Negative impacts of invasive predators used as biological control agents against the pest snail Lissachatina fulica: the snail Euglandina ‘rosea’ and the flatworm Platydemus manokwari

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

The rat lungworm, Angiostrongylus cantonensis : intermediate hosts and distribution in Hawaiʻi

M.S. University of Hawaii at Manoa 2013.Includes bibliographical references.Eosinophilic meningitis caused by the parasitic nematode Angiostrongylus cantonensis is an emerging infectious disease in tropical/subtropical locations. Humans contract it through ingestion of infected gastropods, the intermediate hosts of A. cantonensis, rats being the definitive hosts. The goal of this thesis is to better understand the host range and geographic distribution of the parasite in Hawaii by: 1) identifying the gastropod species that act as hosts and assessing their parasite loads; 2) ascertaining the distribution of A. cantonensis, modeling the environmental factors influencing it, and predicting habitat suitability throughout Hawaii. Numerous gastropod species (16 of 37 screened) tested positive for A. cantonensis, with a large range of parasite load among and within species. The parasite occurs on five of the six largest islands (not Lanai). A habitat suitability model using mean annual temperature and rainfall predicted that windward areas (higher rainfall) and lower elevations (higher temperatures) were most suitable

New Records of Alien Gastropoda in the Hawaiian Islands: 1996–2010

The alien nonmarine gastropods of the Hawaiian islands were cataloged by Cowie (1997) and were reviewed by Cowie (1998a). Subsequent new records (both for the archipelago and for individual islands) were reported by Cowie (1998b, 1999, 2000), Kraus (2003), and, specifically associated with the horticultural industry between 2004 and 2006, by Hayes et al. (2007), reviewed and analyzed by Cowie et al. (2008). Subsequent surveys, covering 196 sites across the six largest main Hawaiian islands during 2006–2010, have resulted in the additional new records reported here. We surveyed 29 locations on Kaua\u27i, 48 on O\u27ahu, 13 on Moloka\u27i, 50 on Maui, 4 on Lāna\u27i, and 52 on Hawai\u27i. Sites ranged from highly disturbed lowland habitats dom-inated by nonnative vegetation to high elevation habitats at which most of the vegetation was native. Also included were a number of horticultural nurseries and agricultural re -search stations. A small number of additional records based on collections by collaborators (1996–2007) are also included, as well as 2004–2005 records of Allopeas clavulinum that were inadver-tently omitted by Hayes et al. (2007). We document here the new state and island records. A more comprehensive analysis and discussion of all records will be published elsewhere. Collections were made by Kenneth A. Hayes (KAH), Norine W. Yeung (NWY), Jay nee R. Kim (JRK), Robert H. Cowie (RHC), and others as indicated. All collected material, not only that reported here, is deposited in the Bishop Museum (BPBM) Malacology Collection. Catalog numbers are BPBM Malacology Collection numbers. Assignments to families fol-low Robinson (1999), with the exception of Bulimulus guadalupensis, which is assigned to the Orthalicidae following Bouchet & Rocroi (2005) rather than Buli mul idae, which these authors placed as a subfamily of Orthalicidae. Families are treated alphabetically. Latitude and longitude coordinates were recorded by GPS

Diverse Gastropod Hosts of Angiostrongylus cantonensis, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands

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\u27s 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

Overlooked but not forgotten: the first new extant species of Hawaiian land snail described in 60 years, Auriculella gagneorum sp. nov. (Achatinellidae, Auriculellinae)

Recent surveys of Oahu’s Waianae Mountains uncovered a small, previously undescribed species of Auriculella that is conchologically similar to the three members of the A. perpusilla group all of which are endemic to the Koolau Mountain Range. However, sequence data demonstrate that the perpusilla group is not monophyletic. Moreover, the new species is not closely related to A. perpusilla or A. perversa, the only extant members of the group, but instead is sister to A. tenella, a species from the high spired A. castanea group. A neotype is designated for A. auricula, the type species of Auriculella; all members of the conchologically similar perpusilla group are anatomically redescribed; and lectotypes designated for A. minuta, A. perversa, and A. tenella. The new species is described and compared to the type of the genus, members of the perpusilla group, and the genetically similar species A. tenella

Overlooked but not forgotten: the first new extant species of Hawaiian land snail described in 60 years, Auriculella gagneorum sp. nov. (Achatinellidae, Auriculellinae)

Recent surveys of Oahu’s Waianae Mountains uncovered a small, previously undescribed species of Auriculella that is conchologically similar to the three members of the A. perpusilla group all of which are endemic to the Koolau Mountain Range. However, sequence data demonstrate that the perpusilla group is not monophyletic. Moreover, the new species is not closely related to A. perpusilla or A. perversa, the only extant members of the group, but instead is sister to A. tenella, a species from the high spired A. castanea group. A neotype is designated for A. auricula, the type species of Auriculella; all members of the conchologically similar perpusilla group are anatomically redescribed; and lectotypes designated for A. minuta, A. perversa, and A. tenella. The new species is described and compared to the type of the genus, members of the perpusilla group, and the genetically similar species A. tenella

Correction: Diverse Gastropod Hosts of Angiostrongylus cantonensis, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands.

[This corrects the article DOI: 10.1371/journal.pone.0094969.]

Diverse Gastropod Hosts of <i>Angiostrongylus cantonensis</i>, the Rat Lungworm, Globally and with a Focus on the Hawaiian Islands

<div><p>Eosinophilic meningitis caused by the parasitic nematode <i>Angiostrongylus cantonensis</i> 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 <i>Angiostrongylus cantonensis</i>. 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 <i>Angiostrongylus cantonensis</i> 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 (<i>Oxychilus alliarius</i>, <i>Cyclotropis</i> sp.) and two native species (<i>Philonesia</i> sp., <i>Tornatellides</i> 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 <i>Laevicaulis alte</i>. This knowledge of the intermediate host range of <i>Angiostrongylus cantonensis</i> 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.</p></div

The extent of gastropod sampling throughout the main Hawaiian Islands.

<p>To show the broad geographic coverage, the map includes only sites 10 km or more away from each other.</p