Anasimyia bilinearis
In 3 days ~10% in a week ~20%
Anasimyia bilinearis, the two-lined swamp fly, is an uncommon species of syrphid fly observed throughout North America. Hoverflies can remain nearly motionless in flight. The adults are also known as flower flies for they are commonly found on flowers from which they get both energy-giving nectar and protein-rich pollen. Larvae of this genus are of the rat-tailed type living in aquatic environments. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Two-Lined Swamp Fly sighting in Boston on a given day, based on 12 verified sightings from GBIF citizen-science data. It is the 695th most-seen of the 1200 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
In that month about 10% of wildlife watchers report a Two-Lined Swamp Fly in Boston on a given day, against under 5% in June to April, the lowest months.
Yes
Of the 2 cities where we can rate Two-Lined Swamp Fly sightings, Boston has the highest daily chance: under 5%. Next come Toronto (Canada, under 5%).
Same family: Syrphidae
The closest relatives of the Two-Lined Swamp Fly that you can see in Boston (family Syrphidae, Hover Flies) are Margined Calligrapher (about 20%), Eastern Calligrapher (about 20%) and Transverse-Banded Flower Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Two-Lined Swamp Fly is recorded against all the insects logged in Boston (12 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.
