Further experiments on resting site selection by the typical and melanic forms of the moth, Allophyes oxyacanthae (Caradrinidae)

The melanic and typical morphs from 13 families of the moth, Allophyes oxyacanthae (Linnaeus) were tested for evidence of resting site selection in a large box lined with oak bark of three reflectances. For 12 of the families, one or both of the parents originated from two families, 0/1 and 0/3, which had been tested in a similar manner in the previous year. In all of these 12 families typicals showed a preference for the palest background available, "light grey". The melanic results for the same families were significantly heterogeneous but could be partitioned on the basis of parentage, into six families in which melanics preferred light grey, and six families in which melanics preferred the background on which they are most cryptic, dark grey. In the only family in which neither of the parents originated from either 0/1 or 0/3, both typical and melanics showed a preference for the background on which typicals are most cryptic, bare bark. The results of the two years' experiments indicate that it is necessary to postulate that, in addition to the pleiotropic effects of alleles at the melanic locus, another locus (or loci) is involved in the control of resting site selection.