The genetic properties of egg laying of virgin females of Tribolium castaneum

Abstract

SUMMARYInbreeding was established by brother-sister matings and it was carried out for seven generations in the Consejo population of Tribolium casianeum. From 105 inbred lines at the start, 53 lines reached the end of the experiment. Losses of lines were independent of the level of inbreeding.The trait studied was 4-day egg laying of virgin females. It has been shown that this trait did not present either inbreeding depression or hybrid vigour. The phenotypic variance and its between-and within-line components also behaved as expected under the additive model as inbreeding progressed. Estimation of genetic parameters in the base population confirmed that egg laying of virgin females is an essentially additive trait.Other traits-2-day egg laying of fecundated females, precocity and percentage viability-showed a smaller heritability than egg laying of virgin females and considerable inbreeding depression. No connection was found between virgin female egg laying and percentage viability.The suggestion is made that egg laying of virgin females in the Consejo population can be considered a peripheral trait with respect to fitness.,

Changes in the distribution of the genetic variance of a quantitative trait in small populations of Drosophila melanogaster

“…Its mean will decrease with time as (1 -FJ V A , while its variance will increase and rapidly approach an asymptotic value, largely because of linkage disequilibrium built up by sampling (Bulmer, 1976;Avery and Hill, 1977). Similarly, when 2 additive traits are considered, the expected value of the within-line genetic covariance will decrease as (1 -FJ cov A , cov A being the genetic covariance in the base population, and its variance will increase also towards an asymptotic value, due to disequilibrium (Avery and Hill, 1977 (Rasmuson, 1952;Kidwell and Kidwell, 1966); egg-laying of virgin females in Iribolium castaneum (Lopez-Fanjul and Jodar, 1977); and litter size in mice (Bowman and Falconer, 1960). In these experiments, the within-line phenotypic variance oscillated more or less widely without showing a definite trend and only appeared to decline for the 2 bristle systems analysed by Rasmuson (1952).…”

Tribolium beetles as a model system in evolution and ecology

“…In addition to studying adaptation, Tribolium experiments have been used to understand the causes and consequences of stochastic processes such as mutation and drift in evolution (e.g., Rich et al 1979 ). Inbreeding depression has been studied in detail in Tribolium , and inbreeding has been shown to have negative effects on a range of traits, including productivity and viability (López-Fanjul and Jódar 1977 ). Susceptibility to inbreeding depression can vary between populations and affect suites of traits within populations (Pray and Goodnight 1995 ; Pray 1997 ).…”

Developmental trajectories and breakdown in F1 interpopulation hybrids of Tribolium castaneum

“…Columbia Georgia India Tribolium beetles have the ability to lay unfertilized eggs when not inseminated, although the rate of egg lay is very low (Lopez-Fanjul and Jodar 1977). These eggs do not hatch and desiccate within the first few days after laying.…”