Post-introduction evolution in the biological control agent Longitarsus jacobaeae (Coleoptera: Chrysomelidae).
Rapid evolution has rarely been assessed in biological control systems despite the similarity with biological invasions, which are widely used as model systems. We assessed post-introduction climatic adaptation in a population of Longitarsus jacobaeae, a biological control agent of Jacobaea vulgaris, which originated from a low-elevation site in Italy and was introduced in the USA to a high-elevation site (Mt. Hood, Oregon) in the early 1980s. Life-history characteristics of beetle populations from Mt. Hood, from two low-elevation sites in Oregon (Italian origin) and from a high-elevation site from Switzerland were compared in common gardens. The performance of low- and high-elevation populations at a low- and a high-elevation site was evaluated using reciprocal transplants. The results revealed significant changes in aestival diapause and shifts in phenology in the Mt. Hood population, compared with the low-elevation populations. We found increased performance of the Mt. Hood population in its home environment compared with the low-elevation populations that it originated from. The results indicate that the beetles at Mt. Hood have adapted to the cooler conditions by life-history changes that conform to predictions based on theory and the phenology of the cold-adapted Swiss beetles.
Department of Plant, Soil, and Entomological Sciences, University of Idaho Moscow, ID, USA ; Department of Bioagricultural Sciences and Pest Management, Colorado State University Fort Collins, CO, USA.
Marianna
M
Szűcs
Urs
U
Schaffner
William J
WJ
Price
Mark
M
Schwarzländer
aestivation; biological control agent; body size; climatic adaptation; contemporary evolution; larval development