reply to post by silent thunder
Thank you for that very interesting information.
What we have here is an evolutionary arms race (yes, that's the technical term). Hosts always evolve defences against parasites; parasites, in turn,
must evolve means to overcome those defences. It's turn and turn about, generation upon generation.
Rarely does one party in an arms race overcome the other – and if one dies out, the other often does, too. Obviously, if the host species dies out,
the parasite, with its specialised adaptations, cannot survive. Less obviously, the extinction of the parasite species can lead to a Malthusian event
in the host population – without the parasites to cull them, the hosts increase in numbers until they outgrow their food supplies and suffer a
population crash, sometimes leading to their extinction.
In fact, there are some 'slave' species which would die out without their hosts, whose help they need to survive and reproduce. A famous example, also
from the ant world, is that of aphids or 'plant lice'. Some species of ant actually 'farm' aphids, helping them reproduce by storing aphid eggs inside
their nests during winter. Symbiosis is often no more than benign parasitism.
In the present case, the slave species has found a way to control the master species' population, but that is not the same thing as overthrowing the
master species. The slavers will evolve new defences in response to the threat. As the authors of the study say in
their original paper
, 'The parasite P. americanus
is now under strong selection to adapt its pupal recognition cues to
those of its hosts to counteract slave rebellion.' (p.48)
Evolution among animals has resulted in just about every social arrangement human beings have ever invented, plus a good many more. We ought to be
hesitant about drawing political, social or moral conclusions from them, because every example in nature has its counterexample.
edit on 28/9/12 by Astyanax because: Of grammar Gestapo agents.