very fun to play ! I like the concept.
I think I broke the game xD. 
It happens with the auto deploy after clicking very fast to have 0 ants left, then going in the upgrade menu. When exiting the menu it can deploy an ant and the value is set negatively.
I think there is a delay between the condition check "if(ant != 0)" of the auto deploy and the counter
with the spawn of the ant.
I'm not sure at 100% it is exactly what happened but I think it's that logic which trigger the funny thing. Anyways, that was fun !