Researchers from three universities have measured more than 19,000 tropical moths from 1,100 species to find out whether their size varies with elevation. “Body size plays a central role in the ecology and evolution of organisms,” explains Dr Gunnar Brehm of the University of Jena. Moths from two extremely species-rich families ( Arctiinae (tiger moths) and Geometridae (geometer moths)) increase in size significantly at higher elevations. This matches expectations under the ‘Bergmann rule’. However, this rule was originally laid down only for birds and mammals, and the situation is different for cold-blooded animals such as insects. “We had actually presumed that these animals would become smaller at higher elevations,” adds Brehm.
