Sperm Morphology and Male Age in Black-Throated Blue Warblers, an Ecological Model System

Extra-pair paternity may drive selection on spermatozoa and ejaculate characteristics through sperm competition and cryptic female choice. Here, we examine sperm morphology in the black-throated blue warbler (Setophaga caerulescens), an ecological model species where extra-pair paternity is frequent and is linked with male age. We test whether sperm morphology relates to several aspects of male phenotype known or suspected to affect extra-pair paternity success. Sperm morphology did not correlate with the size of the white wing spot, a social status signal, nor with the volume of the cloacal protuberance. However, older males tended to have longer sperm cells. Although the sample size was limited, this pattern is intriguing, as longer cells may be advantageous in post-copulatory sexual selection and older males have larger testes and higher extra-pair paternity success in this species. Changes in sperm morphology with age are not observed in other birds, though they have been observed in insects and fishes. More research on sperm morphology is needed to clarify its role in extra-pair fertilizations in this well-studied species.

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Separating the effects of male age and past mating effort on paternity success under sperm competition

10.32942/osf.io/yqv86 ◽

2021 ◽

Author(s):

Upama Aich ◽

Megan Head ◽

Rebecca Fox ◽

Michael D Jennions

Keyword(s):

Sperm Competition ◽

General Pattern ◽

Male Mating ◽

Mating Effort ◽

Reproductive Senescence ◽

Young Males ◽

Male Age ◽

Mating History ◽

Paternity Success ◽

Older Males

Older males often perform poorly under post-copulatory sexual selection. It is unclear, however, whether reproductive senescence is due to male age itself or the accumulated costs of the higher lifetime mating effort that is usually associated with male age. To date, very few studies have accounted for male mating history when testing for the effect of male age on sperm traits, and none test how age and past mating history influence paternity success under sperm competition. Here, we experimentally manipulate male mating history to tease apart its effects from that of age on ejaculate traits and paternity in the mosquitofish, Gambusia holbrooki. We found that old, naive males had more sperm than old, experienced males, while the reverse was true for young males. In contrast, neither male age nor mating history affected sperm velocity. Finally, using artificial insemination to experimentally control the number of sperm per male, we found that old males sired significantly more offspring than young males independent of their mating history. Our results highlight that the general pattern of male reproductive senescence described in many taxa may often be affected by two naturally confounding factors, male mating history and sperm age, rather than male age itself.

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Male age alone predicts paternity success under sperm competition when effects of age and past mating effort are experimentally separated

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0979 ◽

2021 ◽

Vol 288 (1955) ◽

pp. 20210979

Author(s):

Upama Aich ◽

Megan L. Head ◽

Rebecca J. Fox ◽

Michael D. Jennions

Keyword(s):

Sperm Competition ◽

General Pattern ◽

Male Mating ◽

Mating Effort ◽

Reproductive Senescence ◽

Young Males ◽

Male Age ◽

Mating History ◽

Paternity Success ◽

Older Males

Older males often perform poorly under post-copulatory sexual selection. It is unclear, however, whether reproductive senescence is because of male age itself or the accumulated costs of the higher lifetime mating effort that is usually associated with male age. To date, very few studies have accounted for mating history and sperm storage when testing the effect of male age on sperm traits, and none test how age and past mating history influence paternity success under sperm competition. Here, we experimentally manipulate male mating history to tease apart its effects from that of age on ejaculate traits and paternity in the mosquitofish, Gambusia holbrooki . We found that old, naive males had more sperm than old, experienced males, while the reverse was true for young males. By contrast, neither male age nor mating history affected sperm velocity. Finally, using artificial insemination to experimentally control the number of sperm per male, we found that old males sired significantly more offspring than young males independently of their mating history. Our results highlight that the general pattern of male reproductive senescence described in many taxa may often be affected by two naturally confounding factors, male mating history and sperm age, rather than male age itself.

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Developing genomic resources for an emerging ecological model species Senecio lautus

10.14264/uql.2015.456 ◽

2015 ◽

Cited By ~ 1

Author(s):

Huanle Liu

Keyword(s):

Ecological Model ◽

Model Species ◽

Genomic Resources

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Male age mediates reproductive investment and response to paternity assurance

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.1124 ◽

2013 ◽

Vol 280 (1764) ◽

pp. 20131124 ◽

Cited By ~ 26

Author(s):

Kyle M. Benowitz ◽

Megan L. Head ◽

Camellia A. Williams ◽

Allen J. Moore ◽

Nick J. Royle

Keyword(s):

Prenatal Care ◽

Reproductive Investment ◽

Burying Beetle ◽

Offspring Performance ◽

Male Response ◽

Male Age ◽

Paternity Assurance ◽

Trade Offs ◽

Nicrophorus Vespilloides ◽

Older Males

Theory predicts that male response to reduced paternity will depend on male state and interactions between the sexes. If there is little chance of reproducing again, then males should invest heavily in current offspring, regardless of their share in paternity. We tested this by manipulating male age and paternity assurance in the burying beetle Nicrophorus vespilloides . We found older males invested more in both mating effort and parental effort than younger males. Furthermore, male age, a component of male state, mediated male response to perceived paternity. Older males provided more prenatal care, whereas younger males provided less prenatal care, when perceived paternity was low. Adjustments in male care, however, did not influence selection acting indirectly on parents, through offspring performance. This is because females adjusted their care in response to the age of their partner, providing less care when paired with older males than younger males. As a result offspring, performance did not differ between treatments. Our study shows, for the first time, that a male state variable is an important modifier of paternity–parental care trade-offs and highlights the importance of social interactions between males and females during care in determining male response to perceived paternity.

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De novo transcriptome sequencing in a songbird, the dark-eyed junco (Junco hyemalis): genomic tools for an ecological model system

BMC Genomics ◽

10.1186/1471-2164-13-305 ◽

2012 ◽

Vol 13 (1) ◽

pp. 305 ◽

Cited By ~ 28

Author(s):

Mark P Peterson ◽

Danielle J Whittaker ◽

Shruthi Ambreth ◽

Suhas Sureshchandra ◽

Aaron Buechlein ◽

...

Keyword(s):

Transcriptome Sequencing ◽

Ecological Model ◽

De Novo ◽

Model System ◽

Junco Hyemalis ◽

De Novo Transcriptome ◽

Genomic Tools ◽

De Novo Transcriptome Sequencing ◽

Ecological Model System

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Age-dependent trajectories differ between within-pair and extra-pair paternity success

Journal of Evolutionary Biology ◽

10.1111/jeb.13058 ◽

2017 ◽

Vol 30 (5) ◽

pp. 951-959 ◽

Cited By ~ 6

Author(s):

Y.-H. Hsu ◽

M. J. P. Simons ◽

J. Schroeder ◽

A. Girndt ◽

I. S. Winney ◽

...

Keyword(s):

Extra Pair Paternity ◽

Age Dependent ◽

Paternity Success

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Extra-pair paternity and mate-guarding behaviour in the brown thornbill

Australian Journal of Zoology ◽

10.1071/zo02037 ◽

2002 ◽

Vol 50 (6) ◽

pp. 565 ◽

Cited By ~ 5

Author(s):

David J. Green ◽

Anne Peters ◽

Andrew Cockburn

Keyword(s):

Mate Guarding ◽

Male Size ◽

Fertile Period ◽

Young Males ◽

Extra Pair Paternity ◽

Close Proximity ◽

Multilocus Dna Fingerprinting ◽

Socially Monogamous ◽

The Relationship ◽

Older Males

We used multilocus DNA fingerprinting to assess parentage in the brown thornbill, Acanthiza pusilla, a socially monogamous Australian passerine. Extra-pair paternity was uncommon (6.2% of 178 offspring; 11.9% of 67 broods) and there was no evidence of intra-specific brood parasitism. Extra-pair paternity was limited because pairs spent more time together when females were fertile and males were able to evict intruding males before they could approach the female. Males were responsible for the close proximity of partners during the fertile period. Mate guarding therefore appears to be a male tactic aimed at preventing female infidelity rather than a cooperative behaviour of the pair aimed at preventing extra-pair copulations and/or female harassment. Females did not attempt to escape male guarding and were rarely observed to solicit copulations from intruding males. Nevertheless, females paired to smaller and younger males were more likely to cuckold their mates than females paired to larger and older males. This suggests that females may be more likely to seek or accept extra-pair matings when paired to small, young males or that old, large males are better at preventing their mates from engaging in extra-pair copulations. We found that male age but not male size influences mate-guarding behaviour. Older males tended to respond more aggressively to intruders. We therefore speculate that the relationship between male size/age and extra-pair paternity in brown thornbills may arise because female thornbills prefer large males as mates but are unable to express this preference as easily when paired to older males.

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The aging male: Relationship between male age, sperm quality and sperm DNA damage in an unselected population of 3124 men attending the fertility centre for the first time

Archivio Italiano di Urologia e Andrologia ◽

10.4081/aiua.2018.4.254 ◽

2019 ◽

Vol 90 (4) ◽

pp. 254-259 ◽

Cited By ~ 5

Author(s):

Alessandro Colasante ◽

Maria Giulia Minasi ◽

Filomena Scarselli ◽

Valentina Casciani ◽

Vincenzo Zazzaro ◽

...

Keyword(s):

Dna Damage ◽

Sperm Morphology ◽

Semen Quality ◽

Sperm Quality ◽

World Health ◽

Semen Parameters ◽

Sperm Dna Fragmentation ◽

Sperm Dna Damage ◽

Male Age ◽

Sperm Dna

Objective: the aim of our study was to put forward insights to treat any possible correlation among sperm quality, sperm DNA damage and male age as they may have fertility implications for men who choose to delay fatherhood. Materials and methods: Our study is a non-interventional retrospective analysis of 3124 semen samples from patients that were investigated for the conventional semen parameters. Tunel test assay was set up for the evaluation of the sperm DNA fragmentation index (DFI). We applied the Kappa index to compare both the 1999 and the 2010 World Health Organization (WHO) reference criteria to evaluate the competence of such semen parameters categorization during the standard routine of our laboratory. Results: With regards to our findings, it is possible to underline a significant relationship between aging and semen volume (p = 0.001), motility (p = 0.009), semen viscosity (p < 0.003) and sperm DNA damage (p < 0.009). We found a trend when focusing on the semen concentration (p = 0.05). The analysis of sperm morphology did not show any influence with advancing age (p = 0.606). When comparing both the 1999 and the 2010 WHO scales we found no accordance in the appraisal of sperm morphology but a very good one in the evaluation of the other parameters. Conclusions: Conventional semen analysis represents the opportunity to draw up a proxy insight on the male fertility status even if semen quality can only indirectly assess the probability of pregnancy. Several studies have verified a decay in the male reproductive system, sperm quality and fertility with advancing age although the reported results are not yet conclusive. Our results substantially agree with those findings outlined in the literature. Moreover we find that the discrepancy between the two WHO reference scales would eventually lead to an improper diagnosis of infertility.

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