Another Viral Moth Video....

In service to my colleagues who have waning patience as they are bombarded with the latest social media sensation, I offer this explanation to the moth with the "tentacles" coming out of its posterior. Here is the circulating image, but there is also a video that is associated with most Facebook posts.

© "Gandik" via Facebook

Ok, first things first. This moth is Creatonotos gangis, an arctiine (tiger) moth from southeast Asia and Australia. The specimen shown is a male. He is everting his androconial glands or coremata (Greek for "feather duster"). The glands are normally concealed within his body, and are inflated at will by air pressure or blood pressure. Less dramatic versions of these organs are known as "hair pencils." Usually concealed within his abdomen, the coremata are deployed when he is seeking acceptance by a mate.

Male pyralid moth deploying his "hair pencils" © Nicky Bay

Wait, you thought female insects were the ones using pheromones (scents used mostly to attract the opposite gender, but with other functions, too, especially in social insects)? Well, me, too, so I did a little digging. Turns out that the male's sexual chemicals are not meant for long-distance attraction of females, but to communicate his "fitness" as a mate. So, the products of androconial glands have been likened to aphrodisiacs, tranquilizers, or narcotics, aimed at seducing the female. Ok, but how? It is a long story....

© David Rentz via Joanie Mars on Facebook

As caterpillars, many tiger moths (subfamily Arctiinae of the owlet moth family Erebidae) feed on toxic plants. Milkweed is a good example. The plant is packed full of cardiac glycosides, potent poisons intended to discourage herbivores, including caterpillars, from consuming it. Not only are some caterpillars able to overcome the toxicity, they incorporate it into their own bodies to make themselves toxic to their predators. This is called sequestering, and the commandeered poison stays with the insect throughout metamorphosis and into adulthood. One of the byproducts in male moths is the pheromone emanating from those androconial glands. He thus demonstrates to the female that he is genetically superior based on a greater quantity of accumulated toxins that she can then pass on to her offspring.

Our common U.S. Acrea Moth everting his glands © Rosella Flores

This is a relatively dry explanation of these remarkable structures in male tiger moths. You owe it to yourself to be better entertained and further enlightened by an article in Wired magazine by my good friend and colleague Gwen Pearson. Even the graphics are better, and a GIF has never been funnier, at least in the context of entomology.

Close-up of male Acrea Moth glands © openi.nlm.nih.gov

So, far from "terrifying" as a similar viral graphic was labeled in a headline from Huffpost, these glands are an amazing example of evolution, just like elk antlers and other male adornments. Please share the fascination, without the sensationalism. Thank you.

Hatched!

Remember the “Carpet Cocoon” story I did back in March, and the one on the “Carpet Caterpillar,” too? Well, the story has come full circle now.

Sometime last night, an adult moth emerged from the pupa that the caterpillar formed in the yogurt cup I had it in. I remember thinking that I needed to put a paper towel or tissue around the inside of the smooth cup so the moth could climb up and fully expand its wings for a successful molt. Naturally, I had the lid off the cup, covering a small, live beetle on my drafting table last night….So, this is what I found this morning:

An empty cup, with a now empty pupal case (and caterpillar head capsule at the left). No moth to be seen anywhere. Terrific. I looked high and low, and finally, by sheer luck, discovered the surprisingly large, perfectly healthy moth tucked neatly in the door jamb of the front door, at about ankle level. It had managed to eclose (the scientific term for emerging as an adult insect from a pupa) perfectly, in the most imperfect circumstance, with no further intervention from me. Astounding.

The comments I received on my initial post about the caterpillar were mostly directed to my assertion that the moth was nothing much to behold. I only had images from BugGuide.net to go by, and I was not impressed. Suffice it to say that seeing the living creature has changed my opinion. It seems to have actually transformed the carpet fibers into the shimmering scales on its wings.

I had errands to run today and was in and out of my apartment frequently. On the last, late afternoon return home, the moth flew out the door. Ah, freedom! Well-deserved, too, I might add.

Carpet Cocoon

One day after I discovered the ”Carpet Caterpillar,” I discovered the remains of its cocoon in my living room carpet. This also explains why the caterpillar was so lethargic when I found it: a great amount of energy is expended in preparing to pupate.

Actually, there were the remains of two cocoons. Since I did not find another caterpillar, I suspect that I disrupted the one animal on two occasions. I was using boxes that had been in that spot for ages, and the caterpillar, once exposed, probably sought refuge under another box that I also eventually used.

You can even see the “trail” between the two pupal cells, a tiny trough in the carpet. Whether this represents actual damage to the fibers I have yet to find out (hey, I’m blogging, not vacuuming).

Carpet Caterpillar

At this time of year, even here in southern Arizona, I am always a bit surprised to find insect activity. Imagine my shock then at finding a caterpillar on my living room floor today. It was a familiar species, but still a bit early I think.

Tucson is landscaped with a plethora of ornamental fan palms, and it is from these trees that my caterpillar came. Known as the “palm flower moth” or “palm budworm,” depending on its life stage, Litoprosopus coachella is a frequent home invader in urban areas.

The mature caterpillars (roughly 25 millimeters in length) crawl off the tree to find a suitable place to spin a cocoon, and this sometimes takes them indoors. High winds will also dislodge them by peeling bracts off the trunk of the tree and sending them flying across the yard and against buildings. Any attached caterpillars will fly away with those botanical missles.

Despite their abundance, and appetite for the blooms of their host plant, the caterpillars are generally considered more of a nuisance than a bona fide pest. They may do minor damage to carpets once they get indoors and chew off fibers to incorporate into their silken cocoon.

The caterpillars are not terribly attractive, being a dusty greenish or pinkish color, devoid of much hair, and can be mistaken for a beetle grub at first glance. Look at the head. The two tiny spots near the corner of its mouth are one set of eyes. Most caterpillars are nearly blind, though, relying on tactile and chemical cues to navigate their world.

The remainder of the head capsule, that round, hardened area at the front, is filled mostly with muscles to operate the jaws. What jaws they are, too! The first time I found one of these, I made the mistake of trying to simply pick it up. I got a nasty nip out of it, and my reflexes sent the poor creature flying across the room. Ouch! Gila woodpeckers and northern mockingbirds are not as easily dissuaded as I, and feed heavily on these larvae.

Unfortunately, this insect does not redeem its appearance much through metamorphosis. The adult moth is equally dull and drab. Well, I suppose beggars (for signs of spring and the company of other animals) can’t be choosers, at least not in February.