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Marchant, James

"Alfred Russel Wallace: Letters and Reminiscences, Vol. 1"


Or perhaps the _protection_ is acquired because this tendency exists. I
admit therefore in the case of concealed nests they [habits] may have
been acquired for protection.
Now for the special case.
7. In the very weak-flying Leptalis both sexes mimic Heliconidae.
8. In the much more powerful Papilio, Pieris, and Diadema it is
generally the _female only_ that mimics Danaida.
9. In these cases the females often acquire more bright and varied
colours than the male. Sometimes, as in _Pieris pyrrha_, conspicuously
so.
10. No single case is known of a male Papilio, Pieris, Diadema (or any
other insect?) _alone_ mimicking a Danais, etc.
11. But colour is more frequent in males, and _variations_ always seem
ready for purposes of sexual or other selection.
12. The fair inference seems to be that given in proposition 5 of the
general argument, viz. that _each species_ and _each sex_ can only be
modified by selection just as far as is absolutely necessary, not a step
farther. A male, being by structure and habits less exposed to danger
and less requiring protection than the female, cannot have more
protection given to it by Natural Selection, but a female must have some
extra protection to balance the greater danger, and she rapidly acquires
it in one way or another.


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