Stranger Than Fiction
Many insects have bizarre genitalia - the mouldable
chitin that makes up insects' outer body is a versatile
building material for imaginative forms. Dragonflies,
for example, have structures like brushes, pipe cleaners
and inflatable beach balls that scoop out rivals'
sperm. "It's stranger than fiction," admits Siva-Jothy.
Paired penes, though common in spiders and crustaceans,
are rare in insects, says sexual-selection researcher
William Eberhard of the University of Costa Rica.
The earwigs' double whammy may be an ancestral throwback
- like antennae and legs, Penises were originally
paired.
Why insects evolved such a diverse repertoire of genitals
nevertheless remains a bone of contention. As well
as being adapted to ensure that sperm is successful,
Eberhardt argues, insects' members may have been influenced
by female taste. "Females discriminate amongst males
on the basis of their genitalia," he says.
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