| Among the most biodiverse lineages of hemipterans,the suborder Auchenorrhyncha comprises the four superfamilies Cicadoidea(cicadas),Cercopoidea(spittlebugs and froghoppers),Membracoidea(leafhoppers and treehoppers)and Fulgoroidea(planthoppers).The phylogeny of Auchenorrhyncha has long been controversial and alternative hypotheses have been proposed,based on the external morphological characters,molecular sequence data and behavior of meiotic chromosomes.However,very limited features were adopted from the internal anatomy.Herein,the present study focuses on the comparative morphology and ultrastructure of the digestive system,excretory system and reproductive system of 59 representatives in Auchenorrhyncha and 4 species in Heteroptera,with stereo microscope and transmission electron microscope.Their morphology,function and the significance of the phylogeny are discussed.The results are listed below:1.The salivary glands are paired structures,and consist of principal and accessory glands;the latter joins the former via an accessory salivary duct.The lobules of the principal gland in Cicadoidea are digital,whereas they are acinous in Membracoidea,Cercopoidea and Fulgoroidea.The shape and number of principal and accessory glands exhibit great differences.(1)In Cicadoidea,the accessory system consists of long thick accessory salivary tube,short thin accessory salivary duct and accessory gland comprised of several small acini.In Cercopoidea,though the accessory system is composed of 3 parts,the assessory salivary tube is very short;the accessory gland is oval-shaped.In Membracoidea,the accessory gland is oval,but the assessory salivary tube is absent in some species.The accesssory gland is oval in Delphacidae,Dictyophara sinica(Dictyopharidae)and Ricania speculum(Ricaniidae),but it is auriform in Lycorma delicatula(Fulgoridae),and pear-shaped in Euricania clara(Ricaniidae).(2)The accessory system of the salivary glands in Cercopoidea was observed for the first time;and the mistakes on the definition of accessory system in previous investigations were corrected.(3)The common salivary duct occurs in Cicadoidea,Fulgoroidea and some species in Membracoidea.(4)The anterior and posterior lobes of the principal gland in Heteroptera are lobed;the accessory gland is tubular.The number of lobes in Graphosoma rubrolineata and Cletus punctiger is more than that in Cnizocoris potanini and Eurydema dominulus.However the differentiation of accessory gland and corresponding duct is obvious in C.punctiger and C.potanini.2.The alimentary canal of Cicadomorpha comprises foregut(pharynx,esophagus),filter chamber,conical segment,midgut loop and hindgut(ileum and rectum).The morphology of the filter chamber and conical segment,the occurrence of peritoneal sheath,and the emerge site of the ileum exhibit great differences among different species:(1)In Cicadoidea,the filter chamber is rod-shaped and bent;the midgut loop divides into 3 parts;the ileum emerges from the apex of the filter chamber,except for Subpsaltria yangi,whose ileum emerges from the middle;the rectum is extremely dilated;a peritoneal sheath occurs in all the examined species of this superfamily.(2)In Cercopoidea,the filter chamber is rod-shaped,but not bent.The midgut loop divides into 3 to 4 parts;the ileum emerges from the bottom of the filter chamber;the rectum is slightly inflated.(3)In Membracoidea,the filter chamber is rounded;the midgut loop divides into 2 parts;the conical segment is well-developed;the ileum also emerges from the bottom;the rectum is greatly inflated.(4)In Fulgoroidea,an anterior diverticulum is located at the base of the esophagus;there is no filter chamber;the midgut is coiled;the ileum is greatly shortened;the rectum is remarkably dilated.The midgut of Delphacidae is highly coiled but not enveloped by a membranous sheath.In Fulgoridae,Ricaniidae and Dictyopharidae,the midgut is highly coiled and enveloped by a membranous sheath.(5)In Heteroptera,the alimentary canal is devoid of a filter chamber.The elongated midgut is not convoluted and is divided into 3 distinct zones:a greatly inflated anterior midgut,a tubular mid-midgut and a slightly inflated posterior midgut.The ileum is remarkably reduced,and the rectum is dilated.3.Species in Auchenorrhyncha(with the exception of Delphacidae that have 2 distally furcated Malpighian tubules)and Heteroptera have 4 tubules.Some variations in differentiation are as follows:(1)In Cicadoidea and Cercopoidea,each Malpighian tubule is differentiated into 5 parts;the intermediate duct and proximal segment are smooth,and the latter is thinner and longer than that of the former.The distal segment is the longest and the thickest one among the four segments,and nudulose in appearance.The terminal segment is wavy in appearance.(2)In Membracoidea,the intermediate duct is short and smooth,whereas the proximal segment is long and nodulose.The distal segment inflates to be glandular.The terminal segment is wavy in appearance.(3)In Fulgoroidea and Heteroptera,the each tubule is differentiated into 2 distinct zones:the smooth basal part,and the wavy or nodulose distal part.The distal part is the main part of the tubule,which lies freely in the hemolymph.(4)The extremities of the Malpighian tubules in Cicadoidea and Membracoidea are united in pairs.However,the tubules extremity of the Cicadoidea is enclosed in the peritoneal sheath and attach to the distal ileum;the terminal parts of the tubules in Membracoidea adhere to the surface of the rectum.(5)Each tubule in Cercopoidea terminates in a rod and adheres to the rectum surface.(6)Malpighian tubules in Delphacidae are furcated at the distal ends.4.The male reproductive system exhibits the following features:(1)Testis in Fulgoroidea,Membracidae and Heteroptera is covered by a sheath that is absent in Cicadoidea,Cercopoidea and Cicadellidae.(2)In Cicadoidea,each testis contains 46-300 oval or rod-shaped testicular follicles.The seminal vesicle is relatively absent.The vas deferens and paired accessory glands are long and well-developed.The vas efferens is furcated.An oval or spherical median ejaculatory duct opening into the aedeagus.(3)In Cercopoidea,the testis contains 10-34 oval or rod-shaped testicular follicles.The vas deferens is long and well-developed.The inflated seminal vesicle is rod-or gourd-shaped.(4)In Membracoidea(excepting for species of Typhlocybinae that possess 3 follicles),each testis has 5-29 oval or rod-shaped testicular follicles.The significantly inflated seminal vesicles are obpyriform-,oval-or gourd-shaped.The closely attached seminal vesicles are externally enveloped by a thin sheath.The vas deferens is short.(5)In Fulgoroidea,the testis possesses 3-6 chili-shaped testicular follicles.The seminal vesicles are factually formed by the spiral vas deferens enveloped by a membrane.5.The female reproductive system also exhibits some differences in the morphology of ovaries,lateral oviducts,median oviduct,spermatheca,accessory glands and collateral gland.(1)In Cicadoidea,the ovary is pie-shaped or spherical;each ovary consists of 115-342 ovarioles.The accessory gland emerges from the basal region of the lateral oviduct.Both the filamentous gland and speramathecal gland are well-developed.The spermatheca is spherical,and its joins the common oviduct via a long thick duct.(2)In Cercopoidea,the ovary is fusiform,and each ovary contains 10-32 ovarioles.Only Ptyelus aigripectus and Mesoptyelus fasciatus possess an accessory gland.The spermatheca is triangular,subuliform,spherical or gourd-shaped.The duct joining the spermatheca and common oviduct is greatly shortened.(3)In Membracoidea,the ovary is fusiform,and each ovary only consists of 3-13 ovarioles.Only some species have an accessory gland.The spermatheca exhibits differences among different species.(4)In Fulgoroidea,the fusiform ovary consists of 6-16 ovarioles.Fulgoridae(excepting for Dictyophara sinica)possesses a tufty accessory gland that is absent in the Delphacidae.The spermatheca is morphologically different in different species.The spermathecal gland is distally rod-shaped,bifurcated or multi-furcated.(5)In Reduvoidea,Pentatomoidea and Coreoidea,the ovary fusiform contains only 3-6 ovarioles.Cnizocoris potanini and Cletus punctiger are devoid of a spermatheca.No accessory gland is observed in Graphosoma rubrolineata and Eurydema dominulus.6.Phylogenetic analyses were based on the morphological data from 59 in-group exemplars in 54 genera representing all major lineages of Auchenorrhyncha,plus 4 out-group taxa.All combined analyses of these data support the monophyly of Cicadomorpha,and also support the monophyly of each of the following lineages:Cicadomorpha,Membracoidea,Cercopoidea and Cicadoidea.The analyses support the major relationships within Auchenorrhyncha as(Fulgoroidea(Membracoidea(Cicadoidea,Cercopoidea))).Internal relationships recovered within each superfamily shows evidence for:(1)the sister-group relationship between Cicadettinae and Tettigadinae;(2)the paraphyly of Aphrophoridae;(3)the monophyly of Cercopidae;and(4)the sister-group relationship between Membracidae and Iassinae. |
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