From Phill Chadwick
Sharon Basson asks what could disorient mayflies so much that they confused
mirror glass with expanses of water, and attempted to lay eggs on vertical windows
(Letters, 19 September, p 55).
In evolutionary terms, there’s no reason why mayflies need to know that water
is usually horizontal. The only substantial expanse of shiny, reflective
material would have been a body of water, so “shiny, flat and fairly extensive”
was good enough.
It is only in the past few hundred years that we humans have been creating
vertical and horizontal river lookalikes, tricking the mayflies.
Erindale, South Australia
