The next species of snail host extraordinaire first came to my attention as the first intermediate host of the feline trematode Platynosomum fastosum. It is known as the miniature awl snail or by its binomial name Subulina octona.
Subulina octona was originally native to the tropical parts of the Americas and the Caribbean. However, the current distribution is extensive due to introductions into other parts of the world. The snail has been reported in Europe (Denmark, Germany, Czech Republic), Sri Lanka and several island nations of Oceania such as Fiji, Samoa, Vanuatu etc. Whether the introductions were accidental or deliberate is currently unknown.
If you were to come across this terrestrial, air breathing snail you would observe the following. Subulina octona is an elegant, small snail measuring only 1.4 - 1.7 cms. The thin, glossy, pale yellow to brown shell is narrow, tapering and long with 8 - 11 whorls ending in an ovate aperture.
S. octona live in moist ground litter in forests but are also capable of thriving in greenhouses and hothouses. A distinctive feature of the life history that D'avila et al. record in their 2018 article involves "egg-retaining", which refers to a reproductive phenomenon in which a major part of the embryonic development occurs inside the body of the parent snail, and the egg when laid has a well-developed embryo. This strategy along with a long life span, several reproductive events per year and high survival of juveniles all result in S. octona being a successful invader.
This snail has an impressive ability to host parasites whose identities span both helminth phyla. It plays the role of intermediate host to trematodes, nematodes and cestodes including:
(1) Postharmostomum gallinarum, the cecal fluke of chickens, the life cycle of which involves S. octona and was worked out in Hawaii as early as 1940 by Dr. Joseph Alicata.
(2) Tamerlania bragai, the kidney fluke of domestic pigeons, the life cycle of which involves S. octona andwas worked out in Puerto Rico in 1945 by Dr. Jose Maldonado.
(3) Angiostrongylus cantonensis, the rat lungworm, which typically uses slugs and snails of other genera. A very interesting paper from Brazil by Caldeira et al. records S. octona as a naturally infected intermediate host of the A. cantonensis, harboring on average 20 L2/L3 larvae per snail.
(4) Angiostrongylus vasorum, the french heartworm: A paper published by Bessa et al. shows that S. octona infected with A. vasorum were capable of infecting a dog in an experimental setting, resulting in a patent infection in 49 days.
(5) Davainea proglottina: Cysticeroids of the poultry cestode Davainea were found in S. octona in Cuba. There was also a unique seasonal variation recorded by Perez et al, who observed cysticercoids only in February, May and August.
The wackiest thing about this snail is that there are sources (listed on the first page of a Google search) which sell awl snail adults for 2 Euros each (as of March 28, 2020). Buying and shipping this snail to your location is a terrible idea because it is a highly invasive species and considered an agricultural pest. There is certainly much ink spilled on the terrifying effects of introducing invasive species to novel non-native habitats, and the practice is not commendable.
References:
Title reference: The title of this post is a play on the common name of the snail (Miniature awl snail) and the small pointed tool used for piercing holes called the awl.
Juřičková, L. U. C. I. E. "Subulina octona (Bruguière, 1798)–a new greenhouse species for the Czech Republic (Mollusca: Gastropoda: Subulinidae)." Malacologica Bohemoslovaca 5 (2006): 1-2.
Alicata, Joseph E. "The life cycle of Postharmostomum gallinum, the cecal fluke of poultry." The Journal of Parasitology 26.2 (1940): 135-143.
Maldonado, José F. "The life cycle of Tamerlania bragai, Santos 1934,(Eucotylidae), a kidney fluke of domestic pigeons." The Journal of Parasitology 31.5 (1945): 306-314.
Caldeira, Roberta Lima, et al. "First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935)(Nematoda: Metastrongylidae) in Brazil." Memórias do Instituto Oswaldo Cruz 102.7 (2007): 887-889.
Bessa, EC de A., et al. "Biological development of Angiostrongylus vasorum (Baillet) Kamensky (Nematoda, Metastrongylidae) in Subulina octona Bruguière (Mollusca, Subulinidae) in laboratory conditions." Revista Brasileira de Zoologia 17.1 (2000): 29-41.
Perez, A., et al. "Seasonal dynamics of the cysticercoids of Davainea proglottina in the intermediate host Subulina octona." Revista Avicultura, Cuba 24.3/4 (1980): 223-225.
Subulina octona was originally native to the tropical parts of the Americas and the Caribbean. However, the current distribution is extensive due to introductions into other parts of the world. The snail has been reported in Europe (Denmark, Germany, Czech Republic), Sri Lanka and several island nations of Oceania such as Fiji, Samoa, Vanuatu etc. Whether the introductions were accidental or deliberate is currently unknown.
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| Subulina octona By Luis Ruiz Berti, Creative Commons CC BY-SA via Wikimedia |
If you were to come across this terrestrial, air breathing snail you would observe the following. Subulina octona is an elegant, small snail measuring only 1.4 - 1.7 cms. The thin, glossy, pale yellow to brown shell is narrow, tapering and long with 8 - 11 whorls ending in an ovate aperture.
S. octona live in moist ground litter in forests but are also capable of thriving in greenhouses and hothouses. A distinctive feature of the life history that D'avila et al. record in their 2018 article involves "egg-retaining", which refers to a reproductive phenomenon in which a major part of the embryonic development occurs inside the body of the parent snail, and the egg when laid has a well-developed embryo. This strategy along with a long life span, several reproductive events per year and high survival of juveniles all result in S. octona being a successful invader.
This snail has an impressive ability to host parasites whose identities span both helminth phyla. It plays the role of intermediate host to trematodes, nematodes and cestodes including:
(1) Postharmostomum gallinarum, the cecal fluke of chickens, the life cycle of which involves S. octona and was worked out in Hawaii as early as 1940 by Dr. Joseph Alicata.
 |
| Subulina octona By Bruguière, 1789 - Naturalis Biodiversity Center, Creative Commons CC0 via wikimedia |
(3) Angiostrongylus cantonensis, the rat lungworm, which typically uses slugs and snails of other genera. A very interesting paper from Brazil by Caldeira et al. records S. octona as a naturally infected intermediate host of the A. cantonensis, harboring on average 20 L2/L3 larvae per snail.
(4) Angiostrongylus vasorum, the french heartworm: A paper published by Bessa et al. shows that S. octona infected with A. vasorum were capable of infecting a dog in an experimental setting, resulting in a patent infection in 49 days.
(5) Davainea proglottina: Cysticeroids of the poultry cestode Davainea were found in S. octona in Cuba. There was also a unique seasonal variation recorded by Perez et al, who observed cysticercoids only in February, May and August.
The wackiest thing about this snail is that there are sources (listed on the first page of a Google search) which sell awl snail adults for 2 Euros each (as of March 28, 2020). Buying and shipping this snail to your location is a terrible idea because it is a highly invasive species and considered an agricultural pest. There is certainly much ink spilled on the terrifying effects of introducing invasive species to novel non-native habitats, and the practice is not commendable.
References:
Title reference: The title of this post is a play on the common name of the snail (Miniature awl snail) and the small pointed tool used for piercing holes called the awl.
Juřičková, L. U. C. I. E. "Subulina octona (Bruguière, 1798)–a new greenhouse species for the Czech Republic (Mollusca: Gastropoda: Subulinidae)." Malacologica Bohemoslovaca 5 (2006): 1-2.
D’ávila, Sthefane, et al. "Life history of Subulina octona (Brugüière)(Gastropoda: Pulmonata: Subulinidae) based on four-year laboratory observations and a comparative histological analysis of egg-retaining and ovoviviparous subulinids." Journal of Natural History 52.23-24 (2018): 1551-1569.
Maldonado, José F. "The life cycle of Tamerlania bragai, Santos 1934,(Eucotylidae), a kidney fluke of domestic pigeons." The Journal of Parasitology 31.5 (1945): 306-314.
Caldeira, Roberta Lima, et al. "First record of molluscs naturally infected with Angiostrongylus cantonensis (Chen, 1935)(Nematoda: Metastrongylidae) in Brazil." Memórias do Instituto Oswaldo Cruz 102.7 (2007): 887-889.
Bessa, EC de A., et al. "Biological development of Angiostrongylus vasorum (Baillet) Kamensky (Nematoda, Metastrongylidae) in Subulina octona Bruguière (Mollusca, Subulinidae) in laboratory conditions." Revista Brasileira de Zoologia 17.1 (2000): 29-41.
Perez, A., et al. "Seasonal dynamics of the cysticercoids of Davainea proglottina in the intermediate host Subulina octona." Revista Avicultura, Cuba 24.3/4 (1980): 223-225.
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