Common Spangle Gall

<em>Neuroterus quercusbaccarum</em>, commonly known as the common spangle gall, is a small gall wasp in the family Cynipidae, closely associated with oaks in Europe and western Asia. This species is notable for its complex life cycle involving alternating sexual and asexual generations, each producing morphologically distinct galls on its oak hosts. The asexual generation typically induces flat, disc-shaped "spangle" galls on the undersides of oak leaves, while the sexual generation produces small "currant" galls on oak catkins and leaves in spring. <em>Neuroterus quercusbaccarum</em> is widely distributed across Europe, extending into parts of western Asia and North Africa wherever suitable oak hosts, particularly <em>Quercus robur</em> and <em>Quercus petraea</em>, occur. The species has not been evaluated under IUCN Red List criteria, and population trends are not formally monitored, though it remains common across much of its range. Biological traits such as average lifespan in years, body dimensions, and weight remain poorly documented in the scientific literature for this minute insect. The larvae develop entirely within gall tissue, feeding on plant nutrients provided by the gall structure they induce. Adult wasps are free-living and do not feed substantially. Conservation status is listed as Not Evaluated.