in tristylous Eichhornia paniculata (Pontederiaceae).
The observed nonrandom visit orders would result in disassortative mating between corolla color phenotypes of nonmodel deceptively pollinated species.
In conclusion, these laboratory studies show that the initial sampling behavior of pollinators visiting deceptive species that do not mimic any other rewarding species could induce negative FDS and disassortative mating on corolla color phenotypes within a plant population.
In tristylous populations, frequencies of the three mating types, or "style morphs," are driven towards a single stable equilibrium by frequency-dependent selection owing to disassortative mating among morphs (Heuch 1979a,b; Heuch and Lie 1985; Barrett et al.
Ploidy, however, does not affect the theoretical dynamics of tristylous populations because, with only two alleles per locus and strong disassortative mating among morphs, autotetraploid tristyly loci effectively behave as diploid loci (Heuch and Lie 1985; Eckert and Barrett 1992).
Fisher (1941, 1944) first suggested that disassortative mating among style morphs in tristylous plant populations should lead to a single equilibrium with the three morphs at equal frequencies.
In populations with low frequencies of the M morph, disassortative mating among morphs gives it a siring advantage, thereby increasing its frequency in the progeny generation.
Both the reciprocal arrangement of anthers and stigma and the incompatibility system should promote disassortative mating
(mating among different morphs).
If females were choosing males to increase their offspring viability, then disassortative mating
with respect to karyotype would be observed.
Theoretical models indicate that all three morphs should occur at equal frequency within populations, because they are maintained by frequency-dependent selection due to strong disassortative mating
among the morphs (Charlesworth, 1979; Heuch, 1979; Barrett et al.