Newly evolved cytoraces of nasuta–albomicans complex of drosophila live better than their parents as revealed by life-history trait analysis at three different temperatures

The long-range interracial hybridization experiments between a pair of cross fertile races, Drosophila nasuta nasuta (2n = 8) and Drosophila nasuta albomicans (2n = 6) have resulted in the evolution of two new karyotypic strains called cytoraces 1 and 2, which harbour chromosomes from both their parents and differ in their karyotypic composition, mating preference and morphometric traits. In the present study, the effect of temperature on certain life-history traits such as lifetime fecundity, lifetime fertility, ovariole number and longevity of virgin and mated males and females was tested in the parents and two cytoraces. The results revealed that in most of the assessments, the newly evolved cytoraces showed maximum fitness, suggesting that the newly evolved cytoraces survive and live better than their parental races