Tag Archives: insects

The birds and the bees

Insects have been hit hard by climatic aberrations in recent years and on my meanderings around the Cambridgeshire countryside this year numbers of bees and butterflies sightings have been down compared to previous years. It’s now the middle of June and I saw the first dragons of the year today; two damselflies. I also read this week in ‘The Guardian‘ newspaper that a third of managed honeybee colonies in the USA were wiped out in 2012. This article makes very sobering reading. And it’s a similar story in Europe, but in Europe neonicotinoid pesticides, which have been implicated in colony collapse disorder, have been banned for two years to evaluate their effect on honeybees. My concern is that the onslaught on the bees is complicated and removing one variable may not show a significant effect in the limited two year duration of the ban. But I hope it does!

Early last month the sun finally broke through and gave us some insect friendly weather and it was remarkable how quickly the microfauna emerged.

Beefly – Bombylius major

Beeflies are found over large parts of the globe and can be seen hovering in sunny glades from the springtime. The narwhal of the Dipteran world, the spike looks fearsome but is only used to probe flowers for nectar, there is  no sting. Beeflies procreate by flicking their eggs into the entrance to the burrows of wasps and bees where the larvae feed on the grubs of the occupants.

A pair of hoverflies doing their best to rectify the decline in the insect population

I think these hoverflies are ‘Eristalis pertinax’ but I’m not certain. It was good to see them though, especially as they were taking their biological responsibilities so seriously.
Addendum: on the subject of climatic aberration mentioned at the top of this post I just found and read with increasing concern this link:

http://robertscribbler.wordpress.com/2013/04/12/human-climate-change-is-wrecking-the-jet-stream-uk-met-office-calls-emergency-meeting/

which my blogging buddy Sam posted on her excellent WP blog ‘Science on the Land‘. This provides a chilling insight (in every sense) into why the weather in the northern hemisphere is behaving the way it is. And it doesn’t look as though it’s going to get any better folks.

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Anachronous insecta

A few posts ago I showed you some of the spider I encountered in the short spell of good weather we had in the late summer and early autumn. I think maybe some species were making hay whilst the sun was shining because there were also a lot of hoverflies around at that time too. And here are  three of the species I found. It’s the wrong time of year to be posting about hoverflies, hence the title of the post, but I haven’t been able to get out with my camera so I reckon a hoverfly post is better than none at all! Identifying hoverflies can be tricky because there are species which look very similar to each other and I’m no expert, so I hope my identifications are accurate but if any of you spot an error please let me know.

Eristalis tenax

Eristalis tenax is a type of hoverfly known as a ‘drone fly’, so called because they mimic honey bee drones. They are common throughout the UK and the females, which mate before overwintering and laying their eggs in the springtime, can be seen in any month of the year because they emerge from hibernation to feed when the weather warms up sufficiently. The larvae of this species are called ‘rat-tailed maggots’ and feed in sewage outflows and rotting carcasses – the more putrid it is the more they seem to like it! They are aquatic and the reason they are called ‘rat-tailed’ is that they have an extendable tube which can protrude up to around 5cm which they poke out of the water and use to breath air.

Tapered drone fly – Eristalis pertinax

The tapered drone fly is so called because the male has a tapered abdomen which is visible on this individual. It is otherwise a similar species to E. tenax and it’s larvae are also known as rat-tailed maggots. Apart from the taper it’s also distinguishable from E. tenax by it front legs which are pale.

My favourite hoverfly I found this year is this one:

The footballer – Helophilus pendulus

It’s called ‘the footballer’ because it’s colours are likened to a football shirt. It’s scientific name means ‘dangling sun lover’. The larvae of this species feed on detritus and have been found in wet manure, drains and in very wet sawdust. It’s widespread throughout the UK and can be seen throughout the summer in bright sunny locations in hedgerows. Despite the unsavoury but indispensable habits of the larvae of all of these species they transform into the most handsome adults.

I haven’t done a dedicated Christmas post this year so here’s wishing you all a very merry Christmas and a happy and healthy 2013!

The Isle of Wight, Part 2

My first view of the Needles, at the western tip of the Isle of Wight, was a long time ago when I flew round them in a light aircraft. The weather was much like it is below and it was quite a spectacle!

The Needles looking across to the Isle of Purbeck. Old Harry Rocks are the thin sliver of white chalk in the distance at 11 o’clock from the lighthouse

I’d heard it said that the Needles were at one time joined to the Old Harry Rocks at the southern end of Studland Bay, around 15 miles away on the Isle of Purbeck. I’d thought it entirely possible but never had it confirmed. And then just after I took this photograph I overheard a very knowledgeable old gentleman telling his companion all about the local geology, so I stood close by and earwigged the conservation.

As you can see, the Needles are made of limestone and apparently they were once a single strip of rock with a gap in the middle from which a single calcareous stack protruded, known as ‘The Needle‘. And then in the 18th century a storm caused a collapse which resulted in the Needles of today.

But before that, Old Harry and the Needles were a single limestone structure and the Isle of Wight wasn’t an Isle, and the Solent – the stretch of sea which separates the Isle of Wight from the mainland – was the River Solent. But around 4-5000 years ago a storm breached the limestone wall and the River Solent became a seaway overnight and the inhabitants of the Isle of Wight were cast adrift on a new island. And interestingly, all the rivers on the mainland from Poole Harbour in the west eastwards to Portsmouth: the Meon, Itchen, Test, Avon, Frome and Piddle all flow southward, and those on the Isle of Wight: the Eastern Yar, Western Yar, Newtown, Wootton Creek and Medina all flow northward, and they all drained into the River Solent.

Pyramidal orchid – Anacamptis pyramidalis

The terrain all around the Needles is chalk downland which has very characteristic flora and fauna, amongst which is the pyramidal orchid and this lone flower was lurking at the edge of The Needles carpark. It thrives on the chalk downs to such a degree that it has been chosen as the county flower of the Isle of Wight. In the air high over the car park was a peregrine falcon (Falco peregrinus, Dansk: vandrefalk) but I didn’t have a telephoto lens with me on this trip, so alas, no pictures. From the car park it’s about a mile to walk to The Needles themselves and on a sunny day it’s a terrific walk, the views are magnificent.

To the east, north and west the air was full of falcons, songbirds, bees and butterflies, and when we got to the very end there was a historic naval gun emplacement. In WWII the gun guarded the Solent and the strategically important ports of Poole, Southampton and Portsmouth against enemy shipping, and just over the top of the cliff from the gun emplacement was a test site for missile engines which had been hewn from the rock – a hangover from the Cold War. The whole thing was fascinating, geologically, biologically and historically!

Teasels – Dipsacus fullonum

Whilst trying to photograph a stonechat which was darting around next to the path I noticed these teasels which were still sporting their downy purple flowers. I have lots of photographs of the dried out brown seedheads of teasels after they’ve flowered but but I’ve been after a good one of the flowers themselves. And I think this is the best backdrop I could have found, looking out across the Solent towards the New Forest on a sunny day.

Also flitting around in the chalky grassland were hundreds of chalkhill blue butterflies. It was a very windy day and I think the butterflies may have been staying down low becausse of the wind, preferring to be stationary rather than risk being blown away. Consequently they were fairly easy to get close to:

Chalkhill blue male (Lysandra coridon)

I absolutely love blue butterflies. In fact anything living and blue – insects, flowers, fish reptiles – blue seems to convey a unique beauty on a creature, so to see so many of these blues was a real pleasure. And the chalkhill blue is a big butterfly too, with a wingspan of 33-40mm.

One of the curious facts about blue butterflies is that some of them are actually brown, and with chalkhills as with common blues, the females are brown:

The female chalkhill blue. She’s brown, not blue, but still a beauty!

Chalkhill blues mating, the brown female is on the left

Apparently this year was a particularly good one for the chalkhill blue. Despite being a devastating one for most other butterfly species in the UK, there were huge numbers of breeding chalkhills recorded in their traditional territories, and in my humble opinion that’s very good news indeed.

The view along the north of the island looking east towards Southampton, with yachts racing toward us

The geology of this part of the south coast is remarkable too. Limestone was formed at the bottom of oceans by the compaction of dead shellfish over millions of years, so it may seem odd to find it at the top of the cliffs. Or indeed whole cliffs made of it. There is a clue to how this happened in the cliff below, which is looking round to the southeast from The Needles, in which there are clearly delineated strata in the rock running upwards from left to right at around 45 degrees. The reason for angled strata is that in this part of the world tectonic shifts have concertinad the rock strata all the way from the east of England along the south coast as far as Dorset to the west forcing them upwards.

This folding of the rock means that in the east the rock is relatively young but the deepest, oldest, layers have been exposed in Dorset around the town of Lyme Regis. So the region around Lyme is referred to as the ‘Jurassic Coast’. Of which more in a subsequent post.

Back yard safari

A couple of posts ago I described my Fenland safari and since then I just happened to have had my own ‘back garden safari’! Lots of colourful creatures have been stopping by to refuel.

I’ve previously expressed concern for the depleted populations of insects, in particular butterflies and dragonflies, due to the mad weather we’ve experienced in the UK this year, but in the last couple of weeks there have been some great sightings outside my back door.


Common darter (Sympetrium striolatum) female perched on the clothes line

The dragons have been late to appear but since the last week in August there have been common darters regularly alighting and migrant hawkers hunting overhead.

And of course it’s that time of year when the arachnids are most in evidence, and my garden is festooned with garden spiders, there are webs attached to every surface: walls, plants, windows… everywhere.

Garden spider female, Araneus diadematus, despatching her prey, a small fly

The female garden spider has a bulbous abdomen which is adorned with the fabulous diadem that gives the species its name. The male is smaller than the female and has a flatter, kite shaped, abdomen, but he also carries the diagnostic markings. A couple of years ago I posted about the perilous love life of the garden spider, suffice to say the sex life of the male can be dramatically and terminally curtailed if he fails to show the lady sufficient respect!


This garden spider male set up home inside the bedroom window – until  the resident arachnophobre found him and relocated him

As well as the spiders, the occasional cricket strolls by, and this little chap was taking shelter under a sunshade from the unseasonally hot weather last weekend:


Oak bush cricket – Meconema thalassinum – the male of the species. The female has a long, upturned ovipositor protruding from her rear

The oak bush cricket is quite a small example of the genre, they are 13-17mm long and are carnivorous, feeding on small insects. They live on the edge of woods and in gardens and appear from July into the Autumn.

Also putting in a welcome appearance was a common buzzard, Buteo buteo:

The buzzard has been one of the birds which has really bounced back since the more stringent controls on of agricultural pesticide use were introduced in the 1980’s. I’d never seen a buzzard until I was in my 20’s and even then it was the occasional sighting in the wilds of west Wales or down in Cornwall. But they can now be seen over all of England – even from my garden.

Hoverfly – Volucella inanis

Hoverfies rarely have common names, they’re simply known under the generic name ‘hoverfly’. And V. inanis is no exception, at least as far as my research reveals. There was great excitement when it first buzzed into the garden because at first glance we thought it was a hornet due to it’s size and its yellow and red colouration. And it was a whopper! They can grow up to 15mm long and this one was one of the bigger ones. It eventually settled and posed rather obligingly on the edge of the rabbit run while I snapped a portrait, and it is a very handsome fly. It has an interesting breeding tactic too laying its eggs in the nests of other social wasps, including hornets – which probably explains its size and colour scheme – where they hatch and feed on the larvae of the host.

Comma – Polygonia c-album

I waited expectantly for this comma to open its wings and show the gorgeously ragged orange symmetry, but it didn’t. So I had to content myself with this silhouette of it perched on a cooking apple.

Damsels of Fen Drayton

One of the reasons for my trip to Fen Drayton a few weeks ago was to have a look to see which of our dragonflies were out and about. I went in early June and that time of year is a little early for the true dragons to have emerged, although it’s not impossible. But despite the shortage of the true dragons, the hedgerows and lake sides were abuzz with damselflies.


Male red-eyed damselfly – Erythromma najas

Dragonflies and damselfies are the two members of the taxonomic order ‘Odanata‘ or Odanates. There are two sub-orders within the Odanata: the Anisoptera – the true dragonflies, and Zygoptera – damselflies.

Azure damselfly – Coenagrion puella – the blue form of the immature female

Damselflies in the UK are approximately 4-5cm (1.5-2 inches) long and have thin abdomens and are all smaller and more delicate than the chunkier dragonflies. Having said that, the biggest living Odanate is currently a damselfly who resides in the rainforests of Central America, it has a wingspan of 19cm (7.5 inches) and the abdomen is 10cm (4 inches) long. A real whopper!

Blue tailed damselfly – Ischnura elegans – immature femaleBlue tailed damselfly – immature male – Ischnura elegans

Male and female Odanates, and immature and mature individuals, can often be distinguished by colour. The common blue female below is conspicuously brown so the species gets its name from the electric blue colour of the male. The common blue can easily be confused with the variable damselfly which is the same blue colour, but they are distinguished by the black markings on segment 2 of the abdomen which is shaped like a goblet on the variable and a club on the common blue. Also, the antehumoral stripes (on the side of the thorax) are complete on the common blue and broken on the variable. Although, as the name suggests, the variable is indeed variable and it can make distinguishing the two species a little tricky.


Common blue damselfly female – Enallagma cyathigerum – the only common blue we saw on this trip, perched on my friends finger

The black goblet on segment 2 is visible under the front of the wings on the variable damselfly below. But confusingly, it’s living up to its name because the antehumoral stripes are unbroken.

Male damselflies have two sets of paired claspers at the end of the abdomen which it uses to clasp the female on her pronotum, which is the protrusion in the middle of the back of the head. The claspers have tiny hooks on them which match grooves in the female pronotum and in order to avoid procreational mismatches the hooks and grooves are species specific.

Variable damselfly – Coenagrion pulchellum

In the picture above a variable male has clasped his lady by the pronotum. Male damselflies have primary genitalia at the end of the abdomen on the 8th segment, but in order for fertilisation to take place he needs to transfer a ‘spermatophore’ from the primary genitalia to the secondary genitalia on the second segment at the thoracic end of the abdomen. The female then curls round in to the ‘wheel’ position to transfer the sperm to her genitalia which are underneath her 8th abdominal segment.

A pair of variable damsels in the wheel position

All the Odanates are carnivores, and the larvae which hatch from eggs layed under water are ferocious carnivores, the larger ones will even take small fish! On one occasion last year while I was photographing large red damselflies (Pyrrhosoma  nymphula), a large hawker dragonfly (I think it was a migrant hawker, Aeshna mixta) which had been buzzing around higher up for several minutes suddenly dived down and caught one of my large red damsels. In a few seconds the migrant butchered it and ate it on the wing and the inedible bits of wing and leg were discarded and rained down around me.

Scarce chaser – an immature male

A lone Anisopteran, or ‘true’ dragon was spotted on this trip and it was an immature scarce chaser, Libellula fulva. He was a lovely mustard colour and he can be differentiated from the female by the colour of the thorax which is dark grey in the female, and from the male adult who is electric blue. He undergoes quite a transformation in transitioning from immature to adult.

Roesels bush cricket

A couple of weeks ago I was sitting at my dining table gazing out the window when I spotted this silhouette throught the blind:

So I snapped a picture and I really like the detail through the blind. It’s clearly a cricket, and a male (it lacks the long pointed ovipositor of the female which would be protruding from the back end) and its very long, very fine antennae are visible too.

So I popped around the other side of the blind to take a proper photograph, which unfortunately had to be through the window:


The markings on this creature suggest he’s a Roesels Bush Cricket

I went on to do some research on the Roesels bush cricket, Metrioptera roeseli, and it turns out it’s quite an interesting creature. It is a European species, named after the German artist and entomologist August Johann Rösel von Rosenhof, which found its way to England in the late 19th century where it established a toe hold in the far south east, in Kent and Sussex, where it remained for several decades. In the last few decades, possibly assisted by climate change, it has spread over much of south east England and the Midlands.

The migration of this species may have been assisted by the road network which could provide conduits for travelling further afield. There are two forms of this insect, the macropterous or long winged form, and a short winged form. It is reasonable to imagine that the long winged cricket would migrate further and faster, but even though Cambridgeshire appears to be towards the northern periphery of their range this short winged individual has arrived here too.

Roesels bush cricket is distinguished from all other bush crickets by the yellow/green edge to the hard cover of the thorax – the ‘pronotum‘ – and the light spots immediately behind the pronotum. One other similar species, the bog bush cricket, also has a light edge to its pronotum but it doesn’t extend all the way round as it does with Roesels bush cricket.

I’d never heard of Roesels bush cricket before I started trying to identify this individual, and then a few days later I was rooting around in the undergrowth of a field of scrub, also here in Histon, and I spotted a creature which I thought was a very green grasshopper. I managed to fire off a couple of photographs and when I uploaded the images it turned out to be a cricket not a grasshopper:


The macropterous form of Roesels bush cricket

And it was another male Roesels bush cricket but he clearly has the long wings of the macropterous form which extend well beyond his abdomen. So it appears I’ve found both forms of this colourful creature within a week. It’s amazing what can be found by poking around in the long grass!

Insectivora

The hedgerows and the edges of country paths are home to an immense variety of small creatures, especially those which aren’t in the firing line for agricultural chemical spraying, and it can be easy to overlook them.

Last weekend I spent a morning chasing insects around and I followed a red admiral butterfly into a thicket of nettles where it sat tight with it’s wings closed. Over the next twenty minutes it very briefly opened its wings, but only partially, but enough to enable me to see that its colours were pristine:

And then it opened them fully, and the colours really were sumptuous:


…well worth half an hour stood in a nettle bed!

But I thought the half hour definitely wasn’t wasted when I looked down at my feet and saw this cluster of peacock caterpillars eating nettle leaves:

I moved to one side to get some pictures of the caterpillars, and fortunately after I’d spent some time doing that the red admiral was still in situ.

Peacocks are hardy butterflies which can be found over most of the UK including the Shetland Isles and can be found hibernating in garden sheds. They emerge from hibernation at any time of year if the weather is warm enough, they mate in March and lay eggs then the caterpillars can be seen from the middle of May into July.

Not only are they hardy, they are quit beautiful too. A close look at their wings reveals a fabulous array of brightly coloured detail:

Male peacocks hold fort in their territory and wait for passing females to pass by when they fly up to greet them and attempt to mate. Male and female peacocks are very difficult to tell apart and watching the males performing this courtship behaviour is one way to differentiate the genders.

And close to the same spot I was looking at the flowers and I spotted this hoverfly cleaning his eyes:

…and this beetle wandering over a convulvulus flower, I don’t know what it is but it has gorgeous colours:

The brambles in the hedgerows were also full of bees in the sunshine, many species of honey bees and bumble bees were harvesting nectar from the flowers:


White tailed bumble bee flying from flower to flower feeding on bramble nectar

And than this marvellous creature was hunting in my kitchen last week:


Violet ground beetle, isn’t he magnificent!

Violet ground beetles are carnivorous, as are their larvae. They hunt at night and hide up during the day under log piles or other cool dark places. They eat a variety of insects, including a number of species that gardeners would be glad to be rid of. They’re big beetles, around 3cm long, and they have irridescent blue or violet edges to the thorax and wing cases. So don’t use chemicals in your garden – let these guys get rid of your pests!

And now I’m looking forward to some warm sunny July days when the surrounding fields are full of butterflies. I’ll share some more insect photographs with you then.

The birds and the bees (and the flowers)

As our warmest and driest Spring on record turns into what is shaping up to be a warm and dry Summer, nature’s great events are occurring apace to exploit the prevailing climatic conditions.

The first swifts were seen over Histon 3 weeks ago (by me at least) after their heroic journey back to their breeding sites from overwintering in Africa. To celebrate this event I’ve spent several hours sitting in the garden of the Castle pub on Castle Hill in Cambridge enjoying a few convivial sharpeners and watching the swifts shrieking through the sky like an avian aerobatic team. I can heartily recommend both activities!

Wild flowers, including one of my favourites, white campion, are now in bloom:

White campion, Silene latifolia, decorating ditches and hedgerows

White campion is a dioecious plant which means the male and female reproductive machinery are on separate flowers. It grows in well drained earth and flowers from Spring to Autumn and is now delineating my walks across the open countryside. Another one of my favourite wild flowers is red clover (Trifolium pratense) which is a gorgeous colour and provides nourishment for bumble bees:


Red clover flower being harvested for pollen and nectar by a common carder bee (Bombus pascuorum). This is the national flower of Denmark.

And of course the local birdlife has been very busy breeding and raising chicks. Alot of species started this process earlier this year due to the unusually warm weather in Spring. I have a pair of blue tits raising a brood in the nestbox in my crab apple tree and my friend told me of a family of song thrushes which fledged from his garden a month ago. Which is very early.

A pair of great tit have been feeding their chicks on crushed peanuts which I put out on my bird feeder over the last month and last week they fledged and the whole family were feeding in my garden for just a day or two before they ventured further afield. (If you put nuts out for the birds during the breeding season please make sure you use crushed nuts as inexperienced parents can try to feed whole nuts to chicks and this can have fatal consequences). Great tits have over 70 different vocalisations which I think is remarkable, almost simple language! And on my explorations along the fields and hedgerows around Histon last weekend (21st May, 2011) I saw more great tit, blackcap and whitethroat all feeding gangs of fledglings:


Common whitethroat male, Sylvia communis

There are two species of whitethroat to be found locally, the common and the lesser (Sylvia curruca). They are distinguished by their song, which I won’t try to describe because I’ve never yet read a book which gives the remotest idea of what birdsong actually sounds like by a written description! But if you want to compare them try here for the common whitethroat, and here for the lesser whitethroat.


And another male whitethroat, this chap was singing long and loud, punctuated with characteristic jerky flights straight up in the air and back to the same spot

There are a good number of common whitethroat in the hedgerows north of Cambridge, lesser whitethroat are also here but are not so numerous. There are other distinguishing features between the two species, the lesser, as the name suggests is smaller (~11cm long compared to ~13 for the common), and is generally more grey with a pale grey head and noticeably darker grey ‘ear’ patches. It also has dark grey legs. Both species overwinter in sub-Saharan Africa, the common in central Africa and the lesser in eastern Africa.

Linnet can be regularly seen flying around the bramble thickets on the edges of the village and perching and singing on top of them. On Saturday early in the morning a fracas was going on in an elderbery tree in Rowleys Meadow in Histon which ended when a jay was chased out of the tree by a family of linnet and a family of whitethroat. The jay alighted on an adjacent shed to suss out the lie of the land and contemplate another raid whilst the indignant songbirds dispersed into some scrub to hide. Eventually the jay decided to keep his powder dry and disappeared into a nearby wood. Jays, like other members of the crow family, will raid nests of smaller birds for eggs and chicks, so it’s a perilous business being a small bird with a family to rear.


A linnet male perching on a bramble. When they’re not protecting a nest I’ve managed to sneak within 15 feet of linnet perched like this.

Linnet, Carduelis cannabina, are abundant resident and migrant breeders, although their numbers, as with many of our songbirds, are declining, and they are also passage and winter visitors. Due to their declining numbers over the past 40 years or so their conservation status is red, indicating they are globally threatened. They are finches which live in open country and farmland and feed on seeds.

Many species of moths, butterflies, bees, flowers and a plethora of other creatures are all appearing as trhe seasons are progressing and there’s something new to see every week!

Orange tip

I am of course referring to the butterfly, not an unsightly medical condition. I’ve spent plenty of time chasing them along hedgerows waiting for one to settle on a flower, but in vain, and you may recall that in a previous post I said that the orange tip was extremely difficult to photograph because they rarely settled.

That was until last weekend when, the weather was sunny, warm and calm so I went for a walk on Guns Lane to the north of Histon. I was rewarded fairly soon into my walk by a male orange tip settling on a plant on the edge of the pathway and allowing me to encroach within just a few inches:


Male orange tip. I think his underwings are exquisite, and it’s perfect camouflage when he’s perched on a cow parsley flower head.

This fellow was a good omen. Several hundred metres further along the path where the dense hedgerow thinned out into more open territory lined with cow parsley there were many male and female orange tips and they were all intent on mating on this particular morning.



Another male orange tip, this time with his wings open. And the colours on top are gorgeous too.

The female of the species doesn’t have the orange tips but is still distinctive from the other white butterflies:

Female orange tip. She is aware of the presence of males and is pointing her tail in the air in preparation for mating…

…and a few seconds later a male flew within a few centimetres and her reproductive organs are clearly visible opening up here in response to his presence.

The female above didn’t mate in this instance, but:

This pair were mating on the ground close by

And another female sits on a leaf as the male beats a post-coital retreat top right

I promised some pictures a few weeks ago of orange tips in the post ‘Local Lepidoptera’ so I was very pleased to capture this series of the mating behaviour so soon after.