Eosinophilic meningitis caused by the parasitic nematode Angiostrongylus cantonensis is an emerging infectious disease with recent outbreaks primarily in tropical and subtropical locations around the world, including Hawaii. Humans contract the disease primarily through ingestion of infected gastropods, the intermediate hosts of Angiostrongylus cantonensis. Effective prevention of the disease and control of the spread of the parasite require a thorough understanding of the parasite's hosts, including their distributions, as well as the human and environmental factors that contribute to transmission. The aim of this study was to screen a large cross section of gastropod species throughout the main Hawaiian Islands to determine which act as hosts of Angiostrongylus cantonensis and to assess the parasite loads in these species. Molecular screening of 7 native and 30 non-native gastropod species revealed the presence of the parasite in 16 species (2 native, 14 non-native). Four of the species tested are newly recorded hosts, two species introduced to Hawaii (Oxychilus alliarius, Cyclotropis sp.) and two native species (Philonesia sp., Tornatellides sp.). Those species testing positive were from a wide diversity of heterobranch taxa as well as two distantly related caenogastropod taxa. Review of the global literature showed that many gastropod species from 34 additional families can also act as hosts. There was a wide range of parasite loads among and within species, with an estimated maximum of 2.8 million larvae in one individual of Laevicaulis alte. This knowledge of the intermediate host range of Angiostrongylus cantonensis and the range of parasite loads will permit more focused efforts to detect, monitor and control the most important hosts, thereby improving disease prevention in Hawaii as well as globally.

The International Union for Conservation of Nature (IUCN) Red List includes 832 species listed as extinct since 1600, a minuscule fraction of total biodiversity. This extinction rate is of the same order of magnitude as the background rate and has been used to downplay the biodiversity crisis. Invertebrates comprise 99% of biodiversity, yet the status of a negligible number has been assessed. We assessed extinction in the Hawaiian land snail family Amastridae (325 species, IUCN lists 33 as extinct). We did not use the stringent IUCN criteria, by which most invertebrates would be considered data deficient, but a more realistic approach comparing historical collections with modern surveys and expert knowledge. Of the 325 Amastridae species, 43 were originally described as fossil or subfossil and were assumed to be extinct. Of the remaining 282, we evaluated 88 as extinct and 15 as extant and determined that 179 species had insufficient evidence of extinction (though most are probably extinct). Results of statistical assessment of extinction probabilities were consistent with our expert evaluations of levels of extinction. Modeling various extinction scenarios yielded extinction rates of 0.4-14.0% of the amastrid fauna per decade. The true rate of amastrid extinction has not been constant; generally, it has increased over time. We estimated a realistic average extinction rate as approximately 5%/decade since the first half of the nineteenth century. In general, oceanic island biotas are especially susceptible to extinction and global rate generalizations do not reflect this. Our approach could be used for other invertebrates, especially those with restricted ranges (e.g., islands), and such an approach may be the only way to evaluate invertebrates rapidly enough to keep up with ongoing extinction.

Angiostrongylus cantonensis (rat lungworm), a parasitic nematode, is expanding its distribution. Human infection, known as angiostrongyliasis, may manifest as eosinophilic meningitis, an emerging infectious disease. The range and incidence of this disease are expanding throughout the tropics and subtropics. Recently, the Hawaiian Islands have experienced an increase in reported cases. This study addresses factors affecting the parasite's distribution and projects its potential future distribution, using Hawaii as a model for its global expansion. Specimens of 37 snail species from the Hawaiian Islands were screened for the parasite using PCR. It was present on five of the six largest islands. The data were used to generate habitat suitability models for A. cantonensis, based on temperature and precipitation, to predict its potential further spread within the archipelago. The best current climate model predicted suitable habitat on all islands, with greater suitability in regions with higher precipitation and temperatures. Projections under climate change (to 2100) indicated increased suitability in regions with estimated increased precipitation and temperatures, suitable habitat occurring increasingly at higher elevations. Analogously, climate change could facilitate the spread of A. cantonensis from its current tropical/subtropical range into more temperate regions of the world, as is beginning to be seen in the continental USA.

The elepaio (Chasiempis sandwichensis) is a monarch flycatcher endemic to the Hawaiian Islands of Kauai, Oahu, and Hawaii. Elepaio vary in morphology among and within islands, and five subspecies are currently recognized. We investigated phylogeography of elepaio using mitochondrial (ND2) and nuclear (LDH) markers and population structure within Hawaii using ND2 and microsatellites. Phylogenetic analyses revealed elepaio on each island formed reciprocally monophyletic groups, with Kauai ancestral to other elepaio. Sequence divergence in ND2 among islands (3.02-2.21%) was similar to that in other avian sibling species. Estimation of divergence times using relaxed molecular clock models indicated elepaio colonized Kauai 2.33 million years ago (95% CI 0.92-3.87 myr), Oahu 0.69 (0.29-1.19) myr ago, and Hawaii 0.49 (0.21-0.84) myr ago. LDH showed less variation than ND2 and was not phylogenetically informative. Analysis of molecular variance within Hawaii showed structure at ND2 (fixation index = 0.31), but microsatellites showed no population structure. Genetic, morphological, and behavioral evidence supports splitting elepaio into three species, one on each island, but does not support recognition of subspecies within Hawaii or other islands. Morphological variation in elepaio has evolved at small geographic scales within islands due to short dispersal distances and steep climatic gradients. Divergence has been limited by lack of dispersal barriers in the extensive forest that once covered each island, but anthropogenic habitat fragmentation and declines in elepaio population size are likely to decrease gene flow and accelerate differentiation, especially on Oahu.

Aim Morphological and taxonomic diversity are intuitive measures of biological diversity. Previous studies have shown discordance between these measures at large spatial and temporal scales, but the implications of this pattern for the underlying processes are not understood. Using oceanic archipelagos as spatial units, we examine potential links between the morphological and taxonomic diversity of their land snail faunas in a biogeographical framework.Location Eleven major oceanic archipelagos.Methods For each archipelago, we assembled lists of indigenous land snail species, classified by family and genus, with shell height and width for each species (1723 species in total). We used biogeographic and climatic variables as potential predictors of diversity patterns. We employed regression analyses to evaluate (1) whether morphological diversity scales with taxonomic diversity at the species, genus or family level, and (2) whether morphological and taxonomic diversity correlate similarly with biogeographic/climatic factors. We also assessed which taxonomic level contributes most to morphological variation within archipelagos.Results Morphological diversity across archipelagos was strongly related to genus but not species richness. Within archipelagos, morphological variation reflected differences among genera and families but not species. Species richness was best explained by archipelago area, but morphological diversity was not significantly related to any of the physical features of archipelagos.Main conclusions Across archipelagos, species richness and morphological diversity of land snail faunas are decoupled. The relationship between species richness and the available ecological space (captured mainly by area) indicates the prevalence of niche-based processes while, for morphological diversity, the strong conservatism of morphology at the genus level suggests the presence of diversification-based limits. Assuming genera effectively reflect diversification, our findings indicate that morphological space on oceanic archipelagos depends primarily on the number of evolutionary units that have colonized and/or diversified through time.

To test the validity of subspecies designations of the white tern, genetic and morphological data were used to assess differences among four putative Pacific subspecies Gygis alba candida, Gygis alba rothschildi, Gygis alba pacifica, and Gygis alba microrhyncha. The origin(s) of a recent colonization of Oahu was also examined using molecular data. Samples were collected from 209 birds, representing island groups of the North and South Pacific. Culmen length and depth, longest and shortest rectrix lengths, and wing chord measurements from an earlier dataset were compared. Mitochondrial DNA variation suggests that there are no phylogenetically distinct species within the Pacific Ocean. The genetic and morphological similarity of G. a. candida and G. a. rothschildi warrants merging them into one subspecies (G. a. candida). Gygis alba microrhyncha and G. a. pacifica are distinctly smaller and larger than the other two subspecies, respectively, but are not completely diagnosable across the morphological characters examined. Although the Pacific subspecies do not exhibit reciprocal monophyly, there is significant genetic differentiation among the two South Pacific groups, G. a. microrhyncha, G. a. pacifica, and all other Pacific subspecies. This differentiation warrants treating these two South Pacific groups as separate management units, but not species or subspecies. Finally, the recently established population of white terns on Oahu shared haplotypes with all subspecies, suggesting multiple origins from populations across the Pacific and confirming contemporary gene flow.

Since 1955 snails of the Euglandina rosea species complex and Platydemus manokwari flatworms were widely introduced in attempted biological control of giant African snails (Lissachatina fulica) but have been implicated in the mass extinction of Pacific island snails. We review the histories of the 60 introductions and their impacts on L. fulica and native snails. Since 1993 there have been unofficial releases of Euglandina within island groups. Only three official P. manokwari releases took place, but new populations are being recorded at an increasing rate, probably because of accidental introduction. Claims that these predators controlled L. fulica cannot be substantiated; in some cases pest snail declines coincided with predator arrival but concomitant declines occurred elsewhere in the absence of the predator and the declines in some cases were only temporary. In the Hawaiian Islands, although there had been some earlier declines of native snails, the Euglandina impacts on native snails are clear with rapid decline of many endemic Hawaiian Achatinellinae following predator arrival. In the Society Islands, Partulidae tree snail populations remained stable until Euglandina introduction, when declines were extremely rapid with an exact correspondence between predator arrival and tree snail decline. Platydemus manokwari invasion coincides with native snail declines on some islands, notably the Ogasawara Islands of Japan, and its invasion of Florida has led to mass mortality of Liguus spp. tree snails. We conclude that Euglandina and P. manokwari are not effective biocontrol agents, but do have major negative effects on native snail faunas. These predatory snails and flatworms are generalist predators and as such are not suitable for biological control.

Pacific islands, with their incredible biodiversity, are our finest natural laboratories for evolutionary, ecological and cultural studies. Nowhere, in relation to land area, does land snail diversity reach that of the Pacific islands, with more than 6,000 species, most of which are single island endemics. Unfortunately, land snails are the most imperiled group with the most recorded extinctions since the 1500s, and Pacific island snails make up the majority of those extinctions. In 1990, Dr. Alan Solem, a well renowned malacologist, with expertise in Pacific island land snails, posthumously published a plea to save the remaining Hawaiian land snails before they vanish forever. Now, more than 25 years later, we have finally begun to make inroads into answering the questions "How many Hawaiian land snails remain?" and "What will we need to save them?". Here we provide a belated reply to Solem (1990) and address these questions about Hawaiian land snails. We conclude by building on the actions suggested by Solem and that we feel are still needed to realize his hope of conserving Hawaii's remaining land snails specifically, but also our hope of conserving invertebrates more broadly.