28 April 2010

Blogging will be interrupted

My wife has been undergoing treatment for cancer since last summer. Unfortunately, her disease has progressed. In the beginning of April, she was moved from the hospital to the hospice with the giant clam in its garden. As she nears the end of her journey, I have no choice but to suspend blogging for several days.

My life is at a juncture; it's been changing and will continue to change until I settle down on a new path, which, if I look wisely, may be found just around the corner. This little poem is from Zen Flesh, Zen Bones.
It is too clear and so it is hard to see.
A dunce once searched for a fire with a lighted lantern.
Had he known what fire was,
He could have cooked his rice much sooner.
I intend to resume blogging sooner than my rice is done, perhaps within a few days. But I must go now.

26 April 2010

Conopholis americana at noon

During yesterday's slug hunt, I kept noticing these peculiar things poking out of the leaf litter everywhere in the forest. I couldn't tell if they were some sort of fungus or an unusual plant. So I e-mailed their picture to Butch Norden of the Maryland DNR, my usual expert on all things wild.

Sure enough, Butch identified the organism as Conopholis americana, a non-photosynthesizing plant commonly called squaw root that is parasitic on the roots of trees, especially oaks and beech. It is native to eastern North America. The only above-ground parts of the plant are the flowers in the picture. I don't know if and what insects pollinate them.

An unusual plant indeed.

25 April 2010

A good day as far as slugs are concerned

Last night's rain and this morning's warm and cloudy weather had brought the local Megapallifera mutabilis out. Within about an hour around noon today I found and weighed 10 of them. That's 10 more data points for our ongoing project to deduce the population cycle of this species by monitoring their sizes during a year.

Today's surprise find was this big daddy-o. It wasn't even fully stretched when I took this photo.

It weighed 5.75 grams; definitely one of the heaviest Megapallifera mutabilis I have so far weighed.

There may be updates.

24 April 2010

A tree for woodpeckers

I photographed this pockmarked dead tree in the park near my house a couple of weeks ago. The numerous holes decorating its trunk are undoubtedly the creations of woodpeckers.

A cluster of holes were only a meter or so above the ground. I've never seen a woodpecker pecking on a tree that close to the ground. But, perhaps they do that when they know there is no nearby predator.

22 April 2010

World's smallest T. rex is a snail!

Carl C. Christensen, our correspondent in Honolulu, e-mailed this item of utmost importance yesterday:

A recent news item claims that a South American leach, Tyrannobdella rex, is the world's smallest "T. rex," with a body length of less than two inches*. In the interest of defending the honor of the Mollusca, it should be pointed out that Cowie, Evenhuis, & Christensen's 1995 "Catalog of the Native Land and Freshwater Molluscs of the Hawaiian Islands" includes on p. 118 an entry for Tropidoptera rex (Sykes, 1904), a species of the pulmonate family Amastridae endemic to the island of Oahu, Hawaii. Hyatt & Pilsbry (1911), on p. 126-127 of vol. 21 of the second series of the Manual of Conchology, give the maximum dimension of the shell of Pterodiscus rex Sykes, 1904, as 14.5 mm. As Pterodiscus Pilsbry, 1893, is now regarded as a synonym of Tropidoptera Ancey, 1889, it appears that the Hawaiian Islands have defeated South America for the honor of being home to the world's smallest T. rex. Snails RULE!

The shell of the snail Tropidoptera rex, the world's smallest "T. rex". Drawing from the Manual of Conchology, vol. 21, plate 24.

*The original description gives the preserved body length of the holotype as 44.5 mm. See: Phillips et al. 2010. Tyrannobdella rex N. Gen. N. Sp. and the Evolutionary Origins of Mucosal Leech Infestations". PLoS ONE 5(4): e10057.

21 April 2010

Why are there no single-celled terrestrial organisms? Part 2

In response to the Part 1 of this series, our friend and regular reader Carl Christensen e-mailed an article all the way from Hawaii early this morning. The article1 has in its title the words "free-living terrestrial microorganisms" and is about the human-mediated dispersal of testate amoebae that live in the soil. While reading it I was reminded of a much older paper2 in my collection with the intriguing title "Colpoda cucullus: a terrestrial aquatic". That paper is about the ciliate C. cucullus, which also lives in the soil as well as on various plants.

Despite the authors' use of the qualifier terrestrial in referring to their subject protists, the latter are not terrestrial in the sense I was discussing in this post. They may live in soil or on the surfaces of plants, but they are active only when fully immersed in water. They are obligately aquatic. They may be called "terrestrial aquatic" only because their watery habitats in the terra firma are often too small in volume to be noticeable by humans.

To be continued.

1David M. Wilkinson. 2010. Have we underestimated the importance of humans in the biogeography of free-living terrestrial microorganisms? Journal of Biogeography 37:393–397.
2Mueller & Mueller. 1970. Colpoda cucullus: a terrestrial aquatic. American Midland Naturalist 84:1-12.

20 April 2010

A book for the snails and slugs of Canada

Those who are interested in the terrestrial gastropods of Canada now have a book at their disposal: Identifying Land Snails and Slugs in Canada – Introduced Species and Native Genera. This recently released work is a joint effort by F. Wayne Grimm (deceased), Robert G. Forsyth, Frederick W. Schueler and Aleta Karstad. Free copies may be ordered from the Canadian Food Inspection Agency.

The 166-page paperback book includes the descriptions of all the native and the introduced terrestrial gastropod genera of Canada as well as the descriptions of all the introduced species. Good photographs or drawings of all of the introduced species and many of the natives are also provided. Aleta Karstad's watercolor drawings of the introduced slugs are especially noteworthy. Many of them can easily pass for photographs.

The book opens with several sections giving general information on terrestrial gastropod biology and collecting and studying techniques that would be useful for newcomers and closes with an illustrated glossary and a list of references.

My criticisms are minor and stem from my personal biases and needs. I dislike the silly common names for gastropods that have been circulating out there and would rather have nothing to do with them. But unfortunately they were used in this book. I also wish more detailed locality information for some of the introduced species had been given. For example, the coordinates of the only location in Canada where Succinella oblonga has been found would be of more help than the unelaborated "along Hwy 12 north of Brooklin, Durham Regional Municipality, Ontario". The latter is reminiscent of the locality data of Wayne Grimm from the 1950s when nothing better was expected.

I congratulate the authors for this otherwise well-prepared and quite useful book. It will undoubtedly be the standard reference for the Canadian snails and slugs for many years to come. I will certainly take it with me the next time I am going to Canada.

19 April 2010

Why are there no single-celled terrestrial organisms? Part 1

In this post I discussed what its means for an animal to be terrestrial. All animals (Kingdom Animalia) are, by definition, multicellular, while the unicellular organisms belong to the Kingdom Protista. As far as I know there are no terrestrial protists.

In the present post I will give some reasons why I think there can be no terrestrial protists.

1. Unicellular protists tend to be very small for the obvious reason that they consist of but one cell. The ratio of the surface area to volume of an object increases as the object gets smaller. Therefore, a unicellular terrestrial organism would have a very large surface area to volume ratio and consequently great difficulty to prevent water loss thru its membranous boundary with the external environment. An impermeable coat could prevent water loss, but it would then be difficult for the protist to receive the required oxygen and food.

2. How would a unicellular terrestrial organism reproduce? Division or the production of any propagule would further decrease size and increase the surface area to volume ratio and the rate of water loss.

3. It would actually be quite difficult for a microscopic unicellular terrestrial organism to free itself from water droplets that it might come in contact with. Water tension would probably be an insurmountable force at such tiny dimensions.

Disclaimer: As I point out occasionally, many ideas that I post here for the whole world to read are often of the half-baked kind. The present ones may not be exceptions. If you intend to cite or steal them, do at your own risk.

Part 2

18 April 2010

What are the chances that you will be walking by a garden and there will be a giant clam there?

I chanced upon these valves of a Tridacna gigas in the garden of a local hospice I was visiting today. My initial thought was that they were perhaps concrete imitations. But a closer look revealed all the defects, the buildup and the growth rings one would expect on a real clam shell.

How often does one just find giant clam valves tucked away in the corner of a garden somewhere far away from the ocean unless one is dreaming? And I wasn't dreaming. But life is full of surprises.

16 April 2010

This morning's excitement: a snake on the road

While riding my trike up a hill in a somewhat secluded part of the town this morning, I passed by this snake sitting in the middle of the road. I quickly pulled to the side of the road, walked over to the snake took 2 pictures of it with my iPhone camera.

Under different circumstances I would have left the snake alone, but realizing that any passing car would very likely have squeezed the life out of it, I decided to relocate the reptile. Luckily, there was a long tree branch nearby. Using it, I prodded the snake's tail 2 or 3 times and each time the snake bravely struck at the stick—which was much longer than itself—with an open mouth; pictures would have been great, but an iPhone camera is not the right tool for action photography. Eventually, the snake decided wisely that it would be better off getting off the road and into the grass it went.

What species is it? The last time I identified a snake as a ribbon snake (Thamnophis sauritus), it turned out to be garter snake (Thamnophis sirtalis). So this time I am going to call it a garter snake. Correct me if I'm wrong.

15 April 2010

Just when you thought it was safe to collect shells you get eaten by the natives

This is from the August 1891 issue of The Nautilus:

I have just learned through Mr. Rossiter, of the Island of Noumea, that Mr. de Latour and his son (from whom I have received so many new shells from Aura Island, New Hebrides) have been murdered by natives; Mr. Garrett was wont to tell me of the great danger to be encountered by these collectors in these islands from the natives. When he was collecting in some of these islands he was obliged to be a walking arsenal and would never trust a native behind his back for fear of being stabbed and dragged off into the bushes and eaten.
New Hebrides was the former name of a group of islands now called Vanuatu. A Google search using the string "New Hebrides cannibalism" returned more than 38,000 hits. Most of the hits appear to be 19th century or early 20th century hearsay accounts. Here is an example from 7 October 1899 New York Times:

The 1st paragraph gives an idea how many times the "news" must have been told and retold took before it reached New York. It's amazing that "reputable" newspapers took such stories seriously. The provenance of the item from The Nautilus was equally murky: it was an excerpt from a letter sent to Henry Pilsbry (the editor) by a Dr. W.D. Hartman who had heard the murder story from a Mr. Rossiter and the perilousness of the islands from a Mr. Garrett.

This is not to say that New Hebrides was a safe place for Western shell collectors; it probably wasn't and ritualistic cannibalism may indeed have been performed by the natives. But I suspect most Western accounts of savage, rampant cannibalism in the South Pacific and elsewhere were baloney.

14 April 2010

Science concerns itself with trifles

In the introduction to The formation of vegetable mould, through the action of worms, Charles Darwin wrote:

The subject may appear an insignificant one, but we shall see that it possesses some interest; and the maxim "de minimis lex non curat*," does not apply to science.
Darwin was referring to the study of earthworms. He was, of course, correct that a real scientist can not and should not dismiss a research project, especially in natural history, because it may appear insignificant and unimportant to his restricted worldview. There is so much remains undiscovered in the life sciences that one can often not tell beforehand what unexpected results a particular research project may lead to.

I read Peter Medawar's book Advice To A Young Scientist many years ago in graduate school. If I am remembering it correctly, Medawar was of the opinion that a young scientist would be better off not wasting his time with what he thought were trifle projects. By the time I finished Medawar's book I was so annoyed with his ideas and arrogance that I threw it away.

I'd rather stick with Darwin.

*The law does not concern itself with trifles.

13 April 2010

A well hidden slug

Last Sunday morning's slug search, in addition to an incidental salamander, yielded 3 individuals of the philomycid slug Megapallifera mutabilis that I was after. Here is one of them in situ.

This slug was on damp soil under a pile of leaves among the roots of a beech tree. I removed it, cleaned off the debris that was stuck to it, weighed it and then returned it to its hideout. Its weight, along with those of the other 2 slugs, is now part of the data for an ongoing project that is trying to understand the annual generation cycle of this species.

While resting, these slugs—all slugs—try to maintain bodily contact with a wet surface whenever they can. Foraging out in the open often results in water loss via evaporation thru the skin and as slime. The drier the atmosphere and the surface a slug is on, the larger the water loss. Therefore, to regain the lost water slugs hide in wet tree holes, on damp soil under rocks or plant debris or similar spots.

These generalizations, also valid for snails, were the subject of a recent paper of mine.

12 April 2010

A well hidden salamander

I found this small salamander while looking for slugs yesterday morning. It was under a pile of leaves stuck among the roots of a beech tree. It attempted to crawl into a crevice, but I was able to retrieve it by gently pulling on its tail, which, luckily, didn't break off.

I believe it's a lead-backed morph of the eastern red-backed salamander (Plethodon cinereus). Both this morph and the red-backed morphs seem to be the most common salamanders around this parts of Maryland.

Once it was in my hand, it was very lively and kept crawling between my fingers trying to get away. Noble wrote in his book The Biology of the Amphibia that "Salamanders, frogs, and toads may be readily thrown into a state of tonic immobility which, under certain circumstances, may prove a protective measure...It is commonly seen in such salamanders as Plethodon and Ambystoma, which when handled gently often exhibit a 'death feint'".

This particular individual had obviously not read Noble's book.

11 April 2010

The beech that won't die

This mighty American beech (Fagus grandifolia) came crashing down sometime in late December 2008 or early January 2009 in the park near my house (see this post). I had originally assumed it was dead wood for good, but in July of 2009 when I saw its green leaves I realized that it was still alive (see this post).

Now more than a year after it became horizontal, the beech is still refusing to let go. I took these pictures today as I stood on it while admiring its new leaves.

But trees are supposed to grow vertically. I wonder how long our tree can carry on with its deviant existence.

09 April 2010

Getting along nicely under the rocks

Once the weather begins to get warmer and the top soil thaws, the hypolithic animals return from their undisclosed winter hideouts to the undersides of the rocks. They are still hidden most of the time, but one can now find them easily by overturning rocks. About a week ago, a couple of large rocks in the backyard, when overturned, displayed their menagerie of arthropods.

Swarms of ants and isopods, apparently tolerating each other well, were underneath both rocks. A detailed look at the clusters of ants revealed many eggs or larvae being transported.

Detailed looks at other spots under the same rocks also revealed several millipedes or millipede-like creatures among the ants and the isopods.

I hadn't noticed them while taking pictures. Obviously, the ants are leaving alone the isopods and the millipedes.

Absent were snails and slugs. Although slugs and isopods tolerate each other, I don't know if ants and gastropods are ever found together in large numbers.

08 April 2010

The pumpkin that is coming back

It turned out that the pumpkin that was refusing to go away was actually in the process of resurrecting itself. When I got curious this afternoon and lifted up the top of it, this is what I saw.

The seeds were all there. The close-up shows several of them sprouting.

So the about-to-turn-into-soil looks of the ex-pumpkin was only a front to hide the photosynthetic machinery that was being assembled underneath.

Photosynthesis cannot take place without sunlight. So I removed the top of the pumpkin and left the sprouts exposed. We will see how successful they will be in their mission to take over the backyard.

Updates may be posted.

07 April 2010

Message from the sidewalk

Can that be true?

The previous message from the sidewalk.

06 April 2010

It was a cold and foggy morning

Foggy view from the hotel window. October, 2008, Kastamonu, Turkey.

One of the cities we visited during our trip to Turkey back in October 2008 was Kastamonu. We stayed at a hotel of some sort on a hill at the outskirts of the city. When I got up on our 1st morning, the sun hadn't risen yet and a dense fog was shrouding the hill. My travel companions were still in deep sleep. I grabbed my field bag and quickly left for the hillside in search of snails.

It was cold outside and the fog had covered everything with tiny drops of water. Despite what was for me an uncomfortably low temperature, I was amazed when I saw that there were snails everywhere. I spent about an hour taking pictures and notes. For the following 2 mornings I repeated my field work. This was followed by some simple experiments with captive snails.

Zebrina detrita crawling on dew covered grass. Photographed near Kastamonu, Turkey.

The results of those studies was a neat little paper titled "Activities of four species of land snails at low temperatures" that recently got published in the Journal of Conchology. You may download a pdf version of it from here.

Incidentally, this was the manuscript that I had to revise to bring the number of words from 1287 down to 1045 to satisfy the editor. That story was here. While preparing this manuscript I also had to learn some basic meteorology. Some of that was discussed in this post.

05 April 2010

The more newspapers change the more they stay the same

My perennial annoyance with newspapers will not end until the last one shutters its doors.

The general unscientific and unintellectual attitude of the news media is, of course, nothing new. The following was published under the heading "Newspaper Conchology" in the February 1893 issue of the Nautilus.

The gloriously free daily press of this country does not often discuss scientific matters, but when it does, facts are apt to be mangled. The following clipping is not so bad : "It is generally supposed to be a sign of wet weather when snails go about without their shells. One species of snail never takes its walks abroad except when rain is at hand. Some climb trees two days before a down fall, setting upon the upper side of the leaves if a storm is to be of short duration, but taking shelter on the under side if it is to last some time. Still other snails turn yellow before rain, and blue when it is over."
This short, anonymous note without a citation was probably written by Henry Pilsbry who was the editor of the Nautilus at that time. If he could consider claims of color changing snails leaving their shells during rains "not so bad", I don't want to know any of the stuff that was bad.

02 April 2010

The pumpkin that refuses to go away

This pumpkin was picked last October. For about 2 months it sat seemingly intact on our front porch, enduring the fall rains. Sometime in December, I think, I got tired of seeing it there and brought it to the backyard. There it began to shrivel slowly. Then it was under the snow for quite sometime.

Now the cold weather is gone, but the pumpkin is still there, although it takes a little bit of imagination to recognize that it is a pumpkin.

How long will it resist the onslaught of the spring?

Note added 8 April: this post has an update.

01 April 2010

My computer is bugged!