Xestia normanianus, a dart moth, nectaring on lance-leaved aster (Symphyotrichum lanceolatum) at night.
What do moths do at night anyway? Some of them visit flowers for nectar.
Back in August, I was wandering about in the woods at night looking for foxfire fungi. At the head of the trail on my way out, I saw a sunflower plant with something on the flowers. It was a green tree cricket (Oecanthus) eating the stamens in the sunflower florets.
The next night, I went back but this time with my camera, hoping to find more tree crickets. I had my LED headlamp on like the previous night and used it to illuminate the flowers and foliage where I wanted to photograph. I also set the flash of my camera to “on”.
Although I could hear tree crickets in the bushes, I didn’t see any this time. What I did see were lots of moths on sunflowers and asters. Aiming the lamp’s beam at the flowers, I then pointed my camera at the moths and began taking photos. I wasn’t using a tripod, so many were blurry. Some were also overexposed by the bright LED light. But a few turned out.
Feltia jaculifera nectaring on a sawtooth sunflower (Helianthus grosseratus)Nephelodes minians nectaring on a sawtooth sunflower (Helianthus grosseratus)
The moth species (Xestia normanianus, Feltia jaculifera, and Nephelodes minians) I found on flowers at night came as no surprise. These and other dart moth species are common visitors to my moth lights. But it was exciting to see them going about their normal activities in a natural setting. I never did find any foxfire this year.
Moths weren’t the only visitors to flowers at night. I wonder if this crab spider was sleeping or waiting for a moth.
Three species of syrphid flies on sunflowers. Eristalis dimidiata (upper right), Eristalis transversa (lower right), and maybe a Syrphus sp. (upper left).
This was an unusual sight. Three species of syrphids, each on a separate wild sunflower head, are getting a meal of pollen and nectar. Two of the species I could identify are Eristalis dimidiata (upper right) and Eristalis transversa (lower right). The third one in the upper left didn’t show enough details. I could only place it as possibly a Syrphus sp.
A swarm of bees?
I first got interested in syrphid flies about two decades ago when I was doing an inventory of plant species in a fen. Suddenly, I became aware of what sounded like a swarm of bees in a large patch of nodding bur-marigold and asters. To my relief, they were not bees but hundreds of syrphid flies nectaring at the flowers. Over the years, I’ve gradually learned more about these bee-like insects and their importance.
Bidens cernua (Nodding Bur-Marigold) in early September, flourishing in a restored fen.
When to see them
Late summer is one of the best times to observe syrphid flies. You can see them on sunflowers, coneflowers, goldenrods, joe-pye-weed, bur-marigolds, and asters, all members of the aster family. Buzzing loudly, they go from flower to flower like bees, and with the bees, in search of pollen and nectar.
A wet meadow in late August carpeted with joe-pye-weed (Eupatorium maculatum) and smooth goldenrod (Solidago gigantea). Perfect foraging habitat for syrphids and other pollinators.
Syrphid flies can also be seen in spring and early summer. But to see them, you may need to go into the woods. Some of these forest-dwelling species can be attracted to sugary baits painted on tree trunks or boards attached to posts. They can also be found on woodland wildflowers like Canada mayflower.
Bee and wasp mimics
Many syrphids have body patterns and body shapes that resemble those of bees and wasps. This mimicry (Batesian mimicry) is a form of camouflage to deter potential predators. The resemblance to wasps and bees is striking.
Physocephala furcillata, Eumenes crucifera, and Doros aequalis resemble potter’s wasps, and Ocyptamus fascipennis, an ichneumon. Sericomyia chrysotoxoides looks like a yellow jacket wasp, and Eristalis flavipes could be mistaken for a bumblebee.
Sericomyia chrysotoxoides (Oblique-banded Pond Fly), a yellow jacket wasp mimic. The larvae live in mud rich in organic matter, filtering out microorganisms.Doros aequalis, an Ancistrocerus mimic, lives in forests. It’s a pollinator of spring ephemerals. The larvae live in ant nests and eat aphids.Eristalis flavipes (orange-legged drone fly), a bumblebee mimic. Its larvae feed on small organisms in stagnant water.
Syrphids are pollinators
Like bees, syrphids are pollinating insects. But it is not just aster family plants they seek out. I have seen syrphids on mustard (Brassica nigra), amaranth (Amaranthus cruentus), milkweed (Asclepias syriaca), purple prairie clover (Dalea purpurea), grass-of-parnassus (Parnassia sp.), and cinquefoil (Potentilla recta).
Physocephala furcillata on milkweed (Asclepias syriaca) flowers. This species is a wasp mimic incorporating features of Eumenes potter wasps.Probably Eupeodes (Metasyrphus) americanus on the flower of a mustard plant (Brassica nigra). The fly resembles a small yellow jacket wasp.Ocyptamus fascipennis on amaranth (Amaranthus cruentus). This species is an an ichneumon wasp mimic.Toxomerus marginatuson cinquefoil (Potentilla recta) flower.Toxomerus geminatus on purple prairie clover (Dalea purpurea).Toxomerus marginatus on a Parnassia flower.
Syrphid fly larva on an aster leafSyrphid fly larva on a willow leaf
Encouraging syrphids
Syrphid flies, like the bees and wasps they often mimic, are important parts of the pollinator fauna. They don’t sting or bite, but their appearances can give you pause.
Planting nectar-rich domesticated plants like buckwheat, sunflowers, coriander, and dill, and wildflowers. Even small patches will help them. From there, they can launch forays into gardens and fields, pollinating crop plants. Predatory species will lay eggs that hatch into maggots that eat pest insects like aphids, scale insects, and spider mites.
In an earlier post, I wrote about Lophocampa maculata, a moth in the Arctiinae, distinguished by its fuzzy black and yellow larvae. These larvae later metamorphose into beautiful adult moths with a contrasting pattern of alternating bands of warm, muted golden-orange and darker brown markings with a reddish-orange tinge. In this post, I write about Halysidota tessellaris, the banded tussock moth, another moth in the Arctiinae.
Halysidota tessellaris caterpillar feeding on a crabapple leaf in late summer.
Identification
Like Lophocampa maculata, the larvae of Halysidota tessellaris are also fuzzy, but they are usually gray to dingy brown with long white and long black tassels. The adult moth, while similar in size to Lophocampa maculata, has translucent yellow forewings marked with slightly darker bands and irregularly shaped block-like cells that form a tessellated pattern. Also, there are two parallel blue stripes on the fuzzy thorax.
Life cycle
Across its range, larvae of Halysidota tessellaris feed on many species of hardwood tree leaves. Among these are box elder (Acer negundo), sweet birch (Betula lenta), ash (Fraxinus spp.), oaks (Quercus spp.), and many others. Adult moths take nectar and are pollinators of milkweeds (Frost, S. W. (1965) Insects and Pollinia. Ecology, 46. 556-558, paywall).
Halysidota tessellaris, a worn specimen, but the blue lines are prominent.Halysidota tessellaris showing the tessellated pattern of the forewings.
Similar species
Adults of the related Halysidota harrisii (sycamore tussock moth) are similar in appearance to Halysidota tessellaris. Where the ranges of Halysidota tessellaris and Halysidota harrisii overlap, genital dissection is necessary to determine the species. Halysidota harrisii larvae, which may be solid white, yellow, orange, or gray, feed exclusively on sycamore (Platanus occidentalis) leaves. The ranges of sycamore and the moth coincide closely.
Not Very Far Away 