燈光、顏色及溫度對登革熱病媒蚊之誘集能力及其熱感應基因TRPA1之表現

登革熱是臺灣最嚴重的蟲媒傳染病，目前仍無登革熱疫苗或治療性藥物，以病媒蚊防治作為主要防治手段。本研究致力於發展新型捕蚊工具，針對可吸引埃及斑蚊 (Aedes aegypti) 及白線斑蚊 (Ae. albopictus) 可能的物理性誘集因子，包含燈光、顏色及溫度，於實驗室進行評估測試，爾後探討蚊子熱感應基因之表現差異。實驗結果顯示，紫外光 (360 nm) 比藍光 (450 nm)、綠光 (510 nm)、紅光 (630 nm) 有更好的誘捕效果，埃及斑蚊 (n=50) 雌蟲誘捕率42.00±7.94%，雄蟲10.00±6.24%，白線斑蚊 (n=50) 雌蟲誘捕率46.33±3.78%，雄蟲15.67±4.04%。不同顏色色紙吸引埃及斑蚊雌蟲 (n=25) 的效果依序如下: 黑色 (24.53±2.02%) > 深藍色 (21.87±1.52%) > 紅色 (14.13±1.19%) > 綠色 (6.67±2.11%) > 淺藍色 (4.53±1.79%) > 黃色 (1.33±0.00%)；白線斑蚊雌蟲 (n=25) 則是: 紅色 (25.6±2.89%) > 黑色 (23.73±1.16%) > 深藍色 (20.53±0.73%) > 淺藍色 (6.4±1.16%) > 綠色 (5.6±1.11%) > 黃色 (2.4±2.89%)。結合黑色外殼的紫外光捕蚊燈誘捕效果高於單一誘引因子，埃及斑蚊雌蟲 (n=50) 誘捕率62.42±8.03%，白線斑蚊雌蟲 (n=50) 則是76.05±10.34%。容易吸引埃及斑蚊及白線斑蚊雌蟲的溫度範圍介於26-38°C，埃及斑蚊雌蟲 (n=25) 誘引率45.14±3.02%，白線斑蚊雌蟲 (n=25) 誘引率40.57±6.70%。色紙包覆的加熱板 (32°C) 誘引埃及斑蚊雌蟲(n=25) 效果如下：黑色 (70.67±4.62%) >深藍色 (65.33±8.33%) > 紅色 (50.67±9.24%) > 未包覆色紙 (45.33±10.07%) > 白色 (38.67±8.33%)，白線斑蚊 (n=25) 則是：黑色 (70.67±8.32%) > 深藍色 (72.00±6.92%) > 紅色(65.33±8.32%) > 未包覆色紙 (48.00±6.92%) > 白色 (41.22±6.11%)。在果蠅的研究中，TRPA會受環境溫度所調控，而在瘧蚊觸角上更發現TRPA1是熱感受性極高的通道蛋白，因此，我們除了探討熱因子的誘引效果，也想了解埃及斑蚊及白線斑蚊受到熱刺激後，身上是否也有類似的蛋白質表現。實驗中分離有受到熱誘引及沒有受到熱誘引的蚊子頭部萃取總RNA，以TRPA1基因片段進行定量分析，實驗結果顯示有受到熱刺激的蚊子，頭部TRPA1 基因的RNA表現含量是沒有被熱吸引的蚊子的1.48倍，白線斑蚊則是1.59倍。根據以上的實驗結果，我們得到特定的光波長、顏色及溫度對埃及斑蚊及白線斑蚊都具有相當程度的誘引性，以及發現其身上的TRPA1基因會受熱刺激而活化。未來，我們希望可以利用這些實驗成果，實際應用於登革熱病媒蚊防治工作，例如新型捕蚊工具開發，期待對於日行性的蚊蟲有更好的防治效果。

關鍵字

登革熱；病媒蚊防治；波長；顏色；溫度； TRPA1

並列摘要

Dengue fever is one of the most serious insect-borne infectious diseases in Taiwan. It has no vaccine or medicine for dengue now, so it should be relying on vector control. This study is aimed to develop physical strategies for trapping Aedes aegypti and Ae. albopictus by potential attractable factors, including light, color and temperature, as well as to analyze the performance of heat-activated channel gene expression. The results obtained from our laboratory experiment showed that ultraviolet light (360 nm) was more effective to attract diurnal Ae. mosquitoes than blue (450 nm), green (510 nm) and red (630 nm) light be. The attraction rate of female Ae. aegypti (n=50) and male (n=50) were 42.00±7.94% and 10.00±6.24%, and female Ae. albopictus (n=50) and male (n=50) were 46.33±3.78% and 15.67±4.04%. The preferences of female Ae. aegypti (n=25) to colors was shown in the following: black (24.53±2.02%) > deep blue (21.87±1.52%) > red (14.13±1.19%) > green (6.67±2.11%) > light blue (4.53±1.79%) > yellow (1.33±0.00%). Similarly, female Ae. albopictus to colors was: red (25.6±2.89%) > black (23.73±1.16%) > deep blue (20.53±0.73%) > light blue (6.4±1.16%) > green (5.6±1.11%) > yellow (2.4±2.89%). The combination of black color and ultraviolet for light trap led to higher attraction rate (62.42±8.03%) toward Ae.aegypti, and rate (76.05±10.34%) toward Ae. albopictus. Temperatures ranging from 26 ° C to 38 ° C could attract both Ae. aegypti and Ae. albopictus. The attraction rates of female Ae. aegypti (n=25) and Ae. albopictus (n=25) were 45.14±3.02% and 40.57±6.70%, respectively. The condition of color paper covered on heater at 32 °C brought higher attraction rate: black (70.67±4.62%) > deep blue (65.33±8.33%) > red (50.67±9.24%) > uncovered (45.33±10.07%) > white (38.67±8.33%). Similarly, female Ae. albopictus was：black (70.67±8.32%) > deep blue (72.00±6.92%) > red (65.33±8.32%) > uncovered (48.00±6.92%) > white (41.22±6.11%). In the studies on Drosophila, TRPA was affected by ambient temperature. In other studies, it was found that TRPA1 on Anopheles gambiae antennae acted as a kind of channels which would be excited by heat. Therefore, not only do we want to figure out attraction effect of heat on mosquitoes, but to understand levels of heat-induced gene expression in Ae. aegypti and Ae. albopictus. So this study separated the heads from mosquitoes, which were subsequently sorted into heat-attractable and non-attractable group. Then the total RNA was extracted from the heads followed by TRPA1 gene amplification using RT-PCR. The results showed that the level of TRPA1 expression in Ae. aegypti heads of attractable group were 1.48 times higher than non-attractable group, and those in heads of Ae. albopictus was 1.59 times as much as non-attractable group. Based on the these results, we got a specific wavelength, color and temperature that are able to efficiently attract Ae. aegypti and Ae. albopictus. And TRPA1 gene was found to be activated with heat excitement in Ae. aegypti. In the future work, based on our findings, we hope to develop a novel mosquito trap with more effective capacity for diurnal mosquitoes control, which could be expected to be applied in practical control of mosquitoes and prevention of dengue fever.

並列關鍵字

dengue ； vector control ； wavelength ； color ； temperature ； TRPA1

參考文獻

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燈光、顏色及溫度對登革熱病媒蚊之誘集能力及其熱感應基因TRPA1之表現

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