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6 July 2017

6 July 2017 – Caddis fly Headache

(Ectoedemia sp) or (Stigmella sp) 

The trap was placed in the garden instead of the quarry to figure out if there is any noticeable difference between the two areas. We are getting more species but I believe that may be because of the time of year rather than the placement. 

After accidentally grabbing hold of a slug under the rim of the trap, the second time this week unfortunately, I went through the trap taking pictures of anything I was not familiar with. There were quite a few moths I did not recognize, both macros and micros. The macros unsurprisingly, took a lot less time to identify, except one which I am waiting for confirmation. The micro moths occupied most of the rest of my day.

In the photograph above can be seen a moth that we are unable to identify.  It is either an Ectoedemia or a Stigmella – but we can’t tell which.  The sizes of the moths are similar, the markings are similar and both are reasonably common.  The only way to determine which is by dissection.  We have had an Ectoedemia species once before so we can’t claim a new species for our unknown micro.

(Swammerdamia caesiella or Paraswammerdamia nebulla

Another micro we found difficult to identify is in the picture above. I believed it was either a Swammerdamia caesiella or a Paraswammerdamia nebulella. After consulting with Charlie, he informed me that it cannot be accurately identified but that I was correct in that it is one of those two. Both species are common in Britain, the larvae of Swammerdamia caesiella feed on birch (Betula) while the larvae of the latter feed on hawthorn (Crataegus) and rowan (Sorbus aucuparia).

While we have had Swammerdamia caesiella before, we have not had Paraswammerdamia nebulella. We cannot list this moth as a new species however, as it is not certain which one it is.

Micro caddis fly 

When I was examining the sides of the trap itself, after having gone through the egg boxes, I saw a micro moth and persuaded it into a tube. After experiencing several headaches trying to both identify the moth and trying to get a decent photograph, I eventually got a picture of it which showed the insect’s miniscule features. Even with a detailed photograph I was still flipping through the entirety of the micro moth book trying to find a similar pattern and shape. Asking Charlie again for his help, he told me it was a micro caddis fly and not a moth at all. A detail I had missed while looking at the photograph were the little hairs on the body of the caddis. I had forgotten that moths do not have hair but have scales. This trap really proved how difficult identification can be, especially when some of the defining characteristics are hard to notice with the naked eye.

Post : Walter Chen [UPenn intern]