The Limits of Insect Enlargement

If an ant, or a mantis, were to be magically scaled up to the size of a human, it would end up dying very quickly of its own accord, well before it could be a real threat (as would happen to Antman for similar reasons). An insect’s respiratory and circulatory systems, as well as thermoregulation, would not, all environmental conditions being equal, allow it to survive long by growing beyond certain sizes, much less act hostile.