ROBINSON, A. S. 1973. Increase in fertility, with repeated mating, of gamma irradiated male codling moths, Laspeyresia pomonella (L.) (Lepidoptera: Olethreutidae). Can. J. Zool. 51 : 427-430. Irradiated male codling moths. Laspeyresia pomonella (L.), mated fewer times and induced a poorer ovipositional response in mated females than did nonirradiated males. The fertility of the nonirradiated males was not affected by repeated mating but there was a significant increase in the fertility of consecutive matings of the irradiated males. The transfer of a spermatophore by either type of male did not always result in oviposition, but this malfunction of the male occurred sign~ficantly more times in the irradiated series. ROBINSON, A. S. 1973. Increase in fertility, with repeated mating, of gamma irradiated male codling moths, Laspeyresiapomonella (L.) (Lepidoptera: Olethreutidae). Can. J. Zool. 51: 427-430.Des mlles de la pyrale de la pornme, hpeyresiapomonella (L.), ayant subi me irradiation s ' y u p l e n t m o m souvent que les males non-irradiks et cet accouplernent provoquc chez Iw fernella ~m p l r q u b un comportement de ponte moins rkussi. Chez les males non-irradib, f'accouplement frequent nqalTecte pas la fertilite, mais on observe une augmentation significative de la fertilitt chez les m i l a i m d i k , apds 6es accouplements rkpktks. La transmission du spermalophon: par I'un ou l'autre type de mCle n'induit pas toujours la ponte, mais la frbuence de cette deficience wt sign~ficativcrnent plus grande chez les mlles irradib. rhaduit par Ic journal]

SUMMARYIn the onion fly, Delia antiqua. a fertile, Y-linked translocation involving chromosomes Y and 2 was irradiated with fast neutrons to induce new complexes involving the Y-chromosome. This chromosome is male determining in the onion fly. Such complexes can be used for the development of genetic sexing systems and also for the introduction of sterility into field populations following release.Irradiation reduced egg fertility by 54 per cent and significantly reduced larval survival but it had no effect on the F1 sex ratio. By measuring the fertility of 807 F1 males following outcrossing, 112 semi-sterile progenies were isolated of which 11 were lost, 29 showed no inheritance of the semi-sterility, 59 were new autosomal translocations and 13 were new complex Y-linked translocations. This classification was accomplished by checking the fertilities of outcrossed F2 males and females. Following cytological observation it was revealed that one of these new complexes involved four chromosome pairs, the remainder involved three. There appeared to be no correlation between the fertility of the translocation and the complexity of the rearrangement. The utilization of these rearrangements in the development of the genetic sexing technique for the onion fly is discussed, together with an assessment of their use for fertility reduction in natural populations.