A GENETIC MECHANISM FOR THE EVOLUTION OF SENESCENCE IN CALLOSOBRUCHUS-CHINENSIS (THE AZUKI-BEAN WEEVIL)

Heritabilities and genetic correlations of life-history characters (age-specific fecundities and longevity) in azuki bean weevils were estimated. Heritability estimates were moderate or high for longevity and several age-specific fecundities including early fecundity. A genetic correlation was highly negative between longevity and early fecundity. The negative genetic correlation supports the antagonistic pleiotropy theory for the evolution of senescence. Inbreeding depression for age-specific fecundities was assayed by comparing full-sib mated inbred lines and crosses. There was no tendency for inbreeding depression of fecundities to increase with age. The stability of inbreeding depression at different ages argues against the hypothesis that deleterious mutations accumulated in later ages are one of the causal factors for the evolution of senescence in this insect.