Why do ants survive in a microwave oven?

Being small keeps the ant close to the conducting metal plate at the base of the oven where the amplitude of the microwaves is minimal. I am not sure whether the ant is able to utilise the interference pattern set up by the microwave sources, but it would if you stopped the plate rotating. In addition the ant has a low fat / water content to minimise energy adsorption and high surface area to body mass ratio which aids heat loss. In addition ants can tolerate high body temperatures (above 50C) and desert species are able to remain active during the daytime.