Species of the Month - May 2017

Dark-edged Bee-fly

Bombylius major

Bombylius major

This is the only Bee-fly species hardy enough to live in our part of the country, so we simply call it the Bee-fly, but it is actually one of nine British species.  It can be told from the others by the wing pattern, with a sharp division between the dark leading half and the clear trailing half, hence its full name is the Dark-edged Bee-fly.

This wing pattern is hard to see, as an active Bee-fly keeps its wings whirring all the time, whether hovering beside a flower to extract nectar or standing on the petals for a better grip.  But it can be safely identified from its size (8-10 mm long), behaviour, extremely long proboscis, and bumblebee-like appearance.

It takes great patience to get a photo as good as that by Caroline Anderson above, showing the wing markings clearly while the insect is at rest.

Bombylius major

This is a more typical view, with whirring wings, and proboscis like an extra leg.  The photo was taken on 25 March, our earliest Bee-fly on record.  Most of our records are in May with a few in April.

Bombylius major

This photo by Jan Hamilton shows the Bee-fly on one of its favourite nectar sources, the Cuckoo Flower.  It is also fond of Daisies, Dandelions, Primroses and many other spring flowers.  In gardens it enjoys visiting Drumstick Primulas.

Bombylius major

According to Stubbs and Drake (British Soldierflies and their Allies, 2001), the Dark-edged Bee-fly "cannot fly when the temperature is less than about 17C"  Here in Argyll they fly at much lower temperatures than that, provided the sun is shining.

Bombylius major

Bee-flies scatter their eggs on the ground in places where solitary bees or wasps are likely to make their burrows.  This strategy seems just as effective as that of other Bee-fly species that deliberately target existing burrows, which presumably brings a higher success rate per egg but costs time and energy to do.  When the Bee-fly larva emerges it looks around for a burrow and if it is very lucky it finds one within range, whereupon it crawls inside and feeds on the solitary bee or wasp's larva.

Solitary bees and wasps are not particularly common in our area, compared to places further south or east with drier soils, and the Bee-fly's random method of egg-laying may seem hopelessly optimistic, but it obviously works as the Bee-fly population here is thriving.

Bombylius major

There is still a lot to be discovered about the lifestyle of the Bee-fly, particularly in our area where it may be different from elsewhere, as evidenced by its tolerance of lower temperatures here.  Any observations of Bee-flies will be of great interest, including flowers visited, weather conditions, courtship and mating behaviour and particularly the places where eggs are laid, if you are lucky enough to see this happen, and notes on any solitary bees or wasps that nest in the place where the Bee-fly eggs were laid.

Please send in your Bee-fly sightings using the form below, or email sightings@lnhg.org.uk with the details if you prefer.  If you are not sure of the identity of your insect, please send a photo to sightings@lnhg.org.uk, or put one on the LNHG Facebook page.

Date of sighting 
Grid reference 
Flowers visited  
Name of finder 
Your name (if different) 
Email (not needed if I already know it!) 
Any other details, e.g numbers, habitat,
 weather conditions, behaviour


By filling in this form you agree that the information contained in this form may be collated and disseminated manually or electronically for environmental decision-making, education, research and other public benefit uses in accordance with the LNHG data access policy.  Your email address will not form part of the record and will not be passed on to anyone.

Carl Farmer
LNHG Biological Records Manager


Note you can still send in records for past species of the month.  Here are the previous May species:

May 2016 - Common Heath
May 2015 - Orange Tip
May 2014 - Large Red Damselfly
May 2013 - Early Purple Orchid
May 2012 - Small Copper
May 2011 - Green Hairstreak

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This project is supported by Scottish Natural Heritage

All photos and other content copyright Carl Farmer except where stated.  First photo is Caroline Anderson and third is Jan Hamilton.  Mouse over photos to see credits.