In winter 2017-18 some young Ash trees were felled at Holtspur Bottom Butterfly Conservation reserve, to open up and restore an area to chalk grassland. Logs from this felling were stacked. Last weekend we returned to clear another area, and had to move some of the logs from the previous winter.
In the intervening year rather a lot of beautiful patterns had been sculpted onto the logs, the handiwork of the Ash Bark Beetle Hylesinus varius. The females excavate an initial ‘vestibule’ in the bark, in which they mate with the males, and then bore two long egg galleries in opposite directions from the vestibule, under the bark, laying eggs at intervals along them. On hatching, the larvae start to bore another set of galleries at 90° to the egg gallery, gradually expanding the gallery width as the larvae grow. They pupate in a cell at the end of the larval gallery, from which the next generation of adult beetles emerges and bores an exit hole through the bark to fly off and find a suitable Ash log for the next generation.
The Ash Bark Beetle only enters the bark once the tree is already dead or dying, and is not believed to spread fungal diseases, so to me this is a harmless and fascinating aspect of biodiversity. As with many insects, the beetles are quickly followed by a range of parasitic wasps, and a study in the Czech Republic found that over half of the Ash Bark Beetle population in their study area succumbed to the parasitoids (Nakládal and Turčáni 2007). So there is a whole chain of life going on under the bark of the dead wood! It’s good to know that a by-product of the conservation work we carry out to benefit the grassland plants and butterflies provides habitat for these tiny but fascinating creatures.
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.
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.
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.
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 …
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!
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.
Maybe it’s the time of year: during the next few weeks Buckinghamshire is bursting with meetings, conferences and general sociability for anyone interested in recording and conserving wildlife in the county.
First up is the spring indoor meeting for the Buckinghamshire Invertebrate Group, on Saturday 14 March, 10am to 1pm, at Wendover. Anyone with an interest in insects and other invertebrates in Bucks is welcome to join the (free) mailing list for the group, which produces an excellent annual Bulletin and organises a range of field and indoor meetings. This year is BIG’s 25th anniversary, which will be celebrated at the Recorders’ Seminar (see below). Our indoor meeting is a chance to catch up with friends, help plan the year’s field meetings and hear all the latest bug-related news. To join and get the meeting details contact BIG.
On Saturday 28th March there is another insect-focused day: the Conservation Review Day organised by Upper Thames Branch (UTB) of Butterfly Conservation. This is being held in Berkshire, at Dinton Pastures near Reading, but UTB covers Bucks as well as Berks and Oxon, and the day’s events include talks by Martin Albertini and Tony Gillie on Striped Lychnis moth in Bucks, and by Ched George on Duke of Burgundy butterfly in the Chilterns, as well as more general presentations that will be of interest to anyone involved with the conservation of butterflies and moths in the region. Please come prepared to join in the discussions.
Every year BMERC (the local environmental records centre for Buckinghamshire and Milton Keynes) organises a splendid Wildlife Recorders’ Seminar, held as Green Park near Aston Clinton. This year’s programme (Word document download, includes booking form) is in part a celebration of the 25th anniversary of BIG, but also has John Sawyer outlining new developments for the National Biodiversity Network, as well as presentations on freshwater life and water quality from the Environment Agency, and on using DNA for environmental monitoring. BIG then takes centre stage with a series of short presentations from members of the group, and the day concludes with Buglife‘s Sarah Henshall focusing on the invertebrate paradise that brownfield sites can provide. Thoroughly recommended – I should warn you that I’m also down to speak, twice, but both of these are for short periods 🙂
Finally, on Thursday 23 April (and once again at Green Park) there is a fascinating conference with the intriguing title of “Local Spaces : Open Minds” (click for details and booking form). Organised by the Chiltern Commons Project, this day explores what role the Chiltern Commons could play in the environment of the future – how can they best play a part in conserving species, providing outdoor space for healthy living, and contributing to landscape and heritage? You may not realise it, but there are around 200 commons in the Chilterns, many of which have considerable biodiversity and historical interest, as well as playing a role in the wider landscape-scale conservation issues relevant to us all.
Sadly I can’t be at all these events but each looks like it will be worthwhile and enjoyable – join in if you can.
New research suggests that light pollution can reduce mating success in Winter Moths
Moths are in trouble – evidence is accumulating (see Butterfly Conservation and Conrad et al. 2006) to show that many moth species are in decline, especially in the southern half of Britain. But what are the causes? Research is showing that a combination of factors is likely to be involved (Fox et al. 2014), with habitat change or loss and climate change likely to be a large part of the story. But another factor that could be impacting on moths is ‘light pollution’, the tendency for humans to want their own habitat to be lit up at night, so we can work, play and feel safe walking the streets. The night-time glow of towns and cities is visible from miles away, and even in rural areas roads, shops and houses may be illuminated.
Could all this light be affecting the lives of nocturnal creatures such as moths? It seems plausible, but it’s hard to prove, not least because the way most of us go out and look for moths is by putting bright lights out to attract them. How to find out what light pollution does to moths when they’re hard to observe in the dark?
A newly published paper (“Artificial light at night inhibits mating in a Geometrid moth” Van Geffen et al. 2015) has used an ingeniously simple method to investigate this, and the results suggest that we should indeed be worried about what light is doing to moths. Koert van Geffen and colleagues carried out their study in the Netherlands, and chose Winter Moth as their subject. Why Winter Moth? One reason why they make good study subjects is that their habits are a bit more predictable than for many moths: female Winter Moths are flightless, and one they emerge from their cocoons under ground they ascend the nearest oak tree and wait for the males to find them. And there is an established method for trapping them, by setting up ‘funnel traps’ that steer the females into a container once they climb far enough up the oak tree.
So Winter Moths are going to be climbing their oak trees, and if you shine a light on the tree the females can’t fly away. The Dutch team set up a series of different lighting regimes directed at oak trees, using green, white and red light, plus unlit trees for comparison. They counted the females on each tree, and checked them to see if they had mated. The results seem to me to be quite dramatic.
By far the greatest number of female moths were caught from the unlit trees. Of the illuminated trees, white had fewer than red, and green fewest of all. All lit trees had more moths on the shaded side than the lit side, but only under red light did even the shaded side produce anywhere near as many moths as the unlit trees. And there was a big difference in mating success: 53% of females caught from the unlit trees had mated, but only 28% of the females under red illumination, 16% under white, and 13% under green.
Van Geffen et al. also studied male moths using pheromone traps positioned under different lights. The differences here were less dramatic but still apparent, with fewest males caught under red light, more under white, more again under green, and the greatest number from unlit traps.
This is of course just one study of one moth species, but it showed that in this instance artificial light reduces the activity of female moths, and also reduces the male response to female pheromones, resulting in decreased mating success. The lights used in the experiment were LEDs with a light intensity of 10 lux – street lighting can be much brighter than this, up to 60 lux (Gaston et al. 2012).
Relatively simple and effective research, providing more evidence of the pressures on moth populations. Can we do anything to reduce the effects of light pollution? Gaston et al. 2012 review possible ways of preventing too much light escaping into the wider environment. Further useful information and advice is available from Buglife’s research and Campaign to Protect Rural England’s “Dark Skies” pages. For instance, we can reduce the intensity of artificial lighting, direct it more precisely so there is less overspill, and leave lights on for shorter periods so that they are only illuminated when they are actually needed. This not only has the potential to help wildlife, but to reduce energy use and costs as well – moving lighting in this direction has got to be a no-brainer.
By taking action at home and encouraging local authorities and businesses to do likewise we can all help shed some darkness and take moths out of the spotlight.
Having travelled to Shrewsbury last weekend to speak at the excellent Darwin Festival, organised by Shropshire Wildlife Trust and partners, I took the opportunity to do some extreme entomology. Okay, so The Hollies (next door to The Stiperstones, near Shrewsbury) is a bit higher than where I live, 350 metres as opposed to 100 m, but the altitude can’t be said to be extreme. And although a cold, gloves-on February day might not be the usual choice for bug-hunting – the temperature records claim it was 7-8 °C, but with a biting wind it felt a good deal colder – that wasn’t really extreme either, although it did make it hard to keep the beating tray steady. No, the extreme thing here was the trees I was searching for signs of insect life: a range of ancient Holly trees, some believed to be about 400 years old.
The Holly trees at The Hollies are an extraordinary range of shapes. Many are individual isolated trees that have been sculpted by wind and time into gnarled shapes that stretch and lean. There is precious little shelter to be had, either for the trees themselves, or any insects that might live in or on them, or indeed for the visiting entomologist. This must be one of the few Holly populations anywhere in Britain where the Holly Leaf-miner fly (Phytomyza ilicis) struggles to gain a foothold – I found just a few mines on one of the slightly less exposed trees.
But a lot of insects clearly do make their home here, as testified by the peppering of beetle exit holes in the trunks and limbs of the trees. And in fact the first insect to fall out of a Holly and onto my beating tray was the Lesser Thorn-tipped Longhorn Beetle (Pogonocherus hispidus). Larvae of this small (5mm) but attractive beetle develop in the small branches of a range of trees including Holly. Do have a look at thesetwo great close-ups by John Hallmén on Flickr.
An hour or so of beating and grubbing around the trunks of the the trees produced a small list of other species:
Holly Speckle fungus, Trochila ilicina (a tiny fungus that only grows on dead Holly leaves)
A modest list, but not bad for a very cold February afternoon, especially as all but two (Porcellio scaber and Anthocoris nemorum) of these invertebrates are new records for the Stiperstones area, according to the useful list compiled by Pete Boardman in 2010. I find it comforting that these many of these species have probably been happily living at The Hollies for many generations, over the centuries since the current hollies started growing.
The Hollies is a Shropshire Wildlife Trust reserve and SSSI, so thankfully its special character has been recognised and is being looked after. It’s a shame that so many of the hollies have had to be fenced off, making it look rather like a tree zoo – presumably this is to prevent the trees being damaged by grazing stock. But the ancient hollies still work their magic, redolent of centuries of human interaction with the landscape. There’s more about the history of The Hollies on Sara Bellis’s blog, where she comments that in the past small boys would have been sent up the trees to collect the higher, less prickly leaves, as livestock feed. Since I was accompanied on my visit by a small boy in the shape of Kitenet jnr it’s a shame I didn’t think to put him to gainful employment for once …
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.
Dennis, R.L.H. 2010. A resource-based habitat view for conservation – butterflies in the British landscape. Wiley-Blackwell, Chichester. [A densely technical read, but full of insight into the ways in which butterflies interact with their environment.]
Fry, R., and Lonsdale, D. 1991. Habitat conservation for insects – a neglected green issue. Amateur Entomologists’ Society. [Contains lots of good information, but not as easy to use as Kirby’s book, and currently out of print.]
Kirby, P. 2001. Habitat management for Invertebrates – a practical handbook. RSPB, Sandy. [If you only want one book on invertebrate conservation, make sure it is this one!]
Alexander, K., Butler, J., and Green, T. 2006. The value of different tree and shrub species to wildlife. British Wildlife 18: 18–28.
Brooks, S.J. 1993. Joint Committee for the Conservation of British Invertebrates: Guidelines for invertebrate site surveys. British Wildlife 4: 283–286. [Also reprinted as AES Leaflet 38, Site survey guidelines, see http://is.gd/9HcbG].
Key, R.S. 2000. Bare ground and the conservation of invertebrates. British Wildlife 11: 183–191.
Conservation statuses for invertebrate species Information on conservation statuses is dispersed and confusing, but here are the main sources. The nearest thing there is to a complete listing of all species statuses, including invertebrates, is to be found in the JNCC “Conservation Designations Spreadsheet”, a large file (last updated on 23 November 2009).
This includes species listings for BAP priorities, Red Data Books, Nationally Scarce, legally protected and some others. It needs using with care, as the various statuses have been applied at different times (some are now out-of-date) and using varying criteria. The major omission is national statuses for moths, which have never been formally published by JNCC, despite being widely used for many years. The best source for these is: Waring, P., Townsend, M., and Lewington, R. 2009. Field guide to the moths of Great Britain and Ireland. British Wildlife Publishing, Gillingham.
Many of the statuses in the above spreadsheet were originally published in the series of Reviews that JNCC have published. These generally include a good summary of what was known about the distribution and ecology of the rarer species at the time (but some are now rather out-of-date). The older, hard-copy reviews are listed; the latest ones can be downloaded.
For work with invertebrates, two internships are available this year, deadline for applications is 15 June 2009. Mammal internships have been allocated for 2009 but will be available again in 2010 (I see that there are seven mammal internships available, which is a bit unbalanced given the relative number of species to choose from, but far be it from me to criticise funding for worthwhile causes!).
I’m delighted to hear that David Lonsdale has been awarded this year’s Marsh Award for Insect Conservation. Many years ago I volunteered as Conservation Officer for the Amateur Entomologists’ Society, under David’s guidance, and have fond memories of his friendly supervision, his expert and detailed knowledge, and his untiring dedication to the cause of conserving invertebrates. Strong memories also of his beady eye for any deviations from good English and scientific accuracy!
David is still active within the AES, editing their Invertebrate Conservation News among other activities, and also supports the Ancient Tree Forum and Buglife, among others. He (along with Reg Fry) was instrumental in getting the first book published on insect conservation in the UK, the AES’s “Habitat Conservation for Invertebrates – A Neglected Green Issue” (1991).
This award for David is thoroughly well-deserved, congratulations, and long may his inspiring work continue.
Members of Parliament have registered their alarm at the decline in butterfly numbers and said a big thank you to all the volunteers who participate in UK Butterfly Monitoring Scheme.
More than 50 MPs have signed an Early Day Motion tabled by the MP Bob Russell, who represents Colchester and is a long-time Butterfly Conservation member.
It states that:
“This House registers its deep concern at the decline in the butterfly population, with numbers reported by the charity Butterfly Conservation to be at their lowest for 25 years, with the small tortoiseshell showing the biggest decline of 81 per cent; congratulates the thousands of volunteers who each year provide information for the UK Butterfly Monitoring Scheme operated by Butterfly Conservation and the Centre for Ecology and Hydrology; welcomes the comments of Sir David Attenborough, President of Butterfly Conservation, who is promoting an appeal to raise funds for the charity’s Stop Extinction Appeal; and calls on the Government to promote cross-departmental policies to assist in safeguarding Britain’s butterflies”
If you think this EDM should be supported, please check Early Day Motion 8 to see if your MP has signed, and if they haven’t ask them to do so.