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Posts tagged ‘salisbury plain’

Blue fleabane

Blue Fleabane, Erigeron acer

Blue Fleabane, Erigeron acer

I’ve made a conscious effort this year to improve my botany skills. That’s just a posher way of saying I’m endeavouring to put a name to some of the plants I see when I’m out looking for insects. A number of the people that have helped me with my various surveys are good botanists and so have got used to me pointing to a flower and asking ‘What’s this?’.

At the weekend while out counting bees on Salisbury Plain we spotted this rather unusual looking wildflower which I was informed is called Blue Fleabane Erigeron acris (formerly Erigeron acer)I was struck by its unusual and delicate pale lilac and yellow flowers. Apparently it’s a member of the Daisy family, Asteraceae. It’s a herb thought to be helpful in treating tooth-ache and arthritic pains.

Our smallest resident butterfly

Small Blue butterfly, Cupido minimus, male

Cupido minimus – male

The Small Blue Cupido minimus is the UK’s smallest resident butterfly. Females are chocolate brown whilst males, like the one pictured above photographed recently at Martin Down, have a silvery-blue dusting of scales near the base of the wings. The sole food plant is Kidney Vetch Anthyllis vulneraria and so it is reliant on the type of grassland habitat where this plant can flourish. It favours areas with broken ground.

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Bombus pascuorum

Common carder bee, bombus pascuorum, male

Bombus pascuorum – Male

My favourite bumblebee at the moment is also our commonest, the Common Carder Bee Bombus pascuorum. The photo above shows a particularly handsome, well-marked, somewhat foxy-looking male. Male bees can be handled safely in the field, like this, if held very gently, but if you are in any doubt as to the sex, don’t do it.

This is a species that can vary enormously in appearance and size, in all castes, with some female workers being very tiny indeed. For me this is part of the fascination. Pale-haired specimens can be confused with the rarer carders B. humilis or B. muscorum and may need determining (particularly males) using genitalia extraction. To get to species (useful if you are collecting scientific data) its often necessary to key out a specimen under a stereomicroscope.

For a while now I’ve been thinking I really ought to focus on one group of insects. I really love beetles, Coleoptera, but I don’t find as many as I should. It seems of late that the Hymenoptera (Bees, Ants and Wasps) seem to have chosen me, especially the Bees. This is partially due to where I live, right on the edge of Salisbury Plain – a huge open area of ancient flower-rich grassland and the fact that the Plain holds some particularly rare examples like the Shrill Carder Bee Bombus sylvarum, the Armed Nomad Bee, Nomada armata and the Sainfoin Bee Melitta dimidiata.

But it’s a tough group and as indicated earlier a lot of bees aren’t identifiable beyond family in the field.

Yet in many respects identifying bees, at least in the UK, has just got a tiny bit easier with the long-awaited publication of a Field Guide to the Bees of Great Britain and Ireland by Steven Falk and Illustrated by Richard Lewington. This is the first major work on bees since The Hymenoptera Aculeate of the British Islands by Edward Saunders in 1896.

More info about naturalist Steven Falk and his new book here.

Bombus soroeensis

Broken–belted Bumblebee, Bombus soroeensis

Bombus soroeensis

It’s been many months since I last posted. One Monday morning I went in to work to find that someone higher up the food chain had decided to close our department – I’m now working freelance. Inevitably time has been short while I focus on my new enterprise (it’s gone rather well so far) but I have made time to continue to lead my monthly Beewalks on Salisbury Plain in Areas 15 on behalf of the Bumblebee Conservation Trust.

Although the Shrill Carder Bee Bombus sylvarum has remained elusive we have encountered another rare bumblebee. From July we started observing specimens of what at first glance looked to be small Bombus terrestris or Bombus lucorum female workers but… the first yellow band on the thorax was just a little bit too lemony and the tail although predominantly white had a peachey tinge separating it from the black. Thinking it might be the Broken-belted Bumblebee Bombus Soroeensis we took photos (see photo of male above) and posted these onto the BWARS (Bees, Wasps and Ants Recording Society) Facebook page but at best the overall consensus was ‘possibly’.

On my next encounter, to get a positive determination, I kept a specimen so I could look at it in more detail under my stereomicroscope and key it out. I also allowed Marc Taylor who’d joined us for the day to take a specimen and after he’d examined the sting sheath confirmed he thought it was soroeensis. (Marc is a much more experienced amateur entomologist than I, particularly in regard to things like dissection). I was pretty sure it was too as features on the mandibles and antenna looked good but as I was coincidentally visiting the Natural History Museum in London the very next day I had the good fortune to get David Notton, Head Curator, Hymenoptera, to take a look and he confirmed it was indeed soroeensis. After a celebratory skip, hop and jump I agreed to donate my specimen to the museum for DNA research as the NHM has very few specimens from Salisbury Plain.

It’s rather scarce outside of Scotland and until fairly recently Salisbury Plain in Wiltshire was thought to have the only population of this species in southern England (although new records have come in from the Dungeness area where it was previously unrecorded). Most records from the Plain have come from further East around the Bulford area and we do not appear to have any records this far West in the Centre. But according to George Else who has been recording bees on the Plain since the early 80s ‘it is is very widely distributed over the Plain and locally abundant in a number of locations.’  I’m sure he’s right, it may just be that due to the difficulty in identifying it in the field it is simply under-recorded.

In regard to the photo, that must be a bit of a rarity too as the bumblebee (now confirmed as a male, B. soroeensis) is nectaring on Tuberous Thistle Cirsium tuberosum an even rarer perennial only found in one other location outside Wiltshire. The good news is this year we’ve found good numbers of Tuberous Thistle in Area 15.

Small elephants

Small Elephant Hawk-moth, Deilephila porcellus

Deilephila porcellus

A few weeks back I helped to show a group of Dutch scientists around Salisbury Plain. On Silk Hill we found a couple of freshly-emerged and rather spectacularly-coloured Small Elephant Hawk-moths Deilephila porcellus. It’s a pretty impressive moth with a wingspan in the range of 40-45mm. It can be found in a range of habitats but it prefers chalk and dry grass habitats where its larvae feed mostly on bedstraws Gallium.

More recently I’ve found a couple in my moth-trap along with the slightly larger Elephant Hawk-moth Deilephila elpenor.

Marsh Fritillary

Marsh Fritillary, Euphydryas aurinia

Euphydryas_aurinia

I mentioned in an earlier post that I’ve taken over the role of Entomology Sub-group Leader for one of the conservation groups on Salisbury Plain. Each month I lead a BeeWalk in Area 15 which is one of the artillery impact areas in SPTA (C). Earlier in the year we plotted a 5km transect through a variety of habitat and each month a small group of us follow this route and count and identify the bumblebee species we find. The data is uploaded to the Bumblebee Conservation Trust (BBCT)BeeWalk website. More info about BeeWalk here.

In addition to the bees (which so far have not been numerous) we always find something interesting and this time it was the freshly-emerged Marsh Fritillary Euphydryas aurinia. The day was overcast, great for macro photography in my opinion, as the clouds act as a giant softbox, but there was a real nip in the wind so they were rather sensibly keeping well hunkered down in the grass. To get this shot I had to lie on my belly and wait for opportunities for the wind to drop. Low light can be a problem so inevitably it was necessary to push up the ISO to 800.

As many of you will be aware the Marsh Fritillary has declined in its distribution right across Europe, and is now a protected species and therefore the object of much conservation effort. Fortunately Salisbury Plain remains one of its major strongholds in Wiltshire, the UK and Europe.

Perhaps on my next visit, if it is a little warmer, I’ll get lucky and capture a few images with the wings open.

 

Far beyond the pale horizon

Common Blue butterfly, Polyommatus icarus, female

Polyommatus icarus – female

I’ve recently taken on the role of Entomology Sub-group leader for the Larkhill & Westdown Conservation Group. LWCG is one of three conservation groups that have access to some of the restricted areas of the Salisbury Plain Training Area (SPTA) which is where I took this photograph of a female Common Blue Polyommatus icarus resting on Devils-bit Scabious Succisa pratensis.

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Searching for Arty

Marsh Fritillary caterpillar, third instal

Euphydryas aurinia larva, third instar

It’s taken me two years to find Arty the Marsh Fritillary caterpillar Euphydryas aurinia. I found him when I was out in the Salisbury Plain Training Area searching for larval webs with Mervyn Grist and the Bulford Conservation Group (BCG). Mervyn has been conducting these larval surveys and collecting this important data with the help of the BCG since 2001.

During last year’s survey I didn’t find any. But this year I found three webs, two had been vacated but the second had three tiny black caterpillars inside. One of which is shown above.

The once widespread Marsh Fritillary has declined dramatically throughout Europe and is regarded as endangered or vulnerable in most of its range. The UK is actually one of its remaining strongholds, but even here it has declined by over 60% and has become extinct in much of Britain. However, Salisbury Plain is recognised as an important (and protected) breeding site for the species and fortunately at approx 300 square miles, it’s big, but better than that, it’s right on my doorstep.

Ironically protection for the butterfly has come because the British Army use about 150 square miles of the Plain as a military training area, particularly its heavy artillery and tank units. Subsequently this little butterfly has been nicknamed the ‘artillery fritillary’ or as I call it ‘Arty’. Due to about 340 days of live firing, about 39 square miles are permanently closed to the public, and access is greatly restricted in other areas, although conservation groups like ours can get access on non-firing days, subsequently it’s a wildlife haven and if you like butterflies. A privileged glimpse of what we’ve lost.

The female fritillary will look for Devils-bit scabious Succisa pratensis, crawling down through the vegetation to lay from 150-350 eggs in neat rows on the underside of one of the basal leaves. She seems to have a preference for prominent, medium-sized plants growing in a sunny position. After hatching the caterpillars spin a dense web for protection and after eating the first plant crawl off together to find and spin a web in another. They might do this several times.

Fortunately this makes surveying relatively simple. Spotting the dark purple flowers of ‘devil’s-bit’ is easy enough as is the rather conspicuous larval web. However, there is a lot of scabious on the Plain, which is a good thing, but bending over to check the base of each one, hour after hour, is back-breaking work. Can I just remind you I found 3 webs and 3 caterpillars.

As the caterpillars grow they moult their skin – each of these changes is called an instar. At the third instar they change from greenish-brown to black with a speckling of tiny white spots and rows of short black spines. At the end of August, early September the groups break up and individuals go their separate ways.

The caterpillars will reappear in February or early March after making a new web on a scabious plant where they may be seen clustered together absorbing the warmth of the sun. By early May they will have pupated into a chrysalis and the adults will start to emerge two or three weeks later.

Incidentally the little black dots around the caterpillar are frass (caterpillar poo).

 

 

Juniper green

Green Hairstreak butterfly, Callophrys rubi, Male

Callophrys rubi – Male

I came across this easily overlooked green and gold-edged beauty while out on a 9 mile river amphibia walk on Salisbury Plain. It’s unusual I guess to see a Green Hairstreak Callophrys rubi sitting amongst nationally threatened Juniper Juniperus communis famous for its aromatic berries used to flavour Gin.

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Ash brownies

Brown Hairstreak butterfly egg

The thick overwintering egg case of Thecla betulae

Apologies for my absence. Some of you may be aware that England has been getting a bit of a battering weather-wise. Storm after storm has hit southern Britain giving us almost biblical amounts of rain. It’s felt like it has poured virtually non-stop since December. We’ve had the wettest January since records began. February has been much the same leaving most of Somerset under water.

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