ESTUDIOS DE ESPECIES FRATERNAS DE Drosophila DE LAGUNA VERDE, VERACRUZ, MéXICO. III EFECTOS DE LA RADIACIóN SOBRE LA VIABILIDAD

摘要

The sibling species Drosophila melanogaster and D. simulans were collected from two sites at Laguna Verde, Veracruz, México. Isofemale lines were established from each species from both sites. Eggs of each isofemale line were exposed to acute γ-radiation doses of 4.0, 6.0 or 8.0 Gy from an external source, and then placed in vials. Non-irradiated eggs served as a control. Each vial was scored for the number of adults produced. For the flies collected at Site-I, D. melanogaster was superior in viability to D. simulans . However, for the flies collected at Site-II, there was no significant difference in egg to adult survival between the species. A comparison of irradiated and control groups of each species from the various collections showed that in both collections made in July there was a significant reduced viability of irradiated groups, but this difference was completely absent in the collection made in January. A comparison of the control groups of each species from the various collections showed that Site-I D. melanogaster were superior to those from site-II. For D.simulans collected in July, Site-I flies showed significantly greater viability than Site-II flies. However, this difference disappears when one compares collections made at opposite seasons of the year. This complex situation involving both populational and seasonal differences in viability is discussed.