Data from: A common-garden experiment to quantify evolutionary processes in copepods: the case of emamectin benzoate resistance in the parasitic sea louse Lepeophtheirus salmonis

Background:The development of pesticide resistance represents a global
challenge to food production. Specifically for the Atlantic salmon
aquaculture industry, parasitic sea lice and their developing resistance
to delousing chemicals is challenging production. In this study, seventeen
full sibling families, established from three strains of Lepeophtheirus
salmonis displaying differing backgrounds in emamectin benzoate (EB)
tolerance were produced and quantitatively compared under a common-garden
experimental design. Lice surviving to the preadult stage were then
exposed to EB and finally identified through the application of DNA
parentage testing. Results: With the exception of two families (19 and
29%), survival from the infectious copepod to preadult stage was very
similar among families (40-50%). In contrast, very large differences in
survival following EB exposure were observed among the families (7.9-74%).
Family survival post EB exposure was consistent with the EB tolerance
characteristics of the strains from which they were established and no
negative effect on infection success were detected in association with
increased EB tolerance. Two of the lice families that displayed reduced
sensitivity to EB were established from a commercial farm that had
previously used this chemical. This demonstrates that resistant alleles
were present on this farm even though the farm had not reported treatment
failure. Conclusions: To our knowledge, this represents the first study
where families of any multi-cellular parasite have been established and
compared in performance under communal rearing conditions in a
common-garden experiment. The system performed in a predictable manner and
permitted, for the first time, elucidation of quantitative traits among
sea lice families. While this experiment concentrated on, and provided a
unique insight into EB sensitivity among lice families, the experimental
design represents a novel methodology to experimentally address both
resistance development and other evolutionary questions in parasitic
copepods.