Thasus neocalifornicus
In 3 days ~20% in a week ~40%
The giant mesquite bug (Thasus neocalifornicus) is an insect of the order Hemiptera, or the "true bugs". As a member of the family Coreidae, it is a leaf-footed bug. As the common name implies, it is a large bug that feeds on mesquite trees of the American Southwest and Northwestern Mexico.
Thasus neocalifornicus is univoltine, meaning they have one generation of offspring annually. From January through July, the nymphs develop from first-fifth instars. Each subsequent instar more closely resembles an adult than the last. They often prefer the undersides of leaves and migrate towards the base of mesquite trees in summer. Adults lay eggs on the trees from August until October. Only the eggs survive the winter season.
Thasus neocalifornicus inhabits the Sonoran Desert from southwestern Arizona to the Mexican state of Baja California Sur and can be plentiful depending on the season. They have also been found in the state of Texas and the Mexican states of Sinaloa and Sonora. Most populations in the United States occur in the Tucson area, and around the southern tip of Baja California Sur in Mexico. It is the only species in the genus Thasus known to... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Saguaro National Park | 🇺🇸 United States |
More parks will be added in future updates.
With luck
About 10% of wildlife watchers report a Giant Mesquite Bug sighting in Saguaro National Park on a given day, based on 25 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 100th most-seen of the 354 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.
June
In that month about 20% of wildlife watchers report a Giant Mesquite Bug in Saguaro National Park on a given day, against under 5% in October to May, the lowest months. That is one of Saguaro National Park's driest months, with about 10 mm of rain against 55 mm in July.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Giant Mesquite Bug sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Saguaro National Park, in our data
Saguaro National Park is the only park on Wallace's Line with enough records to rate Giant Mesquite Bug sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Coreidae
The closest relatives of the Giant Mesquite Bug that you can see in Saguaro National Park (family Coreidae, Leaf-footed Bugs) are Cactus Coreid Bug (about 10%), Leaf-Footed Cactus Bug (about 10%) and Giant Agave Bug (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Giant Mesquite Bug is recorded against all the insects logged in Saguaro National Park (25 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.
