Aceria macrorhyncha – You may have noticed these little bright red pustules on the upper surface tree leaves and wondered what they were? These are plant galls, and this one in particular is caused by a tiny mite ( they belong to the same group as spiders) which feed on the leaves of Sycamore (Acer pseudoplatanus). The mites are small enough to pierce and feed on individual plant cells, causing the surrounding cells to enlarge and multiply to form the gall. In the final image you can see the holes on the underside of the leaf, beneath the galls. Not sure what the red jelly-like stuff is. Double-click images for a closer look-see.
© Peter Hillman ♦12th May 2020 ♦ Local woodland path, South Staffordshire ♦ Nikon D7200
Nature Journeys 
Like too many things, I’ve honestly never looked closely at them. Thank you for sharing this.
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I only realised such things as galls existed a few years ago. They really opened my eyes up to a new world of discovery.
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Learned something new – thank you!
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You are welcome, Rebecca! Thank you.
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I saw them during a walk one day and had to check the reference. Interesting!
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That is exactly what I did some years ago 🙂
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Nice natural history lesson, Pete. Sort of hard to describe a gall as pretty but that red is attractive. The most interesting and attractive gall I have found is the Wool-Sower, a wasp.
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Thank you, Steve. I have always found them fascinating. Most people never know they are even there.
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Interesting, Peter. I’ve seen similar bumps on leaves, although not red ones, and wondered. Quite a reaction of the leaf cells to respond this way.
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I have always found plant galls fascinatining, especially in the way they trigger a change in the plant tissues.
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That is amazing! I don’t think I have ever seen this before. I had no idea .. thanks for this! The plants reaction sure is interesting!
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You are welcome, and thank you, Julie 🙂 Something to look out for in the garden or on your travels. I have always found the varied forms and the biology involved quite fascinating.
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