Abstract The terrestrial firefly, Pyrocoelia analis Fabricius, is distributed at low elevations throughout Taiwan and occurs in a variety of habitats. This study compared differences in environmental factors of firefly habitats under different management regimes, and examined the influences of these environmental factors on fluctuations in its population. Four sampling sites in Pingtung County, southern Taiwan, were selected for this study. From May 2004 to August 2005, field surveys took place monthly. The PU site, at which no pesticides were used, is a weedy area on the roadside in a small village at Pingtung University of Science and Technology. The WG site is a managed betel palm (Areca catechu L.) plantation with wetter soil and a high coverage of weeds. The DP site is a managed betel palm plantation with a low coverage of weeds. The IT site is an abandoned betel palm plantation with drier soil and a high coverage of weeds. The results showed that the average air temperatures and relative humidities generally exhibited no significant differences among the sampling sites. The average firefly larval density (3.2 individuals (inds.)/m2) and male adults (7.4 counts/10 min) were highest at the PU site, followed by the WG site (1.7 inds./m2 and 6.2 counts/10 min, respectively). At these two sites, the average soil water content, ground plant coverage and height, and prey density were also consistently higher. At the DP site, where the vegetative cover was thinnest (28.1%), firefly larval density (0.5 inds./m2) and male adults (2.2 counts/10 min) were significantly lower. At the IT site, where the soil water content was lowest (16.3%) but weed coverage was high (up to 85%), almost no larvae were found. The pooled data from the four sampling sites showed that prey density was significantly higher at the sampling points where firefly larvae were found than it was at sites where larvae were not found. Male adults occurred from February to October, and larvae occurred from April to October. Prey were found throughout the entire year, but their density levels were lower during winter. There were high positive correlations (r = 0.50~0.80) among male adult abundances, larval densities, and prey densities at each sampling site. Air temperature and soil water content were also positively correlated with firefly and prey densities (r = 0.21~0.82), indicating a consistent seasonal fluctuation pattern between firefly populations and these environmental factors.
摘要 為探討台灣窗螢(Pyrocoelia analis Fabricius)棲地環境因子差異對其族群發展的可能影響。本研究約自2004年6月至2005年8月止，每月分別在屏東縣內埔鄉其雄成蟲常出現之四個樣區調查一次：屏科大樣區為不施農藥之水土保持邊坡草地；五溝樣區為地面植物覆蓋度高且較潮濕的檳榔園；東片樣區為地面植物體覆蓋度低的檳榔園；義亭樣區為地面植物覆蓋度高但較乾燥的無管理檳榔園。調查期間各月平均氣溫與相對濕度在樣區間多無顯著差異。在屏科大樣區，其平均幼蟲密度之3.2 individuals (inds.)/m2及雄成蟲出現數7.4 counts/10 min都最高；五溝樣區皆次之，分別為1.7 inds./m2及6.2 counts/10 min，這兩樣區之平均土壤含水率、地面植物覆蓋度與高度和食餌密度也都同時較高；東片樣區幼蟲密度0.5 inds./m2及雄成蟲出現數2.2 counts/10 min相對偏低，其地面植物體覆蓋度僅 28.1%；義亭樣區幾無發現幼蟲，地面植物覆蓋度達85.0%，但土壤含水率僅16.3%。合併四個樣區之資料分析：其幼蟲出現樣點之食餌密度為33.4 inds./m2，顯著高於無幼蟲出現樣點之13.7 inds./m2。其雄成蟲出現活動從2月到10月止，幼蟲則從5月到10月止，蝸牛等食餌全年都有發現，三者在5月至9月為較高活動期。雄成蟲出現數、幼蟲密度和食餌密度之季節變動消長，在各樣區具一致顯著正相關(r = 0.50~0.81)，而氣溫及土壤含水率也分別和這三者間具有正相關性(r = 0.21~0.82)，顯示其族群變動和棲地中氣溫、土壤含水率及食餌密度之季節變動型態趨於一致。
| Key words: Pyrocoelia analis, population fluctuation, betel palm orchard, larval habitat, environmental factor | | 關鍵詞: 台灣窗螢、族群變動、檳榔園、棲地、環境因子。 |
|