1
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Renoirt M, Angelier F, Cheron M, Brischoux F. What are the contributions of maternal and paternal traits to fecundity and offspring development? A case study in an amphibian species, the spined toad Bufo spinosus. Curr Zool 2023; 69:527-534. [PMID: 37637310 PMCID: PMC10449425 DOI: 10.1093/cz/zoac072] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/25/2022] [Indexed: 08/29/2023] Open
Abstract
Assessing the determinants of reproductive success is critical but often complicated because of complex interactions between parental traits and environmental conditions occurring during several stages of a reproductive event. Here, we used a simplified ecological situation-an amphibian species lacking post-oviposition parental care-and a laboratory approach to investigate the relationships between parental (both maternal and paternal) phenotypes (body size and condition) and reproductive success (fecundity, egg size, embryonic and larval duration, larval and metamorphic morphology). We found significant effects of maternal phenotype on fecundity, hatching success, and tadpole size, as well as on the duration of larval development. Interestingly, and more surprisingly, we also found a potential contribution of the paternal phenotype occurring during early (embryonic development duration) offspring development. Although our study focused on life-history traits such as body size and development duration, additional mechanisms involving physiological costs of development may well mediate the relationships between parental phenotypes and offspring development. Future studies are required to decipher the mechanisms underlying our findings in order to clarify the mechanistic basis of the links between parental phenotypes and offspring development.
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Affiliation(s)
- Matthias Renoirt
- Centre d’Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
| | - Frédéric Angelier
- Centre d’Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
| | - Marion Cheron
- Centre d’Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
| | - François Brischoux
- Centre d’Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
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2
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James A, Hann A, Holland EP. Brood size in an uncertain world. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221362. [PMID: 37351496 PMCID: PMC10282570 DOI: 10.1098/rsos.221362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
Reproduction in an uncertain world is fraught. The consequences of investing in too many offspring in a resource poor season can be disastrous but so too is missing the opportunity of a resource rich year. We consider a simple population and individual growth model and use Lyapunov exponents to find analytical results for the optimum brood size under stochastic environmental conditions. We show that if the environment shows dramatic changes between breeding seasons choosing a smaller brood size is more likely to be successful but the best strategy is to synchronize your reproduction to the food availability. Finally, we show that if the cost of having offspring is high it can be better to live in a highly varying world with a plastic strategy that synchronizes to the environment than to live in a deterministic world with a constant strategy, a finding with implications for invasive species and climate change.
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Affiliation(s)
- Alex James
- School of Maths and Stats, University of Canterbury, Christchurch, New Zealand
| | - Alexander Hann
- School of Maths and Stats, University of Canterbury, Christchurch, New Zealand
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3
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Aguilar P, Dag B, Carazo P, Sultanova Z. Sex-specific paternal age effects on offspring quality in Drosophila melanogaster. J Evol Biol 2023; 36:720-729. [PMID: 36946550 DOI: 10.1111/jeb.14167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 03/23/2023]
Abstract
Advanced paternal age has been repeatedly shown to modulate offspring quality via male- and/or female-driven processes, and there are theoretical reasons to expect that some of these effects can be sex-specific. For example, sex allocation theory predicts that, when mated with low-condition males, mothers should invest more in their daughters compared to their sons. This is because male fitness is generally more condition-dependent and more variable than female fitness, which makes it less risky to invest in female offspring. Here, we explore whether paternal age can affect the quality and quantity of offspring in a sex-specific way using Drosophila melanogaster as a model organism. In order to understand the contribution of male-driven processes on paternal age effects, we also measured the seminal vesicle size of young and older males and explored its relationship with reproductive success and offspring quality. Older males had lower competitive reproductive success, as expected, but there was no difference between the offspring sex ratio of young and older males. However, we found that paternal age caused an increase in offspring quality (i.e., offspring weight), and that this increase was more marked in daughters than sons. We discuss different male- and female-driven processes that may explain such sex-specific paternal age effects.
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Affiliation(s)
- Prem Aguilar
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Porto, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Berfin Dag
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Bogazici University, Istanbul, Turkey
| | - Pau Carazo
- Cavanilles Institute of Biodiversity and Evolutionary Biology, Valencia, Spain
| | - Zahida Sultanova
- School of Biological Sciences, University of East Anglia, Norwich, UK
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4
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The breeding biology of erect-crested penguins, Eudyptes sclateri: Hormones, behavior, obligate brood reduction and conservation. PLoS One 2022; 17:e0275106. [PMID: 36223344 PMCID: PMC9555622 DOI: 10.1371/journal.pone.0275106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/11/2022] [Indexed: 11/06/2022] Open
Abstract
Erect-crested penguins are the least studied of all penguins. They breed on two isolated subantarctic island groups, the Antipodes and Bounty Islands. Sporadic nest counts indicate a dramatic decline in numbers of erect-crested penguins over the last 50 years. Here we present data from a study undertaken in 1998 on the breeding biology, behavior and hormones of erect-crested penguins. It represents, even today, by far the most detailed data available on this species. The penguins exhibited extreme reversed egg-size dimorphism, whereby the first-laid A-egg was much smaller than the second-laid B-egg. A-eggs were lost before (42.3%) or on (37.8%) the day the B-egg was laid, and none survived more than 7 days after that. The penguins were in a low state of reproductive readiness, as evidenced by low levels of copulation, fighting, and testosterone in males during the courtship/laying period when, curiously, plasma levels of testosterone were at least as high in females. The laying interval (5.4 days) is the longest recorded for any penguin species, and incubation was highly variable until clutch completion. Most nests (91.2%) contained no nesting material and eggs were laid directly onto the ground. A-eggs were lost mainly by rolling out of the nest. However, even when prevented from doing so by an experimental manipulation, A-eggs survived no longer than those in control nests. Testosterone levels in males increased after clutch completion, when they remained in attendance at the nest for up to 13 days, despite females assuming most of the incubation duties. The bills of males were significantly larger than those of females and probably help with guarding the nest. We discuss explanations for obligate brood reduction in crested penguins and the options for conservation in light of our census results, which indicate that this enigmatic penguin species could be in trouble.
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5
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Shinde S, Patwardhan A, Watve M. The ratio versus difference optimization and its implications for optimality theory. Evolution 2022; 76:2272-2280. [PMID: 36029469 DOI: 10.1111/evo.14605] [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: 03/05/2021] [Revised: 07/29/2022] [Accepted: 08/12/2022] [Indexed: 01/22/2023]
Abstract
Among the classical models of optimization, some models maximize the ratio of returns to investment and others maximize the difference between returns and investment. However, an understanding of under what conditions the ratio or the difference approaches are appropriate is still fragmentary. Under specific contexts, it has been stated that when the investable amount, but not the opportunity for investment, is perceived to be limiting, a ratio optimum is appropriate, whereas a difference optimum is appropriate when the opportunity for investment, but not the investable amount, is perceived to be limiting. The question is important because the strategies indicated by ratio optimum can be substantially different than the ones suggested by difference optimum. We make a general case here to examine and expand this principle and apply it to many evolutionary ecological problems including parental investment, offspring quality-quantity trade-off, nectar production, pollinator behavior viral burst size, and intracellular protein handling. We show that the ratio-difference distinction in optimization models resolves many long-standing debates and conundrums in evolution and behavior.
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Affiliation(s)
- Sonali Shinde
- Annasaheb Kulkarni Department of Biodiversity, Abasaheb Garware College, Pune, 411004, India
| | - Ankur Patwardhan
- Annasaheb Kulkarni Department of Biodiversity, Abasaheb Garware College, Pune, 411004, India
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6
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Schlippe Justicia L, Fouilloux CA, Rojas B. Poison frog social behaviour under global change: potential impacts and future challenges. Acta Ethol 2022. [DOI: 10.1007/s10211-022-00400-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractThe current and cascading effects of global change challenges the interactions both between animal individuals (i.e. social and sexual behaviour) and the environment they inhabit. Amphibians are an ecologically diverse class with a wide range of social and sexual behaviours, making them a compelling model to understand the potential adaptations of animals faced with the effects of human-induced rapid environmental changes (HIREC). Poison frogs (Dendrobatoidea) are a particularly interesting system, as they display diverse social behaviours that are shaped by conspecific and environmental interactions, thus offering a tractable system to investigate how closely related species may respond to the impacts of HIREC. Here, we discuss the potential impacts of global change on poison frog behaviour, and the future challenges this group may face in response to such change. We pay special attention to parental care and territoriality, which are emblematic of this clade, and consider how different species may flexibly respond and adapt to increasingly frequent and diverse anthropogenic stress. More specifically, we hypothesise that some parents may increase care (i.e. clutch attendance and distance travelled for tadpole transport) in HIREC scenarios and that species with more generalist oviposition and tadpole deposition behaviours may fare more positively than their less flexible counterparts; we predict that the latter may either face increased competition for resources limited by HIREC or will be forced to adapt and expand their natural preferences. Likewise, we hypothesise that human-driven habitat alteration will disrupt the acoustic and visual communication systems due to increased noise pollution and/or changes in the surrounding light environment. We highlight the need for more empirical research combining behavioural ecology and conservation to better predict species’ vulnerability to global change and efficiently focus conservation efforts.
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7
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Barreaux AMG, Higginson AD, Bonsall MB, English S. Incorporating effects of age on energy dynamics predicts nonlinear maternal allocation patterns in iteroparous animals. Proc Biol Sci 2022; 289:20211884. [PMID: 35168397 PMCID: PMC8848239 DOI: 10.1098/rspb.2021.1884] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 01/18/2022] [Indexed: 12/12/2022] Open
Abstract
Iteroparous parents face a trade-off between allocating current resources to reproduction versus maximizing survival to produce further offspring. Parental allocation varies across age and follows a hump-shaped pattern across diverse taxa, including mammals, birds and invertebrates. This nonlinear allocation pattern lacks a general theoretical explanation, potentially because most studies focus on offspring number rather than quality and do not incorporate uncertainty or age-dependence in energy intake or costs. Here, we develop a life-history model of maternal allocation in iteroparous animals. We identify the optimal allocation strategy in response to stochasticity when energetic costs, feeding success, energy intake and environmentally driven mortality risk are age-dependent. As a case study, we use tsetse, a viviparous insect that produces one offspring per reproductive attempt and relies on an uncertain food supply of vertebrate blood. Diverse scenarios generate a hump-shaped allocation when energetic costs and energy intake increase with age and also when energy intake decreases and energetic costs increase or decrease. Feeding success and environmentally driven mortality risk have little influence on age-dependence in allocation. We conclude that ubiquitous evidence for age-dependence in these influential traits can explain the prevalence of nonlinear maternal allocation across diverse taxonomic groups.
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Affiliation(s)
- Antoine M. G. Barreaux
- School of Biological sciences, University of Bristol, Bristol BS8 1TQ, UK
- CIRAD, UMR INTERTRYP, F-34398 Montpellier, France
- INTERTRYP, Univ Montpellier, CIRAD, IRD, 34000 Montpellier, France
| | - Andrew D. Higginson
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| | - Michael B. Bonsall
- Department of Zoology, Mathematical Ecology Research Group, University of Oxford, Oxford OX1 3PS, UK
- St Peters College, Oxford OX1 2DL, UK
| | - Sinead English
- School of Biological sciences, University of Bristol, Bristol BS8 1TQ, UK
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8
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Candolin U, Goncalves S, Pant P. Parental care amplifies changes in offspring production in a disturbed environment. OIKOS 2021. [DOI: 10.1111/oik.08668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Ulrika Candolin
- Organismal and Evolutionary Biology, Univ. of Helsinki Helsinki Finland
| | - Sara Goncalves
- Organismal and Evolutionary Biology, Univ. of Helsinki Helsinki Finland
| | - Pankaj Pant
- Organismal and Evolutionary Biology, Univ. of Helsinki Helsinki Finland
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9
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Richardson J, Smiseth PT. Separating differential allocation by females from direct effects of male condition in a beetle. Behav Ecol 2021. [DOI: 10.1093/beheco/araa146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Differential allocation is the adjustment of reproductive allocation, typically by a female, in response to the quality of her male partner. A recent theoretical model suggests that differential allocation may influence trade-offs between reproductive traits within a breeding attempt. Furthermore, it is often difficult to distinguish differential allocation from direct effects of male condition. We address these gaps using a novel cross-fostering design to exclude direct effects of male condition and to test whether differential allocation affects trade-offs between and within breeding attempts. This design detects differential allocation as effects of a female’s mating partner and direct effects of male condition as effects of the larvae’s sire. We used the burying beetle Nicrophorus vespilloides, a species which adjusts reproductive allocation by culling some larvae after hatching. We used food deprivation to manipulate the nutritional condition of both the female’s mating partner and the larvae’s sire. We find clear evidence for differential allocation as females mating with food-deprived males had fewer larvae than females mating with control males. There was a trade-off between number and size of larvae when females mated with control males, but a positive relationship when females mated with food-deprived males. Thus, differential allocation influenced relationships between reproductive traits within a breeding attempt, but not necessarily through trade-offs. Instead, we suggest that there may be cryptic heterogeneity in quality among females or their mating partners that was only exposed when females mated with a male in poor condition.
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Affiliation(s)
- Jon Richardson
- Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh, UK
| | - Per T Smiseth
- Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh, UK
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10
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Cheron M, Angelier F, Ribout C, Brischoux F. Clutch quality is related to embryonic development duration, hatchling body size and telomere length in the spined toad (Bufo spinosus). Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract
Reproductive success is often related to parental quality, a parameter expressed through various traits, such as site selection, mate selection and energetic investment in the eggs or progeny. Owing to the complex interactions between environmental and parental characteristics occurring at various stages of the reproductive event, it is often complicated to tease apart the relative contributions of these different factors to reproductive success. Study systems where these complex interactions are simplified (e.g. absence of parental care) can help us to understand how metrics of parental quality (e.g. gamete and egg quality) influence reproductive success. Using such a study system in a common garden experiment, we investigated the relationships between clutch hatching success (a proxy of clutch quality) and offspring quality in an amphibian species lacking post-oviposition parental care. We found a relationship between clutch quality and embryonic development duration and hatchling phenotype. We found that hatchling telomere length was linked to hatching success. These results suggest that clutch quality is linked to early life traits in larval amphibians and that deciphering the influence of parental traits on the patterns we detected is a promising avenue of research.
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Affiliation(s)
- Marion Cheron
- Centre d’Etudes Biologiques de Chizé, CEBC-CNRS UMR 7372, 79360 Villiers en Bois,France
| | - Frédéric Angelier
- Centre d’Etudes Biologiques de Chizé, CEBC-CNRS UMR 7372, 79360 Villiers en Bois,France
| | - Cécile Ribout
- Centre d’Etudes Biologiques de Chizé, CEBC-CNRS UMR 7372, 79360 Villiers en Bois,France
| | - François Brischoux
- Centre d’Etudes Biologiques de Chizé, CEBC-CNRS UMR 7372, 79360 Villiers en Bois,France
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11
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Lange L, Bégué L, Brischoux F, Lourdais O. The costs of being a good dad: egg-carrying and clutch size impair locomotor performance in male midwife toads (Alytes obstetricans). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Parental care is widespread across the animal kingdom. Parental behaviours are beneficial by increasing offspring survival but induce significant costs to the parents. Because parental care is far more common in females, the associated reproductive costs have been largely studied in this sex. Although male parental care is likely to involve significant costs, it has been markedly less well investigated. We studied the costs of egg-carrying on locomotor performance in an amphibian species (Alytes obstetricans) with male parental care. We examined complementary parameters including hopping performance, righting response, hindleg muscle response to egg burden, and homing time in males carrying or not carrying eggs. We found that carrying males showed altered locomotor performance for most traits. In addition, alteration of performance was closely related to relative clutch size. Clutch desertion occurred in smaller individuals carrying larger relative clutch mass, and performance after desertion was similar to that of non-reproductive individuals. Overall, our study demonstrates that carrying eggs significantly alters male mobility and that performance–clutch size trade-offs are relevant in understanding the evolution of paternal care.
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Affiliation(s)
- Léa Lange
- Centre d’Études Biologiques de Chizé, CNRS et Université de la Rochelle – UMR 7372, Villiers en Bois, France
| | - Lauriane Bégué
- Centre d’Études Biologiques de Chizé, CNRS et Université de la Rochelle – UMR 7372, Villiers en Bois, France
| | - François Brischoux
- Centre d’Études Biologiques de Chizé, CNRS et Université de la Rochelle – UMR 7372, Villiers en Bois, France
| | - Olivier Lourdais
- Centre d’Études Biologiques de Chizé, CNRS et Université de la Rochelle – UMR 7372, Villiers en Bois, France
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
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12
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Rahman MM, Siddique A, Rahman MA, Rahman SM, Asaduzzaman M, Khanom M, Khatun MM, Hasan MM. The interactive effects of paternal size and offspring feeding strategy on offspring fitness of an Indian major carp
Labeo rohita
(Hamilton, 1822). AQUACULTURE RESEARCH 2020; 51:2421-2431. [DOI: 10.1111/are.14586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/18/2020] [Indexed: 09/27/2023]
Affiliation(s)
- Md. Moshiur Rahman
- Tokyo University of Marine Science and Technology Tokyo Japan
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
| | - Asif Siddique
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
| | - Md. Ashikur Rahman
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
| | - Sheikh Mustafizur Rahman
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
- Fish Resources Research Center King Faisal University Hofuf Al‐Ahsa Kingdom of Saudi Arabia
| | - Md. Asaduzzaman
- Department of Marine Bioresource Science Chittagong Veterinary and Animal Sciences University Chittagong Bangladesh
| | - Momotaz Khanom
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
| | - Mst. Muslima Khatun
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
| | - Md. Mehedi Hasan
- Fisheries & Marine Resource Technology Discipline Khulna University Khulna Bangladesh
- Sydney School of Veterinary Science Faculty of Science The University of Sydney Camden NSW Australia
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13
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Haaland TR, Wright J, Ratikainen II. Generalists versus specialists in fluctuating environments: a bet‐hedging perspective. OIKOS 2020. [DOI: 10.1111/oik.07109] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Thomas Ray Haaland
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Høgskoleringen 5 NO‐7044 Trondheim Norway
- Dept of Evolutionary Biology and Environmental Studies, Univ. of Zürich Winterthurerstrasse 190 CH‐8057 Zürich Switzerland
| | - Jonathan Wright
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Høgskoleringen 5 NO‐7044 Trondheim Norway
| | - Irja Ida Ratikainen
- Centre for Biodiversity Dynamics, Dept of Biology, Norwegian Univ. of Science and Technology Høgskoleringen 5 NO‐7044 Trondheim Norway
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14
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Abstract
In many species that form pair bonds, males display to their mate after pair formation. These displays elevate the female's investment into the brood. This is a form of cooperation because without the display, female investment is reduced to levels that are suboptimal for both sexes. The presence of such displays is paradoxical as in their absence the male should be able to invest extra resources directly into offspring, to the benefit of both sexes. We consider that the origin of these displays lies in the exploitation of preexisting perceptual biases which increase female investment beyond that which is optimal for her, initially resulting in a sexual conflict. We use a combined population genetic and quantitative genetic model to show how this conflict becomes resolved into sexual cooperation. A cooperative outcome is most likely when perceptual biases are under selection pressures in other contexts (e.g., detection of predators, prey, or conspecifics), but this is not required. Cooperation between pair members can regularly evolve even when this provides no net advantage to the pair and when the display itself reduces a male's contributions to raising the brood. The findings account for many interactions between the sexes that have been difficult to explain in the context of sexual selection.
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15
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Nusbaumer D, Marques da Cunha L, Wedekind C. Sperm cryopreservation reduces offspring growth. Proc Biol Sci 2019; 286:20191644. [PMID: 31551057 PMCID: PMC6784727 DOI: 10.1098/rspb.2019.1644] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/05/2019] [Indexed: 12/21/2022] Open
Abstract
Sperm cryopreservation is routinely used in reproductive medicine, livestock production and wildlife management. Its effect on offspring performance is often assumed to be negligible, but this still remains to be confirmed in well-controlled within-subject experiments. We use a vertebrate model that allows us to experimentally separate parental and environmental effects to test whether sperm cryopreservation influences offspring phenotype under stress and non-stress conditions, and whether such effects are male-specific. Wild brown trout (Salmo trutta) were stripped for their gametes, and a portion of each male's milt was cryopreserved. Then, 960 eggs were simultaneously fertilized with either non-cryopreserved or frozen-thawed semen and raised singly in the presence or absence of a pathogen. We found no significant effects of cryopreservation on fertilization rates, and no effects on growth, survival nor pathogen resistance during the embryo stage. However, fertilization by cryopreserved sperm led to significantly reduced larval growth after hatching. Males varied in genetic quality as determined from offspring performance, but effects of cryopreservation on larval growth were not male-specific. We conclude that cryopreservation causes a reduction in offspring growth that is easily overlooked because it only manifests itself at later developmental stages, when many other factors affect growth and survival too.
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Affiliation(s)
| | | | - Claus Wedekind
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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16
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Ratikainen II, Haaland TR, Wright J. Differential allocation of parental investment and the trade-off between size and number of offspring. Proc Biol Sci 2018; 285:20181074. [PMID: 30068679 PMCID: PMC6111174 DOI: 10.1098/rspb.2018.1074] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/09/2018] [Indexed: 02/06/2023] Open
Abstract
When parents decide how much to invest in current versus future offspring and how many offspring to divide their current investments between, the optimal decision can be affected by the quality of their partner. This differential allocation (DA) is highly dependent on exactly how partner quality affects reproductive costs and offspring benefits. We present a stochastic dynamic model of DA in which females care for a series of clutches when mated with males of different quality. In each reproductive event, females choose the size and number of offspring. We find that if partner quality affects reproductive costs, then DA in total reproductive investment occurs only via changes in the number of offspring. DA in the optimal size of the offspring occurs only if partner quality affects the offspring benefit function. This is mostly in the form of greater female investment per offspring as male quality decreases. Simultaneously, we find that adaptive DA increases the number of offspring, and thus the amount of total investment, as male quality increases. Only certain model scenarios produce the positive DA in offspring size seen in empirical studies, providing a predictive framework for DA and how partner quality affects reproductive costs and offspring benefits.
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Affiliation(s)
- Irja Ida Ratikainen
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim, Norway
| | - Thomas Ray Haaland
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim, Norway
| | - Jonathan Wright
- Department of Biology, Centre for Biodiversity Dynamics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim, Norway
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