Are we sitting comfortably…then let me begin.
It’s been a while since we included invertebrates in some detail from the marsh on this blog. As I constantly remind everyone, there is a lot more to see than just birds, especially in the quieter summer months. This is partly due to the fact that much of the marsh is unimproved and the vegetation is lush. As the temperatures have risen, so has the emergence of creepy crawlies become more apparent and any walk will turn up many surprises.
One of the nicest looking bugs was a beetle that I chanced upon below the old birdlog situated at the south-east corner of No.1 tank. It’s long curved zebra-striped antennae immediately caught my eye and I managed to secure a quick snap with my camera. Fortunately it was an easy one to identify and goes by the long-winded name Golden-bloomed Grey Longhorn Agapanthia villosoviridescens (pictured at top of page), a species with a more southerly distribution and with relatively few sightings this far north. It likes moist meadows with nettles, Hogweed and Cow Parsley, all of which were present. I also found another on my next visit.
Whilst I was looking around a marshy area near No.4 tank I found a couple odd-looking flies. The first struck me as very different to what I’d noticed previously and although it sat there for a long time, I was having trouble focusing my camera and all I have is a shot from the rear, but enough to identify it as Sepedon spinipes, a snail-killing fly (or marsh fly). The angled back legs with spines are used to grip the female when mating. The larvae feed on small aquatic snails and can eat between eight and fifty as they grow. The species are not common in Cheshire.
The second fly was like a miniature grizzly bear, quite simply the hairiest fly I’ve ever seen. There are several closely related and difficult to tell species in Britain, but again, there are not many local records of this species the only one in Cheshire, Thereva nobiltata. The larvae eat everything from rotting plants to other insects and worms. What a great looking insect!
There are also a lot of hoverflies on the wing at the moment. One jet black with long wings was sunning itself on nettles on the track below the old log. Cheilosia variabilis is a species that inhabits damp woodland and stream sides and is one of several Cheilosia species.
Another specialist species which is often abundant in beds of Phragmites and other tall emergent vegetation in ditches, ponds and marshy areas is Tropidia scita (image below), a small hoverfly with bowed legs which is quite distinctive once you ‘get your eye in’. There are lots in all suitable habitat across the Frodsham Marsh.
Of the Spring hoverflies that is abundant along woodland rides, edges and hedgerows is the easily identified Leucozona lucorum, a distinctive black and white species with a golden thorax. There were several below the old birdlog and along the early part of No.6 tank on Moorditch Lane.
Even commoner are those hoverflies belonging to the Eristalis group. They have a loop in their vein R4+5 which immediately points to this genera although a couple of other species share this feature.
An early species is Eristalis pertinax or Tapered Dronefly, so named because of its triangular-shaped abdomen. It is widespread and flies in most months of the year.
Whilst I was looking or hoverflies in a marshy bit of ground next to a patch of open water, I noticed some interesting looking spiders that attempted to hide as I approached. They would leave their webs and run to a blade of grass and seemingly vanish. When I did manage to track one down, I found it sitting with its legs stretched out in front and behind it, although the image shows one more relaxed, an example of which is pictured below. They are not fairly easy to identify but the common one in that type of habitat is Tetragnatha extensa (image below) more commonly known as a Stretch Spider or Long-jawed Orb Weaver. They inhabit vegetation near water and build orb webs to catch prey. They can even run on water.
There was also an emergence of Blue-tailed Damselflies, the males floating about like puppets in the breeze. Relatively easy to identify, they are a common species here.
Tiger Cranefly Nephrotoma flavescens this is distinctive and is attractively marked yellow and black. There are several closely related species and telling them apart is not easy. I found some along the track below the old birdlog where the hawthorns and long vegetation with umbellifers are. The nice thing about a cranefly is that they generally don’t move far when spotted and will happily sit and have their photo taken.
The second cranefly species looked non-descript and was amongst the marshy area near No.4 tank. I just took a few snaps as a matter of interest to compare to the Tiger Cranefly. When I looked closely at the pictures, it was amazing they had an alien-like appearance around the head, with green eyes. I had to ask for help on this one and the Dipterists website came back with Tipula vernalis.
And so on to the last two species, for now and both easy to identify.
There was a big emergence of Garden Chafer Phyllopertha horticola (image above) across the marsh particularly in sandy areas and the beetles were seeking mates and were chasing one another. The larvae feed underground on grass-roots for three of four years before emerging as adults. They didn’t look so striking until I had a look at the pictures in close-up and then the green thorax and brown wing cases and the mass of hairs all over them made them a lot more interesting.
The last beetle has been mentioned in ‘Nature Notes’ previously but because this image makes it look even more beautiful as it feeds on a Buttercup, I thought it was definitely worth including. The beetle is a pollen feeder and are reasonably common across the marsh particularly on flowers such as umbellifers and buttercups. I give you…Swollen-thighed Beetle Oedemera nobilis. The males have the swollen thighs which give them their name. The polished metallic green is brilliant and you can even see my reflection on its thigh! Cheshire is on the northern edge of its range.
Written and illustrated by Tony Broome.
With grateful thanks to Phillip Brighton for help with the identification of the tricky species.