Search

Abstract: The Veronicellidae include some of the most widespread and agriculturally damaging invasive slugs. However, they are difficult to distinguish and identify accurately based on external morphology because of their [...]

Hawaii, despite being only about 0.2% of the land mass of the continental United States, accounts for nearly half of all endangered species listed under the Endangered Species Act. Among the most prominent threats to biodiversity, including climate change and habitat destruction, impacts from invasive species are among the most notable. Each year dozens of novel plant and animal species are introduced and establish in Hawaii, and it is likely that many more go undetected. Those that establish and spread negatively impact the nearly 10,000 endemic species that evolved in isolation over millions of years. This process of rapid extinction of native species and replacement with globally distributed generalists is homogenizing Hawaii's unique fauna, causing the islands' biota to resemble more and more that of any other warm rocks in the ocean. The loss of biodiversity extends beyond species loss, and with each extinction, we are losing the stories and connections we have with the land through our shared evolutionary history, connections on which the hope to preserve the distinctive culture and ways of living in Hawaii, and globally, depend. Here we report the case of two newly recorded invasive snail species, Otala lactea and Zachrysia provisoria, and emphasize the necessity of formalizing and broadening partnerships to help stem the tide of invasive species and help conserve the valuable natural and biocultural resources on which island life relies. Hawaii, like many oceanic islands, serves as a microcosm for processes impacting the entire world. The lessons learned, and practices applied here can help develop prevention and management policies and actions that can be scaled up to stem biodiversity loss globally. [ABSTRACT FROM AUTHOR]

The Hawaiian archipelago was formerly home to one of the most species-rich land snail faunas (> 752 species), with levels of endemism > 99%. Many native Hawaiian land snail species are now extinct, and the remaining fauna is vulnerable. Unfortunately, lack of information on critical habitat requirements for Hawaiian land snails limits the development of effective conservation strategies. The purpose of this study was to examine the plant host preferences of native arboreal land snails in Puʻu Kukui Watershed, West Maui, Hawaiʻi, and compare these patterns to those from similar studies on the islands of Oʻahu and Hawaiʻi. Concordant with studies on other islands, we found that four species from three diverse families of snails in Puʻu Kukui Watershed had preferences for a few species of understorey plants. These were not the most abundant canopy or mid canopy species, indicating that forests without key understorey plants may not support the few remaining lineages of native snails. Preference for Broussaisia arguta among various island endemic snails across all studies indicates that this species is important for restoration to improve snail habitat. As studies examining host plant preferences are often incongruent with studies examining snail feeding, we suggest that we are in the infancy of defining what constitutes critical habitat for most Hawaiian arboreal snails. However, our results indicate that preserving diverse native plant assemblages, particularly understorey plant species, which facilitate key interactions, is critical to the goal of conserving the remaining threatened snail fauna. [ABSTRACT FROM AUTHOR]

The Veronicellidae include some of the most widespread and agriculturally damaging invasive slugs. However, they are difficult to distinguish and identify accurately based on external morphology because of their great intraspecific variability, especially in body color and pigmentation pattern. Based on the published accounts, museum collections, and recent surveys, four species had been recorded previously from the Hawaiian Islands: Diplosolenodes occidentalis, Laevicaulis alte, Sarasinula plebeia, and Veronicella cubensis; and the latter three plus an additional species, Semperula wallacei, were known from the Samoan Islands. We reexamined these identifications using external morphology, internal anatomy, and/or DNA sequences. Both L. alte and V. cubensis are present on all six of the largest Hawaiian Islands. Sarasinula plebeia, although recorded previously, was not present in the museum collections and was found in only one of our recent survey samples, on O'ahu. It may in fact never have been present in the Islands previously, the earlier records being misidentifications; or it may have been present but highly localized and was not collected and deposited in the Bishop Museum (Honolulu). Unfortunately, the single Diplosolenodes occidentalis specimen was not found in the usnm collections. Molecular analyses of specimens from American Samoa, previously identified as L. alte and S. plebeia, showed them to be primarily V. cubensis, with a few Semperula wallacei and Laevicaulis sp., and a single L. alte and S. plebeia, and all specimens sequenced from independent Samoa were S. wallacei. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Eosinophilic meningitis caused by infection with Angiostrongylus cantonensis, a parasitic nematode, is an emerging infectious disease of humans and other animals, known as angiostrongyliasis or rat lungworm disease. Symptoms range from headache and muscle spasms in mild cases to coma and even death. Many human cases have been recorded around the world, with the majority in tropical and subtropical locations. The increase in numbers of human cases and the expansion of the geographic distribution of cases make this parasite and its hosts important research foci. Definitive hosts include various rat species such as Rattus norvegicus, R. rattus, and R. exulans, and a number of land and freshwater snails and slugs have previously been identified as intermediate hosts. Both definitive and intermediate hosts are obligate to the life cycle of A. cantonensis. Paratenic hosts span a wide range of fauna and are not needed in the nematode's life cycle, but act as reservoirs in which different larval stages of the parasite can persist but not develop further; they include freshwater shrimp, flatworms, and frogs. Accidental hosts, including humans and other mammals, as well as birds, permit development from the third larval stage to the subadult (fifth) stage but are then dead ends for the parasite. These hosts are infected primarily through consumption of raw or undercooked intermediate or paratenic hosts, either intentionally or accidentally via contaminated produce. In Hawai'i, there have been recent outbreaks with cases of infection on four of the main islands. Since there is currently a limited consensus on appropriate therapy, steps to prevent infection should be taken. The first step to facilitate this and to lay the groundwork for future management of the hosts is to identify the intermediate hosts of A. cantonensis and to determine its geographic distribution within the Hawaiian Islands. To do this over 1000 specimens of 37 terrestrial and freshwater snail and slug species (30 introduced, 7 native) from the six largest Hawaiian Islands were screened using a molecular approach. 8 Total DNA was extracted from foot tissue of each specimen and was amplified using Angiostrongylus-specific primers. Amplicons were visualized on agarose gels to determine if specimens were positive or negative for A. cantonensis. All of the positive specimens and a random sample of all other specimens tested were also reamplified using species-specific primers. All positive samples were still positive with the newer primers. The parasite was present in 16 (14 alien, 2 native) of these species, from five of the six largest Hawaiian Islands. These species represent 10 phylogenetically diverse terrestrial pulmonate families and 2 more distantly related caenogastropod families (one terrestrial and one freshwater). This broad phylogenetic representation demonstrates that this parasite is not host specific, to the extent that perhaps even any snail or slug species could act as an intermediate host. [ABSTRACT FROM AUTHOR]