what kind of grub is this ?

vin sent me this pile of photos of grubs asking if i could help him identify them. he knew i wouldn’t have a clue but wondered if you did.
He writes:

I wonder if you’d be kind enough to post these pics of a tiny grub I
found today in the hope that some knowledgeable reader can identify
it. I’ve had no luck so far on Google.

It was in this kind of discus-shaped sac-thing, just lying in a
flower -bed. It measured a quarter of an inch (6mm) across, and when
the grub wriggled (more like a convulsive jerk), the whole thing
moved. When I first saw the movement in the dirt, I had assumed an
ant was tugging at a leaf disc (as they do), but it wasn’t really
going anywhere, just turning around and jerking about. Thanks Vin


3 thoughts on “what kind of grub is this ?”

  1. To name an old radio programme…
    “I’m sorry I havn’t a clue”.
    But it puts me in mind of an even older song…
    “What kind of fool am I”

  2. Brilliant photographs, thanks Vin. I think I may be able to help! I think it is most likely to be the larva of a micro-moth called Incurvaria. If you posted from Southern England it is probably Incurvaria pectinea – it is found in Berkshire and Hampshire. Sorry to use the Latin name but I don’t think it has an English one, although the Incurvarias as a group are known as Longhorn moths. The wingspan is about half an inch (15mm) or so. The larva (caterpillar) is a leaf-miner, somehow managing to burrow and feed between the top and bottom surfaces of a leaf. Then by some magic it manages to cut a leaf disc out around itself which falls to the ground. It then uses it a mobile case, which is what you have found. I would hazard a guess that you found it under a Hazel tree, although Birch, Hornbeam, Apple and others are also used.
    There’s another possibility that it is a leaf-mining weevil called Rhyncaenus, or another type of moth called Antispila, but I don’t think their cases are mobile like this one.
    Yet another example of the myriad wonders of Creation that are all around us if only we have eyes to look and see!

  3. Thank you, Alan. Amazing that Dave happens to have a moth-expert friend. I live in west London, so not far from Berkshire. I’m not sure about the tree the Incurvaria came from – we do have a lot of sycamore but there could well be a hazel there too. I’ll check for the holes in the leaves when the weather clears up. I thought it was probably a leaf-disc, but wasn’t certain. What a strange life-cycle! Do they stay in the sac to pupate? There don’t seem to be very many pictures like mine on the internet, (for example Bioimages have only pictures of leaves with holes in) so I wonder if anyone would like to use them. Thanks again.

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