Spatial movements and changes of cockchafer-strains (Melolontha melolontha L.) which have a three year life-cycle were reconstructed in Switzerland since the 13th century by dendrochronological methods. Using the coefficient of parallel variation or the Gleichläufigkeit, we tested 1319 historical tree-ring series of oak (Quercus sp.) with artificial time series simulating a decrease of growth every third year. All statistically significant tree-ring series were mapped separately for the three possible cyclic outbreaks of cockchafer. It is clearly shown that one strain has dominated in Switzerland for the last 800 years. The geographical distribution of cockchafer-strains seems to be stable for certain areas over many centuries. Our proposed method might be also helpful for detecting imported timber of historical settlements.