The LepidopterologicalSocietyLepidopterological Society of Japan utUma 7>'ans. Icpid. Soc. Jcif)an 58(l)i 109-125,January 2007 Discrimination and phenology of hilltopping butterflies on two mountains on the boundary between 0saka and Nara Prefectures, central Japan Sophie NAvEz* and Minoru IsHii Entomological Laboratory, Graduate School of Agriculture and Biological Sciences, Osaka Prefecture Unjversity, Gakuen-cho 1-1, Sakai, Osaka, 599-8531 Japan Abstract In order to discriminatc hilltopping butterflics and c!ucidatc thcir phenology, we fixcd, respeetively, 46 and 26 5-m radius virtual circles on the suinmit, subsummit and slope of Mt Katsuragi (960 m alt.) and Mt Nijo (2 peaks[ Medake, 474 m alt. aiid Odake, 517 m alt.) located on thc boundary bctwccn Osaka and Nara Prefeetures, centra] Japan. During annual surveys from spring to autumn in 2001-2002 on Mt Katsuragi and in 2002 on Mt Nijo, we used the mean t're- quency of visits during 5 min census periods in each obse-,ation circle as quantification method, A total of 55 species (8 farnilies) were ebserved and 29 species were common to the 3 peaks, with 53 species seen in Mt Katsuragj, 42 in Medake and 31 in Odake. On both mountains, most species were rare (Iow abundance). According to 2001 resu]ts from Mt Katsuragi, Pq)ilio machaon, Arg)'reus h}perbitts, Libythea celtis, Colias erate and L)'caena phlaeas were classificd as hilltup- "broad pers because their distributions were statistically biased on thc summit" (including summit and subsumrnit circles). However, the hil]topper status of the last three species remains controver- sia], On Mt Nijo 2002, VLtnessa indica, C>,nthia cardui, P, machaon. Papilio xuthus, Papilio bianor, Pc4)ilio hetenus. 7V>'n'iphatis xanthon'tetas, A. h)･perbius. Latupides boeticus and Hestina japonica were hilltopping. Although all those species were also recorded on Mt Katsuragi, data from 200 l and 2002 confirm tha(, on Mt Katsuragi, P. xuthLts, P. bianor, P. helenits and H. .iq,oni- ca were not hilltopping, All other Nijo's hMtoppers were also hilltopping in Mt Katsuragi (2001 andlor 2002 data). On the contrary, Parnat'a guttata and Luehdolfia,iaponica were hilltopping on Mt Katsuragi in 2002 but not on ML Nljo, where L. japonica was not recorded. C, erate. L. phlaeas and L. cettis were not hilltoppers on Mt Nijo. P. xuthus, H..iaponica and C, cardui were hilltopping on Medake but not on Odake. Though some hilltopping species were very abundant on the summit in the 3 seasons (P. machaon), or only 2 seasons (summer and autumn for A, h.}7]erbius, spring and summer for C, erate and L, celris) or 1 season (autumn for L. I)oetictts and P. guttata), variation ex- isted between peaks conceming the dominunee ranking ordcr of those specics. 0n the other hand, some hilltoppers such as V. indica, were rare or relatively rare on the 3 peaks in the 3 seasons, though still presenting gorne variabi]ity in relative abundanee and domjnance ranking status be- tweenpeaks. Key words Butterfi>,, Hilltopping, Mt Katsuragi, Mt Nijo, scasonal abundance, Japan. Introduction Hilltopping in butterfiies is traditionally viewed as a behaviour in which ma]es and virgin females seek and congregate on a prominence from the surrounding environment to mate (Shields, 1967; Lederhouse, 1982; Wickman, 1988). Low density species and species whose receptive females are widely dispersed in space and time practice the behaviour in order to produce enough individuals at each generation te mate (Shields, 1967; Scott,] 968; Alcock, 1983; Rutowski and Alcock, 1989), Hilltopping would be a default strategy, called male dominance po]ygyny, used by males when neither females ner the resources they use are clumped and thus cannot be economically monopolized by males at potential feeding, oviposition or emergence sites (Rutowski and Alcock, 1989), The female orientation hy- SCorrespondin.a author. E-mail: s][email protected] NII-Electronic Library Service The LepidopterologicalSocietyLepidopterological Society of Japan llO Sophie NAvE7 and Mjnoru IsHJi pothesis was suggested for explaining why peaktops would become rendezvous points (Alcock, 1987). Males were shown to adopt either a (non) tenitorial perching, patrolling or both mate-locating tactics (e. g. Jlapitio zelicaon) on hi]ltops (Shiclds, 1967). However, previous studies involving hilltopping butterfiies foeused on only one hilltop at a time and on the behavioural and distributional comparison of species from different taxo- nomic groups (e. g. butterfiies with bees, wasps, and flies) present on that hilltop (e. g. Alcock, 1983, 1984, 1985) or on only a small number of butterfiy species pertaining to the same genus (e, g. Veinessa spp. in Brown andAlcock, 1990) or family (e. g, Papilionidae in Pinheiro (1990(91)) and Turner (1990)), Thus it is necessary to make comparison among exclusively butterfly species (same and different frLmilies), among peaks, among seasons and among zones (summit, subsummit and slope) in each mountain to clarify if hilltopping is a uniquelstandardized phenomenon wi'th only one purpose and generated by only one set of factors, The present study was done to make the tetal list of species recorded on two mountains (and 3 hilltops) in Central Japan, and to identify which ones might be considered as (non) hilltoppers, Besides, it will check whether some species hilltop on one mountain but not on another in spite of the species' presence on both mountains, Butterflies are selected among other possible hilltopping groups such as Diptera, Hyrnenoptera, Coleoptera or Orthoptera (Shields, 1967) because of their easy survey, well-known taxonomy, ecology, ethology and life-cycle as well as their reputation as good indicator taxa whose incidence and abundance reflect even slight modifications in their environment (New, 1993), Sites belonging to the same geographical area (i. e, in the same type of landscape) will be chosen for comparison. Otherwise, other landmark, non-resource encounter sites than hilltops (e. g. forest-meadow edges, vegetation funnels, sidewalks, fbrcst clearings, gullies) might be used by species if the geographicaliy separated area displays (nearly) no hil]s in its landscape (Rutowski and Alcock, 1989; Brown and Alcock, 1990 (91); Alcock and Gwynne, 1988; Bitzer and Shaw, 1979). The three hilltops will also be selected according to their altitudinal differences, dis- tinct topography (small, flat hilltops vs 1arge, undulating ones) and contrasting vegetation types (forest edge vs bare-grassy). Study sites and methods a) Study sites and schedule The study was first conducted for 34 days firom April 23 to October 25, 2001 on Mt Katsuragi (or Ytimato-Katsuragi) (960 m alt) located at the frontier between Osaka and Nara Prefectures, central Japan (Fig. 1). The site vegetation was mainly characterized by decidu- ous broadleaved forests and coniferous plantations of Japanese cedar (Cfyptomeria japoni- ca) and cypress (Chamaecyparis obtt{sa) on the slopes, by bare and grassy (dominated by bamboo grass Pleioblast"s chino and Miscanthus sinensis) ground on the hilltop and by thickets of shrubs (especialry Rhododendron spp. on the upper half of southern slope) mixed with bamboo grass on the beginning of slopes surrounding the hilltop, We fixed 46 observation points at ditferent altitudjnal levels on the hill and on different tran- sects, and the frequency of visits (see definition below) for any encountered butterfly species within the range of 5-m radius circles around the 46 points (observation circles) (Fig, 2) was recorded (1 census session!day) during 10 min census periods in each circ]e from, on average, 9h30 to 15h30, The fbrest transect circles (slope) were obsei'ved on an- other day, in alternance with the summit and beginning of slopes (subsummit) censuses ses- gions. Each day a different itinerary for the 46 circles was followed so as to minimizc thc NII-Electronic Library Service The LepidopterologicalSocietyLepidopterological Society ofofJapan Japan 111 Discrimination and Phenology of Hilltopping Butterflies N ÷ 200 "300 3. i.2e 7 ROAD 200 300- s 500 m boslODAKE234 55l7rn 43lni .t--t-u- s･'tt N ".L3c-'xvt" N+ -k xs$tS;}ctl " i,l;ii)//i･.(lllillili)"M's'-i"x, S'L;:=H"-"Lt- Kobe v, " M$:g-.k$1'.EesE,)'} t t . .M...$.3..." 0e2iM,, mulem Fig. 1.Location of Mt Nljo and Mt Katsuragi (border of Osaka and Nara Prefectures) and arrange- ment of the observaLion circles o] the slope of Medake, subsummits and summits (see profile map) efMedake and Odake (Mt Nijo). On the bottom right map: grey shading=bare ground with seattered pebbles; dotted area=marble sundial; white area between the 2 con- centric circles=big gravel area. NII-Electronic Library Service The LepidopterologicalSocietyLepidopterological Society ofofJapan Japan 1]2 Sophie NAvEz and Minoru lsmi V'. 1 , L!rf'X'rlixx [L-Ti'N;v) ef N i 9 iN" " v` Kl 2 / t 'y pta tA c 1?tt- ts s"700 k,g-!-;--) ,-'5 ,2)'yk )ti 700 60C 500 40C 3OO ,xvx /ik if/l# ar 9m0 pm - 20rn 949m (l)mNe r' cu- op st e Emsu eoHgIg,CIS) Nsu. mx a S,g /-Iges :.. di pt Fig. 2. Arrangement ef thc observation circles along thc slopc, subsuinmits and suininit of Mt Katsuragi. A microtopographical protile of the summit transect is alse shown. Numbers framed by a square are circles checkcd only in 2002. Thc undcrscored nuiiibcr's rcpresenL circles checkcd only in 2001. 0n the lowcr map, circlcd numbcrs dcpict 5-m radius obser- vation circles. bias associated with the time of day when records are taken at a particular location on the hill. In 2001, 40 circles out of 46 were observed. In 2002, a similar study was carried out in alternance (every two weeks) on two mountains belonging to the same Kongo-Ikoma mountain range, Mt Katsuragi and Mt Nijo (extinct volcano with 2 peaks separated by a saddle (431 m alt): Odake (517 m alt) and Medake (474 m alt)), for 75 days spanning three seasons from April 8 to October 16 (Figs 1, 2), On Mt Katsuragi, 22 circles out of 46 were checked while, on Mt Nijo, 26 circ]es were fixed and checked.