what's sex for? II

each bdelloid rotifer lives on the brink
because its genes are everywhere the same
the clone as one could quickly go extinct
and abstinence would have to be to blame
the Red Queen's Race is always neck and neck
as pathogens and hosts have to compete
so most ditch half our genes each round of sex
to keep a few contenders in the meet
a mammal unlike them exists in flux
our alleles are--at best--semiconserved
but so are those of whomever he fucks
the fittest--over eons--will be served
but changeless rotifers, windborne like seed
forsook the carnal pleasures of the deed