Friday, 25 May 2012

Under pressure

High pressure, as in sunny weather, brings out all the insects, so things have been quite busy.

The Common Carder Bumblebee - Bombus pascuorum - is the latest of my local bumblebees to establish a nest. Most of the specimens seen around are still queens stocking up their reserves before the workers emerge for the season:

Common Carder Bee on Bush Vetch

Members of the Empid family of flies are commonly called 'Dance Flies' due to their habit of forming mating clouds where individuals bounce vertically within the cloud. They are voracious predators, sucking fluids from their victims with their long proboscis. Sometimes, however, the proboscis is used to reach nectar in flowers:

Empid fly on Creeping Buttercup

Hoverflies are everywhere at the moment, which is good news: they pollinate flowers, trees and crops, so the more we see the better. Eristalis arbustorum can be separated from other Eristalis species by the lack of a dark stripe down the face in association with the swollen rear leg which is conveniently extended in this shot:

Eristalis arbustorum hoverfly

Rhingia campestris is an increasing species which used to be found mainly near farms (the larvae live in dung), but is now found in most habitats:

Rhingia campestris hoverfly
That long 'snout' contains a folded-up tongue which it unfolds to suck nectar that other insects cannot reach.

Leaf-mining species don't wait long after the leaves emerge before laying their eggs: they have to make use of their only food as soon as it's available. This is the very common Phytomyza ranunculi, which mines various members of the Buttercup family:

Phytomyza ranunculi mining Creeping Buttercup

I increased the light intensity on this shot to show the larva more clearly:
Phytomyza ranunculi close-up showing larva in mine
The mines of Phytomyza ranunculi can be separated from those of the much rarer Phytomyza ranunculivora by the pattern of 'frass' (dung droplets), which are joined up ("string of pearls") in P. ranunculi, but are quite separate in P. ranunculivora (Click here for comparison).

Most predators are adept at catching their own food, but some chance upon their next meal whilst simply wandering about. I saw this Lesser Dungfly discovering an already dead fly and after a brief inspection, it wasted no time in tucking in:

Lesser Dungfly with discovered corpse

I previously showed the newly-laid egg of the Orange-Tip butterfly. As expected, the egg has now turned orange and should hatch in the next day or two:
Orange Tip butterfly egg on Cardamine

Good weather encourages moths to emerge and they can often be seen beside lights at night: I keep one light running to see what I can attract. This is Common Marbled Carpet - a very variable moth (and this specimen is quite worn, making identification even more tricky):

Common Marbled Carpet moth

Just to show what we're up against in moth identification, here is a shot of Goldenrod Pug - Eupithecia virgaureata:

Goldenrod Pug moth
Compare that with my previous shot of the same species here. The only features in common are the (faint) elongated wing spots and the tuft of whitish scales behind the thorax. This colour variation has been named as f. nigra for fairly obvious reasons.

Lastly, a shot of the very common Buff Ermine moth. The caterpillars are very common in wooded areas and look like the business end of a stiff yard brush.

Buff Ermine moth


Caroline Gill said...

As ever, Stuart, lots of interest and lots to learn!

Toffeeapple said...

I have to agree with Caroline!

Jenna said...

Lot of great texts, i think that hours of patient writing are behind