Synanthedon exitiosa, Peachtree Borer/Clearwing Moth

CORRECTION 2014-07-27: ID’d by William H. Taft on BugGuide as a male S. exitiosa, not S. fatifera, Arrowwood Borer, as I thought.


A lifer for me. I never even knew such a thing existed.

Synanthedon exitiosa, Peachtree Borer/Clearwing Moth, male, on Pycnanthemum muticum, Clustered Mountain Mint, in my garden yesterday afternoon.

I was showing a visitor all the pollinator activity on the Pycnanthemum. I identified 8 different bee species in less than a minute. Then I saw … THAT.

Synanthedon fatifera, Lesser Viburnum Clearwing Moth, on Pycnanthemum muticum, Clustered Mountain Mint, Flatbush, Brooklyn, July 2014

In my peripheral vision I thought it might be a wasp from the general shape and glossiness. Once I focussed on it, I recognized it as a moth.

How did I get “moth” from that?!

  • Body shape: It doesn’t have any narrowing along the body, which wasps and bees have.
  • Eyes: Large round eyes on the sides of the head, unlike the “wraparounds” of bees and wasps.
  • Antenna: They just looked “mothy” to me.

It was nectaring on Pycnanthemum muticum, Clustered Mountain Mint, in my garden. This patch of Pycnanthemum is just a few feet from the large Viburnum dentatum, Arrowwood, in my garden.

I’ve seen other Clearwing Moths, Sesiidae, so that gave me something to search on. The slender body was something I’d never seen before. Comparing with other images of Clearwing Moths, I was able to narrow it down to the genus Synanthedon. Then I used BugGuide and other authoritative sources to compare the coloration of the body and legs, and the markings on the wings, to key it out to species.

2014-07-24: But my original specific identification was incorrect! William H. Taft commented on one of my photos (the first in this blog post) on BugGuide that the amber color of the wings is a key to distinguishing S. exitiosa from S. fatifera. The BugGuide species page notes the yellow bands of “hairs” at the joints between the body segments. But the comparison species are other Peachtree Borers, not Arrowwood Borer, so I missed the comparison.

Looking at other photos of male Peachtree Borers, they look more like my find than Arrowwood Borer. Markings on the wings appear to be variable, not as diagnostic as I’d assumed. This is a lesson for me to be more conservative in my identification, and rely more on diagnostic keys than naive visual comparisons.

Oblique shot, showing the wing markings and venation.

Another common name for this species is Arrowwood Borer. It seems likely that this adult either just emerged from my shrub, or was attracted to it. I’ll look to see if I can find any borers still in the shrub.

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Atteva aurea, Ailanthus Webworm Moth

Atteva aurea, Ailanthus Webworm Moth, on Pycnanthemum, Mountain-Mint, in my garden last weekend. The intense colors are believed to be aposematic, a warning coloration to deter predators, probably because they would be distasteful.
Atteva aurea, Ailanthus Webworm Moth, on Pycnanthemum, Mountain-Mint

The larvae – caterpillars – feed in communal aggregations, like tent caterpillars. Around the globe, caterpillars in the genus Atteva are known to feed on plants from at least a half-dozen plant families. But they favor plants in the Simaroubaceae, the Quassia Family.


The Quassia Family includes the infamous invasive tree, Ailanthus altissima, Tree-of-heaven, probably best known as “that tree what grew in Brooklyn.” So, as Ailanthus has invaded here, Atteva aurea discovered a new suitable host. It’s likely this has supported an increase in its numbers, and possibly its range, from its original native populations.

Atteva aurea, Ailanthus Webworm Moth, on Pycnanthemum, Mountain-Mint

Atteva aurea, Ailanthus Webworm Moth, on Pycnanthemum, Mountain-Mint

Atteva aurea, Ailanthus Webworm Moth, on Pycnanthemum, Mountain-Mint

Taxonomic notes

Atteva is the sole genus in the subfamiuly Attevinae, the Tropical Ermine Moths, of the lovely-named family Yponomeutidae, the Ermine Moths. “Ermine” because the moths’ coloration resembles that of the spotted forms of the coat of the Ermine, Mustela erminea. This is a photo of another Ermine Moth, Yponomeuta evonymella, showing the classic “ermine” pattern of that species. Image ©entomart, via Wikipedia/Wikimedia.

Per BugGuide, the family name, and the genus from which it arises, is likely a typographic error:

Family is named for genus Yponomeuta Latreille, 1796. That name was apparently a typographic error (!) for Hyponomeuta. That would be a combination of Greek prefix hypo under, plus nomeuta (unknown, perhaps from Greek pno air; breathing, plus meuta?)

The many ecotypes across the wide range of this species give rise to variations of color patterns. These variants have identified under many different specific epithets, and even other genera. (BugGuide notes: “This moth belongs to a species complex that was recently split”). Because of this, searching taxonomic-based resources, such as the Caterpillar Host Plants Database,  for this species may not identify all relevant records.

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Flickr photo set

Links

BugGuide
BAMONA
Wikipedia
HOSTS Database: Genus Atteva
The Plant List: Simaroubaceae
USDA Plants: Ailanthus altissima