Predation by invasive Platydemus manokwari flatworms: a laboratory study
PDF

Keywords

Platydemus manokwari
ecology
invasion biology
snails
diet
invasive species

How to Cite

Gerlach, J. (2019). Predation by invasive Platydemus manokwari flatworms: a laboratory study. Biological Letters, 54(1), 47–60. https://doi.org/10.2478/biolet-2019-0005

Number of views: 307


Number of downloads: 103

Abstract

Platydemus manokwari de Beauchamp, 1963 is an invasive flatworm found on islands in the tropics, especially in the Pacific Ocean. It has been implicated in the decline of several snail populations, including the extinction of some Partula species. Its predatory behaviour was investigated to quantify predation rates and elucidate climatic influences. This laboratory study of the invasive flatworm confirms earlier reports that P. manokwari is a generalist predator of snails. It prefers small prey and avoids species defended by copious mucus, chemical defences or a tough integument. Prey are found by following damp mucus trails up to 15 h old. Flatworm activity is limited by temperature and humidity, with peak feeding at 24–30°C and 85–95% humidity. This determines the geographical spread of the species and probably also the effectiveness of arboreal predation. Aboveground air circulation leads to drying, reducing the ability of the flatworms to locate trails and remain active high off the ground. Local climatic factors may dictate how significantly P. manokwari affects snail populations.

https://doi.org/10.2478/biolet-2019-0005
PDF

References

Chiba S. 2003. Species diversity and conservation of Mandarina, an endemic land snail of the Ogasawara Islands. Global Environ. Res. 7: 29–37.

De Beauchamp P. 1962. Platydemus manokwari n. sp., planaire terrestre de la Nouvelle-Guinee´ Hollandaise. Bull. Soc. Zool. France 87: 609–615.

Gerlach J. 2016. Icons of Evolution: Pacific island tree snails of the family Partulidae. Phelsuma Press, Cambridge.

Iwai N., Sugiura S., Chiba S. 2010. Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida). Naturwissenschaften 97: 997–1002.

Justine J., Winsor L., Gey D., Gros P., Thévenot J. 2014. The invasive New Guinea flatworm Platydemus manokwari in France, the first record for Europe: time for action is now. PeerJ2: e297.

Justine J, Winsor L., Barrière P., Fanai C., Gey D., Han A. W. K., La Quay-Velázquez G., Lee B. P. Y., Lefevre J., Meyer J., Philippart D., Robinson D. G., Thévenot J., Tsatsia F. 2015. The invasive land planarian Platydemus manokwari (Platyhelminthes, Geoplanidae): records from six new localities, including the first in the USA. PeerJ 3: e1037.

Kaneda M., Kitagawa K., Ichinohe F. 1990. Laboratory rearing method and biology of Platydemus manokwari De Beauchamp (Tricladida: Terricola: Rhynchodemidae). App. Entomol. Zool. 25: 524–528.

Kaneda M., Kitagawa K., Nagai H., Ichinohe F. 1992. The effects of temperature and prey species on the development and fecundity of Platydemus manokwari De Beauchamp (Tricladida: Terricola: Rhynchodemidae). Research Bull. Plant Prot. Serv. Japan 28: 7–11.

Kawakatsu M., Ogren R. E., Muniappan R. 1992. Resdescription of Platydemus manokwari de Beauchamp, 1962 Turbellaria: Tricladida: Terricola) from Guam and the Philippines. Proc. Jap. Soc. Syst. Zool. 47: 11–25.

Keppel G., Morrison C, Meyer J.-Y., Boehmer H. J. 2014. Isolated and vulnerable: the history and future of Pacific island terrestrial biodiversity. Pacific Conserv. Biol. 20: 136–145.

Kerr A. M. 2013. The partulid tree snails (Partulidae: Stylommatophora) of the Mariana Islands, Micronesia. Univ. Guam Marine Lab. Tech. Rep. 152.

Mead A. R. 1963. A flatworm predator of the giant African snail Achatina fulica in Hawaii. Malacologia 1: 305–311.

Ohbayashi T., Okochi I., Sato H., Ono T. 2005. Food habit of Platydemus manokwari De Beauchamp, 1962 (Tricladida: Terricola: Rhynchodemidae), known as a predatory flatworm of land snails in the Ogasawara (Bonin) Islands, Japan. App. Entomol. Zool. 40: 609–614.

Régnier C., FontAine B., Bouchet P. 2009. Not knowing, not recording, not listing: numerous unnoticed mollusc extinctions. Conserv. Biol. 23: 1214–1221.

Sugiura S. 2009. Seasonal fluctuation of invasive flatworm predation pressure on land snails: implications for the range expansion and impacts of invasive species. Biol Conserv 142: 3013–3019.

Sugiura S. 2010. Prey preference and gregarious attacks by the invasive flatworm Platydemus manokwari. Biol. Invasions 12: 1499–1507.

Sugiura S., Okochi I, Tamada H. 2006. High predation pressure by an introduced flatworm on land snails on the oceanic Ogasawara islands. Biotropica 38: 700–703.

Sugiura S., Yamaura Y. 2009. Potential impacts of the invasive flatworm Platydemus manokwari on arboreal snails. Biological Invasions 11: 737–742.

Tan H. H. 2017. New Guinea flatworm hunting a land slug. Singapore Biodiversity Records (2017): 128–129.

Wood J.R., Alcover J. A., Blackburn T. N., Bover P., Duncan R. P., Hume J. P., Louys J., Meijer H. J. M., Rando J. C., Wilmshurst J. M. 2017. Island extinctions: processes, patterns, and potential for ecosystem restoration. Environ. Conserv. 44: 348–358.