Species Diversity. 1999, 4. 43 61

Geographic Variation of the Brachypterous Grasshopper Parapodisma setouchiensis Group in Western , with Its Taxonomic Revision

Yasushi Kawakami'

Department ofBiology, Faculty ofEducation, Tottori University, Tottori, 680-0945

(Received 10 March 1997; Accepted 6 July 1998)

The Parapodisma setouchiensis group (Catantopidae) is revised based on geographic variation in external morphology. This group appears to constitute a single polytypic species, P. setouchiensis Inoue, consisting of four geographic forms (Basic, Mt. Hyonosen, Tanba, and Yamato). Four taxa, Parapodisma tanba, P. yamato, P. hyonosenensis hyonosenensis, and P. hyonosenensis kibi, are treated as junior synonyms of P. setouchiensis. The polarity of character states in the P. setouchiensis group was inferred from the distribution pattern of the geographic forms. All pairs of adjacent forms intergrade through relatively narrow zones that may have originated from secondary contact. In two genital characters (triangular marking and cercus morphology), there are clines with different ranges across the boundary between the Tanba and Mt. Hyonosen forms. Key Words: geographic variation, brachypterous grasshopper, Parapodisma setouchiensis group, morphology, taxonomic revision, transitional zone, hybrid

zone.

Introduction

The Parapodisma setouchiensis group is a series of brachypterous grasshoppers which is indigenous to Japan and adjacent islands. The group is mainly distributed in the Japanese Archipelago from Aomori Prefecture to Yakushima Island, and also in Cheju Island of the Republic of Korea. Of the species or species-groups belonging to the genus Parapodisma, this group has the widest distribution. Tominaga et al. (1996) mentioned that the P. setouchiensis group comprises five taxa all having mutually allopatric or parapatric distributional ranges: Parapodisma setouchiensis Inoue, 1979; P. tanbaensis Tominaga and Kano, 1989; P. yamato Tominaga and Storozhenko, 1996; P. hyonosenensis hyonosenensis Tominaga and Kano, 1996; and P. hyonosenensis kibi Tominaga and Kano, 1996. However, classification of the group remained unclear, since its geographical variation in external characters is consider able and had not yet been examined in detail. The purpose of the present paper is first to determine the pattern of geographic variation of the P. setouchiensis group mainly around the eastern part of the Chugoku mountains, western Honshu, where the group exhibits its highest morphological diversity. The second purpose is to revise this polymorphic and taxonomically intractable group. In this paper, I will treat this group as a single species comprising four geographic forms, and, from the patterns of geographic variation, infer the origins of the transitional zones for various characters found in the eastern Chugoku

"Present address: Tottori West Technical High School, Kita 3-250, Koyama-cho, Tottori-shi, Tottori, 680-0941 Japan 44 Yasushi Kawakami mountains.

Materials and Methods

A total of 409 specimens was collected from 46 localities (Fig. 3) in western Honshu from July to September in 1994 and 1995. The specimens were preserved in 80% ethanol and used for the measurement of external characters. All the specimens examined and localities where they were collected are listed in the Appendix. Each sample is designated by the code number given in the Appendix. Males: Males were collected from all 46 localities. The average sample size for males per locality was 6.9. Eight morphological characters shown in Figure 1 were measured for each male specimen. Body length, head width, pronotum length, fore wing length, and hind femur length were measured by using a vernier caliper. The lengths of the subgenital plate and triangular marking (a dark mark on the dorsal subgenital plate) were measured with a micrometer installed on a stereo-microscope. The left cercus in lateral view was accurately sketched with a drawing apparatus, and the angle between its distal protuberance and basal part (Fig. 1) was then measured. The eight characters were compared in detail among populations. Since the fore wing length is supposedly correlated with the size of the thorax, the character state of fore wing length was expressed as the ratio of the fore wing length to the pronotum length. In comparing cerci, the shape and the angle between the distal process and the base of the cercus were used (Fig. 1). The data for 1994 and 1995 were pooled, since no significant between-year difference was detected in any of the eight characters in samples from locality 13 where the largest number of males was obtained each year (13 and 16 males, respectively; Kolmogorov-Smirnov test, P>0.20). Females: Females were obtained from 34 localities. Five characters (body length, head width, pronotum length, fore wing length, and hind femur length) were measured for each female using the same procedures for males (Fig. 1).

Morphological Variation

1. Body size Of the eight characters measured, body length (BL), head width (HW), pronotum length (PL), and hind femur length (HFL), all of which are correlated with body size, showed no particular geographical trend along the same latitudes in either males or females. The body size of univoltine insects often varies with altitude or latitude (Masaki 1996). Hence the relation of the four characters to the altitudes of the localities was analyzed in the univoltine P. setouchiensis group. The influence of latitude was ignored because all the localities were at almost the same latitude, from 34° 50' to 35° 30' north. All the characters except for BL of females showed a negative correlation with altitude [BL: male r2= 0.48, P<0.01; female r2= 0.10, P>0.05. HW: male (Fig. 2) r2= 0.69, P<0.01; female r2= 0.50, P<0.01. PL: male r2= 0.54, P<0.01; female r2= 0.21, P<0.01. HFL: male 1^ = 0.54, P<0.01; female r2= 0.23, P<0.01]. The reason for the absence of correlation between female BL and altitude may be the Geographic variation of a grasshopper 45

ca

tml;;[

Fig. 1. Eight characters of the P. setouchiensis group measured for the analyses of geographic variation. Abbreviations: BL = body length, CA = cercus angle, HFL = hind femur length, HW = head width, PL = pronotum length, SPL = subgenital plate length, TML = triangular marking length, WL = fore wing length. 46 Yasushi Kawakami large variation in female BL that results from the different degree of ovarian development among individuals. Of all the characters, HW showed the strongest correlation with altitude in both males and females (Fig. 2).

2. Triangular marking The triangular marking (TM) of males varied geographically (Figs 4-6). It was distinct in western and eastern populations but was obscure or absent in the middle part of the area surveyed. Figure 5 displays the geographic pattern of variation in TML. Populations 1-8 and 43-46 consisted of individuals with a prominent TM (Fig. 6A, C), about 0.4 mm long, while populations 22-39 consisted almost exclusively of individuals without a TM (Fig. 6B). In the two zones comprising populations 9-21 and 40-42, TML was highly variable (Figs 4A, 7). In each of these two zones a steep cline was found in the development of TM (Figs 4, 5). One transitional zone, comprised of populations 9-21, extends from Mt. Jubo (Shikano-cho, Tottori) south to the northern part of city. The other zone, including populations 40-42, occupies a small area around a watershed between the Yura and Kako Rivers.

3. Cercus Figures 4B and 8 show the geographic variation in the shape and the angle (lateral view) of the cerci in males. The tip of the cercus became slenderer and the angle became smaller eastward, but the pattern of geographic variation was some what different between the two characters. The tip was broad in western populations 1-9 whereas it was relatively slender

4.8 y=-7.3xl0"4x+4.7 r2=0.69(r=-0.83) 4.7 P < 0.01 ^o *°«° o 4.6 ^ o o Oo> o 4.5 o ° O ° o O o 5 4.4 8^ z 4.3 oo OlSsQo o

4.2

4.1 o 4 100 200 300 400 500 600 700 800 Altitude (m) Fig. 2. Relationship of male head width to the altitude of localities in the P. setouchiensis group. Each sample is represented by the population mean (open circle). All 46 samples listed in the Appendix are included. o

usedforthemorphologicalanalyses.Eachsampleisshownbythecodenumbergiven Fig.3.Provenanceofsamplesof theP.setouchiensisgroup in the Appendix. 48 Yasushi Kawakami

A. Triangular marking length uii

''iiJHjj..*...*...** il

i • • • • i

160 t 150 j T B. Cercus angle

60 lil:"!"""!!..!.,!.,,..!.o» 120 . - 110 I ± *I < 100 w. ° 90 rt 80 Jlii.! 70 I ••' • I

1.2 C. Subgenital plate length ? 1.1 6 1 _j .9 a. 0) .8 .7 Xk0

.6 i > ••• i i • • • • i

1.6 D. Fore wing length / Pronotum length S 1.5 6 1.4 6 1.3 6 >-' 1.2 _j Q. 1.1 "^ -1 1 £ .9 i'!.jrt^p"" " 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 Locality numbers Fig. 4. Geographic variation of four characters in males of the P. setouchiensis group. Code numbers for localities correspond to those in Fig. 3 and localities are approximately arranged from west (left) to east (right). Eachsample is represented by the mean (circle) and the range of 1 SD (bar). a

OKAYAMA

Fig. 5. Relative frequencies of three grades of length of male triangular marking in the P. setouchiensis group. The three grades are given in the left box. Circle size shows the number of examined individuals, as illustrated in the right box. Gray section (B) of circles denotes the proportion of specimens that showed intermediate conditions. 50 Yasushi Kawakami

B Fig. 6. Male triangular marking of the P. setouchiensis group (dorsal view). A, Basic form (Yabitsu, Tottori, Loc. No. 5). B, Mt. Hyonosen form (Mt. Hyonosen, Tottori, Loc. No. 29). C, Tanba form (Miwakare Park, Hyogo, Loc. No. 43). Scale bar= 1 mm.

distinct TM intermediate TM noTM

Fig. 7. Variation of male triangular marking in a population (Obata, Tottori, Loc. No. 13) between the Basic form (with TM) and the Mt. Hyonosen form (without TM) of the P. setouchiensis group (dorsal view). TM = triangular marking. Scale bar=l mm. in populations 20-46. In populations 10-19, the shape of the cerci was variable even within a single population and showed all intermediate conditions between the two extremes (Fig. 8). The cercus in populations 1-33 was bent slightly or moderately whereas that in populations 42-46 was bent very sharply (Figs 4B, 8).

4. Subgenital plate The subgenital plate showed a complicated geographic pattern (Fig. 4C). It was longer (ca. 1 mm) in western populations 1-12 and eastern populations 36 and 37. It was shorter though fairly variable (ca. 0.7-0.9 mm) in populations from the middle part and the easternmost part of the studied range. The shortest subgenital plates were found in populations 17 and 27. Geographic variation of a grasshopper 51

38 39 Fig. 8. Geographic variation of male cercus (left, lateral view) in the P. setouchiensis group. Code numbers for localities correspond to those in Fig. 3 and localities are arranged approximately from west to east. Scale bar= I mm.

5. Fore wing Since males and females showed similar trends, only the results for males are mentioned. As shown in Figure 4D, fore wing length relative to pronotum length showed a geographic pattern opposite to that found in the subgenital plate. Individuals with short fore wings were seen in the westernmost and easternmost populations. Fore wings were longer in populations from the middle part. The longest fore wings were found in populations 19 and 31.

Discussion

1. Taxonomic considerations Tominaga et al. (1996) recognized five allopatric or parapatric taxa in the P. setouchiensis group on the basis of external characters, and they classified them into four species, one of which consists of two subspecies. However, two lines of evidence support the idea that, of these five taxa, four (Parapodisma setouchiensis, P. tanbaensis, P. hyonosenensis hyonosenensis, and P. h. kibi) should be treated as one and the same species, Parapodisma setouchiensis: (1) These four taxa correspond to P. setouchiensis (populations 1-21), P. tanbaensis (41-46), P. hyonosenensis hyonosenensis (10, 13, 21-23, 26-30, 32-40), and P. h. kibi (9, 11, 12, ,14-20, 24, 25, 31) in this paper. The four "taxa" intergrade among each other, with transitional zones in various 52 Yasushi Kawakami characters including male triangular markings, and it is impossible to find any gaps in these transitional zones (Fig. 4). (2) Male genitalia in this group are very similar to one another (Fig. 9; Kano 1992; Tominaga et al. 1996). Although Tominaga et al. (1996) stated that the shape of the concealed part of the male external genitalia differs slightly between P. h. hyonosenensis and P. h. kibi, detailed examination in the present study revealed that the difference was not consistent (Fig. 9B). Tominaga et al. (1996) stated that the remaining taxon, P. yamato, which is distributed in Honshu from Aomori Prefecture to the Kinki District, is very similar to the holotype of P. setouchiensis (Mitsugi-cho, Hiroshima Pref.), except for the condition of the fore wings. In the Kinki District, the fore wings of P. yamato sensu Tominaga et al. (1996) are much longer than those of the holotype of P. setouchiensis. However, the wings of P. yamato become gradually shorter eastward, and individuals of P. yamato from Tohoku District are virtually indistinguishable from the holotype of P. setouchiensis (Kano 1986, 1992; Tominaga et al. 1996). Moreover, in fore wing length there is a steep and continuous cline where the long-winged form in the Kinki District (P. yamato) is replaced by the short-winged form (P. setouchiensis) along the coast of the Ki'i Peninsula (Tominaga et al. 1996; Kawakami unpublished). These facts suggest that P. yamato should also be treated as a local form of P. setouchiensis.

The system proposed by Tominaga et al. (1996) and that adopted in this paper are listed in Table 1. Distributions and transitional zones of the forms of the P. setouchiensis group are shown in Figs 10 and 11.

2. Direction of geographic differentiation Populations of the two most distant areas (Tohoku-Kanto-Chubu Districts and Chugoku--Kyushu Districts) of the Basic form share the same state in some characters, while populations between these areas have a different character state (Fig. 10). Moreover, many islands around the three main islands (Honshu, Shikoku,

Fig. 9. Parapodisma setouchiensis, dorsal view of male phallic complex (genitalia). A, Basic form (Aidani, Tottori, Loc. No. 6); B, Mt. Hyonosen form (Amedaki Falls, Tottori, Loc. No. 28); C, Tanba form (Shogoji, Kyoto, Loc. No. 45). Scale bar= 1 mm. Geographic variation of a grasshopper 53 and Kyushu) of Japan are inhabited only by the Basic form. This geographical pattern is not unusual in animals with low vagility (Tsurusaki 1985). Since the P. setouchiensis group cannot fly, their vagility must be low. Application of the parsimony principle to this spatial pattern suggests that the character states possessed by the Basic form are plesiomorphic, while those found in the intervening area are apomorphic. The polarity of some characters, based on this reasoning, is tabulated in Table 2. These geographic patterns of differentiation may be explained by the "stasipatric model" of speciation advocated by White (1968, 1978): (1) the origin of a new character and its fixation into a population should happen even without extrinsic (geographic) barriers in organisms with low vagility, and (2) the area where the character first appears may be in the center of the distributional range, where populations are subdivided. This model is not widely accepted as a theory of speciation, but may explain the process of geographic differentiation within a species.

3. The possible formation process of the transitional zones found in western Honshu It is thought that a transitional zone in morphology may be produced by (1) hybridization between two morphologically divergent populations (hybrid zone in a strict sense; Endler 1977), (2) the presence of a steep cline in ambient conditions, and (3) a diffusion process of neutral characters (Nei 1987). Of these, the second factor can be dismissed for all cases in the P. setouchiensis group in western Honshu, since no drastic change in either climate or vegetation is observed across each transitional

Table 1. Synopsis of the systems adopted by Tominaga et al. (1996) and by the present paper. Tominaga et al. (1996) Present paper P. setouchiensis Inoue P. setouchiensis Inoue, 1979 Basic form P. yamato Tominaga and Storozhenko, 1996 Basic form and Yamato form P. hyonosenensis hyonosenensis Tominaga and Kano, 1996 Mt. Hyonosen form P. hyonosenensis kibi Tominaga and Kano, 1996 Mt. Hyonosen form P. tanbaensis Tominaga and Kano, 1989 Tanba form

Table 2. Plesiomorphic and apomorphic alternatives of three of characters in the P. setouchiensis group Character Plesiomorphic state Apomorphic state

absent Triangular marking (male) distinct (Mt. Hyonosen form)

bend strongly dorsad Cercus (male) bend gently (Tanba form and a part of Mt. Hyonosen form)

relatively long Fore wing short (Yamato form) 54 Yasushi Kawakami

YURA-KAKO R.

(janba form)

(Basic form)

(Basic form) (Yamato form)

Fig. 10. Distribution of the P. setouchiensis group. Compiled from Kano (1992), Tominaga et al. (1996), and the present paper. Arrows show the position of geographic dines for certain morphological characters. Further explanations in text.

zone. The first possibility is most likely for the formation of the transitional zones in the three investigated characters (triangular marking, cercus, and subgenital plate) in Tottori and Okayama Prefectures, because the locations of the transitional zones of the three characters correspond well (Fig. 11). The fact that presumed hybrid zones or distributional borders between closely related species of various animals such as damselflies, harvestmen and land snails have been known in this area (Suzuki and Kadowaki 1988; Tsurusakie/ al. 1991; Kiyosueeia/. 1976) also supports the idea, though their exact positions do not strictly agree. On the other hand, the situation in the transitional zones around Kyoto-Hyogo Prefectures is somewhat complicated. A narrow cline, ca. 7 km wide, for the triangu lar marking is located in the upper courses of the Yura and Kako Rivers, where the lowest watershed (ca. 100 m) in Japan (Figs 3, 11) is found. Okada and Takahashi (1969) and AGCJ (1990) showed that the main stream of the present was a part of the old Kako River and flowed southward (the Paleo-Yura-Kako River) about 300,000 to 200,000 years ago (from the Mindel-Riss interglacial age to the Riss glacial age). Therefore, the presence of these rivers may have played an important role as an effective geographical barrier to dispersal of flightless grasshoppers. The transitional zone in cercus morphology may have been formed as a consequence of hybridization between two formerly distinct forms after the emergence of the watershed (150,000 to 100,000 years ago, during the Riss-Wurm interglacial age), which permitted gene flow between the eastern and western populations. However, Geographic variation of a grasshopper 55

triangular I a i marking ^^r

cercus

Fig. 11. Transitional zones of triangular marking and cercus in males of the P. setouchiensis group in western Honshu. Hatched areas show the transitional zones for the triangular marking. Arrows denote the direction of clines in the cercus angle, which becomes gradually gentler from the watershed of the Yura-Kako Rivers toward the broken line. Further explanations in text.

why the slope and position of the cline in cercus morphology do not coincide with those containing to the triangular marking is still unclear. Introgression of genes governing cercus morphology beyond the transitional zone for the triangular marking might explain this pattern.

Descriptions

Instead of "subspecies" I use the term "form" for geographical variants that are distinguishable from other conspecifics by certain morphological characters. The reasons are as follows: (1) unlike "species", "subspecies" is a rather arbitrary concept lacking objective criteria; and (2) classifying continuously varying organisms into 56 Yasushi Kawakami subspecies often obscures dynamic patterns of geographic variation in characters, thus impeding the resolution of biological issues, such as speciation (Wilson and Brown 1953; Key 1981; Futuyma 1986, pp. 107-109; also see O'Brien and Mayr 1991, for a defense of the sensible use of the term "subspecies"). The use of the term "form" instead of "subspecies" is also subject to the same criticism; however, this term requires no formal taxonomic treatment and can be easily changed when revisions are made in the future.

Remarks 1) Synonym lists cite only the original descriptions and some important papers. 2) The collection data are represented by the code numbers in the Appendix. 3) Abbreviations: ELEU = Entomological Laboratory, College of Agriculture, Ehime University, Ehime; OMNH = Osaka Museum of Natural History, Osaka; BL = body length; HW = head width; PL = pronotum length; WL = fore wing length; HFL = hind femur length.

The Parapodisma setouchiensis group

This group comprises only one species, which is divided into four geographic forms.

Parapodisma setouchiensis Inoue, 1979 (Figs 4-11)

Parapodisma setouchiensis Inoue, 1979, p. 59, fig. 1, pi. 2A (type: Ichi, 200m alt., Mitsugi-cho, Mitsugi-gun, Hiroshima Pref., in ELEU, not examined); Inoue 1985, p. 129, figs 24, 55, 86, table 9; Tominaga 1983, p. 29, figs 1, 2, 7A-D; Kano 1992, p. 80; Tominaga, Storozhenko and Kano 1996, p. 1, figs 4-7, 13, table 1. Parapodisma tanbacnsls Tominaga and Kano, 1989, p. 1, figs 1-29 (type: Yakumo-ga- hara, 900m alt., Mt. Hira, Shiga Pref., in OMNH, not examined); Kano 1992, p. 81; Tominaga, Storozhenko and Kano 1996, p. 1, figs 4-6, table 1. NEW SYNONYMY Parapodisma yamato Tominaga and Storozhenko, in Tominaga, Storozhenko, and Kano 1996, p. 1, figs 1-7, table 1 (type: Kurotogadani, Mt. Kongo, Chihaya- akasaka-mura, Minamikawachi-gun, Osaka pref., in OMNH, not examined). NEW SYNONYMY Parapodisma hyonosenensis hyonosenensis Tominaga and Kano, in Tominaga, Storozhenko, and Kano 1996, p. 11, figs 8, 9, 12, 13, tables 1-3 (type: Kawakami- Aokurajinja, Mt. Aokura, Asako-cho, Asako-gun, Hyogo Pref., in OMNH, not examined). NEW SYNONYMY Parapodisma hyonosenensis kibi Tominaga and Kano, in Tominaga, Storozhenko, and Kano 1996, p. 15, figs 10-13, tables 1-3 (Hako-Higashitomitani, Okutsu-cho, Tomata-gun, Okayama Pref., in OMNH, not examined). NEW SYNONYMY Parapodisma dairisama: Hiura 1977, p. 81; Hiura 1979, p. 8, fig. 3; Kano 1983, p. 37; Tominaga 1983, p. 29, figs 1, 5, 7K. Parapodisma sp. (Yamato-fukibatta): Hiura 1979, p. 8, fig. 3; Kano 1983, p. 37, figs 1-4; 1986, p. 20, figs 18-26, 37; 1992, p. 84; Tominaga 1983, p. 29, figs. 1, 6. Geographic variation of a grasshopper 57

Parapodisma sp. (Hyonosen-fukibatta): Tominaga 1983, p. 29, figs 1, 4, 7E-J; Kano 1992, p. 81.

Diagnosis. The male is easily separable from all other species of the genus Parapodisma by having a phallic complex (genitalia) with a pincer-shaped tip (Fig. 9). Karyotype. 2n (o71) = 21 (Miyoshi-shi, Hiroshima pref.) (Inoue 1985). Distribution. Japan (from Aomori Pref. to Yakushima Island) and Cheju Island of the Republic of Korea (Fig. 10) (Kano 1992; Tominaga et al. 1996). Biology. This species is univoltine and hibernates as eggs. Adults appear from late-June to mid-July and are found on shrubs or undergrowth along the forest edge of low mountains. The host is discotyledon leaves; they rarely eat leaves of mono cotyledon plants. They are not found at altitudes of more than ca.l200m in Chugoku District, Honshu.

1. Basic form [Figs 4 (Nos. 1-8), 5, 6A, 8 (Nos. 1-8), 9A, 10, 11]

Diagnosis: This form differs from the Yamato form in having shorter fore wings, which barely reach to the second or third abdominal tergite in general. The male is separable from those of the Mt. Hyonosen and Tanba forms in having a distinct triangular marking (Fig. 6A) and relatively straight cerci with a wide tip (Nos. 1-8 in Fig. 8). The subgenital plate in the male is relatively long. Measurements (mm): Sample Nos. 1-8 (A5JJ, 14££): BL, Tenjin River (Tottori Pref.) and (Okayama Pref.)], Shikoku, Kyushu, Oki Islands, Tsushima Is., Iki Is., the Goto Archipelago, Tanegashima and Yakushima Islands, the Izu Archipelago; and Cheju Island of the Republic of Korea (Fig. 10). This form intergrades with the Mt. Hyonosen form in the area encompassed by the Tenjin-Asahi Rivers and the Sendai-Yoshii Rivers, and with the Yamato form on the west coast of the Ki'i Peninsula (Figs 10, 11). Remarks: The fore-wing length decreases northeastwards from the border between the Kinki and Chubu Districts (Fig. 10) (Kano 1986, 1992; Tominaga et al. 1996). The holotype of P. setouchiensis Inoue belongs to this form. Specimens examined: Sample Nos. 1-8.

2. Mt. Hyonosen form [Figs 4 (Nos. 22-39), 5, 6B, 8 (Nos. 22-39), 9B, 10, 11]

Diagnosis: This form is distinguishable from all other forms by the lack of a triangular marking on the male subgenital plate (Fig. 6B). Males have cerci with a more slender tip than those of the Basic form (Nos. 22-39 in Fig. 8). The fore wing is relatively short, reaching to the 2nd or 3rd abdominal tergite at most. 58 Yasushi Kawakami

Measurements (mm): Sample Nos. 22-39 (114c/1S, 44££): BL, f 20.5-28.2, $ 27.3-38.5; HW, S 4.00-4.95, £ 4.63-5.61; PL, S 5.03-6.60, * 6.54-8.76; WL, S 5.06-8.65, * 5.89-9.85; HFL, o71 11.5-14.4, $ 13.9-18.3. Distribution: Western Honshu (approximately the area between the Sendai- Yoshii Rivers and the Yura-Kako Rivers) (Figs 10, 11). This form intergrades with the Basic form in the area surrounded by the Tenjin-Asahi Rivers and the Sendai-Yoshii Rivers, and with the Tanba form in the area around the watershed between the Yura and Kako Rivers (Fig. 11). Remarks (see Figs 3, 4, 8, 11): In the area near the Yura and Kako Rivers the angle of the cerci is as sharp as that of the Tanba form, but it becomes gentler toward the center of the distributional range of this form (Figs 4B, 8). Specimens examined: Sample Nos. 22-39.

3. Tanba form [Figs 4 (Nos. 43-46), 5, 6C, 8 (Nos. 43-46), 9C, 10, 11]

Diagnosis: In males this form is distinguished from the Mt. Hyonosen form in having a distinct triangular marking on the subgenital plate (Fig. 6C). Moreover, the form differs from both the Basic and Yamato forms in having a male cerci bending sharply dorsad at an angle of about 80° (Nos. 43-46 in Fig. 8). The fore wing is short, never reaching to the third abdominal tergite. Measurements (mm): Sample Nos. 43-46 (19a71 o71, 8££): BL, Yodo River) (Fig. 10). This form intergrades with the Mt. Hyonosen form in the area around the watershed of the Yura-Kako Rivers (Fig. 11). Specimens examined: Sample Nos. 43-46.

4. Yamato form (Fig. 10)

Diagnosis: This form is distinguished from all other forms in having longer fore wings. The fore wings reach the 4th-6th abdominal tergite. Males bear a distinct triangular marking and relatively straight cerci. Distribution: Western Honshu (roughly from Lake Biwa and the Yodo River to the border between the Kinki and Chubu Districts, excluding the western coast of the Ki'i Peninsula) (Fig. 10). This form intergrades with the Basic form on the west coast of the Ki'i Peninsula (Fig. 10).

Acknowledgements

I wish to express my sincere gratitude to Dr. Nobuo Tsurusaki, Tottori Geographic variation of a grasshopper 59

University, for his pertinent guidance throughout the present study and critical reading of the manuscript. Cordial thanks are also due to Dr. Saburo Akagi, Prof. Emeritus of Tottori University, for his helpful suggestion on the geology of Japan; Prof. Masashi Inoue, Imabari Meitoku Junior College, Ehime, and Mr. Yasutsugu Kano, Mie, for their help in obtaining literature on the P. setouchiensis group, and to two anonymous reviewers who helped much in improving the maunscript.

References

AGCJ (The Association for the Geological Collaboration in Japan, Kyoto branch) (Ed.) 1990. Time Travel to 50 Million Years ago in Kyoto (2nd Ed.). Houritsu-bunka-sha, Kyoto, 171pp. [In Japanese] Endler, J. A. 1977. Geographic Variation, Speciation, and Clines. Princeton University Press, Princeton, New Jersey, 246pp. Futuyma, D. J. 1986. Evolutionary Biology (2nd Ed.). Sinauer Associates, Inc., Sunderland, 600pp. Hiura, 1.1977. Locustidae, Pp. 77-81. In: Ito, S., Okutani, T. and Hiura, I. (Eds) Colored Illustrations of the Insect ofJapan Vol.2. Hoiku-sha, Osaka, 385pp. [In Japanese] Hiura, I. 1979. The insects more than 1 cm (8), Acridoidea (2). Nature Study 25(1): 5-10. [In Japanese] Inoue, M. 1979. Two new species of genus Parapodisma from western Japan (Orthoptera: Acrididae). Proceedings of the Japanese Society of Systematic Zoology 16: 58-65. Inoue, M. 1985. A taxonomic revision of Japanese Acridoidea (Orthoptera) with special reference to their karyomorphology. Transactions of the Shikoku Entomological Society 17(3): 103-183. Kano, Y. 1983. Genus Parapodisma around Nahari City (2). Hirakura (Bulletin of the Mie-Kontyu-Danwakai) 27(3): 37-48. [In Japanese] Kano, Y. 1986. Podismini in the Tohoku region and its neighborhood (2). Nature of Tohoku 18: 18-23. [In Japanese] Kano, Y. 1992. Podismini, Pp. 60-93. In: Miyatake, Y. and Kano, Y. (Eds) Colored Illustrations of the Cicadas and Grasshoppers. Hoiku-sha, Osaka, 215pp. [In Japanese] Key, K. H. L. 1981. Species, parapatry, and the morabine grasshoppers. Systematic Zoology 30: 425-458. Kiyosue, T, Tanioka, H., Ishizaka, H. and Nakashima, R. 1976. A list of land snails in , Japan. Bulletin of the Tottori Prefectural Museum 13: 1-33. [In Japanese] Masaki, S. 1996. Geographical variation of life cycle in crickets (Ensifera: Grylloidea). European Journal of Entomology 93: 281-302. Nei, M. 1987. Molecular Evolutionary Genetics. Columbia University Press, New York, 512pp. O'Brien, S. J. and Mayr, E. 1991. Bureaucratic mischief: Recognizing endangered species and subspecies. Science 251: 1187-1188. Okada, A. and Takahashi, K. 1969. Geomorphic development of the drainage basin of the River Yura, western Honshu, Japan. Journal of Geography 78(1): 19-37. [In Japanese, with English summary] Suzuki, K. and Kadowaki, H. 1988. Geographical distribution of Mnais damselflies (Odonata, Calopterygidae) in Tottori Prefecture, Chugoku District, Honshu, Southwest Japan (I). Journal of the College of Liberal Arts, Toyama University (Natural Science) 21(1): 1-17. Tominaga, O. 1983. Let's examine the genus Parapodisma (PART II). Sukashiba (Bulletin of the San'in-Mushi no-Kai) 20: 29-30. [In Japanese] 60 Yasushi Kawakami

Tominaga, O. and Kano, Y. 1989. A new Parapodisma species (Orthoptera: Catantopidae) from Japan. AKITU, Kyoto Entomological Society 102: 1-10. Tominaga, O., Storozhenko, S. Y. and Kano, Y. 1996. Two new species and a subspecies of the genus Parapodisma (Orthoptera, Acrididae) from Japan. Tettigonia 1(1): 1-23. Tsurusaki, N. 1985. Geographic variation of chromosomes and external morphology in the montanum -subgroup of the Leiobunum curvipalpe -group (Arachnida, Opiliones, Phalangi- idae) with special reference to its presumable process of raciation. Zoological Science 2: 767-783. Tsurusaki, N., Murakami, M. and Shimokawa, K. 1991. Geographic variation of chromosomes in the Japanese harvestman, Gagrellopsis nodulifera, with special reference to a hybrid zone in western Honshu. Zoological Science 8: 265-275. White, M. J. D. 1968. Models of speciation. Science 159: 1065-1070. White, M. J. D. 1978. Modes of Speciation. Freeman and Company, SanFrancisco, 455pp. Wilson, E. O. and Brown, W. L. 1953. The subspecies concept and its taxonomic application. Systematic Zoology 2: 97-111.

Appendix

List of specimens (316a71 a71, 93 •¥--?•) of Parapodisma setouchiensis examined in the present study. Data for each sample are given in the following order: Code number for the sample, locality (TP = Tottori Pref.; OP = Okayama Pref.; HP = Hyogo Pref.; KP = Kyoto Pref.), altitude of locality: number of individuals examined o71 a71 / £ -¥-, date collected, collector (YK = Yasushi Kawakami). (1) Okiya, Saihaku-cho, TP, 320m: 5/3, 14-VIII-1995, YK. (2) Ikkoganaru, Tohaku-cho, TP, 490m: 7/3, 29-VIII-1995, YK. (3) Hatagoraru, Kamogawa-cho, OP, 240m: 2/3, 9-VIII-1995, YK. (4) Yubara Spa., Yubara-cho, OP, 310m: 5/2, 16-VIII- 1995, YK. (5) Yabitsu, Sekigane-cho, TP, 240m: 5/1, 8-VIII-1994, YK. (6) Godani, Misasa-cho, TP, 180m: 6/2, 24-VII-1995, YK. (7) Yabara, Shikano-cho, TP, 130m: 6/0, 15-VII-1994, YK. (8) Western side of the Kochi River, Kochi, Shikano-cho, TP, 200m: 9/0, 27-VII-1994, YK. (9) Kijiyama, Misasa-cho, TP, 460m: 11/1, 26-VII-1994, YK. (10) Eastern side of the Kochi River, Kochi, Shikano-cho, TP, 290m: 10/0, 19-VII- 1994, YK. (11) Kuriso, Misasa-cho, TP, 570m: 8/0, 2-VIII-1994, YK. (12) Tateo, Tomi-son, OP, 510m: 6/0, 25-VIII-1994, YK. (13) Obata, Shikano-cho, TP, 300m: 13/0, 19-VII-1994, YK : 16/2, 10-VIII-1995, YK. (14) Ningyo Pass, Karni-saibara-son, OP, 600m: 5/4, 10-VIII-1995, YK. (15) Iruma, Tomi-son, OP, 400m: 6/0, 25-VIII-1994, YK. (16) Baba, Tomi-son, OP, 450m: 5/0, 25-VIII-1994, YK. (17) Nishi-seijitsu, Yoshii-cho, OP, 300m: 8/1, 27-VII-1995, YK. (18) Koki, Yoshii-cho, OP, 160m: 12/3, 27-VII-1995, YK. (19) Otani, Aida-cho, OP, 100m: 6/4, 17-VIII-1995, YK. (20) Endo, Kami-saibara- son, OP, 730m: 7/4, 10-VIII-1995, YK. (21) Azo, Tottori-shi, TP, 320m: 5/0, 18-VII- 1994, YK. (22) Mitaki Falls, Kawahara-cho, TP, 580m: 9/3, 24-VII-1994, Nobuo Tsurusaki. (23) Yodo, Saji-son, TP, 300m: 8/0, 2-V1II-1994, YK. (24) Southern foot of Mt. Nagi, Nagi-cho, OP, 500m: 7/3, 17-VIII-1995, YK. (25) Northern foot of Mt. Nagi, Chizu-cho, TP, 670m: 6/6, 21-VIII-1995, YK. (26) Omori, Tottori-shi, TP, 120m: 9/0, 23-VII-1994, YK. (27) Oochidani Park, Tottori-shi, TP, 100m: 6/3, 31-VII-1995, YK. (28) Amedaki Falls, Kokufu-cho, TP, 450m: 8/1, 25-VII-1994, YK. (29) Western foot of Mt. Hyonosen, Tsukuyone, Wakasa-cho, TP, 750m: 5/0, 22-VIII-1994, YK. (30) Hikibara, Haga-cho, HP, 460m: 7/6, 25-VIII-1995, YK. (31) Shibiki Pass, Chikusa-cho, Geographic variation of a grasshopper 61

HP, 470m: 5/3, 23-VIII-1995, YK. (32) Suga, Yamasaki-cho, HP, 80m: 6/5, 8-VIII-1995, YK. (33) Hachi-kita Highlands, Ozasa, Muraoka-cho, HP, 470m: 6/0, l-VIII-1994, YK. (34) Kannabe Valley Park, Inaba, Hidaka-cho, HP, 480m: 4/4, 25-VIII-1995, YK. (35) Hasamaji, Yabu-cho, HP, 90m: 6/3, 19-VII-1995, YK. (36) Shiraito-no-taki Falls, Izushi-cho, HP, 140m: 5/3, 7-VIII-1995, YK. (37) Tozaka Pass, Aogaki-cho, IIP, 350m: 5/2, 31-VII-1995, YK. (38) Ashida, Aogaki-cho, HP, 130m: 8/1, 19-VII-1995, YK. (39) Kamo, Hikami-cho, HP, 120m: 4/1, 28-VII-1995, YK. (40) near Futasegawa Stream, 6e-cho, KP, 170m: 7/4, 7-VIII-1995, YK. (41) Kora, Hikami-cho, HP, 140m: 4/2, 28-VII-1995, YK. (42) Hikami, Hikami-cho, HP, 100m: 9/2, 19-VII-1995, YK. (43) Miwakare Park, Iso, Hikami-cho, HP, 110m : 2/1, 5-IX-1994, YK. (44) Arita, Oe-cho, KP, 50m: 7/0, 31-VII-1995, YK. (45) Shogoji, Fukuchiyama-shi, KP, 50m: 5/1, 1l-VIII-1994, YK. (46) Omi, Miwa-cho, KP, 160m: 5/6, 20-VII-1995, YK.