Not always straightforward

During my Garden Bioblitz of the the 6th June, I found a moth case on a cotoneaster leaf. I tried to identify it by using this webpage and I thought it looked most like Coleophora trigeminella. I was very excited by this as the species hasn’t been recorded on Cotoneaster in the UK before, only in Europe. Could I have discovered a new foodplant for this species in Britain?

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I emailed the Surrey moth recorder, Mr Graham Collins, with news of my finds. I asked him whether it was likely to be Coleophora trigeminella or something else. He kindly responded saying that he didn’t think that the larval case belonged to this species but Coleophora serratella which is ‘probably the commonest species of British Coleophorid’ according to the UK Moths website. I was quite disappointed!

However, why was it on a cotoneaster leaf? The larvae usually feed on hazel, birch, elm or alder. It is most likely that the larvae fell from the foodplant (there is a birch tree straight above the cotoneaster) on to the leaf where it formed the case, or the larvae wandered off the leaf looking for a better place to create its case.

When I returned to the same leaf nearly a fortnight later, on the 18th June, I was given a huge surprise. The adult moth had emerged from the case overnight and was resting parallel to the case! It was so fresh in fact that the antennae were not resting forward in the typical coleophorid fashion but running backwards along the body! I sent this photo to Mr Collins.

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I thought that it was too light for Coleophora serratella and the ochre colour matched Coleophora trigeminella. Could I have found a species of moth that hasn’t been seen in Surrey for nearly half a century? Unfortunately that was not to be the case. Mr Collins responded writing that he now thought that the moth is either Coleophora flavipennella or Coleophora lutipennella. The larval stages of both of these moths feed on oak leaves, which makes sense as there are several large oak trees which also have branches above the cotoneaster bush. The larva probably fell from the leaves.

However, it is not possible to separate moths of those species without examination of the genitalia. For this I sent the moths off to Mr Collins by post and he kindly looked at them under the microscope. The genitalia point to Coleophora flavipennella, which I think might be the least common of the pair although I am not certain. The genitalia of C. flavipennella look like this:

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Compared to the genitalia of C. lutipennella:

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There is quite a lot of difference! This is a new species for me and I hope this blog post shows that often identification is not that straightforward.

(genitalia photos from http://www.mothdissection.co.uk)

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1 Garden, 24 Hours, 184 species!

…and counting! Last Sunday, the 5th, I took part in the Garden Bioblitz for the first time. The aim of a bioblitz is to record every species you find in an area within a period of time. For the Garden Bioblitz, you record every species you find in your garden during a 24 hour period.

To begin my Garden Bioblitz I looked through the moth trap from the previous night. There was a very wide range of species, including 23 that were new to me. The highlights were:

  • Great Oak Beauty – annual in Domewood, but Nationally Scarce B (NB).
  • Cacao Moth – usually found indoors in stores of products such as nuts, almonds, tobacco and cacao. I’ll be checking my muesli from now on…
  • Scorched Wing – a beautiful moth which is also classed as Local. There were 8 in the trap.
  • Peach Blossom – a great moth with a great name although quite common.
  • Cypress Carpet – quite an uncommon moth, which arrived in Britain through its host plant, cypress. There are lots of Lawson Cypress trees in the garden which probably explains its occurrence here.
  • Diamond-back Moth – for some reason, I rarely see immigrant moths. The Diamond-back Moth is only the third immigrant moth I’ve recorded. I recorded it for the first time during the last weekend of May, but there were 29 in the trap!

I also caught a very interesting beetle that had a very pungent smell. I thought it was a sexton beetle and I was right. However, I wasn’t too sure which species it was. It was all black and luckily there are only two all-black species in the British Isles: Necrodes littoralis (the Shore Sexton Beetle) and Nicrophorus humator (the Black Sexton Beetle). It turned out to be the Shore Sexton Beetle due to the antennal clubs not being brushes as in the Black Sexton Beetle. Thanks to Chris Brooks on iSpot for the identification. Sexton beetles are interesting because they feed on dead animals. If the dead animal is small then they will bury it to keep other scavengers from taking it. They do this by excavating the soil under the body so that the dead animal sinks into the ground. The adults lay eggs nearby and when the larvae hatch they crawl to the dead animal to feed and even be fed by the adult. Even though this beetle was caught in the moth trap there isn’t necessarily a dead animal nearby as they can fly quite long distances in order to find their food.

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After I had finished looking through the moth trap, I walked around the garden listing all the wild plants. Before I added the plants I already had a list of almost 70 and there was still lots to identify! Other non-moth highlights included a Canada Goose flock flying over and the first Grey Heron I have seen fly over the garden in more than a year. After I finished off the plants I had breakfast, meaning that I had a list of 130 before breakfast. Things were going well!

It wasn’t just plants that I added to my list on the walk around the garden. It was quite early but there were still some insects on the wing, including Rose Sawflies, Speckled Wood butterflies, Large White butterflies and various bees. I was even lucky to see the young fox that has been hanging around the garden for the past few weeks. It is not that shy, here is the photo I took when I first spotted it:

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After breakfast I looked under the logs and stumps in my garden. As always, they were brimming with slugs, beetles, woodlice and other creatures. The most common ground beetle was Agonum emarginatum, a species usually associated with damp habitats near freshwater. This makes sense as most of the stumps were near our tiny pond. The list of slug species was quite good too: Budapest Slug, Leopard Slug, Yellow Slug, Dusky Slug, Greenhouse Slug and Ambigolimax nyctelius, the species I found new to Surrey last year. When I first found it I had to send it off to Wales to get the genitalia looked at, but this confirmed the scientist’s suspicions that there were slight morphological differences between Ambigolimax nyctelius and the Greenhouse Slug. In my experience, Ambigolimax nyctelius is more boldly marked than the Greenhouse Slug.

Finally, the highlight of my bioblitz was finding an amazing fly species that I have been looking for in my garden since Tony Davis told me that it was likely to appear here. It’s not rare or scarce, but it is impressive. It is a species of hoverfly that mimics bees. It has many different forms that each mimic different bee species. It’s called the Narcissus Bulb Fly or the Greater Bulb Fly and it’s eggs are laid in bulbs of various species such as garden daffodils. I found a mating pair on a Bulbous Buttercup, perhaps the plant that the eggs were about to be laid in? The male seemed to be an Early Bumblebee mimic:

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However, I’m not sure which species the female was impersonating:

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It seemed to be all black except for the last 4 or 5 abdominal segments, which were off-white.

So, I’m currently on 184 species and hope to identify a few more for my bioblitz list.