Search results for "disruptive selection"
showing 3 items of 3 documents
Territoriality versus flocking in the Zenaida dove (Zenaida aurita): resource polymorphism revisited using morphological and genetic analyses.
2011
11 pages; International audience; The term “resource polymorphism” refers to the existence of alternative phenotypes in relation to resource use, as a result of disruptive selection. Evidence for resource polymorphism is widespread in fish but remains scarce in birds. Although Zenaida Doves (Zenaida aurita) usually defend year-round territories, doves on Barbados can also be observed foraging at seed-storage sites in large flocks with little, if any, inter-individual aggression. On the basis of morphological variation, it has been suggested (Sol et al. 2005) that this represents a case of resource polymorphism, primarily driven by competition for territories. Using new data, we revisited th…
Genetic variability at neutral markers, quantitative trait loci and trait in a subdivided population under selection
2003
Abstract Genetic variability in a subdivided population under stabilizing and diversifying selection was investigated at three levels: neutral markers, QTL coding for a trait, and the trait itself. A quantitative model with additive effects was used to link genotypes to phenotypes. No physical linkage was introduced. Using an analytical approach, we compared the diversity within deme (HS) and the differentiation (FST) at the QTL with the genetic variance within deme (VW) and the differentiation (QST) for the trait. The difference between FST and QST was shown to depend on the relative amounts of covariance between QTL within and between demes. Simulations were used to study the effect of se…
Geranium sylvaticum increases pollination probability by sexually dimorphic flowers
2022
Sexual dimorphism is expressed as different morphologies between the sexes of a species. Dimorphism is pronounced in gynodioecious populations which consist of female and hermaphrodite individuals. The small size of female flowers in gynodioecious species is often explained by resource re-allocation to seed production instead of large flowers. However, pollinator attraction is critical to female fitness, and factors other than resource savings are needed to explain the small size of female flowers. We hypothesized that the floral size dimorphism in the perennial gynodioecious Geranium sylvaticum (L.) is adaptive in terms of pollination. To test this “pollination hypothesis,” we video record…