Correlated response of autogeny to selection for adult starvation resistance in the blowfly, Lucilia cuprina.
We withheld sucrose from adults in three lineages of Lucilia cuprina, producing a four-fold greater mortality than in control lineages, in order to impose direct selection for carbohydrate starvation resistance. The frequency of autogeny (maturation of eggs in the absence of adult protein feeding) increased as a correlated response by an average of 4.9 to 9.2% per generation in three lineages subjected to starvation over five generations. The frequency of autogeny fluctuated but did not display a significant net change in three control lineages. Autogeny in L. cuprina seems to behave as a threshold trait, with a continuous, genetically-based underlying disposition producing discrete phenotypes. The heritability of autogeny in our laboratory lineages was estimated to be 0.09 to 0.39, 0.04 to 0.36, and -0.08 to 0.30 (95% confidence intervals). Despite the potential for autogeny to evolve and despite protein limitation of female fecundity in Australian populations of L. cuprina, the trait is rare or absent in the field. Genetic variation for autogeny may be maintained, but at sub-threshold levels, by nutrient availability in the field, while trade-offs associated with autogeny probably limit the net fitness benefit of the trait and prevent the evolution of a noticeable frequency of autogenous females.
Cooper
K
K
Department of Biological Sciences, Monash University, P.O. Box 18, Melbourne, Victoria 3800, Australia.
Burd
M
M
Lefevere
K S
KS
D000818:Animals; D004175:Diptera / Q000235:genetics* / Q000254:growth & development; D005260:Female; D008297:Male; D010063:Ovum / Q000502:physiology; D012641:Selection, Genetic; D013217:Starvation