K is for Knopper

16 Saturday Dec 2023

Posted by sconzani in insects, plants, trees

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British galls, bug galls, galls, galls on Ash, galls on Hazel, galls on oak trees, galls on Poplar, galls on willow, galls on Yew, Knopper gall, midge galls, mite galls, wasp galls

This is really a review of the galls I’ve found this year but the letter G simply had to be about my first ever confirmed Goshawk sighting, so K is for Knopper is my alternative lead in.

231216 Knopper Andricus quercuscalicis

Knopper galls, like the one shown above, did feature in one post this year, Acorns and galls on 1 October, but there were many other galls, most of which were new finds for me. February saw the year off to a good start with galls on Yew trees caused by a tiny midge (Galls: Taxomyia taxi, 9 February) and galls on Hazel caused by an equally tiny mite (Galls: Phytoptus avellanae, 20 February). In June, it was a small bug that was creating eye-catching galls on the leaves of an Ash tree (Galls: Psyllopsis fraxini, 12 June), and, in July, aphids were the gall causers on a Poplar tree (Galls: Pemphigus spyrothecae, 17 July). In that October blog Acorns and galls I mentioned above, as well as the knoppers, another tiny wasp had caused artichoke galls to form on the same Oak tree. And, a couple of weeks later, I found my final new galls for the year, those caused by midges on Willow trees (Galls: Rabdophaga rosaria, 17 October). All in all, 2023 was quite a galling year!

231216 mixed galls

268/366 Gone galling

24 Thursday Sep 2020

Posted by sconzani in insects, trees

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Common spangle gall, gall wasps, galls on oak trees, Knopper gall, Marble galls, oak galls, Oyster gall, Silk button galls, Smooth spangle galls

I wanted a relatively short walk between rain showers so headed to a small local green belt where Oak saplings were planted a few years ago, and my wander turned into a challenge to see how many different types of gall I could find in just this one small copse of young Oaks. The answer? Six!

First up, Knopper galls, caused by the wasp Andriscus quercuscalicis. For more on that gall, see my August 2017 post Oak galls: knoppers and artichokes.

Next, Marbles, which I covered in Oak galls: marbles and apples, August 2017.

Then, I found some Common spangles (below left), caused by the wasp Neuroterus quercusbaccarum. More on that mouthful in Oak galls: currants and spangles, August 2017.

You may have noticed my photo of Marble galls also had something else on the leaves. These were Smooth spangles (above right), a product of the wasp Neuroterus albipes.

I covered both Smooth spangles and this next gall, the Oyster, in the same blog: Oak galls: spangles and oysters, September 2017. The photo on the left above shows Oysters just beginning to form on the spine of the leaf; the one on the right shows two more developed examples, both on the same tree.

And, last but most certainly not least, as there were thousands of these on all the Oak trees I looked at, Silk button galls, caused by the wasp Neuroterus numismalis. I wrote about those in Oak galls: ram’s-horns and silk buttons, September 2017.

Not a bad haul for an hour turning over leaves and peering amongst branches. I didn’t find examples of all the Oak galls I’ve found before but I was very happy with this sampling.

249/366 Small creatures after rain

05 Saturday Sep 2020

Posted by sconzani in autumn, insects

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beetles, British insects, Brown-tail moth caterpillars, Brown-tail moth webs, Buff-tailed bumblebee, Emperor dragonfly, Knopper gall

Actually, it rained before my walk, during my walk and after I got home, but ‘Small creatures between showers’ was a bit long for a title. Here, then, are the said creatures …

200905 beetles

First up, these beetles were cosying up in an umbellifer flower head. I couldn’t see enough to identify them and wasn’t going to disturb their comfort to find out more.

200905 brown tails

This is a web of Brown-tail moth larvae, the ones some people freak out about because their hairs can irritate the skin. The solution to that problem is, of course, easy: look, enjoy, wonder, admire, but don’t touch!

200905 buff-tail queen

There weren’t many flying critters about but bumblebees will fly whatever the weather, as shown by this gorgeous queen Buff-tailed bumble.

200905 knopper gall

Perhaps the littlest creature, though I didn’t look in to investigate, was the one that was lurking in this Knopper gall (spot the antennae!).

200905 emperor

And, the prize for the most magnificent, was this male Emperor dragonfly. I had to linger a while, waiting for him to settle, and then sneak up behind the bushes, but His Imperial Majesty was definitely worth the wait. What a handsome creature he is, despite his somewhat ragged wings.

Oak galls: knoppers and artichokes

23 Wednesday Aug 2017

Posted by sconzani in insects, nature, trees

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Andricus foecundatrix, Andriscus quercuscalicis, Artichoke gall, galls caused by wasps, galls on oak trees, Knopper gall, oak galls, Oak hop gall, oak tree, Pedunculate Oak, Quercus petraea, Quercus robur, Sessile oak

Following quickly on from yesterday’s oak galls, part 1, we have oak attack, part 2, a sorry tale of knoppers and artichokes – and, no, you can’t eat them!

170823 Andricus quercuscalicis Oak knopper gall (2)

170823 Andricus quercuscalicis Oak knopper gall (1)

First the knoppers, which are caused by Andriscus quercuscalicis, a wasp with chemical weapons. The wasp lays its eggs in buds on oak trees and the larvae, when they hatch, secrete a chemical that causes the developing acorn to distort into a knobbly lump, thus forming a home for themselves. The galls are structurally interesting but not so good for the oak tree, as the acorn is no longer a viable seed for the tree and I presume the knopper gall also makes the acorn unsuitable as food for wildlife as well. Apparently, this wasp only arrived in Britain in the 1960s but its spread has been rapid, with the galls now found throughout Wales and England and in southern Scotland, though only on the Pedunculate oak (Quercus robur).

170823 Andricus foecundatrix Oak artichoke gall (1)

170823 Andricus foecundatrix Oak artichoke gall (2)

170823 Andricus foecundatrix Oak artichoke gall (3)

Artichoke galls – also known as hop galls due to their resemblance to flower of the hop plant – are also the result of chemical distortion by a wasp. This time it’s Andricus foecundatrix that does the damage. Using its sharp ovipositor, it lays its eggs in the leaf buds of both the Pedunculate oak and the Sessile oak (Quercus petraea). Like yesterday’s Spangle-causing wasp, Andricus foecundatrix also has both a sexual and an asexual generation. The asexual wasp hatches from her artichoke home in the springtime and lays her eggs in oak catkins, causing a small oval-shaped gall to develop – I don’t yet have any photos of these galls but you can see images here.