While exploring the area for suitable nightingale habitat for the BTO survey I was over at Hadlow Place in rather cool, breezy and occasionally drizzly conditions. In the avenue of birches between the caravans I came across several leaf miners, all within arms breadth, on the birch leaves. This is a picture of the top surface of one of the leaves showing the mined patch, more or less limited by the midrib and laterally to the main side veins.
One of the mined patches had what looked like a pupal case suspended below the damaged area. When I looked, all the other patches had what looked like a small circular "attachment scar", and I was pretty sure that I was looking at pupal cases, most of which had either dropped off or been removed.
However on looking on the British Leaf Miners website, the best fit was probably Coleophora serratella, which is actually a "cased larva". This became rather clearer when on looking out the specimen from the bottom of the camera case a few days later, the larva took off moving quite quickly, using its head (and front legs?) to move across paper and plastic very effectively, holding the case at about 45 degrees from the horizontal. This is a picture of the cased larva in situ, again with the case at more or less the same angle. This is the second stage of the larval case. When this larva pupates, it does so in the larval case, but on the upper surface of the leaf, and in May.
In this cropped picture the darker area is the body of the larva, I think. The yellowish brown colour of the case fits with the published description, on the UK moths website. I think it isn't not dark enough to be C. milvipennis, one of the other species found on birch.
One of the mined patches had what looked like a pupal case suspended below the damaged area. When I looked, all the other patches had what looked like a small circular "attachment scar", and I was pretty sure that I was looking at pupal cases, most of which had either dropped off or been removed.
However on looking on the British Leaf Miners website, the best fit was probably Coleophora serratella, which is actually a "cased larva". This became rather clearer when on looking out the specimen from the bottom of the camera case a few days later, the larva took off moving quite quickly, using its head (and front legs?) to move across paper and plastic very effectively, holding the case at about 45 degrees from the horizontal. This is a picture of the cased larva in situ, again with the case at more or less the same angle. This is the second stage of the larval case. When this larva pupates, it does so in the larval case, but on the upper surface of the leaf, and in May.
In this cropped picture the darker area is the body of the larva, I think. The yellowish brown colour of the case fits with the published description, on the UK moths website. I think it isn't not dark enough to be C. milvipennis, one of the other species found on birch.
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