Showing posts with label Syrphus torvus. Show all posts
Showing posts with label Syrphus torvus. Show all posts

Tuesday, 28 May 2013

Bioblitz!

Last Saturday saw Bioblitz 2013 in Ireland: 4 locations competed to see which could record the highest number of species in 24 hours. The full story is at http://bioblitz.biodiversityireland.ie/

I was at Colebrook where we recorded 1086 species to top the list. My specialist areas were leaf-miners, micro-fungi and hoverflies, but most of us recorded whatever we saw during the day. I didn't manage to photograph everything I recorded, but this post contains some of the more interesting images.

Since I was 'doing' miners, I headed directly for the main wooded area and immediately found many mines of the weevil Orchestes fagi:

Mine of the weevil Orchestes fagi
A couple of things are worth noting about this miner. First, the leaves of beech trees have only been open for around a week, and the mine has already completed. The larva can only eat fresh leaves (when they are very soft) so no time is wasted when the leaves are unfurling. Second, most of our leaf mines belong to moths or flies, with a few sawflies making up the numbers: there are very few beetles that make mines. Finally, miners that make corridor mines (like the first part of this mine) are severely limited in size by the width of the mine and thickness of the leaf. Species that make blotches (like the final part of this mine) can grow to much larger sizes as larvae, and hence result in larger adults. Having said that, the adult weevil is only 3 mm. long.

Staying with weevils, here are two shots of another weevil: Phyllobus glaucus:


The weevil Phyllobus glaucus
The weevil Phyllobus glaucus
This is a feeder on broadleaf trees, usually near water. Thanks to Malcolm Storey for the id on that one. New to my species list.

While I was near the river, I also recorded a few microfungi on grasses and leaves, although nothing new to me.

I also found this stonefly, which appears to be one of the Perlodidae, but I don't have a key to get it any closer:

Adult Stonefly
Stoneflies are always found close to water, since the larvae are aquatic.

Another very fruitful area was the marshy area further along the river. This was a wonderful environment with dappled sunlight filtering down to an old pond. The fringe was surrounded by Marsh Marigolds:

Marsh Marigolds
And Skunk Cabbage, which is an escape:

Skunk Cabbage
Each of the plants is around 1 m. across.
New to my Species List.

Further in, I found the Green Tortoise Beetle, Cassida viridis:

Green Tortoise Beetle - Cassida viridis
The Cassida family of beetles are paranoid about safety: the larvae carry an 'umbrella' of dead skin and dung to ward off predators, the adults are 'stealth'-shaped in order to avoid casting shadows, and when they are flat to a leaf, present nothing for a predator to grasp.
New to my Species List.

The hoverfly Rhingia campestris has a tongue which folds and unfolds in a zig-zag fashion. When not in use, it stores it in the projection in front of its face:

The hoverfly Rhingia campestris

Solitary mining bees are very busy at the moment, stocking up pollen to feed their larvae. There are many species of Andrena, and this seems to be Andrena haemorrhoa, although it shows similarities to a couple of Andrena species that haven't previously been recorded from Ireland.

Andrena haemorrhoa mining bee

This Empid Fly had captured a specimen of Bibio marci:
Empid with Bibio marci as prey
Bibio sp. are known as St Mark's Flies because they normally emerge around April 28th. They are a month late this year.

Syrphus sp. hoverflies can be difficult to separate without a magnifying glass. This male has hairy eyes, which makes it safe to call it Syrphus torvus:

The hoverfly Syrphus torvus

Sunday, 3 July 2011

School Trips

This is the time of year when I take school groups out on walks to show them the delights of our countryside. I'm normally too busy doing identifications to get decent photographs, but I do manage to squeeze in a few.


This is the major season for hoverflies: hedgerows, verges, gardens and woodland are all buzzing with them as they carry out their vital pollination.

This is Cheilosia illustrata, which I only ever find - in small numbers - on Umbellifers (Hogweed in this instance) at the edge of woodland:
The hoverfly Cheilosia illustrata
The larvae of Cheilosia illustrata mine the lower stems of Hogweed.

The Syrphus family hoverflies are all very similar and can usually only be separated by examining microscopic characters.  This is Syrphus torvus, which can be identified by the hairy eyes:
The hoverfly Syrphus torvus (male)

The larvae of Syrphus torvus are aphid eaters.

New to me.

One of the great things about the internet is the way in which it connects people. As a result of online communications, I know that there has been a recent inwards migration of numerous butterflies, moths and other insects; Eupeodes corollae is one of them:

The hoverfly Eupeodes corollae
The larvae of Eupeodes corollae are also aphid eaters.


Soldier Flies are often mistaken for hoverflies, but the wing veins are distinctly different. There are a few metallic hoverflies, so the confusion is understandable.
Soldier Fly - Chloromyia formosa

This is a suitable place to show an Ectemnius wasp. Ectemnius wasps make solitary burrows for their larvae, which they feed exclusively on hoverflies. They have evolved to resemble hoverflies, presumably so that they can sneak up on them without causing them to fly off.
Ectemnius sp. wasp

Sometimes an opportunity arises to take a photograph which definitely fits more into the 'artistic' category: 

This Ichneumonid was closely examining the flowers of Bush Vetch in the hope of finding some larvae to parasitise. I saw this backlit shot as it was moving from flower to flower:
Ichneumonid on Bush Vetch
And now my new favourite photograph:

Ichneumonid parasitising moth larva in Cocksfoot grass
The female Ichneumonid has detected a moth larva inside the seedhead of Cocksfoot grass, and has swung her ovipositor round to inject an egg into the caterpillar. The egg will stay dormant inside the caterpillar until it pupates, at which time the egg will hatch and consume the contents of the cocoon. It takes a great deal of patience to get a shot like that. Each shot requires perhaps 30 minutes of watching the wasp moving from seedhead to seedhead and waiting for the moment of injection. These are my favourite photographs.

This has been a tricky year for Damselflies and Dragonflies: I have seen very few. A trip to a local pond solved that for me. This is The Blue-tailed Damselfly:

Blue-tailed Damselfly

And this is the Variable Damselfly - Coenagrion pulchellum, which is new to me:
Variable Damselfly

A tall, elegant grass has been bothering me for a couple of years, so I decided to identify it this year. It's Tufted Hair Grass - Deschampsia cespitosa - which forms tufts and has stems that reach up to my shoulders. I usually find it where I would normally see Damselflies, so they must need similar conditions.

Tufted Hair-grass Deschampsia cespitosa
New to me.