25 July 2023

13 July 2023 – Arts and Sciences 

The trap this morning was predominantly ‘Common’, with 57 Common Rustics and 28 Common Footmans making an appearance.The Heart and Darts were as populous as usual, numbering 28 as well (although they seem to be getting significantly more worn and lethargic).The Large Yellow Underwings’ reign of terror continues. With every egg carton I removed from the trap, I became more and more certain that these lepidopteran fighter pilots enjoy flying straight into my face! They’re now appearing in droves. In the last trap, there were five, but this morning I counted 23! Their single redeeming quality, in my opinion, is their tendency to ‘stack’ in the narrow crevices under the egg cartons. Balanced one on top of the other, they look less sinister. Comic relief!

I’m usually not drawn to the smaller moths, but the Chinese Character (Cilix glaucata) is an exception. It falls into the ‘Bird Dropping’ category for its initial guano-like appearance, but upon closer look, it is rather beautiful! (I will be taking offense on behalf of the Cilix glaucata for this comparison, however evolutionarily advantageous this resemblance may be.) Its sea-shell shape and closed-wing resting position makes it the outlier in the Drepanidae (Hook-tip) family. When looking into the origin of the name Chinese Character, I was a little worried that it might be… outdated. I was glad to discover that Character is here used to mean symbol: The thin white marking on the moth’s wing is said to look like the Mandarin character 山 (shān), which means ‘mountain.’

Trying to find out which (seemingly bilingual) lepidopterist gave the Chinese Character its english name was fruitless, but I did fall down the rabbit hole of non-English common names. This moth is widely distributed throughout Europe, Asia Minor and North Africa, and has many different common names in all the languages therein! This entomology and etymology forum gave the Chinese Character moth’s name in a variety of languages:

German: Silberspanner (Silver Spinner), Weißer Glanzspinne (White Shine Spider), Schlehen-Sichelflügler (Blackthorn Crescent Wing), Eulenspinner (Owl Spinner)

Dutch: Witte Eenstaart (White Tail)

French: La Petite Épine (The Little Thorn)

Norwegian: Slåpetornsigdvinge (Sloe Thorn Sickle-wing)

Welsh: Gwyfyn Arian y Drain (Silver Thorn moth)

Finnish: Valkosiipi (White-wing)

I found all of the names to be quite endearing. And what a revelation. Most moths probably have many common names in different languages. I’ll have to explore this more in the future with other moths!

The Riband Wave deserves a feature both for its beauty and relative increase in frequency. These members of the Geometridae family usually appear in pairs or groups of three in the trap. I’ve found them to have a distinct personality. They’re less flighty than other Waves, and when they do get startled and fly away, they make a measured and graceful exit. Like peppered moths, they have a darker form and a plain form, remutata, the latter being the one we typically see at Shandy Hall. Their larval food plants include Dock (Rumex), Dandelion (Taraxacum), and other “low” plants, rendering them well fed in our garden!

Chris found this caterpillar in the Wild Garden, expertly camouflaged on the stalk of a Common Nettle (Urtica dioica). I hypothesized that it was a Burnished Brass (Diachrysia chrysitis) caterpillar because of its geometric white markings and bright lime color. Patrick pointed out that it had four pseudopodia, or ‘prolegs,’ deductively ruling out the Burnished Brass with only two pseudopodia. Patrick suggested that this caterpillar was a Spectacle (Abrostola tripartita), which, after checking with local expert Dr. Charles Fletcher, turned out to be correct! It made sense that we found it on the nettle, as that is the Spectacle’s only larval foodplant.

I was curious about pseudopodia: These appendages, often called “false legs,” are evidently common anatomical features on caterpillars and larvae of all sorts. As the name suggests, they don’t qualify as actual legs. Caterpillars do still have six legs, which aren’t used in all locomotion, but are helpful in certain activities such as climbing up leaves. Prolegs, on the other hand, are invaluable to caterpillars! To understand why, observe that caterpillars have neither an endoskeleton or an exoskeleton. Muscles (of which caterpillars have over 4,000!) work by contracting, and in order for the contractions to influence the organism’s position, they must contract against something rigid. Humans, with our endoskeletons, are able to move our bodies on land, in water, and in air because our muscles pull against our rigid bones: We don’t need a stabilizing external structure in order to move. But Caterpillars, as previously mentioned, don’t have any such rigid internal structures to pull against! That’s where the prolegs come in. Each proleg has a little hook on the end, which works by digging into a harder surface, such as a leaf or a twig. Then, the caterpillar uses that external surface as an anchor for its muscles to contract against! The hooks work by being continuously filled with, and drained of, fluid within the caterpillar’s body. When the proleg is filled, the hook pops out of the end, much like a cat flexing its paw to reveal its claws. When it’s drained, the hook retracts back into the proleg, releasing whatever the caterpillar was previously attached to.

Pretty amazing bioengineering for such tiny creatures!

Post : Autumn Cortright (UPenn intern)