Wednesday 19 October 2011

A Popular Oak Leaf

Popular oak leaf on Hayes Common.  18 September 2011.
Popular oak leaf on Hayes Common.  18 September 2011.
Oak trees support many other species and are ecosystems in themselves. This single leaf illustrates some of that!

I am no expert on galls, but they are interesting and some of them are easy to identify. Not these, unfortunately.  This leaf has up to three different types. The large round one on the right might be a Striped Pea Gall, caused by the gall wasp Cynips longiventris, though it is not as colourful as I would expect. There are also some small green galls lower down the midrib, possibly younger versions of the same, though if so their timing is odd; and some small black ribbed galls on the side veins.

The tip of the leaf, on the right, is covered with droppings and silk strands, showing that something has been living there, curling the edge of the leaf around for protection. The same has happened where the edge of the leaf is curled under at the bottom of the photo.

The white patch in the middle is where something has eaten out the green goodness from between the upper and lower surfaces of the leaf.

There are holes where something has either eaten or taken away chunks of leaf.

There are some white cast-off skins showing where aphids have moulted.

And finally, I  leave it to you to spot the scale insect, tucked in and hanging on quite happily.

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