ABSTRACT.1Mandible tip length has been used to estimate the age of individualC.problematicusHerbst caught over an altitude range of more than 700 m in northern England.2At 100 m the great majority of females laid eggs in the summer of their emergence as adults. The female life‐cycle is predominantly annual and 24% only of the egg‐bearing individuals were in their second year.3Above 250 m, most females did not reproduce until the summer of the year following emergence, giving a biennial life‐cycle. 96% of egg‐bearing females caught above 830 m were in their second year.4All the males caught during the breeding season at 100 m had emerged within that calendar year and it is concluded that the male life‐cycle is annual at this altitude.5Above 250 m, 83% of the males caught during the breeding season were in their first calendar year, suggesting that recently emerged males may inseminate second year females and also that the male life‐cycle is predominantly annual over the whole altitude range studied.6At the higher temperatures of the lowland site females not only produce eggs in the year of emergence, they also produce more eggs per individual than at the higher sites. Egg production depends on food intake which involves mandible wear and individuals at the lowland site have significantly higher rate of mandible wear than at the sites