Phenology: Desmia: Do Moths Read This Web Site?

LOL. So far as I know, no insect reads English...though they're so alien to us that, if they did, we wouldn't know.

Yesterday on Twitter @zachdufran posted pictures of moths he'd seen recently in Oklahoma. One of them was in the genus Desmia, a group of very similar-looking species of small moths that naturally eat wild grape leaves. They have English names like "Grape Leaf Roller" and "Grape Leaf Folder." They can eat domesticated grape leaves too, so vineyard owners consider them a nuisance. Orchard owners consider wild grape vines a nuisance and appreciate these little animals' efforts to slow them down!

Photograph of Desmia funeralis shared by Greg Hume (Greg5030) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16984517 

Adult Desmias are somewhat distinguishable by size and spot patterns, but individuals can overlap species descriptions, so species are hard to identify. Even the caterpillars of the different species look somewhat alike to human eyes. The moths are among the many moth and butterfly species that slurp up mineral-rich liquids and can be persuaded to perch on a human arm, licking off traces of sweat, in hot weather. (They don't "bite"; they tickle.) Most active around sundown, they may also fly either during the day or during the night. 

Wikipedia has pages for dozens of different species of Desmia--apparently they're global--but virtually no information about them. What I know about this genus comes from this bookbook:

Bigger moths get more attention, thus more ink and photos. Smaller moths get a paragraph or two apiece toward the end.

I tweeted: 

"

I love those little Desmias...saw only 1-2 this spring; usually dozens. Glad to see that some people still have moths!

"

Between last winter's Big Freeze, some chemical contamination this spring, and admitted efforts to propagate various moth diseases to slow the westward spread of the detested Gypsy Moth, it's been a very bad year for moth and butterfly watching in southwestern Virginia. I've not seen several species that used to be common, this year, at all. Not a single stingingworm--that's good news. Not a single Walnut Sphinx or Tulip Tree Beauty--that's bad news. 

Tulip Tree Beauty photograph shared By Cyndy Sims Parr - mothUploaded by berichard, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=6624795. In real life each of those four wings covers more space than the entire Desmia funeralis shown above. Individuals inherit different color patterns that can be classified as sub-species; no two are alike. To a colorist each one is an interesting study in neutral colors.

And if I'd seen the wretched hibiscus moth, I wouldn't have been spending recent evenings picking hibiscus caterpillars off the Rose of Sharon bushes. (I first noticed these pests last summer, when they completely defoliated one bush: https://priscillaking.blogspot.com/2017/07/phenology-caterpillars-attack-rose-of.html . I suspect they've been here, overpopulating on their limited food supply, for years.) Always and forever, when whole groups of species are affected by the same factors, the nuisance species rebound first! That is how they become nuisance species--they're hardy, and both adapt and multiply much faster than the species nature intended to keep them in check.

Somehow it seems like adding insult to injury that the parents of the caterpillars bent on destroying Mother's flowers had probably been stuffing themselves silly on her blueberries. Adult hibiscus moths' favorite food is berry juice, and this was a bountiful year for berries.

Anyway, I moved on to more productive cyberchores. Then I went home. Around sundown it started to rain, and all three of the moths that were flying around the light from the window tried to crawl inside for shelter. I was typing on a laptop computer (the one regular readers remember as the Sickly Snail, named for its best operating speed), and the little Desmia moth slipped in through the window screen and perched on the computer screen.

I would not have made this up.

If the cell phone snapped decent pictures of small backlighted things, I could have snapped a picture of Desmia saying "Hello! Here I am! Write about me! Maybe some beautiful young thing will find me on a moth dating site!" 

Seriously, although most moths other than the big silk moths do eat (liquids they slurp up through their hair-sized-or-thinner, tube-shaped tongues), and have severely limited abilities to detect and evade predators, their main interest in life seems to be socializing with other moths. They fly about scent-tagging things so other moths can find or avoid them. Nature has kept the big silk moths from becoming major pests by making it difficult for them to mature and mate. Most other moths have no trouble finding mates, most years, but this year it's possible that this moth was lonely.

They're just one of many harmless, cute little woodland creatures that people kill when they spray poisons in the hope of "controlling" a nuisance species.

I know I keep banging on about this, but, Gentle Readers, if you need to "control" a nuisance species--even dreaded gyps--the way to do that is to accept that humans are predators, without becoming a poisoner. Stalk and kill your prey by all means...one, by one, by boring little one, unless (like gypsy moths) they lay eggs in clumps that can be picked and burned all at once...but don't kill creatures that never have done, or will do, any harm to you.