poison ivy sawfly

Poison ivy sawfly is a common, colorful, small to medium sized, argid sawfly. It occurs in the United States east of the Great Plains. It is the only sawfly known to feed on plants in the Anacardiaceae (cashew) family. It has been researched for suitability as a biocontrol agent for poison ivy in Bermuda.

In Minnesota, adults are active mostly from June through August. They are found mostly in open disturbed areas, the same areas where its host plants are found. They visit a wide variety of flowers. The early stage (instar) larvae feed in groups (gregariously) on the underside of the leaves. They skeletonize the leaves, eating the leaf tissue and leaving only the midrib and the main veins. Later instars are solitary feeders. Until recently, the larvae were known to feed on only eastern poison ivy and poison sumac. They do not feed on western poison ivy. In 2009, larvae in southern Florida were found feeding on poisonwood (Metopium toxiferum).

Adult females are 5⁄16″ to 7⁄16″ (8.0 to 11.0 mm) in length. The body is bright orange and black.

The head is black. The antennae are black, and they have 3 segments.

The thorax has three segments, from front to back the prothorax, mesothorax, and metathorax. It is mostly orange, but the upper side is mostly black. The plate on the first segment (pronotum) is mostly black, orange only on the lateral and lower rear margins. The mesothorax is mostly black. The plate near the rear of the mesothorax, technically the mesoscutellum but usually referred in texts as the scutellum, is usually entirely orange, sometimes partly black. The metathorax is usually orange, sometimes black. The small plates covering the wing bases (tegulae) are black.

The abdomen is orange. The tips of the sheath over the ovipositor are black.

The legs are black.

The wings are uniformly darkly tinted black. The veins are black, and the opaque cell (stigma) on the leading edge is black.

The male is smaller, ¼″ to ⅜″ (7.0 to 9.0 mm) in length, but it is otherwise similar to the female.

Female total length: 5⁄16″ to 7⁄16″ (8.0 to 11.0 mm)

Male total length: ¼″ to ⅜″ (7.0 to 9.0 mm)

Wherever its host plants are found

One generation per year: June through August

Eastern poison ivy and poison sumac

Sources

24, 27, 29, 30, 82, 83.

Almost other world like looking creature...

that is what came to mind observing this poison ivy sawfly from certain angles. I found it really interesting and it had a nice color pattern to it. I could get close to it moving slowly and quietly and it just went about its business I believe feeding on something on those little flowers. It wasn’t real big or anything maybe an inch and a quarter or so in length though some online sites state they are 11mm. which is almost half an inch. This one was at least one inch or a little more in length.

I thought it was some type of wasp at first until later on.

At Frenchman’s Bluff SNA where I seen it on June 20, 2024 there is a lot of poison ivy growing in areas and that is what the larvae/poison ivy caterpillars feed on.

Poison Ivy Sawflies do not have any stinger and this creature though strange looking wasn’t aggressive and almost seemed like a gentle creature. It was the first and only time I seen one.

It may look a little strange, but anything whose larvae feed on poison ivy plants gets my approval. And it is harmless to people. I thought it was a strange looking creature at first, but found it to be harmless, very beneficial to the area I seen it at and a real educational learning experience. Cool creature.

Alfredo Colon
6/20/2024

Location: Albany, NY

Dan W. Andree
6/20/2024

Location: Frenchman’s Bluff SNA

Almost other world like looking creature... that is what came to mind observing this poison ivy sawfly from certain angles. I found it really interesting and it had a nice color pattern to it. I could get close to it moving slowly and quietly and it just went about its business I believe feeding on something on those little flowers. It wasn’t real big or anything maybe an inch and a quarter or so in length though some online sites state they are 11mm. which is almost half an inch. This one was at least one inch or a little more in length.

I thought it was some type of wasp at first until later on.

At Frenchman’s Bluff SNA where I seen it on June 20, 2024 there is a lot of poison ivy growing in areas and that is what the larvae/poison ivy caterpillars feed on.

Poison Ivy Sawflies do not have any stinger and this creature though strange looking wasn’t aggressive and almost seemed like a gentle creature. It was the first and only time I seen one.

It may look a little strange, but anything whose larvae feed on poison ivy plants gets my approval. And it is harmless to people. I thought it was a strange looking creature at first, but found it to be harmless, very beneficial to the area I seen it at and a real educational learning experience. Cool creature.