Late November 2013

Although the weather has been getting colder there are still some flies about. In particular beating dead leaves on trees and shrubs can often dislodge overwintering Tephritid flies. These flies form galls on various plants but particularly members of the Asteraceae, daisy family. Each fly species is associated with particular plant species and the galls are firmed in particular parts of the plant. One of the commonest species is Urophora cardui, which forms a distinctive gall in the stems of creeping thistle Cirsium arvense. Several of these were present near Yardley Chase on 21st November.

Swollen stem of creeping thistle caused by the Tephritid fly Urophora cardui. The fly itself is very distinctive, having black wing markings of two inverted U shapes that are joined on the trailing edge of the wing. If the two U shapes are not joined, this is another species.

Urophora cardui

Apart from the above gall, adults of other Tephritid flies have been noted over the past couple of weeks: Tephritis formosa, T. neesii and T. hyoscami all in the Yardley Chase area. All of these flies have distinctively patterned wings and are frequently referred to as "picture wing flies". The term covers members of several families, not just the Tephritids. 

It is possible to find the galls of these flies in the heads of various thistles in winter. If you squeeze the dead flower head you can sometimes feel a hard capsule inside, which is the gall. It is possible to raise the adult fly from the gall to confirm which species has made it.

Other signs of the larvae of flies in winter can be leaf mines. Here is blotch mine in the leaf of hedge woundwort Stachys sylvatica. This is caused by the Agromyzid fly Amauromyza labiatarum. It was found at Yardley Chase.

Early November 2013

Although it is getting colder and wetter there have been some fine sunny intervals and in sheltered spots there are still plenty of diptera about. I was looking at some flowering ivy at the edge of Rothwell on Monday and it was covered in flies. These were mainly muscids and calliphorids but a few hoverflies were present: Eristalis pertinax, E. tenax and a Syrphus species. There were several Mesembrina meridiana there too. Here are some photos.

Eristalis tenax

Eristalis pertinax

Mesembrina meridiana (Muscidae)

In my own garden the ivy has not flowered but I do have a plant of the ivy x Fatsia hybrid Fatshedera. This does produce ivy-like flowers, which start to open in early November. It provides an extension to the nectar season. On Monday Episyrphus balteatus was visiting it. Today only common wasps seem to be around.

Late October 2013

A walk in Ravenstone Road Copse, part of Yardley Chase, last week produced only a few flies. Several small craneflies were disturbed from the ride edges and turned out to be Tipula pagana, one of the subgenus Savtshenkia. I then caught two more in my moth trap in the garden in Rothwell the next day. 

There were some spectacular fungi growing in the wood and several fungus gnats were seen disappearing under the caps of honey fungus Armillaria mellea. They kept flying into grass tussocks or onto a tree trunk and were hard to observe. I did manage to net some. They all turned out to be Mycetophila britannica males. There was also one lesser house fly Fannia parva in the net.

Honey Fungus Armillaria mellea

Mycetophila britannica on Honey Fungus (c) Jeff Blincow

A walk round my garden today only produced the one species of hoverfly, Helophilus pendulus. These are regularly sitting on the leaves of a variegated sedge at the side of my pond. I suspect the males are waiting for females as their larvae develop as rat-tailed maggots in the pond.

Helophilus pendulus taken at Boddington Meadow last year

Early October

Most of September I was either in France & Germany or down with a heavy cold so I have not much to report.  I have done no field work on flies but have been helping with the Nene Valley Ecology Group's water invertebrate surveys and found several new beetles for me.

Anyway, back to flies. At the beginning of September my garden in Rothwell still held several Tachina fera, visiting marjoram flowers. Marjoram is a must have if you want to attract insects to your garden. I also noted Eristalis tenax, E. Pertinax, E. Arbustorum, Myathropa florea, Syritta pipiens, Eupeodes luniger and Helophilus pendulus hoverflies. Helophilus pendulus is still around the pond in early October.

On warm Autumn days like today one of the best ways to find nectaring insects is to look for some flowering ivy. I shall be searching the hedgerows and wood edges for suitable ivy patches over the next few days. There has been a large emergence of the long-palped cranefly Tipula paludosa and many are coming into the house. Later this month, its close relative Tipula subcunctans should be about.

Whilst trying to shake off my cold, I was able to catch up with identification of some flies that I took earlier this year. The Dipterists Forum held its Spring weekend field meeting in the Rockingham Forest area and I collected quite a few flies that I am still working through. The weather was poor for two of the three days so finding flies was hard work but I did add some new species for me. Titchmarsh Wood, part of the Souther Wood complex turned up Empis nigritarsis and the parasitic fly Lypha dubia.  I still have more to do so am hoping for other new finds.

Late August 2013

Since my last blog about mimicry in hoverflies an example of its ability to confuse cropped up on BBC 2's recent Horizon science programme on what's happening to our bees. At one point it showed a "honey bee" which was, in fact, the hoverfly Eristalis tenax.  Oh dear! This is not the only example of hoverfly photos being used to represent bees. I remember browsing in a bookshop a few years ago and picked up a book entitled something like "Bees of the World" and the dust jacket photo was of an Eristalis hoverfly. It did not encourage me to regard the book as an authorative reference work.

Usually in late July and August Britain receives a large number of migratory hoverflies along with butterflies, moths and dragonflies. It is usually signalled by a sudden increase in the marmalade hoverfly Episyrphus balteatus and a few Scaeva pyrastri accompanying them. Although there have been plenty of Silver Y moths and Clouded Yellow butterflies about, I have not seen a great deal of evidence of a major hoverfly influx. There were plenty of E. balteatus about but I was seeing them in tens on most sites, not hundreds, and I have seen only one Scaeva pyrastri. There have been one or two sightings of Eupeodes latifasciatus, which may be a partial migrant, but overall I do not get the impression of a significant hoverfly migration in this area. I do not know if this is a general view across the country. I might raise the question on the Hoverfly Recording Scheme website.

One hoverfly that did catch my attention this week was of a Syrphus type with more black on the legs, particularly the hind femora, than with the usual species. Also the yellow bands on the tergites seemed to dip down towards the outer edges.  I managed to poot it off a bramble and took it home to identify. It turned out to be Didea intermedia, possibly a first for Northants. I took it in a wood with several blocks of conifer plantation. It was easy to key out and I was able to confirm it by comparing it with a couple of specimens I had from Speyside, its main stronghold in Britain. Interestingly, the following day someone reported one from Gloucestershire, a first for that county too. Also in the wood was Sphegina clunipes, a species for which we receive few records, although it is widespread in Britain. I rarely bother with conifer plantations but sometimes it is worth looking at different habitats, no matter how unpromising they may appear.

Hoverfly Mimicry

Over the past month there have been quite few hoverflies that mimic bees or wasps about. Some of the mimicry is really good and some less convincing, at least to our eyes. Harmless species that have evolved to look like potentially dangerous or distasteful species are examples of Batesian mimicry. There are many examples in the hoverfly family. Here are some photos that I have taken over the past  few weeks.

Volucella bombylans mimics several bumblebees. This photo shows the red-tailed form which mimics Bombus lapidarius or Bombus rupestris. V. Bombylans also has a white-tailed form mimicing  Bombus lucorum or Bombus hortorum.

Eristalis pertinax mimicing a honey bee.

Myathropa florea mimicing a social wasp

Xylota segnis - is this mimicing a solitary wasp?

Chrysotoxum festivum mimicing a social wasp

There are many others I could have shown. Look carefully at the "bees" and "wasps" and you might be surprised at how many turn out to be hoverflies or indeed other families of fly (Conopidae for example) or other insects such as wasp beetles.

A spectacular cranefly and a deadly fungus

When I collected the catch of flies from the moth traps at Pitsford last week, Mischa Furfaro, one of the wardens on the reserve, gave me an unusual-looking cranefly that she had found on a tree trunk whilst checking the nest boxes. The cranefly turned out to be Ctenophora pectinicornis. This species is one of three British species of cranefly that mimic large ichneumons or wood wasps. They are all rather scarce. Apart from their smart black and yellow colouration, the males are distinctive because of their peculiar pectinate antennae, as can be seen in the photo below.

These craneflies breed in dead wood, typically high in trees and so tend to be associated with ancient woodland. The male that Mischa found may well have been searching for a female around the nest box.

On Sunday I visited a local wood and swept the fly shown below from the ride-side vegetation. It was dead and furry-looking growth was coming out from around the abdominal segments. This fly had been infected by an entomopathogenic fungus. There are several species of fungus that kill flies and other insects. Typically a spore is picked up on the surface of the insect. The spore then develops hyphal threads which eventually penetrate the insect's exoskeleton and continue to develop inside the insect. Toxins released by the fungus kill the insect. The fungus then produces its fruiting bodies on the outer surface of the insect and the next generation's spores are released. It normally requires conditions of high humidity for this cycle to complete. There is currently scientific research being undertaken to see if this could be developed as a biological control for certain pest fly species, including mosquitoes.

Portevinia maculata and Ramsons

At this time of the year a number of woodlands contain carpets of ramsons Allium ursinum, which scent the air with garlic. At the beginning of June I visited two such woods at Fawsley as part of the Wildlife Trust's Bioblitz. I was particularly keen to find the hoverfly that is associated with ramsons, Portevinia maculata. It is not a particularly striking species, with its grey dusted spots but it is not frequently recorded in Northants. According to "The Flora of Northamptonshire and the Soke of Peterborough", recently compiled by Gill Gent and Rob Wilson, ramsons occur in about 75 tetrads in Northants. However I only have records of P. maculata from three.  It is almost certainly present in most sites where there is an extensive and well established population of ramsons so must be well under-recorded in the county. The fly's association with ramsons is strong. It's larvae are miners of the bulbs of ramsons and adults can be easily found when the ramsons is in flower and the weather is warm enough for the hoverflies to seek nectar. I have attached a couple of photos in the hope that more records will be made. It is easily recognised from the grey spots on the abdomen, so long as you make sure it is a hoverfly you are looking at. Similar-looking higher flies will have bristly bodies, whereas this hoverfly does not have prominent bristles and shows the "false margin" on the wings created by the two outer cross-veins running parallel to the outer hind edge.

Portevinia maculata on ramsons flowers.

Portevinia maculata showing grey dusted abdominal spots and the "false margin" on the outer edge of the wing, seen more easily in the lower wing.

Ramsons in a wood in Northants in early June.

Mid/late May 2013

The frequently cool, cloudy weather and wet days has not been ideal for hoverflies and other fly families that like to sun bask or take nectar. Craneflies are less badly affected by such weather and the Spring species have been the major component of my forays of the past three weeks. In particular, our local woods have held many of the short-palped cranefly Limonia nubeculosa. This is one of the most easily identified of our craneflies. It is medium sized, with mottled wings and three dark rings on each of its yellow femurs. These three rings are unique in the British cranefly fauna. The large grey long-palped cranefly Tipula oleracea is also very common at present. Another large long-palped cranefly that I am finding at most woodland sites is Tipula varipennis. This has mottled wings, whereas T. oleracea has the typical wing pattern of the Tipula sub-genus: a dark leading edge with a whitish parallel stripe behind. The other really common cranefly about at the moment is the smallish, black hairy-eyed cranefly Tricyphona immaculata.

On the odd warmer days, hoverflies have been more easy to find and more species have been emerging. In the early May blog I mentioned the appearance of the 'Heineken Hoverfly' Rhingia campestris. Its close relative R. rostrata is also on the wing now in our ancient woodlands. The two species can be separated in the field if good close views of them are obtained. On the wing it is very difficult to separate them. The former species has narrow black edges to its abdominal segments (tergites), brown to black legs and a bronzy top to the thorax, whereas R. rostrata has a pure orange abdomen, more orange legs and a bluish grey top to the thorax. This latter species has only been found in Northants for the past few years. It was formerly confined to the South and West of Britain but has been expanding its range North and East. It is now frequent in our local woods, although I have yet to see it in my garden.

                     Rhingia rostrata showing bluish-grey thorax, orange abdomen and legs and long "snout"

Rhingia campestris showing more bronzy thorax, darker legs, black edges to the tergites and slightly longer "snout".

The most interesting hoverfly for me so far has been Criorhina berberina, a very good bumble bee mimic, which I saw feeding on wayfaring tree flowers in one of the Yardley Chase woods. These hoverflies have larvae that feed in rotting tree roots and are associated with ancient woodlands.

Now that the hawthorn is coming out, the St Mark's fly Bibio marci is becoming frequent. This largish black fly can be seen in swarms around the flowers of hawthorn. It gets its name from coming on the wing around St Mark's Day, 25th April. However the late Spring has delayed its appearance and I did not see one until 15th May. Another frequent visitor to hawthorn is the empid fly Empis tessellata. This is a large empid with a long, straight, downward-pointing proboscis, dark in colour with yellowish bases to its wings. It is a predator of other flies but can also been seen drinking nectar at a variety of flowers. I have seen one capture a Syrphus hoverfly and kill it.

                                         
                                                     Empis tessellata

Another very common empid at present is the smaller, yellow Empis trigramma. It gets its scientific specific name from the three dark stripes on top of its thorax. However, that is not enough to identify the species as there is another very similar empid also on the wing E. punctata. The two are separated from each other by the arrangement of bristles on top of the thorax. I have recorded both locally in the last couple of weeks.

Early May 2013

The warmer weather has brought out more blossom and the hoverflies are coming out with them. Around the blackthorn flowers, male Eristalis pertinax are holding territories. There are also many Eristalis intricaria about, more than I have noted in previous years at this time of the season. This is a dark bumblebee mimic.

Last Saturday I noted the first Epistrophe eligans of the year in Old Sulehay forest. This species is one of the iconic Spring hoverflies. Nationally, its appearance has been getting earlier in the year, presumably because of climatic warming, so I wondered if the long cold Winter had delayed its appearance this year. Looking back over the past 10 years of my observations, the first dates for me in Northants were:
2003 11th May
2004 no record
2005 17th May
2006 no record
2007 22nd April
2008 26th April
2009 26th April
2010 27th April
2011 07th April
2012 10th May
2013 04th May.
So it was slightly late but by no means the latest I have recorded it.

Epistrophe eligans, showing the broad yellow marks on the second abdominal segment, narrower ones on the third and no yellow on the fourth.

Another typical Spring species is Leucozona lucorum. I saw my first for the year on 4th May near Yardley Hastings.

Leucozona lucorum, showing the bright white marks on the base of the abdomen contrasting with the black apex. L. lucorum has a yellow scutellum, whereas the similarly coloured Volucella pellucens has a black scutellum.

In the local woods and even in my garden the "Heineken Hoverfly" Rhingia campestris is also on the wing.

We are now seeing the first of the Spring craneflies emerging, with the large long-palped cranefly Tipula oleracea being taken at the Pitsford Reserve's moth traps.

End April 2013

The warmer weather in the middle to end of the week has produced more activity. In particular bee-flies have been numerous at several sites I have visited over the past few days. My first record of our commonest bee-fly, the dark-edged bee-fly Bombylius major was on 20th April in my garden. What a contrast with last year, when my first garden record was on 25th March! Locally, we only have one species of bee-fly, but there are 9 British species, although most are rare. One other, the dotted bee-fly Bombylius discolor could turn up locally. It has been recorded in Warwickshire. It is easily recognised as a bee-fly with spots all over its wings, hence its common name. It is more likely to be found in areas where there is sandy or chalky soil where its mining bee host can be found.

Two images of the dark-edged bee-fly Bombylius major. The upper image shows one hovering whilst drinking nectar from a wood anemone flower in Stoke Wood, whilst the lower shows one at rest in my garden. The dark front edge of the wing, which gives it its common name, is clearly visible in both photos.

The fly is a larval parasitoid of the larvae of some solitary bees. The female fly gathers sand into a special chamber in her abdomen where she mixes it with her eggs. She then finds an area of bare ground where the host is likely to nest and, whilst hovering over it, she flicks the egg/sand mixture at the ground. When the fly larva emerges it enters the nest and finds an open bee larval cell and enters it. The fly larva waits for the bee larva to grow then it attaches itself to it and feeds on the bee larva's body fluids, killing it in the process.

Apart from bee-flies, there have been a few species of hoverfly about locally. This past week I have seen four species of Eristalis - pertinax, tenax, arbustorum and intricarius. The last one is a blackish bumble bee mimic, whereas the others are more like drone honey bees. Also noted have been Syrphus torvus, Platycheirus albimanus, Melanostoma scalare, Cheilosia pagana and Cheilosia chrysocoma. This last species is not at all common. It flies early in the year, which may mean that it is missed. I usually record it between mid April and mid May. It is a very attractive fly, with rich foxy-red hair over its body. It is usually found sitting on dead leaves or branches on the ground in a sunny spot. The photo below was taken by Keith Walkling in a local wood.

Cheilosia chrysocoma male photographed by Keith Walkling.

If anyone thinks they have seen this species locally I would be interested to know. A photo or voucher specimen of it would be needed to confirm the record.

Mid April 2013

The milder weather over the weekend should have stimulated some hoverfly activity. I spent the weekend helping with wetland invertebrate monitoring in the Nene valley, so did not get chance to hunt for hoverflies. However today I had a good look round the garden - nothing found, so I visited Stoke Wood in the afternoon. Although there was a stiff breeze blowing, the main ride was sheltered and catching the sun when it appeared.  There were plenty of primroses and wood anemones to provide nectar and some sallows were in flower too. I did not see a single fly visiting flowers! However, I did find Eristalis tenax, the drone fly, sunning on the ride edge. The only other hoverfly I found was Ferdinandea cuprea which was sitting on a newly cut stump. This species is associated with ancient woodlands, where its larvae live in sap runs. It is not a frequent visitor to flowers and is more often seen on tree trunks or logs.

Eristalis tenax, the drone fly

Ferdinandea cuprea

Apart from the two hoverflies, there were a few common yellow dungflies Scathophaga stercoraria and the odd anthomyid fly. Other wildlife included a common toad, a peacock butterfly, singing chiffchaff and green woodpecker. Over the field on the track into the wood a single buzzard circled and three lapwings flew across.

With only four species of hoverfly to date, I felt that it had been a slow start to the season but, looking back to last year, when we had a good start to the Spring, I had only seen 4 species by mid April then. I had received records of another 3 species from other people, whereas so far this year I have no other hoverfly records. So, despite the cold weather, things are not so bad.

Early April 2013

I have been away in Sri Lanka for a couple of weeks and coming back to snow was a bit of a shock. It is still too cold for much insect activity but there are a few things to report.

Firstly, the Cranefly Identification Workshop, run by John Kramer at Pitsford Water's Holcot Lodge went well with 11 attendees. John gave a well illustrated introductory talk to the cranefly families before we got stuck in to the keys, using John's reference collection. It was also an opportunity for John to get some feedback on these draft keys so they can be revised for publication. Updates will be posted on the Dipterists Forum website from time to time.

Secondly, Roger Morris and Stuart Ball's new WildGuide to British Hoverflies arrived through the post. I am very impressed. The photos illustrating key identification features are generally first class. I am sure it will convert many people into identifying hoverflies. There is much detail in the well-illustrated text that will be valuable not only to beginners but to experienced dipterists as well. It is particularly good at helping with field identification.  It does not replace Stubbs and Falk's British Hoverflies, which is much more comprehensive, but it does complement it very well.

On the subject of Hoverflies, the Wildlife Trust for Beds, Cambs and Northants will be continuing its Hoverwatch monitoring work at Old Sulehay this year. If anyone is interested then do get in touch with me or Henry Stanier at the Trust's Cambourne office. We are also looking out for people who would like to set up a constant effort hoverfly monitoring site on any of the Trust's reserves. This is basically the same as the "Big Hoverfly Watch", described by Roger Morris in the Bulletin of the Dipterists Forum. The only difference is that for the Trust sites is that we want a visit in July as well as May and June. The same survey can be used for both projects. In preparation for the Hoverwatch and constant effort projects I shall be running a one day workshop at Ring Haw field centre on April 27th.. If anyone is interested in attending please contact me or Henry Stanier.

I have not found any flies of interest locally, but Mike Killeby has been beating dead leaves and branches of pines on our forays on the Compton Estate. He has passed the flies on to me for identification. The most interesting were 3 picture-winged flies found Denton Wood on 14th March. These keyed out to Tephritis matricariae. A number of these gall-forming flies over-winter as adults and emerge in the Spring to lay their eggs on the developing host plants.

Yesterday Mike gave me a window gnat, which keys out to be a male Sylvicola cinctus. This is probably the most common member of the genus, although many books illustrate what is claimed to be Sylvicola fenestralis. This latter species is not common and has been misidentified in a number of publications. Indeed my attention was drawn to it by Jon Cole when I listed S. fenestralis in one of the newsletters. He sent me a paper showing the differences in genitalia. I have re-examined my specimens using this paper and they have all proven to be S. cinctus. I urge anyone who thinks they have S. fenestralis to double check. For females it is necessary to exert the genitalia a little. With dried specimens this means relaxing. I put the specimen in a jar with some damp tissue in the bottom, the specimen should not be in contact with the damp paper. Left tightly sealed overnight, the specimen was quite flexible and I was able to work on it without bits shattering all over the place.

Early Hoverfly

The warm weather at the beginning of the week seemed to wake up a few insects and I have heard of several sightings of butterflies and bees. However, I had to go to a funeral in Suffolk on Tuesday so missed the best of the weather. Back at home on Wednesday I noticed a fly on the inside of the window. On taking a closer look I realised it was a hoverfly and it looked superficially like a Melanostoma. Anyway, I caught it and looked at it yesterday. It was a male and had rounded front tibia and tarsi and yellow, heavily dusted spots on the abdomen. I went through the Melanostoma key and it failed on abdomen shape and dusting on the frons. It also did not look right, with a fairly inflated frons and face. Going through the Platycheirus key it failed again. However, I remembered that Platycheirus ambiguus is an early species and has rounded front tibia and tarsi, so I tried that part of the key (ie abdomen with silver/bronze spots not yellow spots). It keyed out perfectly. I then checked in van Veen's key to the Northwest European hoverflies and again it keyed out. In this key it does say that the abdominal spots can be dusty yellow. One of the characteristic features of this species (and shared with only one other NW European hoverfly) is the curled bristly hair at the apex of the front femur and that was present on my specimen to confirm it. Platycheirus ambiguus is not well recorded, probably because of its early flight season. It is best searched for flying high around blackthorn when it is in flower. Peak records are from around the end of April, so this is still an exceptionally early record. I have found it locally around blackthorn and flowering fruit trees in late April so keep a look out for it.

That species has brought my garden total for hoverflies to 34. Must try harder!

With the change back to cold, damp weather and colder weather forecast, I suspect there will be no more hoverflies around for a while. However, the pussy willow buds are just starting to open in sheltered spots and they should provide nectar and pollen for the first few hoverflies of the season. An early hoverfly to look out for at sallow blossom is Cheilosia grossa. I have no records of this species, although it probably occurs locally. Its tendency to fly high and early in the season probably means it is overlooked. It is apparently more easily detected as a larva developing in the base of thistle stems later in the season. Stuart Ball has produced a guide to finding it and Cheilosia albipila. The guide can be downloaded from the Dipterists Forum website at:
http://www.dipteristsforum.org.uk/t104-Recording-Cheilosia-larvae-from-thistles.html

Early March

When I was making artificial rot holes in the stumps at Pitsford Reservoir, I took a winter gnat from the moth trap. It was a female and I struggled to identify it. However, at the Dipterists Forum workshop, I asked Alan Stubbs if he could take a look and he immediately identified it as Trichocera regelationis. This is a common species but not recorded at Pitsford before. Alan explained the identification features. The Dipterists Forum workshops and field meetings are great opportunities to pick up tips from the experts.

In May the DF will be holding a Spring field meeting in the Rockingham Forest area where we will have the opportunity to visit some really good sites. If anyone is interested in coming along contact me or Roger Morris and check out the DF website.

 On Sunday, I visited Pitsford but it was very quiet. However, I did check out the artificial rot holes in water bottles that I had put up a few years ago. One of the bottles had a rat-tailed maggot, the larva of a hoverfly from the Eristalini tribe. It is probably Myathropa florea. One of the bottles was too dry for use by flies but the others looked to be suitable.

 There are a few flies starting to be active now the weather is warming up. Anthomyids are among the first Spring flies but I find them very tricky. I was advised at the DF workshop to only attempt males and the easiest approach is to expose the genitalia and compare them to the diagrams in Ackland's key. The key itself can then be used to confirm identification. On that basis I shall try to record some of these species this year.

 The UK Hoverfly Recording Scheme's big hoverwatch project that attempts to use constant effort recording to track changes in hoverfly numbers and distribution got off to a soggy start last year. Let's hope we have better conditions this year. The Wildlife Trust also want to use the same technique on some of their reserves so it is an opportunity to contribute to two projects with one survey if a Trust reserve is chosen as the site. Details can be obtained from Roger Morris on the Hoverfly Recording Scheme's website or from me or Henry Stanier for the Wildlife Trust's project.

Creating Dead Wood Habitat

Many species of fly, as well as beetle, wasp, bee and moth breed in dead or rotting wood. Many of these saproxylic insects are declining. Continuous availability of suitable habitat is required for many of these insects. Clear felling of woodlands often leads to a break in availability of wood of suitable size, age and degree of decay. Added to this, tidying woods to remove dead branches and trunks to reduce risk of fire or of injury further reduces suitable habitat. Many woodland managers are recognising this and are starting to be more sensitive to saproxylic insect needs. In many cases dead wood piles and branches are left on the ground as habitats. However, many species require standing dead wood or living wood with rot holes. Last week, with help from the wardens at Pitsford, I had a go at trying to create some habitat in stumps of felled trees. This was done by chiselling out a depression in the cut stump and filling the depression with the wood chips. Eventually these will fill with water and start to rot. Here are a couple of photos of the stumps:

It will take some time before anything happens but I shall keep an eye on them and see what develops. I may also try to make some more in taller stumps as these will eventually simulate standing dead wood.

I have previously had some success with artifical rot holes made from empty plastic drinks bottles, with a hole cut in the side and filled with rotting vegetation and water. The woodland hoverfly, Myathropa florea, has successfully bred in these. It is important that the filling does not dry out.

                                           Myathropa florea

Late February

Last weekend I attended the Dipterists Forum identification workshop covering the Heleomyzid and Lauxanid flies. It also covered one or two other families of acalypterate flies with spines on the costal vein of the wing. It was a very useful session and good to catch up with friends I have made at previous workshops and field meetings.

I was able to identify a few specimens that I had taken locally, including the Heleomyzid that I found at Yardley Chase a couple of weeks ago. This was Tephrochlamys tarsalis, a female. A number of Heleomyzids are active in winter, which probably means they are under-recorded as not many dipterists are!

I was also able to look at the new hoverfly book by Roger Morris and Stuart Ball. They had been given a pre-publication copy. It looks very good, with excellent photos and should help with field identification. It is due to arrive in the UK on 5th March and should be available shortly after that. Dipterists Forum members should be able to get it at a discount.

Heleomyzid fly photo taken with an iPad through the eyepiece of a microscope.

My first hoverfly of the season

I have been spending the day in the garden, trying to prune some shrubs and clear back some ivy that is threatening to engulf the borders. I don't want to get rid of the ivy as it is such a good plant for wildlife but it does need to be kept on a tight leash.

Anyway, the sun was bright and the more sheltered parts of the garden felt quite warm. I saw a peacock butterfly fluttering in the sun so had high hopes of a hoverfly. Examination of the leaves of Bergenia revealed a single drone fly Eristalis tenax. This is usually the first hoverfly I see in the garden each year and is usually on the Bergenia. I think the combination of early flowers and a sheltered sunny position make it a very attractive spot.  I expect the marmalade hoverfly, Episyrphus balteatus will be the next hoverfly species to occur, as it too overwinters as an adult.

On Thursday morning I joined the Wild Bunch for our usual foray into Yardley Chase. The highlights were woodcock and a lesser spotted woodpecker. This is the first I have seen for over 10 years in the county. I had high hopes of finding a hoverfly as there were some good sunny intervals. One promising area was a large manure heap, which should have provided a warm microclimate for flies. Sure enough there were several midges and, on close examination, I found some higher flies. I did not have a net and did not fancy pooting off manure so catching any was a problem. I did manage to get a tube over one fly and bring it home for identification. It is a heleomyzid fly. These characteristically have prominent spines along the wing's costal vein. At present I do not have a key to species but luckily next weekend's Dipterists Forum workshop is covering Heleomyzidae and Lauxanidae so I should be able to identify it to species. I have one or two saved heleomyzids and lauxanids to sort out so may be able to add some more records.

I see that Roger Morris in his blog (see Links) is trying to encourage keen wildlife photographers to photograph hoverflies in their gardens so that he can try to identify them to see what occurs. He notes that Jenny Owen had 90 species of hoverfly in her garden over the years she did her recording. I must see how many I have found so far.

Early February 2013

The cold weather has meant I have not made much effort to look for flies, rather I have been trying to catch up with identifying material I took at the Dipterists Forum's Summer field meeting at Speyside. I have found several species of hoverfly that I have rarely, if ever seen before. I have a lot material to work through before the season starts.

 I have only recorded two species of fly in Northants so far this year. On the last day of January, beating an evergreen bush at Castle Ashby yielded the fungus gnat Mycetophila ocellus.

Today I visited Pitsford Reservoir and spent some time looking at dead wood and searching leaf litter. The best thing I found were 3 woodcock but I did find one fly. It was in leaf litter very close to a pile of deer droppings. Appropriately enough it turned out to be a lesser dung fly, Sphaeroceridae, a female  Crumomyia fimentaria. This is a widespread species but, as few people record them, it is a new record for the reserve.

John O'Sullivan, the Bedfordshire recorder for hoverflies tells me that he has had a few records of the marmalade hoverfly Episyrphus balteatus and the drone fly Eristalis tenax. So there are hoverflies about still.

Diptera Group Newsletter Added

I have pasted a copy of the newsletter into the Newsletter pages. I am sorry about the uppercase format but that happens when the page is displayed. If I go to edit it the text is a normal mixture of upper and lower case. I have reported it to Google.

With a forecast thaw on its way maybe there will be a few more insects to look out for.

Late December

Well, I had hoped to find quite a few flies during the month but poor weather and other commitments have kept the numbers down. Apart from the flies I collected at Denton Wood on the 6th and the winter gnat on the 8th, the only fly I have to report is a hoverfly, Eristalis tenax, female from Castle Ashby on 18th.

Tony White reported a tachinid, Macquartia grisea from Byfield Pocket Park.

I have not had chance to check all the Denton Wood flies yet but have found a Chloropid and a Mycetophilid of the genus Exechia. I do not have keys to take them any further.