Photo-Stacking at the Angela Marmont Centre

On Wednesday I was very lucky to be able to visit the Angela Marmont Centre at the Natural History Museum in London. The Angela Marmont Centre for UK Biodiversity is an amazing place for naturalists in the United Kingdom that is available for anyone to use. With such a range of resources such as the photo-stacking equipment; a huge library; and the whole of the British collections, it really is invaluable.

I have used the photo-stacking equipment here once before and I really do think it is a very clever piece of kit. It takes lots of photos (I took around 65 for each specimen) all at different focal points and then merges them together using software called Helicon Focus. With all of the different focal points on the specimen covered, there is no part of the specimen that is out of focus and it is all very sharp. This produces a clear image that can show many different features, excellent for identification or illustration of species.

I think that photo-stacking is incredibly useful for a number of projects. For example, if you were writing an identification guide and space was limited, you could in many cases show all the features of an organism in just a single photograph. Also for illustrating an article or a short piece of writing where there is a limit to the number of photographs, you could include just a single image with all of the key features clear and visible.

Below are a few of the photo-stacked images that I took using the equipment. You can find all of the images of the identified specimens on this page. I still have some photographed specimens that I need to identify, and I will post them on that page once I have put a name to them.

Stenodema calcarata labelled

 This Mirid bug is just 8mm from head to end of the abdomen. Its distiguishing feature is the two short spines on the hind femur. This separates this species and the very similar Stenodema laevigata.

 

 

Poecilus cupreus labelled

This is the largest specimen that I photographed, 13mm. This rather big Carabid beetle was swept from a patch of nettles, much to my surprise!

Agriotes pallidulus labelled

This is a very small Elaterid, or click beetle, only 4mm long. When they are threatened they often roll onto their backs and catapult themselves upwards to escape predators and they make a ‘click’ sound as they do so.

 

A Quick Walk down Mill Lane

 

This morning I walked along Mill Lane which runs along the east side of Hedgecourt Lake. What struck me first was the height that the Water Dock had grown to compared to the last time I visited the lake. It was at least the height of me if not taller. This is not unusual though, some plants can grow to more than 2 metres. This plant can grow in very tough conditions, these ones grow on the concrete wall of the lake against the hard wind and the severe waves that sometimes form. Equally large were the leaf mines that covered almost half of each leaf. Some leaf-mined leaves were about 75 centimetres long, so the leaf mines were huge! Whose larvae are growing up inside those leaf mines?

To identify the culprit, I visited a site I use regularly: http://www.ukflymines.co.uk
I went to the Rumex (Dock) section of the site and I saw that luckily there are not that many leaf mines on Dock in Britain. From the photos on that page I think that my species is Pegomya solennis. Pegomya solennis is a species of fly, unfortunately not new for my list although very impressive. This species is not a large fly, but the key to its very big mines lies in teamwork. In each mine there are two or more larvae that at first work together making a wide corridor. They then separate and each form a large blotch which all fuse together making one large blotch from which they feed. Sometimes the blotch size is increased even further when the blotch joins the blotch from a different leaf mine.

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The larvae feed on the leaf from inside these blotches.

Along the grassy verge between the lane and the lake there are several large patches of Bird’s-foot Trefoil, Ribwort Plantain and Black Medick. I thought these large patches might hold some specialist species but alas not much was swept from them using my net. The only species of interest was a single Platycheirus peltatus, a species of hoverfly and my 94th fly species on my Pan-species List.

Moving on, it was still windy and not too warm so most of the wildlife was hiding away. I stepped down onto one of the fishing jetties to get a closer view of the lake wall without the risk of falling in to the nippy water. On top of the concrete wall was a hole, which was occupied…

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The white spherical object in the centre of the hole is an egg sac, which belongs to a very large spider. I tried to coax it out from the hole, but it wouldn’t come. I’m not certain what it is, but one possibility is the mouse spider, Scotophaeus blackwalli. However it is usually found in sheltered places indoors so I’m not sure what it is doing on this exposed wall if I am correct.

On some more Water Dock further along I noticed a colony of aphids. It is often not hard to identify aphids when you see a colony on a particular species of plant. For this one I just searched with Google ‘aphids on dock’ and I was presented with two options: Aphis rumicis and Aphis fabae. Aphis rumicis is more plant-specific, being found on mainly dock and sometimes on rhubarb. Aphis fabae (the Black Bean Aphid), is much less so being found on a wide range of vegetables. Unfortunately the two are quite similar, although I am leaning towards A. fabae due to the paler legs shown in many of the photos I have seen on this species. My 50th hemipteroid (bug) for my Pan-species List! In my (not great) photo, the colony appears to be being attended by a Lasius ant.

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Suddenly the sun emerged from behind the clouds and everything seemed to suddenly wake up. There were loads of umbellifers on the lake shore which were great for invertebrates although I had little time to examine them closely. What I did find, however, is a mini-miner. These are very tiny bees in the genus Andrena, which I don’t come across too often. Their larger relatives in the same genus I more often come across. There are 10 mini-miner species compared to 57 other Andrena species, although I find them much harder to identify. Also, many of them have very restricted distributions.

I potted this tiny bee and when I arrived back home I took a few hasty shots though the gap between the lid and the pot. The long, very white hair caught my eye and helped me when I attempted to identify it using Steven Falk’s Field Guide to the Bees of Great Britain and Ireland. Currently I think the most likely species is Andrena niveata, the Long-fringed Mini-miner. Modern records are restricted to South-east England and it is not very common, therefore I am tentative with my identification and I will hopefully get it checked under the microscope or with an expert. In the book it says: ‘the body hairs are much whiter than in other mini-miners…the overall effect is thus of a very silvery, strongly marked mini-miner’. This definitely fits my bee.

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I was very pleased with the number of interesting and new species that I found this morning, given the short amount of time and the unfavourable weather conditions. I can’t wait until the summer holidays when there will be more time to explore!

Published!

This summer, I went to Knepp Estate for an Amateur Entomologist’s Society (AES)field meeting on grasshoppers and crickets. It was really interesting, but the best part was being asked to write an article for the Bug Club magazine for junior AES members on a bug that I found! This was the first time this has happened. It was published in the October issue of the magazine, here it is:

“On August 12th this year, a few keen bug-hunters and I made the journey to Knepp Estate near Horsham, West Sussex for an AES field meeting. Knepp Estate is a wonderful place and is currently undergoing a ‘rewilding’ project, where people try to restore a site back to the days when wildlife was plentiful in the area. It consists of a number of different habitats, but mainly scrubby grassland with a few lakes and ponds scattered around.”

“The focus of this AES field meeting was on grasshoppers, crickets and related species. However, the star species was actually a hemipteroid (a ‘true’ bug): the Tortoise Bug (Eurygaster testudinaria). We came across it while we were making our way through a marshy habitat, looking for a species of cricket called the Short-winged Conehead. The first we saw of the Tortoise Bug were actually two nymphs (pre-adults), sitting cosily on top of a Marigold flower. They look like typical shieldbug nymphs, with an oval-shaped body and a dark pronotum (the section of the body directly behind the head). However, the feature that stood out about this nymph was the fact that the main colour was a light rosy pink.”

“To my surprise, an adult was found soon after. However, it’s much harder to confirm the identification of an adult. Like quite a few other invertebrate groups, you have to peer really closely at obscure parts – in this case the front of the head. The Scarce Tortoise Bug is the species we have to keep in mind, and the easiest way to separate it is to check if there is a slight depression (dent) in the front of the head. Only the Tortoise Bug has this depression at the front of the head, but it’s very hard to see. We had to look really hard through our handlenses, but in the end we reached the conclusion that the depression was evident, making it the much more frequent Tortoise Bug. If only bug identification could be simple!”

Adult

Adult

Nymph

Nymph