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Home , Acytolepis puspa, Badamia, Catochrysops, Catochrysops panormus, Catopsilia pyranthe, Megisba

98 PACIFIC SCIENCE . January 2005

Figure 1. Location of the .

along the shore. The average annual rainfall spp.) are the dominant trees on all but the ranges from about 363 cm in Chuuk (Merlin smallest islands, where coastal scrub and and Juvik 1996) to 1,015 cm estimated in the strand predominate. All of the islands fall mountains on (Merlin et al. 1992). within the equatorial rain belt and are wet The land area on the numerous, wide- enough to support a mesophytic vegetation spread, low (1–4 m high) coralline is (Mueller-Dombois and Fosberg 1998). All of miniscule. Satawan Atoll in the Mortlock the atolls visited during this survey are in- Islands, southern , has the largest habited or (in the case of Ant Atoll) have been total land area, with 4.6 km2 distributed so in the recent past. Ornamental shrubs, among approximately 49 islets (Bryan 1971). trees, and herbs are common in the settle- Houk (¼ Pulusuk Atoll), a lone islet west of ments, which are usually located on one or , is the largest single island several of the larger islets; the others are vis- (2.8 km2) among all of these outlyers. Coco- ited frequently to harvest coconuts, crabs, and nut (Cocos nucifera) and breadfruit (Artocarpus other forest products used by the community. Butterflies of the Eastern Caroline Islands . Buden et al. 99

materials and methods record from Kosrae, but this sight record re- quires confirmation.] Butterflies were collected by D.W.B. when the opportunity arose during biological sur- veys of several different taxonomic groups, Family including birds, reptiles, odonates, and milli- panormus (C. Felder) pedes, on Chuuk Lagoon islands (20 June–2 Ranges widely from and July 2003), Onoun Island, Namonuito Atoll through to eastern , and in (3–7 January 2003), Houk Island (26 De- the Pacific as far east as the Society Islands cember 2002–2 January 2003), Satawan Atoll (Tite 1959, Seki et al. 1991, Braby 2000). (17–26 December 2002, 7 July–1 August In , it has been recorded on Guam 2003), Pakin Atoll (7–9 August 2002, 5–7 (Parsons 1998) and Pohnpei (Buden and November 2003), Ant Atoll (28–31 March Miller 2003). During this study, C. panormus and 16–18 November 2001, and 10–11 May, was common on Nikalap Aru Island (Ant 7–8 September, and 6–9 November 2002), Atoll) and on Houk, Chuuk State. It was less Mokil Atoll (29 July–2 August 2002), Pinge- common on Onoun, Namonuito Atoll, where lap Atoll (29 March–1 April and 13–16 only one was collected and few others were December 2002), and Kosrae (20 June–6 seen. Nearly all were in coastal strand and July 2002). Specimens have been deposited forest edge where Canavalia sp. and Vigna in CSIRO Long Pocket Laboratory (In- marina vines were common. These are the dooroopilly, Australia) and The Natural His- first records from among the atolls of Micro- tory Museum (London). Sight records are nesia. enclosed in square brackets. Euchrysops cnejus (Fabricius) species accounts Ranges from India through Southeast Asia Family to New Guinea, Australia, and the western Pacific islands as far east as Fiji and Tonga. pomona (Fabricius) Schreiner and Nafus (1997) recorded it in the Ranges widely from Madagascar to the western Carolines in Palau and Yap. We re- , Vanuatu, and Fiji. It has port it from the eastern Carolines for the first been recorded in western Micronesia on time based on three previously unreported Palau and the Mariana Islands (Schreiner and specimens in the Bishop Museum: one from Nafus 1997), and Buden and Miller (2003) Dublon (¼ Tonoas) Island, Chuuk, and an- recorded it from Pohnpei in the eastern Car- other from Kusaie (¼ Kosrae), both collected olines. One collected at Utwa village and an- by Z. Ono in January 1936, and another from other along the Utwa-Walung road on 1 July Pohnpei collected by P. A. Adams in 1950. 2002, both apparently attracted to nearby , are the first reports from Kosrae. alata Jamides sp. (bochus group) Others were observed occasionally along More than 20 names have been proposed roadsides in different parts of the island dur- for the Jamides bochus species group in the ing 20 June–6 July. Pacific Islands, and the and species limits within this complex are unresolved. [Catopsilia pyranthe (Linnaeus)] Schreiner and Nafus (1997) recorded J. bochus [Ranges widely from Southeast Asia (Stoll) in Micronesia on Palau and Pohnpei. southward to Indo-Australia and to as far east No example of this group was found on as Fiji (W.J.T., unpubl. data). Schreiner and Pohnpei during a more recent survey (Buden Nafus (1997) recorded it in Micronesia in and Miller 2003). However, 28 collected Palau and Yap, and Buden and Miller (2003) during two different visits to Satawan Atoll recorded it on Pohnpei. One seen along the (December 2002, July 2003) are the first re- Utwa-Walung road on 1 July 2002 is the only ports for Chuuk State. They were in open, 100 PACIFIC SCIENCE . January 2005 weedy areas and nearly always on or in close and mode of its initial arrival and colonization proximity to the vine Vigna marina. of Kosrae (and elsewhere in the Pacific) is unknown, but the species is known to have Lampides boeticus (Linnaeus) spread across the whole of the Pacific from Ranges widely from Africa and Europe to about the 1840s (Vane-Wright 1993). It may the Orient, Hawai‘i, Indo-Australia, and the have reached Pohnpei via a ship from Ha- Pacific Islands as far east as Fiji and Tonga. wai‘i, as suggested by Scudder (1875), or as a Schreiner and Nafus (1997) recorded it in direct result of its migrating ability in track- Micronesia only as far east as Chuuk, but ing the spread of Asclepias (milkweed) host Sugarman (1979) recorded Lampides sp. from plants brought through trade (Vane-Wright in the , and 1993). Samuelson and Nishida (1987:165) referred One seen on Deke Island, Atoll, to this record as ‘‘probably L. boeticus.’’ Only on 30 March 2002 (D.W.B.) is the only rec- two were encountered during this survey: one ord for an eastern Carolines atoll. It flew collected on Tonoas, Chuuk Lagoon, on 27 among coastal shrubs and small trees on this June, and the other on Ta Island, Satawan uninhabited islet, alighting on the foliage Atoll, on 16 July 2003. briefly from time to time over several minutes before disappearing from view. No potential Zizula hylax (Fabricius) host plants were seen in the area. In all Widespread in the Pacific and previously probability it was a vagrant from one of two recorded in Micronesia as far east as Pohnpei adjacent high islands, Pohnpei (where it is (Buden and Miller 2003). Eight specimens now resident) or Kosrae (where it is pre- collected on Kosrae during this study are new sumed to be resident). island locality records, and three from Sata- wan are the first reported from an eastern Subfamily Nymphalinae Carolines atoll. Hypolimnas bolina (Linnaeus) Ranges widely from Madagascar to New Family Nymphalidae Zealand and numerous, small islands of the Subfamily Danainae Pacific, including all the high islands and Danaus plexippus (Linnaeus) many atolls of Micronesia (Schreiner and Ranges widely in tropical and temperate Nafus 1997). It has reached as far east as zones throughout the world, excluding Africa. Henderson and Pitcairn Islands and is often Schreiner and Nafus (1997) recorded it on the only butterfly species recorded from some nearly all major islands and island groups in remote Pacific islands. It was the most fre- Micronesia. Kosrae was not included in the quently encountered species during this study body of their work, although it was included, and was absent only from Pakin Atoll, where with an unexplained question mark, in a no butterflies were observed on two separate tabulated list. Aside from acknowledging a visits. It was usually seen in ruderal habitats, report from Pohnpei by Walker (1914), D. most often among species of Asteraceae. The plexippus was not reported from the Carolines records for and by Ackery and Vane-Wright (1984). The Atolls are based on specimens collected by Bishop Museum has two specimens from Dr. Nelson Esguerra in December 1987 and ‘‘Kusaie,’’ one collected by Z. Ono on 24 are a part of a small collection of at the January 1936 and another by H. K. Townes College of Micronesia Land Grant Office in on 19 August 1946. During this study, D. . Niering’s (1956:18) statement that plexippus was encountered regularly (up to ‘‘in the more open areas [on Kapingamarangi] four to five sightings per day) in the settle- a larger lepidopteran (butterfly) is relatively ments on Kosrae, mainly along the eastern common’’ probably also refers to this species. shore and on Lelu Island, which is connected The insects collected on Kapingamarangi to the main island by a causeway. The time during the expedition in which Niering par- Butterflies of the Eastern Caroline Islands . Buden et al. 101 ticipated were to have been deposited in the house & Lyell on Chuuk reported by usnm (Niering 1963), but none could be Schreiner and Nafus [1997] is not based on found in the museum collections, and there is misidentified material). Four of the lycaenids no evidence to indicate that the specimens (, Jamides sp. [bochus were ever deposited (R. Robbins, pers. group], Lampides sp., and Zizula hylax) and comm.). the nymphalid Hypolimnas bolina are the only resident or presumed resident species re- discussion corded on the atoll islands; a lone Monarch seen on Pingelap was probably a waif. The Of the 18 species of butterflies in five differ- lycaenids were most numerous in strand veg- ent families recorded in the eastern Caroline etation, especially among the legume vines Islands (Table 1), eight (44%) are Lycaenidae Vigna marina and Canavalia sp. The family (there are 19 species [nine lycaenids] if Nymphalidae is represented by five species in the occurrence of Catochrysops amasea Water- the eastern Carolines, the Pieridae by three,

TABLE 1 Butterfly Species Recorded from the Eastern Caroline Islands

Chuuk State Chuuk Atollsa Atollsb Lagoon Species Islands Nam Hou Sat Ant Nuk Kap Mok Pin Pohnpei Kosrae

Hesperiidae þ (Fabricius) Papilionidae Papilio xuthus (Linnaeus) þ Pieridae þþ* Catopsilia pyranthe þ SRc* (Linnaeus) þ þ Lycaenidae puspa (Horsfield) þ Catochrysops panormusd þ* þ* þ* þ* þ Euchrysops cnejus þ* þ* þ* Jamides sp. (bochus group) þ* þ Lampides boeticus þþ* Megisba strongyle Felder þ Zizina otis (Fabricius) þþ Zizula hylax þþ* þþ* Nymphalidae Danainae Danaus plexippus þ SRc* þþ* Nymphalinae Hypolimnas bolina þþ* þ* þ* þ* þ* þ* þ* þ* þþ Hypolimnas pithoeka Kirsh þþ Junonia villida (Fabricius) þþ Satyrinae Melanitis leda (Linnaeus) þþþ Sources: Schreiner and Nafus (1997) for Chuuk and Kosrae; Buden and Miller (2003) for Pohnpei. a Nam, Namonuito; Hou, Houk; Sat, Satawan. b Nuk, Nukuoro; Kap, Kapingamarangi; Mok, Mokil; Pin, Pingelap. c SR (sight record) only. d The report of C. amasea in the Caroline Islands by Schreiner and Nafus (1997) may be based in part or in whole on misidentified C. panormus, which was not listed in their work. In the absence of confirmed documentation, C. amasea is omitted from the list. * First report, this study. 102 PACIFIC SCIENCE . January 2005 and the Hesperiidae and Papilionidae by Arthur and Wilson 1967). However, the spe- one each. However, Papilio xuthus may be cies assemblage found in the Marshalls differs extirpated throughout its Micronesian range from that of the atolls of the eastern Caro- thus leaving papilionids currently unrepre- lines. Hypolimnas bolina is the only species sented (Schreiner and Nafus 1997). confirmed as common to both areas. Three All the species recorded in the eastern Marshall Islands species (Badamia exclama- Carolines are widely distributed among tionis, Danaus plexippus, and Junonia villida) the islands of Oceania and within the larger occur on one or more of the high islands of landmasses of Southeast Asia and Indo- the eastern Carolines but not on the atolls, Australia to the west, geographically the most and lycaenids, a major component of the likely sources for Micronesian populations. Caroline atolls fauna, are seemingly scarce Munroe (1996:276) considered the tropical in the Marshalls; none was recorded by Asian and Indo-Australian regions as the pri- Schreiner and Nafus (1997), although Sug- mary ‘‘ultimate sources of the lepidopteran arman (1979) recorded Lampides sp. on fauna for the vast Pacific area.’’ The Micro- Kwajalein. To what extent these geographic nesian islands exhibit progressive diminution differences in species assemblages and num- in butterfly species number eastward into the ber are real or a reflection of incomplete sur- more remote regions of the Pacific—43 in veys and sampling bias is uncertain. the western Carolines (Palau and Yap), at The apparent absence of butterflies on least 18 in the eastern Carolines (Chuuk, Pakin Atoll, Pohnpei State, on two different Pohnpei, Kosrae), and only five in the Mar- visits is unexpected and very likely an artifact shall Islands. Adler and Dudley (1994:159) of sampling. The flora of Pakin is typical of stated that ‘‘isolation generally is the most that of other low islands in this region, and important [geographic variable] in explaining the atoll is in close proximity to Pohnpei, butterfly species richness among tropical Pa- which has the largest number of butterfly cific islands,’’ and Munroe (1996:293) simi- species of any island in the eastern Carolines. larly regarded ‘‘the proximity to source of Rain and strong winds during much of the recruitment’’ as a particularly important fac- first visit doubtlessly contributed to the lack tor in determining the numbers of indigenous of records, though sunshine and windless pyraloid moth species in Micronesia. The conditions prevailed during the second. broad distribution of Micronesian butterflies, however, impedes assessment of patterns of acknowledgments origin and distribution for specific island groups such as the Carolines. Colonization Transportation to Pakin Atoll was provided may have been more complex than a pro- courtesy of the College of Micronesia Land gressive attenuation of species west to east Grant Pearl Oyster Project Team, and to Ant across ‘‘stepping-stone’’ islands into the more Atoll by Ray and Yenti Verg-in, aboard their distant areas of the Pacific. Regarding pyr- privately owned boat. We thank Bob Robbins aloid moths of the Carolines, for example, for his efforts in examining Smithsonian In- Munroe (1996:293) stated ‘‘Philippine, Mi- stitution records and collections in an attempt cronesian, and especially Papuan elements’’ to locate specimens that were to have been are important components of the Palauan deposited from a 1950s expedition to Ka- fauna, but ‘‘the picture is not so clear’’ for the pingamarangi Atoll, and we are grateful to Al FSM states, where ‘‘there are species of Mi- Samuelson for his prompt and detailed re- cronesian, Central Pacific, and Philippine sponses to our queries regarding specimens in derivation, but the majority are of indetermi- the Bishop Museum. nate origin.’’ The low number of species (five) for the Literature Cited Marshall Islands (all of which are atolls or low, single islets) is in large measure likely a Ackery, P. R., and R. I. Vane-Wright. 1984. combined distance/area effect (see, e.g., Mac- Milkweed butterflies: Their cladistics and Butterflies of the Eastern Caroline Islands . Buden et al. 103

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