Chrysolina coerulans
In 3 days ~20% in a week ~30%
Chrysolina coerulans, also known as the blue mint beetle or blue mint leaf beetle, is a species of beetle in the family Chrysomelidae. It is a member of the subgenus Synerga of the genus Chrysolina. It is native to a wide range of countries between Central and Eastern Europe and lives alongside rivers and in meadows, it feeds on various plant members of the mint family.
It was first spotted in the UK in 2011, when it was first reported to the Royal Horticultural Society's entomology department in July. In 2012, it was found breeding in Kent, Cambridgeshire and Lincolnshire. It has further spread throughout the UK.
The larvae of Chrysolina coerulans are soft-bodied, rounded in shape and black in colour. Th adult beetles are 6–10 mm (0.24–0.39 in) long, with black legs and antennae. It has a smooth head, without longitudinal groove, and parallel-sided thorax. The pronotal disk (which is found at the top of the first thoracic segment) of C. coerulans has fine punctures.
It has a smooth elytra (hardened forewing), which is distinctly metallic blue, or iridescent blue. These beetles should not be confused with the 'green mint beetle' (or Chrysolina herbacea), as it is... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Wadden Sea National Park | 🇩🇪 Germany |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Rotterdam [The Hague] | 🇳🇱 Netherlands | |
| 2 | Amsterdam | 🇳🇱 Netherlands | |
| 3 | Essen | 🇩🇪 Germany | |
| 4 | Prague | 🇨🇿 Czechia |
With luck
About 10% of wildlife watchers report a Mint Beetle sighting in Amsterdam on a given day, based on 7 verified sightings from GBIF citizen-science data. It is the 151st most-seen of the 234 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
February, April–May and July–October
In those months about 10% of wildlife watchers report a Mint Beetle in Amsterdam on a given day, against under 5% in March, June and November–January, the lowest months.
Between 5 and 8 pm
Across all the parks we cover, that three-hour window holds the most Mint Beetle sightings with a recorded time, and about 6 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.
Among the best
Of the 4 cities where we can rate Mint Beetle sightings, Amsterdam ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Rotterdam [The Hague] (Netherlands, about 10%).
GBIF citizen-science records
It is estimated from how often the Mint Beetle is recorded against all the insects logged in Amsterdam (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.
