| Ectropis obliqua Prout and E.grisescens Warren belong in the subfamily Enno-minae of the Lepidoptera family Geometridae.They are the two main Lepidopteran pests in tea gardens,both of which are harmful to larvae eating tea leaves,occurring in multiple generations in 1 year,strong reproductive ability,larvae have gluttony,often causing serious economic losses to tea gardens.Due to the similar external morphology and feeding properties of E.obliqua and E.grisescens,it is often easily confused in production and research.At present,most of the research on these two species of Geometridae focuses on occurrence law,comprehensive prevention and control,physiology,etc.,while the morphological research is less,especially ultramorphology is rarely involved.In this study,the general morphology and mitochondrial COI gene were combined to classify and identify the specimens collected in the field,and the morphology and related sensillas of the eggs,larvae,pupae and adults of E.obliqua and E.grisescens were studied with the help of light microscopy and scanning electron microscope,which is expected to provide more morphological evidence for the classification and identification of the two related species,and provide a morphological basis for studying the occurrence law of tea garden pests and pest habits.The main findings are as follows:1.Egg ultramorphology: The eggs of E.obliqua and E.grisescens are oval in shape,but differ in the number of fertilisation holes and the number of leaflets that make up the ornament.The surface of the egg shell of 2 species of insects has polygonal chambers with irregular engravings;The fertilization hole area has 3 circles of petal-like ornaments,and the fertilization hole is located in the center of the flower ornament,concave inward.The E.obliqua has 2 fertilization holes,6-7 leaflets in the inner circle,9-10 leaflets in the secondary outer circle,and 6-8 leaflets in the outer circle;The E.grisescens has 4fertilization holes,7-9 leaflets in the inner ring,10-15 leaflets in the sub-outer ring,and9-10 leaflets in the outer circle.2.Larval ultramorphology: The type of antennae sensillas of E.obliqua and E.grisescens larvae is the same,only the number is different,and the type of mouthparts sensillas is different.Two species of insect larvae are distributed with three kinds of sensillas : sensilla styloconica,sensilla basiconica,and sensilla chaetica,and the sensilla chaetica is divided into two subtypes.There are 7 sensilla basiconica on the antennae of the larvae of the E.obliqua,and 6 sensilla basiconica on the antennae of the E.grisescens larvae.There are 6 pairs of sensilla chaetica on the labrum of the larvae of E.obliqua and E.grisescens,2 pairs of sensilla trichodea at the base of the mandible,8 distal incisor in the anterior molars,1 pair of sensilla trichodea at the base of the maxillary,tufted sensory cones at the end of the labial palpus,and 1 pair of sensilla trichodea on the labium.The difference is that there are 3 kinds of sensilla on the galea of E.obliqua: sensilla styloconica,sensilla basiconica,and sensilla chaetica,and galea of E.grisescens has 2kinds of sensilla: sensilla styloconica,and sensilla chaetica.3.The morphology of the pupae: The pupae of E.obliqua and E.grisescens are obtect pupae,dark brown,with 1 pair of spiraclesf on each side of the 2-9 abdominal segment,and 1 pair of terminal spines at the end of the 10 th abdominal segment,the base is connected.The male pupae have a short abdomen,9-10 segments of the ventral surface are healed,the genital pore is located in the 9th abdominal segment,and there is a semitumor-like protrusion on each side.The female pupae have an elongated abdomen,8-9abdominal segments are healed,and the genital pore of segment 8 is connected with the ovipositor hole of segment 9,forming 1 black fissure.The E.obliqua terminal spines are slender and long,and the E.grisescens terminal spines are thick and short.4.Adult morphology: The male internal genitalia of E.obliqua and E.grisescens are composed of testes,pre-and posterior seminal vesicles,vas deferens,ductus ejaculatorius duplex and ductus ejaculatorius simplex,and accessory gland.The former has less curvature of the ductus ejaculatorius duplex than the latter.The male external genitalia are mainly composed of harpes and phallus.The valvae of the E.grisescens gradually narrows from the base to the end,and the end of the E.obliqua cucullus is slightly enlarged.The angle between the flap of the E.grisescens and the holding abdomen is slightly larger than that of the E.obliqua.The juxta of the E.obliqua is fan-shaped,and the juxta of E.grisescens is oval.Compared to E.obliqua,the cornuti on the vesca of the E.grisescens are more pronounced.The female reproductive system of the E.obliqua and E.grisescens consists of the ovary,lateral oviduct,common oviduct,spermatheca,and accessory glands.The color of the ovaries is different,the former is pale cyan and the latter green.The ovaries usually have 8ovarian tubules,and some E.grisescens have 9 ovaries.The common oviduct connects the lateral oviduct on one side,in a "Y" shape,and the other end opens into the genital cavity.The spermatheca are slender,white or yellowish brown.The female external reproductive system consists of the corpus bursae and its appendages,seminal ducts,posteriors,and papillae anales.The corpus bursae is pouch-shaped,solid or translucent in milky white.The coccygeal capsule is located in the center of the cocaudal capsule,orange-red,and has 16 spines on the edge.The posteriors is slender and filamentous.The process is located at the end of the external genitalia,is a symmetrical left and right 2-lobed lobe,with long villi attached to the surface,and papillae anales and ovipository are located medially.Ectropis obliqua and E.grisescens adult antennae filamentous,mouthparts siphon type,antennae and upper mouthparts sensilla are more abundant.There were obvious differences in the type and subtype of antennae sensilla between the two types of Geometridae,and females and males of the same species also showed sexual dimorphic phenomena.A total of 7 types of sensillas were found on the antennae of the E.obliqua: B?hm bristles,sensilla trichodea,sensilla auricillica,sensilla basiconica,sensilla chaetica,sensilla styloconica,and sensilla squamiformia.In addition to the above 7 kinds of sensilla,sensilla coeloconica have also been found on the antennae of the E.grisescens.B?hm bristles mane is significantly different between females and males of the E.obliqua,and sensilla trichodea type I is endemic to females.Similarly,the distribution of B?hm bristles is different between females and males of the E.grisescens,the number of sensilla trichodea type I in females is greater than that of males,and the sensilla auricillica type III are only found in females,and sensilla coeloconica are endemic to males.There are three kinds of sensilla in the mouthparts of E.obliqua and E.grisescens:sensilla trichodea,sensilla basiconica and sensilla chaetica.The sensilla trichodea of E.obliqua is divided into 4 subtypes according to morphology,and E.grisescens is divided into 3 subtypes,and only the sensilla trichodea type IV is found in the middle of the antennae of the female of E.obliqua sensilla basiconica is divided into 3 subtypes: sensilla basiconica type I.,sensilla basiconica type II and sensilla basiconica type III,E.grisescens sensilla basiconica is divided into 4 subtypes: sensilla basiconica type I.,sensilla basiconica type II,sensilla basiconica type III and sensilla basiconica type V.Sensilla basiconica type II is distributed only the food canal of E.obliqua and E.grisescens.5.The content of A,T,G and C bases of COI fragments of E.obliqua was 30.2%,39.4%,14.5% and 15.9%,and the content of COI fragments A,T,G and C bases of E.grisescens was 30.2%,39.3%,14.7% and 15.7%,and the content of A+T was significantly higher than that of G+C,showing that the bias of A+T content was consistent with the content of mitochondrial DNA bases in typical insects.The interspecific heritage distance was 4.09%. |
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