Elevational variation in voltinism demonstrates climatic adaptation in the dark bush‐cricket

Abstract

1. Phenotypic plasticity and/or genetic adaptation may allow species to live in a variable environment. It has been shown that eggs of the dark bush‐cricket, Pholidoptera griseoaptera , which experienced an insufficient warm treatment (shorter and/or colder), had a longer development time and hatched predominantly after the second diapause. 2. Given the broad distribution of this species from sea level to the timber line, we expected variation in voltinism along a climatic gradient. To reveal the role of natural selection in egg‐hatching patterns, we compared different and unrelated populations sampled along a 1000 m elevational gradient in a common laboratory experiment. 3. In the same rearing microclimate, we found that populations from mountains had mostly a shorter life cycle, whereas semivoltinism prevailed in lowland populations. 4. This demonstrated the genetically underpinned local adaptation of this insect to harsh mountain environments with a shorter growing season determined by elevation.