Eriocampa juglandis
In 3 days ~10% in a week ~30%
Eriocampa juglandis, the butternut woollyworm, is a species of sawfly that lives and feeds on butternuts, black walnuts and hickory. It is in the Hymenoptera order, that of ants, wasps, and bees. The larvae will grow to 0.87 inches (22 mm) long and the adult sawfly is 0.47 in (12 mm). The young of this species is covered in white wool which is believed to protect it from predators. Though the larva resembles a caterpillar, sawfly larvae have a pair of legs for every body segment, while caterpillars have a gap between some legs. Sawflies often curl up when disturbed.
The adult is a flying insect with a saw-toothed ovipositor, giving the genus its common name. Females saw into the mid-rib of leaflets and deposit 20 to 30 eggs, one at a time, which eventually causes the leaflet to droop or fold and the midrib to turn pale. While small larvae chew random holes in leaves, larger ones may finish them off entirely, leaving bits of the larger veins behind. Once fully grown larvae pupate in the soil throughout the winter until spring when they reemerge as adults and mate.
The range of this insect follows the historical range of the butternut... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Washington | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Butternut Woollyworm Sawfly sighting in Great Smoky Mountains National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 513th most-seen of the 822 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
August and September
In those months about 10% of wildlife watchers report a Butternut Woollyworm Sawfly in Great Smoky Mountains National Park on a given day, against under 5% in October to July, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Butternut Woollyworm Sawfly sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Great Smoky Mountains National Park, in our data
Great Smoky Mountains National Park is the only park on Wallace's Line with enough records to rate Butternut Woollyworm Sawfly sightings: under 5% of wildlife watchers there report one on a given day.
Same order: Hymenoptera
The closest relatives of the Butternut Woollyworm Sawfly that you can see in Great Smoky Mountains National Park (order Hymenoptera, Ants, Bees, Wasps, and Sawflies) are Common Eastern Bumble Bee (about 40%), Eastern Carpenter Bee (about 30%) and European Hornet (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Butternut Woollyworm Sawfly is recorded against all the insects logged in Great Smoky Mountains National Park (7 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
