Mating competitiveness and the effect of X-rays and aging on males of Tetranychus urticae (Acarina, Tetranychidae) in relation to genetic control

Males of Tetranychus urticae Koch were irradiated with X-ray doses of 4, 8, 24 and 32 krad (which were applied to 0-1 day-old adult virgin males) and tested in mating competition with one-day-old non-irradiated males. A non-significant excess of parental females were mated to the unirradiated males. This consistent trend in favour of females, mated with unirradiated males was highly significant, when the results of all the experiments were bulked. This indicated that radiation impaired the mating competitiveness of males of T. urticae. Aging of irradiated males resulted in a significant decrease of male-mating competitiveness at least within 2 days after irradiation. When 24 krad X-rays irradiated males were tested in mating competition at different ages, with unirradiated males of equal age, it was demonstrated that the reduction in mating competitiveness of aging irradiated males is caused by accelerated aging due to the irradiation treatment