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Communication at the NABS Annual meeting, Keystone, 2000
(194) WHAT DOES POPULATION GENETICS TELL US ABOUT THE SEX LIVES OF MAYFLIES?.
S. Ball. Division of Biological Sciences University of Missouri, Columbia, MO, 65211
Mating systems can have profound effects on the amount and distribution of genetic diversity in populations. I investigated the influence of tychoparthenogenesis on genetic architecture of S. femoratum populations. Tychoparthenogenesis is a form of parthenogenesis in which a small proportion (ca. 5-10%) of unfertilized eggs hatch from typically sexually reproducing females. Populations from temporary streams had the highest hatch success (10%) of unfertilized eggs, followed by permanent streams (5%), and lakes (3.5%). Tychoparthenogenesis was negatively correlated with nymph population density, suggesting that parthenogenesis may provide reproductive assurance. Genetic consequences of tychoparthenogenesis often mimic self-fertilization. Populations with high tychoparthenogenetic capacities should exhibit low genetic diversity and high inbreeding coefficients. As predicted, tychoparthenogenetic capacity was negatively correlated with genetic diversity and positively correlated with inbreeding coefficient. Inbreeding coefficients ranged from .660, to .499, and .441 for temporary stream, permanent stream, and lake populations, respectively, indicating significant levels of inbreeding due to tychoparthenogenesis. There was significant differentiation among subpopulations but no differentiation among populations, indicating substantial gene flow among populations. Adult densities measured over the breeding season also suggested substantial gene flow via adult dispersal. Benefits of tychoparthenogenesis may be limited to certain times of the breeding season when adult densities are low.
Presented at 9:45 AM on Wednesday, May 31, 2000 in Life History Characteristics I
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