Nematocampa resistaria
In 3 days ~10% in a week ~20%
Nematocampa resistaria, the filament bearer, bordered thorn or horned spanworm moth, is a moth of the family Geometridae. The species was first described by Gottlieb August Wilhelm Herrich-Schäffer in 1856. It is found in North America from British Columbia to Nova Scotia, south to Florida and California.
This species was split from the Eurasian Nematocampa limbata. The wingspan is 19–25 mm. Adults are on wing from May (or April in the deep south) to August. There is one generation in the north, two generations in the middle states and multiple generations in the southern part of the range.
Larvae feed on various deciduous and coniferous trees and shrubs, including Pseudotsuga, Tsuga, Abies, Picea, Salix, Betula papyrifera, Corylus, Fragaria and carrot (Daucus). Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Glacier National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Austin | 🇺🇸 United States | |
| 2 | Toronto | 🇨🇦 Canada | |
| 3 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 4 | Boston | 🇺🇸 United States | |
| 5 | Edmonton | 🇨🇦 Canada | |
| 6 | Chicago | 🇺🇸 United States | |
| 7 | Houston | 🇺🇸 United States | |
| 8 | Montreal | 🇨🇦 Canada | |
| 9 | New York City | 🇺🇸 United States | |
| 10 | San Antonio | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Horned Spanworm Moth sighting in Minneapolis [Saint Paul] on a given day, based on 16 verified sightings from GBIF citizen-science data. It is the 320th most-seen of the 672 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
June
In that month about 10% of wildlife watchers report a Horned Spanworm Moth in Minneapolis [Saint Paul] on a given day, against under 5% in July to May, the lowest months. That is one of Minneapolis [Saint Paul]'s wettest months, with about 130 mm of rain against 20 mm in January.
Between 10 pm and 1 am
Across all the parks we cover, that three-hour window holds the most Horned Spanworm Moth sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.
3rd of 11
Of the 11 cities where we can rate Horned Spanworm Moth sightings, Minneapolis [Saint Paul] ranks 3rd at under 5%. The best odds are in Austin (United States, about 10%) and Toronto (Canada, under 5%).
Same family: Geometridae
The closest relatives of the Horned Spanworm Moth that you can see in Minneapolis [Saint Paul] (family Geometridae, Geometer Moths) are Chickweed Geometer Moth (about 10%), Lesser Maple Spanworm Moth (about 10%) and Fall Cankerworm Moth (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Horned Spanworm Moth is recorded against all the insects logged in Minneapolis [Saint Paul] (16 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.
