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.

2026 Caterpillar Season – Eastern Tiger Swallowtail

2026 Caterpillar Season, insects, Lepidoptera, macro, wildlife, wildlife photography

Eastern Tiger Swallowtail
Papilio glaucus (Linnaeus, 1758), fam. Papilionidae, P-no. 77a0386
Host plants: Polyphagous, hosting on woody species in at least 20 families. In Missouri most commonly found on tulip tree (Liriodendron tulipifera) and black cherry (Prunus serotina).
Date found(s): 3 September, 2026
Location(s) found: Ste. Genevieve County, MO
Notes: Eastern tiger swallowtail adults come in two color phases. Males are yellow with black wing margins and black vertical striping. Females are polymorphic, exhibiting a yellow phase as well as a dark phase. This is an interesting case of Batesian mimicry—when a harmless mimic adopts the warning signals (e.g. aposematic coloration) of a toxic or unpalatable species. In this case, the dark phase females closely resemble the pipevine swallowtail that are unpalatable due to the sequestration of aristolochic acids they obtain from their host plants. Lepidopterists have discovered that the dark phase mimics are more abundant in areas with higher numbers of pipevine swallowtails, and conversely, are rarely found in areas without their distasteful models.

2026 Caterpillar Season – Black-etched Prominent

2026 Caterpillar Season, insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

Black-etched Prominent
Americerura scitiscripta (Walker, 1865), fam. Notodontidae, P-no. 930030
Host plants: Feeds on members of the Salicaceae Family, including poplars (Populus spp.) and willows (Salix spp.).
Date found(s): 26 August, 2026
Location(s) found: Logger’s Lake, Shannon County, MO
Notes: The WGNSS group came upon the individual pictured here in Shannon County in August of 2026. When it realized we discovered it, we were in for a short but thrilling experience. The caterpillar arched its long anal prolegs over its back, extruded the yellow and red portions thereby doubling their length, and then thrashed them about wildly in an obvious attempt to threaten and dissuade us. Unfortunately, this act lasted merely seconds, and it could not be coaxed into a repeat performance after we had set it up for photographs. If this method of dissuasion does not do the trick, the caterpillar can spray acid from a gland in its thorax.

2026 Caterpillar Season – Cloudless Sulphur

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Cloudless Sulphur
Phoebis sennae (Linnaeus, 1758), fam. Pieridae, P-no. 77a0435
Host plants: Hosts on members of the legume family (Fabaceae), principally senna and partridge pea (Chamaecrista fasciculata).
Date found(s): 4 August, 2026
Location(s) found: Ste. Genevieve County, MO
Notes: By looking closely at the caterpillar pictured here, you may notice that its dorsum is covered in short setae that each contain a near-microscopic drop of fluid. In a study conducted on related Pieriis caterpillars, this fluid was found to be a sticky oil substance that had a deterrent effect on predation by generalist predators like ants.

2026 Caterpillar Season – Long-winged Dagger

2026 Caterpillar Season, insects, Lepidoptera, macro, wildlife, wildlife photography

Long-winged Dagger
Acronicta longa (Guenée, 1852), fam. Noctuidae, P-no. 931485
Host plants: Reported feeding on woody species within nine plant families. In Missouri, I have found these on oak (Quercus spp.) and ash (Fraxinus spp.).
Date found(s): 22 August, 2026
Location(s) found: Meramec State Park, Franklin County, MO
Notes: Despite a species being considered a generalist across their range, individual lineages can be wildly picky eaters. In a rearing log documented on BugGuide, a citizen scientist hatched a clutch of A. longa eggs. Despite being surrounded by prime, classic host plants like oak (Quercus nigra) and cherry (Prunus sp.), the newly hatched caterpillars stubbornly refused to eat and began to starve. In a desperate last-ditch effort, the researcher offered them blueberry leaves (Vaccinium sp.). The caterpillars immediately devoured them, proving that while the species is a generalist, individual populations may dynamically “lock into” specific regional hosts.

2026 Caterpillar Season – Green Leuconycta

2026 Caterpillar Season, insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

Green Leuconycta
Leuconycta diphteroides (Guenée, 1852), fam. Noctuidae, P-no. 932026
Host plant (s): Hosts on a variety of Asteraceae family members including fleabane (Erigeron spp) and goldenrod (Solidago spp).
Date found(s): 28 June, 2026
Location(s) found: Pinewoods Lake Recreation Area, Carter County, MO
Notes: Due to its host plant preferences, look for this moth in meadows, fields and prairies. If you plant native composite wildflowers, you may even have luck in finding them in your own backyard. The adult moth is a stunner and is often a popular subject when arriving at blacklights. It has received a common nickname in mothing circles—the “mint chocolate chip moth.”

2026 Caterpillar Season – Azalea Sphinx

2026 Caterpillar Season, insects, Lepidoptera, macro, wildlife, wildlife photography

Azalea Sphinx
Darapsa choerilus (Cramer, 1779) P-no. 890208
Host plant: Roseshell azalea (Rhododendron prinophyllum)
Date found(s): 4 August, 2026
Location(s) found: Hawn State Park, Ste. Genevieve County, MO
Notes: Azalea sphinx moth caterpillars can be found during the daytime clinging to the midvein on leaves of their azalea hosts. In their disturbance pose, as seen in the fourth-instar caterpillar pictured here, I found them remarkably similar in appearance and size to the green developing fruits of the azalea.

2026 Caterpillar Season – Black-waved Flannel Moth

2026 Caterpillar Season, insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

Black-waved Flannel Moth
Megalopyge crispata (Packard, 1864) P-no. 57a0038
Host plant: Not recorded
Date found(s): 16 August, 2026
Location(s) found: Loggers Lake, Shannon County, MO
Notes: In early to mid-August we found an abundance of these mid-instar black-waved flannel moth larva, literally dozens in this timespan. I got used to pretty much ignoring them, but recording them and the variety of hosta plants these generalists use. During a WGNSS trip, it was discovered that one of these was a bit more interesting than the others. In its downy white fluff, it held some sort of eggs. We pulled out the high magnification lenses to make sure we had a good chance at identifying these back home. Eggs of some parasitoid first came to mind, but these did not match anything obvious with those groups. After a Google session, we found these are most likely eggs of an assassin bug (fam. Reduviidae). It is unknown how or why the eggs found their way onto the caterpillar as assassin bugs typically oviposit on the surfaces of plants. Either the assassin bug chose a weird location to oviposit or perhaps the caterpillar collected these when moving about.

Mid-instar *Megalopyge crispata* larvae with Reduviidae eggs

2026 Caterpillar Season – Elm Sphinx

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

Elm Sphinx (Four-horned Sphinx)
Ceratomia amyntor (Geyer, 1835) P-no. 890102
Host plant: Found on American elm (Ulmus americana)
Date found(s): July–August, 2026
Location(s) found: Carter County, MO, Ste. Genevieve County, MO; St. Louis County, MO
Notes: An excellent example of camouflage. The four thoracic horns aptly mimic the teeth on the margins of the leaves on which they feed. These larva spend most of their time hiding upside-down on the undersides of elm leaves. The pale, oblique lines leading from the stomata to the mid-dorsal line let them blend in with elm leaves that feature prominent pinnate venation on their undersides (see photo).

2026 Caterpillar Season – Blinded Sphinx

2026 Caterpillar Season, insects, Lepidoptera, macro, wildlife, wildlife photography

Blinded Sphinx
Paonias excaecata (J.E.Smith, 1797) P-no. 890144
Host plant: Found on black cherry (Prunus serotina)
Date found: 5 August, 2026
Location found: Ste. Genevieve County, MO
Notes: Note the red blotches that are surrounded by yellow, nicely mimicking later season leaves. This undoubtedly provides nice camouflage and may explain why certain color morphs are found on certain hosts.