Malacosoma californica
In 3 days ~10% in a week ~20%
Malacosoma californicum, the western tent caterpillar, is a moth of the family Lasiocampidae. It is a tent caterpillar. The Western Tent Caterpillar is found in southern Canada, the western United States, and parts of northern Mexico. There are currently six recognized subspecies of M. californicum. Western tent caterpillars are gregarious and will spend a large portion of their time with other caterpillars in silken tents constructed during their larval stage.
Western tent caterpillars are univoltine, going through a single generation per year. Adults emerge in the late summer to copulate and lay eggs. Adult moths will preferentially lay their eggs on the sunny side of their host trees. Eggs will lay in diapause over the winter and hatch the following spring. Population sizes of western tent caterpillar can reach outbreak proportions, where populations reach very high numbers and large scale defoliation occurs. Severe outbreaks can cause defoliation of host trees however, damage to trees is minimal and most trees will grow their leaves back quickly.
The mature Western Tent caterpillar pre-pupa is 4-5 centimeters long. The caterpillars are black, grey, or white with... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Glacier National Park | 🇺🇸 United States | |
| 2 | Grand Teton National Park | 🇺🇸 United States | |
| 3 | Joshua Tree National Park | 🇺🇸 United States | |
| 4 | Olympic National Park | 🇺🇸 United States | |
| 5 | Yellowstone National Park | 🇺🇸 United States | |
| 6 | Great Bear Rainforest | 🇨🇦 Canada | |
| 7 | Yosemite National Park | 🇺🇸 United States | |
| 8 | Zion National Park | 🇺🇸 United States | |
| 9 | Rocky Mountain National Park | 🇺🇸 United States | |
| 10 | Jasper National Park | 🇨🇦 Canada | |
| 11 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Western Tent Caterpillar Moth sighting in Seattle on a given day, based on 9 verified sightings from GBIF citizen-science data. It is the 295th most-seen of the 428 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.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Western Tent Caterpillar Moth in Seattle on a given day, so our monthly data shows no clear season.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Western Tent Caterpillar Moth sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 2 cities where we can rate Western Tent Caterpillar Moth sightings, Seattle ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Vancouver (Canada, under 5%).
GBIF citizen-science records
It is estimated from how often the Western Tent Caterpillar Moth is recorded against all the insects logged in Seattle (9 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.
