Pearl crescent butterfly, Raccoon Creek Wildflower Reserve, 18 July 2026 (photo by Kate St. John)

25 July 2026

July is Bug Season. This week they took center stage at Raccoon Wildflower Reserve, Frick Park and Aspinwall Riverfront Park (a.k.a. Allegheny RiverTrail Park).

Butterflies are hard to photograph with my cellphone but I managed to capture images of a pearl crescent at Raccoon Wildflower Reserve.

Pearl crescent butterfly, Raccoon Creek Wildflower Reserve, 18 July 2026 (photo by Kate St. John)

Looks like a bee but this is a fly — a bee-fly on Queen Anne’s lace at Aspinwall.

Bee-fly on Queen Anne’s lace, Aspinwall Riverfront Park, 22 July 2026 (photo by Kate St. John)

I also found evidence of tiny wasps and chased a Great-sized wasp from flower to flower.

At Frick Park we found a red misshapen gall on a blackberry stem. Not only did the gall look like an infection but the stem looked like it had broken at the site of the gall. This is evidence of a blackberry knot gall wasp (Diastrophus nebulosus).

Evidence of the blackberry knot gall wasp, Frick Park, 21 July 2026 (photo by Kate St. John)

The wasp is a blackberry stem specialist. It doesn’t use other plants.

Evidence of the blackberry knot gall wasp, Frick Park, 21 July 2026 (photo by Kate St. John)

Inside the gall are the tiny larvae of Diastrophus nebulosus that irritate the plant so much that it produces a big gall. The adults are tiny too — a little smaller than a sesame seed.

Blackberry know gall wasp, Diastrophus nebulosus (photo from Wikimedia)

On the high end of the size spectrum are great digger wasps. I found a great black digger wasp (Sphex pensylvanicus) at Aspinwall Riverfront Park. Though “Pennsylvania” is in their name these wasps have a wide range in North America.

Great black digger wasp on slender mountain mint, Aspinwall Riverfront Park, 22 July 2026 (photo by Kate St. John)

Like most wasps, great black digger wasps are solitary.  The female makes her nest by digging a hole with lateral chambers.  To provision the chambers she captures and paralyzes a katydid or grasshopper and then lays an egg on it. When the egg hatches the larva feasts on the paralyzed (live) insect and emerges as a wasp.  Read more about it here.

Great black digger wasp on slender mountain mint, Aspinwall Riverfront Park, 22 July 2026 (photo by Kate St. John

There are other colors of digger wasp. I saw a great golden digger wasp 13 years ago at the Montour Trail. Late July seems to be their favorite time in southwestern PA.

Great golden digger wasp, Montour Trail, 21 July 2013 (photo by Kate St. John)