The tiny cynipid wasp Neuroterus quercusbaccarum lays its eggs on the underside of the leaves of various oak species. The resulting larvae grow inside protective shelters connected to the leaf by a short stalk, familiar to many people as the spangle gall. When the leaf falls to the ground in the autumn, the larvae remain protected and overwinter inside the gall. They hatch as adult wasps in summer and fly off to seek a mate, the females finding an oak leaf on which to lay a clutch of eggs. In ecological terms, the cynipid wasp has an amensal relationship with the oak tree, just as we do, as humans. Amensal describes an association between two species where one is dependent on the other for its survival, but this is not the case the other way round. Trees not only provide us with clean air and water, give us shade and protect our soils, but their products can help us live more sustainably, and they are important for our mental health and wellbeing. In return, trees receive nothing.
All photos (c) Gabriel Hemery