Article
Cell Biology
Carl D. Soulsbury, Stuart Humphries
Summary: Over the last 50 years, sperm competition has been recognized as an important evolutionary force in shaping male ejaculate traits. The length of sperm has often been associated with faster swimming speed, but this relationship is more complex than previously thought. Different predictive models were tested, and the Constant Speed model was found to be more accurate in predicting the relationship between sperm length and velocity. Traditional models do not fully capture the biophysical interactions involved in sperm swimming. Future research should consider the microenvironment in which sperm operate and the importance of fertilizing environment.
Article
Behavioral Sciences
Rowan A. Lymbery, Brendan J. Alvaro, Jonathan P. Evans
Summary: This study investigated ejaculate investment in male guppies under different sperm competition risks and diet treatments. Contrary to predictions, males did not increase ejaculate expenditure under high sperm competition risk, and instead exhibited higher sperm velocity under low sperm competition risk. Furthermore, dietary restriction did not affect ejaculate traits in mature adult males. These unexpected findings may be related to the biology of guppies and their high levels of polyandry.
Review
Biology
Liam R. Dougherty, Michael J. A. Skirrow, Michael D. Jennions, Leigh W. Simmons
Summary: In many animal species, males exhibit different alternative reproductive tactics (ARTs) in obtaining fertilisations, but there is little evidence that ARTs differ substantially in investment into sperm and ejaculates across species. The incongruence between theoretical predictions and empirical results could be explained by the failure of theoretical models to account for differences in overall resource levels between males exhibiting different ARTs, as well as the inaccurate measurement of sperm or ejaculate traits in reflecting overall post-mating investment or affecting fertilisation success.
BIOLOGICAL REVIEWS
(2022)
Article
Parasitology
Luiz Fellipe Monteiro Couto, Luciana Maffini Heller, Dina Maria Beltran Zapa, Maria Ivete de Moura, Gustavo Lage Costa, Alliny Souza de Assis Cavalcante, Nathalia Braz Ribeiro, Thiago Souza Azeredo Bastos, Lorena Lopes Ferreira, Vando Edesio Soares, Guilherme Rocha Lino de Souza, Fabiano Antonio Cadioli, Welber Daniel Zanetti Lopes
Summary: This study investigated the presence of Trypanosoma vivax in semen and reproductive tissues of experimentally infected cattle and found that T. vivax DNA was present in the semen of infected animals. The seminal parameters of infected cattle showed changes, including decreased turbulence, motility, concentration, and vigor, as well as increased sperm abnormalities. The results highlight the importance of this disease for male breeding cattle and further research is needed to determine if sexual transmission can occur in cattle.
VETERINARY PARASITOLOGY
(2022)
Article
Psychology, Clinical
Tara DeLecce, Todd K. Shackelford, Virgil Zeigler-Hill, Bernhard Fink, Mohaned G. Abed
Summary: The study found no compensatory relationship between mate retention behavior and investment in ejaculate quality in human males, providing limited support for this hypothesis. Further research is needed to address questions about the nature of anti-cuckoldry tactic deployment in humans, especially concerning investment in ejaculate quality.
ARCHIVES OF SEXUAL BEHAVIOR
(2021)
Article
Multidisciplinary Sciences
Ariel F. Kahrl, Rhonda R. Snook, John L. Fitzpatrick
Summary: The fertilization environment plays a significant role in the evolution and diversification of sperm morphology across vertebrate species, but the impact of fertilization mode varies among sperm components and vertebrate clades.
NATURE COMMUNICATIONS
(2022)
Article
Cell Biology
Suzanne H. Alonzo, Kelly A. Stiver, Holly K. Kindsvater, Susan E. Marsh-Rollo, Bridget Nugent, Erem Kazancioglu
Summary: Through sperm competition driven sexual selection, immense variation in ejaculate allocation and sperm characteristics has evolved not only between species but also within males of a species. This study investigated differences in testes size, ejaculate production, and sperm morphology among male alternative reproductive types in the ocellated wrasse. Results showed that satellite males had larger testes, while sneakers produced smaller ejaculates but with larger sperm head size. Social interactions among males can influence sperm and ejaculate production.
Article
Ecology
Yoko Iwata, Noriyosi Sato, Noritaka Hirohashi, Yoshiro Watanabe, Warwick H. H. Sauer, Paul W. Shaw
Summary: The study found that different mating tactics in squid species can affect the quantitative and qualitative traits of male sperm, and the female's sperm storage mode and fertilization processes are important factors influencing this evolution; unlike consort males, sneaker males are more likely to face sperm competition risks; through adjustment of sperm packaging, different levels of sperm competition risk can be adapted to.
JOURNAL OF EVOLUTIONARY BIOLOGY
(2021)
Article
Cell Biology
Yentel Mateo-Otero, Estel Vinolas-Verges, Marc Llavanera, Jordi Ribas-Maynou, Jordi Roca, Marc Yeste, Isabel Barranco
Summary: The study found that aldose reductase B1 is abundantly expressed in the reproductive organs of boars, especially in the post-SRF fraction. However, no relationship was observed between the enzyme and sperm quality/functionality parameters.
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
(2021)
Article
Neurosciences
Nitzan Geva, Daniel Deitch, Alon Rubin, Yaniv Ziv
Summary: Hippocampal activity is critical for spatial memory, but the coding of hippocampal neurons gradually changes over time, a phenomenon known as representational drift. The passage of time and the amount of experience are two factors that affect memory, but their specific influence on hippocampal representational drift is still unclear.
Article
Biochemistry & Molecular Biology
Marta Olszewska, Oliwia Kordyl, Marzena Kamieniczna, Monika Fraczek, Piotr Jedrzejczak, Maciej Kurpisz
Summary: Epigenetic modifications, specifically methylation and hydroxymethylation, are associated with sperm chromatin protamination. The levels of these modifications are diversified in different populations of males and may be related to sperm motility and morphology. Measuring the 5mC/5hmC status of sperm DNA may serve as a prognostic marker for reproductive failure.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Review
Cell Biology
Katerina Turner, Nisha Solanki, Hassan O. Salouha, Tomer Avidor-Reiss
Summary: The sperm competition theory predicts that sperm evolve through a cascade of changes, including morphological diversification. A study on fish species found that internally fertilizing fish are more likely to evolve sperm with atypical centriolar composition compared to externally fertilizing fish. This finding supports the sperm competition theory.
Article
Cell Biology
Geoff A. Parker
Summary: These two papers discuss sperm competition, sexual selection, and the origin and evolution of gamete dimorphism, revealing the importance of sexual selection in biological evolution and influencing our understanding of sexual strategy differences between the sexes and gametic cells.
Article
Behavioral Sciences
Kristin A. Hook, W. David Weber, Heidi S. Fisher
Summary: This study reveals that sperm aggregation can improve motility, especially in viscous fluids, for species of deer mice that experience sperm competition. The size and quality of sperm aggregates vary among species and are associated with postcopulatory sexual selection.
BEHAVIORAL ECOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Elisa Morbiato, Silvia Cattelan, Andrea Pilastro, Alessandro Grapputo
Summary: Life-history theory suggests that ageing is one of the costs of reproduction. This study found that reproductive investment in male guppies is strongly associated with telomere length, indicating a trade-off between reproduction and maintenance at each stage of males' life in this species.
Article
Ecology
Sil H. J. van Lieshout, Alexandra M. Sparks, Amanda Bretman, Chris Newman, Christina D. Buesching, Terry Burke, David W. Macdonald, Hannah L. Dugdale
Summary: This study investigated telomere length variation in a wild population of European badgers, finding that individual variation in telomere length is primarily driven by environmental variation and there is no evidence for parental age at conception effects on offspring telomere length. Year and cohort explained greater proportions of the phenotypic variance in telomere length.
JOURNAL OF EVOLUTIONARY BIOLOGY
(2021)
Article
Evolutionary Biology
Martijn Hammers, Sjouke A. Kingma, Lotte A. van Boheemen, Alexandra M. Sparks, Terry Burke, Hannah L. Dugdale, David S. Richardson, Jan Komdeur
Summary: In cooperatively breeding species, alloparental care provided by helpers can mitigate the impact of parental senescence on offspring provisioning and survival. While the provisioning rate of female breeders and offspring survival decline with age, the presence of helpers helps alleviate these declines. Older female breeders recruit more helpers, leading to overall increased care for their brood.
Article
Biochemistry & Molecular Biology
Alexandra M. Sparks, Lewis G. Spurgin, Marco van der Velde, Eleanor A. Fairfield, Jan Komdeur, Terry Burke, David S. Richardson, Hannah L. Dugdale
Summary: Individual variation in telomere length is predictive of health and mortality risk. The relative influence of environmental and genetic variation on individual telomere length in wild populations remains poorly understood. Parental age at conception may influence offspring telomere length, and heritability and evolvability of telomere length were found to be low in the studied population.
Article
Biochemistry & Molecular Biology
Sil H. J. van Lieshout, Elisa P. Badas, Julius G. Bright Ross, Amanda Bretman, Chris Newman, Christina D. Buesching, Terry Burke, David W. Macdonald, Hannah L. Dugdale
Summary: The study found that the telomere length in European badgers during early life is associated with weather conditions and group size, while no significant association was found between telomere length and group size in early adulthood. Additionally, early-life telomere length is positively correlated with cub survival probability.
Article
Biochemistry & Molecular Biology
Thomas J. Brown, Lewis G. Spurgin, Hannah L. Dugdale, Jan Komdeur, Terry Burke, David S. Richardson
Summary: The length of telomeres, which are important markers of biological age, can both shorten and lengthen with age and environmental stress. This study found that telomere lengthening in females occurs in less stressful circumstances, while telomere shortening is associated with greater stress. Males, on the other hand, did not show an association between telomere dynamics and key stressors. Individuals with lengthened telomeres, both females and males, had improved subsequent survival compared to those with unchanged or shortened telomeres.
Article
Ecology
Michela Busana, Dylan Z. Childs, Terrence A. Burke, Jan Komdeur, David S. Richardson, Hannah L. Dugdale
Summary: The social environment can impact individual fitness and population dynamics, especially in species with facultative cooperative breeding. In such species, helping behavior can benefit dominants by increasing reproductive rates and reducing mortality. Our study on Seychelles warblers found that stochastic variation in dominants' reproductive rates influences population dynamics, helping behavior promotes population persistence, and there are only early-life differences in direct fitness between helpers and non-helpers.
JOURNAL OF ANIMAL ECOLOGY
(2022)
Article
Ecology
Sara Raj Pant, Maaike A. Versteegh, Martijn Hammers, Terry Burke, Hannah L. Dugdale, David S. Richardson, Jan Komdeur
Summary: This study analyzed the reproductive data of Seychelles warblers and found that although extra-pair paternity (EPP) may not have a significant effect on the opportunity for selection compared to genetic monogamy, it still contributes significantly to the lifetime and age-specific opportunity for selection.
Article
Multidisciplinary Sciences
Ziva Alif, Jamie Dunning, Heung Ying Janet Chik, Terry Burke, Julia Schroeder
Summary: Fitness is difficult to accurately measure in evolutionary theory. Short-term fitness metrics, such as the number of offspring produced, are commonly used as proxies in wild study systems. This study compared different short-term fitness metrics obtained at different offspring life stages and found that they best predicted long-term fitness when measured at the recruit stage.
Article
Multidisciplinary Sciences
Lina M. Giraldo-Deck, Jasmine L. Loveland, Wolfgang Goymann, Barbara Tschirren, Terry Burke, Bart Kempenaers, David B. Lank, Clemens Kuepper
Summary: In the ruff Calidris pugnax, a supergene controlled by chromosomal inversions determines three male mating morphs, with female individuals showing differences in reproductive success. Faeder females with un-recombined inversion haplotypes have lower reproductive success compared to Independent females without the inversion, while Satellite females with recombined haplotypes show intermediate reproductive performance. This suggests that intralocus conflicts may play a key role in the evolution and maintenance of supergene variants.
NATURE COMMUNICATIONS
(2022)
Article
Microbiology
Charli S. Davies, Sarah F. Worsley, Kathryn H. Maher, Jan Komdeur, Terry Burke, Hannah L. Dugdale, David S. Richardson
Summary: This study found that components of the host's immune system, specifically MHC-I and MHC-II variation, can influence the diversity and composition of the gut microbiome. This suggests that host-microbiome coevolution may play a role in maintaining immunogenetic variation within populations.
Article
Genetics & Heredity
Sophie Bennett, Antje Girndt, Alfredo Sanchez-Tojar, Terry Burke, Mirre Simons, Julia Schroeder
Summary: Offspring of older parents in many species have decreased longevity, a faster aging rate, and lower fecundity. Telomeres, biomarkers of aging that tend to shorten as individuals age, may provide insights into the mechanisms of parental age effects. This study on house sparrows found that the effect of parental age on telomere length was sex-specific, with older fathers producing daughters with longer telomere lengths. The telomere length of chicks increased between 0.5 and 3 months of age, which is unusual in birds but more commonly seen in non-avian taxa. Further research on similar patterns in different species and taxa will contribute to a better understanding of telomere length variation and its evolution.
FRONTIERS IN GENETICS
(2022)
Article
Ecology
Marta Precioso, Mercedes Molina-Morales, Deborah A. Dawson, Terry A. Burke, Juan G. Martinez
Summary: This study evaluated the long-term effects of ethanol storage on telomere length measurements, finding a pattern of decreasing loss of telomere sequence with storage time that stops after approximately 4 years. This suggests that telomeres may degrade in blood samples stored in ethanol, highlighting the importance of evaluating the long-term effects of storage on telomere measurements.
EVOLUTIONARY ECOLOGY
(2022)
Article
Ecology
Janske van de Crommenacker, Martijn Hammers, Hannah L. Dugdale, Terry A. Burke, Jan Komdeur, David S. Richardson
Summary: Early-life environmental conditions can have lasting effects on later-life fitness. Individuals may use a predictive adaptive response to maximize fitness based on their early-life conditions. Our study tested predictions of the Future Lifespan Expectation hypothesis, and found a relationship between poor early-life conditions and subsequent fitness, but caution is needed when using juvenile telomere length as a measure of early-life conditions.
ECOLOGY AND EVOLUTION
(2022)
Article
Behavioral Sciences
Mirjam J. Borger, David S. Richardson, Hannah Dugdale, Terry Burke, Jan Komdeur
Summary: Species are facing challenges from rapidly changing environments, such as increased frequency of extreme weather events. While natural selection acts slowly, organisms may use mechanisms like cooperative breeding to cope with rapid change. However, our study on the Seychelles warbler found that low rainfall was associated with reduced reproductive output, but cooperative breeding did not seem to buffer against harsh environments. This highlights the importance of considering the interaction between environment and life histories when studying species survival.
Article
Evolutionary Biology
Alexandra M. Sparks, Martijn Hammers, Jan Komdeur, Terry Burke, David S. Richardson, Hannah L. Dugdale
Summary: Parental age has significant effects on offspring's life span and lifetime reproductive success, with the impact being sex-dependent. These intergenerational effects play a crucial role in determining long-term offspring performance and contribute to the variation in longevity and fitness in the wild.