草地螟幼蟲和蛹的形態特征及雌雄鑒別方法

胡敏 程云霞 張蕾

摘要 草地螟雌、雄成蟲的形態特征及鑒別方法在室內研究及種群測報中已經廣泛應用，但幼蟲及蛹的形態特征及雌雄的鑒別方法目前尚沒有報道。本文借助超景深三維顯微系統，觀察不同齡期草地螟幼蟲的形態特征、5齡幼蟲性別特征以及雌、雄蛹的區別，以期為草地螟幼蟲和蛹的形態識別和性別鑒定提供科學分類依據。研究表明：1）初孵幼蟲體色為淡黃色，隨著齡期增大，體色逐漸加深，至末齡為灰黑色或黑色，3齡出現白斑和體側縱帶，5齡體背出現2條鮮黃色或黃白色背線;2）雄幼蟲第5腹節背管兩側有一對精巢，呈白色半透明橘瓣狀，3片精小囊隔膜將精巢分為4個小腔室，預蛹期2個精巢逐漸靠攏、融合并發生扭轉，蛹期完全融合成為一個不可剝離的圓球體，直至生命結束;雌幼蟲卵巢沒有明顯分化;3）雌蛹腹部8～10節分節不明顯，第8腹節中央的生殖孔和第9腹節的產卵孔連接組成一縱裂縫，裂縫兩側平坦，裂縫下端與排泄孔上端距離較遠，為（0.48±0.005）mm，腹部末端鈍圓;雄蛹腹部8～10節分節明顯，第8腹節無縱裂縫，第9腹節的生殖孔呈一縱裂縫與第10腹節相連，裂縫兩側各有一個半圓形瘤狀突起，裂縫下端與排泄孔上端距離較近，為（0.24±0.005）mm，腹部末端較尖。

關鍵詞 草地螟; 幼蟲; 蛹; 形態特征; 性別鑒定

中圖分類號： S433.4 ?文獻標識碼： A ?DOI： 10.16688/j.zwbh.2019450

Abstract Morphological characteristics and identification methods of Loxostege sticticalis male and female adults have been widely used in laboratory studies and population measurement， while the morphological characteristics and identification methods of larvae and pupae have not been reported yet. In this study， to provide scientific classification basis for the morphological identification of larvae and sex identification of pupae， super-high magnification lens zoom 3D microscope was used to observe the morphological and sexual characteristics of different instars of Loxostege sticticalis larvae， as well as the differences between male and female pupae. The results showed that 1st instar larvae body color is light yellow， as age increases， body color deepens gradually， at 5th instar， the color is grayish black or black. White spots and bands appears at 3rd instar， two bright yellow or yellowish-white lines appear on the back at 5th instar. There is a pair of white， kidney-shaped testicular on both sides of the dorsal tube of the 5th abdominal segment of male larvae， and 3 follicle lamina divide testis into 4 follicle. There is no obvious differentiation of ovary in female larvae. In female pupae，the two seams of the 8th to the 10th segments are not obvious， a longitudinal crack from gonopore in the middle of the 8th abdominal segment to oviposition hole in 9th abdominal segment. Both sides of the crack are flat. The distance from the margin of the oviposition hole to the anus is （0.48±0.005）mm. In male pupae， the two seams of the 8th to the 10th segments are obvious， there is no crack on the 8th abdominal segment but a longitudinal gonopore crack from the middle of 9th abdominal segment to the 10th abdominal segment. There are 2 visible lumps on both sides of the crack， respectively. The distance from the margin of the gonopore hole to the anus is （0.24±0.005）mm.

Key words Loxostege sticticalis; larvae; pupae; morphological character; sex identification

草地螟Loxostege sticticalis L.（鱗翅目：螟蛾科）是一種世界性的重大農業遷飛害蟲，具有間歇暴發、集中遷移為害的特點。其發生來勢兇猛、密度大、為害嚴重，幼蟲可為害48科259種植物，在我國廣泛分布于東北、華北和西北地區，并且曾對這些地區的農牧業生產造成過巨大的經濟損失[1-4]?！?br>