Chalcosyrphus nemorum
In 3 days ~10% in a week ~20%
Chalcosyrphus (Xylotomima) nemorum (Fabricius 1805), the Dusky-banded Leafwalker, is a common species of syrphid fly with a Palearctic and Nearctic distribution. Hoverflies get their names from the ability to remain nearly motionless while in flight. The adults are also known as flower flies for they are commonly found around and on flowers, from which they get both energy-giving nectar and protein-rich pollen. Larvae have been found under the bark of Larix, Pinus and a variety of hardwoods.
External images For terms see Morphology of Diptera Wing length 6.5-8.25 mm. Hind femora are swollen and deep. Hind tibiae strongly curved and the ventral surface with closely-set short black hairs for the whole length. The abdomen is short tergites 2-4 with a pair of pink or orange-brown marks. The legs are black with yellow knees and yellow tarsi.
The larva is figured by Hartley (1961). Fennoscandia South to the Pyrenees and from Ireland East through Northern, Central and Southern Europe (to South Italy) across the Palearctic into Russia and the Russian Far East and Sakhalin and Japan. In the Nearctic from Alaska to Nova Scotia and South to California.... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Dusky-Banded Leafwalker sighting in London on a given day, based on 19 verified sightings from GBIF citizen-science data. It is the 795th most-seen of the 1504 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 Dusky-Banded Leafwalker in London on a given day, against under 5% in June to April, the lowest months.
Among the best
Of the 4 cities where we can rate Dusky-Banded Leafwalker sightings, London ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Essen (Germany, under 5%).
Same family: Syrphidae
The closest relatives of the Dusky-Banded Leafwalker that you can see in London (family Syrphidae, Hover Flies) are Yellow-Haired Sun Fly (about 40%), Marmalade Hover Fly (about 30%) and Hornet Mimic Hover Fly (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Dusky-Banded Leafwalker is recorded against all the insects logged in London (19 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.
