1
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Balfour VL, Armand M, Shuker DM. Is mating failure caused by cryptic male choice in the seed bug Lygaeus simulans? Ecol Evol 2024; 14:e70341. [PMID: 39296735 PMCID: PMC11410458 DOI: 10.1002/ece3.70341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 09/02/2024] [Accepted: 09/08/2024] [Indexed: 09/21/2024] Open
Abstract
One yet unresolved question in the study of mating system evolution is the occurrence of mating failure, when individuals go through their lives without successfully mating. This includes the failure to produce offspring even following copulation, for instance due to insemination or fertilisation failure. Copulations are costly in a variety of ways, but also a fundamental route to fitness in sexual species, and so we should expect that engaging in copulations that generate no offspring should be strongly selected against. Nonetheless, it has become apparent that mating failure is quite common in nature. Here we consider post-copulatory sexual selection in Lygaeus simulans seed bugs to test the hypothesis that the high levels of mating failure found in this species (approximately 40%-60%) are caused by cryptic male choice (i.e. males choosing not to inseminate a female during copulation). In our first experiment, we found that mating failure depended on female size, but not male size, with smaller females experiencing mating failure more frequently. Mechanistically this is likely to be due to copulation duration, as shorter copulations were more likely to lead to mating failure. Likewise, copulations with smaller females were shorter. In our second and third experiments, rates of mating failure decreased when pairs were allowed to repeatedly interact with the same partner over longer durations (hours through to days), implying that mating failure is not primarily caused by infertility or chronic mechanical failure. Instead, our results strongly suggest cryptic male choice as the cause of mating failure in this species.
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Affiliation(s)
| | - Mélissa Armand
- School of BiologyUniversity of St AndrewsSt AndrewsUK
- Department of Zoology and Evolutionary Biology, Animal Comparative Economics LaboratoryUniversity of RegensburgRegensburgGermany
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2
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Castano-Sanz V, Gomez-Mestre I, Rodriguez-Exposito E, Garcia-Gonzalez F. Pesticide exposure triggers sex-specific inter- and transgenerational effects conditioned by past sexual selection. Proc Biol Sci 2024; 291:20241037. [PMID: 39014998 PMCID: PMC11252676 DOI: 10.1098/rspb.2024.1037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 07/18/2024] Open
Abstract
Environmental variation often induces plastic responses in organisms that can trigger changes in subsequent generations through non-genetic inheritance mechanisms. Such transgenerational plasticity thus consists of environmentally induced non-random phenotypic modifications that are transmitted through generations. Transgenerational effects may vary according to the sex of the organism experiencing the environmental perturbation, the sex of their descendants or both, but whether they are affected by past sexual selection is unknown. Here, we use experimental evolution on an insect model system to conduct a first test of the involvement of sexual selection history in shaping transgenerational plasticity in the face of rapid environmental change (exposure to pesticide). We manipulated evolutionary history in terms of the intensity of sexual selection for over 80 generations before exposing individuals to the toxicant. We found that sexual selection history constrained adaptation under rapid environmental change. We also detected inter- and transgenerational effects of pesticide exposure in the form of increased fitness and longevity. These cross-generational influences of toxicants were sex dependent (they affected only male descendants), and intergenerational, but not transgenerational, plasticity was modulated by sexual selection history. Our results highlight the complexity of intra-, inter- and transgenerational influences of past selection and environmental stress on phenotypic expression.
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Affiliation(s)
- Veronica Castano-Sanz
- Department of Ecology and Evolution, Doñana Biological Station (CSIC), Seville, Spain
| | - Ivan Gomez-Mestre
- Department of Ecology and Evolution, Doñana Biological Station (CSIC), Seville, Spain
| | | | - Francisco Garcia-Gonzalez
- Department of Ecology and Evolution, Doñana Biological Station (CSIC), Seville, Spain
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, Western Australia, Australia
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3
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Siljestam M, Martinossi-Allibert I. Anisogamy Does Not Always Promote the Evolution of Mating Competition Traits in Males. Am Nat 2024; 203:230-253. [PMID: 38306281 DOI: 10.1086/727968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
AbstractAnisogamy has evolved in most sexually reproducing multicellular organisms allowing the definition of male and female sexes, producing small and large gametes. Anisogamy, as the initial sexual dimorphism, is a good starting point to understand the evolution of further sexual dimorphisms. For instance, it is generally accepted that anisogamy sets the stage for more intense mating competition in males than in females. We argue that this idea stems from a restrictive assumption on the conditions under which anisogamy evolved in the first place: the absence of sperm limitation (assuming that all female gametes are fertilized). Here, we relax this assumption and present a model that considers the coevolution of gamete size with a mating competition trait, starting in a population without dimorphism. We vary gamete density to produce different scenarios of gamete limitation. We show that while at high gamete density the evolution of anisogamy always results in male investment in competition, gamete limitation at intermediate gamete densities allows for either females or males to invest more into mating competition. Our results thus suggest that anisogamy does not always promote mating competition among males. The conditions under which anisogamy evolves matter, as does the competition trait.
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4
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Matzke M, Rossi A, Tuni C. Pre- and post-copulatory sexual selection increase offspring quality but impose survival costs to female field crickets. J Evol Biol 2023; 36:296-308. [PMID: 36484616 DOI: 10.1111/jeb.14132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/31/2022] [Accepted: 11/09/2022] [Indexed: 12/14/2022]
Abstract
Whether sexual selection increases or decreases fitness is under ongoing debate. Sexual selection operates before and after mating. Yet, the effects of each episode of selection on individual reproductive success remain largely unexplored. We ask how disentangled pre- and post-copulatory sexual selection contribute to fitness of field crickets Gryllus bimaculatus. Treatments allowed exclusively for (i) pre-copulatory selection, with males fighting and courting one female, and the resulting pair breeding monogamously, (ii) post-copulatory selection, with females mating consecutively to multiple males and (iii) relaxed selection, with enforced pair monogamy. While standardizing the number of matings, we estimated a number of fitness traits across treatments and show that females experiencing sexual selection were more likely to reproduce, their offspring hatched sooner, developed faster and had higher body mass at adulthood, but females suffered survival costs. Interestingly, we found no differences in fitness of females or their offspring from pre- and post-copulatory sexual selection treatments. Our findings highlight the potential for sexual selection in enhancing indirect female fitness while concurrently imposing direct survival costs. By potentially outweighing these costs, increased offspring quality could lead to beneficial population-level consequences of sexual selection.
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Affiliation(s)
| | - Aurora Rossi
- Ludwig Maximilian University of Munich, Munich, Germany
| | - Cristina Tuni
- Ludwig Maximilian University of Munich, Munich, Germany
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5
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Browne JH, Gwynne DT. Paternity sharing in insects with female competition for nuptial gifts. Ecol Evol 2022; 12:e9463. [PMID: 36329813 PMCID: PMC9618826 DOI: 10.1002/ece3.9463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/20/2022] [Accepted: 10/10/2022] [Indexed: 11/26/2022] Open
Abstract
Male parental investment is expected to be associated with high confidence of paternity. Studies of species with exclusive male parental care have provided support for this hypothesis because mating typically co-occurs with each oviposition, allowing control over paternity and the allocation of care. However, in systems where males invest by feeding mates (typically arthropods), mating (and thus the investment) is separated from egg-laying, resulting in less control over insemination, as male ejaculates compete with rival sperm stored by females, and a greater risk of investing in unrelated offspring (cuckoldry). As strong selection on males to increase paternity would compromise the fitness of all a female's other mates that make costly nutrient contributions, paternity sharing (males not excluded from siring offspring) is an expected outcome of sperm competition. Using wild-caught females in an orthopteran and a dipteran species, in which sexually selected, ornamented females compete for male nuptial food gifts needed for successful reproduction, we examined paternity patterns and compared them with findings in other insects. We used microsatellite analysis of offspring (lifetime reproduction in the orthopteran) and stored sperm from wild-caught females in both study species. As predicted, there was evidence of shared paternity as few males failed to sire offspring. Further support for paternity sharing is the lack of last-male sperm precedence in our study species. Although paternity was not equal among sires, our estimates of paternity bias were similar to other insects with valuable nuptial gifts and contrasted with the finding that males are frequently excluded from siring offspring in species where males supply little more than sperm. This suggests paternity bias may be reduced in nuptial-gift systems and may help facilitate the evolution of these paternal investments.
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Affiliation(s)
- Jessica H. Browne
- Department of Ecology and Evolutionary BiologyUniversity of Toronto MississaugaMississaugaOntarioCanada
- Department of BiologyMount Allison UniversitySackvilleNew BrunswickCanada
| | - Darryl T. Gwynne
- Department of Ecology and Evolutionary BiologyUniversity of Toronto MississaugaMississaugaOntarioCanada
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6
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Kobayashi H, Sato Y, Egas M. Males mate with females even after sperm depletion in the two-spotted spider mite. EXPERIMENTAL & APPLIED ACAROLOGY 2022; 86:465-477. [PMID: 35451696 DOI: 10.1007/s10493-022-00706-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Generally, males increase their reproductive success by mating with as many females as possible, whereas females increase their reproductive success by choosing males who provide more direct and indirect benefits. The difference in reproductive strategy between the sexes creates intense competition among males for access to females, therefore males spend much energy and time for competition with rival males for their reproduction. However, if they do not need to engage themselves into male competition and females are in no short supply, how many females can a male mate with and fertilize? We address this question in the two-spotted spider mite, Tetranychus urticae Koch. In this study, we investigated how many females a young, virgin male mated in 3 h, and checked whether the mated females were fertilized. We found that on average males mated with 12-13 females (range: 5-25). As latency to next mating did not change with the number of matings, the males are predicted to engage in even more matings if the mating trial were continued beyond 3 h. Copulation durations decreased with the number of matings and typically after 11 copulations with females any further copulations did not lead to fertilization, suggesting that males continued to mate with females even after sperm depletion. We discuss why spider mite males continue to display mating and copulation behaviour even after their sperm is depleted.
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Affiliation(s)
- Hisaho Kobayashi
- College of Biological Science, School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Yukie Sato
- Faculty of Life and Environmental Sciences/Mountain Science Center, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Martijn Egas
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
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7
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Matzke M, Toft S, Bechsgaard J, Pold Vilstrup A, Uhl G, Künzel S, Tuni C, Bilde T. Sperm competition intensity affects sperm precedence patterns in a polyandrous gift-giving spider. Mol Ecol 2022; 31:2435-2452. [PMID: 35178803 DOI: 10.1111/mec.16405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 01/26/2022] [Accepted: 02/08/2022] [Indexed: 11/28/2022]
Abstract
Sperm competition drives traits that enhance fertilization success. The amount of sperm transferred relative to competitors is key for attaining paternity. Female reproductive morphology and male mating order may also influence fertilization, however the outcome for sperm precedence under intense sperm competition remains poorly understood. In the polyandrous spider Pisaura mirabilis, males offer nuptial gifts which prolong copulation and increase sperm transfer, factors proposed to alter sperm precedence patterns under strong sperm competition. First, we assessed the degree of female polyandry by genotyping wild broods. A conservative analysis identified up to 4 sires, with a mean of 2 sires per brood, consistent with an optimal mating female rate. Then we asked whether intense sperm competition shifts sperm precedence patterns from first male priority, as expected from female morphology, to last male advantage. We varied sexual selection intensity experimentally and determined competitive fertilization outcome by genotyping broods. In double matings, one male monopolised paternity regardless of mating order. A mating order effect with first male priority was revealed when females were mated to 4 males, however this effect disappeared when females were mated to 6 males, likely due to increased sperm mixing. The proportion of males that successfully sired offspring drastically decreased with the number of competitors. Longer copulations translated into higher paternity shares independently of mating order, reinforcing the advantage of traits that prolong copulation duration under intense competition, such as the nuptial gift. Sperm competition intensity enhances the impact of competitive sexual traits and imposes multiple effects on paternity.
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Affiliation(s)
- Magdalena Matzke
- Department of Biology, Ludwig Maximilian University of Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Søren Toft
- Department of Biology, Aarhus University, Ny Munkegade 116, DK-8000, Aarhus C, Denmark
| | - Jesper Bechsgaard
- Department of Biology, Aarhus University, Ny Munkegade 116, DK-8000, Aarhus C, Denmark
| | - Astrid Pold Vilstrup
- Department of Biology, Aarhus University, Ny Munkegade 116, DK-8000, Aarhus C, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, DK-8000, Aarhus C, Denmark
| | - Gabriele Uhl
- General and Systematic Zoology, University of Greifswald, Zoological Institute and Museum, Loitzer Straße 26, D-17489, Greifswald, Germany
| | - Sven Künzel
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, August-Thienemann Straße 2, D-24306, Plön, Germany
| | - Cristina Tuni
- Department of Biology, Ludwig Maximilian University of Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Trine Bilde
- Department of Biology, Aarhus University, Ny Munkegade 116, DK-8000, Aarhus C, Denmark
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8
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Shuker DM, Kvarnemo C. The definition of sexual selection. Behav Ecol 2021; 32:781-794. [PMID: 34695172 PMCID: PMC8528540 DOI: 10.1093/beheco/arab055] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 05/05/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
Sexual selection is a key component of evolutionary biology. However, from the very formulation of sexual selection by Darwin, the nature and extent of sexual selection have been controversial. Recently, such controversy has led back to the fundamental question of just what sexual selection is. This has included how we incorporate female-female reproductive competition into sexual or natural selection. In this review, we do four things. First, we examine what we want a definition to do. Second, we define sexual selection: sexual selection is any selection that arises from fitness differences associated with nonrandom success in the competition for access to gametes for fertilization. An important outcome of this is that as mates often also offer access to resources, when those resources are the targets of the competition, rather than their gametes, the process should be considered natural rather than sexual selection. We believe this definition encapsulates both much of Darwin's original thinking about sexual selection, and much of how contemporary biologists use the concept of sexual selection. Third, we address alternative definitions, focusing in some detail on the role of female reproductive competition. Fourth, we challenge our definition with a number of scenarios, for instance where natural and sexual selection may align (as in some forms of endurance rivalry), or where differential allocation means teasing apart how fecundity and access to gametes influence fitness. In conclusion, we emphasize that whilst the ecological realities of sexual selection are likely to be complex, the definition of sexual selection is rather simple.
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Affiliation(s)
- David M Shuker
- School of Biology, Harold Mitchell Building, University of St. Andrews, St. Andrews, UK
| | - Charlotta Kvarnemo
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE, Sweden
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9
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Vasudeva R, Dickinson M, Sutter A, Powell S, Sales K, Gage M. Facultative polyandry protects females from compromised male fertility caused by heatwave conditions. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.05.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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10
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Rodriguez‐Exposito E, Garcia‐Gonzalez F. Metapopulation structure modulates sexual antagonism. Evol Lett 2021; 5:344-358. [PMID: 34367660 PMCID: PMC8327942 DOI: 10.1002/evl3.244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 01/19/2023] Open
Abstract
Despite the far-reaching evolutionary implications of sexual conflict, the effects of metapopulation structure, when populations are subdivided into several demes connected to some degree by migration, on sexual conflict dynamics are unknown. Here, we used experimental evolution in an insect model system, the seed beetle Callosobruchus maculatus, to assess the independent and interacting effects of selection histories associated with mating system (monogamy vs. polygamy) and population subdivision on sexual conflict evolution. We confirm traditional predictions from sexual conflict theory by revealing increased resistance to male harm in females from populations with a history of intense sexual selection (polygamous populations) compared to females from populations with a history of relaxed sexual selection (monogamous populations). However, selection arising from metapopulation structure reversed the classic pattern of sexually antagonistic coevolution and led to reduced resistance in females from polygamous populations. These results underscore that population spatial structure moderates sexual selection and sexual conflict, and more broadly, that the evolution of sexual conflict is contingent on ecological context. The findings also have implications for population dynamics, conservation biology, and biological control.
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Affiliation(s)
- E. Rodriguez‐Exposito
- Doñana Biological Station (EBD‐CSIC)Isla de la CartujaSevillaSpain
- Current address: Institute of Natural Products and Agrobiology (IPNA‐CSIC)Santa Cruz de TenerifeSpain
| | - F. Garcia‐Gonzalez
- Doñana Biological Station (EBD‐CSIC)Isla de la CartujaSevillaSpain
- Centre for Evolutionary Biology, School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
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11
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Yasui Y, Yamamoto Y. An empirical test of bet-hedging polyandry hypothesis in the field cricket Gryllus bimaculatus. J ETHOL 2021. [DOI: 10.1007/s10164-021-00707-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AbstractTheory shows that polyandry (mating with multiple males within a reproductive season) works as bet-hedging to increase the geometric mean fitness (GMF) of polyandrous genotype over generations and avoid extinction but it was rarely tested empirically. In this study, we distributed the eggs of Gryllus bimaculatus females mated with 1–4 males (mating treatment) into 4 petri dishes with different conditions: 25 °C/fresh water, 37 °C/fresh water, 25 °C/salt water, 37 °C/salt water, simulating 4 clutches laid at the different sites are suffered environmental change. The egg hatching rate was obtained over 7 blocks with different females for each mating treatment. In general, significantly more eggs hatched in 25 °C than 37 °C and in fresh water than salt water. The reproductive failure (no hatched eggs per petri dish) frequently occurred in monandry and 2-male polyandry. Next, we considered 7 blocks as the successive 7 virtual generations and calculated the within-generation arithmetic mean fitness (AMF) among females of the same treatment and the between-generation GMF of the AMF across 7 generations. Randomization test shows that the GMF of 3- and 4-male polyandry were significantly higher than monandry. This study shows that the risk from mating only once can be avoided by polyandrous mating as bet-hedging.
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12
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Matsumura K, Miyatake T, Yasui Y. An empirical test of the bet-hedging polyandry hypothesis: Female red flour beetles avoid extinction via multiple mating. Ecol Evol 2021; 11:5295-5304. [PMID: 34026007 PMCID: PMC8131809 DOI: 10.1002/ece3.7418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 02/16/2021] [Accepted: 02/24/2021] [Indexed: 11/11/2022] Open
Abstract
Bet-hedging via polyandry (spreading the extinction risk of the female's lineage over multiple males) may explain the evolution of female multiple mating, which is found in a wide range of animal and plant taxa. This hypothesis posits that females can increase their fitness via polyandrous mating when "unsuitable" males (i.e., males causing reproductive failure for various reasons) are frequent in the population and females cannot discriminate such unsuitable mates. Although recent theoretical studies have shown that polyandry can operate as a bet-hedging strategy, empirical tests are scarce. In the present study, we tested the bet-hedging polyandry hypothesis by using the red flour beetle Tribolium castaneum. We compared female reproductive success between monandry and polyandry treatments when females mated with males randomly collected from an experimental population, including 20% irradiated (infertile) males. In addition, we evaluated geometric mean fitness across multiple generations as the index of adaptability of bet-hedging traits. Polyandrous females showed a significantly higher egg hatching rate and higher geometric mean fitness than monandrous females. These results strongly support the bet-hedging polyandry hypothesis.
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Affiliation(s)
- Kentarou Matsumura
- Laboratory of EntomologyFaculty of AgricultureKagawa UniversityKagawaJapan
| | - Takahisa Miyatake
- Laboratory of Evolutionary EcologyGraduate School of Environmental and Life ScienceOkayama UniversityOkayamaJapan
| | - Yukio Yasui
- Laboratory of EntomologyFaculty of AgricultureKagawa UniversityKagawaJapan
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13
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Hare RM, Simmons LW. Sexual selection maintains a female-specific character in a species with dynamic sex roles. Behav Ecol 2021. [DOI: 10.1093/beheco/arab005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
The effects of sexual selection are more conspicuous among male animals, and, as a result, the majority of sexual selection research focuses on males. However, burgeoning evidence suggests that sexual selection also acts on females, and there have been calls for an increased focus on females. Here, we used a multivariate approach to analyze sexual selection in Kawanaphila nartee, a spermatophore gift-giving bushcricket with dynamic sex roles. Early in the breeding season, females compete for males, and, later, when environmental food resources are more abundant, sex roles revert to Darwinian convention. Ear size, which is much greater in females than in males, has been suggested to affect female fitness as females with larger ears are more likely to reach calling males first under sex-role-reversed conditions. We tested this suggestion and found evidence of positive linear and nonlinear correlational selection acting on female ear size early in the breeding season (under reversed sex roles) but not later in the breeding season (under Darwinian sex roles). Interestingly, there was no correlation between mating success and reproductive success (Bateman gradient) at any time during the season. Together, our results indicate that even brief and circumscribed periods of intrasexual competition among females can lead to sexual selection on morphological characters and that this selection may not depend on multiple mating. Considering the wealth of reports in the literature of brief episodes of intrasexual competition among female animals, we recommend increased study of sexual selection acting on females.
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Affiliation(s)
- Robin M Hare
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, Australia
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14
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Measuring Pre- and Post-Copulatory Sexual Selection and Their Interaction in Socially Monogamous Species with Extra-Pair Paternity. Cells 2021; 10:cells10030620. [PMID: 33799610 PMCID: PMC7999480 DOI: 10.3390/cells10030620] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 01/08/2023] Open
Abstract
When females copulate with multiple males, pre- and post-copulatory sexual selection may interact synergistically or in opposition. Studying this interaction in wild populations is complex and potentially biased, because copulation and fertilization success are often inferred from offspring parentage rather than being directly measured. Here, I simulated 15 species of socially monogamous birds with varying levels of extra-pair paternity, where I could independently cause a male secondary sexual trait to improve copulation success, and a sperm trait to improve fertilization success. By varying the degree of correlation between the male and sperm traits, I show that several common statistical approaches, including univariate selection gradients and paired t-tests comparing extra-pair males to the within-pair males they cuckolded, can give highly biased results for sperm traits. These tests should therefore be avoided for sperm traits in socially monogamous species with extra-pair paternity, unless the sperm trait is known to be uncorrelated with male trait(s) impacting copulation success. In contrast, multivariate selection analysis and a regression of the proportion of extra-pair brood(s) sired on the sperm trait of the extra-pair male (including only broods where the male sired ≥1 extra-pair offspring) were unbiased, and appear likely to be unbiased under a broad range of conditions for this mating system. In addition, I investigated whether the occurrence of pre-copulatory selection impacted the strength of post-copulatory selection, and vice versa. I found no evidence of an interaction under the conditions simulated, where the male trait impacted only copulation success and the sperm trait impacted only fertilization success. Instead, direct selection on each trait was independent of whether the other trait was under selection. Although pre- and post-copulatory selection strength was independent, selection on the two traits was positively correlated across species because selection on both traits increased with the frequency of extra-pair copulations in these socially monogamous species.
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15
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Polak M, Hurtado-Gonzales JL, Benoit JB, Hooker KJ, Tyler F. Positive genetic covariance between male sexual ornamentation and fertilizing capacity. Curr Biol 2021; 31:1547-1554.e5. [PMID: 33567290 DOI: 10.1016/j.cub.2021.01.046] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/15/2020] [Accepted: 01/13/2021] [Indexed: 12/16/2022]
Abstract
Postcopulatory sexual selection results from variation in competitive fertilization success among males and comprises powerful evolutionary forces that operate after the onset of mating.1,2 Theoretical advances in the field of sexual selection addressing the buildup and coevolutionary consequences of genetic coupling3-5 motivate the hypothesis that indirect postcopulatory sexual selection may promote evolution of male secondary sexual traits-those traits traditionally ascribed to mate choice and male fighting.6,7 A crucial prediction of this hypothesis is genetic covariance between trait expression and competitive fertilization success, which has been predicted to arise, for example, when traits subject to pre- and postcopulatory sexual selection are under positive correlational selection.8 We imposed bidirectional artificial selection on male ornament (sex comb) size in Drosophila bipectinata and demonstrated increased competitive fertilization success as a correlated evolutionary response to increasing ornament size. Transcriptional analyses revealed that levels of specific seminal fluid proteins repeatedly shifted in response to this selection, suggesting that properties of the ejaculate, rather than the enlarged sex comb itself, contributed fertilizing capacity. We used ultraprecise laser surgery to reduce ornament size of high-line males and found that their fertilizing superiority persisted despite the size reduction, reinforcing the transcriptional results. The data support the existence of positive genetic covariance between a male secondary sexual trait and competitive fertilization success, and suggest the possibility that indirect postcopulatory sexual selection may, under certain conditions, magnify net selection on ornamental trait expression.
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Affiliation(s)
- Michal Polak
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA.
| | | | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
| | - Kassie J Hooker
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
| | - Frances Tyler
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
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16
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Lewis RC, Pointer MD, Friend LA, Vasudeva R, Bemrose J, Sutter A, Gage MJG, Spurgin LG. Polyandry provides reproductive and genetic benefits in colonising populations. Ecol Evol 2020; 10:10851-10857. [PMID: 33072300 PMCID: PMC7548180 DOI: 10.1002/ece3.6742] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 11/10/2022] Open
Abstract
Polyandry, when females mate with more than one male, is theorised to play an important role in successful colonisation of new habitats. In addition to possible benefits from sexual selection, even mild polyandry could facilitate colonisation by protecting against inbreeding and reducing the costs of mating with incompatible or infertile males. Here, we measure the importance of mild polyandry for population viability and reproductive fitness following experimental founder events into a higher‐temperature regime. Using colonisation experiments with the model beetle Tribolium castaneum, in which females can produce offspring for up to 140 days following a single mating, we founded more than 100 replicate populations using single females that had been given the opportunity to mate with either one or two males and then tracked their subsequent population dynamics. Following population viability and fitness across 10 generations, we found that extinction rates were significantly lower in populations founded by females given polyandrous opportunities to mate with two males (9%) compared to populations founded by monogamous females (34%). In addition, populations founded by females that had been provided with opportunities to store sperm from two different males showed double the median productivity following colonisation compared to monogamous‐founded populations. Notably, we identified short‐term and longer‐term benefits to post‐colonisation populations from double‐mating, with results suggesting that polyandry acts to both protect against mating with incompatible males through the founder event, and reduce inbreeding depression as the colonisation proceeds for 10 generations. Our results therefore show that even mild polyandry provides both reproductive and genetic benefits for colonising populations.
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Affiliation(s)
- Rebecca C Lewis
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Michael D Pointer
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Lucy A Friend
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Ramakrishnan Vasudeva
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - James Bemrose
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Andreas Sutter
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Matthew J G Gage
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
| | - Lewis G Spurgin
- School of Biological Sciences Norwich Research Park University of East Anglia Norwich UK
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17
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Fisher AM, Cornell SJ, Holwell GI, Price TAR. Mate‐finding Allee effects can be exacerbated or relieved by sexual cannibalism. J Anim Ecol 2020; 89:1581-1592. [DOI: 10.1111/1365-2656.13214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 02/21/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Adam M. Fisher
- Institute of Integrative Biology University of Liverpool Liverpool UK
| | | | | | - Tom A. R. Price
- Institute of Integrative Biology University of Liverpool Liverpool UK
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18
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Cingolani MF, Roggiero MF, Barakat MC, Liljesthröm GG. Polyandry and trade-off between fecundity and longevity in female Dichelops furcatus (Hemiptera: Pentatomidae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2020; 110:155-160. [PMID: 31244455 DOI: 10.1017/s0007485319000427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A trade-off is a relationship between two life history characteristics principally reproduction and adult longevity that are fundamental in predicting the optimal life history in any given environment. Mating is indispensable for sexual reproduction, but also can impose risks to females. Nevertheless, in the majority of insects, females allow multiple mating. Dichelops furcatus (Hemiptera: Pentatomidae) is a pest of wheat and corn in Argentina and southern Brazil, but little is known about its reproduction (i.e., the characteristics of the process that results in offspring). We analyzed reproductive attributes of D. furcatus, and the effect of single mating vs. multiple matings, evaluating the trade-off between fecundity and adult female longevity. We found that mating is not required for D. furcatus to oviposit, and multiple copulations were costly in terms of reduced longevity. Although multicopulated females lived a shorter period, only the pre- and post-reproductive periods were shortened. Fecundity was not affected but fertility was incremented in multicopulated females. Females copulated only once oviposited most of the eggs in the first half of the reproductive period, while eggs oviposited in the second half were all inviable (did not hatch). Studying demographic attributes of phytophagous insects provides relevant information to better understand the population dynamics of pests.
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Affiliation(s)
- M F Cingolani
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE) (CONICET - UNLP. Centro Asociado CIC), Boulevard 120s/n entre 60 y 64 (1900), La Plata, Argentina
| | - M F Roggiero
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE) (CONICET - UNLP. Centro Asociado CIC), Boulevard 120s/n entre 60 y 64 (1900), La Plata, Argentina
| | - M C Barakat
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE) (CONICET - UNLP. Centro Asociado CIC), Boulevard 120s/n entre 60 y 64 (1900), La Plata, Argentina
| | - G G Liljesthröm
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE) (CONICET - UNLP. Centro Asociado CIC), Boulevard 120s/n entre 60 y 64 (1900), La Plata, Argentina
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19
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Abstract
Abstract
Estimates of last male sperm precedence (P2) are often used to infer mechanisms of sperm competition, a form of post-copulatory sexual selection. However, high levels of mating failure (i.e. copulations resulting in no offspring) in a population can lead to misinterpretations of sperm competition mechanisms. Through simulations, García-González (2004) illustrated how mating failure could cause bimodal distributions of paternity with peaks at P2 = 0 and 1, under a random sperm mixing mechanism. Here, we demonstrate this effect empirically with the seed bug Lygaeus simulans, a species known to exhibit high levels of mating failure (40–60%), using a morphological marker to estimate paternity. Contrary to previous findings in a sister species, we did not find strong evidence for last male sperm precedence. There was a tendency towards last male precedence (P2 = 0.58) but within the expected range for random sperm mixing. Instead, P2 was highly variable, with a bimodal distribution, as predicted by García-González (2004). After taking mating failure into account, the strongest driver of paternity outcome was copulation duration. Furthermore, we found evidence that mating failure could partly be a female-associated trait. Some doubly-mated females were more likely to produce no offspring or produce offspring from two different sires than expected by chance. Therefore, some females are more prone to experience mating failure than others, a result that mirrors an earlier result in male L. simulans. Our results confirm that mating failure needs to be considered when interrogating mechanisms of post-copulatory sexual selection.
Significance statement
Mating failure arises when animals fail to produce offspring across their lifetime. This may be due to a failure to find a mate or a failure to produce offspring after one or more apparently successful matings. Sperm competition is when ejaculates of rival males compete to fertilize a female’s eggs. Estimates of second male paternity (P2) are often used to infer mechanisms of sperm competition (i.e. which male “wins” and how). However, García-González (2004) suggested that high levels of mating failure can skew paternity (i.e. give spuriously high/low levels of P2) and lead to misinterpretations of these mechanisms. We carried out sperm competition experiments on Lygaeus simulans seed bugs using a morphological marker to estimate paternity. We show empirically that mating failure does skew patterns of paternity, causing a bimodal distribution of P2. Therefore, by disrupting patterns of sperm competition, mating failure influences both the action of post-copulatory sexual selection and also our understanding of the mechanisms of sperm competition.
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20
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Msaad Guerfali M, Chevrier C. Determinant factors for sperm transfer and sperm storage within Ceratitis capitata (Diptera: Tephritidae) and impact on Sterile Insect Technique. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2020. [DOI: 10.1080/16878507.2020.1855901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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21
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Rodriguez‐Exposito E, Garcia‐Gonzalez F, Polak M. Individual and synergistic effects of male external genital traits in sexual selection. J Evol Biol 2019; 33:67-79. [DOI: 10.1111/jeb.13546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/15/2019] [Accepted: 09/19/2019] [Indexed: 01/22/2023]
Affiliation(s)
| | - Francisco Garcia‐Gonzalez
- Doñana Biological Station (CSIC) Sevilla Spain
- Centre for Evolutionary Biology School of Biological Sciences The University of Western Australia Crawley WA Australia
| | - Michal Polak
- Department of Biological Sciences University of Cincinnati Cincinnati OH USA
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22
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Sutter A, Travers LM, Oku K, L. Delaney K, J. Store S, Price TAR, Wedell N. Flexible polyandry in female flies is an adaptive response to infertile males. Behav Ecol 2019. [DOI: 10.1093/beheco/arz140] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Abstract
Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for polyandry, but whether and how it actually contributes to the evolution of polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura, and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible polyandry, but is less likely to cause an increase in genetic polyandry.
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Affiliation(s)
- Andreas Sutter
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, UK, and
| | - Laura M Travers
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich, UK, and
| | - Keiko Oku
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
| | - Kynan L. Delaney
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
| | - Stefan J. Store
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
| | - Tom A R Price
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Nina Wedell
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Penryn, UK
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23
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Buzatto BA, Kotiaho JS, Assis LAF, Simmons LW. A link between heritable parasite resistance and mate choice in dung beetles. Behav Ecol 2019. [DOI: 10.1093/beheco/arz089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AbstractParasites play a central role in the adaptiveness of sexual reproduction. Sexual selection theory suggests a role for parasite resistance in the context of mate choice, but the evidence is mixed. The parasite-mediated sexual selection (PMSS) hypothesis derives a number of predictions, among which that resistance to parasites is heritable, and that female choice favors parasite resistance genes in males. Here, we tested the PMSS hypothesis using the dung beetle Onthophagus taurus, a species that can be heavily parasitized by Macrocheles merdarius mites, which are known to affect adult survival. We investigated the heritability of resistance to M. merdarius, as well as whether female O. taurus impose a mating bias against males susceptible to mite infestation. Female choice for parasite resistance is difficult to disentangle from the possibility that females are simply choosing less parasitized males due to naturally selected benefits of avoiding contracting those parasites. This is especially likely for ectoparasites, such as mites. We tackled this problem by performing a mate choice trial first, and then measuring a male’s resistance to mite infestation. Resistance to mite infestation exhibited significant levels of additive genetic variance. Although we found no relationship between mating success and parasite resistance, males with greater resistance to infestation mated for longer. If females control copula duration, given that short copulations often result in mating failure, female choice could act on parasite resistance.
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Affiliation(s)
- Bruno A Buzatto
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, WA, Australia
- Department of Biological Sciences (E8C 209), Macquarie University, Sydney, NSW, Australia
| | - Janne S Kotiaho
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- School of Resource Wisdom, University of Jyväskylä, Jyväskylä, Finland
| | - Larissa A F Assis
- Departamento de Ecologia, Instituto de Biociências, Rua do Matão, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, Crawley, WA, Australia
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24
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McNamara KB, Dougherty LR, Wedell N, Simmons LW. Experimental evolution reveals divergence in female genital teeth morphology in response to sexual conflict intensity in a moth. J Evol Biol 2019; 32:519-524. [DOI: 10.1111/jeb.13428] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/31/2019] [Accepted: 02/11/2019] [Indexed: 01/01/2023]
Affiliation(s)
- Kathryn B. McNamara
- Centre for Evolutionary Biology School of Biological Sciences (M092) the University of Western Australia Crawley Australia
| | - Liam R. Dougherty
- Institute of Integrative Biology University of Liverpool Liverpool UK
| | - Nina Wedell
- Centre for Ecology and Conservation University of Exeter Penryn UK
| | - Leigh W. Simmons
- Centre for Evolutionary Biology School of Biological Sciences (M092) the University of Western Australia Crawley Australia
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25
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Pizzari T, McDonald GC. Sexual selection in socially-structured, polyandrous populations: Some insights from the fowl. ADVANCES IN THE STUDY OF BEHAVIOR 2019. [DOI: 10.1016/bs.asb.2019.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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26
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Hare RM, Simmons LW. Sexual selection and its evolutionary consequences in female animals. Biol Rev Camb Philos Soc 2018; 94:929-956. [DOI: 10.1111/brv.12484] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Robin M. Hare
- Centre for Evolutionary Biology, School of Biological Sciences University of Western Australia 35 Stirling Highway, Perth, 6009 Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological Sciences University of Western Australia 35 Stirling Highway, Perth, 6009 Australia
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27
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Yuta T, Nomi D, Ihle M, Koizumi I. Simulated hatching failure predicts female plasticity in extra-pair behavior over successive broods. Behav Ecol 2018. [DOI: 10.1093/beheco/ary124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Teru Yuta
- Yamashina Institute for Ornithology, Abiko, Japan
| | - Daisuke Nomi
- Graduate School of Environment Science, Hokkaido University, Sapporo, Japan
| | - Malika Ihle
- Entomology and Nematology Department, University of Florida, Gainesville, USA
| | - Itsuro Koizumi
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Japan
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28
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Scarponi V, Godin JGJ. Female assessment of male functional fertility during mate choice in a promiscuous fish. Ethology 2018. [DOI: 10.1111/eth.12723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Valentina Scarponi
- Department of Biology; Carleton University; Ottawa ON Canada
- Department of Life Sciences; University of Sussex; Brighton UK
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29
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Bocedi G, Reid JM. Feed-backs among inbreeding, inbreeding depression in sperm traits, and sperm competition can drive evolution of costly polyandry. Evolution 2017; 71:2786-2802. [PMID: 28895138 PMCID: PMC5765454 DOI: 10.1111/evo.13363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/28/2017] [Accepted: 08/31/2017] [Indexed: 11/28/2022]
Abstract
Ongoing ambitions are to understand the evolution of costly polyandry and its consequences for species ecology and evolution. Emerging patterns could stem from feed-back dynamics between the evolving mating system and its genetic environment, defined by interactions among kin including inbreeding. However, such feed-backs are rarely considered in nonselfing systems. We use a genetically explicit model to demonstrate a mechanism by which inbreeding depression can select for polyandry to mitigate the negative consequences of mating with inbred males, rather than to avoid inbreeding, and to elucidate underlying feed-backs. Specifically, given inbreeding depression in sperm traits, costly polyandry evolved to ensure female fertility, without requiring explicit inbreeding avoidance. Resulting sperm competition caused evolution of sperm traits and further mitigated the negative effect of inbreeding depression on female fertility. The evolving mating system fed back to decrease population-wide homozygosity, and hence inbreeding. However, the net overall decrease was small due to compound effects on the variances in sex-specific reproductive success and paternity skew. Purging of deleterious mutations did not eliminate inbreeding depression in sperm traits or hence selection for polyandry. Overall, our model illustrates that polyandry evolution, both directly and through sperm competition, might facilitate evolutionary rescue for populations experiencing sudden increases in inbreeding.
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Affiliation(s)
- Greta Bocedi
- School of Biological SciencesUniversity of AberdeenZoology BuildingTillydrone AvenueAberdeen AB24 2TZUnited Kingdom
| | - Jane M. Reid
- School of Biological SciencesUniversity of AberdeenZoology BuildingTillydrone AvenueAberdeen AB24 2TZUnited Kingdom
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30
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Bet-hedging against male-caused reproductive failures may explain ubiquitous cuckoldry in female birds. J Theor Biol 2017; 437:214-221. [PMID: 29107613 DOI: 10.1016/j.jtbi.2017.10.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 10/27/2017] [Accepted: 10/27/2017] [Indexed: 11/23/2022]
Abstract
The origin and maintenance of polyandry is one of the key unresolved questions in evolutionary biology. In particular, extra-pair paternity (EPP) due to polyandry is observed in most (socially-) monogamous female birds and the frequency of EPP is surprisingly high (up to 72% in a clutch on average in some species). Many case-by-case hypotheses have been presented to explain this phenomenon but a ubiquitous explanation is still lacking. One possible general explanation is bet-hedging, which is a strategy to avoid the risk associated to mating with a single unsuitable male and thus to minimize the chances of complete reproductive failure by the female. Here, we present a mathematical solution to demonstrate that bet-hedging polyandry becomes highly effective if the risk of extinction of a female lineage attributable to male deficiencies is high in small subpopulation or under limited mate availability. Therefore, cuckoldry or polyandry may be a female strategy to spread the risk of extinction of her genotype over multiple males. The results agree well with the observed EPP frequencies in natural populations and the results of a meta-population simulation model. Our theory contributes new insights applicable not only to birds but also to a broad taxonomic range of animals.
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31
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(Ginny) Greenway E, Balfour VL, Shuker DM. Can females choose to avoid mating failure in the seed bug Lygaeus simulans? Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Evans JP, Garcia-Gonzalez F. The total opportunity for sexual selection and the integration of pre- and post-mating episodes of sexual selection in a complex world. J Evol Biol 2016; 29:2338-2361. [PMID: 27520979 DOI: 10.1111/jeb.12960] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 12/30/2022]
Abstract
It is well known that sexual selection can target reproductive traits during successive pre- and post-mating episodes of selection. A key focus of recent studies has been to understand and quantify how these episodes of sexual selection interact to determine overall variance in reproductive success. In this article, we review empirical developments in this field but also highlight the considerable variability in patterns of pre- and post-mating sexual selection, attributable to variation in patterns of resource acquisition and allocation, ecological and social factors, genotype-by-environment interaction and possible methodological factors that might obscure such patterns. Our aim is to highlight how (co)variances in pre- and post-mating sexually selected traits can be sensitive to changes in a range of ecological and environmental variables. We argue that failure to capture this variation when quantifying the opportunity for sexual selection may lead to erroneous conclusions about the strength, direction or form of sexual selection operating on pre- and post-mating traits. Overall, we advocate for approaches that combine measures of pre- and post-mating selection across contrasting environmental or ecological gradients to better understand the dynamics of sexual selection in polyandrous species. We also discuss some directions for future research in this area.
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Affiliation(s)
- J P Evans
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Crawley, WA, Australia
| | - F Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Crawley, WA, Australia.,Doñana Biological Station, Spanish Research Council CSIC, Sevilla, Spain
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33
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McNamara KB, Robinson SP, Rosa ME, Sloan NS, van Lieshout E, Simmons LW. Male-biased sex ratio does not promote increased sperm competitiveness in the seed beetle, Callosobruchus maculatus. Sci Rep 2016; 6:28153. [PMID: 27306351 PMCID: PMC4910101 DOI: 10.1038/srep28153] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/27/2016] [Indexed: 11/09/2022] Open
Abstract
Sperm competition risk and intensity can select for adaptations that increase male fertilisation success. Evolutionary responses are examined typically by generating increased strength of sexual selection via direct manipulation of female mating rates (by enforcing monandry or polyandry) or by alteration of adult sex ratios. Despite being a model species for sexual selection research, the effect of sexual selection intensity via adult sex-ratio manipulation on male investment strategies has not been investigated in the seed beetle, Callosobruchus maculatus. We imposed 32 generations of experimental evolution on 10 populations of beetles by manipulating adult sex ratio. Contrary to predictions, males evolving in male-biased populations did not increase their testes and accessory gland size. This absence of divergence in ejaculate investment was also reflected in the fact that males from male-biased populations were not more successful in either preventing females from remating, or in competing directly for fertilisations. These populations already demonstrate divergence in mating behaviour and immunity, suggesting sufficient generations have passed to allow divergence in physiological and behavioural traits. We propose several explanations for the absence of divergence in sperm competitiveness among our populations and the pitfalls of using sex ratio manipulation to assess evolutionary responses to sexual selection intensity.
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Affiliation(s)
- Kathryn B McNamara
- Centre for Evolutionary Biology, School of Animal Biology (M092), the University of Western Australia, Crawley, 6009, Australia
| | - Stephen P Robinson
- Centre for Evolutionary Biology, School of Animal Biology (M092), the University of Western Australia, Crawley, 6009, Australia
| | - Márta E Rosa
- Department of Evolutionary Zoology and Human Biology, University of Debrecen, Debrecen, H-4032, Hungary.,Department of Ecology, Szent István University, Budapest, H-1077, Hungary
| | - Nadia S Sloan
- Centre for Evolutionary Biology, School of Animal Biology (M092), the University of Western Australia, Crawley, 6009, Australia
| | - Emile van Lieshout
- Centre for Evolutionary Biology, School of Animal Biology (M092), the University of Western Australia, Crawley, 6009, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Animal Biology (M092), the University of Western Australia, Crawley, 6009, Australia
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34
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Breedveld MC, Fitze PS. Experimental evidence that sperm maturation drives protandry in an ectotherm. Oecologia 2016; 182:129-37. [DOI: 10.1007/s00442-016-3668-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/27/2016] [Indexed: 11/30/2022]
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35
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36
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Travers LM, Garcia-Gonzalez F, Simmons LW. Genetic variation but weak genetic covariation between pre- and post-copulatory episodes of sexual selection in Drosophila melanogaster. J Evol Biol 2016; 29:1535-52. [PMID: 27159063 DOI: 10.1111/jeb.12890] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/20/2016] [Accepted: 04/29/2016] [Indexed: 12/16/2022]
Abstract
When females mate polyandrously, male reproductive success depends both on the male's ability to attain matings and on his ability to outcompete rival males in the fertilization of ova post-copulation. Increased investment in ejaculate components may trade off with investment in precopulatory traits due to resource allocation. Alternatively, pre- and post-copulatory traits could be positively related if individuals can afford to invest heavily in traits advantageous at both episodes of selection. There is empirical evidence for both positive and negative associations between pre- and post-copulatory episodes, but little is known about the genetic basis of these correlations. In this study, we measured morphological, chemical and behavioural precopulatory male traits and investigated their relationship with measures of male fitness (male mating success, remating inhibition and offensive sperm competitiveness) across 40 isofemale lines of Drosophila melanogaster. We found significant variation among isofemale lines, indicating a genetic basis for most of the traits investigated. However, we found weak evidence for genetic correlations between precopulatory traits and our indices of male fitness. Moreover, pre- and post-copulatory episodes of selection were uncorrelated, suggesting selection may act independently at the different episodes to maximize male reproductive success.
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Affiliation(s)
- L M Travers
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
| | - F Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia.,Doñana Biological Station, Spanish Research Council CSIC, Isla de la Cartuja, Seville, Spain
| | - L W Simmons
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
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37
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Worthington AM, Kelly CD. Direct costs and benefits of multiple mating: Are high female mating rates due to ejaculate replenishment? Behav Processes 2016; 124:115-22. [DOI: 10.1016/j.beproc.2015.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/22/2015] [Indexed: 01/22/2023]
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38
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Travers LM, Simmons LW, Garcia‐Gonzalez F. Additive genetic variance in polyandry enables its evolution, but polyandry is unlikely to evolve through sexy or good sperm processes. J Evol Biol 2016; 29:916-28. [DOI: 10.1111/jeb.12834] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/15/2016] [Indexed: 02/03/2023]
Affiliation(s)
- L. M. Travers
- Centre for Evolutionary Biology School of Animal Biology (M092) The University of Western Australia Crawley WA Australia
| | - L. W. Simmons
- Centre for Evolutionary Biology School of Animal Biology (M092) The University of Western Australia Crawley WA Australia
| | - F. Garcia‐Gonzalez
- Centre for Evolutionary Biology School of Animal Biology (M092) The University of Western Australia Crawley WA Australia
- Doñana Biological Station Spanish Research Council CSIC Sevilla Spain
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39
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Bocedi G, Reid JM. Coevolutionary Feedbacks between Female Mating Interval and Male Allocation to Competing Sperm Traits Can Drive Evolution of Costly Polyandry. Am Nat 2016; 187:334-50. [PMID: 26913946 DOI: 10.1086/684746] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Complex coevolutionary feedbacks between female mating interval and male sperm traits have been hypothesized to explain the evolution and persistence of costly polyandry. Such feedbacks could potentially arise because polyandry creates sperm competition and consequent selection on male allocation to sperm traits, while the emerging sperm traits could create female sperm limitation and, hence, impose selection for increased polyandry. However, the hypothesis that costly polyandry could coevolve with male sperm dynamics has not been tested. We built a genetically explicit individual-based model to simulate simultaneous evolution of female mating interval and male allocation to sperm number versus longevity, where these two sperm traits trade off. We show that evolution of competing sperm traits under polyandry can indeed cause female sperm limitation and, hence, promote further evolution and persistence of costly polyandry, particularly when sperm are costly relative to the degree of female sperm limitation. These feedbacks were stronger, and greater polyandry evolved, when postcopulatory competition for paternity followed a loaded rather than fair raffle and when sperm traits had realistically low heritability. We therefore demonstrate that the evolution of allocation to sperm traits driven by sperm competition can prevent males from overcoming female sperm limitation, thereby driving ongoing evolution of costly polyandry.
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40
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Yasui Y, Garcia-Gonzalez F. Bet-hedging as a mechanism for the evolution of polyandry, revisited. Evolution 2016; 70:385-97. [PMID: 26748458 DOI: 10.1111/evo.12847] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 12/29/2015] [Accepted: 12/31/2015] [Indexed: 11/30/2022]
Abstract
Females that mate with multiple males (polyandry) may reduce the risk that their eggs are fertilized by a single unsuitable male. About 25 years ago it was hypothesized that bet-hedging could function as a mechanism favoring the evolution of polyandry, but this idea is controversial because theory indicates that bet-hedging via polyandry can compensate the costs of mating only in small populations. Nevertheless, populations are often spatially structured, and even in the absence of spatial structure, mate-choice opportunity can be limited to a few potential partners. We examined the effectiveness of bet-hedging in such situations with simulations carried out under two scenarios: (1) intrinsic male quality, with offspring survival determined by male phenotype (male's ability to generate viable offspring), and (2) genetic incompatibility (offspring fitness determined nonadditively by parental genotypes). We find higher fixation probabilities for a polyandrous strategy compared to a monandrous strategy if complete reproductive failure due to male effects or parental incompatibility is pervasive in the population. Our results also indicate that bet-hedging polyandry can delay the extinction of small demes. Our results underscore the potential for bet-hedging to provide benefits to polyandrous females and have valuable implications for conservation biology.
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Affiliation(s)
- Yukio Yasui
- Laboratory of Entomology, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, 761-0795, Japan. ,
| | - Francisco Garcia-Gonzalez
- Doñana Biological Station, Spanish Research Council CSIC, C/ Americo Vespucio s/n, 41092, Isla de la Cartuja, Seville, Spain.,Centre for Evolutionary Biology, School of Animal Biology, The University of Western Australia, Nedlands, WA, 6009, Australia
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41
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Breedveld MC, Fitze PS. The timing and interval of mate encounter affects investment during mating. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Merel C. Breedveld
- Instituto Pirenaico de Ecología (IPE-CSIC); Avda Nuestra Señora de la Victoria 16 22700 Jaca Spain
- Department of Biodiversity and Evolutionary Biology; Museo Nacional de Ciencias Naturales (MNCN-CSIC); C/José Gutiérrez Abascal 2 28006 Madrid Spain
| | - Patrick S. Fitze
- Instituto Pirenaico de Ecología (IPE-CSIC); Avda Nuestra Señora de la Victoria 16 22700 Jaca Spain
- Department of Biodiversity and Evolutionary Biology; Museo Nacional de Ciencias Naturales (MNCN-CSIC); C/José Gutiérrez Abascal 2 28006 Madrid Spain
- Department of Ecology and Evolution; University of Lausanne; Biophore 1015 Lausanne Switzerland
- Fundación Araid; Edificio CEEI Aragón; C/María de Luna 11 50018 Zaragoza Spain
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42
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Turnell BR, Shaw KL. Polyandry and postcopulatory sexual selection in a wild population. Mol Ecol 2015; 24:6278-88. [PMID: 26577698 DOI: 10.1111/mec.13470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 11/28/2022]
Abstract
When females mate multiply, postcopulatory sexual selection can occur via sperm competition and cryptic female choice. Although postcopulatory selection has the potential to be a major force in driving evolution, few studies have estimated its strength in natural populations. Likewise, although polyandry is widespread across taxa and is the focus of a growing body of research, estimates of natural female mating rates are still limited in number. Microsatellites can be used to estimate the number of mates represented in females' sperm stores and the number of sires contributing to their offspring, enabling comparisons both of polyandry and of two components of postcopulatory selection: the proportion of males that mate but fail to sire offspring, and the degree of paternity skew among the males that do sire offspring. Here, we estimate the number of mates and sires among wild females in the Hawaiian swordtail cricket Laupala cerasina. We compare these estimates to the actual mating rates and paternity shares we observed in a semi-natural population. Our results show that postcopulatory sexual selection operates strongly in this species: wild females mated with an average minimum of 3.6 males but used the sperm from only 58% of them. Furthermore, among the males that did sire offspring, paternity was significantly skewed. These patterns were similar to those observed in the field enclosure, where females mated with an average of 5.7 males and used the sperm from 62% of their mates, with paternity significantly skewed among the sires.
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Affiliation(s)
- Biz R Turnell
- Neurobiology and Behavior, Cornell University, Ithaca, NY, 14853, USA
| | - Kerry L Shaw
- Neurobiology and Behavior, Cornell University, Ithaca, NY, 14853, USA
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43
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Scarponi V, Chowdhury D, Godin JGJ. Male Mating History Influences Female Mate Choice in the Trinidadian Guppy (Poecilia reticulata). Ethology 2015. [DOI: 10.1111/eth.12427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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44
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Evans GMV, Nowlan T, Shuker DM. Patterns of reproductive isolation within and between twoLygaeusspecies characterized by sexual conflicts over mating. Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12639] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Gethin M. V. Evans
- Institute of Evolutionary Biology; University of Edinburgh; West Mains Road Edinburgh EH9 3JT UK
| | - Toby Nowlan
- Institute of Evolutionary Biology; University of Edinburgh; West Mains Road Edinburgh EH9 3JT UK
| | - David M. Shuker
- School of Biology; University of St Andrews; Harold Mitchell Building St Andrews KY16 9TH UK
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45
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Garcia-Gonzalez F, Yasui Y, Evans JP. Mating portfolios: bet-hedging, sexual selection and female multiple mating. Proc Biol Sci 2015; 282:20141525. [PMID: 25411448 DOI: 10.1098/rspb.2014.1525] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Polyandry (female multiple mating) has profound evolutionary and ecological implications. Despite considerable work devoted to understanding why females mate multiply, we currently lack convincing empirical evidence to explain the adaptive value of polyandry. Here, we provide a direct test of the controversial idea that bet-hedging functions as a risk-spreading strategy that yields multi-generational fitness benefits to polyandrous females. Unfortunately, testing this hypothesis is far from trivial, and the empirical comparison of the across-generations fitness payoffs of a polyandrous (bet hedger) versus a monandrous (non-bet hedger) strategy has never been accomplished because of numerous experimental constraints presented by most 'model' species. In this study, we take advantage of the extraordinary tractability and versatility of a marine broadcast spawning invertebrate to overcome these challenges. We are able to simulate multi-generational (geometric mean) fitness among individual females assigned simultaneously to a polyandrous and monandrous mating strategy. Our approaches, which separate and account for the effects of sexual selection and pure bet-hedging scenarios, reveal that bet-hedging, in addition to sexual selection, can enhance evolutionary fitness in multiply mated females. In addition to offering a tractable experimental approach for addressing bet-hedging theory, our study provides key insights into the evolutionary ecology of sexual interactions.
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Affiliation(s)
- Francisco Garcia-Gonzalez
- Doñana Biological Station, Spanish Research Council CSIC, c/Americo Vespucio, s/n, Isla de la Cartuja 41092, Sevilla, Spain Centre for Evolutionary Biology, University of Western Australia, School of Animal Biology M092, Nedlands 6009, Western Australia
| | - Yukio Yasui
- Laboratory of Entomology, Faculty of Agriculture, Kagawa University, Ikenobe 2393, Miki-cho, Kita-gun, Kagawa 761-0795, Japan
| | - Jonathan P Evans
- Centre for Evolutionary Biology, University of Western Australia, School of Animal Biology M092, Nedlands 6009, Western Australia
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46
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Greenway EVG, Shuker DM. The repeatability of mating failure in a polyandrous bug. J Evol Biol 2015; 28:1578-82. [PMID: 26086205 PMCID: PMC4744990 DOI: 10.1111/jeb.12678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/18/2015] [Indexed: 12/02/2022]
Abstract
Mating failure, characterized by the lack of production of offspring following copulation, is relatively common across taxa yet is little understood. It is unclear whether mating failures are stochastic occurrences between incompatible mating partners or represent a persistent, meaningful phenotype on the part of one or other sex. Here we test this in the seed bug Lygaeus simulans, by sequentially mating families of males with randomly allocated unrelated females and calculating the repeatability of mating outcome for each individual male and family. Mating outcome is significantly repeatable within individual males but not across full‐sib brothers. We conclude that mating failure represents a consistent male‐associated phenotype with low heritability in this species, affected by as yet undetermined environmental influences on males.
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Affiliation(s)
- E V Ginny Greenway
- School of Biology, University of St Andrews, St Andrews, Fife, KY16 9TH, UK
| | - D M Shuker
- School of Biology, University of St Andrews, St Andrews, Fife, KY16 9TH, UK
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47
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Burdfield-Steel ER, Auty S, Shuker DM. Do the benefits of polyandry scale with outbreeding? Behav Ecol 2015; 26:1423-1431. [PMID: 26379413 PMCID: PMC4568444 DOI: 10.1093/beheco/arv103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 06/08/2015] [Accepted: 06/13/2015] [Indexed: 11/13/2022] Open
Abstract
There have been many potential explanations put forward as to why polyandry often persists despite the multiple costs it can inflict on females. One such explanation is avoidance of costs associated with mating with genetically incompatible males. Genetic incompatibility can be thought of as a spectrum from individuals that are genetically too similar (inbreeding) to those that are too dissimilar (outbreeding or hybridization). Here we look for evidence that the level of outbreeding influences the benefits of polyandry in the seed bug Lygaeus equestris. Our system allows us to test for benefits of polyandry at levels of genetic similarity ranging from full siblings to heterospecifics, both in terms of egg production and hatching success. We found that while outbreeding level appeared to have no effect on fitness for intraspecific matings, and polyandry did not appear to result in any increase in fertility or fecundity, hybridization with a closely related species, Lygaeus simulans, carried considerable fitness costs. However, these costs could be rescued with a single mating to a conspecific. Thus, polyandry may be beneficial in populations that co-occur with closely related species and where there is reproductive interference. However, within-species genetic incompatibility is unlikely to be the driving force behind polyandry in this species. Furthermore, the mechanism underlying this rescue of fertility remains unclear as manipulation of male cuticular hydrocarbon profile, a possible mechanism by which females can assess male identity, had no effect on female offspring production.
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Affiliation(s)
- Emily R Burdfield-Steel
- School of Biology, University of St Andrews , Harold Mitchell Building , St Andrews, Fife KY16 9TH , UK and ; Department of Biological and Environmental Science, Centre of Excellence in Biological Interactions, University of Jyväskylä , PO Box 35, Jyväskylä 40014 , Finland
| | - Sam Auty
- School of Biology, University of St Andrews , Harold Mitchell Building , St Andrews, Fife KY16 9TH , UK and
| | - David M Shuker
- School of Biology, University of St Andrews , Harold Mitchell Building , St Andrews, Fife KY16 9TH , UK and
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48
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49
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Kalinka AT. How did viviparity originate and evolve? Of conflict, co-option, and cryptic choice. Bioessays 2015; 37:721-31. [PMID: 25904118 DOI: 10.1002/bies.201400200] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
I propose that the underlying adaptation enabling the reproductive strategy of birthing live young (viviparity) is retraction of the site of fertilization within the female reproductive tract, and that this evolved as a means of postcopulatory sexual selection. There are three conspicuous aspects associated with viviparity: (i) internal development is a complex trait often accompanied by a suite of secondary adaptations, yet it is unclear how the intermediate state of this trait - egg retention - could have evolved; (ii) viviparity often results in a reduction in fecundity; (iii) viviparity has evolved independently many times across a diverse array of animal groups. Focusing on the Diptera (true flies), I provide explanations for these observations. I further propose that fecundity is not traded-off to enable potential benefits of viviparity, but rather that loss of fecundity is directly selected and egg retention is an indirect consequence - a model that provides a unifying common basis for the ubiquity of viviparity.
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Affiliation(s)
- Alex T Kalinka
- Institute of Population genetics, Vetmeduni, Vienna, Austria
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50
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Wilson CJ, Tomkins JL. Female Callosobruchus maculatus can maximize long-term fitness through polyandry. Behav Ecol 2014. [DOI: 10.1093/beheco/aru218] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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