Wild discoveries - Braeburn Park - Robin's Pincushion

This hairy growth found on the stem of Dog-rose is the old gall of a small wasp (Diplolepis roase). This structure is created when a wasp lays its eggs inside the buds/developing leaves of the Dog-rose. The larvae secrete chemicals that cause the plant to grow this abnormal structure (the gall) rather than buds or leaves. The larvae then develop within the structure over winter, emerging as adults in the Spring. You can see the exit holes in this image! Galls come in all sorts of bizarre shapes and sizes and are found on lots of different plants. They can be caused by many organisms including other insects, mites, bacteria, fungi, and viruses and are not usually detrimental the plant.