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Ujszegi J, Ujhegyi N, Balogh E, Mikó Z, Kásler A, Hettyey A, Bókony V. No sex-dependent mortality in an amphibian upon infection with the chytrid fungus, Batrachochytrium dendrobatidis. Ecol Evol 2024; 14:e70219. [PMID: 39219568 PMCID: PMC11362217 DOI: 10.1002/ece3.70219] [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: 03/21/2024] [Revised: 08/07/2024] [Accepted: 08/09/2024] [Indexed: 09/04/2024] Open
Abstract
One of the major factors driving the currently ongoing biodiversity crisis is the anthropogenic spread of infectious diseases. Diseases can have conspicuous consequences, such as mass mortality events, but may also exert covert but similarly severe effects, such as sex ratio distortion via sex-biased mortality. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is among the most important threats to amphibian biodiversity. Yet, whether Bd infection can skew sex ratios in amphibians is currently unknown, although such a hidden effect may cause the already dwindling amphibian populations to collapse. To investigate this possibility, we collected common toad (Bufo bufo) tadpoles from a natural habitat in Hungary and continuously treated them until metamorphosis with sterile Bd culture medium (control), or a liquid culture of a Hungarian or a Spanish Bd isolate. Bd prevalence was high in animals that died during the experiment but was almost zero in individuals that survived until the end of the experiment. Both Bd treatments significantly reduced survival after metamorphosis, but we did not observe sex-dependent mortality in either treatment. However, a small number of genotypically female individuals developed male phenotype (testes) in the Spanish Bd isolate treatment. Therefore, future research is needed to ascertain if larval Bd infection can affect sex ratio in common toads through female-to-male sex reversal.
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Affiliation(s)
- János Ujszegi
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
- Department of Systematic Zoology and EcologyELTE Eötvös Loránd UniversityBudapestHungary
| | - Nikolett Ujhegyi
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
| | - Emese Balogh
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
- Department of ZoologyUniversity of Veterinary Medicine BudapestBudapestHungary
| | - Zsanett Mikó
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
| | - Andrea Kásler
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
- Department of Systematic Zoology and EcologyELTE Eötvös Loránd UniversityBudapestHungary
- Doctoral School of Biology, Institute of BiologyELTE Eötvös Loránd UniversityBudapestHungary
| | - Attila Hettyey
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
- Department of Systematic Zoology and EcologyELTE Eötvös Loránd UniversityBudapestHungary
| | - Veronika Bókony
- Department of Evolutionary Ecology, HUN‐REN Centre for Agricultural ResearchPlant Protection InstituteBudapestHungary
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2
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Kappeler PM, Fichtel C. Independent fitness consequences of group size variation in Verreaux's sifakas. Commun Biol 2024; 7:816. [PMID: 38965399 PMCID: PMC11224245 DOI: 10.1038/s42003-024-06484-z] [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] [Received: 02/12/2024] [Accepted: 06/21/2024] [Indexed: 07/06/2024] Open
Abstract
The costs and benefits of group living are also reflected in intraspecific variation in group size. Yet, little is known about general patterns of fitness consequences of this variation. We use demographic records collected over 25 years to determine how survival and reproductive success vary with group size in a Malagasy primate. We show that female reproductive rates of Verreaux's sifakas (Propithecus verreauxi) are not affected by total group size, but that they are supressed by the number of co-resident females, whereas mortality rates are significantly higher in larger groups. Neither annual rainfall nor the adult sex ratio have significant effects on birth and death rates. Hence, these sifakas enjoy the greatest net fitness benefits at small, and not the predicted intermediate group sizes. Thus, independent fitness proxies can vary independently as a function of group size as well as other factors, leading to deviations from optimal intermediate group sizes.
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Affiliation(s)
- Peter M Kappeler
- Behavioral Ecology & Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077, Göttingen, Germany.
- Department of Sociobiology/Anthropology, Johann-Friedrich-Blumenbach Institute of Zoology and Anthropology, University Göttingen, Kellnerweg 6, 37077, Göttingen, Germany.
| | - Claudia Fichtel
- Behavioral Ecology & Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077, Göttingen, Germany
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3
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Beissinger SR, Berg KS. Eviction-driven infanticide and sexually selected adoption and infanticide in a neotropical parrot. Proc Natl Acad Sci U S A 2024; 121:e2317305121. [PMID: 38709919 PMCID: PMC11098109 DOI: 10.1073/pnas.2317305121] [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: 10/06/2023] [Accepted: 04/04/2024] [Indexed: 05/08/2024] Open
Abstract
Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually selected infanticide is well known, evidence for sexually selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 y in green-rumped parrotlets (Forpus passerinus) in Venezuela. Parrotlets are monogamous with long-term pair bonds, exhibit a strongly male-biased adult sex ratio, and nest in cavities that are in short supply, creating intense competition for nest sites and mates. Infanticide attacks occurred at 256 nests in two distinct contexts: 1) Attacks were primarily committed by nonbreeding pairs (69%) attempting to evict parents from the cavity. Infanticide attacks per nest were positively correlated with population size and evicting pairs never adopted abandoned offspring. Competition for limited nest sites was a primary cause of eviction-driven infanticide, and 2) attacks occurred less frequently at nests where one mate died (31%), was perpetrated primarily by stepparents of both sexes, and was independent of population size. Thus, within a single species and mating system, infanticide occurred in multiple contexts due to multiple drivers. Nevertheless, 48% of stepparents of both sexes adopted offspring, and another 23% of stepfathers exhibited both infanticide and long-term care. Stepfathers were often young males who subsequently nested with widows, reaching earlier ages of first breeding than competitors and demonstrating sexually selected adoption. Adoption and infanticide conferred similar fitness benefits to stepfathers and appeared to be equivalent strategies driven by limited breeding opportunities, male-biased sex ratios, and long-term monogamy.
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Affiliation(s)
- Steven R. Beissinger
- Department of Environmental Science, Policy & Management, University of California, Berkeley, CA94720
- Museum of Vertebrate Zoology, University of California, Berkeley, CA94720
| | - Karl S. Berg
- School of Integrative Biological and Chemical Sciences, University of Texas Rio Grande Valley, Brownsville, TX78520
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4
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Borries C, Koenig A. Female-biased birth sex ratio in a female dispersal primate suggests local resource competition. Biol Lett 2024; 20:20240002. [PMID: 38689558 PMCID: PMC11061642 DOI: 10.1098/rsbl.2024.0002] [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: 01/02/2024] [Revised: 02/12/2024] [Accepted: 02/27/2024] [Indexed: 05/02/2024] Open
Abstract
Group living may entail local resource competition (LRC) which can be reduced if the birth sex ratio (BSR) is biased towards members of the dispersing sex who leave the group and no longer compete locally with kin. In primates, the predicted relationship between dispersal and BSR is generally supported although data for female dispersal species are rare and primarily available from captivity. Here, we present BSR data for Phayre's leaf monkeys (Trachypithecus phayrei crepusculus) at the Phu Khieo Wildlife Sanctuary, Thailand (N = 104). In this population, nearly all natal females dispersed, while natal males stayed or formed new groups nearby. The slower reproductive rate in larger groups suggests that food can be a limiting resource. In accordance with LRC, significantly more females than males were born (BSR 0.404 males/all births) thus reducing future competition with kin. This bias was similar in 2-year-olds (no sex-differential mortality). It became stronger in adults, supporting our impression of particularly fierce competition among males. To better evaluate the importance of BSR, more studies should report sex ratios throughout the life span, and more data for female dispersal primates need to be collected, ideally for multiple groups of different sizes and for several years.
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Affiliation(s)
- Carola Borries
- Department of Anthropology and Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Andreas Koenig
- Department of Anthropology and Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY, USA
- Graduate Program in Ecology and Evolution, Stony Brook University, Stony Brook, NY, USA
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Bókony V, Kalina C, Ujhegyi N, Mikó Z, Lefler KK, Vili N, Gál Z, Gabor CR, Hoffmann OI. Does stress make males? An experiment on the role of glucocorticoids in anuran sex reversal. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:172-181. [PMID: 38155497 DOI: 10.1002/jez.2772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/30/2023]
Abstract
Environmentally sensitive sex determination may help organisms adapt to environmental change but also makes them vulnerable to anthropogenic stressors, with diverse consequences for population dynamics and evolution. The mechanisms translating environmental stimuli to sex are controversial: although several fish experiments supported the mediator role of glucocorticoid hormones, results on some reptiles challenged it. We tested this hypothesis in amphibians by investigating the effect of corticosterone on sex determination in agile frogs (Rana dalmatina). This species is liable to environmental sex reversal whereby genetic females develop into phenotypic males. After exposing tadpoles during sex determination to waterborne corticosterone, the proportion of genetic females with testes or ovotestes increased from 11% to up to 32% at 3 out of 4 concentrations. These differences were not statistically significant except for the group treated with 10 nM corticosterone, and there was no monotonous dose-effect relationship. These findings suggest that corticosterone is unlikely to mediate sex reversal in frogs. Unexpectedly, animals originating from urban habitats had higher sex-reversal and corticosterone-release rates, reduced body mass and development speed, and lower survival compared to individuals collected from woodland habitats. Thus, anthropogenic environments may affect both sex and fitness, and the underlying mechanisms may vary across ectothermic vertebrates.
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Affiliation(s)
- Veronika Bókony
- Department of Evolutionary Ecology, Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest, Hungary
- Department of Zoology, University of Veterinary Medicine Budapest, Budapest, Hungary
| | - Csenge Kalina
- Department of Zoology, University of Veterinary Medicine Budapest, Budapest, Hungary
| | - Nikolett Ujhegyi
- Department of Evolutionary Ecology, Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest, Hungary
| | - Zsanett Mikó
- Department of Evolutionary Ecology, Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest, Hungary
| | - Kinga Katalin Lefler
- Department of Aquaculture, Institute of Agricultural and Environmental Safety, Hungarian University of Agriculture and Life Science, Gödöllő, Hungary
| | - Nóra Vili
- Department of Zoology, University of Veterinary Medicine Budapest, Budapest, Hungary
| | - Zoltán Gál
- Department of Animal Biotechnology, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Science, Gödöllő, Hungary
| | - Caitlin R Gabor
- Department of Biology, Texas State University, San Marcos, Texas, USA
| | - Orsolya Ivett Hoffmann
- Department of Animal Biotechnology, Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Science, Gödöllő, Hungary
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6
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Krietsch J, Valcu M, Cragnolini M, Forstmeier W, Kempenaers B. Mutual mate guarding with limited sexual conflict in a sex-role-reversed shorebird. Behav Ecol 2024; 35:arad084. [PMID: 38193015 PMCID: PMC10773304 DOI: 10.1093/beheco/arad084] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 08/22/2023] [Accepted: 09/18/2023] [Indexed: 01/10/2024] Open
Abstract
Mate guarding is typically considered a male strategy to protect paternity. However, under some circumstances, females might also benefit from guarding their mate. Female mate guarding might be particularly important in socially polyandrous species in which females compete for access to care-giving males. Because males also benefit from being near their partner to avoid paternity loss, pair members may have a mutual interest in mate guarding in polyandrous species. We studied the time spent together and movements that lead to separation, as behavioral measures of mate guarding, in the classically polyandrous red phalarope (Phalaropus fulicarius). We equipped 64 breeding pairs with miniaturized telemetry loggers with GPS to assess variation in mate-guarding intensity in relation to breeding phenology and season, nest attendance, and the occurrence of extrapair paternity. We show that red phalarope pairs were almost continuously together in the days before clutch initiation with no sex bias in separation movements, indicating mutual contribution to mate guarding. Our results suggest that in red phalaropes, both pair members guard their mate, with limited sexual conflict arising through biases in the operational sex ratio and a trade-off with male nest attendance. We found no clear relationship between mate-guarding intensity and the occurrence of extrapair paternity. In this non-territorial socially polyandrous species, mutual mate guarding might be the process underlying the evolution of a brief but strong social pair bond, with no other purpose than producing a clutch for a care-giving male.
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Affiliation(s)
- Johannes Krietsch
- Department of Ornithology, Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str., 82319 Seewiesen, Germany
| | - Mihai Valcu
- Department of Ornithology, Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str., 82319 Seewiesen, Germany
| | - Margherita Cragnolini
- Department of Ornithology, Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str., 82319 Seewiesen, Germany
| | - Wolfgang Forstmeier
- Department of Ornithology, Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str., 82319 Seewiesen, Germany
| | - Bart Kempenaers
- Department of Ornithology, Max Planck Institute for Biological Intelligence, Eberhard Gwinner Str., 82319 Seewiesen, Germany
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7
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McCool WC, Codding BF. US homicide rates increase when resources are scarce and unequally distributed. EVOLUTIONARY HUMAN SCIENCES 2023; 6:e3. [PMID: 38516371 PMCID: PMC10955375 DOI: 10.1017/ehs.2023.31] [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: 05/26/2023] [Revised: 10/13/2023] [Accepted: 11/15/2023] [Indexed: 03/23/2024] Open
Abstract
As homicide rates spike across the United States, researchers nominate diverse causes such as temperature, city greenness, structural racism, inequality, poverty and more. While variation in homicide rates clearly results from multiple causes, many correlation studies lack the systematic theory needed to identify the underlying factors that structure individual motivations. Building on pioneering work in evolutionary human sciences, we propose that when resources are unequally distributed, individuals may have incentives to undertake high-risk activities, including lethal violence, in order to secure material and social capital. Here we evaluate this theory by analysing federal data on homicide rates, poverty and income inequality across all 50 US states for the years 1990, 2000 and 2005-2020. Supporting predictions derived from evolutionary social sciences, we find that the interaction of poverty (scarcity) and inequality (unequal distribution) best explains variation in US homicide rates. Results suggest that the increase in homicide rates during the height of the COVID-19 pandemic are driven in part by these same underlying causes that structure homicide rates across the US over the last 30 years. We suggest that these results provide compelling evidence to expand strategies for reducing homicide rates by dismantling structures that generate and concentrate sustained poverty and economic inequality.
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Affiliation(s)
- Weston C. McCool
- Department of Anthropology, University of Utah, Salt Lake City, UT 84102, USA
- Society, Water, and Climate Interdisciplinary Research Group, University of Utah, Salt Lake City, UT 84102, USA
| | - Brian F. Codding
- Department of Anthropology, University of Utah, Salt Lake City, UT 84102, USA
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8
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Székely T. Evolution of reproductive strategies: sex roles, sex ratios and phylogenies. Biol Futur 2023; 74:351-357. [PMID: 37723361 DOI: 10.1007/s42977-023-00177-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 08/22/2023] [Indexed: 09/20/2023]
Abstract
Behavioural variations associated with breeding-termed reproductive strategies-are some of the striking behaviours that have occupied naturalists for 1000s of years. How an animal seeks, competes for and/or chooses a mate? Do they breed with a single partner, or do they change partners between breeding events? How and when do they look after their young? Behavioural biologists, ecologists and evolutionary biologists have investigated these questions using quantitative methods since 1970s. In Debrecen, with the support and mentoring of Prof Zoltán Varga, we are investigating the causes and implications of reproductive strategies since 1988. This article reviews some of the core ideas in reproductive strategies research and explains the influence of Prof Varga on the development of these ideas. My main thesis here is that both integrative thinking and adopting a multi-pronged research approach using an explicit phylogenetic framework-both of these have been spearheaded by Prof Varga throughout his lifetime-can reveal novel aspects of reproductive strategies. Importantly, some of these academic insights have direct implications for preserving species and their habitats in the wild, and thus benefit biodiversity conservation.
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Affiliation(s)
- Tamás Székely
- Milner Centre for Evolution, University of Bath, Bath, BA2 7AY, UK.
- ELKH - DE Reproductive strategies Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Egyetem Tér 1, Debrecen, 4032, Hungary.
- Debrecen Biodiversity Centre, University of Debrecen, Debrecen, 4032, Hungary.
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9
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Dorken ME. Causes and consequences of sex ratio variation in plants. A commentary on: 'Life history characteristics and historical factors are important to explain regional variation in reproductive traits and genetic diversity in perennial mosses'. ANNALS OF BOTANY 2023; 132:viii-x. [PMID: 37793136 PMCID: PMC10550265 DOI: 10.1093/aob/mcad092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
This article comments on:
Irene Bisang, Johan Ehrlén, and Lars Hedenäs. Life-history characteristics and historical factors are important to explain regional variation in reproductive traits and genetic diversity in perennial mosses, Annals of Botany, Volume 132, Issue 1, 1 July 2023, Pages 29–42, https://doi.org/10.1093/aob/mcad045
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Affiliation(s)
- Marcel E Dorken
- Department of Biology, Trent University, 1600 West Bank Drive, K9L 0G2, Peterborough, Canada
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10
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Araujo G, Moura RR. Beyond classical theories: An integrative mathematical model of mating dynamics and parental care. J Evol Biol 2023; 36:1411-1427. [PMID: 37691454 DOI: 10.1111/jeb.14210] [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] [Received: 04/24/2022] [Revised: 06/29/2023] [Accepted: 07/11/2023] [Indexed: 09/12/2023]
Abstract
Classical theories, such as Bateman's principle and Trivers' parental investment theory, attempted to explain the coevolution of sexual selection and parental care through simple verbal arguments. Since then, quantitative models have demonstrated that it is rarely that simple because many non-intuitive structures and non-linear relationships are actually at play. In this study, we propose a new standard for models of mating dynamics and parental care, emphasizing the clarity and use of mathematical and probabilistic arguments, the meaning of consistency conditions, and the key role of spatial densities and the law of mass action. We used adaptive dynamics to calculate the evolutionary trajectory of the total care duration. Our results clearly show how the outcomes of parental care evolution can be diverse, depending on the quantitative balance between a set of dynamical forces arising from relevant differences and conditions in the male and female populations. The intensity of sexual selection, synergy of care, care quality, and relative mortality rates during mating interactions and caring activities act as forces driving evolutionary transitions between uniparental and biparental care. Sexual selection reduces the care duration of the selected sex, uniparental care evolves in the sex that offers the higher care quality, higher mortality during mating interactions of one sex leads to more care by that sex, and higher mortality during caring activities of one sex favours the evolution of uniparental care in the other sex. Both synergy and higher overall mortality during mating interactions can stabilize biparental care when sexual selection reduces the care duration of the selected sex. We discuss how the interaction between these forces influences the evolution of care patterns, and how sex ratios can vary and be interpreted in these contexts. We also propose new directions for future developments of our integrative model, creating new comparable analyses that share the same underlying assumptions and dynamical frameworks.
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Affiliation(s)
- Gui Araujo
- Faculty of Science and Engineering, Department of Biosciences, Swansea University, Wales, UK
- Departamento de Ciâncias Agrárias e Naturais, Núcleo de Extensão e Pesquisa em Ecologia e Evolução (NEPEE), Universidade do Estado de Minas Gerais, Ituiutaba, Brazil
| | - Rafael Rios Moura
- Departamento de Ciâncias Agrárias e Naturais, Núcleo de Extensão e Pesquisa em Ecologia e Evolução (NEPEE), Universidade do Estado de Minas Gerais, Ituiutaba, Brazil
- Pós-graduação em Ecologia, Conservação e Biodiversidade, Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Brazil
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11
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Du S, Murray RL. Road salt pollution alters sex ratios in emerging mosquito populations. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 334:122203. [PMID: 37453680 DOI: 10.1016/j.envpol.2023.122203] [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: 05/12/2023] [Revised: 06/27/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
De-icing road salt is a persistent emerging pollutant in temperate freshwater systems, where winter salting is necessary for road and pedestrian safety. Experts argue that road salts may increase salt-tolerant mosquito populations and, potentially, disease transmission in urban areas. Only adult females consume bloodmeals and may carry zoonotic diseases. While there are some species with naturally occurring male-biased sex ratios, it is unclear whether road salt differentially affects male and female mosquitoes to alter sex ratios. We hypothesized that road salts would masculinize emergence sex ratios and decrease female success because females may face higher exposure to stressors during their lengthy juvenile development compared to males. We measured mosquito emergence sex ratios of control (0 g/L added salt) and salt (4.5 g/L added salt) mesocosms in southern Ontario, Canada across the West Nile Virus season (May to October). We found female-biased sex ratios (i.e., <50% male frequency) in both 0 and 4.5 g/L. While mosquito abundance was significantly higher in 4.5 g/L compared to 0 g/L, road salt significantly increased the proportion of emerging males from 32.8% to 40.8% (Negative Binomial Model; Estimate ± SE = 0.283 ± 0.108; P = 0.009); mosquitoes shift their sex ratios from female-biased towards parity (50:50) in response to salt. Our study illustrates the need to evaluate sex-specific abundance in pollution-related mosquito population studies. By showing a shift toward more male mosquitoes emerging in high salinity compared to control treatments, our results suggest that road salts may have the potential to decrease female mosquito success and indirectly reduce disease transmission in cities.
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Affiliation(s)
- Sherry Du
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada; Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, ON, M5S 3B2, Canada; Centre for Urban Environments, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada.
| | - Rosalind L Murray
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada; Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St, Toronto, ON, M5S 3B2, Canada; Centre for Urban Environments, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga, ON, L5L 1C6, Canada
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12
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Andersson L, Jalovaara M, Saarela J, Uggla C. A matter of time: Bateman's principles and mating success as count and duration across social strata in contemporary Finland. Proc Biol Sci 2023; 290:20231061. [PMID: 37434521 PMCID: PMC10336387 DOI: 10.1098/rspb.2023.1061] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 06/19/2023] [Indexed: 07/13/2023] Open
Abstract
Bateman's principles heavily influence the understanding of human reproductive behaviour. Yet, few rigorous studies on Bateman's principles in contemporary industrialized populations exist. Most studies use small samples, exclude non-marital unions, and disregard recent insights on within-population heterogeneity in mating strategies. We assess mating success and reproductive success using population-wide Finnish register data on marital and non-marital cohabitations and fertility. We examine variability across social strata in the Bateman principles and analyse the mate count, the cumulated duration with a mate, and the association with reproductive success. Results support Bateman's first and second principles. Regarding Bateman's third principle, the number of mates is more positively associated with reproductive success for men than women, but this association is driven by ever having a mate. Having more than one mate is on average associated with lower reproductive success. However, for men in the lowest income quartile, having more than one mate positively predicts reproductive success. Longer union duration is associated with higher reproductive success, and more so for men. We note that sex differences in the relationship between mating success and reproductive success differ by social strata, and argue that mate duration may be an important component of mating success alongside mate count.
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Affiliation(s)
- Linus Andersson
- Department of Social Research, University of Turku, Turku, Varsinais-Suomi, 20014 Finland
- The Swedish Institute for Social Research, Stockholm University, Stockholm, 10691, Sweden
| | - Marika Jalovaara
- Department of Social Research, University of Turku, Turku, Varsinais-Suomi, 20014 Finland
| | - Jan Saarela
- Åbo Akademi, Abo, Varsinais-Suomi, 20500 Finland
| | - Caroline Uggla
- Stockholm University Demography Unit (SUDA), Department of Sociology, Stockholm University, Stockholm, 106 91, Sweden
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