Andricus quercuscalifornicus
In 3 days ~60% in a week ~90%
Andricus quercuscalifornicus (occasionally Andricus californicus), or the California gall wasp, is a small wasp species that induces oak apple galls on white oaks, primarily the valley oak (Quercus lobata) but also other species such as Quercus berberidifolia, and Quercus garryana in Oregon. The California gall wasp is considered an ecosystem engineer, capable of manipulating the growth of galls for their own development. It is found from Washington, Oregon, and California to northern regions of Mexico. Often multiple wasps in different life stages occupy the same gall. The induced galls help establish complex insect communities, promoting the diversification in niche differentiation. Furthermore, the adaptive value of these galls could be attributed their ecological benefits such as nutrition, provision of microenvironment, and enemy avoidance.
The adult wasps are small, stout and brown, about 5 mm long with clear wings nearly twice the length of the body. The antennae are filiform and about the same length as the legs. Despite their size they are one of the largest species of cynipid wasps.
The gall itself is a typical oak apple gall in appearance, roughly spherical... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States | |
| 2 | Joshua Tree National Park | 🇺🇸 United States | |
| 3 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sacramento | 🇺🇸 United States | |
| 2 | San Francisco | 🇺🇸 United States | |
| 3 | Portland | 🇺🇸 United States | |
| 4 | San Diego | 🇺🇸 United States | |
| 5 | Los Angeles | 🇺🇸 United States | |
| 6 | Seattle | 🇺🇸 United States |
Possible
About 30% of wildlife watchers report a California Gall Wasp sighting in Sacramento on a given day, based on 531 verified sightings from GBIF citizen-science data. It is the 7th most-seen of the 386 insects we can rate there. Over three days the chance rises to about 60%, and over a week to about 90%, if each day is a fresh chance.
September
In that month about 40% of wildlife watchers report a California Gall Wasp in Sacramento on a given day, against about 20% in June–July and October–March, the lowest months. That is one of Sacramento's driest months, with almost no rain against 120 mm in December.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most California Gall Wasp sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 6 cities where we can rate California Gall Wasp sightings, Sacramento has the highest daily chance: about 30%. Next come San Francisco (United States, about 10%) and Portland (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the California Gall Wasp is recorded against all the insects logged in Sacramento (531 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.
