A Review of the Systematics of Hawaiian Planthoppers (Hemiptera: Fulgoroidea)L

Pacific Science (1997), vol. 51, no. 4: 366-376 © 1997 by University of Hawai'i Press. All rights reserved A Review of the Systematics of Hawaiian Planthoppers (Hemiptera: Fulgoroidea)l MANFRED ASCHE2 ABSTRACT: With 206 endemic species, the phytophagous Fulgoroidea, or planthop pers, are among the most important elements of the native Hawaiian fauna. These principally monophagous or oligophagous insects occur in nearly all Hawaiian terrestrial ecosystems. Species of two of the 18 planthopper families occurring worldwide have successfully colonized and subsequently radiated in Hawai'i. Based on collections made mainly by Perkins, Kirkaldy, Muir, Giffard, and Swezey, more than 95% of these species were described in the first three decades of this century. The systematics of the Hawaiian planthoppers has changed little in the past 60 yr and is not based on any phylogenetic analyses. This paper attempts a preliminary phylogenetic evaluation ofthe native Hawaiian p1anthoppers on the basis ofcompara tive morphology to recognize monophyletic taxa and major evolutionary lines. The following taxa are each descendants of single colonizing species: in Cixiidae, the Hawaiian Oliarus and Iolania species; in De1phacidae, Aloha partim, Dictyophoro delphax, Emoloana, Leialoha + Nesothoe, Nesodryas, and at least four groups within Nesosydne. Polyphyletic taxa are the tribe "Alohini," Aloha s.l., Nesorestias, Nesosydne s.l., and Nothorestias. Non-Hawaiian species currently placed in Iolania, Oliarus, Aloha, Leialoha, and Nesosydne are not closely allied to the Hawaiian taxa. The origin of the Hawaiian planthoppers is obscure. The Hawaiian Oliorus appear to have affinities to (North) American taxa. ALTHOUGH THE HAWAIIAN ISLANDS are the most Other groups of Hawaiian insects have isolated islands on earth, they house a remark received far less attention, although they are ably rich flora and fauna. The more than 5000 speciose and ecologically, as well as behavior recorded native insect species are predominant ally, highly differentiated from each other. The components of the Hawaiian biota (see Nishida Hawaiian planthoppers (Fulgoroidea) represent 1994). This fauna is assumed to have derived one such neglected group. Although initially from only 400 primary colonizing species (How recorded from the Hawaiian Islands more than arth 1990). Several groups of Hawaiian insects 100 yr ago, little is known about their biology, have been studied in great detail (summarized ecology, and evolution. in Wagner and Funk 1995), such as the Drosoph Over 95% of the 206 currently recognized ilidae, which have been the focus of studies on native Hawaiian planthopper species were genetics, evolutionary biology, molecular evolu described in the first three decades of this cen tion, population ecology, and biogeography tury. The first phase ofplanthopper research was (e.g., Carson and Kaneshiro 1976, Kaneshiro based on the contributions of R. C. L. Perkins 1976, Carson and Templeton 1984, Carson 1987, and G. W. Kirkaldy. In the beginning of this DeSalle and Hunt 1987). century, Perkins was the first to collect substan tial numbers ofplanthoppers on all major Hawai I Manuscript accepted 3 February 1997. ian islands. He also made valuable observations 2 Research Associate in Entomology, Bernice P. Bishop on their ecology and distribution, which were Museum, Box 19000-A, Honolulu, Hawai'i 96817. Current later published in Fauna Hawaiiensis (Kirkaldy address: Museum fUr Naturkunde der Humboldt-Universitat zu Berlin, Institut ftir Systematische Zoologie, Invaliden 1902, 1910, Perkins 1913). Before his death in strasse 43, D-10115 Berlin, Germany. 1910, Kirkaldy had described 72 endemic 366 Systematics of Hawaiian Planthoppers-AscHE 367 Hawaiian planthopper species and established logenetic analysis ofthe Hawaiian planthoppers. seven genera (for complete references see Zim My review is an effort to reactivate systematic merman [1948]). research on this group and suggest future The second phase of Hawaiian planthopper research needs. research relied upon the important contributions of F. Muir and W. Giffard. Between 1916 and Review of the Hawaiian Planthoppers 1922, Muir described 82 new endemic species Although the Fulgoroidea are diverse and and one endemic genus of Delphacidae (e.g., speciose, with 18 families worldwide with over Muir 1916; further references in Zimmerman 15,000 species, only a small fraction reached [1948]). Soon after, Giffard revised the Hawai Hawai'i and then successfully colonized and ian Cixiidae, describing 44 new species and sub radiated there. Only the Cixiidae and the Delpha species (Giffard 1925). Zimmerman (1948) cidae are present in the native Hawaiian fauna. summarized these contributions in Insects of The Hawaiian species represent only 1.5% of Hawaii. Only seven endemic Hawaiian delpha all planthopper species, but about 95% of these cids (Swezey 1937, Zimmerman 1948, 1952, are endemic. The most comprehensive compila Beardsley 1956, 1960, Asche in press a) and tion of data on Hawaiian auchenorrhynchous two cixiids (Fennah 1973) have been described Homoptera was published by Zimmerman in the past 70 yr. (1948) in Insects of Hawaii, nearly 50 yr ago. The lack of scientific interest in the systemat The most recent listing is Nishida's (1994) ics and evolution of planthoppers is difficult to Hawaiian terrestrial arthropod checklist, where understand, particularly because these phytopha the following numbers are given: 88 endemic gous, sap-feeding insects are ubiquitous in taxa (63 species and 25 subspecies) of Cixiidae, nearly all Hawaiian terrestrial ecosystems. Most 145 endemic taxa (143 species, 2 subspecies) of native Hawaiian planthoppers have been Delphacidae, and 13 mostly adventive nonen reported as oligophagous or monophagus on demic planthopper species (i.e., Delphacidae [9 native Hawaiian plant species, mostly on ferns species; see also Beardsley (1990)], Flatidae [2 and woody dicots (see, e.g., Giffard 1917, 1922, species], and Derbidae [1 species]). Asche and Zimmerman 1948, Swezey 1954). In the native Wilson (1989a,b) reported an additional immi Hawaiian flora, over 70 plant genera with several grant delphacid species. In total, 219 planthop endemic species were reported as hosts ofplant per species and 26 subspecies have been reported hoppers, ranging from tree ferns (e.g., Cibotium, from Hawai 'i. The thirteen adventive species are Sadleria), native grasses (e.g., Eragrostis, Spo believed to have been introduced accidentally robolus, Vincentia), and palms (Pritchardia) to (e.g., Beardsley 1990); however, a few of them herbs including the endangered silverswords, may actually be indigenous because they are vines, shrubs, and trees (e.g., Argyroxiphium, widespread in the Pacific and on adjacent conti Dubautia, Freycinetia, Styphelia, Metrosideros, nents (e.g., the delphacids Sogatella kolophon Acacia) (e.g., Zimmerman 1948). Some of the (Kirkaldy), Opiconsiva paludum (Kirkaldy), and introduced planthopper species are important Toya dryope (Kirkaldy)). pests of crops in Hawai 'i, especially the Austral The actual number of species of Hawaiian asian delphacid Perkinsiella saccharicida planthoppers is unknown, because of unsolved Kirkaldy on sugarcane (see references in Zim taxonomic problems and the lack of a modern merman [1948]). survey. Most of the native species are known The current classification of Hawaiian plant only from a few specimens from the type local hoppers differs little from that employed by Zim ity, and several are known from the holotype merman (1948), who largely followed Kirkaldy only. (1910), Muir (1915), and Giffard (1925). The supraspecific taxa (genera, tribes) are based on diagnostic characters mostly used in keys. In the Family CIXIIDAE following, I survey the current state ofplanthop All 63 species and 25 subspecies of Hawaiian per systematics and propose a preliminary phy- Cixiidae are endemic: Oliarus with 58 species 368 PACIFIC SCIENCE, Volume 51, October 1997 and 24 subspecies from all Islands, and lolania My studies have shown that the Hawaiian with five species and one subspecies from all Oliarus species are not closely related to other major Islands except Moloka'i (Table 1). Two Pacific Cixiidae currently placed in Oliarus. Oliarus species are cavernicolous: both are trog This assumption is based on substantial morpho lobitic and were discovered by F. G. Howarth in logical differences mainly of the male and lava tubes on Maui and Hawai'i Island (Fennah female genitalia. Also, the Hawaiian species dif 1973). Hoch and Howarth (1993) mentioned at fer considerably in their morphology from the least four additional undescribed cave-dwelling type species of Oliarus, O. walkeri Stiil. Oliarus species, one from Moloka'i, two from According to the chaetotaxy of the posttarsi, the Maui, and one from Hawai'i Island. Hawaiian and most other Pacific taxa belong to the subtribe Pentastirina, whereas O. walkeri is in Oliarina. The Hawaiian Oliarus species are most likely Genus Oliarus monophyletic. This is based on synapomorphies The genus Oliarus must be regarded as poly in external characters such as the configuration phyletic because it is primarily based on the ofthe spines ofthe hind tarsi (first tarsal segment presence of five mesonotal carinae, a feature distally primarily with eight, second with seven that is likely plesiomorphic and present in all rigid spines) and male genital characters (e.g., members of the cixiid tribe Pentastirini. Despite the special arrangement

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