31 July 2009

Orange and yellow fungus

About 24 cm from left to right.

It was growing on dead wood.

The previous fungus post was here.

30 July 2009

Hummingbird clearwing


This morning's excitement was this moth hummingbird clearwing (Hemaris thysbe). I was standing at the kitchen window waiting for my coffee when I spotted it flying around the honeysuckle bush covering our mailbox. Luckily it was still there when I came out with the camera a few minutes later.

These moths are difficult to photograph. The picture above was at a shutter speed of 1/125 and the wings—because they beat so fast—are just a pair of blurs. There wasn't enough light for a faster shutter. The result was a bit better after I switched to flash with a shutter speed of 1/160 s. Notice that the moth seems to be supporting itself on the leaves and the petals with its legs.


The red arrow is pointing at the unrolled proboscis entering into the honeysuckle flower. This is probably the Japanese honeysuckle, an alien species. According to this site, it is one of the "least wanted" introduced plants. Heck, native moths feed on it, native bees feed on it. I don't see anything wrong with that and mine is staying.

29 July 2009

Survival at extreme temperatures: what is it good for?


JOHAN MERTENS, LYNDA BELADJAL, ANGELICA ALCANTARA, LIESJE FOUGNIES, DOMINIQUE VAN DER STRAETEN and JAMES S. CLEGG (2008). Survival of dried eukaryotes (anhydrobiotes) after exposure to very high temperatures Biological Journal of the Linnean Society, 93, 15-22 pdf

Ever since Antonie van Leeuwenhoek demonstrated the appearance of animalcules* in cultures made with previously dry dust more than 300 years ago, biologists have been getting kicks out of pushing the limits of the survivability of dried animals and plant seeds. This is one of those studies the object of which seems to have been to demonstrate how high a temperature certain organisms can survive—regardless of whether or not the results had any biological significance.

Mertens et al. showed that the seeds or spores of various plants (Cardamine, Taraxacum, Adiantum, etc.), the cysts of the crustaceans Branchipus schaefferi (fairy shrimp) and Artemia franciscana (brine shrimp) as well as adult bdelloid rotifers and tardigrades survived exposures to temperatures as high as 130 °C for as long as 10 min.

The trick was to desiccate the seeds, spores and the animals first (for 3 days over silica gel) before heating them slowly at a rate of 4 °C per minute. However, the bdelloid Philodina did survive exposure to 120 °C even when it was heated rapidly (100 °C/min).

This is all very interesting, but what exactly do these results mean considering that these organisms are unlikely to experience such high temperatures in their habitats except perhaps during wild fires? The authors try hard to come up with a speculative scheme to explain how the ability to tolerate high temperatures could have arisen during the Devonian or earlier when the earth was supposedly a warmer place—but not that warm. But this doesn’t explain how adaptations to survive temperature extremes unlikely to be encountered in the organisms’ present or Devonian habitats arose to begin with.

Such extreme over-adaptations are likely to be the unintended byproducts of moderate over-adaptations to environmental stresses likely to be encountered occasionally. If desiccated rotifers and tardigrades or the seeds and spores of various plants are routinely exposed to temperatures around 40 °C, then those individuals that have evolved to incorporate a safety factor into their adaptation that makes them survive slightly higher temperatures, say 50 °C, will fare better in the long run when and if the habitat temperature happens to rise that high. It is likely that the mechanism that confers protection at 50 °C also protects at much higher temperatures that the animals will never experience as long as the cost of maintaining such a mechanism for occasional use is not too expensive.

*Leeuwenhoek’s animalcules were probably bdelloid rotifers, see Tunnacliffe, A. and J. Lapinski. 2003. Philosophical Transactions: Biological Sciences 358:1755-1771.

28 July 2009

An undead tree

Remember this beech tree that had fallen down sometime at the end of last year in the park near my house? I had been assuming since then that it was a dead tree. About 10 days ago I was standing on it (it forms a nice natural bridge over a small creek) when all of a sudden it dawned on me that its "dead" branches were covered with green leaves. Imagine my surprise.


I walked back and forth on the trunk several times to convince myself that the branches with leaves didn't belong to some other nearby tree; they do belong to the tree that is lying more or less flat on the ground.

Even though the main trunk broke, some roots remained intact and buried. Obviously, they are providing enough water and whatever else a tree sucks out of the soil to sustain itself.


I wonder how long it will continue to live like this. I will provide updates.

See this post for an update on the status of this tree.

27 July 2009

Rock solid data


Although there are fluctuations, which are normal and expected, the data are revealing an undeniable downward trend in the index of satisfaction (IS) over time. However, the meaning of this finding is open to interpretation when the definition of IS is taken into account.

index of satisfaction = optimism / happiness

Since increased levels of both optimism and happiness are good, the long-term consequences of an overall decrease in IS are hard to predict at the moment.

Next update.

26 July 2009

Fireflies mating


Early Friday afternoon I stepped outside to get something from the car and saw all these fireflies flying around the front yard. Then I noticed one flashing on the leaf of a small plant with another flashing firefly hovering just a few centimeters above it. When I returned from the car a few seconds later, they had already started mating. I ran inside and returned with the camera a few minutes later and managed to take several shots. 10 minutes later they were still at it.

Is the larger individual on the right the female? Do you notice something odd about it? It was missing its right antenna. A short stump is visible. So, I guess one antenna is enough for a firefly to survive long enough and find a mate to pass on its genes.

I had never seen a male and a female firefly so close to each other communicating with their light signals. So, it does work! Evolution will never fail to impress and amaze me.

24 July 2009

A massacre in the forest


A couple of weeks ago while exploring the park near my house I found this tree with a deep hole in its trunk. Tree holes are usually good places to search for interesting creatures. Sure enough, there were 3 snail shells inside and just outside this hole. Each had its apex removed.


The largest one, an adult, is a Neohelix albolabris. The others are probably juveniles of the same species or juveniles of Mesodon thyroidus (the 2 species are difficult to distinguish before they mature).

Not too far from the 1st tree, at the base of another tree with a partially rotten trunk on one side, I found 7 more shells with similar breakage patterns. The 2 largest ones are again Neohelix albolabris. I suspect these snails had been preyed on by a rodent, perhaps a chipmunk.


On the same tree, about 1.2 m above these shells was a live juvenile snail temporarily dormant on the trunk. Because I could not identify it for certain, I brought it home.


I noticed earlier this afternoon that it had built its adult lip and it is a Mesodon thyroidus, a species that often climbs trees. That would be an effective way to avoid ground based predators*. On the other hand, I don't remember if I've ever seen Neohelix albolabris on trees. And that may explain why most of the predated shells I found appear to belong to the latter species, although the juveniles require a definite identification.

Potential revision alert (26 july 2009): My identification of the snail from the tree as Mesodon thyroidus may have been premature. Apparently the snail has't completed its growth yet and may in fact be a Neohelix albolabris. I may revise this post in a few days.

*Do chipmunks climb trees?

23 July 2009

3 ivies together: poison ivy, Virginia creeper, English ivy

This is the continuation of an earlier post about a poison ivy plant I photographed at the Georgetown University Hospital last week. I took this picture in Rock Creek Park not too far from the hospital on the same day.


On the left is a poison ivy (Toxicodendron radicans) with its characteristics 3 leaves, in the center and to the right is a Virginia creeper (Parthenocissus quinquefolia) with its characteristics 5-leaflet leaves and covering the ground is the English ivy (Hedera helix).

Both the poison ivy and the Virginia creeper are native to eastern North America, but the English ivy is a native of Europe that is now naturalized in many parts of the U.S. It is considered an invasive plant.

As my friend Susan pointed out in her comment to the previous post, the young shoots of the Virginia creeper may have leaves 3 with leaflets, but there are likely to be some leaves with the usual 5 leaflets on the same plant, making the identification easy. The poison ivy, on the other hand, always has 3 leaves. The picture below shows a young Virginia creeper. Notice the leaf with 3 leaflets next to my thumb as well as the 4 and 5 leaflet varieties. As the plant grows, all the leaves acquire the normal 5-leaflet configuration.


Note added later: A few minutes after I posted this post I noticed that the 2 largest leaves of the Virginia creeper in the 1st picture actually have 6 leaflets each.

22 July 2009

Knock 3 times on the elevator if you want help

Photographed inside an elevator at the Smithsonian's National Museum of Natural History today.

Surely there must be a more effective way for deaf people to request help from inside an elevator.

21 July 2009

Free-range snail farming in New Zealand

The reader Andrew Broome from New Zealand recently sent a link to a podcast of a Radio New Zealand interview with the owner of Silver Trail snail farm in Hawke's Bay New Zealand where you can get "hand-harvested gourmet snails".

The snail they are raising is the petit gris, or the little gray, which is a vernacular name for Helix aspersa (Cantareus aspersus, Cornu aspersum, etc.).

If you have 10 minutes to spare, listen to the podcast; it's entertaining. And I hope you'll understand their English better than I have. I think I got most of it, though.

20 July 2009

Miscellanea for 20 July 2009

A Christian friend who also studies snails wrote in a recent e-mail:

I used to be religious, but nowadays my belief is getting weaker. For a biologist it is hard to be religious anyway...
I have bought many cheap books from the David Brown Book Company over the years and am on their mailing list. An e-mail that came today announced several books that are on sale. This was one of them:
The Instruments of Torture, Revised and Updated - by Michael Kerrigan
I am hoping it is the book that is revised and updated.

Finally, here is a photograph I took of the sculpture of Jan Karski on the campus of Georgetown University last Thursday.


19 July 2009

Ventridens suppressus on a tree


Yesterday, when I first saw this small snail (shell diameter ~5 mm) in a shallow depression on the trunk of a beech tree, I thought it was a Zonitoides arboreus. Under the magnifying glass, however, I noticed that its domed spire was more like that of Ventridens suppressus, another common land snail in the area.

At home, under the microscope, I could see the teeth inside the aperture, especially, the long outer-basal one (yellow arrow), which confirmed the identification as Ventridens suppressus.


The red arrow in the right-hand picture is pointing at the columellar tooth. In Pilsbry's (1946) terminology, this particular individual is in the 3rd or final neanic stage. During the maturation of the snail, the outer-basal tooth is resorbed; the adult snails retain only the columellar.

In most other snail species, the apertural teeth and laminae, when they are present, begin to develop as a snail approaches maturity. Ventridens suppressus is backwards in that respect; the earliest juvenile stages have even more teeth, up to 5, in their apertures. Their function is unknown.

17 July 2009

An improbable poison ivy

Lately I have been making frequent trips to Georgetown University Hospital in Washington, D.C. due to my wife's illness (details some other time). While walking along a wall at a busy section of the hospital yesterday, I noticed a lone plant growing out of a crack at the base of a brick wall.


It was a young poison ivy.


I have been noticing more and more poison ivy plants around this summer. Either I have become more aware of them or they are turning into a more aggressive plant and spreading themselves better. Could the climate change have something to do with that?

16 July 2009

Escher at the used bookstore

During yet another excursion to the used bookstore a couple of weeks ago, I found a near perfect copy of M. C. Escher, His Life and Complete Graphic Work. The price of $12 for an oversized 350-page book was one of those rare bargains.


At the cash register, the proprietor was almost embarrassed for the price: "If it had a dustjacket, I wouldn't be selling it for this price. An art book without a dustjacket is almost valueless."

What matters for me is what's inside the covers. A dustjacket is only good for getting torn anyway.

According to the caption, this was a tin can Escher designed in 1963 for a company called Verblifa.

What is nice about this book is that besides reprints of M. C. Escher's works, it also features several essays by Escher himself, including his memoirs from a trip he took to Canada in 1960.

An old post of mine about a snail in one of Escher's prints is here.

15 July 2009

Necrophagy in the backyard: Necrophila americana feeding on a dead shrew


This luckless shrew—a product of my backyard—fell victim to a certain feline whose identity may be obvious to the regular readers of this blog. The next day, these conspicuous beetles had started eating the corpse. A search in BugGuide.net identified them as the American carrion beetle or Necrophila americana; what a wonderful name.

There were times when 2, or even 3 of the beetles, accompanied with several flies, were on the shrew.


I also noticed these quite small flies. I have no idea what they are, although their red eyes remind me of fruit flies.


The only good thing that came out of this senseless waste of life—it was quite meaningful to the cat, of course—was a chance for me to observe and photograph these beetles that I had never seen before. And luckily, even in the summer heat, the odor of dead shrews, being such small mammals—this one was only about 7 cm long—is not noticeable unless you bring your nose close to them.

14 July 2009

Archaeo+Malacology Group Newsletter No. 15

The AMG Newsletter No. 15 is available here.

This issue contains articles on the mollusks found in excavations in the Middle East, the clausiliid Papillifera bidens (=Papillifera papillaris) in North Africa (seems like there is something about that snail in every issue of the Newsletter), an essay on the difficulties of distinguishing between mollusk shells modified by accidental or taphonomic processes and those intentionally modified by humans. There are also abstracts of recent relevant papers and books.

13 July 2009

Stuck between leftists and libertarians

According to the World's Smallest Political Quiz, I am a centrist, right at the corner.


Darwin was a malacologist!

Although I don’t work with freshwater snails and don’t know much about them, I happen to belong to the mailing list of a group of researchers interested in freshwater gastropods of North American (FWGNA) run by Rob Dillon of the College of Charleston. At irregular intervals, Rob e-mails to the group members his always informative and entertaining essays on various aspects of the taxonomy, ecology and biology of North American freshwater gastropods (archive). His essay of 25 February 2009 was about Charles Darwin’s interest in freshwater mollusks. Upon reading Rob’s piece, I remembered this post of mine from 2005 about Darwin’s experiments with land snails when he was trying to understand their dispersal mechanisms.

A few days later, I conceived the idea of combining Rob’s essay with my blog post in one article about Darwin’s work with mollusks in general. Rob liked the idea and I started working on it. I finished the first draft towards the end of March and sent it to Rob. He made some revisions and sent it back to me; I made a few more revisions and then sent the manuscript to Mollusc World, the magazine of the Conchological Society of Great Britain and Ireland.

Our joint effort, titled Charles Darwin the malacologist, recently got published in the July issue of Mollusc World. You may download a pdf version of the paper from here.

Darwin was truly a versatile biologist. The scope of his interests and the depths of his knowledge relative to what was known during his time are amazing.

12 July 2009

What to do with missionaries

Red Meat by Max Cannon

But do give them each a glass of wine.

10 July 2009

Smile, you are on trike-cam!

I had been meaning to attach my old camera to the front of my Greenspeed Anura to take pictures while riding. This afternoon I finally had a chance to do it. Because the camera's remote receiver is in the front, I had to turn the camera towards the back or at least sideways to be able to operate it with the remote from where I was sitting. Here is the camera attached to the front of the trike.


The exposure was set at auto, which often selected otherwise unacceptably slow shutter speeds, resulting in blurry pictures with double images, especially when I was going fast on bumpy paths. Here is shaky self portrait.


But when I was travelling slow on smooth roads, the results were better.


Here is a picture of the trike with the camera.


I have uploaded more pictures on facebook.

09 July 2009

Where do dead birds go? — Part 16

Sometimes they just stay there, like this dead catbird I photographed the other day by the side of a road. It was probably a hit-and-run victim.


Or, like these remnants of undoubtedly what was once a bird. I've been passing by them on a path on my way to and from the train station every work day for about a month.


For whatever reason, there seems to be quite a bit of interest out there in figuring out what happens to birds after they die. A Google search using the phrase "where do dead birds go" returned 11,200 hits*. I have already provided an answer in this post.

The moral of today's post is that anyone who spends a lot of time walking, while paying attention to what's on the ground, is bound to see plenty of dead birds, in addition to other types of expired creatures, for example, salamanders.

*In comparison, when I searched for "where do dead rats go", I got only one hit. I don't know if there are more rats or birds, but birds, being more visible than rats, obviously create more interest.

08 July 2009

Another well hidden tree frog


This is a gray treefrog. But is it Hyla versicolor or H. chrysoscelis? Apparently, the 2 species can be distinguished only from their calls. I need to get a sound recording device and then go out there one night to record their calls.

I photographed this individual in the park near my house. The previous well hidden treefrog from the same location was the subject of this post.

07 July 2009

That's my speeding car, all right


I got photographed doing 38 mph in a 25 mph zone in DC and had to pay a $50 fine. I had a right to request a hearing and then go to court, but do I really want to waste my time with all of that? And what was I going to tell the judge? The 25 mph limit is too low for that road, your honor. I am sure you realize that this is just a gimmick for the DC Government to take more money from the citizens. So why don't you give me a break?

Would he/she have felt sorry and waived the fine?

06 July 2009

Hermaphrodite parent and child reunion


Both of these slugs, Megapallifera mutabilis, were from the same tree. So it is likely that the larger slug is the mother or father of the juvenile.

In the wild and in captivity, this species enters pools of water to regain water lost during its daily feeding excursions on tree trunks.

04 July 2009

It was 5 years ago today

Time flies when you are procrastinating. I mentioned in this post back in December of last year that I was working on the material collected during a land snail survey we had done in Turkey early in the summer of 2004. I am still not finished, because after December I took a long break and worked on other stuff. I am now back at it and I intend to finish sorting all the specimens by the end of the year.

Imagine my pleasant surprise today when a bag of shells I picked randomly had the date of 4 July 2004. It seems like it was only, well, 5 years ago.


D51 was a pretty rich station with about 22 species. In the picture you can see a couple of long and narrow Bulgarica shells near the center and a couple of white Albinaria puella to the right. The tall white shells near the top are Zebrina cosensis, while the large, flat ones are Oxychilus samius. The tubes are holding the smaller shells.

One interesting non-snail specimen that was in the bag was this insect larva.


It appears to be a drilid larva (becaue it is hairy). The larvae of the beetles in the family Drilidae are predators of land snails. Surprisingly, I don't seem to have written about drilids before. But there is a summary of a paper I once wrote about them on this page. It was one of the first 2 papers I wrote on snails. One of these days I am going to scan it and turn it into pdf.

03 July 2009

A belated celebration of the Evolution Day

This year is the 151st anniversary of the historic session of the the Linnean Society in London on 1 July 1858 when Charles Darwin’s and Alfred Russel Wallace’s independently developed ideas on evolution by natural selection were made public for the first time.

Darwin had been developing his ideas for 20 years, but before that day he had revealed them only to a few close friends and correspondents, including the American botanist Asa Gray. Wallace, on the other hand, had come up with his version of natural selection, very much similar to that of Darwin's, several months earlier while doing fieldwork in the Malay Archipelago and communicated it to Darwin in a now famous letter*.

The presentation at the Linnean Society was initiated with a letter of introduction by Darwin’s close friends Charles Lyell and Joseph D. Hooker, opening with the words:

My Dear Sir, -- The accompanying papers, which we have the honour of communicating to the Linnean Society, and which all relate to the same subject, viz. the Laws which affect the Production of Varieties, Races, and Species, contain the results of the investigations of two indefatigable naturalists, Mr. Charles Darwin and Mr. Alfred Wallace.
This was followed by the reading of extracts from an unpublished essay Darwin had written in 1844, part of his 1857 letter explaining his ideas to Gray and the manuscript Wallace had sent to Darwin.

Why not celebrate this great idea today and everyday? Read a book on evolution, teach someone about evolution, visit a natural history museum or take a hike in the woods or go to a sea shore to witness the products of evolution. And don’t forget to remember Darwin and Wallace, for, after all these years, their idea remains indefatigable.

Hooray to the bearded guys! Pictures of Darwin (left) and Wallace are from the Linnean Society.

*According to the Darwin Correspondence Project, Wallace's letter and unpublished manuscript are missing.

02 July 2009

Helix aspersa from San Diego

A friend at work walked into my office today with a plastic water bottle containing a live snail. It was a gift* for me picked up by her husband yesterday in San Diego, California.


I am tentatively identifying it as Helix aspersa (Cantareus aspersus), an introduction from Europe. It was found with several others in a flower bed at a hotel, an unlikely place to find native local species. It is a juvenile with a soft, still not-reflected lip. First, I though it was a Helix aperta, a species I am not familiar with, but now I am leaning towards the former.

The snail still hasn't fully come out of its shell. It appears moribund, actually. Could it be suffering from jet lag? I hope it will recover and grow to become an adult so that I can be certain of its identity.

*It was the same couple who brought back Littorina littorea for me from Bar Harbor, Maine.

01 July 2009

Purple poop


This purple stain surrounding what appears to be a deposit of bird ordure was on my deck yesterday.

What had this bird eaten?


My botanical knowledge, especially when it comes to identifying plants from their seeds, is pitifully poor. Any ideas?