openness is more costly in terms of energy, and people with high parasite loads have less to spare. I don't know how you'd test that.

Correlate openness with other drains on energy, like non-communicable, non-immune-weakening disorders.

Unrelatedly, I'm still pondering the implications of Limbaugh-type demogagues characterizing illegal immigrants as parasites in evocative language. Probably just a priming thing they aren't even aware of, but it would seem to make their rhetoric more effective.