Monitoring of adult emergence in the pine processionary moth between 1970 and 1984 in Mont Ventoux, France

Abstract

The current climate change has marked impacts on the phenology of species, i.e., the timing of the various stages of their life cycle. Yet, to fully understand how phenological patterns are modified by the changes of temperature regimes, it is of prime importance to rely on high quality historical data. We here document a very valuable data set including the individual monitoring of the end of the larval phase and the date of adult emergence in the pine processionary moth Thaumetopoea pityocampa. A total of 46 479 caterpillars were followed between 1970 and 1984 in 6 sites along an altitudinal gradient in southern France. As optional prolonged diapause occurs in this species, i.e. some individuals experience one or more years of diapause before emerging, the caterpillars sampled any given year were monitored during up to 5 years. The goal was to give precise information about phenology in this species to further analyse its spatial and temporal patterns of variation.This dataset is unique by its richness and the type of data it contains. Phenology in the pine processionary moth is often monitored by the use of pheromone traps in the field, which does not provide all the necessary information because it is then not possible to trace back the exact origin of the moth trapped, nor to characterise other steps of the life cycle. More, as it corresponds to historical data dating back to the 70s and the 80s, it provides a historical baseline of trends in the pre-warming period.