Comparative analysis of wild and long term captive bred Partula snails using morphometrics and population data

Trickett, E

Abstract

Partula snails are one genus of the Partulidae family of air breathing, land snails that are endemic to the Pacific Islands. Over 100 partulid species are recognised with over half these species known to have existed and endemic to the Society Islands (within the Pacific islands). It is thought that 56 of these endemic Partula species are now extinct on the Society Islands with the remaining species critically endangered. This devastating extinction is mainly the result of the introduced carnivorous rosy wolf snail, Euglandina rosea in 1974. The most imposing threat today is the introduced New Guinea flatworm, Platydemus manokwari. To save the remaining Partula species from extinction, specimens have been collected since 1962 to start a captive breeding programme coordinated by the Zoological Society of London (ZSL). Over 15 species are kept in captivity currently. Several reintroductions have taken place with over 10,000 snails being reintroduced to the islands with varying levels of success. Partula have been in captivity now for over 60 years, with many of the species founded with small numbers. There is concern about how this species may be adapting morphologically to their captive environment as they are known to be sensitive to environmental changes. This study focused on ten species of Partula with multiple generations in captivity, which made it possible to compare the morphology of wild to captive-bred specimens. The study found that seven of the ten species displayed no significant morphological changes during long-term captivity (P. clara, P. garrettii, P. hebe bella, P. otaheitana, P. rosea, P. suturalis strigosa and P. varia). Three species did show significant morphological changes at various stages throughout captivity. The morphological changes that P. faba displayed were likely adaptations to its captive environment. Partula faba did not survive in captivity as a result of the low genetic diversity within the captive population due to the depleted wild population. Partula affinis appears to have gradually changed morphologically to presumably adapt to the captive environment. Partula tohievana displayed morphological changes between two generations only, suggesting a local mutation event caused by low genetic diversity. This species should be monitored in captivity as it may suffer a similar fate to P. faba and face extinction in captivity. Overall, long-term captivity does not appear to have negatively affected the morphology of Partula and therefore suggests positive outcomes for future reintroductions.

Citation

Trickett, E. Comparative analysis of wild and long term captive bred Partula snails using morphometrics and population data. (Dissertation). University of Salford

• Thesis Type: Dissertation
• Deposit Date: Oct 21, 2021
• Publicly Available Date: Oct 21, 2021
• Award Date: Oct 12, 2021