Wednesday, 3 August 2011

Every cloud

The weather has been abysmal for several days, with bad light even when it has been dry. Today I saw blue gaps in the cloud, so I ran for the hills, where the Angelica is abundant.

This hoverfly got me rather excited, because I knew I hadn't seen it before. Several shots were rattled off and anticipation was high during the rest of the photography session. When I got the pictures back to the computer and opened the books, I was slightly disappointed to discover it wasn't a new species for me, but merely a new colour variation of one that I had seen once before. It's the orange and black version of the bumblebee mimic Eriozona syrphoides.

The bumblebee-mimicking hoverfly Eriozona syrphoides
Eriozona syrphoides is the only bumblebee mimic to have an obtusely re-entrant (curved) vein at the position indicated by the arrow.

Note. I have amended the identification of this hoverfly as a result of a much better set of photographs taken a few days later.

Here's a shot of it beside an ichneumonid:

Eriozona syrphoides (right) and ichneumonid (left)

Staying with ichneumonids, this one has a quite impressive ovipositor:

Ichneumonid with long ovipositor
I saw a few of those wandering over Knapweed flowerheads, so we know what that ovipositor is used for.

This large brown specimen looks to be close to the Ophion family:

3 cm. ichneumonid

Dungflies are voracious hunters as adults (they're probably making up for all the dung they eat as larvae.) This one is making a meal of a smaller sawfly:
Dungfly with prey
But this dungfly has fallen foul of a little cream-coloured spider:

Spider with dungfly as prey

Now that's a truly vicious circle.

I was quite surprised to find a pristine Red Admiral butterfly nectaring on the Angelica:

Red Admiral butterfly
It's absolutely pristine, with no wear whatsoever, so it's clearly one of the local offspring of the early summer migrants. These feed solely on nettles as caterpillars.

At this time of year I always look closely at clusters of aphids on Knapweed. The larvae of the hoverfly Syrphus ribesii consume large numbers of aphids, and the female always makes sure her offspring have an adequate supply:

Larva of Syrphus ribesii with aphids

Meliscaeva cinctella is one of the later hoverflies, usually to be found from August onwards. Its larvae are also aphid eaters, but solely on tree-dwelling species, such as the Wooly beech aphid.

Meliscaeva cinctella hoverfly

Fairy Flax is a very delicate little flower which I tend to find near the edges of forestry, or along forest paths:
Fairy Flax

Just as I was getting out of the car, this leafhopper flew over my shoulder and landed on the path in front of me. Click.
The leafhopper Cicadella viridis


Emma Springfield said...

I always have a hard time deciding which of your pictures I like best. I had almost settled on the dung fly until I saw the delicate fairy flax. Maybe I don't need a favorite after all.

Rob said...

The ovipositor and antennae of that ichneumonid seem to triple the length of the rest of the insect - with such overhangs it must be a skilful flier.

Stuart said...

Emma: Fairy Flax is a tiny flower which usually defies all attempts to focus on it. Its alternative name, Purging Flax, hints at its previous use as a violent purgative.

Rob: Ichneumonids with long ovipositors often have long antennae because they are used to detect deeply buried or hidden hosts. The antennae guide the ovipositor very accurately at a distance where the eyes of the ichneumonid would be useless, or even where the ichneumonid would have a blind spot. In terms of flying, some of the smaller species can hover in the area where prey might be found, but in general, ichneumonids are very bad fliers, probably because of the very bad aerodynamics. So you're right.....the fact that they can fly at all must demand great skill.

Gill said...

"Fairy Flax is a tiny flower which usually defies all attempts to focus on it." I can confirm that - the hours I've wasted trying to get a decent shot of such a beautiful little flower. Stuart's is fantastic.

And I love that portrait of the Meliscaeva hoverfly.

" The larvae of these hoverflies live on the debris in bumblebee nests, so it would be very interesting if the different colour versions of the hoverfly were to be found in different bumblebee nests." Indeed it would, and I shouldn't be at all surprised if that turned out to be the case.