衣蛾 (Phereoeca uterella) 生物學與造巢取材之偏好性分析

Abstract

“Clothes Moths (衣蛾) ”是指蕈蛾科中所含之數個不同的屬，例如Tineola、Phereoeca、Praeacedes、Sphecioses、Monopis等，而其中幾個種類會利用本身所吐的絲與收集的碎屑製作可攜式的巢，因此又稱之為Household casebearer或是Plaster bagworm。Phereoeca uterella是台灣居家環境中常見的衣蛾，本研究在台灣各地設點進行採集調查後發現台灣室內至少有兩種衣蛾，室外則有另一種，且均具有相似的造巢習性，但巢的外形則有所不同。因不同齡期的幼蟲口器大小不同，造巢所取用的材料顆粒大小也有所差異；幼蟲隨著成長而增大其巢，因此巢的外觀會有同心圓的現象發生，而此特性也記錄了環境的變化。本研究即對於衣蛾的造巢行為與取用材料做深入的探討；不同環境所提供的材料不同，幼蟲也能使用不同材料來造巢。而為了解此種類之生物學，本研究調查衣蛾所存在的環境溫溼度、照度、風速和海拔，對其外部形態、雄蟲外生殖器以及造巢的過程進行描述，並討論衣蛾的天敵。雖然在自然狀態，沙粒是最普遍被使用的材料，但若環境提供不同的原料，例如木屑、蟲糞等，牠們能隨機的使用並當成造巢的材料。在哺乳動物屍體上之昆蟲相消長記錄中，最後的分解階段出現的蛾類即為蕈蛾科 (Tineidae)，牠們能在乾燥的屍體上進行最後殘餘物的分解；將衣蛾造巢的生物特性與法醫昆蟲學相互連結，預期此造巢行為之特性可以提供連結犯罪現場的證據。

The name of “Clothes Moths” is generally referred to several different genera in the family Tineidae, such as Tineola, Phereoeca, Praeacedes and Sphecioses. Some of them can use their silk and the materials they collected to build a portable case, and usually called the household casebearers or plaster bagworms. Phereoeca uterella is the most common household clothes moth species in Taiwan. According to our general survey throughout Taiwan, we found that there are at least three clothes moth species. They have similar behavior of building the portable cases, but their case shapes are obviously different. Due to the fact that the different instar larvae have different size of mouthpart, the particle of the materials for building their cases are also different. Their cases will be enlarged when the larvae grow, and the morphology of their cases may show a pattern of concentric circles. We believe this phenomenon could also record the changes of the circumstances the larvae lived. In this study, we focus on the clothes moth’s case-making behaviors and the materials collected by the larvae from their surroundings. We found different environments could cause the larvae choosing different case-making materials. To analyze the preference of their case-making materials, randomly selected materials were supplied for the larvae. To understand the biology and case-making behavior of clothes moths, the related environmental parameters, such as humidity, illumination, wind velocity and elevation in the collecting sites were also recorded. In addition, their case shapes, male genitalia, case-building behavior and the nature enemies were also described for further references. Although sand is the most common material the clothes moth adopted for their casing, yet if different material offered in their living environments, such as saw dust or feces, they could also use them randomly as their case-making materials. So far, we know the larvae can use many different kinds of materials to build their cases. Previous studies have recorded some Tineidae larvae found on mammal’s corpses at the late dry decay stages. Thus, connecting the previously mentioned case-making behaviors of clothes moth to the forensic entomology may be a possible way to provide some evidences in further describing the environment of the crime scene.