dec 2008
Season's Greetings
22-12-2008 22:48
Dear readers,
Although most of you are unknown to me, I wish you all a good Christmas time and a healthy and prosperous New Year.
Please, do return in 2009, when this blog will be continued...
Although most of you are unknown to me, I wish you all a good Christmas time and a healthy and prosperous New Year.
Please, do return in 2009, when this blog will be continued...
Darwin's year
21-12-2008 21:24
To commemorate Darwin’s Year (200th birthday on
12.2.2009), some organisations start early. Today was
the Darwin Christmas Lecture 2008.
According to Goldschmidt, the publication of “On the origin of species” (1859), which he calls “the most important publication in biology” is even a better milestone for 2009.
The focus of his lecture was on invasive species. Human beings may also be seen as invasive species, since they originated in Africa. However, what worries Goldschmidt is the rapid spread of all kind of plants and animals in human’s trail that often compete with the original flora and fauna.
While at least philosophically speaking, many species could be called ‘invasive species’. Just think of the ancient stock of e.g. land snails colonizing a virgin island (e.g. Galápagos). Let’s call these ‘pioneers’.
Something different is the species that - intentionally or accidentally - is introduced in an other ecosystem, generally by a vector (e.g. a human, ship, airplane). Let’s call these ‘intruders’.
From an evolutionary point of view, pioneers may be far more interesting than intruders. They may radiate into different species, but the outcome is only observable in hindsight after a long lapse of time. However, the effect of intruders is often visible after (mostly) a few decades. Although there are many ‘positive’ intruders - e.g. species used for food or decoration - the ones that are called ‘alien species’ are either economically damaging or provide a health risk. In snails it are the well-known examples of Euglandina or Lissachatina.
Goldsmidth concluded with a short video of the eradication of goats on the Galápagos. You may find it on the Open University at iTunes. But I rather prefer here to show you the place on Santiago Island (James in Darwin’s time) where he landed. More on that in 2009, Darwin’s year...
According to Goldschmidt, the publication of “On the origin of species” (1859), which he calls “the most important publication in biology” is even a better milestone for 2009.
The focus of his lecture was on invasive species. Human beings may also be seen as invasive species, since they originated in Africa. However, what worries Goldschmidt is the rapid spread of all kind of plants and animals in human’s trail that often compete with the original flora and fauna.
While at least philosophically speaking, many species could be called ‘invasive species’. Just think of the ancient stock of e.g. land snails colonizing a virgin island (e.g. Galápagos). Let’s call these ‘pioneers’.
Something different is the species that - intentionally or accidentally - is introduced in an other ecosystem, generally by a vector (e.g. a human, ship, airplane). Let’s call these ‘intruders’.
From an evolutionary point of view, pioneers may be far more interesting than intruders. They may radiate into different species, but the outcome is only observable in hindsight after a long lapse of time. However, the effect of intruders is often visible after (mostly) a few decades. Although there are many ‘positive’ intruders - e.g. species used for food or decoration - the ones that are called ‘alien species’ are either economically damaging or provide a health risk. In snails it are the well-known examples of Euglandina or Lissachatina.
Goldsmidth concluded with a short video of the eradication of goats on the Galápagos. You may find it on the Open University at iTunes. But I rather prefer here to show you the place on Santiago Island (James in Darwin’s time) where he landed. More on that in 2009, Darwin’s year...
Photo of the day (29): Corona
20-12-2008 16:20
Another picture of Corona, this time C. perversa
(Swainson, 1822). This specimen was observed
hibernating in a tree near Puerto Nariño, Amazonas,
Colombia.
Thanks Frank, for the picture.
Thanks Frank, for the picture.
Tepuy
19-12-2008 13:05
Horizontal quartzite caves can’t exist according to
geological knowledge. Yet such caves have been found
in Venezuelan Guayana. Slovakian cavers have explored
the region and found several caves in Roraima and
Chimantá massifs. Of the latter expedition a
documentary has been made, called Tepuy, which
is
available
on DVD.
For all who would like to see this fascinating part of the world and to have an impression of the habitat of several interesting snail species, I recommend this film. Personally I give a five-star WOW!-factor.
For all who would like to see this fascinating part of the world and to have an impression of the habitat of several interesting snail species, I recommend this film. Personally I give a five-star WOW!-factor.
Chirality
18-12-2008 09:19
Chirality is the phenomenon that an assymetric
structure can come in two, non-identical,
mirror-image forms. This phenomenon can be found in
many groups of animals and plants. Land snails are
just one example, leading to sinistral specimens
besides the normal dextral ones in a population
(intra-specific chirality) or sinistral species among
other, dextral species in a group (inter-specific
chirality).
In the Neotropics there are also a few examples of chirality. In Orthalicidae there are three genera: Drymaeus, Liguus and Corona. In the Subulinidae there is an example in Rhodea. And I have seen a report on a sinistral Megalobulimus, but that may be just an aberration, just like the specimens of Rabdotus, Thaumastus and Euglandina that can be found here.
Let’s explore a bit more of it. The first example is Rhodea wallisiana Dohrn, 1875 from Colombia. This is a rare species of which only a few specimens are known, which are all sinistral.
Drymaeus provides another example of a sinistral species, D. tropicalis (Morelet, 1849) from Mexico. Also Corona perversa (Swainson, 1820) - occurring in northern Brazil and the Guianas - and C. regalis (Hupé, 1857) - the latter also westward into lowland Peru and Ecuador - are normally sinistral. There is one taxon, described as Corona incisa forma machadoensis Strebel, 1909 from “Rio Machado” [in Brazil, it might be either Edo. Rodônia, Río Ji-Paraná or Río Machado in Edo. Tocantins, Minas Gerais or Matto Grosso], which is sinistral too.
Finally there are several examples of Liguus species, normally dextral, that show chirality. The excellent website of Emilio Power [unfortunately not longer updated] provides photos of sinistral Liguus vittatus (Swainson, 1822) and L. virgineus (L., 1758).
The phenomenon of chirality presents some interesting biological questions, e.g.:
- what is the genetic basis for each of the two chiral morphs?
- what maintains the chiral dimorphism in some species (intra-specific chirality)?
- what is the role of chirality in speciation?
References:
Grego, J., Steffek, J. & Infante, A.P., 2007. Review of the genus Rhodea (Gastropoda, Pulmonata, Subulinidae), with description of two new species from Colombia. - Basteria 71: 13-28.
In the Neotropics there are also a few examples of chirality. In Orthalicidae there are three genera: Drymaeus, Liguus and Corona. In the Subulinidae there is an example in Rhodea. And I have seen a report on a sinistral Megalobulimus, but that may be just an aberration, just like the specimens of Rabdotus, Thaumastus and Euglandina that can be found here.
Let’s explore a bit more of it. The first example is Rhodea wallisiana Dohrn, 1875 from Colombia. This is a rare species of which only a few specimens are known, which are all sinistral.
Drymaeus provides another example of a sinistral species, D. tropicalis (Morelet, 1849) from Mexico. Also Corona perversa (Swainson, 1820) - occurring in northern Brazil and the Guianas - and C. regalis (Hupé, 1857) - the latter also westward into lowland Peru and Ecuador - are normally sinistral. There is one taxon, described as Corona incisa forma machadoensis Strebel, 1909 from “Rio Machado” [in Brazil, it might be either Edo. Rodônia, Río Ji-Paraná or Río Machado in Edo. Tocantins, Minas Gerais or Matto Grosso], which is sinistral too.
Finally there are several examples of Liguus species, normally dextral, that show chirality. The excellent website of Emilio Power [unfortunately not longer updated] provides photos of sinistral Liguus vittatus (Swainson, 1822) and L. virgineus (L., 1758).
The phenomenon of chirality presents some interesting biological questions, e.g.:
- what is the genetic basis for each of the two chiral morphs?
- what maintains the chiral dimorphism in some species (intra-specific chirality)?
- what is the role of chirality in speciation?
References:
Grego, J., Steffek, J. & Infante, A.P., 2007. Review of the genus Rhodea (Gastropoda, Pulmonata, Subulinidae), with description of two new species from Colombia. - Basteria 71: 13-28.
Decline of molluscs
17-12-2008 22:24
Decline of malacological populations is not limited
to the Neotropics. It is part of a global pattern
and, although we may have to accept it, it has not to
go unnoticed.
Christine Parent has written a small paper earlier this year about this topic. She explains in clear writing what role molluscs play in ecosystems and why it is important to stop their decline.
No doubt that many of my readers may be aware of the existence and the urgency of this problem. But it cannot be stressed enough, so I pass on the reference.
Reference
Parent, C.E., 2008. The global decline of mollsuks. ActionBioscience.org
Christine Parent has written a small paper earlier this year about this topic. She explains in clear writing what role molluscs play in ecosystems and why it is important to stop their decline.
No doubt that many of my readers may be aware of the existence and the urgency of this problem. But it cannot be stressed enough, so I pass on the reference.
Reference
Parent, C.E., 2008. The global decline of mollsuks. ActionBioscience.org
More on Neotropical malacology
16-12-2008 19:33
Yesterday arrived the
Unitas Malacologica
newsletter,
with a report of the CLAMA VII congress in Chile.
More than 280 people from 16 countries attended.
In the report the “Latin American Association for
Malacology (ALM)” is mentioned. However, when I
tried to look it up with Google, I didn’t find any
result. It looks like a “phantom organisation”,
one that exists only virtually (?).
Anyway, I stumbled upon the website of the Sociedad Malacológica de Chile. They appear to have an annual newsletter too, Boletín Amici Molluscarum. In their latest issue (2007) I found a list of members: 57 + 5 members from abroad + 2 honory members. That is much more than the 9 listed in my previous post.
Each number of Amici Molluscorum (at least the more recent ones, but also some of the older) contain a few papers, predominantly on marine molluscs. For a country with such a huge shoreline it should not be a surprise.
In the announcements I saw a paper by one of the members on Pre-Colombian malacology. Also a book on the shell collection of the late Pablo Neruda was mentioned. Probably hard to get outside the country. But I’ll have a look for it, you never know.
Anyway, I stumbled upon the website of the Sociedad Malacológica de Chile. They appear to have an annual newsletter too, Boletín Amici Molluscarum. In their latest issue (2007) I found a list of members: 57 + 5 members from abroad + 2 honory members. That is much more than the 9 listed in my previous post.
Each number of Amici Molluscorum (at least the more recent ones, but also some of the older) contain a few papers, predominantly on marine molluscs. For a country with such a huge shoreline it should not be a surprise.
In the announcements I saw a paper by one of the members on Pre-Colombian malacology. Also a book on the shell collection of the late Pablo Neruda was mentioned. Probably hard to get outside the country. But I’ll have a look for it, you never know.
Photo of the day (28): Drymaeus
15-12-2008 09:01
Alan Pierre Infante kindly sent me some pictures of a
Drymaeus species encountedred by him in Colombia,
Dept. Quindío, Calarcá.
The colour of the tentacles are unlike anything I have seen so far in the Orthalicidae. What would the selective advantage be of bright coloured tentacles?
Although it is difficult to say with certainty from this picture alone, I think this species is probably Drymaeus baranguillanus (Pfeiffer, 1853).
Thanks Alan!
The colour of the tentacles are unlike anything I have seen so far in the Orthalicidae. What would the selective advantage be of bright coloured tentacles?
Although it is difficult to say with certainty from this picture alone, I think this species is probably Drymaeus baranguillanus (Pfeiffer, 1853).
Thanks Alan!
Photo of the day (27): Incidostosma
13-12-2008 14:23
This photo is part of an e-card with Season’s
Greeting that I received from Jozef Grego. It is
always nice to see a live snail instead of only a
shell. It is like seeing a photograph of a person
after you have read several of his/her publications.
You get a face to a name.
Thanks Jozef!
Thanks Jozef!
Meeting colleagues
12-12-2008 14:09
Today I attended a meeting with colleagues
from
Naturalis.
It had something special since it served also to
acquaintance people that will form the new Dept.
of Terrestrial Zoology as of 1 January 2009.
The organisation goes through a lot of changes, the most important is the recently announced transformation into the ‘Nederlands Centrum voor Biodiversiteit’ (NCB; Dutch Center for Biodiversity). It will involve a merger of the Zoological Museum in Amsterdam and the National Herbarium (Leiden, Wageningen). The consequences will be additional facilities and housing in due time.
It was the first time that entomologists, malacologists and herpetologists were presenting their research to each other, together with associate researchers. My presentation was entitled “Neotropical land snails: a continued fascination”.
Here a quick overview of the Orthalicidae is depicted. Note the enormous variation, both in shell shape, size, coloration, etc. Also there are several examples of adaptive radiation (Galápagos) and non-adaptive radiation (Guayana Highlands) represented in this family. They keep me faciated...
The organisation goes through a lot of changes, the most important is the recently announced transformation into the ‘Nederlands Centrum voor Biodiversiteit’ (NCB; Dutch Center for Biodiversity). It will involve a merger of the Zoological Museum in Amsterdam and the National Herbarium (Leiden, Wageningen). The consequences will be additional facilities and housing in due time.
It was the first time that entomologists, malacologists and herpetologists were presenting their research to each other, together with associate researchers. My presentation was entitled “Neotropical land snails: a continued fascination”.
Here a quick overview of the Orthalicidae is depicted. Note the enormous variation, both in shell shape, size, coloration, etc. Also there are several examples of adaptive radiation (Galápagos) and non-adaptive radiation (Guayana Highlands) represented in this family. They keep me faciated...
Photo of the day (26): Corona
11-12-2008 11:39
This is Corona pfeifferi, a species that was
described by Hidalgo in 1869. The type locality is
Canelos, Prov. Pastaza, Ecuador. Corona is a typical
rain forest genus, with some known sinistral forms.
But C. pfeifferi is a normal, dextral
species.
It is a beauty, isn’t it?
Thanks Valentín for the picture!
It is a beauty, isn’t it?
Thanks Valentín for the picture!
Carination revisited
10-12-2008 16:56
While searching some literature on Chile for a
friend, I found an interesting paper on the ecology
of a Bostryx species from the desert in the northern
part of the country. It also sheds some new light on
the phenomenon of carianation (subject of an upcoming
paper) and relates to the specialization / speciation
discussion briefly summarized
here
and
here.
In 1970, the paleontologist Herm described a new species, Bostryx variabilis, from Pleistocene marine sediments near Antofagasta.
Map showing the area just north of Antafagasta (from Herm, 1970)
To explain the occurrence of this terrestrial species amidst marine facies, he postulated a sea level regression-transgression. The species is carinated (keeled) and partially uncoiled.
In 1981, Alan Craig -a geographer- did field work in the same region and made some observations which questioned Herm’s hypothesis. He found many specimens of B. variabilis in nearby localitions, but they were restricted to places where also fossilized lichens occurred. Moreover he found transitions to a Recent species, B. mejillonensis (Pfeiffer, 1857).
Isotopic dating yielded an age of 2180 +/- 50 yr B.P., making the Pleistocene sea level change as postulated by Herm unnecessary for the type locality.
But how to explain the occurrence of B. mejillonensis-variabilis at this place? Eventually it appeared that Bostryx mejillonensis was only found in localities where meteorological circumstances sustained epiphytic colonies of lichens on cacti at the top of a hill nearby the type locality of Herm. At the slopes below the elevation where the seasonal fog banks have influence, the hyperarid desert constitutes a barrier for the dispersal of snails. The hill top thus forms an ecological island. This finally led Craig to hypothesize that B. mejillonensis had been forced outside their habitat into the surrounding desert from where they were unable to escape. Rapid changing environmental conditions would have ‘stress-induced’ a speciation process which led to the aberrant form of B. variabilis. Support for this hypothesis were field observations by Craig of runnels, caused by occasional winter rains, leading to downslope transportation of snails.
Area just north of Antafagasta with the localities mentioned by Herm (1970) and Craig (1985) indicated. The distribution area of lichens indicated by Craig marked on Morro Moreno in white (source: Google Earth).
Given the hypothesis briefly outlined above, my question is: is carination as observed in other places (e.g., here and here) also best explained as a ‘stress-induced speciation process’? If so, are there analogous ecological circumstances that force snails to transform into aberrant, carinated and -sometimes even - uncoiled shells?
References:
Craig, A.K., 1985. Speciation and age revision of the Atacaman snail Bostryx variabilis Herm. - Quarternary Research 23: 382-387.
Herm, D., 1970. Bostryx variabilis n.sp., eine Landschnecke aus dem Altpleistozän von Mejillones, Nordchile. - Mittheilungen Bayerischen Staatssammlung Paläontologie und historische Geologie 10: 189-198.
In 1970, the paleontologist Herm described a new species, Bostryx variabilis, from Pleistocene marine sediments near Antofagasta.
Map showing the area just north of Antafagasta (from Herm, 1970)
To explain the occurrence of this terrestrial species amidst marine facies, he postulated a sea level regression-transgression. The species is carinated (keeled) and partially uncoiled.
In 1981, Alan Craig -a geographer- did field work in the same region and made some observations which questioned Herm’s hypothesis. He found many specimens of B. variabilis in nearby localitions, but they were restricted to places where also fossilized lichens occurred. Moreover he found transitions to a Recent species, B. mejillonensis (Pfeiffer, 1857).
Isotopic dating yielded an age of 2180 +/- 50 yr B.P., making the Pleistocene sea level change as postulated by Herm unnecessary for the type locality.
But how to explain the occurrence of B. mejillonensis-variabilis at this place? Eventually it appeared that Bostryx mejillonensis was only found in localities where meteorological circumstances sustained epiphytic colonies of lichens on cacti at the top of a hill nearby the type locality of Herm. At the slopes below the elevation where the seasonal fog banks have influence, the hyperarid desert constitutes a barrier for the dispersal of snails. The hill top thus forms an ecological island. This finally led Craig to hypothesize that B. mejillonensis had been forced outside their habitat into the surrounding desert from where they were unable to escape. Rapid changing environmental conditions would have ‘stress-induced’ a speciation process which led to the aberrant form of B. variabilis. Support for this hypothesis were field observations by Craig of runnels, caused by occasional winter rains, leading to downslope transportation of snails.
Area just north of Antafagasta with the localities mentioned by Herm (1970) and Craig (1985) indicated. The distribution area of lichens indicated by Craig marked on Morro Moreno in white (source: Google Earth).
Given the hypothesis briefly outlined above, my question is: is carination as observed in other places (e.g., here and here) also best explained as a ‘stress-induced speciation process’? If so, are there analogous ecological circumstances that force snails to transform into aberrant, carinated and -sometimes even - uncoiled shells?
References:
Craig, A.K., 1985. Speciation and age revision of the Atacaman snail Bostryx variabilis Herm. - Quarternary Research 23: 382-387.
Herm, D., 1970. Bostryx variabilis n.sp., eine Landschnecke aus dem Altpleistozän von Mejillones, Nordchile. - Mittheilungen Bayerischen Staatssammlung Paläontologie und historische Geologie 10: 189-198.
A biogeographical enigma
07-12-2008 12:03
This qualification is given to Easter Island, an
island that politically speaking belongs to the
Neotropics (it is part of Chile). Jared Diamond used
Easter Island as one of the cases in his book
Collapse (2004), in which he illustrated how ancient
cultures vanished and how modern cultures are
vulnerable for it. (I propose you look at
this review,
written in 2005, to read some context for the
current situation).
There is a comprehensive review of the terrestrial mollusks by Boyko & Cordeiro (2001), who list six species. Most of them are more or less cosmopolitan species and introduced by human activities. Only Pacificella variabilis Odhner, 1922 is confined to the Pacific.
Now there is a new paper by Kirch et al.* on the malacofauna of this island, for which malacological reports are scarce. The authors not only report three additional introduced species, but also describe a subfossil new endemic one: Hotumatua anakenana gen.nov, spec.nov.
Although Easter Island has now only a very impoverished land snail fauna, Kirch et al. suspect that the island once had a much richer terrestrial fauna. This paper is evidence of that fact.
References:
Boyko, C.B. & Cordeiro, J.R., 2001. The terrestrial Mollusca of Easter Island (Gastropoda, Pulmonata). - Basteria 65: 17-25.
Diamond, J., 2004. Collapse. North Point Press, New York.
Kirch, P.V., Christensen, C.C. & Steadman, D.W., 2009. Subfossil land snails from Easter Island, including Hotumatua anakenana, new genus and species (Pulmonata: Achatinellidae). - Pacific Science 63: 105-122.
There is a comprehensive review of the terrestrial mollusks by Boyko & Cordeiro (2001), who list six species. Most of them are more or less cosmopolitan species and introduced by human activities. Only Pacificella variabilis Odhner, 1922 is confined to the Pacific.
Now there is a new paper by Kirch et al.* on the malacofauna of this island, for which malacological reports are scarce. The authors not only report three additional introduced species, but also describe a subfossil new endemic one: Hotumatua anakenana gen.nov, spec.nov.
Although Easter Island has now only a very impoverished land snail fauna, Kirch et al. suspect that the island once had a much richer terrestrial fauna. This paper is evidence of that fact.
References:
Boyko, C.B. & Cordeiro, J.R., 2001. The terrestrial Mollusca of Easter Island (Gastropoda, Pulmonata). - Basteria 65: 17-25.
Diamond, J., 2004. Collapse. North Point Press, New York.
Kirch, P.V., Christensen, C.C. & Steadman, D.W., 2009. Subfossil land snails from Easter Island, including Hotumatua anakenana, new genus and species (Pulmonata: Achatinellidae). - Pacific Science 63: 105-122.
Update on Dominican Amphibulima
04-12-2008 21:23
After all those ‘varia’ subjects it’s time to pay
attention to Neotropical snails again.
Today I met with Ad Hovestadt, specialist on Antillean snails, to discuss about his recent trip to Dominica. He showed me some Amphibulima shells and suggested that the pictures shown here are actually Amphibulima patula (Bruguière, 1792), a young specimen. The two other species known from the island - A. pardalina Guppy, 1868 and A. browni Pilsbry, 1899 - have also be collected by him and he gave me an alcohol preserved specimen of the former. This specimen was depicted in this post.
We decided to write on joint paper on these and other species which he collected during his trip.
Today I met with Ad Hovestadt, specialist on Antillean snails, to discuss about his recent trip to Dominica. He showed me some Amphibulima shells and suggested that the pictures shown here are actually Amphibulima patula (Bruguière, 1792), a young specimen. The two other species known from the island - A. pardalina Guppy, 1868 and A. browni Pilsbry, 1899 - have also be collected by him and he gave me an alcohol preserved specimen of the former. This specimen was depicted in this post.
We decided to write on joint paper on these and other species which he collected during his trip.
Proficiat Dr Bas Kokshoorn
03-12-2008 21:49
It’s not an everyday occasion to report on, a
malacological thesis. Today Bas Kokshoorn defended
his Ph.D. thesis at the University of Leiden.
The thesis consists of eight chapters of which several will be published later in peer-reviewed journals. I mentioned already the chapter on prime and remnant species. Other chapters deal with an introduction to the family Chondrinidae, the historical biogeography of the genus Chondrina, a phylogenetic analysis of the Abida secale-complex and its ecophenotypic variation and finally a taxonomic revision of the Chondrinidae.
In the discussion I found the part on the altitudinal gradients and shell morphology particularly interesting. To what extent is selection expressed when comparing samples collected on different mountain transects? Also the factors explaining the variation were discussed. The methodology applied may be applicable to some questions I have about some Peruvian species, e.g. here. Other parts of Bas’ thesis will surely also be inspirational during future work.
More information can be found here (at the time of writing offline, but check as he promises to be back a.s.a.p.). Anyhow, proficiat Dr Bas!
Reference:
B. Kokshoorn, 2008. Resolving riddles and presenting new puzzles in Chondrinidae phylogenetics. Leiden, Ph.D. thesis: 1-188.
The thesis consists of eight chapters of which several will be published later in peer-reviewed journals. I mentioned already the chapter on prime and remnant species. Other chapters deal with an introduction to the family Chondrinidae, the historical biogeography of the genus Chondrina, a phylogenetic analysis of the Abida secale-complex and its ecophenotypic variation and finally a taxonomic revision of the Chondrinidae.
In the discussion I found the part on the altitudinal gradients and shell morphology particularly interesting. To what extent is selection expressed when comparing samples collected on different mountain transects? Also the factors explaining the variation were discussed. The methodology applied may be applicable to some questions I have about some Peruvian species, e.g. here. Other parts of Bas’ thesis will surely also be inspirational during future work.
More information can be found here (at the time of writing offline, but check as he promises to be back a.s.a.p.). Anyhow, proficiat Dr Bas!
Reference:
B. Kokshoorn, 2008. Resolving riddles and presenting new puzzles in Chondrinidae phylogenetics. Leiden, Ph.D. thesis: 1-188.
Good heavens!
02-12-2008 14:41
The paper of Cowie et al., mentioned in
my post
of yesterday, even appears to have attracted
editorial attention. Quite a milestone (or do you
have more examples of editorial notes on snails and
slugs?).
In the same newspaper the potential risk of invasive molluscs was made the issue of the day, under the heading “State ineffective as snails and slugs sneak in”:
Fending off alien plants and animals is a constant, uphill battle in Hawaii but it must be sustained for the health of the agricultural industry and the tourism economy as well as the native environment.
Limited funding, manpower and political will have left the islands porous to harmful species. The state needs to put together an improved system of checks and inspections, which may cost more up front, but save both businesses and taxpayers the expense and difficulties of eradication or containment.
A recent survey of 40 plant nurseries around the state, conducted by a University of Hawaii at Manoa biosciences research program, found all of them were infested with alien slugs and snails.
Of equal concern was that nursery operators had no idea of the infestations and were moving their products from island to island and elsewhere, possibly spreading the pests.
Five of the 29 alien species discovered had never been reported in Hawaii previously and many had not been reported on particular islands before. Some nurseries unknowingly had as many as 17 invasive species.
The report of the survey in the International Journal of Pest Management comes as the state goes through the annual hit-or-miss exercise of checking imported Christmas trees for pests through eyeballing them and the low-tech method of shaking or pounding evergreens to displace bugs and whatnots.
In some years, the holiday trees, mostly from the Pacific Northwest, have arrived with wasps and other insects and been turned away. In others years, lizards and snakes have escaped officials' notice, much to the alarm of the residents who found them in their homes.
This year, slugs have made appearances, which Robert Cowie, a snail-slug specialist at the university who also was involved in the survey, described as "potentially quite serious pests." Though the environmental risks aren't known, some of the infested nurseries were supplying plants to restore native habitats in particularly vulnerable places like Kahoolawe.
The slugs and snails could also prove damaging to vegetables such as lettuces and cabbages, specialty fruits and floral crops.
The survey found a pattern for the gastropods among the nurseries - arriving first on Oahu, escaping to establish themselves around the island, then being transported to neighbor islands through horticultural traffic.
Cowie suggests the state study horticultural distribution networks to find a way to put controls at key points. That could be productive, but the state should take a comprehensive look at how it could best intercept invasive and alien species, much as California and other states head off island produce for fruit flies
I just can’t imagine that the responsible civil servants will be happy about this editorial. And maybe some politicians are becoming a bit itchy too. Usually they are up to defend any activity that brings in money and jobs. After all snails and slugs don’t vote....
Thanks again, Carl!
In the same newspaper the potential risk of invasive molluscs was made the issue of the day, under the heading “State ineffective as snails and slugs sneak in”:
Fending off alien plants and animals is a constant, uphill battle in Hawaii but it must be sustained for the health of the agricultural industry and the tourism economy as well as the native environment.
Limited funding, manpower and political will have left the islands porous to harmful species. The state needs to put together an improved system of checks and inspections, which may cost more up front, but save both businesses and taxpayers the expense and difficulties of eradication or containment.
A recent survey of 40 plant nurseries around the state, conducted by a University of Hawaii at Manoa biosciences research program, found all of them were infested with alien slugs and snails.
Of equal concern was that nursery operators had no idea of the infestations and were moving their products from island to island and elsewhere, possibly spreading the pests.
Five of the 29 alien species discovered had never been reported in Hawaii previously and many had not been reported on particular islands before. Some nurseries unknowingly had as many as 17 invasive species.
The report of the survey in the International Journal of Pest Management comes as the state goes through the annual hit-or-miss exercise of checking imported Christmas trees for pests through eyeballing them and the low-tech method of shaking or pounding evergreens to displace bugs and whatnots.
In some years, the holiday trees, mostly from the Pacific Northwest, have arrived with wasps and other insects and been turned away. In others years, lizards and snakes have escaped officials' notice, much to the alarm of the residents who found them in their homes.
This year, slugs have made appearances, which Robert Cowie, a snail-slug specialist at the university who also was involved in the survey, described as "potentially quite serious pests." Though the environmental risks aren't known, some of the infested nurseries were supplying plants to restore native habitats in particularly vulnerable places like Kahoolawe.
The slugs and snails could also prove damaging to vegetables such as lettuces and cabbages, specialty fruits and floral crops.
The survey found a pattern for the gastropods among the nurseries - arriving first on Oahu, escaping to establish themselves around the island, then being transported to neighbor islands through horticultural traffic.
Cowie suggests the state study horticultural distribution networks to find a way to put controls at key points. That could be productive, but the state should take a comprehensive look at how it could best intercept invasive and alien species, much as California and other states head off island produce for fruit flies
I just can’t imagine that the responsible civil servants will be happy about this editorial. And maybe some politicians are becoming a bit itchy too. Usually they are up to defend any activity that brings in money and jobs. After all snails and slugs don’t vote....
Thanks again, Carl!
Horticultural trade as vector for snail pests
01-12-2008 16:29
Carl Christensen just draw my attention to a paper by
Robert Cowie et al., on which a popular article
appeared in a
local
newspaper.
Having inventoried 40 horticultural nurseries on different islands in Hawaii, Cowie and his team come to the conclusion that horticultural trade has spread invasive snails and slugs which are potentially serious pests. Many nurseries visited in Hawaii didn’t know that they were infested by snails and slugs - e.g. because they were too small to become readily noticed - and thus inadvertently exported them.
While the article describes the situation found and the conservation issues in Hawaii, one can think of analogous situations in horticulture nurseries elsewhere, not to mention snail nurseries. There will be a paper on the side effects of the latter in the next issue of Tentacle.
Reference:
Cowie, R.H, Hayes, K.A., Tran, C.T. & Meyer, W.M., 2008. The horticultural industry as a vector of alien snails and slugs: widespread invasions in Hawaii. - International Journal of Pest Management 54: 267-276.
Having inventoried 40 horticultural nurseries on different islands in Hawaii, Cowie and his team come to the conclusion that horticultural trade has spread invasive snails and slugs which are potentially serious pests. Many nurseries visited in Hawaii didn’t know that they were infested by snails and slugs - e.g. because they were too small to become readily noticed - and thus inadvertently exported them.
While the article describes the situation found and the conservation issues in Hawaii, one can think of analogous situations in horticulture nurseries elsewhere, not to mention snail nurseries. There will be a paper on the side effects of the latter in the next issue of Tentacle.
Reference:
Cowie, R.H, Hayes, K.A., Tran, C.T. & Meyer, W.M., 2008. The horticultural industry as a vector of alien snails and slugs: widespread invasions in Hawaii. - International Journal of Pest Management 54: 267-276.
Ancient snail art
01-12-2008 07:26
Snails have an ancient track record as object of art.
Here are some photos from objects found in northern
Peru, dating back to the
Moche culture
(ca. 400 AD).
The photos were kindly supplied by Edward de Bock.
The photos were kindly supplied by Edward de Bock.