Very fly

Wilbur Hot Springs in Colusa County, California, is home to a unique species
of brine fly. Why is this fly so fussy, when a similar species is spread clear
across western North America? John Spicer and Kevin Gaston explain in
Physiological Diversity and its Ecological Implications that the answer
lies in their differing physiology: only the cosmopolitan cousin can cope with a
range of salt concentrations. At long last, scientists are beginning to solve
the puzzle. Published by Blackwell Science, £29.50, ISBN 0632054522.