Arrenodes minutus
In 3 days ~20% in a week ~50%
Arrenodes is a genus of primitive weevils belonging to the family Brentidae, containing a single described species, Arrenodes minutus, commonly known as the oak timberworm. These beetles are pests of hardwoods in North America. Adult oak timberworms are shiny, elongate, and range 7 to 25 mm in length. They are reddish-brown to brownish-black in coloration, with yellow spots on their elytra. Adults display strong sexual dimorphism; females have long, slender, straight mouthparts, while males possess flattened, broadened mouthparts with large mandibles. Males are known to be aggressive and use these large mandibles for combat. These mandibles are also used in courtship. Larvae are elongate, cylindrical, white, and curved. They have three pairs of jointed legs on the thorax and one pair of prolegs near the end of the abdomen.
Oak timberworms primarily attack oak (Quercus spp.), elm (Ulmus spp.), beech (Fagus spp.), and Populus species such as aspen and poplar. They have also been documented on boxelder (Acer negundo) and honeylocust (Gleditsia triacanthos). Upland oak species such as black oak (Q. velutina) and scarlet oak (Q. coccinea) appear to be especially susceptible... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Baltimore | 🇺🇸 United States | |
| 2 | Washington | 🇺🇸 United States | |
| 3 | Boston | 🇺🇸 United States | |
| 4 | Toronto | 🇨🇦 Canada | |
| 5 | New York City | 🇺🇸 United States | |
| 6 | Chicago | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report an Oak Timberworm sighting in Shenandoah National Park on a given day, based on 20 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 185th most-seen of the 723 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 50%, if each day is a fresh chance.
May
In that month about 20% of wildlife watchers report an Oak Timberworm in Shenandoah National Park on a given day, against under 5% in August and October–March, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Oak Timberworm sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 parks where we can rate Oak Timberworm sightings, Shenandoah National Park has the highest daily chance: about 10%. Next come Great Smoky Mountains National Park (United States, about 10%).
Same order: Coleoptera
The closest relatives of the Oak Timberworm that you can see in Shenandoah National Park (order Coleoptera, Beetles) are Asian Lady Beetle (about 30%), Larger Elm Leaf Beetle (about 30%) and Seven-Spotted Lady Beetle (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Oak Timberworm is recorded against all the insects logged in Shenandoah National Park (20 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.
