Genetics of Red Body Colour in Armadillidium vulgare

Abstract

PREVIOUS work1,2 and also many unpublished results have shown that in the woodlouse Armadillidium vulgare Latr. red body colour and a colour pattern called type D behave as simple autosomal dominants to the common black and grey types (the only complication being that in adult animals type D is sex-limited to the female sex). Collinge3,4,5, however, has reported results which do not agree with mine in that he fails to find any segregations. I was inclined to believe that Collinge's results were due to his scoring animals before they were really old enough for the different colour types to be distinguished ; for he had stated6 that, when he examined some young from the variety rufobrunneus (red) at just over three weeks old, no trace of red or brown coloration was apparent, and that, if he had not known their history, he would have identified them as young specimens of the variety plumbeus (grey black). While it must be emphasized that in the majority of cases red colour does behave as a simple dominant, and that one does usually obtain good 1 : 1 and 3 : 1 segregations, I have recently obtained some results which confirm Collinge's observations.