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Rise of the Armed Nomads

Armed Nomad bee male at Grangelands

Last Sunday morning I was walking in the Buckinghamshire Chilterns. I was feeling a bit tired and unenthusiastic, and for once was not really thinking about recording insects. But it’s impossible to completely turn off the entomological instincts, and a fairly large cuckoo bee (or nomad bee, genus Nomada) caught my eye. It was flying among the vegetation at the top of a bank on BBOWT‘s Grangelands nature reserve.

Armed Nomad bee female at Grangelands – very fuzzy photo!

I took a quick snap but wasn’t very careful about it, and the bee soon vanished into the undergrowth. But it had looked somehow different, and as I walked home it dawned on me that it just might have been something special. By the time I got home I was keen to see the photo, but I’d done a really poor job – blurry and distant. Even so, what few details I could make out were consistent with it being something potentially very special: was there a chance it could be the Armed Nomad Bee, Nomada armata.

That, however,  is a Red Data Book 1 species, and listed as being of ‘Principal Importance’ in the NERC Act. And as far as I knew it hadn’t been seen anywhere outside Salisbury Plain for about 50 years. So a grotty blurred photo wasn’t really going to cut it.

Nomada bees are ‘cleptoparasitic’ bees that take over the nests of other bees. The host for the Armed Nomad is Andrena hattorfiana, the Large Scabious Mining Bee, itself a rare species but one that has been spreading, and was first found in Buckinghamshire in 2007, by Aaron Woods, near Beaconsfield. Following that it has been seen at a few other sites, including at Grangelands, where Ryan Clark discovered it a few years ago. So it was at least conceivable that the Armed Nomad had started to follow the expanding range of its host.

Armed Nomad bee male at Grangelands - photo 2 by Martin Harvey
Armed Nomad bee male at Grangelands showing its distinctive broad front femora

But I needed better supporting evidence! And it was getting late in the afternoon by now. So back up the hill I went. Needless to say there was no sign of the female Nomada in the original location, so I set off in search of Field Scabious flowers, which are the flower required by Andrena hattorfiana, and also visited by Nomada armata. After about an hour and a half of searching, and on the opposite side of the reserve from the morning’s sighting, I saw a bee on a Field Scabious flowers.

Armed Nomad bee male at Geangelands - photo by Martin Harvey
Armed Nomad bee male at Grangelands – note the bright orange antennae

Nervous with excitement I nearly fumbled the net, but managed to catch what turned out to be a male Armed Nomad. Some slightly better photos ensued, and as soon as I got home I sent these to Stuart Roberts of BWARS, who very promptly confirmed the identification – thanks Stuart.

As far as I know this is the first time the Armed Nomad has been seen in Buckinghamshire, and the first time for about 50 years that it had been recorded away from Salisbury Plain – or so I thought …

Armed Nomad bee, female, at Dry Sandford Pit - photo by Peter Creed
Armed Nomad bee, female, at Dry Sandford Pit (photo by Peter Creed)

I reported the find to BBOWT, who passed the message on to Peter Creed, author of A guide to finding bees in Berkshire, Buckinghamshire and Oxfordshire. To my amazement Peter got in touch to say that he had also found Nomada armata the same weekend as I did, but at another BBOWT reserve, Dry Sandford Pit in Oxfordshire (vice-county Berkshire). This is a site where it had been recorded before, back in the 1970s. The known range of Nomada armata had suddenly expanded considerably!

Large Scabious Mining Bee female at Grangelands - photo by Martin Harvey
Large Scabious Mining Bee female at Grangelands

Another trip to Grangelands a couple of days later produced good sightings of the host bee Andrena hattorfiana, and one further male Nomada armata. So it looks like it has established itself on the reserve.

It’s always encouraging to see rare species making a recovery, and while it is early days for this one the hope is that both host bee and cuckoo will continue to strengthen their populations and distribution. And BBOWT’s reserves are clearly playing an important role in allowing them to do so. It’s intriguing to think what journeys the Nomada must have made to get from Salisbury Plain to the Buckinghamshire Chilterns.

Armed Nomad bee male at Grangelands - photo 4 by Martin Harvey
Armed Nomad bee male at Grangelands

For more information on the Armed Nomad see the factsheet from Buglife (pdf). Steven Falk has more photos of Andrena hattorfiana and Nomada armata.

 

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Ragwort: what a fantastic plant for bees

Ragwort was in the news again earlier this year. I got interviewed on local radio about its value for moths (not a very rewarding experience, since the presenter seemed unable to get past his amusement at the idea of anyone actually being interested in moths). And environment minister Richard Benyon attracted a bit of attention with some ill-conceived Facebook comments about his hatred of Ragwort. Shortly after that episode, I happened upon this clump of Ragwort in full flower in the middle of one of my local SSSIs:

How many bees can you see on the flowers?

There were at least 50, which I’ve carefully highlighted in the second version of this photo, and they were having a fine old time necking nectar and perusing pollen:

On this occasion I didn’t capture any to check the species; there were several involved, but I’m pretty sure that many of them were the solitary ground-nesting bee Lasioglossum calceatum (this one, with its long antennae, looks like a male): 

Now, Ragwort can cause problems, being toxic to grazing mammals when consumed in large quantities, and where it poses a genuine risk to these animals it needs to be controlled. But in areas where grazing animals aren’t an issue, Ragwort provides a valuable resource for many, many insects, including at least 30 insects and 14 fungi that are entirely dependent on the plant, plus the huge numbers of insects that visit the flowers for pollen and nectar, as shown above.
The controversy over the rights and wrongs of ragwort has raged for years now, and the claims for its harmful effects have often been widely exaggerated. There’s plenty of good information about Ragwort available nowadays, not least in DEFRA’s own Code of Conduct, so there’s not really any excuse for continuing to demonise the plant. Like most entomologists, I remain pleased to see Ragwort in all non-grazing-mammal contexts, and hope to see many more plants covered in the buzzing of contented bees, flies, beetles and butterflies – the sheer exuberance of the bees in the photos above were one of my year’s wildlife highlights.

Good sense on Ragwort is available from:

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Identifying invertebrates: downloadable keys

The previous post listed some identification keys that run online, as more-or-less interactive websites. This post includes some sites that have keys you can download (usually as pdf documents) and print out. See also my bookmarks on delicious.

Various groups
Some excellent materials, many produced by Brian Eversham, are available on the website for The Wildlife Trust for Bedfordshire, Cambridgeshire, Northamptonshire and Peterborough [link updated at October 2012]. These include keys to insect orders, grasshoppers and bush-crickets, water bugs, ants, beetle families, longhorn beetles and soldier beetles (plus other non-insect groups). NB that most of these are tailored to the Bedfordshire area, and do not necessarily include all UK species (the exception being the soldier-beetle one by Dr Mike Fitton, which does have all species).

Lepidoptera
Various resources, including an identification guide to grass moths (Pyralidae: Crambinae) compiled by Nick Asher, can be downloaded from the Berkshire Moth Group.

Hymenoptera
Some keys to selected groups of bees and ants are available from BWARS.

Diptera
Dipterists Forum has produced some really good downloadable keyes, some of which are available only to DF members; these include a very well-illustrated key to Diptera families, a key to Scathophagidae (dung-flies and allies), both of these by Stuart Ball, and a version of Alan Stubbs key to hoverfly tribes illustrated with photos by Stuart Ball – Dipterists Forum is worth joining just for these, let alone all the other benefits!

Available to anyone is the set of draft keys to craneflies, by Alan Stubbs, and keys to stilt and stalk flies, by Darwyn Sumner.

Coleoptera
The recently established Beetle News has included keys to various small groups of beetles in its first few editions, and they can be downloaded from the Amateur Entomologists’ Society.

Field Studies Council
This listing from the FSC includes many of their published keys, available to purchase, but also some older papers that are free to download, including Unwin’s key to Diptera families, and the now slightly out-of-date key to slugs by Cameron, Eversham and Jackson.

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New atlas of bees, wasps and ants

The latest atlas in the set being published by BWARS arrived a week or two ago:
Edwards, R., and Roy, H. (eds) 2009. Provisional atlas of aculeate Hymenoptera of Britain and Ireland Part 7. Wallingford: Biological Records Centre.

Part 7 of this atlas includes maps for a further 58 species, with brief species accounts summarising the distribution, ecology and conservation status. Following the BWARS plan, part 7 contains a mix of ants, wasps and bees, including nine of the small (and hard to identify) parasitic jewel wasps in genus Chrysis, seven of the solitary wasps in genus Crossocerus, a range of solitary bees and six bumblebees (genus Bombus).

The latter group includes an account of Bombus cullumanus, last recorded in Britain in 1941, in Berkshire, and now considered extinct following recent surveys of all the sites from which it was previously known. By contrast, the map for Bombus hypnorum shows how far this species has spread since it colonised Britain in 2001.

There is a useful summary of the problems of distinguishing workers of Bombus terrestris from those of Bombus lucorum (queens and males can be separated relatively easily, although for queens the situation is becoming more difficult as colonies of the continental, white-tailed, race of Bombus terrestris have been imported for commercial use); and of the status of Bombus lucorum itself, which has been shown to be an aggregate of three very similar species: B. lucorum sensu stricto, B. magnus and B. cryptarum.

The dot maps in part 7 show the most recent records as black dots for the period 1970 to 2007 (or so it says on page 9, but I think at least some of the maps include records after 2007 – certainly that for Bombus hypnorum does). While this maintains consistency with the maps in the previous parts of the atlas, it does not enable more recent changes in distribution to be shown. For example, it would have been good to see the recent expansion of range in species such as the parasitic bee Sphecodes niger shown more clearly on the maps.

One reason for producing atlases, and one of the reasons why mambers of BWARS work so hard to collate the records, is to monitor changes in species and look out for any worrying declines, and in part 7 there several examples of just this. For instance, the closely related solitary bees Andrena rosae and A. stragulata have not previously been listed as scarce or declining, but these maps show that there is cause for concern with few recent records.

The BWARS data for these species (but not the species accounts) can be seen on the NBN Gateway – for example, here is the map for Specodes niger.