Rasahus thoracicus
In 3 days ~20% in a week ~30%
The western corsair (Rasahus thoracicus) is a species of assassin bug and is one of the two species of "two spotted corsairs", the other being Rasahus biguttatus. The adults have an orange and black body and an orange spot on each wing. They feed primarily on other insects and after dark are attracted to bright lights (where prey are ample). The bite of the western corsair can be extremely painful. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Big Bend National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Sacramento | 🇺🇸 United States | |
| 2 | Los Angeles | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Western Corsair Bug sighting in Big Bend National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 221st most-seen of the 329 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
January
In that month about 20% of wildlife watchers report a Western Corsair Bug in Big Bend National Park on a given day, against under 5% in February, May–September and December, the lowest months. That is one of Big Bend National Park's driest months, with about 10 mm of rain against 50 mm in September.
Between 7 and 10 pm
Across all the parks we cover, that three-hour window holds the most Western Corsair Bug sightings with a recorded time, and nearly all of them come between 6 pm and 6 am: it is mostly seen at night.
Only Big Bend National Park, in our data
Big Bend National Park is the only park on Wallace's Line with enough records to rate Western Corsair Bug sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Reduviidae
The closest relatives of the Western Corsair Bug that you can see in Big Bend National Park (family Reduviidae, Assassin Bugs) are Triatoma gerstaeckeri (about 10%) and Triatoma rubida (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Western Corsair Bug is recorded against all the insects logged in Big Bend National Park (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.
