Leptotes cassius
In 3 days ~70% in a week >90%
Leptotes cassius, the Cassius blue or tropical striped blue, is a butterfly of the family Lycaenidae. It is found in North America in Florida including the Keys, Texas south through the Caribbean, Mexico, and Central America to South America. Strays have been found in New Mexico, Kansas, Missouri, South Carolina, North Carolina and Virginia.
The wingspan is 20–35 mm. The butterfly species has an important role in Marisha Pessl's 2006 novel Special Topics in Calamity Physics. The protagonist, Blue van Meer, is named in honor of the Cassius blue. The caterpillars feed natively on Fabaceae. Food plants on record are Amorpha crenulata, woolly rattlepod (Crotalaria incana), Galactia regularis and lima bean (Phaseolus lunatus). It can also successfully develop feeding on Cape leadwort (Plumbago auriculata) or doctorbush (P. scandens), which (among the eudicots) are not closely related to its usual food plants. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Blue and John Crow Mountains National Park | 🇯🇲 Jamaica | |
| 2 | Everglades National Park | 🇺🇸 United States | |
| 3 | Iguazú National Park | 🇦🇷 Argentina | |
| 4 | Big Cypress National Preserve | 🇺🇸 United States | |
| 5 | Ría Lagartos Biosphere Reserve | 🇲🇽 Mexico | |
| 6 | Iguaçu National Park | 🇧🇷 Brazil | |
| 7 | Merritt Island National Wildlife Refuge | 🇺🇸 United States | |
| 8 | Cumbres de Monterrey National Park | 🇲🇽 Mexico |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Mendoza | 🇦🇷 Argentina | |
| 2 | Porto Alegre | 🇧🇷 Brazil | |
| 3 | São Paulo | 🇧🇷 Brazil | |
| 4 | Buenos Aires | 🇦🇷 Argentina | |
| 5 | Curitiba | 🇧🇷 Brazil | |
| 6 | Rosario | 🇦🇷 Argentina | |
| 7 | Caracas | 🇻🇪 Venezuela | |
| 8 | Miami | 🇺🇸 United States | |
| 9 | Cordoba | 🇦🇷 Argentina | |
| 10 | Vitória | 🇧🇷 Brazil |
Likely
About 40% of wildlife watchers report a Cassius Blue sighting in Blue and John Crow Mountains National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 6th most-seen of the 11 insects we can rate there. Over three days the chance rises to about 70%, and over a week to over 90%, if each day is a fresh chance.
February
In that month about 60% of wildlife watchers report a Cassius Blue in Blue and John Crow Mountains National Park on a given day, against under 5% in January, the lowest month.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Cassius Blue sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 8 parks where we can rate Cassius Blue sightings, Blue and John Crow Mountains National Park has the highest daily chance: about 40%. Next come Everglades National Park (United States, about 20%) and Iguazú National Park (Argentina, about 10%).
Same order: Lepidoptera
The closest relatives of the Cassius Blue that you can see in Blue and John Crow Mountains National Park (order Lepidoptera, Butterflies and Moths) are Jamaican Satyr (about 50%), Horama grotei (about 50%) and Hypercompe nigriplaga (about 50%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Cassius Blue is recorded against all the insects logged in Blue and John Crow Mountains National Park (6 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.
