Megacyllene robiniae
In 3 days ~20% in a week ~40%
Megacyllene robiniae, commonly known as the locust borer, is a species of longhorn beetle endemic to eastern North America. It is a serious pest of Robinia pseudoacacia, the black locust tree, with which it is sympatric.
The specific name, robiniae, is derived from the name Robinia, which is the generic name of the black locust tree, Robinia pseudoacacia, on which the larvae feed. The name Robinia was coined by Linnaeus to honor the royal French gardeners Jean Robin (father) and Vespasien Robin (son).
From a distance, M. robiniae can easily be mistaken for a wasp or bee, due to its black and yellow striped pattern. It can also be mistaken for two closely related species: M. caryae and M. decora. The adult beetle can be 11 to 28 mm (0.43 to 1.10 in) long, and it has a W-shaped third stripe on the elytra. The antennae of both sexes are dark brown to black. The male's antennae are two-thirds its body length, and the female's are one-half. The legs are reddish brown. The full grown larvae are legless, white, and robust, growing to roughly 25 mm (0.98 in) long.
Because there has been increasing use of R. pseudoacacia as... 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 | Boston | 🇺🇸 United States | |
| 2 | Montreal | 🇨🇦 Canada | |
| 3 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 4 | Salt Lake City | 🇺🇸 United States | |
| 5 | Toronto | 🇨🇦 Canada | |
| 6 | Detroit | 🇺🇸 United States | |
| 7 | Denver | 🇺🇸 United States | |
| 8 | Philadelphia | 🇺🇸 United States | |
| 9 | Portland | 🇺🇸 United States | |
| 10 | New York City | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Locust Borer sighting in Great Smoky Mountains National Park on a given day, based on 27 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 202nd most-seen of the 822 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
September
In that month about 30% of wildlife watchers report a Locust Borer in Great Smoky Mountains National Park on a given day, against under 5% in November to July, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Locust Borer sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 2
Of the 2 parks where we can rate Locust Borer sightings, Great Smoky Mountains National Park ranks 2nd at about 10%. The best odds are in Shenandoah National Park (United States, about 20%).
Same family: Cerambycidae
The closest relatives of the Locust Borer that you can see in Great Smoky Mountains National Park (family Cerambycidae, Longhorn Beetles) are Broad-Necked Root Borer (about 20%), Strangalepta Flower Longhorn Beetle (about 10%) and Eastern Elderberry Borer (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Locust Borer is recorded against all the insects logged in Great Smoky Mountains National Park (27 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.
