“…For instance, the circadian clock gene timeless was found to be in control of diapause incidence (Sandrelli et al, ) and allele frequencies of timeless alleles differentially affecting diapause induction behaviour were shown to covary over latitude (Tauber et al, ) in Drosophila . This pattern, a functional role of one or several circadian clock genes in the control of diapause induction and associated cline in allele frequencies for these genes in natural populations is recurrently observed, e.g., for the parasitic wasp Nasonia vitripennis ( period, cycle and cryptochrome ; Paolucci, Salis, Vermeulen, Beukeboom, & Zande, ) or more recently for the speckled wood butterfly ( period & timeless ; Pruisscher, Nylin, Gotthard, & Wheat, ). However, Emerson, Dake, Bradshaw, and Holzapfel () found that the photoperiodic seasonal clock in control of diapause can evolve independently from the circadian clock.…”