Antheraea polyphemus – A Thousand Acres of Silphiums

2026 Caterpillar Season – Polyphemus Moth

2026 Caterpillar Season, Caterpillars of Tyson Research Center, insects, Lepidoptera, macro, wildlife, wildlife photography

Polyphemus Moth
Antheraea polyphemus (Crammer, 1777), fam. Saturniidae, P-no. 890070
Host plants: Highly polyphagous. The recorded hosts are plants in 25 families, utilizing mostly woody species.
Date found(s): July-August, 2026
Location(s) found: St. Louis and Ste. Genevieve Counties, MO
Notes: One of the more commonly found of the large saturniid caterpillars during my searches. At first glance, these caterpillars look like those of the luna moth (Actius luna). However, a few easily remembered characteristics can be used to discern these two species: 1) the head capsule of the polyphemus is textured with long setae that give it a bearded appearance, while the luna head capsule is relatively smooth; 2) luna caterpillars have a yellow subspiracular stripe that is absent in the polyphemus; 3) the transverse lines that are found on the abdominal segments of the polyphemus caterpillar run roughly through the spiracle, whereas these lines seem to separate the segments in the luna.

2025 Caterpillar Season – Polyphemus Moth

2025 Caterpillar Season, Caterpillars of Tyson Research Center, insects, Lepidoptera, macro, wildlife, wildlife photography

Polyphemus Moth
Antheraea polyphemus fam. Saturniidae (Hodges#7757)
Host plant: Found on red oak species (Quercus sp.)
Dates found: 30 August, 2025
Locations found: Tyson Research Center, St. Louis County, MO
Notes: While the caterpillars are polyphagous, feeding on a variety of woody species, adults of this moth do not feed.

2024 Caterpillar Season – Polyphemus Moth

2024 Caterpillar Season, insects, Lepidoptera, macro, wildlife, wildlife photography

A couple of friends and I went to visit some sand and gravel hill prairies in central Illinois yesterday. Although it is a delight to visit those places and their unique floral communities, we didn’t find a lot to make us pull out the cameras. We took a short break from walking through the prairies in near perfect weather for an August day and did a little cat hunting in the nearby Sand Ridge State Forest. Along with some hungry mosquitos we happened across this cute little one feeding on a species of red oak. This is the silk moth Antheraea polyphemus. This species is among the largest caterpillars to be found in our area, but this guy was pretty tiny. I believe this is a 2nd instar.

A tale of two Saturniids

macro, wildlife photography

I typically don’t have very much luck finding caterpillars of the giant silk moths from the Saturnidae family. This past season was a little more successful. I found three polyphemus moth (Antheraea polyphemus) caterpillars and Sarah found the above luna moth caterpillar during our birthday hunting trip in mid-September. Larvae of these two species look very similar, but there are a few easy characteristics than can be used to distinguish between the two.