Local adaptation of Brevicoryne brassicae (Homoptera: Aphididae) to host species at Chiapas, Mexico

To assess if the populations of Brevicoryne brassicae that use Brassica campestris and B. oleracea are adaptively differentiated in Balún Canal (Chiapas, Mexico), a reciprocal transfer experiment was carried out. Each population was grown in its native and in the alien environment. Whether an organism established successfully or not on each host was recorded. For each organism, three fitness-related traits were measured: age at first reproduction, number of nymphs produced, and longevity. The aphids, on average, reproduced earlier, produced more nymphs and had lower longevity in the wild species B. campestris than in the cultivated B. oleracea. Analysis of selection indicated that early reproduction and higher longevity are favoured in the cultivated species B. oleracea. Finally, each population had the higher proportion of successful establishment on its native environment (host) than in the alien, supporting a scenario of local adaptation. eng