This gorgeous yellow caterpillar is an American dagger moth (Acronicta americana), a 2-inch long member of the owlet family Noctuidae. As a caterpillar he attracts attention.
As a moth he does not.
The difference is a matter of self defense. The adult American dagger moth is probably good to eat so he does his best to hide.
The caterpillar is conspicuous because he has a toxin in his black bristles that cause a stinging sensation when the bristles break off and embed in skin. Like many poisonous animals he’s using aposematic coloration and behavior to simultaneously attract attention and warn off predators, “Look. Don’t eat me.” Other examples include poison frogs, monarch butterflies and skunks.
Have you seen an unusual white squiggle on a green leaf? The pattern was made by a leaf miner, a tiny insect larva that eats a path between the top and bottom surfaces of the leaf. The path ends when the larva is ready to pupate. When the insect departs it leaves a hole.
There are many tiny moths, beetles, sawflies and flies that make leaf mines. Some create blotches. Others, like this one, make serpentine paths. You can identify the insect(s) that made the paths — or at least narrow the number of species — by noting the type of mine and identifying the plant host.
The larvae of a tiny fly, Liriomyza eupatoriella. (NOTE: While researching this insect I discovered Charley Eiseman, an expert on leafminers and author of the only photo of the bug at bugguide.net. More on Charley Eiseman below.)
Coquina clams (Donax variabilis) are tiny saltwater molluscs found on sandy beaches from Virginia to Texas. Their variable colors are beautiful and at only 3/4 inch long they are just the right size for collecting. I usually find an empty half shell rather than two joined like butterfly wings (above).
Since I only pay attention to empty shells I never thought about where they live and how they get there until I saw this video. Watch two coquina clams disappear in the sand.
I find it very peaceful to watch coquina clams slipping into the sand where the ocean meets the land. Video from July 2021 near St. Augustine, Florida. pic.twitter.com/wWtp6rhxvE
Last night at sunset I heard a bug outside my window and found a scissor-grinder cicada (Neotibicen winnemanna) perched on the bricks outside the glass. He sang his courtship song to attract a mate, a repetitive WEEE ah, WEEE ah, WEEE ah, WEEE ah that tapers at end. It’s a sound so unique that he can be identified by song. Click here to hear.
When the cicada left he flew directly at my window and bounced off the glass, over and over again. I imagine his 5 eyes were fooled by a reflection of the sky.
Don’t confuse our annual cicadas with the 17-year periodical cicadas that emerged in D.C. last May and disappeared in July. Scissor-grinders emerge every year in July and peak in September and they look different from each other.
Annual cicada in Pittsburgh, probably scissor-grinder.
17-year cicadas are not in Pittsburgh this year. See the red eyes!
(photos by Kate St. John, Dana Nesiti and from Wikimedia Commons)
Moths are eaten by birds, small rodents, bats, and lizards and are especially vulnerable during the day. To avoid predation many hide in plain sight. Here are four moths that use camouflage to survive.
The peppered moth (Biston betularia) is a camouflage master. The adults look like bark, the caterpillars (above) look like twigs.
Research indicates that the caterpillars can sense the twig’s color with their skin and match their body color to the background to protect themselves from predators.
Here’s a beautiful moth we wouldn’t see if it weren’t for an invasive tree.
The ailanthus webworm moth (Atteva aurea) is a tropical ermine moth that relied on the paradise tree (Simarouba glauca) and Simarouba amara as its larval hosts. In the U.S. this limited the moth’s range to South Florida.
However in 1784 we began importing an Asian member of the Simaroubaceae family, the tree of heaven (Ailanthus altissima), because we thought it was pretty. We sold it as a landscaping tree for over 100 years. It became invasive and spread across the US and into Canada (map by state/province below).
Last week was hot in Pittsburgh in both temperature and humidity. On mornings when it was only 71 degrees the dewpoint was also 71 so it felt oppressive. Under the circumstances birds are scarce but insects are not.
Above, a Zabulon skipper (Lon zabulon) butterfly that was sipping on ironweed flew over to land on my thumb. It was hard to take its picture without scaring it away.
Ironweed florets are shaped like tubes, perfect for the skipper’s probocis.
Hickory tussock moth caterpillars are easy to find this month.
And two kinds of insects are attacking the Japanese knotweed — aphids and Japanese beetles.
It is very fitting that an invasive Japanese beetle eats an invasive Japanese plant.
The birds stopped singing weeks ago but the air is filled with the sound of bugs. One of them is the red-headed bush cricket (Phyllopalpus pulchellus) otherwise known as the Handsome Trig.
If you find a handsome trig you can see the beauty that gave him his name. Unfortunately he’s so tiny that we rarely see him.
However, you can hear him. He sings very loudly at 7000 Hertz, often from a Japanese honeysuckle thicket.
I say “You can hear him” because I cannot. I’ve lost my hearing above 6,000 Hertz so I view his voice as a spectrogram on the Spectroid app. The very bright white-orange stripe at 7406 Hertz is the LOUD sound of the handsome trig in the video above. The fainter line at 4,000 hertz is quieter and the only part of his sound that I can hear.
Listen for this handsome bug.
Tell me if he’s loud. 🙂
(photo from Wikimedia Commons, videos embedded from YouTube; click on the captions or the YouTube logo to see the originals)