A Cladius on Wych elm

05 Thursday Oct 2023

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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.

231005 Cladius ulmi (1)

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).

231005 Cladius ulmi (2)

Leafmines: Bucculatrix bechsteinella

02 Monday Oct 2023

Posted by sconzani in insects, trees

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British leafmines, Bucculatrix bechsteinella, Hawthorn bent-wing, leafmine on Hawthorn, moth leafmines

This is another of my ‘I think it might be this but it might not be’ posts. One of the people I follow on Twitter (I refuse to call it X) has begun sharing a ‘Lepidoptera leafmines to find’ monthly post, and one of this month’s six is Bucculatrix bechsteinella, found on Hawthorn.

231002 bucculatrix bechsteinella (1)

The post warns that Bucculatrix bechsteinella (also known as Hawthorn bent-wing) ‘may be confused with those of Paraswammwerdammia nebulella, which tend to be smaller, more numerous and with irregular exits and occurring anywhere on the leaf, but those of B. bechsteinella usually occur in a vein axil.’ This description leads me to think my finds are correct but I’ll need to await verification of my records to be sure. (You can see the adult moth on the UK Moths website.)

231002 bucculatrix bechsteinella (2)

Acorns and galls

01 Sunday Oct 2023

Posted by sconzani in autumn, insects, trees

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acorns, Andricus foecundatrix, Andriscus quercuscalicis, artichoke galls, British galls, gall wasps, galls on acorns, galls on oak trees, knoppers, Oak gall wasps, Oak trees

I was taking photos of acorns, thinking I’d perhaps write a blog about the many varied types of nuts, when it occurred to me how many galls I’ve been seeing on acorns this year. The gall-causers are having a good year.

230930 acorns (1)

I’ve covered these before (in Oak galls: knoppers and artichokes, August 2017) so won’t repeat myself here. But if you’re interested in what causes these particular galls, just click on the link to that previous blog. The galls in the first photo are Artichoke galls, caused by the tiny wasp Andricus foecundatrix, and the galls in the second photo, which have almost totally consumed the acorns, have been caused by another wasp Andriscus quercuscalicis.

230930 acorn galls (2)

A parasitised aphid

19 Tuesday Sep 2023

Posted by sconzani in insects, trees

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aphid on Oak, aphid parasitised by wasp, leaf-turning, oak aphid, parasitic wasp, parasitic wasp on Oak, Praon, Praon wasp species

*** This post has been edited to correct previously wrong information. ***

I’ve seen these odd sights previously but only recently learned what they were and have been searching for an example to show you since then. Finally, during last Friday’s walk, with a little Oak-leaf-turning, I found another. Unfortunately the light wasn’t great so my photos aren’t as crisp as I would’ve liked but hopefully you’ll get the idea.

230919 tuberculatus parasitised by Praon flavinode (1)

The creature is an aphid, most likely a Common oak aphid (Tuberculatus annulatus), but my poor photos mean I can’t be sure of that. The aphid has been parasitised by a tiny wasp that has laid its egg inside the aphid’s body. When it hatches, the larva cuts a hole in the aphid’s body and spins silk to attach itself and its host to the leaf. Then, once it has sucked the life out of the aphid and grown sufficiently, the wasp larva builds its cocoon beneath the aphid – I guess the aphid’s body acts as camouflage and protection for the wasp pupa.

230919 tuberculatus parasitised by Praon flavinode (2)

The Praon genus of parasitic wasps are the only ones that create this puff-pastry-like attachment beneath their host, and, according to a local expert I’ve consulted, this is likely to be the species Praon flavinode, which is known to parasitise aphids on Oak and Birch. I’ve a mind to try to find another of these and, if the adult wasp hasn’t emerged, bring it home, put it in a jar and wait to see what emerges. Watch this space!

Euura pavida

13 Wednesday Sep 2023

Posted by sconzani in insects, trees

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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.

230913 euura pavida (3)

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.

230913 euura pavida (2)

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.

230913 euura pavida (1)

Imperfect concealment

12 Tuesday Sep 2023

Posted by sconzani in birds, trees

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birding, birdwatching, British birds, Green woodpecker, Hawthorn, Hawthorn berries, red berries

Is it a canny eye for detail or simply good luck that both these Green woodpeckers chose Hawthorn trees bedecked with red berries to perch on?

230912 green woodpecker (1)

The combination of green leaves, red berries and beige-ish bark and branches is almost a perfect match for the joyful colours of the birds but, if this is an attempt at camouflage, though they haven’t quite nailed it I’d give them an eight out of ten for effort.

230912 green woodpecker (2)

Nematus septentrionalis

23 Wednesday Aug 2023

Posted by sconzani in insects, trees

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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.

A White-letter hairstreak

22 Saturday Jul 2023

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British butterflies, butterfly, butterfly in Wych elm, White-letter hairstreak, Wych elm

Last Saturday’s weather was rather different to today’s constant rain – there was rain, but interspersed with warmer, sunny spells, and I managed to coincide my visit to local Dingle Park with one of those. This was my third time standing staring at the park’s Wych elms, and it was definitely a case of third time lucky.

230721 white-letter hairstreak (1)

Previously, the White-letter hairstreaks had stayed high in the tree but, this time, one little beauty came down lower, wandering slowly across the leaves, all the while with its tongue out, licking up the tasty honey dew.

230721 white-letter hairstreak (2)

Initially, it was quite distant but my patience paid off as it flitted from one cluster of leaves to another until it was really quite close. White-letter magic!

230721 white-letter hairstreak (3)

Purple sheen

21 Friday Jul 2023

Posted by sconzani in insects, trees

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British butterflies, butterflies in oak trees, butterfly, Purple hairstreak

First I saw one distantly in the Oak trees opposite Lavernock Nature Reserve, and I was glad.

230721 purple hairstreak (1)

Then I saw one very close in the Oak trees at Casehill Woodland (as it flitted right on to the leaves in front of me), and I was overjoyed.

230721 purple hairstreak (2)

They’re Purple hairstreaks, of course, and they are beautiful, and I was very lucky.

230721 purple hairstreak (3)

Poplar hawk-moth larva

18 Tuesday Jul 2023

Posted by sconzani in insects, trees

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British moths, caterpillar on Poplar, Laothoe populi, moth caterpillar, Poplar, Poplar hawk-moth, Poplar hawk-moth larva

The leaf-staring story I related yesterday didn’t end with me seeing my first Poplar spiral galls – oh no! There was a bonus sighting that was much more exciting. Lurking behind one of the leaves I turned to more easily photograph a gall was this caterpillar, the larva of a Poplar hawk-moth (Laothoe populi). What a magnificent beast it was!

230718 hawk-moth poplar