Tag Archives: Iris Sawfly

Summer in Gunnersbury Triangle

Suddenly it’s actually hot in the nature reserve.

A handsome brown Shield Bug
A handsome brown Shield Bug

The wildflower meadow in front of the hut shimmered in the sunshine, with bumblebees buzzing around the many Red Campion flowers. A Brimstone visited, for once perching quietly to drink nectar from the flowers. A large brown Shield Bug flew in and clambered up a twig in the hedge. A Red Admiral flew over too. We spent the morning making pegs – like overgrown foot-long sharpened pencils – to fix down the long thin logs we’re using as path edgings. It was pleasant working as a team, with cutting to length and then sharpening with the billhook going on simultaneously.

In the woodland where little shafts of sunlight reached the understory, Speckled Woods danced about or perched.

Speckled Wood in the sunshine
Speckled Wood in the sunshine

Down at the pond, Azure Blues (the ones with the little drinking-cup mark at the base of their abdomens) darted about, chasing each other off perches and flying in cop with what seemed to be rather few females compared to the number of eager males. A smaller number of Large Red Damselflies similarly chased and mated.

Azure Blue
Azure Blue

The “Mangrove Swamp” has lost almost all its standing water now: last week it had risen after being very low, but it only takes a few days for the level to fall dramatically. The frog tadpoles in the last pool were wriggling in a few centimetres of muddy water. I scooped them up in a bucket and popped them into the pond, where they’ll have to take their chances with the ducks alongside the toad tadpoles. The toad-poles may be somewhat distasteful like the adults, so perhaps the frog tadpoles are more palatable?

Toad Tadpoles (Toad-poles?)
Toad Tadpoles (Toad-poles?)

The Yellow Irises on the pond are starting to suffer from Iris Sawfly, a few of the leaves showing many small bite-marks along their margins.

Iris Sawfly on Yellow Iris leaf
Iris Sawfly on Yellow Iris leaf

A small diving beetle obligingly came to the surface to replenish its air supply, staying up there for a minute and then zooming down to the bottom when I came close.

A small Diving Beetle
A small Diving Beetle; could be Acilius sulcatus

 

Summer Bugs at Gunnersbury Triangle

Cinnabar Moth on rusty False Oat Grass
Cinnabar Moth on rusty False Oat Grass

Ragwort is at full height now and will soon be flowering. A few adult Cinnabar Moths are about; they will mate and lay eggs on the ragwort, which is in several places around the reserve, and then we will have the fine black-and-orange banded caterpillars in quantities, eating the Ragwort to pieces. They are poisonous with alkaloids taken up from the plant, so few predators eat them: an exception is the Cuckoo, which seems able to cope with the chemistry.

Iris Sawfly on Yellow Iris, with examples of how it damages leaves
Iris Sawfly on Yellow Iris, with examples of how it damages leaves

Iris sawfly caterpillars are starting to chew inroads into the spearblades of the Yellow Iris; they are rather like moth caterpillars, but with rows of little dots on their backs and different numbers of prolegs.

Fox run down grassy bank
Fox run down grassy bank

It looks as if there are young foxes about; a very well-worn run goes straight up the grassy bank into the bushes, and the grass nearby is much trodden down.

Neighbours
Neighbours

The new buildings towering over the reserve are approaching their final shape; it will be a relief when the roar of heavy engines and the squeal and clatter of caterpillar-tracked bulldozers subside into history. There was a horrible accident on the building site this week when something fell from a crane; three workers were injured, one seriously, and the air ambulance arrived, followed by the health and safety inspectors.