Consider the locust who, alone, does no harm, but devastates the earth when part of a swarm. They mass and devour fruit grain and leaf without thought of the future; it beggars belief.
Then sated and full they all die en mass as ultimate victims of their voracious repast.
Consider the human being who, alone, does no harm...
7.7 billion humans on the way to 10 billion by 2050 Pity the Earth