In the jungles in the far-east, mosquitoes were a terrible problem. But one Commanding Officer used to sleep without his shirt in the open. The new chaps asked one of their more experienced seniors, "Doesn't he get bitten by those mosquitoes ??"
The chap answered, "Well, the C.O. has a bottle of whiskey before turning in. So, until 3 AM or so, he is too full to bother about the mosquitoes. By that time, the mosquitoes are too full to bother him!"