Boisea rubrolineata
In 3 days ~20% in a week ~40%
Boisea rubrolineata or the western boxelder bug is identical to the eastern boxelder bug aside from having prominent red veins on its corium. It is found in western North America. Adults are 9–13 mm in length. The thorax and wings are black with red lines, and the abdomen is red. Nymphs are bright red and gray. Both nymphs and adults feed on boxelder. In fall and winter, adults might be noted migrating indoors to hibernate. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Yosemite National Park | 🇺🇸 United States | |
| 2 | Sequoia and Kings Canyon National Parks | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Portland | 🇺🇸 United States | |
| 2 | Sacramento | 🇺🇸 United States | |
| 3 | San Francisco | 🇺🇸 United States | |
| 4 | Seattle | 🇺🇸 United States | |
| 5 | Los Angeles | 🇺🇸 United States | |
| 6 | San Diego | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Western Boxelder Bug sighting in Sequoia and Kings Canyon National Parks on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 137th most-seen of the 161 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
December to February
In those months about 30% of wildlife watchers report a Western Boxelder Bug in Sequoia and Kings Canyon National Parks on a given day, against under 5% in April and June–November, the lowest months. Those are among Sequoia and Kings Canyon National Parks's wettest months, with about 150 mm of rain a month against 10 mm in September.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Western Boxelder Bug 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 parks where we can rate Western Boxelder Bug sightings, Sequoia and Kings Canyon National Parks ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Yosemite National Park (United States, about 10%).
Same order: Hemiptera
The closest relatives of the Western Boxelder Bug that you can see in Sequoia and Kings Canyon National Parks (order Hemiptera, True Bugs, Hoppers, Aphids, and allies) are North American Common Water Strider (about 10%), Manzanita Leafgall Aphid (about 10%) and Hedge Nettle Stink Bug (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Boxelder Bug is recorded against all the insects logged in Sequoia and Kings Canyon National Parks (7 verified sightings from 2019 to 2026), 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.
