Giant Wings: Why Paleozoic Insects Got So Large
Giant insects like Meganeura and Meganeuropsis lived in the Carboniferous and Permian when atmospheric oxygen was higher, which may have supported their large bodies and wings; another idea is that very high oxygen could be toxic but larger size diluted its effects, and a lack of serious aerial predators at the time allowed these insects to dominate the skies — suggesting a mix of ecological and physiological factors behind their gigantism.