Istocheta aldrichi
In 3 days ~20% in a week ~40%
Istocheta aldrichi or winsome fly is a species of fly in the family Tachinidae. Originally from Japan, it has been introduced in North America in 1922 as a biocontrol to combat the Japanese beetle (Popillia japonica). It is established in northeastern North America, including Canada and the USA. Larvae pupate inside the host beetle after hatching from an egg laid on the beetle's pronotum. Historical host range catalogues and recently collected crowdsourced data suggests that this fly is highly specific to Japanese beetle and probably does not attack other beetle species. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Acadia National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Montreal | 🇨🇦 Canada | |
| 2 | Minneapolis [Saint Paul] | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Winsome Fly sighting in Montreal on a given day, based on 163 verified sightings from GBIF citizen-science data. It is the 94th most-seen of the 926 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
July
In that month about 20% of wildlife watchers report a Winsome Fly in Montreal on a given day, against under 5% in August to June, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Winsome Fly sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 2 cities where we can rate Winsome Fly sightings, Montreal has the highest daily chance: about 10%. Next come Minneapolis [Saint Paul] (United States, about 10%).
GBIF citizen-science records
It is estimated from how often the Winsome Fly is recorded against all the insects logged in Montreal (163 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.
