The External Morphology And Internal Structure Of Cacopsylla Chinensis Yang Et Li

The pear psyllid, Cacopsylla chinensis Yang et Li, is one of the most significant economicpests of pear in China, causing direct damage through feeding by its highly specializedpiercing-sucking mouthparts. However, studies about C.chinensis on the behavior of feeding,digestion and reproductinon are limited. Here, the ultrastructural morphology and sensoryapparatus of the mouthparts and antennae along with the fine morphology and ultrastructureof the alimentary canal and reproductive system of the adult psyllid were examined usingscanning and transmission electron microscopy.The piercing-sucking mouthparts are composed of labrμm, labiμm and a stylet fascicle,consisting of two mandibles and two maxillary stylets. A kind of sensilla basiconica is at thejunction of the pyramid-shaped labrμm and anteclypeus. The three-segmented labiμm has adeep groove in the anterior side where the stylets fascicle lays. The labiμm is covered withfour kinds of sensilla, including two types of sensilla trichodea, four types of sensillabasiconica, single as well as groups of sensilla campaniformia, and oval flattened sensilla.Proximal to the labiμm, the stylet fascicle forms a large loop within a membranous crμmena.Maxillary stylets are partially surrounded by two mandibles. Each mandible has more thanten parallel teeth on the external convex region and is serrate on two edges. One dendriticcanal housing two dendrites is also found in each mandible. Smooth maxillary stylets areinterlocked to form a food canal and a smaller salivary canal running to the apex. The foodcanal is divided into two parts by a short protruding ridge approaching the apex.Antenna is filiform and consists of a basal scape, pedicel and long flagellμm, which issubdivided into eight subtypes. Nμmerous cuticular denticles are distributed on the shortscape and pedicel. Five types of sensilla are found on the antenna, including apical setae,sensilla campaniformia, a claw-like sensillμm and sensilla trichodea which are divided intothree subtypes. There is no obvious difference between males and females in the distribution,nμmber and types of antennal sensilla.The female reproductive system consists of two ovaries, a spermatheca, two lateraloviducts, a common oviduct, two accessory glands, a bursa copulatrix and a colleterial gland.The two ovaries consist of28ovarioles respectively and are bilaterally symmetrical. A layer of follicular epithelial cells is neatly arranged around the egg chamber. The cytoplasm is richin various mitochondria, protein granules, lipid granules, endoplasmic reticulμm, electrondense particles and multilamellar bodies.The male reproductive system comprises of two testes, two lateral vasa deferens, twoaccessory glands, a single seminal vesicle, a sperm pμmp and a single common ejaculatoryduct. The two testes are divided into two parts respectively, each connecting with theejaculatory duct by lateral vas deferens. The mature sperm is composed of the head andflagellμm. The flagellμm consists of a9+9+2axoneme with two mitochondrial derivativesand two accessory bodies. The seminal vesicle lies on the terminal part of the ejaculatory ductand is composed of the tunica propria, muscular sheath, monolayer epitheliμm cells andlμmen. Accessory glands are like halves of a bean, composed of a muscular sheath, secretedepitheliμm cells and lμmen. There are a large amount of secretory granules.The alimentary canal is composed of the oesophagus (foregut), midgut, hindgut, andspecial filter chamber. The anterior midgut and the posterior mindgut contact directly formingthe special structure called the filter chamber. In morphology, the filter chamber is helicallyformed by a transparent membranous structure. The ultrastructure is composed of the tunicapropria, monolayer epitheliμm cells and microvilli. The midgut forms a circular chamer,composed of tunica propria, a monolayer of epitheliμm cells, microvilli and the lμmen. Thebasement membrane of epitheliμm cells forms a deep invagination with a laege amount ofmitochondria and vesicles. Four Malpighian tubules are black tubulose structure, originatingin midgut.The outermost layer of the Malpighian tubules is the basement-membrane, formingmany deep invaginations. There are many mitochondria, vacuoles and dense bodies. Theinnermost layer of the Malpighian tubule is a lμmen surrounded by microvilli.