t:p~~A 16: 35-40(1996) Chinese J. Entomol. 16: 35-40(1996)

Antenna! Sensory Plaque Organs of (Homoptera: Fulgoroidea)

Chiou-Ling Cheng* and Chung-Tu Yang Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan, R.O.C.

ABSTRACT

' The antennal sensory plaque organs of 15 species of Tettigometridae were examined. Four types of sensory plaque organs were observed: type I , the cuticular ring plain, .the porous plate outwardly expanded marginally; type II , the cuticular ring elevated, the porous plate not expanded, protruding from dorsal margin of ring; type ill, the cuticular ring elevated, smooth, the porous plate distinctly separated from ring; and type IV, same as in type ill but elevated cuticular ring irregularly ridged. The evolutionary trend of this organ based on the developmental data is suggested to be type I -+type II -+type ID-type IV. Key words: Tettigometridae, antennae, sensory plaque organs.

Introduction family as having a flat plate surface and an unsculptured edge. This paper is one The porous sensory plaque organs are of a serial of papers on the sensory d:lstributed on antennal pedicels of the plaque organs in which we examine every Fulgoroidea (Bourgoin, 1985; Asche, species available throughout the entire 1987). Fulgoroidea is the only group Fulgoroidea. Four types of sensory plaque bearing sensory plaque organs in Auche­ organs have been detected, and they are norrhyncha. Tettigometridae is a small useful for phylogenetic analysis. family of Fulgoroidea, containing 12 gen­ era and 70 species (O'Brien and Wilson, Materials and Methods 1985), and is considered to possess the most primitive character state of the Dried specimens of 15 species of Fulgoroidea (Emeljanov, 1990; Yang and several genera of Tettigometridae were Hsieh, 1994). examined in this study: in Tettigometri­ Extensive structural variations occur nae are Brachyceps laeta (Her­ in the antennal sensory plaque organs of rich-Schaffer ), Micrometrina baranii (Sig­ different families in Fulgoroidea (Mar­ noret), Tettigometra costulata Fieber, Te­ shali and Lewis, 1971; Bourgoin . and ttigome_tra hexaspina Kolenati, Tettigome­ Deiss, 1994). The sensory plaque organs tra hispanica Fieber, Tettigometra impress­ in Tettigometridae were first studied by ifrons Mulsant et Rey, Tettigometra ob­ Bourgoin ( 1985), and this author reported liqua Panzer, Tettigometra picta Fieber, the characteristic plaque organ of the Tettigometra sulphurea Mulsant et Rey,

*Correspondence I reprint request address Antenna] plaque organs of Tettigometridae 35 Tettigometra eremi Lindl., and Tettigome­ gin of porous plate somewhat incurved tra sp.; in Egropinae is Egropa bengale­ but indistinct. nsis Distant; and in Hildinae are Hilda Type ill: The cuticular ring elevated, undata Walker, Hilda patruelis Stal, and smooth; the porous plate distinctly sep­ Euphyonarthex phyllostoma Schmidt. arated from the ring (Figs.8, 13). The antennae were amputated and The cuticular ring elevated, surface treated in a hot solution of 10 % KOH for smooth. Margin of porous plate slightly 25 min, then dissected and pressed in expanded outwardly, distinctly incurved. glycerin in order to check the number of Space between porous plate and cuticular sensory plaque organs through a light ring deeply grooved, with a few fine microscope. For scanning electron micro­ ridges connecting them. scopic observation, the antennae were Type IV: Same as in type III except taken from the KOH solution and rinsed elevated cuticular ring irregular, oblique­ in distilled water. Then the antennae ly ridged (Figs.10, 14). were fixed at 4 °C for 2 h in phos­ In addition to these descriptions, the phate-buffered 0.1 M glutaraldehyde, de­ types and total number of sensory plaque hydrated through 50 %, 70 %, 80 %, 90 %, organs in each pedicel of 15 species are 95 % and 100 % alcohol for 20-30 min given in Table 1. respectively, then replaced with isoamyl acetate for 20 min. The samples . were Discussion critical-point dried, coated with gold, and examined with a Hitachi S-450 scanning Plate sensory organs are similar to electron microscope. the domes of the sensilla campaniformia in external morphology, but the internal Results structures of these two sets of organs are distinctly different. Snodgrass ( 1926) con­ Sensory plaque organs in Tettigome­ cluded that the plate sensory organ did tridae differ from those in other families not evolve from the sensilla campanifo­ of Fulgoroidea in having a cuticular ring rmia. The porous plate organs could have without denticles and a porous plate evolved from the sensilla basiconica without plaques. The 4 types of this organ through reduction or from the sensilla observed are described below:. placodea. This plate type is the simplest Type I : The cuticular ring plain; the sensory plaque organ in Fulgoroidea. porous plate outwardly expanded margin­ Marshall and Lewis ( 1971) considered the ally (Figs.2, 3, 11). sensory plaque organs of other types on The cuticular ring not elevated, sur­ fulgoroid antennae to be derived from face plain. Margins of porous . plate porous plate organs. strongly expanded outwardly, expanded In this study the sensory plaque portion about 1/5 the length of diameter organs of 15 species in 6 genera and 3 of median hole. Margin of porous plate subfamilies of this family have been strongly incurved, incurved portion fused examined. The family Tettigometridae is a with surface of cuticular ring. special group of Fulgoroidea possessing· Type II : The cuticular ring elevated; sensory plaque organs with the unique the porous plate not expanded, protruding feature of a cuticular ring without den­ from dorsal margin of ring (Figs.4, 5, 12). ticles; the porous plate is without plaque. The cuticular- ring elevated distinctly. However, we found 4 types of sensory Margins of porous plate not expanded plaque organs in this family. In type I, outwardly, protruding from dorsal margin the cuticular ring . plain is not elevated; of elevated cuticular ring directly. Mar- the porous plate is outwardly expanded

Table 1. Types and total number of sensory plague organs in Tettigometridae 'l'axon Plague organ types Number of plague organs Tettigometrinae Brachyceps laeta 25 Micrometrina baranii I , Il 13 Tettigometra costulata I , III (most) 14 Tettigometra hexaspina III 32 Tettigometra hispanica III 18 Tettigometra impressifrons I , II 26 Tettigometra obliqua III 21 Tettigometra picta I , Il 16 Tettigometra sulphurea III 37 Tettigometra eremi III 18 Tettigometra sp. III 15 Egropinae Egropa bengalensis III 130 Hildinae Hilda undata IV 63 Hilda patruelis IV 103 Euphyonarthex phyllostoma IV 82

marginally, with the expanded portion or apical 1/2 (Fig .4). Both types I and II about 1/5 the length of the diameter of are found in Tettigometrinae. But the the median hole (Fig.3). In type II, the plaque organs of several type II species cuticular ring is elevated (Fig.6) and the are usually not uniform. Types I and II porous plate retreated, protruding from may occur at 1 antenna of a species, for the dorsal margin of the cuticular ring example, Micrometrina baranii (Table 1). .directly. In type III, the cuticular ring is This may imply an intermediate process still elevated but the porous plate is of evolution. In type ill, the total number retreated once more; the space between of piaque organs of every pedicel are from the cuticular ring and porous plate is 14 to 37, distributed in the apical (Fig.7), deeply grooved. Type IV is nearly the apical 1/2 or 2/3 portion in Tettigometri­ same· as type III, except the elevated nae; there are 130 in Egropinae and they cuticular ring is irregular and it is nearly cover the entire surface. The obliquely ridged. This ridged state of plaque organs in Hildinae belong to type cuticular rings is inferred to evolve into IV; the nlimber of plaque organs of every the guard denticles of other families. pedicel are from 63 to 103, and they also Based on the above data, the evolutiona­ nearly cover the entire surface (Fig.9). ry trend of these 4 types of sensory plaque organs is proposed to be type The above data indicate that the I -+type II -+type ill -+type IV. total number and distribution of plaque The total number and distribution of organs are not related to the types. In sensory plaque organs ap.d their types are spite of the extensive structural vari­ not related, although, the total number of ations of plaque organs in the subfamily plaque organs of every pedicel in types I Tettigometrinae, it possesses a primitive and II are from 13 to 26, with most of character state in Tettigometridae. The these distributed in the apical 2/3 (Fig.1) subfamily Hildinae possibly represents

Antenna] plaque organs of Tettigometridae 39 the most advanced character state in this family. Morphol. & Embryol. 23: 159-168. Acknowledgments Emeljanov, A. F. 1990. An attempt of construction of phylogenetic tree of This study was financially supported the (Homoptera, Cicadi­ by the National Science Council (NSC), na). Entomol. Obozr. 69: 353-356. R.O.C. NSC 84-2321-B005-062. We also Marshall, A. T., and C. T. Lewis. 1971. thank Dr. Liang-Yih Chou, Taiwan Structural variation in the antennal Agricultural Research Institute, Taichu­ sense organs of fulgoroid Homoptera ng, Taiwan, for providing access to the Clnsecta). Zool. J. Linn. Soc. 50: scanning electron microscope, 181-184. O'Brien, L. B., and S. W. Wilson. 1985. References systematics and external morphology. pp. 61-102. In: L. R. Asche, M. 1987. Preliminary thoughts on Nault, and J . G. Rodriguez, eds. The the phylogeny of Fulgoromorpha Leafhoppers and Planthoppers. John ( Homoptera: Auchenorrhyncha). Wiley and Sons, New York. 500 pp. Proc. 6th Auchen. Meeting, Turin, Snodgrass, R. E. 1926. The morphology Italy, 7-11 Sept. 47-53. of insect sense organs and the sen­ Bourgoin, T. 1985. Morphologie ante­ sory nervous system. Smithsonian nnaire des Tettigometridae (Hemipte­ Inst. Misc. Collect. 77: 1-80. ra, Fulgoromorpha). Nouv. Revue. Yang, C. T., and W. C. Hsieh. 1994. The Entomol. (N.S.) 2: 11-20. origin of the polymeri~ed flagellum of Bourgoin, T., and V. Deiss. 1994. Sen­ Fulgoroidea (Homoptera). Chinese J. sory plate organs of the antenna in Entomol. 14: 529-533. the Meenoplidae-Kinnaridae group Recefred for publication December 6, 1995; (: Fulgoromorpha). Int. J. Revised manuscript accepted February 10, 1996.

4-X.~~-i!i-~~~#1511!lit.:t..~~ 1U%-~~3, 1f.JJl~f:3~~~~ 0 §it-~ : '*­ Jt•+· ,~~4.:t..•·~~-·;§f;~~:'*-Jt«-ff-~,~~-~-·'~-*-It«z ;lifi'#-~~; §it;.~: -*-It•-ff-~' +i't, ~.:rL•~-*-Jt«aA~Ji1}-MJ ; §it~~: Ft.ff-~.:t..

-*-It•*~~:ftJLYJlJz:f-~>'r, ~~j{'-;r;;.~ o w..:iti!.~~~Jf-#z~Jiif;-, Jl:l:.;ft~~3z ~~4··-~§f;--~-_;_-~~o ~-8~:~~~tj-,~~,~~~~3o