Hawaiian Lineages Research Articles

Genetic potential for changes in breeding systems: Predicted and observed trait changes during artificial selection for male and female allocation in a gynodioecious species.

Evolution of separate sexes from hermaphroditism often proceeds through gynodioecy, but genetic constraints on this process are poorly understood. Genetic (co-)variances and between-sex genetic correlations were used to predict evolutionary responses of multiple reproductive traits in a sexually dimorphic gynodioecious species, and predictions were compared with observed responses to artificial selection. Schiedea (Caryophyllaceae) is an endemic Hawaiian lineage with hermaphroditic, gynodioecious, subdioecious, and dioecious species. We measured genetic parameters of Schiedea salicaria and used them to predict evolutionary responses of 18 traits in hermaphrodites and females in response to artificial selection for increased male (stamen) biomass in hermaphrodites or increased female (carpel, capsule) biomass in females. Observed responses over two generations were compared with predictions in replicate lines of treatments and controls. In only two generations, both stamen biomass in hermaphrodites and female biomass in females responded markedly to direct selection, supporting a key assumption of models for evolution of dioecy. Other biomass traits, pollen and ovule numbers, and inflorescence characters important in wind pollination evolved indirectly in response to selection on sex allocation. Responses generally followed predictions from multivariate selection models, with some responses unexpectedly large due to increased genetic correlations as selection proceeded. Results illustrate the power of artificial selection and utility of multivariate selection models incorporating sex differences. They further indicate that pollen and ovule numbers and inflorescence architecture could evolve in response to selection on biomass allocation to male versus female function, producing complex changes in plant phenotype as separate sexes evolve.

Origin of Hawaiian ferns of the genus Ctenitis (Dryopteridaceae)

ABSTRACT The Hawaiian Islands are an emblematic field to study evolution, with their very high rates of endemism and spectacular cases of insular speciation. Nevertheless, many Hawaiian lineages still deserve investigation, such as in the fern lineage. In this study, we address the question of the origin of the fern genus Ctenitis, which is present in the archipelago with two endemic species, Ctenitis squamigera and C. latifrons. Using a taxonomic sampling covering the pantropical distribution of the genus and three chloroplast DNA regions, we provide evidence that the genus in the Hawaiian Islands originated from a single long-distance dispersal from the Neotropics. This area is less represented than Asia and the South Pacific in the origin of Hawaiian ferns, but a Neotropical origin may be explained by the transportation of spores by tropical storms originating near Central America. Furthermore, the colonization of the Hawaiian Islands is estimated to have occurred between 4 [9–2] and 3 [7–1] mya. This timing is consistent with the ages of all main and extant islands of the archipelago, which already provided habitats for the establishment of the initial Ctenitis colonizer. In turn, this relatively late arrival to the islands and the related potentially low availability of ecological niches may have hampered diversification of the genus beyond the two extant species.

Target enrichment improves phylogenetic resolution in the genus Zanthoxylum (Rutaceae) and indicates both incomplete lineage sorting and hybridization events.

Zanthoxylum is the only pantropical genus within Rutaceae, with a few species native to temperate eastern Asia and North America. Efforts using Sanger sequencing failed to resolve the backbone phylogeny of Zanthoxylum. In this study, we employed target-enrichment high-throughput sequencing to improve resolution. Gene trees were examined for concordance and sectional classifications of Zanthoxylum were evaluated. Off-target reads were investigated to identify putative single-copy markers for bait refinement, and low-copy markers for evidence of putative hybridization events. A custom bait set targeting 354 genes, with a median of 321 bp, was designed for Zanthoxylum and applied to 44 Zanthoxylum species and one Tetradium species as the outgroup. Illumina reads were processed via the HybPhyloMaker pipeline. Phylogenetic inferences were conducted using coalescent and maximum likelihood methods based on concatenated datasets. Concordance was assessed using quartet sampling. Additional phylogenetic analyses were performed on putative single and low-copy genes extracted from off-target reads. Four major clades are supported within Zanthoxylum: the African clade, the Z. asiaticum clade, the Asian-Pacific-Australian clade and the American-eastern Asian clade. While overall support has improved, regions of conflict are similar to those previously observed. Gene tree discordances indicate a hybridization event in the ancestor of the Hawaiian lineage, and incomplete lineage sorting in the American backbone. Off-target putative single-copy genes largely confirm on-target results, and putative low-copy genes provide additional evidence for hybridization in the Hawaiian lineage. Only two of the five sections of Zanthoxylum are resolved as monophyletic. Target enrichment is suitable for assessing phylogenetic relationships in Zanthoxylum. Our phylogenetic analyses reveal that current sectional classifications need revision. Quartet tree concordance indicates several instances of reticulate evolution. Off-target reads are proven useful to identify additional phylogenetically informative regions for bait refinement or gene tree based approaches.

RADseq resolves the phylogeny of Hawaiian Myrsine (Primulaceae) and provides evidence for hybridization

AbstractThe Hawaiian radiation of Myrsine (primrose family, Primulaceae) is the only one among the ten most species‐rich Hawaiian plant lineages that has never been included in a phylogenetic analysis. Our study is based on a RADseq dataset of nearly all Hawaiian Myrsine species and a Sanger sequencing dataset based on a worldwide sampling of Myrsine and related genera. Myrsine as a whole might be paraphyletic with respect to the monotypic Macaronesian genera Heberdenia and Pleiomeris, whereas Hawaiian Myrsine is resolved as monophyletic. The Sanger sequencing proved to be insufficient to resolve the Hawaiian lineage, whereas RADseq fully resolved the relationships with high support. Hawaiian Myrsine consists of three main lineages, of which one contains the majority of species and is mainly confined to Kauaʻi, and the other two lineages primarily consist of few widespread species. Although phylogenetic reconstructions delivered fully resolved and supported tree topologies, Quartet Sampling and HyDe analyses reveal phylogenetic incongruence throughout the phylogeny and provide the first molecular evidence of extensive hybridization in the lineage.

Colonization time on island settings: lessons from the Hawaiian and Canary Island floras

Abstract Molecular dating offers a tool for inferring the time of divergence between two lineages. In this study, we discuss how dated molecular reconstructions are informative of two different, albeit often intermingled, time estimates with regard to a fundamental process in island biogeography: the time of island colonization (TIC). We illustrate how stem age estimates provide information on the divergence between the extant island lineage and their closest relatives (i.e. the onset of lineage differentiation). Such estimates, however, are typically poor TIC predictors, as they are strongly affected by spatial and temporal uncertainty, particularly in cases of deep stem ages. Crown ages of endemic island lineages, in contrast, provide information on the temporal onset of island in situ diversification, and may represent a better proxy for TIC when the associated uncertainty is taken into account. Thus, the geographic and temporal distance separating the island and mainland lineages in phylogenetic/phylogeographic reconstructions are key factors for determining the reliability of these two estimates as proxies of TIC. We show how divergence times can be used to investigate the biogeographic patterns of two well-studied oceanic archipelagos: Hawaii and the Canary Islands. A compilation of molecular age estimates for nearly one-third of the endemic plant lineages in each archipelago reveals that Canarian plant lineages exhibit significantly younger mean crown ages (2.1 ± 2.4 Myr) than Hawaiian lineages (3.5 ± 2.9 Myr), despite island substrates being much older in the Canarian archipelago. We postulate that this pattern suggests: (1) a more important role of submerged islands during plant colonization in Hawaii, and (2) higher taxon turnover in the Canaries, mediated by relatively young (Mediterranean) lineages, and probably facilitated by the combination of the high incidence of extinction for the last 5 Myr and the close proximity of mainland source areas as compared to Hawaii.

Metapopulation Vicariance, Age of Island Taxa and Dispersal: A Case Study Using the Pacific Plant Genus Planchonella (Sapotaceae).

Oceanic islands originate from volcanism or tectonic activity without connections to continental landmasses, are colonized by organisms, and eventually vanish due to erosion and subsidence. Colonization of oceanic islands occurs through long-distance dispersals (LDDs) or metapopulation vicariance, the latter resulting in lineages being older than the islands they inhabit. If metapopulation vicariance is valid, island ages cannot be reliably used to provide maximum age constraints for molecular dating. We explore the relationships between the ages of members of a widespread plant genus (Planchonella, Sapotaceae) and their host islands across the Pacific to test various assumptions of dispersal and metapopulation vicariance. We sampled three nuclear DNA markers from 156 accessions representing some 100 Sapotaceae taxa, and analyzed these in BEAST with a relaxed clock to estimate divergence times and with a phylogeographic diffusion model to estimate range expansions over time. The phylogeny was calibrated with a secondary point (the root) and fossils from New Zealand. The dated phylogeny reveals that the ages of Planchonella species are, in most cases, consistent with the ages of the islands they inhabit. Planchonella is inferred to have originated in the Sahul Shelf region, to which it back-dispersed multiple times. Fiji has been an important source for range expansion in the Pacific for the past 23 myr. Our analyses reject metapopulation vicariance in all cases tested, including between oceanic islands, evolution of an endemic Fiji–Vanuatu flora, and westward rollback vicariance between Vanuatu and the Loyalty Islands. Repeated dispersal is the only mechanism able to explain the empirical data. The longest (8900 km) identified dispersal is between Palau in the Pacific and the Seychelles in the Indian Ocean, estimated at 2.2 Ma (0.4–4.8 Ma). The first split in a Hawaiian lineage (P. sandwicensis) matches the age of Necker Island (11.0 Ma), when its ancestor diverged into two species that are distinguished by purple and yellow fruits. Subsequent establishment across the Hawaiian archipelago supports, in part, progression rule colonization. In summary, we found no explanatory power in metapopulation vicariance and conclude that Planchonella has expanded its range across the Pacific by LDD. We contend that this will be seen in many other groups when analyzed in detail.

Chemical and genetic differences between Hawaiian lineages of the alga Asparagopsis taxiformis

Asparagopsis taxiformis is a widely distributed red alga, known locally in Hawai‘i as limu kohu. Over the past decade, it was discovered that A. taxiformis is a multiphyletic species, with analysis of mitochondrial DNA revealing several genetically distinct lineages present around the world. A. taxiformis samples from around O‘ahu, belonging to the three different lineages found in Hawaiian waters, were collected and subjected to parallel genetic and chemical profiling. Sequencing of the mitochondrial cytochrome oxidase I gene clearly separated the three lineages. In parallel, GC-MS profiling of the samples was conducted in order to determine whether there were any accompanying chemical differences. Analysis of the metabolite profiles using a range of multivariate statistical techniques showed that lineage 4 could be readily differentiated from the other two lineages, lineage 1 and lineage 2, by its chemical profile. Several halogenated metabolites characteristic of lineage 4 were also identified, including methyl bromoiodoacetate, methyl tribromoacetate, carbon tetrabromide, and dibromoacetone.

Phylogeny and biogeography of the pantropical genus Zanthoxylum and its closest relatives in the proto-Rutaceae group (Rutaceae)

Zanthoxylum L. (prickly ash) is the only genus in the Citrus L. family (Rutaceae) with a pantropical distribution. We present the first detailed phylogenetic and biogeographic study of the genus and its close relatives in the proto-Rutaceae group. Our phylogenetic analyses based on two plastid and two nuclear markers show that the genus Toddalia Juss. is nested within Zanthoxylum, that earlier generic and intrageneric classifications need revision, and that the homochlamydeous flowers of the temperate species of Zanthoxylum are the result of a reduction from heterochlamydeous flowers. The biogeographic analyses reveal a Eurasian origin of Zanthoxylum in the Paleocene or Eocene with successive intercontinental or long-range migrations. Zanthoxylum likely crossed the North Atlantic Land Bridges to colonize the Americas in the Eocene, and migrated back to the Old World probably via the Bering Land Bridge in the Oligocene or Miocene. Zanthoxylum also colonized several Pacific Islands and the Hawaiian clade shows phylogenetic incongruence between the plastid and nuclear datasets, suggesting hybridization. The Hawaiian species are one of the rare examples of endemic Hawaiian lineages that are older than the current main islands.

Historical biogeography of Melicope (Rutaceae) and its close relatives with a special emphasis on Pacific dispersals

AbstractThe genus Melicope (Rutaceae) occurs on most Pacific archipelagos and is perfectly suited to study Pacific biogeography. The main goal was to infer the age, geographic origin and colonization patterns of Melicope and its relatives. We sequenced three nuclear and two plastid markers for 332 specimens that represent 164 species in 16 genera of Rutaceae. Phylogenetic reconstruction, molecular dating, ancestral area reconstruction and diversification analyses were carried out. The two main clades (Acronychia‐Melicope and Euodia) originated in Australasia and their crown ages are dated to the Miocene. Diversification rates differed among the subclades and were lowest in the Euodia lineage and highest in the Hawaiian Melicope lineage. The Malagasy and Mascarene species form a clade, which split from its SE Asian relatives in the Pliocene/Pleistocene. At least eight colonizations to the Pacific islands occurred. The timing of all colonizations except for the Hawaiian group is congruent with age of the island ages. Australia, New Guinea and New Caledonia have been the source of colonizations into the Pacific islands in the Melicope clade. Melicope shows high dispersability and has colonized remote archipelagos such as the Austral and Marquesas Islands each twice. Colonization of islands of the Hawaiian‐Emperor seamount chain likely predates the ages of the current main islands, and the initial colonization to Kaua'i occurred after the splitting of the Hawaiian lineage into two subclades. Wider ecological niches and adaptations to bird‐dispersal likely account for the much higher species richness in the Acronychia‐Melicope clade compared to the Euodia clade.

Allometric Grip Strength Norms for Children of Hawaiian Lineage.

The purpose of the study was to determine allometric exponents for scaling grip strength in children that effectively control for body mass (BM) and stature (Ht) and to develop normative grip strength data for Hawaiian children. One thousand, four hundred thirty-seven students (754 boys) from a rural community in Hawaii participated in this 5-year study, resulting in 2,567 data points. Handgrip strength, BM, and Ht were collected every year. Multiple log-linear regression was used to determine allometric exponents for BM and Ht. Appropriateness of the allometric model was assessed through regression diagnostics, including normality of residuals and homoscedasticity. Allometrically scaled, ratio-scaled, and unscaled grip strength were then correlated with BM and Ht to examine the effectiveness of the procedure in controlling for body size. Allometric exponents for BM and Ht were calculated separately for each age group of boys and girls to satisfy the common exponent and group difference principles described by Vanderburgh. Unscaled grip strength had moderate to strong positive correlations with BM and Ht (p ≤ 0.05 for all) for all age groups. Ratio-scaled handgrip strength had significant moderate to strong negative correlations with BM (p ≤ 0.05 for all) and, to a lesser extent, Ht (p ≤ 0.05 for 8- to 12-year-old boys; p ≤ 0.05 for 8- to 12- and 14-year-old girls). Correlations between allometrically scaled handgrip strength and BM and Ht were not significant and approached zero. This study was the first to allometrically scale handgrip strength for BM and Ht in Hawaiian children. Allometric scaling applied to grip strength provides a useful expression of grip strength free of the confounding influence of body size.

Phytophthora colocasiae from Vietnam, China, Hawaii and Nepal: intra- and inter-genomic variations in ploidy and a long-lived, diploid Hawaiian lineage.

Phytophthora colocasiae is an important pathogen of taro and is widely distributed. Our goal was to develop whole genome sequence and single nucleotide polymorphism (SNP) markers to characterize historical and current populations from Hawaii (2010 and 2016, HA), historical isolates from Vietnam and China (2010, VN and CH) and current isolates from Nepal (2016, NEP). Seven isolates (VN = 2, CH = 1, HA = 1, NEP = 3) were sequenced (NCBI BioProject PRJNA378784) and compared using the reference genome of the closely related vegetable pathogen P. capsici. Genome-wide SNP analysis using 27,537 markers revealed genomes of diploid, triploid, tetraploid and higher ploidy. Ploidy varied within and between populations, with HA being primarily diploid, CH primarily triploid, VN containing diploid and triploid isolates, and NEP having predominantly triploid, tetraploid and higher ploidy. A total of 37 SNP markers were genotyped in 89 samples (grown in culture or directly from infected tissue) using targeted-sequencing. Analyses indicate a single clonal lineage dominated populations in HA from 2010 to 2016 and targeted-sequencing was useful to estimate ploidy. The implications for adaptation and evolution of P. colocasiae are discussed, as well as consequences for selection and breeding of resistant taro cultivars.

Kīkā Kila: How the Hawaiian Steel Guitar Changed the Sound of Modern Music

Kīkā Kila is a welcome addition to studies by academics on Hawaiian performance (including James Revell Carr's Hawaiian Music in Motion [2014] and Jim Tranquada and John King's The ‘Ukulele’ [2012]) and by dedicated amateurs (such as Lorene Ruymar's The Hawaiian Steel Guitar and Its Great Hawaiian Musicians [1996], and The Hula, by Jerry Hopkins et al. [1982]). The historian John W. Troutman chronicles a fascinating odyssey of the Hawaiian steel guitar set against the history of Hawaii and its uneasy relationship with America. The study presents a wide range of print sources, both on island and elsewhere, that Troutman complements with personal contacts with practitioners, notably Allan Akaka, a product of the second Hawaiian renaissance and descendant of a distinguished Hawaiian lineage. By the end of this absorbing and eminently readable account, readers have an understanding of the instrument as history, although they are less informed about the ways it “changed the sound of modern music” (emphasis added).

Chemical and genetic differences between Hawaiian lineages of the alga Asparagopsis taxiformis

Chemical and genetic differences between Hawaiian lineages of the alga Asparagopsis taxiformis

An enigmatic Hawaiian moth is a missing link in the adaptive radiation of Schiedea.

Shifts in pollination may drive adaptive diversification of reproductive systems within plant lineages. The monophyletic genus Schiedea is a Hawaiian lineage of 32 extant species, with spectacular diversity in reproductive systems. Biotic pollination is the presumed ancestral condition, but this key element of the life history and its role in shaping reproductive systems has remained undocumented. We observed floral visitors to two species of Schiedea and conducted field experiments to test pollinator effectiveness. We used choice tests to compare attraction of pollinators to species hypothesized to be biotically vs wind-pollinated. Pseudoschrankia brevipalpis (Erebidae), a recently described moth species known only from O'ahu, visited hermaphroditic Schiedea kaalae and S.hookeri and removed nectar from their unique tubular nectary extensions. Pseudoschrankia brevipalpis effectively pollinates S.kaalae; single visits to emasculated flowers resulted in pollen transfer. In choice tests, P.brevipalpis strongly preferred these hermaphroditic species over two subdioecious species capable of wind pollination. A shift from biotic to abiotic pollination is clearly implicated in the diversification of reproductive systems within Schiedea. Abundant pollination by a previously unknown native moth in experimental and restored populations suggests the potential for restoration to re-establish native plant-pollinator interactions critical for production of outcrossed individuals with high fitness.

Molecular Phylogeny, Revised Higher Classification, and Implications for Conservation of Endangered Hawaiian Leaf-Mining Moths (Lepidoptera: Gracillariidae: Philodoria)1

Abstract: The leaf-mining moth genus Philodoria Walsingham (Lepidoptera: Gracillariidae) is composed of 30 described species, all of which are endemic to the Hawaiian Islands. Philodoria is known to feed on 10 families of endemic Hawaiian host plants, with several species recorded only from threatened or endangered hosts. Beyond their dependence on these plants, little is known of their evolutionary history and conservation status. We constructed a molecular phylogeny of Philodoria to assess validity of its current subgeneric classification and to help guide future work on this threatened Hawaiian lineage. Mitochondrial and nuclear DNA sequences from three genes (CO1, CAD, EF-1α) combining for a total of 2,041 base pairs, were collected from 11 Philodoria species, incorporating taxa from both currently recognized subgenera. These data were analyzed using both parsimony and model-based phylogenetic approaches. Contrary to the most recent systematic treatment of Philodoria, our results indicate strongly tha...

Genomic signatures of geographic isolation and natural selection in coral reef fishes.

The drivers of speciation remain among the most controversial topics in evolutionary biology. Initially, Darwin emphasized natural selection as a primary mechanism of speciation, but the architects of the modern synthesis largely abandoned that view in favour of divergence by geographic isolation. The balance between selection and isolation is still at the forefront of the evolutionary debate, especially for the world's tropical oceans where biodiversity is high, but isolating barriers are few. Here, we identify the drivers of speciation in Pacific reef fishes of the genus Acanthurus by comparative genome scans of two peripheral populations that split from a large Central-West Pacific lineage at roughly the same time. Mitochondrial sequences indicate that populations in the Hawaiian Archipelago and the Marquesas Islands became isolated approximately 0.5Ma. The Hawaiian lineage is morphologically indistinguishable from the widespread Pacific form, but the Marquesan form is recognized as a distinct species that occupies an unusual tropical ecosystem characterized by upwelling, turbidity, temperature fluctuations, algal blooms and little coral cover. An analysis of 3737 SNPs reveals a strong signal of selection at the Marquesas, with 59 loci under disruptive selection including an opsin Rh2 locus. While both the Hawaiian and Marquesan populations indicate signals of drift, the former shows a weak signal of selection that is comparable with populations in the Central-West Pacific. This contrast between closely related lineages reveals one population diverging due primarily to geographic isolation and genetic drift, and the other achieving taxonomic species status under the influence of selection.

Distinct and extinct: Genetic differentiation of the Hawaiian eagle

Eagles currently occur in the Hawaiian Islands only as vagrants, but Quaternary bones of Haliaeetus eagles have been found on three of the major islands. A previous study of a ∼3500-year-old skeleton from Maui found its mtDNA more similar to White-tailed (H. albicilla) than to Bald (H. leucocephalus) Eagles, but low intraspecific resolution of the markers and lack of comparative data from mainland populations precluded assessment of whether the individual was part of the diversity found in Eurasia, or whether it represented an endemic Hawaiian lineage. Using ancient DNA techniques, we sequenced part of the rapidly evolving mtDNA control region from the same specimen, and compared it to published range-wide control region data from White-tailed Eagles and newly generated sequences from Bald Eagles. Phylogenetic analyses indicated that the Hawaiian eagle represents a distinct (>3% divergent) mtDNA lineage most closely related to those of extant White-tailed Eagles. Based on fossil calibration, we estimate that the Hawaiian mtDNA lineage diverged from mainland sequences around the Middle Pleistocene. Although not clearly differentiated morphologically from mainland forms, the Hawaiian eagle thus likely constituted an isolated, resident population in the Hawaiian archipelago for more than 100,000years, where it was the largest terrestrial predator.

Diversification in Hawaiian long-legged flies (Diptera: Dolichopodidae: Campsicnemus): Biogeographic isolation and ecological adaptation

Flies in the genus Campsicnemus have diversified into the second-largest adaptive radiation of Diptera in the Hawaiian Islands, with 179 Hawaiian endemic species currently described. Here we present the first phylogenetic analysis of Campsicnemus, with a focus on the Hawaiian fauna. We analyzed a combination of two nuclear (CAD, EF1α) and five mitochondrial (COI, COII, 12S, 16S, ND2) loci using Bayesian and maximum likelihood approaches to generate a phylogenetic hypothesis for the genus Campsicnemus. Our sampling included a total of 84 species (6 species from Europe, 1 from North America, 7 species from French Polynesia and 70 species from the Hawaiian Islands). The phylogenies were used to estimate divergence times, reconstruct biogeographic history, and infer ancestral ecological associations within this large genus. We found strong support for a South Pacific+Hawaiian clade, as well as for a monophyletic Hawaiian lineage. Divergence time estimates suggest that Hawaiian Islands were colonized approximately 4.6 million years ago, suggesting that most of the diversity within Campsicnemus evolved since the current high islands began forming ∼5 million years ago. We also observe a novel ecotype within the Pacific Campsicnemus; a widespread obligate water-skating form that has arisen multiple times across the Pacific Islands. Together, these analyses suggest that a combination of ecological, biogeographic and temporal factors have led to the impressive diversity of long-legged flies in Hawaii and elsewhere in the Pacific.

Diversity and phylogenetic relationships of Wolbachia in Drosophila and other native Hawaiian insects

Wolbachia is a genus of parasitic alphaproteobacteria found in arthropods and nematodes, and represents on of the most common, widespread endosymbionts known. Wolbachia affects a variety of reproductive functions in its host (e.g., male killing, cytoplasmic incompatibility, parthenogenesis), which have the potential to dramatically impact host evolution and species formation. Here, we present the first broad-scale study to screen natural populations of native Hawaiian insects for Wolbachia, focusing on the endemic Diptera. Results indicate that Wolbachia infects native Hawaiian taxa, with alleles spanning phylogenetic supergroups, A and B. The overall frequency of Wolbachia incidene in Hawaiian insects was 14%. The incidence of infection in native Hawaiian Diptera was 11% for individuals and 12% for all species screened. Wolbachia was not detected in two large, widespread Hawaiian dipteran families—Dolichopodidae (44 spp screened) and Limoniidae (12 spp screened). Incidence of infection within endemic Hawaiian lineages that carry Wolbachia was 18% in Drosophilidae species, 25% in Caliphoridae species, > 90% in Nesophrosyne species, 20% in Drosophila dasycnemia and 100% in Nesophrosyne craterigena. Twenty unique alleles were recovered in this study, of which 18 are newly recorded. Screening of endemic populations of D. dasycnemia across Hawaii Island revealed 4 unique alleles. Phylogenetic relationships and allele diversity provide evidence for horizontal transfer of Wolbachia among Hawaiian arthropod lineages.

Molecular phylogenetics of the moth genus Omiodes Guenée (Crambidae: Spilomelinae), and the origins of the Hawaiian lineage

The moth genus Omiodes (Crambidae) comprises about 80 species and has a circumtropical distribution, with the type species, O. humeralis, occurring in Central America. In Hawaii, there are 23 native species currently placed in Omiodes, but this classification has been disputed, and they were previously placed in various other genera. We used molecular phylogenetic analyses to assess the monophyly of Omiodes as a whole, and specifically of the Hawaiian species, as well as their geographic origins and possible ancestral host plants. Mitochondrial (COI) and nuclear (wingless, EF1α, CAD, and RPS5) DNA was sequenced for Omiodes from Hawaii, South America, and Australasia, along with many other putative outgroup spilomeline genera. Phylogenies were estimated using maximum likelihood and Bayesian inference, and various taxon and character datasets. With the exception of two paleotropical species (O. basalticalis and O. odontosticta, whose placement was unresolved) all Hawaiian, paleotropical and neotropical Omiodes, including the type species, fell within a well-supported, monophyletic clade. Although the center of diversity for Omiodes is in the Neotropics, its center of origin was ambiguous, due to poor resolution of the basal splits between paleotropical and neotropical Omiodes. Very low genetic divergence within the Hawaiian Omiodes suggests a relatively recent colonization of the Hawaiian Islands. Phylogenies constructed using all codon positions were poorly resolved at intergeneric levels, and did not reveal a sister taxon for Omiodes, but phylogenies constructed using only first and second codon positions suggested a close relationship with Cnaphalocrocis. The monophyly of several other spilomeline genera is also discussed.