Tag Archives: invasive species

Naesiotus in Spain

The globalisation of snails has taken a next step: Ramos Sánchez et al. just published a first record of a Bulimulidae species in Europe.

schermafbeelding 2019-01-04 om 06.14.24

Their abstract reads: “In the this article, the presence of a Bulimulidae species, classified as Naesiotus quitensis (Pfeiffer, 1848), is reported from an urban park in Madrid (Spain). This is the first citation of a species of this highly diversified Neotropical gastropod family in Europe. The species seems established in the park, but the ways of its introduction are unknown”.

Although it is a very slow process, the introduction of alien species in other ecological realms is clearly the consequence of human interventions, one way or the other. Hence there is little doubt that this introduction was a human act. We can only hope that the Spanish authorities will at least take monitoring actions.

Ramos Sánchez, J.M. et al., 2018. First citation for an exotic Bulimulidae species in Europe. Folia conchyliologica, 47: 11-14.


Ruminia decollata in Cordoba

Reyna & Gordillo just published a brief research note in which they report the finding of specimens of Ruminia decollata (Linnaeus, 1758) in Córdoba Province, Argentina.

According to these authors this snail is a potential host of roundworms that are common in dogs and cats, and thus may also affect susceptible humans. Moreover, this alien species may affect crops and horticultural products.

Reyna, P. & Gordillo, S., 2018. First report of the non-native snail Rumina decollata (Linnaeus, 1758) (Subulinidae: Gastropoda) in Córdoba (Argentina): implications for biodiversity and human health. – American Malacological Bulletin, 36 (1): 150-152.

Newly introduced snail

Agudo-Padrón is a frequent author of news about the southern Brazilian malacofauna. This time he published about a new introduction of a species from Asia, which he identified as Macrochlamys cf. indica (Benson, 1832).

This record was published in a new online journal from the University of El Salvador, named ‘Minerva’; a name which is already applied by at least 2 other journals and thus may be considered as a junior homonym 🙂

Agudo-Padrón, I & Souza da Luz, J., 2018 (‘2017’). Primer record confirmado de ocurrencia de un Caracol terrestre indo-asiático en Brasil y las Américas. – Revista Minerva, El Salvador, 1: 19-27.

A ritual link to snail invaders

Vazquez et al. (2017) recently published interesting research related to invasions. Their abstract reads as follows “The giant African snail, Lissachatina fulica, is considered one of the most invasive species worldwide, acting as a crop pest and diseases vector. It was first detected in Cuba in 2014 and is dispersing throughout Havana. We mapped 34 sites in the vicinity of Havana to assess its spread and analysed ecological (forestation and humidity) and anthropogenic (pollution and religious sites) factors in relation to the presence/absence of the snails using multivariate correspondence analysis. There were 14 sites at which the snail was present and where religious rituals of the Yoruba creed, an African rooted religion, were observed. No other variables showed significant relationships. This indicates that the rituals may be a major factor in the dispersal of the snail in Havana and more widely in Cuba. In light of this an outreach program with key Yoruba leaders may help in slowing the dispersal of the snail within Cuba, once the threats posed by this species are known”.

Reading through their paper I noticed that there may be also a ritual origin of the introduction of this snail in Florida, while there are indications that something similar maybe at stake in Brazil. Perhaps time for an ethnobiological approach complementary to the usual eradication schemes? Eradication without taking the driving force away behind the spread of this snail may simply not be sufficient.

Vazquez, A.,  Sanchez, J., Martinez, E. & Alba, A., 2017. Facilitated invasion of an overseas invader: human mediated settlement and expansion of the giant African snail, Lissachatina fulica, in Cuba. – Biological Invasions, 19 (1):1-4.

Achatina fulica east of Andes in Ecuador

Goldyn et al. have just published a paper of which the abstract reads “[w]e are reporting the first locality of invasive giant African snail, Achatina (Lissachatina) fulica (Férussac, 1821) in the Ecuadorian Amazon. It was found present in 32 out of 50 urban sites studied. The abundance where present was relatively high when compared to literature from other parts of the world. The snails were found in aggregations, usually foraging — most often on dogs’ feces. Statistical analysis suggests a preference toward this source of alimentation. This is the first report of such preference in this species, which is highly significant considering the possible implications. Besides the threat posed by an invasive species to the invaluable ecosystems of the Amazon, the pathogens transferred by A. fulica combined with a high abundance of the species in an urban environment and its food preferences may constitute an important health hazard for local human populations”.

This is, however, not the first published occurrence east of the Andes in Ecuador. The same authors have published this, and additional data, before in Folia Malacologica last year. If not an oversight by the reviewers and editor, this so-called “first locality” has to be blamed to the authors.

But the fact as such (if we exclude the many Brazilian occurrences), unfortunately, was waiting just to happen. Hopefully the Ecuadorian authorities nowadays know how they should eradicate this pest before it becomes wide-spread in this area which contain many endemic species.

Goldyn, B., et al., 2017. Urban ecology of invasive giant African snail Achatina fulica (Férussac) (Gastropoda: Achatinidae) on its first recorded sites in the Ecuadorian Amazon. – American Malacological Bulletin, 35: 59-64.

Genetics of invasive Cornu

Another paper on invasive species, i.e. Cornu aspersum in Chile, is entirely devoted to genetics. It was recently published by Nespolo et al. (2014).


The summary of this paper comprises seven items:
1. The distribution of additive vs. non-additive genetic variation in natural populations represents a central topic of research in evolutionary/organismal biology. For evolutionary physiologists, functional or whole-animal performance traits (‘physiological traits’) are frequently studied assuming they are heritable and variable in populations.
2. Physiological traits of evolutionary relevance are those functional capacities measured at the whole-organism level, with a potential impact on fitness. They can be classified as capacities (or performances) or costs, the former being directly correlated with fitness and the latter being inversely correlated with fitness (usually assumed as constraints).
3. In spite of their obvious adaptive significance, the additive genetic variation in physiological traits, and its relative contribution to phenotypic variance (or narrow-sense heritability) in comparison with maternal, dominance or epistatic variance, is known only for a few groups such as insects and mammals.
4. In this study, we assessed the additive and maternal/non-additive genetic variation in a suite of physiological and morphological traits in populations of the land snail Cornu aspersum.
5. Except for dehydration rate (h2 = 0.32 +/- 0.15), egg mass (h2 = 0.82 +/- 0.30) and hatchling mass (h2 = 1.01 +/- 0.31; population = fixed effect), we found very low additive genetic variation. Large non-additive/maternal effects were found in all traits. Cage effects did not change the results, indicating low contribution of common environmental variance to our results. No differences were found between the phenotypic and non-additive genetic variance/covariance matrices.
6. Even though we compared populations across 1300 km in a common garden set-up, our results suggest an absence of physiological as well as morphological differentiation in these populations.
7. These results contrast with previous analyses in the original distributional range of this species, which found high additive genetic variation in morphological traits. These are intriguing results demanding further quantitative genetic studies in the original distributional range of this species as well as the history of colonization of this invasive species.

Especially items 6 and 7 are interesting. Suppose we may see some time a follow-up by these authors.


Nespolo, R.F., Bartheld, J.F., González, A., Bruning, A., Roff, D.A., Bacigalupe, L.D. & Gaitan-Espitia, J.D., 2014. The quantitative genetics of physiological and morphological traits in an invasive terrestrial snail: additive vs. non-additive genetic variation. – Functional Ecology 28 (3): 682-692.

Invasive Deroceras slugs

Just published: a paper by Hutchinson et al. (2014) on invasive Deroceras slugs. The abstract reads:

The article reviews distribution records of Deroceras invadens (previously called D. panormitanum and D. caruanae), adding significant unpublished records from the authors’ own collecting, museum samples, and interceptions on goods arriving in the U.S.A. By 1940 D. invadens had already arrived in Britain, Denmark, California, Australia and probably New Zealand; it has turned up in many further places since, including remote oceanic islands, but scarcely around the eastern Mediterranean (Egypt and Crete are the exceptions), nor in Asia. Throughout much of the Americas its presence seems to have been previously overlooked, probably often being mistaken for D. laeve. New national records include Mexico, Costa Rica, and Ecuador, with evidence from interceptions of its presence in Panama, Peru, and Kenya. The range appears limited by cold winters and dry summers; this would explain why its intrusion into eastern Europe and southern Spain has been rather slow and incomplete. At a finer geographic scale, the occurrence of the congener D. reticulatum provides a convenient comparison to control for sampling effort; D. invadens is often about half as frequently encountered and sometimes predominates. Deroceras invadens is most commonly found in synanthropic habitats, particularly gardens and under rubbish, but also in greenhouses, and sometimes arable land and pasture. It may spread into natural habitats, as in Britain, South Africa, Australia and Tenerife. Many identifications have been checked in the light of recent taxonomic revision, revealing that the sibling species D. panormitanum s.s. has spread much less extensively. A number of published or online records, especially in Australia, have turned out to be misidentifications of D. laeve.



Hutchinson, J., Reise, H. & Robinson, D., 2014. A biography of an invasive terrestrial slug: the spread, distribution and habitat of Deroceras invadens. NeoBiota 23: 17–64. Available at http://neobiota.pensoft.net/articles.php?id=4006.