Journal of Biogeography, 29, 655–662

Biogeography of on remote oceanic islands of the Pacific: archipelagoes as stepping stones? Rosemary G. Gillespie Division of Biology, University of California Berkeley, Berkeley, CA, USA

Abstract Aim The composition of species in any given island community may directly reflect the processes of immigration such that species on a more remote island comprise a nested subset of those on the nearest less remote land mass. Alternatively, new species can arise on islands by less frequent colonization but subsequent evolutionary differentiation. In the current study the species composition of spiders is examined in native communities on three remote oceanic archipelagoes to test hypotheses concerning the relative importance for species accumulation of (i) immigration from the nearest land mass, vs. (ii) in situ speciation. Location The study focuses on three volcanic hot-spot archipelagoes in the Pacific: the Hawaiian, Marquesas and Society Islands. Methods spiders were collected from the three remote Pacific archipelagoes as well as Australasia and America. Sequences of mitochondrial DNA (Cytochrome Oxidase I and 16S ribosomal DNA) were obtained from the spiders and a phylogenetic approach was used to examine relatedness among island endemic lineages of spiders, as well as associations between species on different archipelagoes with continental congeners. Results Within archipelagoes, species groups are largely monophyletic. When species groups are compared between archipelagoes, those on one archipelago are never the sister group to those on another archipelago. Rather, each archipelago has a mainland congener as its closest sister group. Main conclusions First, colonization of the Hawaiian, Marquesas and Society archipela- goes by Tetragnatha spiders appears to have occurred independently, most likely in each case from a continental source, but not from the nearest archipelago. Secondly, in situ speciation has occurred in the Marquesas and Society Islands in a similar manner to that in , although apparently on a smaller scale.

Keywords Spiders, Tetragnatha, Hawaii, Tahiti, Marquesas, phylogeny, evolution, adaptive radiation.

and extinction (MacArthur & Wilson, 1963, 1967), al- INTRODUCTION though the pattern may not be random (Whittaker, 1998). The nature of communities is fundamental to our under- Moreover, the composition of species on any island is standing of community ecology and evolutionary biology. generally considered to represent a subset of the species Of particular importance is how communities are formed, found on the nearest island that is larger and/or closer to a whether by immigration only, or by adaptive diversification source of colonists, a pattern termed ‘nestedness’ (Kadmon, from a few colonists (Schluter & Ricklefs, 1993). For 1995; Whittaker, 1998). In contrast, evolutionary studies on islands, ecological theory is largely based on the concept that remote islands have suggested that the composition of communities are formed as a consequence of immigration species on any island may be dictated largely by local adaptation, with single (or few) colonists proliferating to give rise to similar communities as a result of evolutionary Correspondence: University of California Berkeley, 201 Wellman Hall, convergence (Losos et al., 1998). Berkeley, CA 94720-3112, USA. E-mail: [email protected]

Ó 2002 Blackwell Science Ltd 656 R. G. Gillespie

The Pacific Ocean, the world’s largest water body, One of the most interesting findings from the Pacific contains about 25,000 islands, more than the total number Entomological Survey was that certain commonalities exist in the rest of the world’s oceans combined (Fig. 1). These in the faunas across different remote Polynesian islands display a broad spectrum of geographical attributes, archipelagoes, the basis for which was hotly debated in the with continental fragments, volcanic hot-spots, and atolls earlier part of the twentieth century (Adamson, 1939). The scattered across a huge range of isolation. Perhaps the best controversy focused on the existence, or lack thereof, of known Pacific archipelago is that of the Hawaiian Islands former land connections in the Pacific. J.W. Gregory which, because of its isolation and topographical diversity, (Gregory, 1930) espoused the view that there were extensive shows high levels of endemism for terrestrial organisms (c. land masses in the area currently occupied by the Pacific 90–98%), with numerous and spectacular examples of depression, which were submerged around the early tertiary, adaptive radiation (Gillespie et al., 2001). Some of the best the current fauna being relicts of the biota that arose on this examples of adaptive radiation in Hawaii come from large land mass. This view was based almost entirely on , as revealed by the classic studies on Drosophila biological evidence. For example, many of the mid-Pacific (Carson & Kaneshiro, 1976). More recent studies on a islands have endemic species of Lepidoptera in a small broad spectrum of arthropod lineages have led to new number of genera (Meyrick, 1935a,b): Asymphorodes insights into the uniqueness of the biota and patterns and (Cosmopterygidae), Dichelopa (Tortricidae), Scoparia and processes of evolution in the islands (Wagner & Funk, 1995; Mestolobes (Pyraustidae), and Ernophthora (Phycitidae). Liebherr & Polhemus, 1997; Roderick & Gillespie, 1998). That groups are apparently shared across the different The high island archipelagoes of the Societies and Mar- islands supported the idea that a large continent existed in quesas share much in common with the Hawaiian Islands, the central Pacific connecting islands from Rapa to the each archipelago having been formed from a drifting oceanic Marquesas, and the Societies to Pitcairn, with ancient hot spot resulting in a chain of islands arranged chronolo- connections to Hawaii. gically. In addition, the Societies and Marquesas form with A contrary view, represented in the work of H.E. Gregory Hawaii a continuum of extreme isolation, with the Hawai- (1928), was that the islands within the Pacific depression are ian chain the most isolated, the Societies the least (Gillespie of oceanic origin and acquired their faunas by overseas & Roderick, 2002), and each would have provided abun- dispersal. It is now well known that this is indeed the case: dant ecological opportunity for those colonists that were there were no land connections between the remote archi- successful. These circumstances have provided conditions for pelagoes of Polynesia. So how can we account for the adaptive radiation in the southern archipelagoes, as evi- apparent similarities of certain components of the faunas on denced by the results of the Pacific Entomological Survey in different island groups? One possibility that has been the 1930s (Adamson, 1939) and by more recent and advanced frequently is the use of intervening islands as extensive studies on snails (Murray et al., 1993; Johnson stepping-stones to more remote islands (Adamson, 1939), et al., 2000) and simuliid flies (Craig et al., 2001), with with similarities between islands explained by non-random observations on other groups in specific localities, such as colonization from one archipelago to the next. Another the weevils of Rapa (Paulay, 1985). hypothesis is that certain taxa tend to be dispersive by nature

100 120 140 160 180 160 140 120 100 80 60

40 40

Mexico Hawaii 20 20

Galapagos 0 0 PNG Solomons Marquesas

New Hebrides Samoa Society 20 20

South America Figure 1 Map of the Pacific Ocean showing 40 40 relative locations of archipelagoes and con- tinental areas from which taxa were collected 100 120 140 160 180 160 140 120 100 80 60 for the current study.

Ó 2002 Blackwell Science Ltd, Journal of Biogeography, 29, 655–662 Polynesian spiders 657 and such taxa might be expected to colonize remote islands, (Berland, 1934, 1942). However, expeditions in the year perhaps independently and/or repeatedly (Gillespie & 2000 revealed that the islands actually have a number of Roderick, 2002). endemic Tetragnatha in the high elevation forests (Gillespie, The current study compares patterns of immigration and in press a, b). The goals of the current study are: (1) to evolutionary change in a lineage of spiders in the long-jawed determine the relationship between lineages on different orb-weaving Tetragnatha in three remote island archipelagoes and test the hypothesis that these spiders archipelagoes and examines the hypothesis that less remote colonized via island stepping-stones; (2) to make a prelim- islands groups functioned as stepping-stones to those that inary assessment of the relative importance of immigration are more remote. Tetragnatha spiders are well known in vs. in situ diversification in species accumulation within continental areas, being widespread and conspicuous archipelagoes. although generally homogeneous in both morphology (elon- gate bodies and long legs) and ecology (orb web generally METHODS built over or near water) (Levi, 1981; Gillespie, 1987). However, the situation in the Hawaiian Islands represents a Collections paradox, with a large radiation of endemic species of Taxa studied here included representatives of the Tetragnatha, the diversity of which spans a tremendous genus Tetragnatha from (i) the Society Islands of Tahiti, spectrum of colours, shapes, sizes, ecological affinities and Moorea and Raiatea; (ii) the Marquesas Islands of Nuku behaviours (Gillespie & Croom, 1995; Gillespie et al., Hiva, Ua Huka and Hiva Oa; and (iii) the Hawaiian Islands 1997). Many species are web building, with striking of Kauai, Oahu, Lanai, Molokai, Maui and Hawaii. Also patterns, colours and structural modifications of the abdo- included were representative taxa that are widespread men that allow concealment within the specific microhabi- through the Pacific, and Australasian and American contin- tats that they occupy (Oxford & Gillespie, 2001). Some ental species. A total of twenty-seven representatives of the species have structural modifications of the cheliceral arma- genus (twenty-three species, two represented by three pop- ture, which allow specialization on specific prey types. One ulations each) were used in the study (see Appendix). entire clade of sixteen species (the ‘spiny leg’ clade) has Undescribed species were included in the analysis and are abandoned web building, with the concomitant development designated by a provisional species name in quotes, preceded of long spines along the legs and the adoption of an by the abbreviation ‘nsp’. These names are not to be taken as extremely vagile, cursorial predatory strategy (Gillespie, valid combinations nor species epithets; all are being 1991). This clade is monophyletic, and is closely related to described in a separate publication (Gillespie, in press a, b). the other lineages of web-building Hawaiian Tetragnatha (Gillespie et al., 1994, 1997). Within the clade, similar sets of species are found in most localities on all islands and DNA Sequences within a locality that can be characterized as ‘green; leaf- Two mitochondrial regions were sequenced: (i) Cytochrome dwelling’, ‘maroon; moss-dwelling’, and ‘gray/black; bark- oxidase subunit I (COI). A 768 bp region was amplified dwelling’. Initial studies based on morphological characters using primers LCO-1628 (ATAATGTAATTGTTACT- suggested that differentiation between species has never GCTCATGC), and HCO-2396 (ATTGTAGCTGAGGTAA- occurred on the same mountain mass: hypothesized sister AATAAGCTCG); (ii) 16S ribosomal DNA. A 508 bp region species were never found on the same volcano, or even on was amplified using primers A (CGCCTGTTTATCAAAAA- the same island (Gillespie, 1993). However, more recent CAT) and B2 (CTCCGGTTTGAACTCAGATCA) (12864– molecular information has shown a different pattern within 13417 in Drosophila) (Palumbi, 1996). The PCR reaction the spiny-leg clade; species on any one island are generally mix contained primers (0.48 M each), dNTPs (0.2 mM each) most closely related to each other and similar sets of and 0.6 U Perkin–Elmer (Foster City, California) AmpliTaqÒ ecological forms appear to have evolved independently on DNA polymerase (for a 50 lL reaction) with the supplied the different Hawaiian Islands (Gillespie et al., 1997). This buffer and, in some cases, with an extra amount of MgCl result therefore provides support for the importance of 2 (0.5–1.0 mM). The amplification profile used twenty-five evolution and adaptive radiation in community formation iterations of the following cycle: 30 s at 95 °C, 45 s at within an archipelago. 42–48 °C (depending on the primers) and 45 s at 72 °C, Given that adaptation and convergence have played a beginning with an additional single cycle of 2 min at 95 °C prominent role in the occupation of ecological space in genus and ending with another one of 10 min at 72 °C. PCR Tetragnatha in the Hawaiian Islands, the questions I results were visualized by means of an agarose/ TBE (1.8%) examine here are whether this same theme is found between gel. PCR products were cleaned using GenecleanÒ II (Bio and within the other remote archipelagoes of the Pacific and 101) or QIAGEN QIAquick PCR Purification Kits following whether the spiders have used less remote archipelagoes as the manufacturer’s specifications. DNA was sequenced stepping stones to those that are more remote. Knowledge of directly in both directions through the cycle sequencing the Tetragnatha fauna in the Pacific islands outside Hawaii is method using dye terminators (Sanger et al., 1977) and the limited and until recently the genus in the Society and ABI PRISM BigDyeTM (Applied Biosystems, Foster City, Marquesas islands was notable for its poor representation California) Terminator Cycle Sequencing Ready Reaction. compared with the large radiation in the Hawaiian Islands

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Sequenced products were cleaned using Princeton Separa- S nsp. “rava” tions CentriSep columns and run out on an ABI 377 100 O nsp. “tuamoaa” C automated sequencer. Sequence errors and ambiguities were I nsp. “moua” edited using the Sequencher 3.1.1 software package (Gene 100 E Codes Corporation, Ann Arbor, Michigan, USA). Manual T.nitens Moorea T 50 100 Y alignments took into account the secondary structure of 16S. T.nitens Indonesia Alignment of the protein coding COI was straightforward as 80 T.nitens Prto Rico M nsp. “punua” no length variation was observed in the sequences. For each 100 A species, two to five individuals were sequenced. Relation- nsp. “kapua” R Q. ships between taxa were examined using the consensus T.maxillosa Raiatea sequence for each species, with differences between indivi- 64 T.maxillosa Aus duals within species coded as a polymorphism. T.maxillosa Tahiti 51 T.tenuissima Phylogenetic methods 50 T.macilenta 58 T.valida Phylogenetic hypotheses were reconstructed using two meth- T.guatemalensis ods for the sequence data: (i) Maximum parsimony was used H 52 T. hawaiensis A as the optimality criterion. Branch support was assessed using T.laboriosa the bootstrap method with 200 pseudo-replicates and full W 88 nsp. “ lena” A heuristic searches. Characters were weighted (transversions: 67 T. albida I transitions) 2 : 1. Of 1200 total characters, 725 were 96 T. anuenue I T. obscura A constant, ninety-five were variable but parsimony-unin- N formative, and 380 were parsimony-informative. (ii) Dis- T.caudata tance was used as the optimality criterion (minimum T.straminea evolution) with maximum likelihood used as the distance 78 T.versicolor measure. Branch support was again assessed using the T.viridis bootstrap method with 200 pseudo-replicates and full heur- istic searches. Negative branch lengths were allowed, but set Figure 2 Phylogeny for representative mainland and island to zero for the tree-score calculation. Nucleotide frequencies Tetragnatha. Terminal taxa are all different species except for (empirical frequencies) used in the analysis were as follows: T. nitens (populations from , Indonesia and Moorea) and T. maxillosa (populations from Australia, Raiatea and Tahiti). A ¼ 0.290; C ¼ 0.151; G ¼ 0.166; T ¼ 0.393. All sites were Tetragnatha viridis was used as an outgroup, based on previous assumed to evolve at the same rate. These settings correspond analysis at deeper phylogenetic levels (Gillespie et al., 1994). Boxes to the Hasegawa–Kishino–Yano model (HKY) (Hasegawa represent the endemic species of the three different archipelagoes: et al., 1985). The transition/transversion ratio was estimated Societies, Marquesas (Marq.) and Hawaiian Islands. Other location based on maximum likelihood (estimated as 2.464166). abbreviations: Prto Rico, Puerto Rico; Aus, Australia. Branches with Starting tree(s) were obtained via neighbour-joining. bootstrap support of > 50% are shown at the nodes; all other branches have been collapsed. RESULTS analyses of 12S mtDNA (Gillespie et al., 1994). (ii) The For the range of genetic distances encompassing the major endemic taxa in the Marquesas Islands used in the current clades of Hawaiian, Marquesas and Society island Tetrag- study are monophyletic, with multiple species within the natha both transitions and transversions increased linearly archipelago. Examination of relationships among the Mar- when plotted against Tamura (1992) distance suggesting quesan taxa shows that these species have probably differ- that both transitions and transversions are phylogenetically entiated between islands, with multiple representatives now informative at this level and that the data, even at third co-occurring in certain localities (in particular, Nuku Hiva) positions, are not saturated (Gillespie et al., 1997). For (Fig. 3). (iii) The known endemic taxa in the Society Islands the greater distances between the representatives on different appear to stem from two independent origins. archipelagoes and on continents, transversions are still Examination of relationships between taxa on different informative, although transitions show evidence of archipelagoes shows that those found on each island group saturation. appear to have different origins. From the taxa included in Phylogenetic relationships among representatives from the the study, the group most closely related to the Tahitian different archipelagoes show the following (Fig. 2): (i) the endemic fauna is a weakly supported clade that includes endemic taxa in the Hawaiian Islands fall into three major T. maxillosa (from Australia and a likely recent introduction clades: the spiny leg clade, as represented by T. obscura and to much of the eastern Pacific), T. tenuissima (from the T. anuenue; the large web-building clade, represented by the Caribbean and ), T. macilenta (a wide- undescribed ‘Elongate Forest’ and T. albida, and the single spread Pacific species, possibly native to the Society Islands, species, T. hawaiensis, that occurs on all the Hawaiian but found no farther east) and T. valida (from Australia). Islands. This result agrees with similar results from previous The group most closely related to the Marquesan fauna

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T. marquesiana Nuku Hiva islands must have had some ancient connection (Meyrick, Nuku Hiva Ua Huka 1935a). We now know that this is not the case and that the nsp. “punua” three archipelagoes were formed independently as a result of 100 Ua Pou 79 Nuku Hiva Hiva Oa oceanic volcanism. An alternative explanation therefore is that the archipelagoes have served as ‘stepping stones’ from 64 nsp. “Uahuka” one to the other. This suggestion corresponds with the Ua Huka 100 concept of island biotas as nested subsets, such that species Fatu Hiva nsp. “kapua” composition on any one island represents a non-random Hiva Oa subset of the species found on the island ranked above it T. nitens Puerto Rico (Kadmon, 1995). Therefore, coarse examination of the presence of the same genus on all three isolated islands T. nitens Moorea might lead one to assume that its presence on one island archipelago is a function of its presence on the next less T. nitens Indonesia isolated archipelago, as has been documented for a range of taxa across the Pacific, including and marine organisms Figure 3 Phylogeny for all collected Marquesan Tetragnatha. was used as an outgroup. Branches with (Whittaker, 1998). bootstrap support of > 50% are shown at the nodes; all other However, the results of the phylogenetic analysis indicate branches have been collapsed. clearly that Tetragnatha on any of the three archipelagoes are unrelated to those on the other archipelagoes. Although appears to be the cosmotropical T. nitens (populations in we do not have full representation of the genus world-wide, this study included one from each of Indonesia, the Carib- we have sufficient evidence now to show that species on each bean island of Puerto Rico, and Moorea). Closest relatives to of the archipelagoes are more closely related to continental the Hawaiian taxa appear to be the mainland American and/or widespread circumtropical species, than they are to species T. laboriosa and T. caudata and possibly also representatives on the next less isolated island group. That T. pallescens (Gillespie et al., 1994). species on one archipelago did not give rise to those on other archipelagoes is not entirely surprising; it is well known that native taxa well represented on these islands tend to have DISCUSSION reduced dispersal abilities (Howarth & Mull, 1992). As in the Hawaiian Islands, Tetragnatha spiders are an Accordingly, the endemic species of one of these archipel- important component of the biota in the high elevation agoes may be unlikely colonizers of other archipelagoes forests of the islands of the Marquesas and Societies. (Gillespie & Roderick, 2002). Moreover, there are multiple species in any one locality in Yet, how is the similarity of taxa on the different remote the Marquesas and Societies, as in Hawaii, although (based archipelagoes explained? Ecological and behavioural studies on current information) the diversification seems to be much of continental Tetragnatha world-wide suggest that they less pronounced. The species in the Marquesas seem to be tend to be very effective at over-water dispersal as a result of monophyletic, while those in the Society Islands appear to their typical habitat over water and their ability to balloon represent at least two colonization events. The cosmotrop- (Okuma & Kisimoto, 1981). Aerial sampling has shown ical species T. nitens shows a very interesting pattern of that, although the genus is poorly represented among the phylogeography, with close affinities between populations spider plankton over continental land masses (Glick, 1939), from Puerto Rico and Indonesia and with the endemic in samples collected offshore (400 km from land in the Society Island species falling within the clade of T. nitens China Sea) Tetragnatha have been found to comprise 96% populations. It is not clear whether the populations of of the aerial spider plankton (Okuma & Kisimoto, 1981). T. nitens itself that occur at low elevations in the Societies This extraordinarily high representation of Tetragnatha over and Marquesas are indigenous. Tetragnatha macilenta is a the open sea suggests that the genus might be the most widespread Pacific species that may be indigenous to important of spiders in colonization of islands. Indeed, the the Society Islands, but is not found in the Marquesas. genus was found to be among the first and most persistent Tetragnatha macilenta is unrelated to the other Society colonists on mangrove islands in the Florida Bay (Simberloff Island taxa. Finally, T. maxillosa is widespread from & Wilson, 1968). Moreover, the finding that there have been Australasia through the Pacific, and is almost certainly a multiple colonizations of the Hawaiian Islands by repre- recent introduction to the Society Islands, with populations sentatives of this genus is also consistent with these from Raiatea, Tahiti and Australia showing virtually iden- observations (Gillespie et al., 1994). Therefore, based on tical DNA sequences. the results of the current study, it appears that representa- The current study is the first documentation of diversifi- tives of Tetragnatha from different continental origins have cation in Tetragnatha within the Marquesas and Society colonized each of the remote archipelagoes of the Societies, islands, the pattern of which appears to be analogous to that Marquesas and Hawaii. Once the spiders reached the in the Hawaiian Islands. The apparent similarity between islands, in each case they have formed endemic lineages, these archipelagoes is reminiscent of the earlier findings of the most diverse (based on current information) being those others that prompted the suggestion that these Polynesian in Hawaii. These endemic lineages have each diverged from

Ó 2002 Blackwell Science Ltd, Journal of Biogeography, 29, 655–662 660 R. G. Gillespie the ancestral riparian habitat, with their highest diversity in Gillespie, R.G. (in press a) Marquesan spiders of the genus the high elevation forests of the various islands. Concomit- Tetragnatha (Araneae: Tetragnathidae). Journal of Arachnol- antly, the spiders share a number of traits across islands, ogy. although the similarities appear to be entirely because of Gillespie, R.G. (in press b) Spiders of the genus Tetragnatha convergent evolution in similar environments. Independent (Araneae: Tetragnathidae) in the Society Islands. Journal of colonization of the different archipelagoes by Tetragnatha Arachnology. spiders has led to adaptive diversification in such a way as to Gillespie, R.G. & Croom, H.B. (1995) Comparison of speci- exploit the ecological opportunities presented on the differ- ation mechanisms in web-building and non-web-building ent archipelagoes in a similar manner. groups within a lineage of spiders. Hawaiian Biogeography: evolution on a hot spot archipelago (eds W.L. Wagner and V.A. Funk), pp. 121–146. Smithsonian Institution Press, ACKNOWLEDGMENTS . Gillespie, R.G. & Roderick, G.K. (2002) Arthropods on islands: I am most grateful to the organizers of the Insular Biotas colonization, speciation, and conservation. Annual Review of Conference for inviting me to the meeting in Wellington, Entomology., 47, 595–632. New Zealand. The work reported here was supported by Gillespie, R.G., Croom, H.B. & Palumbi, S.R. (1994) Multiple grants from the US National Science Foundation with origins of a spider radiation in Hawaii. Proceedings of the additional support from Evert Schlinger and the University National Academy of Sciences., 91, 2290–2294. of California, Berkeley. For help with collecting I am greatly Gillespie, R.G., Croom, H.B. & Hasty, G.L. (1997) Phyloge- indebted to the De´le´gation de la Re´cherche in Tahiti for netic relationships and adaptive shifts among major clades of allowing access to collecting sites in French Polynesia and in Tetragnatha spiders (Araneae: Tetragnathidae) in Hawai’i. particular to Jean-Yves Meyer for his tremendous assistance Pacific Science, 51, 380–394. with logistics and collecting. I owe thanks to many people Gillespie, R.G., Howarth, F.G. & Roderick, G.K. (2001) for help in the field: in French Polynesia, Teiki Richmond, Adaptive Radiation. Encyclopedia of biodiversity (ed. Ron Englund, Leo Shapiro and Miquel Arnedo; in Hawaii, S. Levin), pp. 25–44. Academic Press, New York. Art Medeiros and David Preston; in California, Cheryl Barr; Glick, P.A. (1939) The distribution of , spiders and mites in all localities, George Roderick. I would also like to in the air. Technical bulletin, No. 673, pp. 1–150. Depart- express thanks to Bob Edwards for sending me specimens of ment of Agriculture, Washington DC. Tetragnatha from the eastern USA and Greta Binford for Gregory, H.E. (1928) Types of Pacific islands. Proceedings of specimens from Indonesia. the Third Pan Pacific Science Congress, 2, 1662. Gregory, J.W. (1930) The geological history of the Pacific Ocean. Proceedings of the Geological Society, 86, 72–136. REFERENCES Hasegawa, M., Kishino, H. & Yano, T. (1985) Dating of the human-ape splitting by a molecular clock of mitochondrial Adamson, A.M. (1939) Review of the fauna of the Marquesas DNA. J. Mol. Evol., 22, 160–174. Islands and discussion of its origin. Bernice P. Bishop Howarth, F.G. & Mull, W.P. (1992) Hawaiian insects and their Museum Bulletin, 159, 1–93+i. kin. University of Hawaii Press, Honolulu. Berland, L. (1934) Araigne´es de Polyne´sie. Annales de la Socie`te` Johnson, M.S., Murray, J. & Clarke, B. 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Meyrick, E. (1935b) Pyrales and Microlepidoptera of the Society Tamura, K. (1992) Estimation of the number of nucleotide Islands. Bernice P. Bishop Museum Bulletin, 113, 109110. substitutions when there are strong transition-transversion Murray, J., Clark, B. & Johnson, M.S. (1993) Adaptive and G+C content biases. Molecular Biology and Evolution, 9, radiation and community structure of Partula on Moorea. 678–687. Proceedings of the Royal Society of London Series B Biology Wagner, W.L. & Funk, V.A. (1995) Hawaiian biogeography: Sciences, 254, 205–211. evolution on a hot spot archipelago. Smithsonian Institution Okuma, C. & Kisimoto, R. (1981) Airborne spiders collected Press, Washington, DC. over the East China Sea. (in Japanese). Japanese Journal of Whittaker, R.J. (1998) Island biogeography: ecology, evolution, Applied Entomology and Zoology, 25, 296–298. and conservation. Oxford University Press, Oxford. Oxford, G.S. & Gillespie, R.G. (2001) Portraits of evolution: studies of coloration in Hawaiian spiders. Bioscience, 51, 521–528. Palumbi, S.R. (1996) Nucleic acids II: the polymerase chain reaction. Molecular systematics (eds D. Hillis, C. Moritz and BIOSKETCH B. Mable), pp. 205–247. Sinauer Associates, Sunderland, MA. Paulay, G. (1985) Adaptive radiation on an isolated oceanic Rosemary Gillespie is Director of the Essig Museum of island: the Cryptorhynchinae (Curculionidae) of Rapa revis- Entomology and Professor in Insect Biology at the ited. Biological Journal of the Linnean Society, 26, 95–187. University of California at Berkeley where she holds the Roderick, G.K. & Gillespie, R.G. (1998) Speciation and William M and Esther G. Schlinger Chair in Systematic phylogeography of Hawaiian terrestrial arthropods. Molecu- Entomology. Her main research interests are the bioge- lar Ecology, 7, 519–531. ographical patterns and underlying ecological and evo- Sanger, F., Nicklen, S. & Coulsen, A.R. (1977) DNA sequencing lutionary processes that govern the formation of with chain terminating inhibitors. Proceedings of the populations, species and communities, on isolated land- National Academy of Sciences, 74, 5463–5468. masses. She has also published on conservation issues Schluter, D. & Ricklefs, R.E. (1993) Convergence and the affecting arthropods on islands. Most recently she has regional component of species diversity. Species diversity in been working on different populations and species of ecological communities: historical and geographical perspec- spiders to understand patterns of fragmentation, colon- tives (eds R.E. Ricklefs and D. Schluter), pp. 230–240. ization and the development of similar ecological forms, University of Chicago Press, Chicago. often with very different evolutionary histories, within Simberloff, D.S. & Wilson, E.O. (1968) Experimental zooge- and between island systems. ography of islands: the colonization of empty islands. Ecology, 50, 278–296.

Ó 2002 Blackwell Science Ltd, Journal of Biogeography, 29, 655–662 662 R. G. Gillespie

Appendix Table of collection localities for specimens used in the study. MAA, Miquel-Angel Arnedo; CBB, Cheryl B. Barr; GJB, Greta J. Binford; RLE, Robert L. Edwards; RE, Ron Englund; RGG, Rosemary G. Gillespie; ACM, Arthur C. Medeiros; DJP, David J. Preston; GKR, George K. Roderick; CWS, C.W. Senske; LS, Leo Shapiro

Island/country Species and state Location Elevation Date Collector

Society Islands nsp. ‘moua’ Tahiti Mt Aorai 1700 m 16 November 1999 RGG Mt Marau 1280 m 6 July 2000 RGG and MAA Tetragnatha macilenta Tahiti Mt Aori 1700 m 16 November 1999 RGG Moorea Belvedere 270 m 14 November 1999 RGG nsp. ‘rava’ Tahiti Mt Aori 580 m 19 November 1999 RGG Tahiti Tahiti Iti, Mt Teatara 650 m 7 July 2000 RGG nsp. ‘tuamoaa’ Moorea Vaiare–Paopao 540 m 3 July 2000 MAA Marquesas Islands Tetragnatha marquesiana Nuku Hiva Tovii Pass 1100 m 25 June 2000 RGG Nuku Hiva Mt Tekao 1185 m 23 June 2000 RGG and LS nsp. ‘punua’ Nuku Hiva Mt Tekao 1185 m 23 June 2000 RGG and LS nsp. ‘kapua’ Hiva Oa Temetiu Ridge 1170 m 28 June 2000 RGG nsp. ‘Uahuka’ Ua Huka Mt Hitikau 970 m 2 November 1999 RE Hawaiian Islands Tetragnatha albida East Maui Auwahi 1370 m 18 August 1997 RGG and ACM Tetragnatha anuenue Hawaii Island Kipuka 6, Saddle Road. 1700 m 30 September 1995 RGG and GKR Tetragnatha obscura Hawaii Island Kahaualea 670 m 18 March 1993 RGG and DJP nsp. ‘lena’ Oahu Tantalus 630 m 28 Aug 1993 RGG Tetragnatha hawaiensis Hawaii Island Thurston 1300 m 16 July 1997 RGG Widespread species that occur in Marquesas/Tahiti Tetragnatha nitens Puerto Rico Loquillo, El Verde Field Stn 300 m 14 March 1999 RLE Indonesia, Ujung Pondang, Fort 7 August 1994 GJB Rotterdam Moorea Gump Field Station 0 m 18 November 1999 RGG Tetragnatha maxillosa Australia N. Queensland, Cape 0 m 20 July 1992 RGG Tribulation Raiatea Temehani Plateau 800 m 12 July 2000 RGG Tahiti Papenoo Valley 195 m 7 July 2000 RGG Continental species USA, MA Salt Pond 9 April 1998 RLE Tetragnatha guatemalensis USA, PA Quakertown, Lake 25 August 1998 CWS Nockamixon, Bucks Co USA, MA Barnstable Co., Hatchville 10 June 1999 RLE USA, MA Barnstable Co., Hatchville 10 June 1999 RLE Tetragnatha tenuissima Puerto Rico Luquillo, El Verde 300 m 14 March 1999 RLE Field Station Tetragnatha valida Australia, N. Mossman-Daintree National 100 m 23 July 1992 RGG Queensland Park USA, CA Santa Cruz Is. Spr. E. La Cen- 3 May 2000 CBB tinela Tetragnatha viridis USA, MA Barnstable Co., Hatchville 9 March 1998 RLE

Ó 2002 Blackwell Science Ltd, Journal of Biogeography, 29, 655–662