Cassida rubiginosa
In 3 days ~10% in a week ~20%
The thistle tortoise beetle (Cassida rubiginosa) is a species of beetle in the subfamily Cassidinae (tortoise beetles) and the genus Cassida. The thistle tortoise beetle can be recognized by its green, rounded back and it can be found on thistle plants in many regions of North America and Europe. The thistle tortoise beetle was first discovered in 1902 in Lévis, Quebec. In 1931, Nellie F. Paterson was the first to document the mature larva. Later, the instar larva of this species was first recorded in 2004 by Jolanta Świętojańska. The thistle tortoise beetle exhibits multiple defense behaviors, such as a flexible shield, providing a barrier against the mandibles of predators, and an excretion that protects the eggs as well.
Its ability to massively consume and damage thistle plants has also made this beetle a well known biological control agent in many countries, including the United States, Canada, and Switzerland. However, in some cases, the impact of these beetles has been limited due to parasitism preventing their accumulation in regions of thistle targeted for biological control.
The thistle tortioise beetles measure 6.0–8.0 mm in length. Like all Cassida, its... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Elk Island National Park | 🇨🇦 Canada | |
| 2 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 3 | Shenandoah National Park | 🇺🇸 United States | |
| 4 | Wadden Sea National Park | 🇩🇪 Germany | |
| 5 | Pyrénées National Park | 🇫🇷 France |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Birmingham | 🇬🇧 United Kingdom | |
| 2 | Rotterdam [The Hague] | 🇳🇱 Netherlands | |
| 3 | Manchester | 🇬🇧 United Kingdom | |
| 4 | Bucharest | 🇷🇴 Romania | |
| 5 | London | 🇬🇧 United Kingdom | |
| 6 | Helsinki | 🇫🇮 Finland | |
| 7 | Liverpool | 🇬🇧 United Kingdom | |
| 8 | Kyiv | 🇺🇦 Ukraine | |
| 9 | Edmonton | 🇨🇦 Canada | |
| 10 | Toronto | 🇨🇦 Canada |
Rare
Under 5% of wildlife watchers report a Thistle Tortoise Beetle sighting in Toronto on a given day, based on 68 verified sightings from GBIF citizen-science data. It is the 314th most-seen of the 1689 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.
May and June
In those months about 10% of wildlife watchers report a Thistle Tortoise Beetle in Toronto on a given day, against under 5% in July to April, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Thistle Tortoise Beetle sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
10th of 20
Of the 20 cities where we can rate Thistle Tortoise Beetle sightings, Toronto ranks 10th at under 5%. The best odds are in Birmingham (United Kingdom, about 10%), Rotterdam [The Hague] (Netherlands, about 10%) and Manchester (United Kingdom, about 10%).
GBIF citizen-science records
It is estimated from how often the Thistle Tortoise Beetle is recorded against all the insects logged in Toronto (68 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.
