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 Chicago on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 637th most-seen of the 978 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.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Mexican Grass-Carrying Wasp in Chicago on a given day, so our monthly data shows no clear season.
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.
26th of 26
Of the 26 cities where we can rate Mexican Grass-Carrying Wasp sightings, Chicago ranks 26th at under 5%. The best odds are in Warsaw (Poland, about 10%), Berlin (Germany, about 10%) and Paris (France, about 10%).
GBIF citizen-science records
It is estimated from how often the Mexican Grass-Carrying Wasp is recorded against all the insects logged in Chicago (10 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.
