美洲蟑螂翅上感覺毛和感覺神經元的形態及其分佈情形

Abstract

本文證明美洲蟑螂的雙翅表面分佈著許多感覺毛。由掃瞄式電子顯微鏡觀察結果，我們發現美洲蟑螂翅膀上共有硬棘型、剛毛型、細毛型、短毛型、短錐型、長錐型及腔錘型等七種感覺毛。各感覺毛在翅上的分佈不盡相同，其中五種分佈在前翅的背面，三種分佈在前翅的腹面，六種分佈在後翅的背面，而在後翅腹面則幾乎沒有感覺毛。各感覺毛的數量也有差異，前翅背面以剛毛型最多，前翅腹面以短毛型較多，而後翅背面以長錐型最普遍。此外，利用甲基藍對翅膀染色，發現前、後翅內散佈著許多感覺神經元，依外型分為單極、雙極和多極等三類。由此可推測，美洲蟑螂的翅膀不單只有飛行的功能，可能還可藉由翅膀上的感覺毛來感受周遭環境的變化，並經由感覺神經元將訊息傳入中樞以調控行為。

There are many different types of sensillae distributed on the surface of wings in american cockroach. According to the research investigated using a scanning electron microscope, we have found seven types of sensillae on the dorsal and ventral surface of wings. These sensillae might be termed short-trichodeum, long-trichodeum, fine-trichodeum, chaeticum, short-basiconicum, long-basiconicum and coeloconicum. Each type of sensilla has a specific distribution pattern. There are five types of sensilla distributed on the dorsal surface and three types on the ventral surface of forewings. There are six types of sensillae distributed on the dorsal surface of hindwings, but we have found few or no sensilla on the ventral surface of hindwings. The quantity of long-trichodeum sensilla was more abundant than any other types on the dorsal surface of forewings, the chaeticum sensilla was more abundant on the ventral surface of forewings, whereas the long-basiconicum sensilla was the most abundant on the dorsal surface of hindwings. In addition, we used methylene blue to dye the wings and found that there were many sensory neurons distributed within fore- and hindwings. By their appearances, the sensory neurons could be divided into three types: monopolar, bipolar and multipolar neurons. We suggested that the wings of american cockroach might not only function in flying, but also could detect the changes of surrounding environment using sensillae. The messages collected form sensillae may deliver to central nervous system by the sensory neurons distributed within wings, and subsequently modulate behaviors.