A giant horsefly at Parke

For me the best bit about this fabulous hot and sunny weather is that it really brings out the insects! A couple of days ago I was in the wet meadows at Parke and saw this very large horsefly quartering the grassland. I managed to net the insect first time and successfully transferred it to a pot so I could inspect it more closely. I brought it back to the office and put it in the fridge for half an hour to calm it down. I was then able to take the following photographs.

As you can see it is a very large horsefly – yes that is a £2 coin which gives you an indication of its size.

This species is Tabanus sudeticus or the Dark Giant Horsefly – this is a female (you can tell the sex of the adults by looking at the gap between the eyes: gap = female and no gap = male. This individual is 25mm long! This is as large as horseflies get anywhere in the world including the tropics. The orange antennae and black bands on the abdomen are diagnostic of this species.

Here is a frontal view – the long ‘dagger’ under the antennae are the mouth parts. Horseflies as we all know suck blood from animals such as cattle and horses. It should be noted that it is only the females that drink blood and they only do so when they are preparing to lay their eggs. The rest of the time they feed on nectar from flowers.

Here is the UK distribution of the Dark Giant Horsefly – it has a limited distribution and is much rarer than it once was.

Last year I was in Scotland and the Lake District and on both occasions I found Dark Giant Horseflies – here are some photos I took from the National Trust’s property Aira Force.

In case you are thinking of having nightmares – these giant horseflies don’t like human blood and instead specialise on horses and cattle. Other horseflies – particularly the clegs and the gadfly do bite humans but are much smaller – nevertheless the bites are painful and irritating so watch out! Clegs have skinny red eyes and gadflies have shiny green eyes in case you are wondering ….

You will, I am sure also be pleased to hear I released the animal back into the wilds of Parke after I had finished photographing it – maybe you will come across it too.

 

 

You’re taking the mimic!

To the casual obeserver the following insects look like bumblebees. In fact they are hoverflies mimicking bumblebees – very clever impersonators!

Obviously bumblebees have a sting which they use as a deterrent – a young bird which catches a bumblebee will inevitiably get a nasty painful sting. That sting will kill the bumblebee but will act as a deterrent the next time that bird sees a bumblebee. Instead of catching another bumblebee it will go and hunt something else.

By mimicking bumblebees the hoverfly will gain the ‘group’ protection of looking like a bumblebee!

This is the hoverfly Volucella bombylans – it looks very similar to a white tailed bumblebee

A close up allows you to see it has fly-like eyes opposed to the much smaller bee-like eyes.

This is the hoverfly Cheilosia illustrata – note all the furry hairs and the red tail – this is mimicing the Early Bumblebee Bombus pratorum.

Funny thing evolution!

The burnet and its companion

Visited Plymbridge yesterday to get an update on various projects – we did have time also to visit the meadows.

A lovely 5 spot burnet – feeds on birds foot trefoil and is rather a local species

And this is a burnet companion – a day flying moth

Its larvae feed on clovers or birds foot trefoil

 

Who killed the beautiful demoiselle?

I found these four wings on the bank of the river Teign at Fingle Bridge last week. Who is the killer?

These are the wings of the beautiful demoiselle damselfly.

As you can see the wings have been plucked from the body and presumably the body has been eaten by a predator. I have been thinking and speculating about who might be responsible. I have found the dismembered wings of moths piled up in a place where long-eared bats feed – so perhaps a bat feeding along the Teign is responsible? Maybe but bats tend to be nocturnal and damselflies are day flying. There is some overlap around dusk so a bat is a possibility.

Hobbies (the small falcon) also preys on dragonflies and damselflies (along with swallows and martins) and there are certainly hobbies in the vicinity.

I also wonder whether this is the work of a flycatcher – either a pied or a spotted.

I guess we will never know. In case you are wondering the wings are removed as they are not very nutritious compared to the main body.

Here is a picture of a complete beautiful demoiselle taken last summer

Two new longhorn beetles in one day

A few weeks ago I wrote a post about the longhorn beetles of Parke – at that point we had recorded 8 different species. Longhorn beetles are interesting as they are indicators of ancient and deadwood habitats and as a result many are quite uncommon.

Yesterday a Parke we added two new species to the list! Our Ranger Fred Hutt found the following species – in fact it crashed into his face! As you can see it is a pretty sizeable insect.

It is around 30mm long excluding the antennae – it is called the Variable Longhorn Beetle (Stenocorus meridianus)

It is another species which lives as a larvae for 3 years eating the stems and roots of deadwood

An interesting gold sheen

A reasonably common species in the south but rather uncommon in Devon (map courtesy of the National Biodiversity Network)

I found the other species which is the same species as I found yesterday at Fingle Bridge – it is the Speckled Longhorn Beetle (Pachytodes (Judolia) cerambyciformes).

Wonder which species we will find next? It just goes to show that the parkland and the way we manage the deadwood habitats works and is really valuable for wildlife.

The Devil’s Coach Horse

When I was at Hembury Woods the other day I found a Devil’s Coach Horse beetle. I haven’t seen one for years but do remember them distinctly from my youth. The Devil’s Coach Horse is a type of rove beetle.

It is quite a large all black beetle

They are well known to offer up their large jaws in this threatening posture when disturbed

They also flick up their tail and as a result are sometimes also known as the Cock-tail beetle.

Fortunately it didn’t happen to me but they can also exude a foul smelly substance when provoked. They tend to feed on other invertebrates such as woodlice and worms.

 

Here is the national distribution of the Devil’s Coach Horse – according to this it has only been recorded in Devon in the Plym Valley area – new record for Hembury maybe?

Dark green fritillaries

Dark green fritillaries are now out on the wing. I spent quite a bit of time over the weekend at Hembury Woods on the Dart looking for dark green and high brown fritillaries – none of the latter yet but plenty of the former.

Dark green fritillaries are large fast flying butterflies – over the last 50 years they have undergone big declines but are still reasonably common in Devon and on Dartmoor (in the valleys opposed to the high moor). For more information of dark green fritillaries see the Butterfly Conservation website here.

Here are a few photos which I managed to get when they finally stopped flying around!

 

Dark green fritillaries are very difficult to tell from high brown fritillaries (which are much rarer and more endangered). The most reliable feature is the underwing pattern shown above.

The chafer and the chimney sweep

Both the following species are now out and about.

This is a moth called the chimney sweeper – a black moth with white tinges on the ends of the wing

It is a species of unimproved meadows – it has become rarer in the south of Britain in recent years as unimproved meadows have been ploughed up

The caterpillars of the chimney sweeper feed on pignut which on Dartmoor can be a common species in grassland so keep you eye out for the chimney sweeper

This is the garden chafer beetle – I have been seeing these animals everywhere in the last few days – they are obviously having a good year and the warm weather has helped them metamorphose from pupae to adult. In the wild they do no harm but they can be a pest of formal lawns ….

At Hembury Woods with a western bee fly

I spent an hour or so over at Hembury Woods in the baking sun yesterday – I had hoped to see a high brown fritillary but no luck there (it is very early in the season for them but they have already been recorded on Dartmoor this year) – instead I found a few other nice insects. The highlight for me was the Western Bee Fly which is very localised nationally.

The Western Bee Fly Bombylius canescens

The characteristic long ‘nose’ which enables it to feed inside long flowers

The UK distribution of Western Bee Fly – it has a designation of ‘Nationally Notable’ on account of its rarity

Hembury is also home to a strong population of tiger beetles – one of my favourites!

Tiger beetles – Cicindela campestris – are well distibuted across the UK but need warm and sandy soiled places

Finally I found this long horn beetle Strangalia melanura

Relatively common beetle in southern Britain but quite uncommon in Devon and Dartmoor

All maps are courtesy of the National Biodiversity Network

 

Heath spotted orchids

A couple of photos of heath spotted orchids beside Fernworthy Reservoir.

Spotted leaves and  white / pink flowers

Spotted orchids can be notoriously difficult to identify but I think these are heath spotted orchids