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July 2018  wildlife, from the Somerset Levels

July 24th 2018. The next informal meeting of our invertebrate group gathered this morning at Worley Hill, the private reserve run by Millfield School on the Poldens. This is a great favourite of ours, and has been an annual event over a good few years, thanks to the kind efforts of Shane, who is in charge of this splendid site. Robert, who we had not seen for some while, managed to join us, thanks to a friend's transport. We can only hope that this is the first or more in the future, as he is a great practical naturalist. Chris, Nigel, John and I joined Shane, completing those present. Although the site has been rainless, like to so many other parts, there turned out to be a variety of insects, though they were not prolific. - it is likely that many more were hiding from the intense heat that has been with us for weeks now. The temperature up in the hills was around 27°, rising to over 30° on the way home across the moors. A great deal of work has been carried out on the site over many years, helped by work-parties from the school, and other volunteers, as well as the hard-working staff. The place has been transformed by removal of conifers, periodic pollarding to rejuvenate trees, cutting grass and clearing areas to allow growth of wild flowers. The numbers of species are recorded in an annual report and have reached impressive numbers. Part of the site is a tumbling area of semi-loose soil, typical of the edges of many Polden hills. These have their own special wildlife and plants able to deal with periodically shifting but baked soil. From our particular view, we have always counted it a particularly rich area for grasshoppers, crickets and ants. Robert has been of special help in identifying and searching for these groups, with the aid of his bat-detector - though neither were in particular evidence on this occasion. Perhaps the most interesting find was a sap-run on a quite small oak-tree, Quercus spp. No-one appeared to have come across this phenomenon on an oak previously, so it was of special interest. Several Hornets Vespa crabro were circling it, then dapping down to sip the sap. Some of our people were specially interested in Lepidoptera. Among those spotted were Ringlets Aphantopus hyperantus, Small heath Coenonympha pamphilus, Brimstone Gonepteryx rhamni, Common blue Polyommatus icarus, Brown argus and Silver-washed fritillary, the latter well-worn specimens.

Brown argus Aricia agestis


Silver-washed fritillary Argynnis paphis

Bumblebees were present in small numbers, but of various species. Bombus pascuorum, B. terrestris, B. jonellus were the most obvious.


bumblebee Bombus pascuorum w


bumblebee Bombus pascuorum w


bumblebee Bombus jonellus

A couple of species of cuckoo bumblebees completed the tally, caught gloriously in flight from one flower to another - usually rather lazy bees.


cuckoo-bumblebee Bombus bohemicus


cuckoo-bumblebee Bombus sylvestris

The only solitary wasp was a beautiful and tiny metallic Lasioglossum morio.

mining bee Lasioglossum morio

As we walked up to the open area, I sat down for a period to watch a crumbling miniature cliff with various drilled holes. A few ants appeared, but were too quick for identification, then a small spider-hunter wasp, probably Priocnemis spp., which I did manage to photograph, as it paused only for a micro-second.


spider-hunter wasp 

A few hoverflies were present, mostly Eristalis spp. but I enjoyed photographing tiny Syritta pipiens particularly. Their colours, shape and high-speed flight combined well with the bright colours of the flowers they visited.

hoverfly Syritta pipiens f

hoverfly Syritta pipiens f

hoverfly Syritta pipiens m

Finaly, following much the same theme, a tachinid fly (if anyone is able to identify it I would be grateful for a note - subsequently named by Robert, thanks) posed beautifully on a flower, showing off the intricacies of its bristles and shape.

tachinid fly Eriothrix rufomaculata f

July 21st 2018. Continuing concentration on a freshly-delivering sector of the logs, I spent a most enjoyable time watching life come back to the flats. While leafcutter bees continued to be the most obvious inhabitants, bulky, busy, going in and out of nests and potential nests; wasps started appearing in greater numbers than previously, appearing dark, square insects until they opened their wings, then their brilliant black and white abdomens appeared - Ectemnius species in all their glory.

digger wasp Ectemnius continuus f

digger wasp Ectemnius continuus f

digger wasp Ectemnius lapidarius f

digger wasp Ectemnius lapidarius f

Later, one or two tiny chalcids appeared, exploring the nest areas. Pteromalus album is a parasitoid of Megachile centuncularis and M. willughbiella, both of which leafcutter bees have figured in the logs over a period of years.

chalcid Pteromalus apum f

But the stars of the show, as they are always at this time of year, were leafcutter bees. Two species were hard at work within an inch of each other. They arrived carrying leaves, then wriggled and twisted until everything was perfect. The first two are Megachile centuncularis. The full-length unicoloured pollen brush beneath the abdomen is clearly seen here.

leafcutter bee Megachile centuncularis f

leafcutter bee Megachile centuncularis f

The other two are M. versicolor showing a red-gold pollen brush ending with a section in black.

leafcutter bee Megachile versicolor f

leafcutter bee Megachile versicolor f

July 19th 2018. Following on from photographing the leafcutter bees at Steart, I felt I needed somehow to increase the magnification of the picture in the camera so as to increase the distance from the insects. Taking insects at ground level brings with it need for a longer reach, if the picture is not always to be from above, often aesthetically poor. I can no longer get down on my knees or, if i do, cannot stay for long or get up without a great deal of effort, hence carrying around a rucksack with built-in stool, as used by fishermen. This works well but you find yourself further away, because of the acute angle. You end up leaning forward more and more, putting strain on all the muscles. I decided there must be a way round this; increase the focal length of the lens in use. With macro work, using f14 or f16 apertures and flash, there are not the problems of quality found with longer lenses used wide open with bird photography. My Sigma 150 macro lens was designed to work with an extender. So I located and bought a used Sigma EX DG 1.4 APO teleconverter and these are the results, tested out on the drilled logs, using built-in flash with the Rogue Safari extender in the shoe. This outfit has a working focal length of 315mm, compared with the previous 225mm (the Nikon D300 multiplies the focal length by 1.5) The whole outfit is still relatively light but ought to be used with a monopod. Autofocus seems to work as rapidly as it does without the converter. I think the results are amazing. It has the potential to improve many difficult photographic situations. I shall be using it in future for 'out-and-about' photography, leaving the D300 and conventional flash for work at the 'flats'. The flash extender takes it all in its stride and resolution is excellent. This bee flew in with a leaf segment tucked under its abdomen and may be seen here carrying it into its 'works', then frantically twisting and turning in its efforts to position it exactly - all at high speed.

leafcutter bee, Megachile versicolor f

leafcutter bee, Megachile versicolor f

The above pictures were taken while watching a particular insect carrying out the final stages of its whole-nest construction. The identification is quite clear, with the gold and black pollen brush beneath the abdomen, though a faded, rather battered, older specimen. I went in for a cup of coffee; when I came out again, it was clear that the insect straddling the same area was not M versicolor f, instead, M. centuncularis m. At first, I imagined both species were females constructing cells in the same hole - not completely unknown, though there were many empty bamboos nearby. The male must have been a hopeful, trusting that it had come across a female of his own species. In fact there turned out to be both male and female at the bamboos. If I'm confused, what must they be?

leafcutter bee, Megachile centuncularis m

leafcutter bee, Megachile centuncularis f

July 15th 2018. After an earlier frustrated attempt, when I was unable to get through Bridgwater because of road problems, I managed to drive out to Steart Marshes again this afternoon. It was hot but, being on the coast there was  a fresh breeze, quite comfortable at 25° out on the grazing marshes. When I reached the area where the leafcutter bees had been previously, I thought they had all vanished, so sat down to wait, not really hoping for much. After a while the whining of their wings came over quite clearly and the insects were spotted dropping down to their burrows. I had brought a little fishing stool with me and sat on that for the next hour or so - a bad mistake, as my knees stiffened up completely by the end. I think the position was exacerbated by bending forward so much. The insects are small and, even with a 150mm lens, need to be close for a decent picture. Regardless of that, it was a most enjoyable period, though I was unable to spot any of the bees bringing in leaves. I suspect this particular batch were still drilling their burrows. I hope to come back later to complete the cycle. I had hoped to take pictures of the leafcutters in flight and was fortunate enough to catch a couple of good shots, in focus. Flight shots show the greatest detail, as the wings no longer obscure the abdomen.


leafcutter bee Megachile leachella f


leafcutter bee Megachile leachella f

I concentrated on watching one particular bee where I had reasonable, unobscured views of what was going on; for burrow construction is a lengthy and skilful process. The insect drops straight down onto the right spot, an apparently unmarked patch of loose sand, though others, including 'my' bee chose a point on the edge of or under a few stalks of herbage. She digs furiously, then backs out with a wriggling motion, bringing with her a patch of darker material, the deeper sand from within the burrow. She pushes this out for an inch or so and shoots back into the burrow. Every so often, she would emerge, look round and and take off, circling a couple of times before landing and resuming her labours. Was she getting stiff from her efforts? This bee continued the work all the time I was there, with intervals between emergences lengthening, as the depth became greater. The burrows must be really deep after all this effort.


leafcutter bee Megachile leachella f


leafcutter bee Megachile leachella f

Towards the end of my time, I noticed other insects flying quickly round the same area. Eventually one landed and I saw it was a small mason wasp. It was black, with yellow-banded abdomen and very distinctive orange legs, Ancistrocerus scoticus, another insect I had not come across previously. Clearly they were taking the same advantage of the suitable sand for digging nest holes. According to some accounts, they make their nests in holes in pebbles, these appeared to be digging in the sand in the same area as the leachella, while the excavated material can be seen beside them, darker and greyer in colour. They appeared small and slender, though their length is given as 8-12mm for females and 7-9mm for males. As males have pale yellow legs, these were definitely all females, but appeared smaller than that range. They could be victims of recent weather inhibiting growth in their earlier stages. It seems they are relatively common in coastal areas such as this; a pleasure to watch. There is a particular feeling about looking down on insects continuing their life so closely and intimately, apparently without worrying about your presence.


mason wasp Ancistrocerus scoticus f


mason wasp Ancistrocerus scoticus f

mason wasp Ancistrocerus scoticus f

July 10th 2018. This morning, our destination was Steart Marshes, run by the Wildfowl and Wetland Trust, who have done a marvellous job since it was inaugurated some years back. Seawalls were breached near Steart village to provide a totally new approach to controlling the coastal erosion, as well as providing marvellous opportunities for wildlife with the development of new salt and freshwater marshes. John, Nigel, Jan and Jim, met up at the car-park, notable for a most magnificent wild flower bed, which was a riot of colour, While there were insects, the area was also suffering from the universal reduction in their numbers. Nevertheless, we had a fascinating and rewarding day, with a great many photographs taken - too many for inclusion here. Our day ended in two parts, the first taking us out to Quantock Hide overlooking a wide stretch of fresh water and Otterhampton Marsh; the second taking us down to the grazing marsh, by the sea, north of the main car-park to a long-established parking area with good access to the coast. Quantock Hide gave us a particular treat, distant views of Avocets Recurvirostra avosetta, one of the adults with a couple of chicks. This would have been more enjoyable if the windows could have been opened on such a hot day. It seems they are waiting for some work on the latches - judging from the remarks book, this has ben ongoing for a long while. Though a fine bench outside served well for lunch. The poor Avocet mother suffered from continual harassment from Carrion crows Corvus corone corone, so it is unlikely these particular chicks will be reared to maturity. A larger colony is needed to protect youngsters. Most of our 'conventional' insects were found while returning to the park. One side of a hedge caught just the right amount of light and heat, and cameras were soon clicking. None were particularly unusual, but it was good to see the population building up. When we last came here a few years ago, the flowers were well on their way, but the insects had not yet caught up.     bumblebee Bombus lapidarius f

bumblebee Bombus pascuorum w


bumblebee Bombus pascuorum


mining bee Lasioglossum xanthopus f


solitary bee possible Melitta leporina f


darter Sympetrum spp. exuvia (empty larval case)


Ruddy darter Sympetrum sanguineum m


Meadow grasshopper Chorthippus parallelus

We drove up from the main park to a small layby which has been the main access to the sea for locals as long as can be remembered, popular with sea-watchers, dog-walkers and family outings. We walked across a scrappy grazing marsh, the plants much-diminished by the heat but home to numbers of Skylarks Alauda arvensis; such a welcome sight and sound, together with the beautiful blue flowers of the sea-lavender.


Common sea-lavender Limonius vulgare

The sea is separated from the marsh by a band of sand and shingle. Walking along this, we remarked on the loud whining/buzz all round us; then we spotted the reason. A colony of the smallest coastal leafcutter bees was all round us. We only realised it was these when we caught glimpses of fresh green sticking out round the tail and abdomen. Females were bringing in freshly cut circles of leaves under their abdomens to construct their cells beneath the sand. This sand is extremely fine, running like water when disturbed. In all except exceptional circumstances, it was impossibl to spot the entrances the moment they left, yet they navigated directly to these and plunged straight in - too quickly to photograph. The shots I obtained were all of females seen actually digging their holes.

leafcutter bee Megachile leachella f

leafcutter bee Megachile leachella f

leafcutter bee Megachile leachella f

It is a shame but there was no glimpse of a male. He has spectaculr green eyes in place of the females dark ones. I call it a colony, but they are solitary creatures; the explanation being that they all fancy the same bit of real estate. Realising all this prompted a more thorough search. John spotted an area of smooth sand where they had been flying in and dug down to see if he could locate a nest. He came up with a length of cells made from fresh green leaves, presumably with pollen and eggs, though this might be too early for the full load.

leafcutter bee Megachile leachella nest cells

Nigel then searched and found the source of the leaves - a large Dandelion Taraxacum spp. plant with circular holes in the leaves.

Leafcutter bee Megachile leachella circles taken from Dandelion

July 9th 2018. A fresher day, though it reached 31° again by mid-afrernoon. Later, when the sun had largely left the log insect nests, a few more creatures started to appear. Leafcutter bees continue their activity, now there are three closures on one log and they are visiting some large bamboos close by. Ectemnius continuus was observed entering a small hole, dragging a paralysed fly in with it, to provision its nest.

digger wasp Ectemnius continuus f

digger wasp Ectemnius continuus f

A Coelioxys cuckoo bee appeared briefly, vanishing into a hole where it appeared to stay. Leafcutter bees were in action once more, but this time of a different species.

leafcutter bee, Megachile centuncularis f

Garden flowers cover the base of the logs and a common small hoverfly was photographed nearby.

hoverfly Episyrphus balteatus m

hoverfly Episyrphus balteatus m

Not a bad half an hour or so after all!

July 7th 2018. It is extraordinary that there are no entries this month, from the end of the last, but not so in view of the  extremely un-British weather we have been having. We have been baking under high temperatures for weeks on end now, with constant blue skies and, for much of the period, extremely high humidity. For all of this time the thermometer has hovered between 28 and 31° by late afternoon - generally the hottest period. In this country we expect summer temperatures of 20° rising to around 24° in the better periods, and then only for a few days at a time. This period, and it is forecast to continue for some while, has left many older people gasping, seeking shelter inside or where they can. And it is not just people, but flowers and herbage have had little or no rain during all this time. Garden flowers are withering, all growth has stopped - roadside verges are flattened and straw-coloured. Insects have vanished from the garden, virtually nothing moving anywhere. My log trap-nests have given up the ghost, with nothing looking for nest sites with the exception of a few of the smaller black Crossocerus digger wasps. No Osmia mason bees have appeared. At the start, a few solitary wasps were seen but now, nothing. Bumblebees and most hoverflies have vanished and the only insects flying are some of the commoner butterflies. Down on the moors, even the flies have given up visitng the umbels and trackside flowers. General wisdom has said that heat really suits insects, the hotter the better, but clearly these are British-born insects used to our normal tempertures and finding these high ones too much, forcing them to shelter down below in the grass and herbage - if that is where they are? So, there has been little to report other than that the sound of garden mowers has vanished from the area. However, today, fresher with a gentle breeze, though still more than 28°, I went to look at the logs and there was movement sufficient to make me fetch the camera and a stool. A larger insect was exploring the biggest holes, only briefly seen as it shot into one, but I had better views on settling down in front of this activity. In addition to this sighting, one hole had been closed with pieces of fresh green leaf, a sign that nest cells had been prepared, stocked with pollen and eggs laid inside. Below, I have prepared a set of pictures sequences, showing what was seen. The first sighting was of a male Megachile hoping to catch a freshly emerged female and mate with her. They generally emerge well before the females to give the best chances for mating. They were leafcutter bees. These insects prepare holes in wood, even using flowerpots with compost inside, and build a series of nest-cells using circular pieces cut out of rose or other suitable leaves. They fly in with these tucked under their abdomens, carry them into the hole, glue them into shape before loading them with pollen and laying an egg in each. The pollen arrives in an unconventional manner. The insect uses its legs to shovel up this pollen from the flower and loads it into the stiff hairs of the pollen brush located beneath the abdomen. It is a fascinating process, rapid and efficient.

leafcutter bee, Megachile versicolor m - waiting for the females


leafcutter bee, Megachile versicolor m - landing

leafcutter bee, Megachile versicolor f - exploring

leafcutter bee, Megachile versicolor f - making the cell

leafcutter bee, Megachile versicolor - the closure


 

hoverfly Episyrphus balteatus m

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