Author Archives: Colin Purrington

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Pyractomena borealis

Pyractomena borealis (Lampyridae) exploring the surface of trees on a warm winter day in February. The third photograph shows how they can retract their head under the carapace like a turtle. At first I thought they might be foraging — they are highly predaceous, and hunt slugs and earthworms (in packs!) by first injecting them with paralytics. But they might have just been looking for a place to pupate, because it’s time for that. Adults will emerge sometime in early Spring to be the first fireflies in the area. The larvae are bioluminescent, too. The hypothesis about why the larvae glow is that it evolved first as an aposematic trait in larvae, warning mice and toads of the presence of lucibufagins, steroidal toxins in the hemolymph. It’s thought that the adult habit of using flashes is secondarily evolved, millions of years after the larvae evolved the ability to glow. The ability of larvae to glow even predates the origin of the Lampyridae, I gather. For more enlightening details, see Branham and Wezel (2003)Stanger-Hall et al. (2007), and Martin et al. 2017.

Colin Purrington Photography: Insects &emdash; Pyractomena larva

Colin Purrington Photography: Insects &emdash; Pyractomena larva

Colin Purrington Photography: Insects &emdash; Pyractomena larva

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Rhizomorphs of honey mushroom (Armillaria)

Some photographs of Armillaria (honey mushroom) underneath the bark of a dead tree. The rhizomorphs look like plant roots but they are filled with hyphae, which sometimes emerge in a more classical mycelial fan. If you find these in your backyard, look for bioluminescence on a cloudy, moonless night. Just give your eyes about 20 minutes to acclimate.

 Colin Purrington Photography: Fungi &emdash; Honey mushroom (Armillaria sp.) rhizomorphs

 Colin Purrington Photography: Fungi &emdash; Honey mushroom (Armillaria sp.) rhizomorphs

Colin Purrington Photography: Fungi &emdash; Honey mushroom (Armillaria sp.) rhizomorphs

Colin Purrington Photography: Fungi &emdash; Honey mushroom (Armillaria sp.) rhizomorphs

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Etymology of garter snake

Colin Purrington Photography: Reptiles &emdash; Eastern garter snake (Thamnophis sirtalis sirtalis)Even though “garter snake” has been the common name for Thamnophis sirtalis for over 200 years, I discovered this week that people who know a lot about garter snakes don’t agree on why. There are two theories: (1) the snakes were named after stocking garters and (2) sirtalis is the Latin word for stocking garters and thus the common name was derived from the Latin binomial. I know, not a burning question for most, but I was curious given that snake fans seem to choose one or the other without further mentioning why. So I looked into it. 

Garter holding up a woman's stocking (from The Practical Costumer)
Photograph of an embroidered garter. Image from the The Pragmatic Costumer (click image to read her article).

(1) Most articles, books, and websites explaining the common name suggest it’s because the snakes resemble garters, pieces of fabric that were fastened right below one’s knee (the garet, in Celtic) to keep stockings from falling down (that used to be a huge problem). The resemblance is lost on most people today, especially guys who don’t know their lingerie history, because garters are now frilly and made of silk or satin and thus not at all snake-like. But back in early Europe they often had lines and patterns that could easily remind somebody of the stripes and scales of a snake. And everyone wore them: women, men, even kings, so they were ubiquitous, visible, and probably conversation starters. So it’s not surprising that somebody eventually referred to a particular type of snake as a “garter” snake. 

In etymology it’s important to establish when a particular word first appears, so I consulted the Online Etymology Dictionary and learned that garter snake first shows up in 1775, in the United States. The Online Etymology Dictionary says the name is related to stocking garter but doesn’t provide proof of this or any links. Curious, I found that “garter snake” shows up even earlier, in 1773, in a description of specimens in somebody’s collection in Lichfield, England. Again, there is no explanation of why the common name was garter. I’m sure the first usage of “garter snake” goes back even further, too, if you had access to a good database of letters and newspaper articles from the time. I don’t.

(2) A potentially related hypothesis for the common name is that sirtalis means “like a garter”. This is exactly the claim thousands scientists and naturalists make. If true, then the common name might have been launched when Linnaeus published his classification in 1758. Alternatively, maybe it just confirms that he knew of the common name and simply applied the Latin cognate for the species. But I was suspicious of this claim because when Latin was a living language there weren’t stockings or the need for garters. Sure enough, when you look up sirtalis in a Latin dictionary, it’s not there. Like many of words Linnaeus used in his binomials, he made it up by combining Latin and Greek roots, leaving us to guess at what the new word might mean. Kraig Adler theorizes that the word might be a combination of siro (Greek for cord, rope, or string) and talis (Latin for such, the like), and thus might mean “ropelike”. So when people claim that sirtalis means “like a garter”, they are incorrect. The first appearance of the “like a garter” claim seems to in 1976, in Robert Parker Hodge’s Amphibians and reptiles in Alaska, the Yukon, and Northwest Territories. I don’t own the book so I’m not sure if he cites somebody, in turn.

Although sirtalis does not mean “like a garter”, I guess it’s possible that Linnaeus had garters in mind when he concocted a rope-like species name for the snake. He probably wore garters, and perhaps called these snakes “garter snakes” before he officially named them. The question, then, is whether the common name predates his scientific name. In looking into this I discovered a second common name that I think was borrowed from German or Dutch: kouse band. The French use serpent jarretier (jarretier means garter), and Swedes use strumpebandssnok. Anyway, it seems that everyone in 1790s Europe, regardless of language, called them snakes-that-look-like-garters. Would be nice to know which language first started to call them by the respective name, but to do that I think I’d need something other than Google’s English-based book search. Note that the 1773 date I mentioned above was found with Google, and thus is probably simply related to my usage of the English-language version. There are likely other databases out there without such language problems.

A deservedly rare explanation for how the garter snake got its name is that it is a misspelling of guarder snake, garden snake, gardener snake, or garten snake. Some of these variants are quite common on the internet, and I think most people can blame their parents. 

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Green slime mold

Plasmodial slime molds (class Myxogastria) come in many colors (yellow, purple, orange, blue, red), but rarely in green, so this find at a local park intrigued me. I found it February 23 under the bark of a decaying pine tree in Springfield, Pennsylvania. There were no fruiting bodies. 

I’m curious what species it is (let me know, if you know, please), but would love to know why it’s green. Here are three possibilities (I have more, if they fail): (1) the slime mold has formed an association with an algae or cyanobacteria, (2) the green pigment replaces the yellow pigment under some conditions, and (3) this is a species of slime mold that’s green but not frequently encountered so not part of books and online keys. The latter two are most likely, but the first was interesting to consider … see below if you have a few minutes.

Colin Purrington Photography: Slime molds &emdash; Green slime mold

(1) In regards to algal associations, I looked into this option first because the green appeared so exactly like that of alga. Of course, I’d never, ever heard of algal/myxomycetes symbiosis, so I looked into this possibility very, very quietly so people wouldn’t spew coffee out their noses. But I eventually found an article on the topic (Lazo, W. 1961.Growth of green algae with Myxomycete plasmodia. American Midland Naturalist 65:381-383). Here’s the summary from his abstract:

“Three species of Chlorella were able to enter into full associations with Physarum didermoides and Fuligo cinerea, forming green plasmodia in which the algae multiplied in light.”

The above association was under special laboratory circumstances, however, notably using slime molds that he’d purged of their bacterial partners with antibacterials. But even though the conditions might seem artificial, I suspect slime molds have a built-in ability to purge themselves (and surrounding substrate) of bacteria. And algae are easily found growing in soil and on dead trees, so it’s very likely that slime molds and algae come into contact in the wild regularly. And algae (or at least some species like Chlorella) can grow heterotrophically in the dark (e.g., on sucrose) and still remain green. This latter fact is important because I found this slime mold under rather thick bark, and I doubt it received any appreciable light. 

Indeed, some plasmodial slime molds appear to even specialize on the algal biofilms growing on wood (reviewed in Smith 2007). One mentioned by Smith is Barbeyella minutissima, which I Googled and found this:

“In addition to liverworts, Barbeyella is found socialised with monocellular algae. It is assumed that the protoplasmodium phagocytizes either the algae or the bacteria on their surface.”  — Global Fungal Red List Initiative

Smith also mentions that a Didymium iridis plasmodium harbored an alga (Trebouxia sp.) for months in a laboratory culture (Keller and Braun 1999; I couldn’t obtain to read).

So if the above scenario does occur, perhaps it’s similar to the trick noticed in some Dictyostelium spp. (cellular slime molds, in the class Dictyostelia), which known to carry around bacteria, which they can release onto substrates that are favorable for bacteria (i.e., they farm). 

Anyway, I don’t have a microscope to examine the slime mold for algae or cyanobacteria, so the above is just mere speculation. I suppose I could spray it with a good herbicide, but that’s seems cruel.

(2) The green color might simply be a pigment change. I don’t know much about myxogastrid pigments, but apparently moisture, light, starvation and other environmental factors all cause color changes. But I could find only a few papers discussing a green pigment. Here’s the best line from one of them:

“The yellow pigment of P. polycephalum has been found to be an excellent natural pH indicator (Seifriz & Zetzmann, 1935). In a neutral medium, the natural indicator is yellow, in an alkaline medium it is bright green, and in an acid medium it is deep reddish orange.” Seifriz and Russell (1936) [emphasis added]

[The citation of the referenced paper, which I couldn’t obtain in full, is Seifriz, W., and M. Zetsmann. 1935. A slime mould pigment as indicator of acidity. Protoplasma 23:175-179.]

The above fact is really interesting, but don’t know why a decaying pine log would become alkaline. I couldn’t find any good research on the topic, but perhaps I missed it.

The more interesting scenario is that a pigment gene is mutated. Mutations happen, though it’s rare enough that I don’t think it’s likely. 

(3) It’s of course most likely that there’s a species of green slime mold and I’m simply ignorant of its existence. Maybe it’s not even a slime mold.

(4) Or it could be oobleck


Some more pics:

Colin Purrington Photography: Slime molds &emdash; Green slime mold plasmodia

Colin Purrington Photography: Slime molds &emdash; Green slime mold

 

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Snow midge with yellow halteres

Here’s a snow midge I found a few days ago at Hildacy Farm Preserve. I’m not positive about the species, but perhaps Diamesa nivoriunda. I only saw one, but related members of the genus are reported to swarm during the winter. 

What I’d love to know is why the halteres are yellow. They seem to be yellow on majority of diptera I’ve seen, and I’ve never stumbled onto a paper discussing why that is. All I could find was the sentence “Haltere color is often used to distinguish between species” in a Drosophila book .” If you know of a paper, please send link ASAP. Am dying of curiosity.

 Colin Purrington Photography: Insects &emdash; Snow midge (Diamesa nivoriunda)

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