11 Wednesday Sep 2024
Posted in insects
Back at the start of August, I blogged about The weird & wonderful world of Sawfly larvae, which included two of the slug-like species Caliroa annulipes and Caliroa cerasi. Recently, I found another one, Caliroa cinxia, a larva that looks very similar to Caliroa annulipes but its front end – more accurately, its thoracic region – is much more yellow in colour. You can read more about it and see what the adult sawfly looks like on The Sawflies (Symphyta) of Britain and Ireland website.
01 Thursday Aug 2024
Posted in insects
Tags
British sawflies, Caliroa annulipes, Caliroa cerasi, Eriocampa ovata, Euura pavida, Nematus septentrionalis, sawfly larvae
I mentioned earlier in the week, in my post about the sawfly larva Heterarthrus vagans mining the leaves of Alder, that I’d found that miner while checking out leaves to see what small creatures had been munching holes in their leaves. And my recent staring at holey leaves on other trees and shrubs, in other locations, has produced a nice variety of Sawfly larvae, some that look like regular caterpillars, others like slimy slugs. I’ve linked the names to the Sawflies of Britain and Ireland website for those interested in more information on each species.
Caliroa annulipes on Hawthorn
Caliroa cerasi, also on Hawthorn
An unidentified Cladius species, on Field rose
The one that looks like bird poo, Eriocampa ovata, on Alder
One of the bum-waggling species, Euura pavida, on Willow
Another bottom waggler, Nematus septentrionalis, on Birch. I love how their munching has created a heart from their leaf.
24 Monday Jun 2024
Tags
British leafminers, British sawflies, leaf-mining sawfly larvae, leafminers on Birch, sawfly larvae on Birch
Staring at the leaves of young Birch trees paid off once again when I recently spotted these large blotches.
They were made by the larvae of Scolioneura betuleti, a small black sawfly – you can see a photo of the adult on The Sawflies of Britain and Ireland website. The larvae are active in early summer and again in the autumn – the British Leafminers website has images of the distinctive larvae.
25 Saturday Nov 2023
Posted in insects
Did you know that the sawfly gets its name from the way it lays its eggs? Innocuous little flies, like the beauty shown below (Arge pagana, one of the UK species that uses the rose as its larval plant), have an in-built saw-like body part that they use to cut a slot in their larval plant material and in that slot they lay their eggs.
On some plants, like the stems of the various Rosa species used by Arge pagana, the slot leaves quite a substantial scar and, this week, for the first time, I noticed one of these when checking Dog roses for leafmines. As you can see, there’s a healthy leaf bud right next to the scar so the plant doesn’t seem to have been damaged by the slot-making process, though the voracious larvae that hatched from the eggs earlier in the year may well have stripped the rose of many of its leaves.
06 Friday Oct 2023
Another day, another Cladius sawfly – actually, this time, 6 sawfly larvae, all munching away on the leaves of a Field rose. I was hoping their identification would be as easy as yesterday’s Cladius ulmi, with its distinctive black-spotted face, but no!
This time my expert confirmed it was definitely a Cladius species and that my guess of Cladius pectinicornis was the most likely but C. pilicornis and C. compressicornis also use rose as their larval plant of choice. When I consulted The Sawflies (Symphyta) of Britain and Ireland website I found for C. pilicornis that the only larva shown on the website had a broad dark stripe down its back and the text said the larvae associated with Hawthorn, not rose, so that seemed unlikely. However, when I checked C. compressicornis, it did look to be a likely contender, with features and larval plants very similar to C. pectinicornis.
So, once again I have to concede that I can’t put an exact name to these very cute little sawfly larvae, but I certainly enjoyed watching them. When much in the world around us seems maddening and/or depressing, I find there’s something very calming about watching caterpillars eating and gliding about.
05 Thursday Oct 2023
Tags
British sawflies, Cladius sawflies, Cladius ulmi, Cladius ulmi larva, sawfly larva, sawfly on Wych elm, Wych elm
There are just seven species of Cladius sawfly found in Britain, which, you might think, would make them relatively easy to identify. Sadly, this isn’t the case, especially in their larval forms, as all their caterpillars look very similar, and even the expert I consulted said he was unsure about the larval differences.
However, I seem to have struck it lucky with this particular species as The Sawflies (Symphyta) of Britain and Ireland website says: ‘They can be distinguished from the other elm feeding species, Cladius rufipes, by the presence of a black spot on the front of the face which is absent in rufipes.’ As you can clearly see in the photo above, this larva has that black spot, so meet Cladius ulmi, a sawfly species that feeds on elm, in this case Wych elm (Ulmus glabra).
13 Wednesday Sep 2023
Tags
British sawflies, Euura pavida, Euura pavida larvae, Nematus pavidus, sawfly larvae, sawfly on willow, willow, willow species
After last week’s heatwave (which kept me indoors a couple of days – I do NOT like the heat!), Monday’s walk was deliciously cool, if a little damp from un-forecast rain, and, even better, I found two new-to-me creatures. The first was a new species of sawfly larvae that I spotted when I saw this barely-there leaf. I’m always curious when I see leaves like this to find what has caused the damage.
It didn’t take long to find the culprits this time – at least 20, possibly more, hungry larvae munching the tough leaves of a willow species right down to their veins.
Previously known as Nematus pavidus, their species name has now changed to Euura pavida. The larvae are usually found chewing on willow leaves but can also be found on Alder and Poplar. You can see what the adult sawfly looks like on The Sawflies (Symphyta) of Britain and Ireland website.
23 Wednesday Aug 2023
Tags
Birch, British sawflies, Nematus septentrionalis, sawfly eggs, sawfly larvae, sawfly larvae on Birch, sawfly on Birch
The sawfly larvae are back!
You may remember my post last summer (Sawfly larvae on Birch, July 2022) about the black-spotted yellow-and-green larvae of the sawfly Nematus septentrionalis that were munching through the leaves of a local Birch sapling. Well, luckily, the sapling survived but it’s now providing a feast for this year’s brood of the same sawflies.
This time around I’ve found the larvae at a much earlier stage of development. And, destructive though they may be, they do look rather cute curled up in their individual holes in the leaves, and quite different in colour at this young age.
Plus, this time I spotted the eggs they emerged from – and some eggs yet to hatch, laid by the adult sawfly along the veins of the leaves.
I may sound a trifle over-enthusiastic about creatures that are basically eating a tree. But, last year, something ate most of the larvae before they consumed too many leaves and, as there are a good number of hungry Stonechats, Whitethroats, Green- and Goldfinches currently in this field, I think the sawfly larvae’s days are probably numbered.
12 Wednesday Apr 2023
Meet Nematus lucidus, a sawfly that can be recognised both by the reddish-brown markings on its mostly black body and the torpedo shape of its abdomen.
Nematus lucidus can be seen around Blackthorn and Hawthorn, as those are the plants its larvae feed on, and the adults can be seen any time from April to June. It’s thought to be common though there aren’t a lot of records in the national databases, probably because it’s under-recorded.
21 Thursday Jul 2022
Posted in insects
Tags
British sawflies, Sawfly, Tenthredo arcuata/brevicornis/notha/schaefferi agg., Tenthredo sawflies
Have you ever wondered why the abbreviation ‘agg.’ is used after the scientific names of some flora and fauna? Well, this particular sawfly is a prime example.
‘Agg.’ is short for aggregate and is used where there exists a group of species that are so closely related and difficult to distinguish from each other, that for practical biodiversity recording purposes they are considered one species. As the Nature Spot website explains
The four species within the Tenthredo arcuata complex are problematic to distinguish and the species boundaries are unclear. The complex within Britain and Ireland consists of the species T. arcuata, brevicornis, notha and schaefferi. Unless specimens have been microscopically examined by someone with suitable expertise, we have decided that they should be recorded as part of this aggregate.
So, the scientific name used for this rather cute little sawfly is quite a mouthful: Tenthredo arcuata/brevicornis/notha/schaefferi agg.
earthstar 
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