parasites outnumber hosts

By anywhere from 10:1 to 1000:1, and, collectively, outweigh the biggest predators in the food web. NewScientist reports:

Put together, the parasites in each estuary weighed as much as the local fish and between 3 and 9 times more than the local birds. Parasites that "castrate" their hosts – prevent them from reproducing – had the greatest cumulative biomass and on their own weighed as much as the local winter birds.

For Andrew Dobson of Princeton University, one of Kuris's collaborators, this shows that that castration is the most effective way for parasites to survive. Castration allows parasites to keep the hosts alive while preventing them from spending any energy on their own reproduction.

I will resist all urges to draw an anthropomorphic conclusion.