Semaphore Fly

Semaphore Fly

Poecilobothrus nobilitatus

Daily sighting probability <5% · Rare
at Leeds

In 3 days ~10% in a week ~30%

5 Verified sightings at Leeds
6 In 1 park From 2019 to 2026
July Best month
🌅 Crepuscular When it's spotted

About the Semaphore Fly

Poecilobothrus nobilitatus or semaphore fly is a species of fly in the highly studied family Dolichopodidae. P. nobilitatus flies are popular study subjects because they are easy to recognize and are of large size. They mainly reside around ponds and wet lands, where most of their hunting and mating take place. Their mating ritual is highly studied due to their distinctive mate selection behaviors.

P. nobilitatus has been found in Austria, Belgium, Czech Republic, Denmark, France, Germany, Hungary, Ireland, Italy, Luxembourg, Netherlands, Poland, Romania, Russia, Slovakia, Spain, Sweden, Switzerland, and the UK. Many flies in the Dolichopodidae family have metallic green reflections in their cornea due to the cornea's wavelength-selective spectral reflectance. Their cornea is built like a multi-layered mirror that reduces the transmission of green light to the cornea's light receptors. This results in distinctive green iridescent eyes that many of the flies have.

The P. nobilitatus species exhibits sexual dimorphism; females and males have distinctive wing markings. Males are usually 7mm long and are smoky black on the distal half... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Wadden Sea National Park 🇩🇪 Germany
<5%

More parks will be added in future updates.

Cities Where Found

# City Country Daily sighting probability
1 Liverpool 🇬🇧 United Kingdom
~10%
2 Birmingham 🇬🇧 United Kingdom
~10%
3 London 🇬🇧 United Kingdom
~10%
4 Dublin 🇮🇪 Ireland
~10%
5 Manchester 🇬🇧 United Kingdom
<5%
6 Leeds 🇬🇧 United Kingdom
<5%

Before you go

What are the chances of seeing a Semaphore Fly in Leeds?

Rare

Under 5% of wildlife watchers report a Semaphore Fly sighting in Leeds on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 254th most-seen of the 284 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.

When is the best time to see a Semaphore Fly in Leeds?

July

In that month about 10% of wildlife watchers report a Semaphore Fly in Leeds on a given day, against under 5% in August to June, the lowest months.

What time of day is best to see a Semaphore Fly?

Between 2 and 5 pm

Across all the parks we cover, that three-hour window holds the most Semaphore Fly sightings with a recorded time, and about 7 in 10 of them come between 6 am and 6 pm: it is most active around dawn and dusk.

Is Leeds the best place to see a Semaphore Fly?

6th of 6

Of the 6 cities where we can rate Semaphore Fly sightings, Leeds ranks 6th at under 5%. The best odds are in Liverpool (United Kingdom, about 10%), Birmingham (United Kingdom, about 10%) and London (United Kingdom, about 10%).

Which relatives of the Semaphore Fly live in Leeds?

Same order: Diptera

The closest relatives of the Semaphore Fly that you can see in Leeds (order Diptera, Flies) are Marmalade Hover Fly (about 20%), Tapered Drone Fly (about 20%) and Sun Fly (about 20%), with each one's daily chance of a sighting.

Where does the Semaphore Fly sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Semaphore Fly is recorded against all the insects logged in Leeds (5 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.

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