NEN Gallery

Oak Apple Galls are found where ever oak trees grow. They are green at first, turning brown later. Female gall wasps burrow into the soil at the base of oak trees and inject eggs into the roots. Wasp larvae hatch and for over a year feed on the roots before becoming pupae. Wingless female wasps hatch from the pupae underground, crawl out of the soil and up the tree trunk in early Spring. They inject an egg into the mid-rib of a newly growing leaf. The larvae that hatch inside the leaf are small and round. As they grow, they cause a chemical reaction inside the leaf that forms a gall around the larvae. The gall itself is actually a mutated leaf. Each larva continues eating and growing, and the apple gall grows with it. Picture taken 5th May 2006 at Old Warden, Bedfordshire.