Primarily though, it was probably a highly efficient hunter of smaller aerial insects such as primitive flies. Even so, it could have taken reptiles the size of Petrolacosaurus. Meganeura, like all of the oversized 'creepy-crawlies' of the Carboniferous, was allowed to evolutionarily attain such extraordinary size because of the presence of 3 times the level of Oxygen (O2) in the atmosphere back then in the Carboniferous Period in which it lived, than there is in the Present Day.
This meant it required much less energy to move and support ones weight, and perhaps means that things moved relatively faster under the Laws of Motion also - a jumping human that could say reach a metre off the ground in the Present Day, may have if this person theoretically went back to the Late Carboniferous Period of 300 Million Years Ago in the time of Meganeura, reached a height of 3 metres with the same expenditure of effort. An interesting thought indeed. Meganeura is thought to have lasted from 320-280 Million Years Ago - becoming extinct by the Early Permian, along with a great many other monster Insects and other Arthropods, due to the global drying of the climate and loss of oxygen levels, leading to the aridification of the once lush swamp forest world of the Carboniferous Period.
Walking With MonstersEdit
Meganeura is featured in the second episode of Walking With Monsters.