Abstract
Three albino females were discovered in a field population of Panonychus osmanthi, the albinism being a result of spontaneous mutation. To determine the genetic control of the albinism, standard genetic crosses were conducted. Apparently the albinism was recessive to the normal pigmented trait and was under monogenic control. albino mites with reddish eye-spots were obtained when pigmented hybrid females obtained from crosses between the albino and normal strains were either kept virgin or mated to males with various phenotypes. The eye-spots of albino females were not passed onto the next generation irrespective of the male phenotype. These results suggested that some pigment precursor possessed by pigmented females is responsible for the appearance of the eye-spots. Hybrid females resulted in a reduction in hatchability in F2 eggs and a distortion of the female: male ratio. These phenomena might be explained in terms of the difference in mortality between haploid and diploid eggs: i.e., crosses between hybrid females and pure albino males without eye-spots resulted in the death of about 50% of both haploid and diploid eggs, whereas crosses between hybrid females and either normal males or eye-spotted albino males resulted in the death of about 50% of haploid eggs but did not cause the death of diploid eggs.
