Sexual dimorphism in floral traits of gynodioecious Lobelia siphilitica (Lobeliaceae) is consistent across populations

Botany ◽  
2012 ◽  
Vol 90 (12) ◽  
pp. 1245-1251 ◽  
Author(s):  
Christina M. Caruso
Keyword(s):  
Sexual Dimorphism ◽  
Genetic Correlations ◽  
Species Range ◽  
Flower Size ◽  
Floral Traits ◽  
Flower Number ◽  
Gender Dimorphism

In angiosperms, the evolution of gender dimorphism is often correlated with the evolution of sexual dimorphism in floral traits. The magnitude of sexual dimorphism will reflect both sex-specific selection and constraints on evolution in response to this selection. If the evolution of sexual dimorphism is constrained by genetic correlations, then trait means are predicted to evolve more quickly than the magnitude of sexual dimorphism in the same traits. To test whether mean floral traits evolve more quickly than sexual dimorphism in these traits, I measured flower size and flower number of gynodioecious Lobelia siphilitica L. from 10–14 populations across the species’ range. Females produced more flowers than hermaphrodites, but neither mean flower number nor the magnitude of dimorphism in flower number varied among populations. Pistillate flowers were smaller than perfect flowers, and mean flower size varied among populations. However, the magnitude of dimorphism in flower size did not vary. My results suggest that the evolution of sexual dimorphism in flower size, but not necessarily flower number, could be constrained by within- or between-sex genetic correlations in L. siphilitica.

scholarly journals Temporal dynamics of sexual dimorphism in a dioecious species

2020 ◽  
Vol 126 (3) ◽  
pp. 471-480
Author(s):  
L Moquet ◽  
L Lateur ◽  
A-L Jacquemart ◽  
I De Cauwer ◽  
M Dufay
Keyword(s):  
Sexual Dimorphism ◽  
Plant Species ◽  
Temporal Dynamics ◽  
Flower Size ◽  
Flowering Plant ◽  
Floral Traits ◽  
Flower Number ◽  
Pollinator Behaviour ◽  
Flower Production ◽  
Flowering Season

Abstract Background and Aims Sexual dimorphism for floral traits is common in dioecious plant species. Beyond its significance for understanding how selection acts on plant traits through male vs. female reproductive function, sexual dimorphism has also been proposed as a possible risky characteristic for insect-pollinated plants, as it could drive pollinators to forage mostly on male plants. However, even though most flowering plant species spread their flowering across several weeks or months, the temporal variation of floral phenotypes and sexual dimorphism have rarely been investigated. Methods We performed a survey of male and female plants from the dioecious generalist-pollinated Silene dioica (Caryophyllaceae) in a common garden experiment, over two consecutive flowering seasons. Flower number and floral size were measured each week, as well as pollen quantity and viability in male plants. Key Results Sexual dimorphism was found for all investigated floral traits, with males showing an overall higher investment in flower production and flower size. Males and females showed a similar temporal decline in flower size. The temporal dynamics of daily flower number differed between sexes, with males showing a peak in the middle of their flowering season, whereas flower production by females was quite stable over time. At the scale of the experimental population, both individual and floral sex ratios appeared to vary across the flowering season. Moreover, because the onset of flowering varied among plants, the magnitude of sexual dimorphism in floral size also fluctuated strongly through time. Conclusions Capturing male/female differences with only one temporal measurement per population may not be informative. This opens stimulating questions about how pollinator behaviour and resulting pollination efficiency may vary across the flowering season.

scholarly journals Effects of sexual dimorphism on pollinator behaviour in a dioecious species

2021 ◽  
Author(s):  
Laura Moquet ◽  
Anne-Laure Jacquemart ◽  
Mathilde Dufay ◽  
Isabelle De Cauwer
Keyword(s):  
Sexual Dimorphism ◽  
Bombus Terrestris ◽  
Male Flower ◽  
Pollen Grains ◽  
Flower Size ◽  
Pollination Efficiency ◽  
Flower Number ◽  
Pollinator Behaviour ◽  
Number Of Visits ◽  
Female Flowers

Floral traits often display sexual dimorphism in insect-pollinated dioecious plant species, with male individuals typically being showier than females. While this strategy is theorized to be optimal when pollinators are abundant, it might represent a risk when they become scarce, because the disproportionately high number of visits on the most attractive sex, males, might preclude efficient pollen transfer from males to females. Here, the effect of sexual dimorphism on pollination efficiency was assessed in experimental arrays of dioecious Silene dioica that were exposed to one frequent visitor of the species, Bombus terrestris, and that differed in the magnitude of sexual dimorphism for either flower number or flower size. While flower size dimorphism did not impact pollination efficiency, we found that flower number dimorphism negatively affected the number of visits on female plants, on female flowers and on the number of female flowers visited after a male flower. However, flower number dimorphism had no effect on the number of pollen grains deposited per stigma, presumably because the decrease in the number of visits to female flowers was compensated by a higher number of pollen grains deposited per visit.

scholarly journals Geographic variation in floral traits is associated with environmental and genetic differences among populations of the mixed mating species Collinsia heterophylla (Plantaginaceae)

Botany ◽  
2017 ◽  
Vol 95 (2) ◽  
pp. 121-138 ◽  
Author(s):  
Åsa Lankinen ◽  
Josefin A. Madjidian ◽  
Stefan Andersson
Keyword(s):  
Environmental Factors ◽  
Mating System ◽  
Climatic Factors ◽  
Environmental Influence ◽  
Genetic Correlations ◽  
Flower Size ◽  
Floral Traits ◽  
Mixed Mating ◽  
Floral Trait ◽  
Stigma Receptivity

Relatively few studies have investigated how geography, environmental factors, and genetics affect floral trait variation. We used mixed-mating Collinsia heterophylla Buist to explore variation in a suite of floral traits related to mating system in populations representing four geographic regions of California, USA, and relate this variation to geography, climatic factors, and local site characteristics. We evaluated the environmental vs. genetic trait variability in the greenhouse. Stage of anther–stigma contact correlated positively with temperature, stage of stigma receptivity was negatively associated with vegetation cover, and flower size differed among populations without any clear relation to environmental factors. Greenhouse data indicated heritability for stage of anther–stigma contact, flower size, and time to flowering, and positive correlations between field and greenhouse for stage of stigma receptivity and flower size; however, stage of anther–stigma contact showed a high degree of environmental influence. Stage of anther–stigma contact covaried positively with stage of stigma receptivity and flower size across maternal families, indicating genetic correlations between traits. In conclusion, phenotypic floral variation within mixed-mating C. heterophylla is mostly determined by a genetic component. Geography, environment, and genetics affect traits differently, suggesting that ecological and evolutionary processes contribute to shaping variability in mating system-related traits.

scholarly journals Polyploidization and sexual dimorphism of floral traits in a subdioecious population of Dasiphora glabra

2020 ◽  
Author(s):  
Lin-Lin Wang ◽  
Na-Cai Yang ◽  
Min-Yu Chen ◽  
Yong-Ping Yang ◽  
Yuan-Wen Duan
Keyword(s):  
Sexual Dimorphism ◽  
Genome Size ◽  
Seed Production ◽  
Flower Size ◽  
Floral Traits ◽  
Pollen Transfer ◽  
Pollinator Visitation ◽  
Dioecious Plants ◽  
Male And Female ◽  
Male Flowers

Abstract Aims Sexual dimorphism is a common trait in plants with sex separation, which could influence female and male functions differently. In a subdioecious population of Dasiphora glabra on the Qinghai-Tibet Plateau, we investigated sexual dimorphism of floral traits and their effects on pollinator visitation, pollen flow and seed production. We also examined differences in genome size of hermaphroditic and dioecious plants. Methods We examined sexual dimorphism in flower number, flower size, and pollen and ovule production in a subdioecious population of D. glabra. We compared pollinator visitation, pollen dispersal, and seed production between sexes. We also examined the genome size of three sex morphs using flow cytometry. Important findings The number of hermaphroditic plants was significantly more than that of male and female plants, and dioecious plants accounted for ca. 40% in the study population. Hermaphroditic plants produced significantly more flowers than male and female plants. Flower size of male flowers was significantly larger than that of female and hermaphroditic flowers. Male flowers did not produce more pollen grains than hermaphroditic flowers, but female flowers produced more ovules than hermaphroditic flowers. Flies were the most frequent flower visitors and preferred large flowers, but their movements between flowers did not show any preference to large flowers. Simulated pollen flows suggested that effective pollen transfer was generally low for both hermaphroditic and male flowers, corresponding to the low seed set of naturally pollinated flowers. DNA contents of male and female plants were ca. four times than those of hermaphroditic plants. These results suggest male and female individuals have undergone polyploidy events and thus are not compatible with hermaphroditic individuals. Sexual dimorphism in floral traits in relation to pollination of dioicous plants might show an advantage in female and male functions, but this advantage is masked largely by low effectiveness of pollen transfer.

Quantitative Genetics of Drosophila Melanogaster. II. Heritabilities and Genetic Correlations between Sexes for Head and Thorax Traits.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 421-433
Author(s):  
D E Cowley ◽  
W R Atchley
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Dimorphism ◽  
Genetic Analysis ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Imaginal Disc ◽  
Genetic Correlations ◽  
Body Parts ◽  
Quantitative Genetic ◽  
Males And Females

Abstract A quantitative genetic analysis is reported for traits on the head and thorax of adult fruit flies, Drosophila melanogaster. Females are larger than males, and the magnitude of sexual dimorphism is similar for traits derived from the same imaginal disc, but the level of sexual dimorphism varies widely across discs. The greatest difference between males and females occurs for the dimensions of the sclerotized mouthparts of the proboscis. Most of the traits studied are highly heritable with heritabilities ranging from 0.26 to 0.84 for males and 0.27 to 0.81 for females. In general, heritabilities are slightly higher for males, possibly reflecting the effect of dosage compensation on X-linked variance. The X chromosome contributes substantially to variance for many of these traits, and including results reported elsewhere, the variance for over two-thirds of the traits studied includes X-linked variance. The genetic correlations between sexes for the same trait are generally high and close to unity. Coupled with the small differences in the traits between sexes for heritabilities and phenotypic variances, these results suggest that selection would be very slow to change the level of sexual dimorphism in size of various body parts.

scholarly journals Lisianthus Growth and Flowering Responses to Uniconazole

HortScience ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 150-152 ◽  
Author(s):  
Terri Woods Starman
Keyword(s):  
Plant Height ◽  
Foliar Spray ◽  
Flower Size ◽  
Flower Number ◽  
Eustoma Grandiflorum ◽  
Height Control ◽  
Foliar Sprays ◽  
Potted Plant ◽  
Butanedioic Acid ◽  
Time Of Harvest

One and two foliar spray and single-drench applications of uniconazole were applied to Eustoma grandiflorum (Raf.) Shinn (lisianthus) `Yodel Blue' to determine optimal concentrations for potted plant height control. A single uniconazole spray at 10.0 mg·liter-1 applied 2 weeks after pinching, two uniconazole applications at 5.0 mg·liter -1 applied 2 and 3 weeks after pinching, or a drench at 1.60 mg a.i. per pot applied 2 weeks after pinching gave equally good height control. At these concentrations, uniconazole was similar in its effect on plant height to daminozide foliar sprays at 7500 and 2500 mg·liter-l applied once and twice, respectively. Drenching with uniconazole at 1.60 mg a.i. per pot did not increase days to flower (DTF), whereas foliar spray applications did. Drenching did not reduce flower size, but increased flower number at time of harvest. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide);(E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-01 (uniconazole).

QUANTITATIVE GENETICS OF DROSOPHILA MELANOGASTER. I. SEXUAL DIMORPHISM IN GENETIC PARAMETERS FOR WING TRAITS

Genetics ◽  
1986 ◽  
Vol 114 (2) ◽  
pp. 549-566
Author(s):  
David E Cowley ◽  
William R Atchley ◽  
J J Rutledge
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Dimorphism ◽  
Dosage Compensation ◽  
Genetic Parameters ◽  
Genetic Model ◽  
Genetic Correlations ◽  
Error Variance ◽  
Minor Effect ◽  
Phenotypic Variance ◽  
Environmental Variance

ABSTRACT Sexual dimorphism in genetic parameters is examined for wing dimensions of Drosophila melanogaster. Data are fit to a quantitative genetic model where phenotypic variance is a linear function of additive genetic autosomal variance (common to both sexes), additive genetic X-linked variances distinct for each sex, variance due to common rearing environment of families, residual environmental variance, random error variance due to replication, and variance due to measurement error and developmental asymmetry (left vs. right sides). Polygenic dosage compensation and its effect on genetic variances and covariances between sexes is discussed. Variance estimates for wing length and other wing dimensions highly correlated with length support the hypothesis that the Drosophila system of dosage compensation will cause male X-linked genetic variance to be substantially larger than female X-linked variance. Results for various wing dimensions differ, suggesting that the level of dosage compensation may differ for different traits. Genetic correlations between sexes for the same trait are presented. Total additive genetic correlations are near unity for most wing traits; this indicates that selection in the same direction in both sexes would have a minor effect on changing the magnitude of difference between sexes. Additive X-linked correlations suggest some genotype × sex interactions for X-linked effects.

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