The Highland Biological Recording Group

The Bee-fly Bombylius major: Report, July 2010 Jimmy McKellar

The Beefly Bombylius major. Left: in typical posture, basking in the spring sun on semi-bare ground. Right: hovering at a flower 'humming-bird style' showing the characteristic long proboscis. The brown hairy body, patterned wings held in a 'V' shape, and the long proboscis are sure identification features.. Photos © Jane Bowman.
This project has run from 1999 to 2010, a 12 year stretch over which time we have amassed a very respectable number of records and greatly increased the known distribution of this interesting little fly in both Highland and Scotland. As the original benchmark showed only a few records (8) any extra dots on our map were certain to represent an expansion to the known distribution. However we need to realise that this species, for a number of reasons, may well have been under recorded in the past and very probably remains under recorded today. Hence the extra dots may in essence only reflect a more accurate and truer distribution, rather than any real expansion of range. Some reasons for possible under recording of these flies are that they are on the wing early in the year, flying in Highland from around the 1st of April to early June annually. This is out-with the normal holiday season for recorders and the weather is often rather cold for biological recording activity. It is also a relatively short window of opportunity coupled with the fact that they are seldom common and tend to fly rapidly and are quite cryptic when settled. This all adds to the likelihood of under recording and of course the small number of recorders who can reliably recognise this species is also a limiting factor which narrows the distribution of records to the areas where these recorders live, or visit, and restricts the number of records submitted. Despite the difficulties of finding and identifying these flies, learning to do so is relatively easy once you have a few facts to hand. Bee-flies (Bombyliidae) have stout, furry bodies, are true flies (Order: Diptera) and belong in the suborder Brachycera and as their furry appearance makes them look a little like bumblebees that is how they get their name. Bee-flies are harmless to humans but are parasitic on the larva of solitary bees. As adults they feed on nectar and use their long proboscis to sip it whilst hovering in front of flowers. They do this by resting their front feet on the petals presumably for balance. Bee-flies are very agile and often hover near flowers before darting quickly away and then returning to hover again a short time later.
Distribution of Bombylius major in Scotland (10km square resolution) from the NBN Gateway. The National Biodiversity Network records are shown on the map (see terms and conditions). Data providers (list and interactive map ) and the NBN Trust bear no responsibility for any further analysis or interpretation of the information in the map.	Stubbs & Drake (2001) state that 'females have been seen apparently laying eggs on woodland soil even in the absence of host burrows, as if speculatively laying where hosts may come to live'. They go on to explain that females 'have a special sand chamber (a modification of sternites 8 and 9) with associated lateral spines'. It now seems to be accepted that 'eggs are flicked out one at a time using the ovipositor spines whilst the fly is hovering'. Further, the mechanism used to gather the dust or sand is by settling on the earth in direct contact with the ground to fill the chamber. The first-instar larva is a planidium which is unlike the later instars and actively seeks out its host. From the records we have built up we can state that they like sun-traps in sheltered locations or south facing banks, they seem to prefer dry slopes with bare soil and a variety of flowers to nectar at including dandelion, primrose, green alkanet and other spring flowers. Unsurprisingly these are just the conditions the solitary bees like. This sun-loving insect only flies when the sun shines and anecdotal evidence suggests that even very short periods of sunshine are enough to bring them out. These flies always appear to face uphill when they land on a slope and I have yet to see one land facing any other direction.
Phenology: The chart on the right represents the relative abundance of individuals in each quarter of the months we have records for. Strangely there were no March records. The chart clearly shows the marked reduction from mid-May, and gives us a fairly good idea of the best times to search. As can be seen from the map above,we now have records from almost all the original areas and expanded the distribution as predicted. It was very pleasing to get so many records from around the country and I would like to thank everyone who sent them so that this species could quite literally be put on the map.	If the graph does not load, please install or enable javascript ... Chart drawn with JS Charts.
Records of Beeflies may be sent to: . Specimens of solitary bees associated with them - contact Murdo Macdonald . All the usual information, please. Time of day, weather and behaviour will also be useful. Previous bee-fly articles in the Highland Biological Recording Group Newsletters may be of interest: McKellar J. (1999) Bee-Fly Bombylius major. HBRG Newsletter 12: 14-15. McKellar J. (2000) The Bee-Fly Bombylius major. HBRG Newsletter 13: 5-6. McKellar J. (2001) The Bee-Fly Bombylius major. HBRG Newsletter 14: 14-16. McKellar J. (2002) The Beefly Bombylius major. HBRG Newsletter 15: 22-23. McKellar J. (2003) Beefly Bombylius major. HBRG Newsletter 16: 9-10. McKellar J. (2004) The Beefly Bombylius major. HBRG Newsletter 17: 7-8. McKellar J. (2005) The Beefly Bombylius major. HBRG The Highland Naturalist 1: 13 McKellar J. (2006) The Beefly Bombylius major. HBRG The Highland Naturalist 2: 34 McKellar J. (2007) The Beefly Bombylius major. HBRG The Highland Naturalist 3: 31-32 Reference: Stubbs, A.E. & Drake, M. (2001) British soldierflies and their allies. BENHS, London, 512 pp.