I like a mystery to solve! Yesterday at Parke I saw a dock leaf which had been almost completely eaten – only the veins on the leaf remained. I’ve seen such leaves before but had never given them much thought as to who the culprit might be. Yesterday I decided to investigate.
The leaf in question
A close up
I turned the leaf over and found this – initially I thought it was a caterpillar but upon closer inspection I concluded it was a beetle larvae
Then I spotted and few more larvae
And finally on an uneaten leaf I found lots and lots!
Google is a wonderful tool “Black beetle larvae on dock” provided the answer immediately. These are the larvae of a chrysomelid beetle known as the green dock beetle or Gastrophysa viridula – here is a link with more details of the beast. It is a small (4-7mm) metallic green beetle which totally relies on eating dock as a larvae to complete its life cycle.
Despite searching I couldn’t find any adult beetles – it would seem that they have long left the scene of the crime – see the earlier link for photos of the adult.
It is a common species found throughout the British Isles – here is the map from the National Biodiversity Network
Always satisfying to solve a mystery.
On Saturday afternoon we had a short walk from Princetown down the disused railway towards King’s Tor – lovely weather and lots of people.
Looking south to Leather Tor and the plantations at Burrator reservoir
A rather classic Dartmoor pony
And a foal
Down the railway towards Ingra Tor and the Tamar just outside Plymouth in the background
A mushroom feeding on some pony dung – perhaps Conocybe coprophila? (Fungi is not one of the groups of wildlife I know much about!)
A rather splendid yellow mushroom – any ideas? Mushrooms in August – seems an early season?
Back towards Princetown is the new Dartmoor brewery building
I was struck by this icon on the end of the blacksmith building in the car park
– God with an eagle and a handful of thunderbolts in front of the prison!
A lot of swallows still around – waiting for the journey south
A great walk – if you have more time than we did you can walk down the railway and then around King’s Tor – you can see Vixen Tor behind and take in the quarries at Swelltor and Foggintor – recommended – easy walking all the way along the old railway
I mentioned in a previous blog that you can tell different species of bush cricket and grasshoppers by their songs. I have recorded the songs of our two species of cone head bush crickets to demonstrate this. Their songs are very high pitched and quiet – so to make them audible I have used a bat detector which makes the high pitched noises audible via the clever electronics in the box.
I used an old QMC bat detector set at a frequency of 40 KHz.
This is a male long winged cone head – which makes the noise – photographed at the Devon Wildlife Trust’s Chudleigh Knighton heath reserve this week
Here is the female – with the long straight ovipositor – photographed on St Mary’s on the Isles of Scilly in 2008
And here is the song of the long winged cone head played through the bat detector and recorded on my iPhone last week
– its like a vintage tractor chugging along!
Here is a female short winged cone head (short wings and a curved ovipositor) photographed on salt marsh in Exton today
Here is the male short winged cone head – again note the short wings! Photographed on salt marsh in Exton today
And here is the song of the male short winged cone head – recorded yesterday – its like a vintage tractor which changes gear as it goes along.
I was over at Killerton on Thursday for meeting and afterwards in the car park I photographed this bright red and black insect. The insect in an order known as the hemiptera or true bugs – they are identified from other insects by their mouth parts which are adapted to suck the juices from plants or animals – rather like a type of insectivorous hypodermic syringe! After flicking though my ‘Chinery’ – The Collins Guide to the Insects of Britain and Western Europe (possibly the best book in the world) I quickly found the beast – it is a squash bug called Corizus hyoscyami – this species can be muddled up with some of the ground bugs but our species is much hairier.
Historically Corizus was found along the coast of south Britain but in recent years it has spread inland and northwards as far as Yorkshire – a species responding to a changing climate! For more info on Corizus – see here.
Rather a smart looking animal with very detailed marking – feeding on a yarrow flower
In this close up you can see the hairs referred to above
I was over at Finch Foundry during the week having a meeting with Devon County Council and the West Country Rivers Trust about some damage at the intake of the leat in Sticklepath which powers Finch’s water wheels – it was damaged in last winter’s storms.
The sandbags show the area of damage
The damage is not on our land but it is in our interests (along with all the other owners of land along the leat) that it is fixed so that flooding does not occur the next time the River Taw is in spate. Fortunately the WCRT have agree to repair the damage and the work should take place in September – thank you!
As I mentioned in an earlier post August (and September) are the main months for grasshoppers and crickets and as the County Recorder for these animals in Devon I always try and find a couple of minutes when I am at various places to record the species that are present. Whilst at Finch I had a quick look at the fire site on our land where the Sticklepath Fire Show takes place and I managed to record a couple of tiny orthoptera known as groundhoppers.
Here is the common groundhopper – tiny – around 9mm long – note the wing cases do not extend beyond the end of the abdomen
Here is the slender groundhopper – the wing cases here do extend beyond the end of the abdomen. Both species are common in the southern part of the UK but are easily overlooked as they are so small! Both species live on open bare ground
On my way home from work yesterday I stopped at Dunsford Woods in the Teign Valley (managed by the Devon Wildlife Trust and owned by the National Trust) to see if I could locate the population of wood crickets that live there. In a voluntary capacity I am the Devon County Recorder for Orthoperta – that is grasshoppers, crickets and bush crickets.
Wood crickets are native animals and are really rather rare in the UK – if you want to know more about them click here where you will also find a couple of sound files where you can hear their calls – a distinctive thing about most of our orthoptera.
I am pleased to say that I heard around 20 calling males, saw a couple of adults and a nymph. I didn’t manage to take any photographs even though I took my camera and struggled up the very steep south facing woodland edge slopes where they live! However I did get some pictures of the Dunsford wood crickets in September 2008 so I will share those instead.
Wood crickets are black and around 1cm long – they tend to live in woodland glades in deep leaf litter
This is a male – their wings cover about half of the abdomen – their hind wings are absent and as a result they cannot fly. Females have even smaller wings and possess a long ovipositor which extends beyond the two cerci (pointed extensions which can be seen on the rear end of the male above).
Wood crickets feed on dead leaves and their associated fungi
Here is a close up of a wood cricket face
Here is the national distribution – only three main population centres – South Devon, Hampshire and the Isle of Wight
I am currently in the process of setting up a website on Devon’s orthoptera which will give information on all of our species including their distributions. Hopefully I will get that project up and running by the end of the year. Earlier in the year I blogged about our other species of cricket – the scaly cricket which is much, much rarer and lives on the beach at Branscombe – see here for that story.
I was in Fingle Woods yesterday (which is owned and managed jointly by the National Trust and the Woodland Trust) and they must have one of the best populations of wood ants in the south west. There are dozens of nests per hectare and one nest can contain up to 250,000 individuals. Wood ants are social insects rather like honey bees and each colony normally consists of a queen and a host of worker ants. Wood ants are predatory catching other insects and caterpillars but surprisingly get most of their food from ‘milking’ aphids for their honey dew. Wood ants have been found 90′ up trees searching for honey dew. If you want to know more about wood ants see here. The species in Fingle Woods is Formica rufa. They are most common in coniferous woodlands but they do also occur in quite large numbers in broadleaved woodlands such as Dunsford Woods. It is hard to believe that although they are so common (but local) in Fingle Woods and elsewhere in the west and north of Britain that they are rare in the rest of Europe.
A small wood ant nest beside a ride at Wooston Castle
A wood ant – note the jaws – they can nip!
Colonies are busy places
Colonies can be quite dense and close together
And some are huge – this one is nearly 3′ tall