Tuesday, 2 August 2016

Invasion Of The Lilly Snatchers

Last week I witnessed a strange phenomenon at the kitchen garden pond. The entire water surface was covered in a dusting of white flecks. It seemed to me that these were hatching flies of some kind, but it was not obvious what they were to the naked eye (not to my declining ones anyway). I returned with a macro lens to discover a flotsamic mess of drowning insects and shed skins. Where any plant protruded from the water it was covered in survivors as were the lilly pads and their flowers. This was, I was to discover, an explosion of Water Lilly Aphids.

As I tried to photograph these 1-3mm long sap suckers I began to notice all the predators in attendance. Lots of pond skaters and backswimmers, but more to my amazement was witnessing a tiny parasitic wasp come and inject her egg(s) into a hapless aphid (who was perhaps at the time wondering how it had had the good fortune to avoid the drowning fate of so many of its siblings).

On reviewing my photos I then saw more than one aphid carrying what looked like fly eggs on their backs. These I now believe to be hover fly eggs. I can't imagine the aphids have a particularly long life, so both wasp and fly larvae must develop very quickly, perhaps moving onto a secondary host if they themselves outlive the aphid?

Anyway, the moral of the ongoing story is that just because there are no fish in a pond it doesn't mean nothing is going on.

Mysterious debris on surface of kitchen garden pond

Debris revealed in close up as plague of Water Lilly Aphids

As I was attempting to get the aphid on the left in focus a tiny (3mm) parasitic wasp appeared...

The wasp also evaded my focus, but quickly approached the aphid...

Swiftly injected its egg...

...and left the scene in a blur

A huge number of predatory Pond Skaters also in attendance

Aphids on iris leaf. On the right of frame is an aphid covered in what I think are hover fly eggs

Aphids watched by Midge

Pond skater floating on floating feather floating

A Backswimmer, presumably partial to an aphid, but not witnessed doing anything unpleasant (unless you count breathing through its rear end).

1 comment:

  1. You should have said "derrière" rather than "rear end" cos "rear end" just makes me think of great big bums and stuff. Thanks for another wonderful blog.