荒漠昆虫天花吉丁虫的呼吸及体内水分损失特征

Respiration and water-loss characteristics in a desert insect Julodis variolaris Pallas(Coleoptera:Buprestidae)

为研究荒漠地区昆虫的呼吸及水分损失特征,以专性寄生在荒漠植物梭梭上的天花吉丁虫Julodis variolaris Pallas为对象,采用LI-6400光合分析仪测定在20℃下天花吉丁虫的呼吸量,并采用重量法测定了不同温度下其水分散失率。结果表明：天花吉丁虫呼吸为典型的不连续气体交换循环（discontinuous gas exchange cycle,DGC）的模式,DGC平均周期约需12.96min,爆发间期历时平均约占整个DGC历时的80%,CO2平均释放率为23.45μL/min。在25℃、30℃、35℃和40℃恒温条件下,单位时间内水分散失随温度升高而增加,10h内25℃和30℃之间的水分损失率无显著差异,但25℃和30℃与35℃、40℃之间的水分损失率具有显著性差异;10~24h内25℃、30℃、35℃之间的水分损失率具有显著性差异。荒漠昆虫天花吉丁虫在高温下的高脱水率和高死亡率说明,其在没有水分来源的情况下很难存活,而不连续呼吸模式是其适应高温干旱环境的对策之一。

To explore the respiration and water-loss of desert insects, respiration of a desert insect Julodis variolaris Pallas specially infesting on Haloxylon ammodendron at 20℃ was measured with LI-6400 Portable Photosynthesis System, and the rates of water-loss at different temperatures from 25 ℃ to 40℃ were determined by measuring weight loss. The results indicated that J. variolaris respired in the typically discontinuous gas exchange cycle （DGC）. The DGC duration was about 12.96 rain, of which the proportion of interburst duration was about 80%, and the CO2 release rate was 23.45 μL/min. With the temperature increasing, the rates of water-loss were augmented at the constant temperatures of 25℃, 30℃, 35℃ and 40℃. Within 10 h, there was no difference in water-loss rate between at 25℃ and at 30℃, but the rates of water-loss between at 25℃ and 30℃ and at 35℃ and 40℃ differed significantly; from 10 h to 24 h, the rates of water-loss were significant different between at 25℃, 30℃ and 35℃ . The high rates of water-loss and mortality of the desert insect J. variolaris at high temperature suggested that it could not survive without water source. The DGC mode of respiration is one of the strategies for its survival in high temperature and aridity.