Monarch butterflies help explain why parasites harm hosts

It’s a paradox that has confounded evolutionary biologists since Charles Darwin published On the Origin of Species in 1859: Since parasites depend on their hosts for survival, why do they harm them?

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<p><a href="http://www.physorg.com/news129983011.html">Monarch butterflies help explain why parasites harm hosts</a></p> <p>It’s a paradox that has confounded evolutionary biologists since Charles Darwin published On the Origin of Species in 1859: Since parasites depend on their hosts for survival, why do they harm them?</p>