菱角新害虫林间环足摇蚊的形态及生物学特性初步研究

A preliminary study on the morphological and biological characteristics of Cricotopus sylvestris (Fabricius)(Diptera:Chironomidae),a new pest of water caltrop

为明确广东湛江菱角上一种新害虫的种类及其形态、生物学特性,开展了野外调查、采集,室内饲养、观察,结合DNA条形码技术进行了种类鉴定。研究发现:该虫以幼虫聚集在菱角植株的茎部、叶柄、叶背面啃食为害,一生经历卵、幼虫、蛹、成虫四个时期。卵长椭圆形,数百粒卵包裹于卵囊中呈带状或螺旋状,卵期4.333 3 d;幼虫蠕虫状,体色近透明,消化道清晰可见,幼虫期9.580 6 d;蛹为裸蛹,蛹期3.190 3 d;雌、雄成虫的体长分别为0.256 4、0.348 0 cm,寿命分别为2.193 5、1.580 6 d。雌、雄成虫均呈黄色,翅面无斑纹,足的节间呈深色,身体躯干具深色斑纹,胸部背面具3条深色纵纹。该虫具有幼体生殖及孤雌生殖习性,单头幼体产卵319.2粒,显著高于单雌产卵量。经COⅠ序列比对及系统发育分析,明确该虫为林间环足摇蚊Cricotopus sylvestris (Fabricius)。

In order to clarify the species of a new pest and its morphological and biological characteristics on water caltrop in Zhanjiang,Guangdong province,we conducted field investigations and collections,as well as indoor rearing and observations.The species was identified by DNA barcoding technology.The results showed that the larvae of this pest gathered in the stalk,petiole,and leaf back of the water caltrop plant.The pest exhibited four distinct life stages:egg,larva,pupa,and adult.The eggs were observed to be enlonged ovoid in shape,and hundreds of eggs were found to be encased in oocysts in a ribbon-or spiral-like shape.The duration of the egg stage was 4.333 3 days.The larvae were worm-like in appearance,with a nearly transparent body color,and the digestive tract was clearly visible.The duration of the larval stage was 9.580 6 days.Pupae were exarate,with a duration of 3.190 3 days.The mean body length and life span of female and male adults were 0.256 4 cm and 2.193 5 days,and 0.348 0 cm and 1.580 6 days,respectively.The body color of the male and female adults was yellow,with no markings on the wing surface.Three black stripes were observed on the dorsum of the thorax,with some black stripes on the abdomen as well.This pest exhibited characteristics of larval reproduction and parthenogenesis.The amount of eggs laid by a single larva was 319.2,significantly higher than that laid by a single female.Phylogenetic analysis and sequence alignment of the COⅠ gene revealed that the pest was identified as Cricotopus sylvestris(Fabricius).