The bees would teach Thanos how stupid his idea was by surviving year after year, because cutting a population in half does almost nothing. This is one of the things that have irked me the most about the Avengers movies, they propagate his idea as somehow making any sense at all, when in fact it is doing a great disservice to the world by not teaching them about populations and use of resources. A reduction of the universe's population by half would be made up for quite quickly as if nothing had ever happened and billions or trillions slaughtered for nothing. In cancer treatment you usally need at least a log kill or preferably multiple log kills to affect change. A better snap of fingers would have probably been to teach the universe to use less and recycle more or teach how to use contraception.

https://www.endurocide.com/knowledge-base/blogs/log-reductio...

http://www.d.umn.edu/~jfitzake/Lectures/DMED/Antineoplastics...