The cost of realized sexual reproduction: assessing patterns of reproductive allocation and sporophyte abortion in a desert moss

2000 ◽  
Vol 87 (11) ◽  
pp. 1599-1608 ◽  
Author(s):  
Lloyd R. Stark ◽  
Brent D. Mishler ◽  
D. Nicholas McLetchie
Keyword(s):  
Sexual Reproduction ◽  
Reproductive Allocation ◽  
The Cost

The cost of reproduction to the clonal herb Asarum canadense (wild ginger)

1995 ◽  
Vol 73 (10) ◽  
pp. 1683-1686 ◽  
Author(s):  
Angela M. Muir
Keyword(s):  
Sexual Reproduction ◽  
Asexual Reproduction ◽  
Energy Cost ◽  
Reproductive Effort ◽  
Cost Of Reproduction ◽  
Net Energy ◽  
Subsequent Growth ◽  
Subsequent Storage ◽  
The Cost ◽  
And Storage

The cost of reproduction to the clonal understorey herb Asarum canadense (wild ginger) was examined by measuring subsequent growth and storage. All connected vegetative rhizome was controlled and fully measured. Three important aspects of reproductive effort were addressed: (i) the effect of sexual reproduction on subsequent storage and growth of fragments, (ii) the effect of asexual reproduction on subsequent storage and growth of fragments, and (iii) a comparison to determine the least costly method of reproduction. It was found that sexual reproduction in wild ginger has an energy cost that diverts energy from storage and growth. Asexual reproduction represents neither a net energy cost nor gain to the fragment and is the least costly mode of reproduction to wild ginger. Key words: Asarum canadense, reproduction, rhizome, clonal.

scholarly journals Same-sex sexual behavior and selection for indiscriminate mating

2020 ◽  
Author(s):  
Brian A Lerch ◽  
Maria R Servedio
Keyword(s):  
Sexual Behavior ◽  
Sexual Reproduction ◽  
Optimal Strategy ◽  
Strong Support ◽  
Same Sex ◽  
Evolutionary Origins ◽  
Wide Range ◽  
Selection For ◽  
The Cost ◽  
Time And Energy

The widespread presence of same-sex sexual behavior (SSB) has long been thought to pose an evolutionary conundrum1-3, as participants in SSB suffer the cost of failing to reproduce after expending the time and energy to find a mate. The potential for SSB to occur as part of an optimal strategy has received almost no attention, although indiscriminate sexual behavior may be the ancestral mode of sexual reproduction4. Here, we build a simple model of sexual reproduction and create a theoretical framework for the evolution of indiscriminate sexual behavior. We provide strong support for the hypothesis that SSB is likely maintained by selection for indiscriminate sexual behavior, by showing that indiscriminate mating is the optimal strategy under a wide range of conditions. Further, our model suggests that the conditions that most strongly favor indiscriminate mating were likely present at the origin of sexual behavior. These findings have implications not only for the evolutionary origins of SSB, but also for the evolution of discriminate sexual behavior across the animal kingdom.

One Final Word: Sex

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Sexual Reproduction ◽  
Kin Selection ◽  
Genetic Similarity ◽  
Best Interests ◽  
Evolution Of Sex ◽  
Sexual Generation ◽  
History Of ◽  
The Cost ◽  
And Behavior ◽  
Time And Energy

Sex transforms life. It affects morphology and behavior. It diverts enormous amounts of time and energy from the business of survival. It can even distract from the manufacture and safe packaging of offspring. The adolescent metamorphosis we each experience once, and thereafter view with amazement, in the relative calm of adulthood, has swept through nature on a grand scale, culminating in orchid flowers and peacock tails. All of this is due to chromosomal recombination—sex sensu strictu (Ghiselin, 1974)—and its organismal result, sexual reproduction or cooperation between two individuals to produce offspring. It is sex as sexual reproduction, the developmental side of sex that initiates the ontogeny of new individuals, that I mainly discuss here, though it is sex as recombination— the genetic side of sex—that has received most attention in discussions of the maintenance of sex. Of all the major transformations in the history of life, the evolution of sex is the most enigmatic. The question is not so much how sex got there as why it remains. Given the importance of genetic similarity, or kin selection (Hamilton, 1964a,b), for the maintenance of cooperation within and among organisms, sex seems designed to be disruptive. It requires the union of genetically dissimilar individuals, which dilutes the relatedness of mother and young, leaving the mother to invest in offspring genetically only half like herself. This has been called “the cost of meiosis” or the “twofold cost of sex” (Williams, 1975). It is a cost that usually falls to females, with their greater investment in eggs and care of offspring. By this view, the male is a parasite of his mate and participation in sexual reproduction is contrary to the best interests of females, who would do better to reproduce parthenogenetically on their own. Yet, among animals, only about one in one thousand species are thelytokous, that is, secondarily asexual, with no facultative or alternating sexual generation and no interaction with males. The prevalence of sexual reproduction in higher organisms is “inconsistent with current evolutionary theory” (Williams, 1975, p. v).

The adaptive function of sexual reproduction: resampling the pool of genotypic possibilities.

2021 ◽  
Author(s):  
Donal Hickey ◽  
Brian Golding
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Sexual Reproduction ◽  
Finite Population ◽  
Adaptive Function ◽  
Asexual Population ◽  
Sexual Population ◽  
Naturally Occurring ◽  
The Cost ◽  
The Universe

Abstract BackgroundNatural populations harbor significant levels of genetic variability. Because of this standing genetic variation, the number of possible genotypic combinations is many orders of magnitude greater than the population size. This means that any given population contains only a tiny fraction of all possible genotypic combinations.ResultsWe show that recombination allows a finite population to resample the genotype pool, i.e., the universe of all possible genotypic combinations. Recombination, in combination with natural selection, enables an evolving sexual population to replace existing genotypes with new, higher-fitness genotypic combinations that did not previously exist in the population. Gradually the selected sexual population approaches a state where the optimum genotype is produced by recombination and where it rises to fixation. In contrast to this, an asexual population is limited to selection among existing lower fitness genotypes.ConclusionsThe significance of the result is two-fold. First, it provides an explanation for the ubiquity of sexual reproduction in evolving populations. Secondly, it shows that recombination serves to remove concerns about the cost of natural selection acting on the naturally occurring standing genetic variation. This means that classic population genetics theory is applicable to ecological studies of natural selection acting on standing genetic variation.

Sexual Reproduction in Agaves: The Benefits of Bats; The Cost of Semelparous Advertising

Ecology ◽  
1981 ◽  
Vol 62 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. J. Howell ◽  
Barbara Schropfer Roth
Keyword(s):  
Sexual Reproduction ◽  
The Cost

scholarly journals Sex and the Evolution of Intrahost Competition in RNA Virus φ6

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 523-532 ◽  
Author(s):  
Paul E Turner ◽  
Lin Chao
Keyword(s):  
Sexual Reproduction ◽  
Rna Viruses ◽  
Rna Virus ◽  
Rapid Adaptation ◽  
Bacterial Host ◽  
Asexual Population ◽  
Sexual Population ◽  
Pseudomonas Phaseolicola ◽  
The Cost ◽  
Genetic Conflicts

Abstract Sex allows beneficial mutations that occur in separate lineages to be fixed in the same genome. For this reason, the Fisher-Muller model predicts that adaptation to the environment is more rapid in a large sexual population than in an equally large asexual population. Sexual reproduction occurs in populations of the RNA virus φ6 when multiple bacteriophages coinfect the same host cell. Here, we tested the model's predictions by determining whether sex favors more rapid adaptation of φ6 to a bacterial host, Pseudomonas phaseolicola. Replicate populations of φ6 were allowed to evolve in either the presence or absence of sex for 250 generations. All experimental populations showed a significant increase in fitness relative to the ancestor, but sex did not increase the rate of adaptation. Rather, we found that the sexual and asexual treatments also differ because intense intrahost competition between viruses occurs during coinfection. Results showed that the derived sexual viruses were selectively favored only when coinfection is common, indicating that within-host competition detracts from the ability of viruses to exploit the host. Thus, sex was not advantageous because the cost created by intrahost competition was too strong. Our findings indicate that high levels of coinfection exceed an optimum where sex may be beneficial to populations of φ6, and suggest that genetic conflicts can evolve in RNA viruses.

scholarly journals Sexual selection for rare beneficial mutations promotes the evolution of sexual reproduction and adaptation

2021 ◽  
Author(s):  
Gilbert Roberts ◽  
Marion Petrie
Keyword(s):  
Sexual Selection ◽  
Sexual Reproduction ◽  
Negative Impact ◽  
Reproductive Rate ◽  
Beneficial Mutations ◽  
Selection For ◽  
The Cost ◽  
Average Fitness ◽  
Cost Of Sex

The evolution and widespread maintenance of sexual reproduction remains a conundrum in biology because asexual reproduction should allow twice the reproductive rate. One hypothesis is that sexual selection lessens the negative impact on fitness of accumulating deleterious mutations. However, for adaptation to occur, there must also be selection for beneficial mutations. Here we show that sexual selection can help explain the evolution and maintenance of sexual reproduction. In our model, females chose males with more beneficial mutations (as opposed to just fewer harmful ones) even when these occurred much more rarely. Sexual selection thereby increased fixation of beneficial mutations which increased the absolute genetic quality of sexual offspring. This increase in fitness relative to asexual offspring adds to the previously postulated effect of reduced mutation load in offsetting the cost of sex. Analysing our simulations reveals that female choice among males raised the fitness of reproducing males above that of females. We found that this effect could overcome the decline in average fitness that occurs when mutation rate increases, allowing an increase in the fixation of beneficial mutations. Sexual selection thereby not only facilitates the evolution of sexual reproduction but maintains sex by leveraging its benefits and driving adaptation.

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