溫度效應對大白斑蝶 (Idea leuconoe clara Butler) (Lepidoptera: Nymphalidae) 翅黑化面積之影響

蝴蝶翅的顏色表現可以透過環境的調節產生不同，透過20-羥基蛻皮激素 (20-Hydroxyecdysone, 20E) 將環境信號傳達給發育中的組織，造成不同的呈色結果。大白斑蝶除了原有的黑斑，原本白色的部位也可能有暗灰色的黑化。本試驗利用不同的生長溫度，於15、20、25、30、35、40℃飼養600隻個體，發現在35及40℃產生黑化個體。接著縮短極端溫度的時間，僅針對前蛹停滯期個體進行低溫10℃與高溫35、40℃的衝擊試驗，冷衝擊12 天後出現黑化59~69% 的個體；熱衝擊後的翅黑化更高達59~82%。生理激素方面，透過極端溫度飼養，蛹期發育時間越長，體內測得的20E濃度越高，於40℃最高溫度時20E濃度高達9260.6 ± 103.3 (pg/μl)，翅黑化比率最高。為了交互驗證20E與翅黑化的關聯性，於前蛹停滯期分別注入不同濃度的20E至不同的個體；結果濃度越高的處理，翅黑色斑紋卻逐漸變淡。綜上所述，高溫與低溫都會造成翅黑化，熱衝擊大面積黑化原本白色的翅區；冷衝擊則令原本的黑斑擴大。兩種不同黑化趨勢與其他文獻結果吻合。然而蛹期時能夠於高溫的處理檢測到較高濃度的20E，與直接注入不同濃度梯度的20E，高濃度的20E反而使翅斑紋變得更淡，推測與高濃度的20E能夠抑制幾個黑色素合成時上游基因表現有關；同時亦可知道高溫造成的調控機制亦不僅單一透過20E我們測試的路徑。本試驗得知極端溫度調節大白斑蝶翅黑色素的沈澱20E的確有參與，且蛹期前期這個特定時間的溫度對黑色素的沈澱有重要的影響。

關鍵字

大白斑蝶； 20E蛻皮激素；溫度影響；黑色素沉澱

並列摘要

Different wing color performance could be attribute to environmental factors, and 20-Hydroxyecdysone (20E), physioligcal signals to developing tissues. Idea leuconoe clara has large wingspan and black spots and the degree of coarseness and melanization of the wings are usually adopted for species identification. To test the effects of the development temperature on melanization of the wings of I. leuconoe, we reared 600 larvae under 6 constant temperatures 15-40°C and found 2 melanized adults under 35 and 40°C. We further conducted heat/cold-shock-treatments during their wandering stage before pupation. In response to the cold treatment, 2 melanized adults presented 59-69% of melanization of the wings area; on the other hand, 11 melanized adults presented 59-82% melanization under the heat treatment. In terms of hymoglobin detection survey, the higher the pupal development under extreme temperatures, the higher the 20E concentration in the body, in the 40°C test with the highest wing blackening rate, the concentration of 20E reached maximum as 9260.6 ± 103.3 (pg/μl). In order to confirm the relationship between 20E and the melanization of the wings area, different concentrations of 20E were injected during the wandering stage larva of I. leuconoe and keep in the same temperature. The black spots on the wings became lighter at higher 20E concentrations. In summary, high temperature and low temperature treatmentslead the wings to melanized, the heat shock will blacken the white area; however, the cold shock enlarged the black spots. The reverse results were revealed for the higher concentration of 20E were detected along with the higher temperatures treatments for wandering stage of I. leuconoe; on the other hand, direct injections of 20E titer under the same wandering stage treatments result in the lighter color on the wing spot. It is speculated that high concentration of 20E will inhibit the upstream melanin gene. This experiment confirmed that 20E played an important and complicated role in wing melanization of I. leuconoe clara.