SELECTION FOR CHARACTER DISPLACEMENT IS CONSTRAINED BY THE GENETIC ARCHITECTURE OF FLORAL TRAITS IN THE IVYLEAF MORNING GLORY

Although interspecific competition for pollination is hypothesized to result in divergence in floral traits (i.e., character displacement), few studies have tested whether selection on these traits differs in the presence and absence of a competitor for pollination. We measured phenotypic selection on floral traits of Lobelia siphilitica L. growing in the presence and absence of Mimulus ringens L., a potential competitor for pollination. Because L. siphilitica is gynodioecious, we estimated selection separately for female and hermaphrodite plants. The presence of M. ringens did not decrease seed set of L. siphilitica. However, the presence of M. ringens did affect selection on daily display size of female L. siphilitica; there was significant selection for smaller daily displays in the absence of M. ringens, but nonsignificant selection for larger displays in the presence of M. ringens. In addition, selection on flower colour did not differ in the presence and absence of M. ringens, but did differ between female and hermaphrodite L. siphilitica. Consequently, our results suggest that the evolution of floral traits in L. siphilitica, but not the evolution of sexual dimorphism in these traits, can be affected by interactions for pollination with M. ringens.

Download Full-text

Selection for developmental time in bean weevil (Acanthoscelides obtectus ): correlated responses for other life history traits and genetic architecture of line differentiation

Entomologia Experimentalis et Applicata ◽

10.1046/j.1570-7458.2003.00007.x ◽

2003 ◽

Vol 106 (1) ◽

pp. 19-35 ◽

Cited By ~ 19

Author(s):

Darka Šešlija ◽

Nikola Tucić

Keyword(s):

Life History ◽

Genetic Architecture ◽

Life History Traits ◽

Developmental Time ◽

Correlated Responses ◽

Bean Weevil ◽

Acanthoscelides Obtectus ◽

Selection For

Download Full-text

Experimental Evidence That Selection Favors Character Displacement in the Ivyleaf Morning Glory

The American Naturalist ◽

10.1086/523948 ◽

2008 ◽

Vol 171 (1) ◽

pp. 1-9 ◽

Cited By ~ 40

Author(s):

Robin Ann Smith ◽

Mark D. Rausher

Keyword(s):

Experimental Evidence ◽

Character Displacement ◽

Morning Glory

Download Full-text

Habitat partitioning during character displacement between the sexes

Biology Letters ◽

10.1098/rsbl.2018.0124 ◽

2018 ◽

Vol 14 (6) ◽

pp. 20180124 ◽

Cited By ~ 2

Author(s):

Stephen P. De Lisle ◽

Samuel Paiva ◽

Locke Rowe

Keyword(s):

Growth Rate ◽

Sexual Dimorphism ◽

Character Displacement ◽

Partial Migration ◽

Habitat Partitioning ◽

Ecological Dynamics ◽

Phenotypic Distribution ◽

Ecological Character Displacement ◽

Selection For ◽

Ecological Differences

Ecological differences between the sexes are often interpreted as evidence of within-species ecological character displacement (ECD), a hypothesis with almost no direct tests. Here, we experimentally test two predictions that are direct corollaries of ECD between the sexes, in a salamander. First, we find support for the prediction that each sex has a growth rate advantage in the aquatic microhabitat where it is most commonly found. Second, we test the prediction that selection for ECD in the breeding environment may affect partial migration out of this environment. We found that phenotype-dependent migration resulted in a shift in the phenotypic distribution across treatments, with the highest sexual dimorphism occurring among residents at high founding density, suggesting that migration and ECD can both be driven by competition. Our work illustrates how complex patterns of habitat partitioning evolve during ECD between the sexes and suggest ECD and partial migration can interact to effect both ecological dynamics and evolution of sexual dimorphism.

Download Full-text

Macroevolutionary consequences of sexual conflict

Biology Letters ◽

10.1098/rsbl.2018.0186 ◽

2018 ◽

Vol 14 (6) ◽

pp. 20180186

Author(s):

Jo S. Hermansen ◽

Jostein Starrfelt ◽

Kjetil L. Voje ◽

Nils C. Stenseth

Keyword(s):

Sexual Selection ◽

Genetic Architecture ◽

Time Frame ◽

Sexual Conflicts ◽

Males And Females ◽

Selection For ◽

Evolutionary Consequences ◽

Future Work ◽

Shared Genetic

Intralocus sexual conflicts arise whenever the fitness optima for a trait expressed in both males and females differ between the sexes and shared genetic architecture constrains the sexes from evolving independently towards their respective optima. Such sexual conflicts are commonplace in nature, yet their long-term evolutionary consequences remain unexplored. Using a Bayesian phylogenetic comparative framework, we studied the macroevolutionary dynamics of intersexual trait integration in stalk-eyed flies (Diopsidae) spanning a time frame of more than 25 Myr. We report that increased intensity of sexual selection on male eyestalks is associated with reduced intersexual eyestalk integration, as well as sex-specific rates of eyestalk evolution. Despite this, lineages where males have been under strong sexual selection for millions of years still exhibit high levels of intersexual trait integration. This low level of decoupling between the sexes may indicate that exaggerated female eyestalks are in fact adaptive—or alternatively, that there are strong constraints on reducing trait integration between the sexes. Future work should seek to clarify the relative roles of constraints and selection in contributing to the varying levels of intersexual trait integration in stalk-eyed flies, and in this way clarify whether sexual conflicts can act as constraints on adaptive evolution even on macroevolutionary time scales.

Download Full-text

Hybrid seed set in wheat is a complex trait but can be improved indirectly by selection for male floral traits

Euphytica ◽

10.1007/s10681-018-2188-1 ◽

2018 ◽

Vol 214 (7) ◽

Cited By ~ 7

Author(s):

Philipp H. G. Boeven ◽

Tobias Würschum ◽

Julia Rudloff ◽

Erhard Ebmeyer ◽

C. Friedrich H. Longin

Keyword(s):

Seed Set ◽

Complex Trait ◽

Hybrid Seed ◽

Floral Traits ◽

Selection For

Download Full-text

The relative strength of selection on modifiers of genetic architecture under migration load

10.1101/2021.12.24.474037 ◽

2021 ◽

Author(s):

Stephen R Proulx ◽

Henrique Teotonio

Keyword(s):

Local Adaptation ◽

Genetic Architecture ◽

Absolute Magnitude ◽

Relative Strength ◽

Demographic Stochasticity ◽

Recombination Rates ◽

Relative Population ◽

Population Sizes ◽

The Mean ◽

Selection For

Gene flow between populations adapting to differing local environmental conditions creates a "migration load" because individuals might disperse to habitats where their survival is low or because they might reproduce with locally maladapted individuals. The amount by which the mean relative population fitness is kept below one creates an opportunity for modifiers of the genetic architecture to spread due to selection. Prior work that separately considered modifiers changing dispersal or recombination rates, or altering dominance or epistasis, has typically focused on the direction of selection rather than its absolute magnitude. We here develop methods to determine the strength of selection on modifiers of the genetic architecture, including modifiers of the dispersal rate, after populations evolved local adaptation. We consider scenarios with up to five loci contributing to local adaptation and derive a matrix model for the deterministic spread of modifiers. We find that selection for modifiers of epistasis and dominance is stronger than selection for decreased recombination, and that selection for partial reductions in recombination are extremely weak, regardless of the number of loci contributing to local adaptation. The spread of modifiers for a reduction in dispersal depends on the number of loci, pre-existing epistasis and extent of migration load. We identify a novel effect, that modifiers of dominance are more strongly selected when they are unlinked to the locus that they modify. Overall, these results help explain population differentiation and reproductive isolation and provide a benchmark to compare selection on genetic architecture modifiers in finite population sizes and under demographic stochasticity.

Download Full-text

Gene buddies: linked balanced polymorphisms reinforce each other even in the absence of epistasis

PeerJ ◽

10.7717/peerj.5110 ◽

2018 ◽

Vol 6 ◽

pp. e5110 ◽

Cited By ~ 2

Author(s):

Jacob A. Tennessen

Keyword(s):

Genetic Architecture ◽

Evolutionary Dynamics ◽

Balancing Selection ◽

Natural Populations ◽

Adaptive Variation ◽

Recombination Rates ◽

Future Studies ◽

Close Physical Proximity ◽

Selection For ◽

Independent Effects

The fates of genetic polymorphisms maintained by balancing selection depend on evolutionary dynamics at linked sites. While coevolution across linked, epigenetically-interacting loci has been extensively explored, such supergenes may be relatively rare. However, genes harboring adaptive variation can occur in close physical proximity while generating independent effects on fitness. Here, I present a model in which two linked loci without epistasis are both under balancing selection for unrelated reasons. Using forward-time simulations, I show that recombination rate strongly influences the retention of adaptive polymorphism, especially for intermediate selection coefficients. A locus is more likely to retain adaptive variation if it is closely linked to another locus under balancing selection, even if the two loci have no interaction. Thus, two linked polymorphisms can both be retained indefinitely even when they would both be lost to drift if unlinked. While these results may be intuitive, they have important implications for genetic architecture: clusters of mutually reinforcing genes may underlie phenotypic variation in natural populations, and such genes cannot be assumed to be functionally associated. Future studies that measure selection coefficients and recombination rates among closely linked genes will be fruitful for characterizing the extent of this phenomenon.

Download Full-text