Species of the Month: June 2025

Semaphore Fly Poecilobothrus nobilitatus

June is a great time to spot this attractive fly, which is distinctive enough to easily record (unusually for a fly species), but remains under represented in the SEWBReC database.

Male Semaphore Flies are notable for their bright white wing tips, contrasting with the dark upper wings and metallic green bodies. (We do not recommend attempting to identify the females unless you happen to be an experienced dipterist, as these resemble many other species in the genus.)  Poecilobothrus nobilitatus prefers damp habitats, and can often be found on the surface or around the muddy edges of puddles and ponds. They will also sit on nearby vegetation, where their distinctive wingtips stand out (see photo below). You may also be lucky enough to witness their courtship ritual, with the males performing acrobatic flights over a chosen female. 

Despite this distinctive species being common and widespread in suitable habitats, we only have less than 500 records for the SEWBReC area; view a 1km distribution map here.

You can find more image and information about of Semaphore Fly on Naturespot and BBC Wildlife (the latter particularly expands on their courtship ritual). You can view Wales-wide distribution map here.

If you spot Poecilobothrus nobilitatus during June (or at any other time of year) please send us the record, ideally via SEWBReCORD or the LERC Wales App. Instructions on how to submit records are available here.