Pterostichus melanarius
In 3 days ~10% in a week ~20%
Pterostichus melanarius, the rain beetle, is a type of carabid (ground beetle) of the genus Pterostichus. It is native to Europe but is increasingly found in North America after being introduced to the region in the 1920s. It is a predatory beetle that eats other invertebrates, which makes it a valuable pest control agent in agricultural settings. Additionally, the beetle has wing dimorphism which has contributed to its increasing distribution across North America.
The larvae of this species of beetle have been observed exhibiting cannibalistic behaviorisms in high population densities. The rain beetle's habitat is influenced by their hunger level, with starved beetles preferring larger prey ranges compared to satiated beetles.
Adults of P. melanarius grow to be 12–18mm long. They appear black with straight striations on their elytra. They "are distinguished from other Pterostichus species by their laterobasal carina and denticulate posterior angles of the pronotum." Adults have wing dimorphism, characterized by brachypterous beetles and macropterous beetles. Brachypterous beetles have shortened hind wings and are unable to fly. Macropterous beetles have mature hind... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Elk Island National Park | 🇨🇦 Canada | |
| 2 | Riding Mountain National Park | 🇨🇦 Canada |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Anchorage | 🇺🇸 United States | |
| 2 | Calgary | 🇨🇦 Canada | |
| 3 | Edmonton | 🇨🇦 Canada | |
| 4 | Kyiv | 🇺🇦 Ukraine | |
| 5 | Nizhny Novgorod | 🇷🇺 Russia | |
| 6 | Vancouver | 🇨🇦 Canada | |
| 7 | Yekaterinburg | 🇷🇺 Russia | |
| 8 | Salt Lake City | 🇺🇸 United States | |
| 9 | Seattle | 🇺🇸 United States | |
| 10 | Moscow | 🇷🇺 Russia |
Rare
Under 5% of wildlife watchers report a Rain Beetle sighting in Denver on a given day, based on 6 verified sightings from GBIF citizen-science data. It is the 384th 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.
October
In that month about 10% of wildlife watchers report a Rain Beetle in Denver on a given day, against under 5% in November to September, the lowest months.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Rain Beetle sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is seen both by day and at night.
13th of 16
Of the 16 cities where we can rate Rain Beetle sightings, Denver ranks 13th at under 5%. The best odds are in Anchorage (United States, about 20%), Calgary (Canada, about 10%) and Edmonton (Canada, about 10%).
Same family: Carabidae
The closest relatives of the Rain Beetle that you can see in Denver (family Carabidae, Ground Beetles) are Punctured Tiger Beetle (about 10%) and Bronzed Tiger Beetle (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Rain Beetle is recorded against all the insects logged in Denver (6 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.
