30 years ago, biologists thought they’d solved one of Darwin’s
thorniest problems, the evolution of sterile social insects:
-Charles Darwin, On the Origin of Species  The apparent solution
to Darwin’s conundrum was an elegant formulation by W. D.
Hamilton. Genes can propagate themselves not only through direct
reproduction, but by assisting in the reproduction of other
individuals that carry the same gene. A worker ant may be
sterile, but she can give her fertile sisters a boost. Sociality
could evolve after all. This concept of increased fitness
through assisting one’s relatives is called kin selection, and
it was immediately popular among social insect biologists.  In
recent years, a number of scientists have challenged kin
selection orthodoxy with a rather fuzzy concept called “group
selection“, holding that kin selection cannot explain the advent
of social insects. One of their arguments is that social insect
colonies are often composed of individuals that aren’t closely
related. In many species, includ