Aiming to unravel genetic mechanisms underlying the polyphagous two-spotted spider mite ’s unique host adaptation ability, an experimental ‘pseudo-panmictic’ population was created to: (i) Uncover eQTLs (mainly trans) linked to a host shift, relying on predominantly RNA-seq (ii) Examine genotype-environment interactions in different hosts (iii) Study genetic selection for/against relevant genotypes identified in (i) and (ii) caused by a new host