Social insects are best known as exceptions to the general rule that relations between individuals are competitive. They have evolved social organizations that are so harmonious that the colony itself is often considered a single individual, or "superorganism", for purposes of biological study. In an article in the April 12 issue of Science, David C. Queller and Joan E. Strassmann propose that social insects may also provide extraordinary exceptions to another general rule: that relations within individuals are completely harmonious.
The suggestion grows out of theories that aim to explain possible genetic conflicts between the genes that individuals receive from their mothers and fathers. For mom's and dad's genes to battle it out requires both means and motive. Until recently, the means were thought to be absent because genes could not tell which parent they came from. However, this "veil of ignorance" is sometimes lifted through a process called "imprinting" in which mothers and fathers label some of their genes before passing them on to their young.
The "motive" comes, as always in evolution, from how genes best reproduce themselves. In the classic mammalian case of imprinting, paternally derived genes strive to create a large placenta that favors the developing child -- who carries the fathers genes -- over the health of the mother -- who doesnt share the paternal genes. Maternally derived genes favor a smaller placenta that would protect the mothers health and her ability to produce future offspring who will carry on her genetic line.