"What a thousand acres of Silphiums looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked." -Aldo Leopold
Today’s caterpillar is from another monotypic genus in the family Sphingidae. The pawpaw sphinx (Dolba hyloeus) hosts not only on pawpaw (Asimina triloba), but also on hollies-Ilex and blueberries-Vaccinium. This animal was found on A. triloba in early August at Babler State Park in St. Louis County, MO.
Today’s caterpillar is a little confusing in a a couple of ways. This individual is either Erynnis juvenalis (Juvenal’s duskywing) or E. horatius (Horace’s duskywing). Both species look pretty much identical as larva and both use several oak species as host plants. I’m no expert but it seems that these are best identified to species in their adult form.
The second confusing thing is that I found this individual while beat-sheeting a small ash tree (Fraxinus sp.) in mid-July at Onondaga Cave State Park in Crawford County, MO. From my understanding, both species are obligate oak feeders. This might mean it had fallen from a higher oak and landed in the ash tree, or it might be pre-pupal and looking for a place to pupate. Most often Caterpillars move from their host plants to pupate in a neighboring tree or plant.
If you have any thoughts or tips on how I might discern this guy to species with just a couple of simple photos and the information I supplied, please let me know.
For tonight’s caterpillar, I am featuring the Sphingidae family member, Amorpha juglandis – the walnut sphinx moth. This is the only species in the monotypic genus, Amorpha, a name that is shared with a plant genus that holds our leadplant (Amorpha canescens) and false indigo bush (A. fruticosa). This name comes from the Greek – amorphos- meaning formless or mishappen. This describes the lack of wing and keel petals of the corolla of these beans. For the moth, I am not completely certain, but it may have to do with the unique shape and placement of the rear wings when this moth is at rest. This species is very easily identified in both larval and adult forms.
First up are a couple of early instar brood mates that I found on the same walnut tree in mid-July at Kaintuck Hollow in Phelps County, MO.
Next up is an older cat found at Schoolcraft Prairie in Washington County, MO in mid-August. Caterpillars of this species at this stage are infamous for its defensive displays when harassed, including emitting a high-pitched squeak, thrashing and biting. Unfortunately, this one was pretty chill, so I could not show this off to the folks I was with.
Finally, on the same night we photographed the caterpillar pictured immediately above, an adult male moth was attracted to our blacklight setup. This was my first looks at the adult form of this species.
Tonight’s caterpillar is a member of the Crambidae family – Saucrobotys futilalis, or the “dogbane saucrobotys moth.” The host for this species is the namesake dogbane (Apocynum species) and they can also feed on milkweeds (Asclepias species). I found these pretty easy to find in mid to late July at Don Robinson State Park by simply looking for their web nests within dogbane plants. There were usually several cats within each nest and a little beating of the plants could get quite a few tumbling out.
I find the Latin binomial for this one to be pretty entertaining. Saucro, coming from the Greek for graceful, pretty and beauty, along with botys, the genus to which this moth was originally ascribed. While, on the other hand, the specific futilalis seems to come from the Latin futilis, meaning brittle, vain, or worthless. Taxonomic nomenclature can be confusing and is often steeped in history (this species was described in 1863), but I find this grouping to be pretty entertaining.
Today’s cat is in the Pyralidae family. It is most likely Pococera expandens (double-humped pococera moth), but with at least 27 species in this genus and many of which that feed on oak, upon which this one was found, other species could be an option. This guy was photographed in early July during a WGNSS Nature Photography field trip at Prairie Garden Trust in Calloway County, MO.
Today I am showcasing an example of biological pest control that I came across in my own neighborhood in late April of this year. The image below shows a bronzed cutworm moth larvae (Nephelodes minians) in the Family Noctuidae that has been parasitized by a Braconid wasp in the genus Cotesia. This is a very species-rich genus of parasitoids, but there is a fair chance of this species being C. marginiventris. Thanks very much to Alex Soohoo-Hui for his assistance in narrowing down the identification of this minute wasp.
The bronzed cutworm is a very common moth that feeds on various grasses, including crops like maize and other cereals as well as turf grasses. I consistently find these cats or their chrysalis whenever I dig a new hole in the yard.
After the wasp deposits her eggs on the host, the wasp larvae feed on the caterpillar internally, being careful not to do much damage to vital organs. The host will never survive, but the parasitoids must ensure that it stays alive long enough for the brood to reach maturity. Often, the caterpillar will still be alive when the wasp larvae emerge and begin to spin their cocoons and will defend itself and its parasites from potential predators.
In this case, the caterpillar seemed dead. I collected it and took it home with hopes of rearing out the tiny wasps to photograph and identify. In about four days, I came home to find 15-20 adult wasps had emerged.
The adult wasps are extremely tiny, measuring 2-3 mm. In order to have a chance at getting photographs, I placed their enclosure into the refrigerator for a minute or two. The wasps in the accompanying images might appear dead, but they perked up within a couple of minutes. After getting my photographs, I released the brood into my backyard to continue their pest control services.
A couple more looks at this diminutive but effective parasitoid.
A few miscellaneous arthropods from 2023.
In February, the Webster Groves nature Study Society’s Nature Photography Group headed to the Sophia M. Sachs Butterfly House in Chesterfield. We paid for after-hours access and were delighted with the opportunities presented to us. Many thanks to Casey Galvin, group leader for the Nature Photography Group, for organizing this visit, and to Chris Hartley from the Butterfly House for being a lovely host. Chris patiently dealt with our needs, requests and questions, while wrangling our subjects for us. He and the Butterfly House provided us a wonderful experience of photographing some remarkable arthropods from around the world. Here are some of my favorite photos from the evening.
That’s all from this outing. Interested in joining in one one of these WGNSS outings? Feel free to contact me or check us out at http://www.wgnss.org to learn more.
-OZB
Here are a few handsome Orthopterans from the 2023 season.
Today I’m finishing up with the remaining cats of late summer and autumn hunting trips of 2023 from an assortment of families.
Walnut Sphinx Moth (Amorpha juglandis) Sphingidae, Hodges#7287
These are among my favorites. Not only are they quite handsome when viewed up close, but they are one of the few caterpillars with a voice! Be prepared if you handle or otherwise disturb them; they will let out a surprising squeak when they feel threatened.
Curve-lined Angle (Diagrammia continuata) Geometridae, Hodges#6362
Casey and I observed that the juniper hairstreaks (Callophrys gryneus) had a bumper year this year while hiking in glades early in the season. We thought this might be the year to finally find the fantastic larvae of this species. We spent several hours beat-sheeting the red cedars in these areas in late summer and early fall. No luck in finding that species, but we did find another inconspicuous cat that uses this plant as its host. You can probably see that, like the hairstreak, the caterpillars of this moth species would be next to impossible to find without the use of a beat-sheet.
Undescribed Flower Moth (Schinia nr-jaguarina) Noctuidae, Hodges#11132.01
I shared photos of this yet to be described species before. These are photos of the cats we found at a new location, Horn’s Prairie Grove LWR, in central Illinois.
Red-lined Panopoda (Panopoda rufimargo) Erebidae, Hodges#8587
An interesting cat we found while beet-sheeting a hickory thicket on a friend’s property in St. Francois County.
Pipevine Swallowtail (Battus philenor) Papilionoidea
Conspicuous and distasteful due to the absorbed secondary chemicals of their pipevine host, it seems like we always find these guys in low-light situations, making the use of supplemental light a necessity.
Giant Swallowtail (Papilio cresphontes) Papilionoidea
My favorite swallowtail species. It was a real treat finding this final instar cat back in September.
A Thousand Acres of Silphiums 