30 September 2007
28 September 2007
I occasionally review on this blog papers that are several notches below the standard quality of a scientific paper, including some that should never have been published. There is one example in this post.
This edition is about a paper by Carsten Renker, titled "Genetic break in Lauria cylindracea..." and published this year in the Archiv für Molluskenkunde, vol. 136, pp. 1-7.
Lauria cylindracea is a rather small land snail. It appears to be somewhat variable in the dimensions and morphology of its shell. So, there is a possibility that there may be cryptic species within the group of snails loosely identified as Lauria cylindracea. To evaluate that possibility, which was a great idea, Renker studied 20 samples of L. cylindracea from various locations in Europe, including, Great Britain, Germany and Greece. He compared the sequences of nuclear ribosomal DNA and shell dimensions of the samples.
I am not qualified to judge the DNA part of the study. I am, however, very critical of the way shell dimensions were analyzed and reported in the paper.
The fatal flaw is that Renker compared the means of the 20 samples using multiple t-tests. Even the most elementary statistical courses and books warn the students that they should not use the t-test for multiple comparisons of more than 2 samples. That's because, without going into details, multiple t-tests increase the chances of getting a statistically significant result just by coincidence. The accepted and standard procedure for comparing more than 2 samples is the method known as the analysis of variance (ANOVA). But apparently, neither Renker nor the 2 anonymous reviewers were aware of this fact. (Here is a brief discussion of the t-test versus ANOVA and here is another one.)
All Renker says about the results of the tests is this: "...shells collected in German populations were generally slightly taller (p<0.001) than shells from other countries (Fig. 1)."
First, this is not how one reports the results of multiple comparisons. I would like to know which German samples were "slightly taller" than which of the other samples. Figure 1 from the paper reproduced below shows that there was quite a bit of scatter and overlap in the distributions of the sample means and 2 German samples (marked by the letter D) are positioned among the samples from other countries. Second, Renker's one sentence summary is a meaningless statement. What does "generally slightly taller" mean? It means nothing. There may indeed be statistically significant differences between the means of some of the samples, but no reliable evidence is given in this paper that they are.
The above figure from the paper is a bivariate plot of shell length versus shell width. The markers denote the positions of sample means and the bars are the standard deviations. In a plot like this it would be more meaningful to show, not the standard deviation, but the extent of the standard error of each mean. Since Renker does not give sample sizes either, there is no way to estimate the confidence intervals of sample means from the standard deviation values.
Another problem: Renker states that "Morphological data were tested for normal distribution with the Kolmogorov-Smirnov test." But he does not say if the data were normally distributed. Stating that a test was done is not helpful unless the results are also given. Since the t-test was used, we can only assume that the distributions were normal.
I am disappointed that Archiv für Molluskenkunde published this paper. If I had been a reviewer, I would have rejected it.
Posted by AYDIN ÖRSTAN at 16:48
27 September 2007
Deniz The Niece who is my niece now has her own blog, The Girdle of Melian. Deniz has been an occasional commenter on Snail's Tales and this post featured a picture of her that I had taken during a snail collecting and sight seeing trip the 2 of us had taken thru some cemeteries and winding streets lined with old houses in Istanbul in 2002.
Deniz lives in Montreal with one husband, 2 cats and several thousand books. She knows English, French, Turkish and probably some other auxiliary languages. Deniz, unlike me, is a native English speaker (she moved to Canada from Turkey before she uttered a single meaningful word) and so naturally is the person I frequently turn to (via e-mail) when I am stuck with a poorly constructed sentence.
A week from now I will be in Montreal for an extended weekend and hopefully will get together with her and the rest of the family.
Posted by AYDIN ÖRSTAN at 21:46
It has come to my attention that prospective readers attempting to download my 2 chapters from the Mollusks book, the availability of which was announced in this post, have been getting the following error message from Earthlink:
Sorry...Page Temporarily Unavailable
The Web page or file that you requested is temporarily unavailable. It has been so popular this month that it exceeded its free monthly traffic allotment. Access to this Web site will be restored on the first of next month. Please come back then.
The very same problem is also making the photographs in my older posts unavailable. I am trying to remedy the situation by moving the photographs to my Flickr page. However, that is easier said than done, for not only do I have to move the pictures, but I also have to copy and paste a new link for each one and then republish each post. But all the photographs will be restored eventually.
I have no other place to move the book chapters. So, if you want to download them, please try again in October. We thank you for your readership.
Posted by AYDIN ÖRSTAN at 08:20
26 September 2007
The snails in the genus Truncatella appear to have evolved from marine ancestors to become terrestrial relatively recently on the geologic time scale. They have not ventured far from their ancestral home, for most species still live right at the edge of the sea where they frequently get covered by the waves. They were the subjects of 2 previous posts here and here.
There are several species in the genus and more research about their ecology and biology will certainly lead to a better understanding of how marine snails first became terrestrial. For whatever reasons, however, not many malacologists have been interested in them.
One malacologist who studied the Truncatella species of Florida and the Caribbean for his PhD thesis back in the late 1960s was Landon Ross. In a recent e-mail, he explained that as soon as he got his PhD in 1969 he switched to environmental science and never published anything from his dissertation. His only published contribution to the study of Truncatella was a short note: Ross, L.T. 1969. Notes on the life history of Truncatella caribaeensis. American Malacological Union Annual Reports for 1969 pp. 35-36.
Landon Ross just put up his entire dissertation on the Internet. It is a 25 MB pdf file, but worth downloading, if you are interested in Truncatella, because there is a lot of useful information not available elsewhere. However, be careful with the taxonomy, because getting the identities and the correct names of some of the species is tricky. Consult the following for more recent information: Rosenberg, G. 1996. Independent evolution of terrestriality in Atlantic truncatellid gastropods. Evolution 50:682-693.
Posted by AYDIN ÖRSTAN at 17:27
25 September 2007
I found this dead moth this afternoon along a staircase in the Metro station at College Park, Maryland. It appears to be a species of Apantesis (Noctuoidea, Arctiidae).
The orange color on the hindwings is visible thru the gap between the forewings.
The previous train station lepidopteran featured on this blog was a common buckeye (Junonia coenia).
Posted by AYDIN ÖRSTAN at 23:00
A reader left this comment at one of last week's posts:
I've just come across your blog and though I'm more of a palaeontology afficando, I find myself really wanting to learn more about snails. But I really have no idea where to start. Do you have any book or website recommendations for a non-expert on snails?
If you want to learn more about snails, read Snail's Tales!
There really are no recent, good technical books on snails suitable for beginners with a scientific background. Nevertheless, you may want to take a look at the following:
G.M. Barker, editor. 2001. The Biology of Terrestrial Molluscs.
Overpriced! Check it out from a library and photocopy it! There are no excuses in this case. Otherwise, there are some good articles, but they may be difficult to follow for someone with no relevant background.
Geerat J. Vermeij. 1993. A Natural History of Shells.
It is almost entirely about the evolutionary aspects of shell structure and construction pertinent to marine mollusks and being so it won't teach you much about the mollusks' soft parts or their biology or terrestrial gastropods.
Alan Solem. 1974. The Shell Makers - Introducing Mollusks.
Although it is old and somewhat outdated, it still is a useful source. But beware of Solem's many debatable speculations!
Sturm, Pearce and Valdés, editors. 2006. The Mollusks.
This book will teach you mostly about various techniques useful to collect and study mollusks. My review of it is here.
Moore, Lalicker & Fischer. 1952. Invertebrate Fossils.
Chapter 8 is about gastropods. Although it is more than 50 years old, there is good, basic information about shell morphology with emphasis on fossils, although some of the taxonomy is undoubtedly out of date. Nevertheless, this may be a good starting point for a palaeontologist, but, again, there is very little biology and anatomy.
I recently noticed the lack of a good introductory technical book on terrestrial gastropods and started writing one myself. It will be a while before it gets published, though. But, in the meantime, allow me to repeat, if you want to learn more about snails, keep reading Snail's Tales!
Posted by AYDIN ÖRSTAN at 14:40
24 September 2007
Ever since our 1988 Toyota reached its 150,000th mile in July, we've been pondering and at the same dragging our feet about buying a new car. When late Saturday afternoon the Toyota suddenly developed a radiator leak and started dripping some green fluorescent fluid all over the driveway, I decided that it was time to pull the plug. My neighbor tried to persuade me that I could probably get the radiator fixed for about "150 bucks". But I countered him that soon something else would break. He then suggested something called Bar's Leaks brand "Liquid Aluminum Radiator Stop Leak" to repair the leak in the radiator temporarily-at least until I drove the car to a car dealer. So I got a bottle of Bar's Leaks brand "Liquid Aluminum Radiator Stop Leak", shook it hard, emptied it into the radiator and the leak miraculously stopped (Saint Che loves me!).
Sunday morning I drove to the nearest Toyota dealer and bought a brand new 2008 Toyota Yaris. Color? Bayou Blue.
We saved nickels, we saved dimes, we worked till the sun don't shine and bought a bayou blue car. That would make a good song, wouldn't it?
The folks at Toyota must like the late great Roy Orbison.
In case you are wondering, the Toyota dealer gave me $50 for my old car. If I had told them about the radiator, they probably would have charged me a disposal fee.
Posted by AYDIN ÖRSTAN at 14:59
23 September 2007
O Saint Che, send more visitors to this blog. Amen.
On 9 October of this year, it will be 40 years since the Marxist revolutionary Ernesto "Che" Guevara was killed in La Higuera, Bolivia. The Guardian reports that in the Bolivian town of Vallegrande, where Che's body was displayed, he has achieved the status of a deity:
"In this region, images of Che hang next to images of Jesus, the Virgin Mary, Pope John Paul II and Bolivia's President Evo Morales. Stories of miracles have mushroomed."
Susana Osinaga, a nurse who cleaned Guevara's body, claims that Che "is very miraculous." But it isn't just the old timers who worship him. This is what the 27-year old Freddy Vallejos had to say:
"We have a faith, a confidence in Che. When I go to bed and when I wake up, I first pray to God and then I pray to Che - and then, everything is all right."
This is a fine example of how saints, deities, gods and religions, for that matter, have always been created. Under slightly different circumstances, Che could have turned into a major god with his own holy book easily replacing all other gods that came before him.
Who is to claim in his sane mind that this is not how it happened after some guy was supposedly crucified 2000 years ago?
The corollary to this story is that all gods are false; all gods are figments of their believers' imaginations.
Photograph of Che from here.
Posted by AYDIN ÖRSTAN at 17:05
22 September 2007
A movement of some sort against the use of disposable plastic bags seems to have started over in the United Kingdom, according to this article in today's edition of the Guardian. Apparently, many stores and towns have banned or considering banning the use of disposable plastic bags. Modbury claims to be the first town in the UK to be "plastic bag free". I hope they will keep up with it.
Over here on this side of the Atlantic, the large grocery stores I shop at give a small credit, usually 3-5 cents per bag, when the customers bring their own bags, whether they are paper or plastic. For the last 3 years or so we've been putting our groceries into reusable bags whenever we shop at the Whole Foods Market (or at other stores). The initial cost of the bags was something like $2/bag. I shop there almost every weekend. So, the use of reusable bags starts profiting the earth almost immediately and the 5 cents/bag credit the Whole Foods gives starts profiting the customers after a year.
Plastic bags used once and then thrown away waste resources and pollute the environment, not just on land but also in the oceans. Would you consider switching to reusable bags for the sake of our earth?
Reusable bags filled with all sorts of goodies.
Posted by AYDIN ÖRSTAN at 12:02
21 September 2007
Our beloved fluffy Temi has turned 19. She is doing great for her age, although she may be losing her hearing and getting cataracts in her eyes. She still likes to go out to the backyard to eat grass and to sit around. She can't run anymore, but can still go up and down the stairs, albeit slowly. And she spends most of her time sleeping, but then again, which cat doesn't?
Way to go Temi!
Posted by AYDIN ÖRSTAN at 22:35
20 September 2007
A totally blind process can by definition lead to anything; it can even lead to vision itself.
Jacques Monod, Chance & Necessity, 1972
What you can do with ANOVA
Once it is understood, analysis of variance is a tool that can provide an insight into the nature of variation of natural events, into Nature in short, which is possibly of even greater value than the knowledge of the method as such.
R.R. Sokal & F.J. Rohlf, Biometry, 3rd ed. 1995
Why I am always right
I feel that scientific creativity is rooted in the inner tension, within one and the same person, of knowing that he or she is right and knowing that that conviction has to be proven to the satisfaction of others-in a journal article.
Roald Hoffmann, The Same and not the Same, 1995
So much for poetry
Through a poet's eyes, we see the superficialities of events...But through a scientist's eyes, we penetrate the surface and see the spirit within.
Peter Atkins, Galileo's Finger, 2003
Entropy of birding
Science, it has been said, begins in observation. The best way to become acquainted with birds, for example, is to look at some birds. A good way to become acquainted with entropy is to look at some entropies.
Henry A. Bent, The Second Law, 1965
Posted by AYDIN ÖRSTAN at 22:03
19 September 2007
This is what a typical jar of delicious almond butter looks like when what is left behind is too frustrating to remove for practical purposes. Throwing this glass jar in the garbage is a waste of resources, attempting to clean it, on the other hand, is a waste of time and water. Luckily, there are chipmunks in my backyard who are more than willing to clean jars like this while getting their nutrition. So the solution that makes everyone happy is to place the jar near a known chipmunk hang-out, which happens to be under the steps leading down from the deck.
Here is the same jar 6 days later.
It was almost sparkling clean except for a few bits of pine needles and a single "example" of what seems to be chipmunk poop.
The chipmunks are happy and the jar is now ready for the recycling bin.
Posted by AYDIN ÖRSTAN at 19:40
18 September 2007
During a recent lunch hour expedition I discovered this wall of graffiti overlooking a narrow field of grass. Burnt plant remains and melted plastic garbage indicated that there had been a small fire in the area not too long ago. To my amazement, there were also hundreds of snail shells covering the ground.
Today I spent about an hour there picking up most every shell I saw. The majority belonged to a yet-to-be-identified Triodopsis sp. Afterwards, a rough count estimated the total number collected as close to 300. I will probably go back and look for more. I am sure there are additional shells under the debris and in the nooks and crannies along the wall.
Many shells had been blackened by the fire. I did not see any live snails. But I can't tell if the fire was responsible for the deaths of the snails. There were also several fresh shells with no fire damage. Those may have belonged to snails that died after the fire destroyed the plant cover.
And 2 shells from the bottom of the wall had received their share of the graffiti artist's paint. This appears to be a good choice of paint to mark snail shells.
*Graffitize is apparently not a word in the dictionary. There are a few examples of it on the Web, though.
Posted by AYDIN ÖRSTAN at 18:10
17 September 2007
The land snail Paramastus spratti, endemic to south-central Turkey, is in the family Enidae. Unlike some other endemic enids, however, this one is somewhat rare and is known only from a few spots.
Adult shells are about 20 mm in height. In the lot of 138 shells that I was measuring the other week, there were only 2-and this was one of them-that still had their yellowish brown periostracum. Most empty shells one is likely to encounter are chalk-white like the one pictured below.
This picture shows the columella of P. spratti in the shell's body whorl. Some enid species, especially those that develop a lamella on their columella that is visible in the aperture, have a twist in their columella within the body whorl. Paramastus spratti, which lacks any prominent lamellae or "teeth" in its aperture, has a straight columella.
Some of the previous entries in the land snails of Turkey series:
Posted by AYDIN ÖRSTAN at 12:05
15 September 2007
I saw this caterpillar while taking a walk in the woods near my house yesterday. I didn't have a container with me so I resorted to the ol' on-my-head-under-the-hat method of carrying insects. The caterpillar, which was a little longer than 4 cm, behaved itself for about a half an hour and didn't do anything nasty to my scalp.
This is a caterpillar of the butterfly spicebush swallowtail (Papilio troilus). According to Wagner (Caterpillars of Eastern North America, Princeton Field Guides, 2005), the caterpillars, normally green, turn yellow or orange when they are ready to pupate. The color of this particular individual was very striking. It is now back in the woods and will hopefully turn into a butterfly one day.
Posted by AYDIN ÖRSTAN at 15:34
14 September 2007
Today I ran into one of my neighbors from down the street whom I hadn't seen in a long time. Years ago we used to ride the bus together on the way home from work. At that time he was working for a company that was developing some software for the State Department to track down unwanted aliens, although what exactly my neighbor did wasn't clear (he now works as a security guard somewhere else).
Our encounter today reminded me of the day when we were sitting next to each other on the bus and he was telling me about his company. Our mutual misunderstanding of words resulted in the following conversation (this was years before 9/11).
He: The software will help the immigration guys keep the terrorists out.
Me: Why do they want to keep the tourists out?
He (perturbed): Why would you want terrorists in our country?
Me (puzzled): What's wrong with tourists?
He (frustrated): Don't you know what a terrorist is?
Me (annoyed): Of course I know what a tourist is!
Eventually, we sorted it out.
Posted by AYDIN ÖRSTAN at 17:05
13 September 2007
It's been 50 years since Jean Lindenmann and Alick Isaacs published their papers on the discovery of interferon, an anti-viral protein manufactured by virus-infected cells. Their research was done at the National Institute for Medical Research (NIMR) in London. In today's Nature, there is a 1-page interview with the Swiss scientist Lindenmann, now 83.
I started out studying physics at the University of Zurich, but 18 months into my course the atom bomb was dropped on Hiroshima. This so disenchanted me that I switched to medicine.
A petition was circulated [at NIMR] to protest the British invasion of Egypt that had nationalized the Suez Canal. But I felt that I shouldn’t sign it because Switzerland was a neutral country.
The fever that the [ferrets infected with influenza] developed could be passed on to other ferrets. In the course of such a passage, a ferret sneezed into the face of [Wilson] Smith, who fell ill with influenza.
Interferon was hyped shamelessly at some phases of scientific research. Of course it never became a miracle cure for cancer and viral infections. Scientists were not innocent in this hyping — it was a way of getting research money.
Posted by AYDIN ÖRSTAN at 21:02
12 September 2007
I like to alternate between English and Turkish books, sometimes within a half hour train commute. I refer to it as taxing my brain and have a vague notion, although without any data to back it up, that switching between texts written in different languages may help keep one's mind sharp. If I knew a 3rd language, I would add that to my reading schedule too.
For about 2 years now I have been ordering Turkish books from Pandora, a bookseller based in Istanbul. Although shipping costs are sometimes as expensive as the books themselves, Pandora's service has so far been reliable. They also have a store in Istanbul, which I visited when I was there last May. It was disappointingly small, but the employees were very helpful and they had the books I was looking for.
Even though I already have a shelf-long backlog of both English and Turkish books to read, I couldn't resist the urge to order more books from Pandora less than 10 days ago. They arrived today despite the fact that they were shipped by surface mail.
The new additions to the backlog are a small book about the structure of scientific thinking during the Ottoman period, the latest issue of a literature magazine featuring several cat (kedi) stories and another book about the history of the Greek residents of Büyükada (Prinkipo), one of the islands off Istanbul. I have written about Büyükada in this post and in this post and in this post.
Posted by AYDIN ÖRSTAN at 17:56
11 September 2007
Last week I wrote about what appeared to be the ruins of a house in a wooded area near where I work. The topo map showed at least 3 roads that were once present there. One nameless road, identifiable from short segments of a concrete surface at a couple places, coincides with the narrow path that crosses the area (see the satellite photo in the previous post).
Map from TopoZone.
A few days later, I went back to search for Oberlin Road shown on the map. It turned out that the south half of that road had been obliterated by the overgrowth of miscellaneous plants. So I wondered around for a while under the trees not knowing exactly where I was. Along the way, I discovered 2 or 3 more ruins of foundations of buildings similar to the one identified in the previous post.
Eventually, I ended up in a wide overgrown path surrounded by trees along both sides. I suspected I was on the right track and kept on pushing thru the densely intermingled plants. Then suddenly, a concrete surface appeared in front me: Oberlin Road.
A reader, in her comments to the previous post, identified the ruins as those of the buildings that once housed the workers of the nearby and now-closed Engineering and Research Corporation (ERCO) plant. The area is now known as the Cafritz property and not too surprisingly, is slated for development. As if what we needed was more houses in a neighborhood already full of houses, the recovering trees will be cut down, the other plants will be cleared and houses will be built in their places. Despite the upscale image they are attempting to create for the planned development at the web site, I very much doubt that it is going to look like that; they are surrounded by noisy railroad and Metro tracks on one side and some commercial buildings and a non-existent town center on the other.
It would make more sense to me if the area was instead joined to the existing small park to the north. What we need more is green space.
Posted by AYDIN ÖRSTAN at 14:03
10 September 2007
What with the winter approaching, the end of October may be a little too late for a northern hemisphere mollusk to ovulate, but it is never too late to have a meeting about mollusks.
The first annual one-day meeting of the Ohio (River) Valley Unified Malacologists (OVUM), organized by Tim Pearce and Charlie Sturm, will be at the Carnegie Museum of Natural History in Pittsburgh, PA on Saturday, 27 October 2007 from 10AM until the last presentation (to end by 5PM at the latest).
The meeting is open to professionals, amateurs, and students; basically anyone who has an interest in mollusks. OVUM has no dues, officers, abstracts, or publications. This is as casual as a scientific meeting can get. If you are working with mollusks, this is a good opportunity to present a short update of what you've been up to lately and pass some ideas around; if you are interested in mollusks, but don't know much about them, this will be a perfect chance to get yourself initiated into the wonderful world of snails, slugs and the 8-armed octopuses.
From the e-mail announcement:
Light refreshments such as fruit, bagels, coffee, tea, and water will be available from 9-10:00AM. The meeting will be in the American Indian Room on the third floor of the Museum...
Presentations should be limited to 15 minutes. A computer projector and overhead projector will be available. Presentations are encouraged from amateurs, professionals, and students. Presentations are informal and can cover any topic relating to mollusks. Current research, a recent collecting trip, or an interesting specimen are all likely topics for a presentation. You can notify us ahead of time or the morning of the meeting if you would like to speak on some topic.
At noon, we will break for lunch. There are numerous restaurants within walking distance of the Museum as well as within the Museum. A list of restaurants will be made available the day of the meeting. Information on local hotels can be obtained from Charlie Sturm.
The collection and/or library of the Section of Mollusks will be available after the presentations are concluded. Those interested in availing themselves of these opportunities should contact Tim Pearce (PearceT AT CarnegieMNH DOT org; phone 412-622-1916) or Charlie Sturm (csturmjr AT pitt DOT edu) in advance.
If you have any questions regarding the meeting or the Carnegie Museum, please contact Charlie Sturm.
I plan to go.
Posted by AYDIN ÖRSTAN at 09:54
09 September 2007
An animal, a slug maybe, had violated the integrity of this backyard tomato by opening up a hole on top of it. I took advantage of this portal to the inner universe of the tomato by conducting a little experiment in tomato calorimetry.
The results conclusively demonstrate that tomatoes exposed to full sun could get rather hot. At 1500 hours yesterday afternoon this tomato had an inside temperature of 44°C.
Next project from the dull edge of science: a lentil mystery.
Posted by AYDIN ÖRSTAN at 11:08
08 September 2007
07 September 2007
This isn't exactly beer, but fermented apple cider with 6% alcohol. It is yellow, cloudy, sweet and tastes like, well, apple cider. Oh yes, it is organic, if that matters. Although I enjoy slightly sweet beers, I'd prefer my hard cider a bit less sweet.
J.K. Scrumpy's Hard Cider comes from Michigan. The company's web site is here, but as is the norm with such sites, there is little useful information.
Posted by AYDIN ÖRSTAN at 17:33
06 September 2007
*Defiance of copyright laws is so much fun. Evil laugh
**K.M. Wrinn and G.W. Uetz. Impacts of leg loss and regeneration on body condition, growth, and development time in the wolf spider Schizocosa ocreata. Can. J. Zool. 85:823–831 (2007).
Posted by AYDIN ÖRSTAN at 19:40
05 September 2007
It is good to go off the beaten paths every now and then. A couple of weeks ago during my lunch break, I was exploring an area that I had recently "discovered" not too far from where I work. I was on a narrow unpaved path, the "main artery" that crosses the wooded lot when I came to a fork going to the right and which I had ignored in the past. That day I decided to go that way.
About 100 m later, I came to a sort of clearing in the woods where the ground was slightly elevated and surrounded by a narrow concrete border. There were chunks of concrete littering the ground.
The peculiar thing about these slabs of concrete was that they had pebbles embedded in them. While searching for snails during a later trip to the same spot, I discovered that the thin accumulation of leaf litter at the surface was hiding a thick layer of pebbles underneath, the kinds you would find at a beach or along a creek.
I suspect there was once a house here.
As the recent satellite picture from Google Earth shows, the general area is surrounded by residential streets to the north, industrial buildings to the south, railroad tracks to the east and a busy road to the west.
The yellow marker is the approximate location of the house ruin.
It is surprising that this parcel of land has escaped development so far. However, the trees are quite young; they may have been growing for only about 20 years or so. Furthermore, the outdated topographic map shows a Woodbury Street and an Oberlin Road that are not there anymore. You can still see the faint outlines of those streets on the Google Earth picture. The topo map doesn't show the area as being wooded (it would have been green). So it appears that this area didn't use to be as "wild" as it is now (I saw a deer there on another trip). However, the topo map doesn't show any houses despite the labelled streets.
Map from TopoZone.
And yes, I did find snail shells there but that's for another post.
Posted by AYDIN ÖRSTAN at 18:25
04 September 2007
I just uploaded the pdf versions of the 2 chapters I contributed to The Mollusks, edited by Sturm, Pearce and Valdés.
Pearce, T. & Örstan, A. 2006. Terrestrial gastropoda, Chapter 22 in C. Sturm, T. A. Pearce & A. Valdés, editors, The Mollusks: A Guide to Their Study, Collection, and Preservation.
Örstan, A. 2006. Rearing terrestrial gastropoda, Chapter 23 in C. Sturm, T. A. Pearce & A. Valdés, editors, The Mollusks: A Guide to Their Study, Collection, and Preservation.
Download them and read them.
Posted by AYDIN ÖRSTAN at 20:48
I found this caterpillar on a path in the woods near my house yesterday. It was alive, but just lying there to be run over by a bicyclist or a runner. It didn't object too vigorously to being picked up with a leaf and carried to my backyard.
It looked like there was some black encrustation around the caterpillar's body behind its head. During the photo session, a wasp got interested in the caterpillar and kept landing on the encrusted parts. I don't know what the deal was.
After the photo session I placed the caterpillar in a secluded place in my yard. When I checked on it about an hour later, it wasn't there anymore.
Later, a quick search thru the caterpillar pictures on BugGuide revealed that this was a Hickory Horned Devil, the caterpillar of the Royal Walnut Moth (or Regal Moth, Citheronia regalis).
Posted by AYDIN ÖRSTAN at 09:07
03 September 2007
01 September 2007
The huge and pretty Australian land snail Hadra bipartita was the subject of a recent post at A Snail's Eye View. These snails can grow up to a rather respectable shell diameter of 68 mm.
In stark contrast, tonight I was measuring a tiny, tiny snail, Vertigo pygmaea from my backyard. At least 2 times a year, I collect all the live adults I can find, measure their shells and then return them to the yard. The sample averages are about 1.8-1.9 mm (details here and here).
Usually once a year I also mark* the shells of a number of snails. That helped me determine that adult snails can survive the winter (details here). The last time I marked some snails was on 25 December 2006 when I used red ink on 20 adult snails. To my surprise, one of the 12 adults I found today had a red mark on its shell. Prior to last December, I had used red ink also in March 2006. I will assume that an ink mark on a shell would not last that long. Therefore, the marked adult found today was probably marked last December and has been alive as an adult for at least 8 months.
Those dots in the container under the microscope are the snails I measured tonight.
*I have been using various colors of Pigma Micron pens. The ink survives on snail shells for at least 3 months. In the case of one of the snails collected today, the ink was visible after 8 months.
Posted by AYDIN ÖRSTAN at 22:43