19 August 2025

Last Thursday Charity Kheshgi and I were on a narrow trail at Frick Park when we had to stop because a big black wasp was flying back and forth over the trail, sometimes landing and wiggling her antennae on the ground, then flying again in front of us. Charity got a photo of her on the ground. Why won’t she leave?

While we waited I googled “black wasp with yellow antennae, orange-tipped wings” and found out she was a spider wasp, probably Entypus unifasciatus pictured below. She was doing something really creepy and we shouldn’t get too close.

“Female spider wasps [E. unifasciatus] hunt for wolf spiders to provision their nests, which they often create in pre-existing cavities or burrows.” — paraphrased from Missouri Dept of Conservation.

Wolf spiders fight the attacking wasp but she flies up to avoid his reach, then stings him and injects her paralyzing venom.

Because of camouflage it took us a while to realize that this wasp had a victim. She turned the paralyzed spider to make sure he was immobile, then grabbed him with her jaws, dragged him backwards down the trail and disappeared into the weeds where she’d established a burrow.

This photo by Lafe on Flickr shows a spider wasp dragging a wolf spider across his lawn.

At this point the wolf spider is alive but cannot move. Inside her nest …

At the end of [her] burrow is a deep cell or chamber carved out in advance by the female. While depositing the spider there, she lays a fertilized egg [on its body]. Once her egg hatches, the larva begins eating the spider while it is alive, but still paralyzed. Once the larva grows large enough, it pupates in this cell over the winter, and emerges as a winged adult in the early summer. …

Because females lay many eggs in a season, they must collect multiple spiders as food stores. This usually means that their appearance is a bit haggard and worn out by the end of summer thanks to many victorious battles. 

— Insect Identification: Spider Wasp (Entypus unifasciatus)

Creepy.

7 August 2025

Today a quiz that you face every day during Bug Season: Is this a Moth or a Butterfly?

These 11 photographs are moths and butterflies from Wikimedia Commons. The experts among you will be able to identify the species, but not all of them because some are from other continents and some have no location description. If you click on the caption links you’ll see the original photo with description … BUT … some of the descriptions are mislabeled.

Clues to help you:

• Antennae: Feathery (moths) vs Knobs (butterflies) … and then there are skippers
• Flying: Night (moths) vs Day (butterflies): But there are exceptions. However some of the photo backgrounds give a clue.
• Wing Position At Rest –> see this photo … And then there are skippers.

Need help? Check out this vintage article How Do You Know It’s A Moth? and Wikipedia’s Comparison of butterflies and moths.

Try the Quiz: “Moth? or Butterfly?” Don’t forget to identify the top photo.
6:00pm Update: I’ve posted answers in the Comments.

9 July 2025 UPDATED at 3:20pm

Tiger swallowtails are one of the few butterflies I can identify so I’m always happy to see them in the city parks. I thought they were just plain “tiger swallowtails” until I learned there are not just two species (as I first wrote) but three in Pennsylvania. My thimble full of butterfly knowledge overflowed so I’m passing it along.

The eastern tiger swallowtail (Papilio glaucus) is the only species we have in Allegheny County because the Canadian tiger swallowtail (Papilio canadensis) requires a cooler climate.

In Pennsylvania P. canadensis is limited to the upper elevations so you’ll find them an hour east of us in the Laurel Highlands. However, P. glaucus is probably there too and where their ranges overlap they produce hybrids. The Appalachian tiger swallowtail (Papilio appalachiensis), the third species in PA, was originally a hybrid of those two found in the Appalachian Mountains.(*)

Compare the Canadian tiger swallowtail (Papilio canadensis) below to the eastern tiger swallowtail (Papilio glaucus) at top.

The colors in the photos may confused you but they hardly matter. Bugguide.net for Papilio canadensis explains how to tell them apart:

Adult: inner margin of P. canadensis hindwing has wide black stripe (whereas the otherwise similar – though larger – Eastern Tiger Swallowtail has a thin black stripe in that area).

Larva: mature larvae os P. canadensis are dark green, with two spots that look like eyes on the swollen section of the body behind the head; this creates a snake-like profile. Immature larvae are brown and white, resembling bird droppings (CBIF)

— Bugguide.net Papilio Canadensis account

You can see the hindwing difference in this side-by-side comparison if you look closely. This ID tip relies on the butterfly holding still, eh? If it’s hard to see in the photos, click on the image for a marked up copy outlining it.

Their larvae have slightly different food preferences may help identify them (listed below from Wikipedia).

Host plants of P. glaucus include:

Wild black cherry (Prunus serotina)
Ash (Fraxinus species)
Cottonwood (Populus species)
Wafer ash or hoptree (Ptelea trifoliata)
Common lilac (Syringa vulgaris)
Sweet bay magnolia (Magnolia virginiana)
Tulip poplar or tulip tree (Liriodendron tulipifera)
Willow (Salix species)

Host plants of P. canadensis include:

Birches (Betula sp)
Poplars, aspens, and cottonwoods (Populus sp)
Apple trees (Malus sp.)
Black cherry (Prunus serotina)

The tiger swallowtails’ range overlap and hybridization in Pennsylvania are similar to our chickadee species overlap. See Pittsburgh’s Puzzling Chickadees for the story.

(*) UPDATE on 7/9 at 3:20pm: I originally said two species but Bob Machesney pointed out there are three. See his comment about the Appalachian tiger swallowtail (Papilio appalachiensis).