CR 62:15-24 (2014)  -  DOI: https://doi.org/10.3354/cr01259

ABSTRACT: The Colorado potato beetle Leptinotarsa decemlineata is an insect pest that can cause a substantial reduction of the potato harvest if left uncontrolled. The aim of this study was to assess the impact of a warmer climate on the Colorado potato beetle in Europe, since temperature influences the beetles’ activity and development from egg to adult, and thereby the potential distribution. The study focuses in particular on the potential northward spread in the Scandinavian countries. In this region, the current climate is not warm enough to sustain the completed development of one generation in all years, and the region does not host a permanent population. Temperature data for 1961-2050 from 4 regional climate models and gridded observed data for 1961-1990 (reference period) were used for model calculations. We simulated the earliest timing of completed development of the first and second generations of the Colorado potato beetle, and assessed the geographical and inter-annual variation in the number of generations per year. The model simulations indicated a shift in the northern limit for establishment of a permanent Colorado potato beetle population by 2020-2050 in comparison with 1961-1990. In particular, the model showed a substantial increase in the frequency of years in which the temperature requirement for development of one generation was fulfilled in the transient zone, i.e. the southern part of Scandinavia. In addition, 2 generations per year may occur more frequently at the current distribution border at 55°N, increasing the risk of northward migration to the Scandinavian countries.

KEY WORDS: Colorado potato beetle · Adaptation · Inter-annual variation · Migration · Regional climate model · Scandinavia · Scenario A1B