Thursday, 29 June 2017

Invertebrates, June 2017

June was a generally a very dry month which included a two week spell of very hot weather, with temperatures reaching 30'C on several occasions in the middle of the month. At times it was almost too hot for invertebrates, and during the hotest periods there was clearly a midday lull in hoverflies in particular.

It was the month that the impressive bumblebee mimic hoverfly Volucella bombylans appeared in numbers. My first of the year was at Pennington Flash, but soon they were a regular feature everywhere. Like Merodon equestris, this species can mimic more than one species of bumblebee. The form in these photos resembles Bombus lucorum, the white-tailed bumblebee. Interestingly, the larvae even live in the nests of bumblebees, feeding on the debris at the bottom of the nest.

This is also Volucella bombylans, of the mainly black form with a red tail which resembles Bombus lapidarius, red-tailed bumblebee.

Amongst the many highlights in June, finding the Currant clearwing moth Synanthedon tipuliformis on currant bushes in my back garden must rank amongst the best. Clearwing moths are day flying and mimic wasps. They are often thought to be best seen by the use of pheromones which attract the males, but although I have used lures to see these insects in the past, I have also seen at least three species of clearwing simply by looking in suitable habitat as I did in this case.

Currant clearwing with a currant!

Silver-studded blues Plebejus argus were out in their hundreds on the Great Orme, Llandudno in the middle of the month, these two males were on common rockrose.

The Volucella hoverflies are amongst the largest and most impressive in the UK, this is the largest of all, the hornet mimic Volucella zonaria, photographed on bramble in Aylesbury, Buckinghamshire.

Xanthogramma pedissequum, Arnside Knott. A wasp mimic hoverfly.

Ferdinandea cuprea. This actually looks like a fly mimic hoverfly, but I can't think why a hoverfly (which is just a type of fly anyway) would want to mimic a fly.

Scaeva pyrastri is a migrant hoverfly which like the red admiral and painted lady butterflies is present each year in the UK in variable numbers. This individual was photographed at Burton Mere Wetlands. Note the unusually bulging frons which is a feature of this species.

Volucella pellucens, great pied hoverfly was recorded at many sites in June.

Chrysotoxum arcuatum, another wasp mimic hoverfly at Arnside Knott. This is one of a group of five hoverflies which are difficult to seperate in the field. However on range alone four of the five can be eliminated, since they are more southerly species. Also a feature of Chrysotoxum arcuatum is that the 3rd antennal segment is longer than the first two combined, a feature which can clearly be seen in this photo.

Another one of the difficult five, this is Chrysotoxum cautum photographed in Aylesbury. Note the differences in antennal segmants to the previous hoverfly, with the third antennal segmant shorter.
Range again can also be used, this time to rule out  C. arcuatum, which is a north-westerly species in the UK, with very few recorded occurances in Buckinghamshire.

Microdon myrmicae/mutabilis at Arnside Knott. This is most likely M. mutabilis from the habitat, but it is impossible to split these two species at the adult stage. The larvae live in ants nests.

Merodon equastris, another bumblebee mimic hoverfly.

This is one of the best marked Eristalinus sepulchralis I've ever seen. The lack of dull patches on the glossy looking abdomen, and the fact that it was on the saltmarsh at Leighton Moss point to it being possibly E. aeneus, but enquiries on the Facebook group UK Hoverflies suggest that it is more likely E. sepulchralis. This is another species of hoverfly which appears to be mimicking a fly.

One of several very similar honey bee mimic hoverflies, this is Eristralis horticola. This is a bright looking Eristralis with a dark mark in the centre of each wing.

Eristralis arbustorum, the main identification feature is the unmarked face. Most other similar Eristralis have a dark line running vertically up from the antennae.

Parhelophillus species are very difficult to seperate  and this particular individual can only be called Parhelophillus sp.

However this is a male Parhelophilus frutetorum, identifiable by the long-haired tubercle on the hind femur. On hogweed at Pennington Flash.

This, on the otherhand, can safely be called Parhelophilus versicolor, since the male clearly lacks  the tubercle.

The micro moth, Olethreutes arcuella.

Semaphore Fly Poecilobothrus nobilitatus. This is the male in Dingle Gardens, Quarry Park in Shrewsbury.

The male semaphore fly flicks it's wings at the female in display, hence its name.

Hydrometra stagnorum, water measurer, Sorrowcow pond, Pennington Flash.

Pirata piraticus, a pirate spider carrying its babies on its back, Sorrowcow pond, Pennington Flash.

This photo was taken in County Tyrone, Northern Ireland. This four-spot chaser had flown into the web of the spider, Larinioides coruntus. I would never have believed that just a few strands of web would be capable of holding such a large and powerful predator as this chaser, or that the spider would even consider approaching such an intimidating insect, but the web held and the spider kept its nerve and proceded to spin more web around the dragonflies wings and legs, before killing it by biting it in the abdomen as you can see here.

Ramshorn snail, Sorrowcow pond, Pennington Flash.

The day flying moth cistus forrester Adscita geryon was out in good numbers on the Great Orme in mid June.

Nemophora degeerella

And finally......

Just when I thought that invertebrates were done for the month I was sitting in the middle of a barley field in rural Buckinghamshire at dawn, doing bat emergance survey, when I spotted this guy roosting on top of a culm of barley. It's a purple hairstreak butterfly, surely the most unlikely creature I have ever encountered so far on a bat survey!

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