scholarly journals Sexual selection gradients change over time in a simultaneous hermaphrodite

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jeroen NA Hoffer ◽  
Janine Mariën ◽  
Jacintha Ellers ◽  
Joris M Koene
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Mating Success ◽  
Time Window ◽  
Time Frame ◽  
Male Reproductive Success ◽  
Simultaneous Hermaphrodite ◽  
Selection Gradients ◽  
Short Time Window ◽  
Over Time

Sexual selection is generally predicted to act more strongly on males than on females. The Darwin-Bateman paradigm predicts that this should also hold for hermaphrodites. However, measuring this strength of selection is less straightforward when both sexual functions are performed throughout the organism’s lifetime. Besides, quantifications of sexual selection are usually done during a short time window, while many animals store sperm and are long-lived. To explore whether the chosen time frame affects estimated measures of sexual selection, we recorded mating success and reproductive success over time, using a simultaneous hermaphrodite. Our results show that male sexual selection gradients are consistently positive. However, an individual’s female mating success seems to negatively affect its own male reproductive success, an effect that only becomes visible several weeks into the experiment, highlighting that the time frame is crucial for the quantification and interpretation of sexual selection measures, an insight that applies to any iteroparous mating system.

scholarly journals The measure and significance of Bateman's principles

2014 ◽  
Vol 281 (1782) ◽  
pp. 20132973 ◽  
Author(s):  
Julie M. Collet ◽  
Rebecca F. Dean ◽  
Kirsty Worley ◽  
David S. Richardson ◽  
Tommaso Pizzari
Keyword(s):  
Reproductive Success ◽  
Mating Success ◽  
Male Reproductive Success ◽  
Female Fecundity ◽  
Male Preference ◽  
Bateman Gradient ◽  
Red Junglefowl ◽  
Experimental Approaches ◽  
Empirical Tests ◽  
Paternity Share

Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus , mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles.

scholarly journals 383. Feasibility of Specimen Self-collection in Young Children Undergoing SARS-CoV-2 Surveillance for In-person Learning

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S293-S293
Author(s):  
Jonathan Altamirano ◽  
Grace Tam ◽  
Marcela Lopez ◽  
India Robinson ◽  
Leanne Chun ◽  
...  
Keyword(s):  
Young Children ◽  
Time Window ◽  
School Administrators ◽  
Error Rates ◽  
Independent Observer ◽  
Specimen Collection ◽  
Timing Data ◽  
Short Time Window ◽  
Short Time ◽  
Over Time

Abstract Background While pediatric cases of COVID-19 are at low risk for adverse events, schoolchildren should be considered for surveillance as they can become infected at school and serve as sources of household or community transmission. Our team assessed the feasibility of young children self-collecting SARS-CoV-2 samples for surveillance testing in an educational setting. Methods Students at a K-8 school were tested weekly for SARS-CoV-2 from September 2020 - June 2021. Error rates were collected from September 2020 - January 2021. Clinical staff provided all students with instructions for anterior nares specimen self-collection and then observed them to ensure proper technique. Instructions included holding the sterile swab while making sure not to touch the tip, inserting the swab into their nostril until they start to feel resistance, and rubbing the swab in four circles before repeating the process in their other nostril. An independent observer timed random sample self-collections from April - June 2021. Results 2,590 samples were collected from 209 students during the study period when data on error rates were collected. Errors occurred in 3.3% of all student encounters (n=87). Error rates over time are shown in Figure 1, with the highest rate occurring on the first day of testing (n=20/197, 10.2%) and the lowest in January 2021 (n=1/202, 0.5%). 2,574 visits for sample self-collection occurred during the study period when independent timing data was collected (April - June 2021). Of those visits, 7.5% (n=193) were timed. The average duration of each visit was 70 seconds. Figure 1. Swab Error Rates Over Time Conclusion Pediatric self-collected lower nasal swabs are a viable and easily tolerated specimen collection method for SARS-CoV-2 surveillance in school settings, as evidenced by the low error rate and short time window of sample self-collection during testing. School administrators should expect errors to drop quickly after implementing testing. Disclosures All Authors: No reported disclosures

scholarly journals Insulin-insensitivity of male genitalia maintains reproductive success in Drosophila

2019 ◽  
Vol 15 (5) ◽  
pp. 20190057
Author(s):  
Austin P. Dreyer ◽  
Alexander W. Shingleton
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Male Genitalia ◽  
Male Reproductive Success ◽  
Evolutionary Mechanisms ◽  
Arthropod Species ◽  
Developmental Mechanisms ◽  
Negative Growth ◽  
Insulin Insensitivity ◽  
Male Genital

For most arthropod species, male genital size is relatively implastic in response to variation in developmental nutrition, such that the genitals in large well-fed males are similar in size to those in small poorly-fed males. In Drosophila melanogaster, reduced nutritional plasticity of the male genitalia is a consequence of low insulin sensitivity through a tissue-specific reduction in the expression of FOXO , a negative growth regulator . Despite an understanding of the proximate developmental mechanisms regulating organ size, the ultimate evolutionary mechanisms that may have led to reduced FOXO expression in the genitalia have not been fully elucidated. Here we show that restoring FOXO activity in the developing genitalia reduces the male genital size and decreases various aspects of male reproductive success. These data support the hypothesis that sexual selection has acted on the male genitalia to limit their nutritional plasticity through a reduction in FOXO expression, linking proximate with ultimate mechanisms of genital evolution.

scholarly journals Extrapair Paternity Increases Variability in Male Reproductive Success in the Chestnut-Sided Warbler (Dendroica Pensylvanica), A Socially Monogamous Songbird

The Auk ◽  
2004 ◽  
Vol 121 (3) ◽  
pp. 788-795
Author(s):  
Bruce E. Byers ◽  
Herman L. Mays ◽  
Ian R. K. Stewart ◽  
David F. Westneat
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Dna Typing ◽  
Bird Species ◽  
Male Reproductive Success ◽  
Extrapair Paternity ◽  
Bird Populations ◽  
Monogamous Species ◽  
Socially Monogamous ◽  
Dendroica Pensylvanica

Abstract A monogamous mating system that includes extrapair fertilization can potentially generate higher variability in male reproductive success than monogamy without extrapair fertilization. That increased variability could provide a correspondingly higher opportunity for sexual selection and, thus, for the origin and persistence of sexual dimorphism in monogamous species. To determine whether extrapair fertilization enhanced the opportunity for sexual selection in a sexually dimorphic, monogamous bird species, we used microsatellite DNA typing to assess the prevalence of extrapair fertilization and its effect on variation in male reproductive success in a population of Chestnut-sided Warblers (Dendroica pensylvanica). We found that the level of extrapair fertilization in our study population was at the upper end of the range reported for bird populations (47% of nestlings had extrapair fathers; 61% of broods contained extrapair offspring). We also discovered that almost all extrapair offspring were sired by paired males resident on nearby territories. In addition, we found that variation in male reproductive success was substantially higher than variation in female reproductive success, and that extrapair fertilizations made a significant contribution to variation in male reproductive success. Together, those findings suggest that extrapair fertilization creates an opportunity for sexual selection on male traits in this population.

scholarly journals Cyphoderris Strepitans (Orthoptera: Haglidae): Reproductive Biology and Geographical Distribution

1980 ◽  
Vol 4 ◽  
pp. 53-57
Author(s):  
Darryl Gwynne
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
National Parks ◽  
Egg Production ◽  
Paternal Care ◽  
Common Species ◽  
Male Reproductive Success ◽  
Male Investment ◽  
Cyphoderris Strepitans ◽  
Variance In Reproductive Success

Cyphoderris strepitans Morris and Gwynne is a common species of nocturnal insect in many sagebrush areas within Grand Tetons and Yellowstone National Parks. It is a primitive orthopteran group, a relict of the ancient family Haglidae. Only five species in three genera are currently known (Morris and Gwynne 1978, Storozhenko 1980). Males produce a calling song by rubbing their forewings together. Females are attracted to male song; during mating the female feeds on the tissues of the male's fleshy underwings. Virgin and non-virgin males can, therefore, be distinguished by examining their underwings. At the end of mating the male transfers a large proteinaceous spermatophore which the female also consumes. The main objective of this study has been to investigate the role and consequences of the male investment in his underwings and spermatophore (see Morris and Gwynne 1979). Female katydids use spermatophore proteins for egg production (Gwynne and Toalson unpublished) so these nutrients can be regarded as an important male investment likely to influence patterns of sexual selection within this group. Trivers (1972) outlined the theory of parental investment and its influence on sexual selection. Females, because they produce fewer larger gametes (eggs) are usually the limiting sex for the males which have a relatively large number of small gametes (sperm). As a result, males are predicted to maximize reproductive success by competing with each other to inseminate as many females as possible. Females, because they are limited by their fewer gametes will not gain by competing for copulations. Instead they should enhance reproductive success by being selective about which males fertilize their eggs. Sexual selection should, therefore, be stronger on males since competition for mates should produce a greater variance in the reproductive success of this sex (i.e., some males obtain few or no mates while others mate frequently). Males can offset the initial disparity of investment in gametes by investing parentally via paternal care of eggs or offspring or, as in many insects, by feeding the female with prey items or glandular products (Thornhill 1976). These sorts of male investments should decrease the variance in reproductive success of these males because the males are more "female like" in their reproductive strategy i.e., competing less because they reduce the number of potential copulations engaged in due to the large nutrient investment in each copulation. In orthopterans such as Cyphoderris where females feed on male-produced nutrients the following predictions emerge: (1) females should select a mate who is likely to provide more of the nutrient; (2) as mentioned above, the variance in male reproductive success should be low; few males should go unmated. Previous work in Grand Teton National Park has indicated that females may prefer Cyphoderris males who can supply more nutrients. Significantly more virgin males are mated than non-virgins (Morris and Gwynne 1979). Virgins are likely to be a better mate choice for females since they have not only more wing material but also would have large reproductive accessory glands capable of producing a full sized spermatophore. The main purpose of this season's work was to investigate the variance in reproductive success of males. An effort was also made to further collect information on the distribution of C. strepitans in and around Grand Teton and Yellowstone national parks. This information is presented first. (* Erratum: pp. 51 and 52 should be 56 and 57)

scholarly journals Nuclear arms races: experimental evolution for mating success in the mushroom-forming fungus Schizophyllum commune

2018 ◽  
Author(s):  
Bart P. S. Nieuwenhuis ◽  
Duur K. Aanen
Keyword(s):  
Sexual Selection ◽  
Mating Success ◽  
Experimental Evolution ◽  
Schizophyllum Commune ◽  
Spore Production ◽  
Pollen Competition ◽  
Male Reproductive Success ◽  
Competitive Fitness ◽  
Trade Offs ◽  
The One

SummaryWhen many gametes compete to fertilize a limited number of compatible gametes, sexual selection will favour traits that increase competitive success during mating. In animals and plants, sperm and pollen competition have yielded many interesting adaptations for improved mating success. In fungi, similar processes have not been shown directly yet. We test the hypothesis that sexual selection can increase competitive fitness during mating, using experimental evolution in the mushroom-forming fungus Schizophyllum commune (Basidiomycota). Mating in mushroom fungi occurs by donation of nuclei to a mycelium. These fertilizing ‘male’ nuclei migrate through the receiving ‘female’ mycelium. In our setup, an evolving population of nuclei was serially mated with a non-evolving female mycelium for 20 sexual generations. From the twelve tested evolved lines, four had increased and one had decreased fitness relative to an unevolved competitor. Even though only two of those five remained significant after correcting for multiple comparisons, for all five lines we found a correlation between the efficiency with which the female mycelium is accessed and fitness, providing additional circumstantial evidence for fitness change in those five lines. In two lines, fitness change was also accompanied by increased spore production. The one line with net reduced competitive fitness had increased spore production, but reduced fertilisation efficiency. We did not find trade-offs between male reproductive success and other fitness components. We compare these findings with examples of sperm and pollen competition and show that many similarities between these systems and nuclear competition in mushrooms exist.

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