- One of the most fundamental differences between animals are size differences that are often prominent when comparing species, as well as the sexes within species. One important aim of evolutionary and ecological studies is therefore to understand the pattern of size variation.
- Bergmann's rule and Rensch's rule are two ideas that describe such general patterns. But whether or not these rules apply only in homoeothermic animals, or also in insects, is unclear because previous studies have shown opposing results.
- For two subspecies of Poecilimon veluchianus Ramme (Orthoptera: Tettigoniidae), we demonstrate a pattern that is opposite to what is predicted by Bergmann's rule. Rensch's rule also does not seem to apply, as sexual size dimorphism (SSD) does not change even though body size decreases with elevation in these two taxa. Our data adds to an emerging pattern that the two rules are not universally applicable in insects.