Isodontia mexicana
In 3 days ~10% in a week ~20%
Isodontia mexicana, the Mexican grass-carrying wasp, is a species of insect belonging to the family Sphecidae. It is mainly found throughout North America, but has become established in Europe, primarily France, Switzerland, Hungary, Italy, Serbia, and Spain.
The adults grow up to 18–20 millimetres (0.71–0.79 in) long, the body is completely black, the thorax is quite hairy and the wings have a smoky-brown color. They can be encountered from early summer through September. Females are larger and emerge as adults later in the season than males.
Isodontia mexicana is a typical case of a species arrived accidentally from North America and slowly encroaching on the European continent, probably for the lack of predators or parasites. These wasps build their nests in hollowed branches or in other natural cavities, often reusing the nests of other species. Then they line the inside with grass fragments or other plant fibers (hence the name of 'grass-carrying wasps').
Isodontia mexicana mainly preys on grasshoppers (usually katydids, Tettigoniidae species) or tree crickets (Gryllidae species), choosing the small ones and carrying them to its nest to feed the emerging larvae with the living, but paralyzed Orthoptera. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 2 | Cévennes National Park | 🇫🇷 France | |
| 3 | Pyrénées National Park | 🇫🇷 France |
Rare
Under 5% of wildlife watchers report a Mexican Grass-Carrying Wasp sighting in Pyrénées National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 1144th most-seen of the 1277 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
June
In that month about 10% of wildlife watchers report a Mexican Grass-Carrying Wasp in Pyrénées National Park on a given day, against under 5% in July to May, the lowest months.
Between 3 and 6 pm
Across all the parks we cover, that three-hour window holds the most Mexican Grass-Carrying Wasp sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 3
Of the 3 parks where we can rate Mexican Grass-Carrying Wasp sightings, Pyrénées National Park ranks 3rd at under 5%. The best odds are in Bavarian Forest National Park (Germany, about 10%) and Cévennes National Park (France, under 5%).
GBIF citizen-science records
It is estimated from how often the Mexican Grass-Carrying Wasp is recorded against all the insects logged in Pyrénées National Park (5 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.
