BrownhillsBob's #365daysofbiking

On a bike, riding somewhere. Every day, rain or shine.

Posts tagged ‘parasites’

#365daysofbiking Sick more?

September 5th – Whilst I obsess over galls on oaks and wild roses, other shrubs and trees have their own problems. Here on Clayhanger Common, this sycamore tree is affected by sycamore mites and tar spot fungus.

The curious leaf growths form on the leaf like a gall from the point at which mites feed on the leaf by the same mechanism that other gall insects imply – in the case of these tiny mites, their saliva corrupts the lead cell DNA to grow into a gall.

On the underside of the leaf, a tiny, fur lined aperture into the gall is used by the mite after it has grown to lay its eggs, and the gall is eaten by the hatchling.

This leaf also has tar spot fungus.

Neither harm the host tree to any extent.

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#365daysofbiking Interdependence

September 2nd – The Darlaston Robins Pincushion Galls are looking really amazing right now – the one on the main ‘trunk’ (stalk? Branch?) of the wild rose is the largest I’ve ever seen, and still growing – now the size of a tennis ball, but elongated. On the outer leaves, the one that clearly misfired across multiple leaf nodes is causing odd, isolated patches of gall growth on leaves and twigs that look almost tumourous in nature.

This is an absolutely fascinating thing and I make no apologies for regularly featuring it. This is part of the wasp gall’s lifecycle and it’s absolutely stunning that such a tiny insect should co-opt and corrupt the growth of a plant to create such a host for its larva.

Amazing stuff.

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#365daysofbiking Corruption

August 21st – My goodness, this is strange.

Y’all know I love and am fascinated by insect galls, right? Well the robins pincushion galls on the wild rose I’ve been watching grow for weeks just took an odd turn.

There are several galls on the same rose now, the only plant in the thicket to be affected. Most of the galls are large, colourful and dramatic. But one weedy little on at the end of a twig seems to have got into a bit of a mess.

The photo isn’t great, but one can see that corruption from the implanted wasp egg has not been concentrated in one leaf node; it’s spread to several and there are bright red patches of furry spines all over the adjacent leaves.

Wonder what went wrong there?

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#365daysofbiking From little acorns

July 15th – More galls: I mentioned knopper galls recently and pointed out these wasp galls deform acorn buds to form a home for the wasp larva within. I found an illustration of this in Victoria Park Darlaston.

This is a knapper gall starting to form. The acorn cap is normal, but where the smooth, rounded nascent acorn should be, there is a knobbly, textured growth which will expand to form the gall.

The DNA of the acorn has literally been corrupted or reformed to grow a home for the wasp egg within by a chemical the egg was coated with.

How does such a mechanism evolve? It’s truly wonderful.

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#365daysofbiking Galling:

October 17th – I’ve been casually interested into the decomposition of the robin’s pincushion gall I found in the summer in Darlaston.

This once beautiful red and green hairy, spiny gall – created by a tiny wasp laying it’s DNA corrupting eggs in the rose leaf buds of it’s host – is now decaying fast and I’m interested to see how this ball of plant matter wastes away, and if it shows any evidence of the adult gall wasps escaping to freedom.

I’ll never stop being fascinated by these things.

July 13th – I’m sad to see the huge horse chestnut trees on Stafford Park in Telford are suffering for the first time I think with leaf miner parasites. 

These tiny larva destroy the leaves of the host tree from within, and although leaving the host pretty much unharmed, they bring on an ‘early autumn’ but causing the leaves to become blotchy and brown.

It looks worse than it is, but it’s a sad end to the season for many a beautiful tree.

Hopefully the current wave of these insects will pass soon.

June 29th – Spotted on the cycleway near Telford station, this oddly tortured oak tree. Generally with a healthy appearance, look closely and the tree is covered in insect galls, whereas the acorns that it has grown are oddly mutated and tiny. The leaves also seem subject to some kind of leaf miner attack.

I feel sorry for the oaks – they seem far more susceptible to such attacks and diseases than other trees. I’m not arborialist – is there a reason why the noble oak suffers so very much?