Genetic models of female-biased sex ratios in subdivided populations include individual selection (inbreeding and sib mating, dispersal, and local mate competition (LMC) that assumes restricted mating among the progeny of a few females) and group selection. I examined two genetic assumptions of these models in a parasitic wasp, Muscidifurax raptor (Hymenoptera: Pteromalidae), a solitary ectoparasitoid of dipteran pupae. These assumptions are (1) sex ratio genotypes produce similar phenotypes over a range of environmental conditions (no genotype-environment interactions), and (2) sex ratio is genetically uncorrelated with other life history traits. / I found variation among five strains in sex ratio and daily fecundity, but there were no strain-environment interactions. The strains all increased the proportion of males with increasing density of ovipositing females. M. raptor is not a pure LMC species. Males emerge before females and await them for mating, but emergence spans 8 days and males are winged and capable of dispersal. Alternative models for sex ratio variation in M. raptor include differential dispersal by males and females and group selection models. / In a diallel analysis of three strains, I found that the genetic variance in sex ratio and other life history traits includes directional dominance, indicating that inbreeding will reduce the bias in sex ratio. I also found dominance genetic correlations and maternal effects correlations among sex ratio, daily fecundity, and development time. Females that develop quickly have higher fecundity and produce more female-biased sex ratios. The correlation is a result of the sequence of sex allocation during an oviposition bout: male eggs are oviposited early whereas females are oviposited later. / Sex ratio in M. raptor is a composite trait that reflects variation in fecundity as well as the propensity to fertilize eggs. The genetic correlations between sex ratio and other life history characteristics indicate that sex ratio may not evolve freely, but is constrained by selection on other traits. / Source: Dissertation Abstracts International, Volume: 51-11, Section: B, page: 5125. / Major Professors: Joseph Travis; Daniel Simberloff. / Thesis (Ph.D.)--The Florida State University, 1990.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78331 |
| Contributors | Antolin, Michael Franc., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 230 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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