Leptinotarsa juncta
In 3 days ~10% in a week ~30%
The false potato beetle (Leptinotarsa juncta) is a beetle found primarily in the Mid-Atlantic and Southeastern United States. Its distribution extends to Maine. Adult beetles emerge from the soil in the late spring or early summer and begin breeding, and a population may go through one to three generations in a summer.
The false potato beetle feeds on solanaceous weeds such as horsenettle, Solanum carolinense. It also feeds on other solanaceous plants, such as species of ground cherry or husk tomato, Physalis spp., and bittersweet, Solanum dulcamara, but no growth and reproduction occurs when feeding on the potato, Solanum tuberosum.
L. juncta can be easily confused with its congener the Colorado potato beetle, Leptinotarsa decemlineata. While the adult false potato beetle has alternating black and white strips on its back, like the Colorado potato beetle, one of the white strips in the center of each wing cover is missing and replaced by a light brown strip. The eggs are slightly larger and fewer are found in a cluster. The hump-backed larva is similar, but with only one row of dark spots on each side. The two species are apparently incapable of crossbreeding. Of the two, only the Colorado potato beetle is a serious pest. 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 | Detroit | 🇺🇸 United States | |
| 2 | Philadelphia | 🇺🇸 United States | |
| 3 | Washington | 🇺🇸 United States | |
| 4 | Baltimore | 🇺🇸 United States | |
| 5 | Boston | 🇺🇸 United States | |
| 6 | New York City | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a False Potato Beetle sighting in Philadelphia on a given day, based on 30 verified sightings from GBIF citizen-science data. It is the 183rd most-seen of the 632 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.
May to August
In those months about 10% of wildlife watchers report a False Potato Beetle in Philadelphia on a given day, against under 5% in September to April, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most False Potato Beetle sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
2nd of 6
Of the 6 cities where we can rate False Potato Beetle sightings, Philadelphia ranks 2nd at under 5%. The best odds are in Detroit (United States, about 10%).
Same family: Chrysomelidae
The closest relatives of the False Potato Beetle that you can see in Philadelphia (family Chrysomelidae, Leaf Beetles) are Spotted Cucumber Beetle (about 10%), Dogbane Leaf Beetle (about 10%) and Pigweed Flea Beetle (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the False Potato Beetle is recorded against all the insects logged in Philadelphia (30 verified sightings), 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.
