicta from Taiwan, and large amount of bait and contact insecticide has been applied in the field. In the meanwhile, some effort is still trying to screen out more effective bait to control S. invicta. However, ants can’t reproduce generations in laboratory. Under such condition, the simulative laboratory test using few laboratory populations is necessary to replace the field experiment and laboratory test with whole-colony. But bait effectiveness evaluation under laboratory condition is not constructed thoroughly.
50 workers (mix of minors and majors) is replaced in one box, and fed with soybean oil for one week under 27℃. The feeding rate is 16.3 ± 0.5 mg. Comparing to the room light condition (400 Lux), the feeding rate is 10.3 ± 0.9 mg and significantly lower with dim light (4 Lux). When tested with 0.05% hydramethylnon dissolved in soybean oil and consisted with 5 - 25 4th instar larvae more, the feeding rate is not significantly different at each larval number. But if 30, 50 or 75 workers set with 15 larvae, the feeding rate is positive to the worker number. Comparing to 50 workers alone, the LT50 is slightly shorter when set with up to 25 larvae, but no significantly difference; the LT50, however, is significantly shorter when set with 5 and 15 pupae. Above all, it is nearly not related between feeding rate and LT50, and the R2 is as low as 0.0394. Three sets of workers: 100, 50 and 25, with 0 – 20 larvae are fed with solid 0.00015% fipronil bait. The LT50 is significantly shorter in the treatment with larvae. The result shows that although adult workers can’t eat solid particle but still can been effected by bait. The existence of larvae can digest the solid food and transfer the chemical.
The chitin synthesis inhibitor is a kind of agro-chemical with slow action and is safe to mammal. It has been widely used against various insect pests, especially on termites, but is not used on ants. The death rate over 30days of workers is lower than 20% by feeding 0.1% - 2.5% diflubenzuron, triflumuron and hexaflumuron dissolved in soybean oil. No direct toxicity is observed on workers. As a single colony as an experimental unit, colonies are fed with 0.5 – 2.5% diflubenzuron bait. Only 1% diflubenzuron treatment shows significant reduction of population index over 12 weeks observation. Reduction of larvae is observed in most colonies, but not on workers. All treated colonies start to recover after the 10th week. 4th instar larvae fed with diflubenzuron do not reveal adverse effect on their digest system but shows delay in pupation. As the result, chitin synthesis inhibitors are not much effective to S. invicta.

並列關鍵字

Solenopsis invicta ； chitin synthesis inhibitor ； laboratory evaluation ； bait

參考文獻

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