Malacosoma constricta
In 3 days ~10%
Malacosoma constricta, also known as the Pacific tent caterpillar, is a species of moth endemic to North America. Malacosoma constricta is known from California, Oregon, and Washington and is reported only on oaks. In California, subspecies M. constrictum austrinum is found from Santa Barbara County southward; M. constrictum constrictum occurs from Los Angeles County northward.
Larvae feed on leaves, often defoliating affected branches. Pacific tent caterpillars spin rudimentary tents that can be up to 10 cm (3.9 in) wide. The larvae feed in groups outside the tent, entering it only to molt. Pacific tent caterpillars have speckles on the sides, orange hairs on top and grayish or cream colored hairs on the sides. The head is dark blue. Eggs, laid along sticks in clumps, are golden yellow.
According to the U.S. Forest Service, "Other than obvious aesthetic impacts, tent caterpillars typically do not cause major damage on California oaks. When present in high numbers, caterpillars may be a nuisance." Western tent caterpillars and forest tent caterpillars are also present in California oak woodlands. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sacramento | 🇺🇸 United States | |
| 2 | San Francisco | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Pacific Tent Caterpillar sighting in San Francisco on a given day, based on 12 verified sightings from GBIF citizen-science data. It is the 443rd most-seen of the 737 insects we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Pacific Tent Caterpillar in San Francisco on a given day, so our monthly data shows no clear season.
2nd of 2
Of the 2 cities where we can rate Pacific Tent Caterpillar sightings, San Francisco ranks 2nd at under 5%. The best odds are in Sacramento (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Pacific Tent Caterpillar is recorded against all the insects logged in San Francisco (12 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.
