Argus Tortoise Beetle

Argus Tortoise Beetle

Chelymorpha cassidea

Daily sighting probability <5% · Rare
at Denver

In 3 days ~10% in a week ~20%

7 Verified sightings at Denver
14 In all 2 parks From 2019 to 2026
June Best month
☀️ Diurnal When it's spotted

About the Argus Tortoise Beetle

Chelymorpha cassidea, known generally as the Argus tortoise beetle or milkweed tortoise beetle, is a species of leaf beetle in the family Chrysomelidae. It is found in the Caribbean and North America. The beetle is 9 to 12 mm (0.35 to 0.47 in) long and is yellow to bright red with black spots. It is one of the largest leaf beetles native to North America. The name Argus comes from the mythical Greek giant Argus Panoptes, who was sometimes depicted with 100 eyes, because the beetle is able to stretch out its red head beyond its pronotum, as if it were a single red eye. The species resembles a small turtle and is similar to a ladybug.

The Argus tortoise beetle lays eggs on leaves, in clusters of 15 to 30. The eggs hatch within 10 days. Its larvae are yellowish-green or orange-yellow. The larvae feed on leaves until they are fully grown, then they drop to the soil to pupate, overwintering as pupae before emerging as adults in the middle of summer. It takes them almost three weeks to become pupae.

The beetle can be found throughout North America in meadows and roadsides. It can also be found in the Caribbean. It feeds... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Badlands National Park 🇺🇸 United States
~10%
2 Big Cypress National Preserve 🇺🇸 United States
~10%

Cities Where Found

# City Country Daily sighting probability
1 Houston 🇺🇸 United States
<5%
2 Denver 🇺🇸 United States
<5%
3 Chicago 🇺🇸 United States
<5%
4 Minneapolis [Saint Paul] 🇺🇸 United States
<5%
5 Washington 🇺🇸 United States
<5%
6 New York City 🇺🇸 United States
<5%

Before you go

What are the chances of seeing an Argus Tortoise Beetle in Denver?

Rare

Under 5% of wildlife watchers report an Argus Tortoise Beetle sighting in Denver on a given day, based on 7 verified sightings from GBIF citizen-science data. It is the 352nd most-seen of the 461 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.

When is the best time to see an Argus Tortoise Beetle in Denver?

Any time of year

In every month with enough records, under 5% of wildlife watchers report an Argus Tortoise Beetle in Denver on a given day, so our monthly data shows no clear season.

What time of day is best to see an Argus Tortoise Beetle?

Between 10 am and 1 pm

Across all the parks we cover, that three-hour window holds the most Argus Tortoise Beetle sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.

Is Denver the best place to see an Argus Tortoise Beetle?

Among the best

Of the 6 cities where we can rate Argus Tortoise Beetle sightings, Denver ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Houston (United States, under 5%).

Which relatives of the Argus Tortoise Beetle live in Denver?

Same family: Chrysomelidae

The closest relatives of the Argus Tortoise Beetle that you can see in Denver (family Chrysomelidae, Leaf Beetles) are Elm Leaf Beetle (about 10%), Spotted Cucumber Beetle (about 10%) and Rabbitbrush Beetle (about 10%), with each one's daily chance of a sighting.

Where does the Argus Tortoise Beetle sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Argus Tortoise Beetle is recorded against all the insects logged in Denver (7 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.

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