Article
Behavioral Sciences
Marco Demont, Paul Ward, Wolf U. Blanckenhorn, Stefan Luepold, Oliver Y. Martin, Luc F. Bussiere
Summary: The study revealed a skew in sperm storage across female spermathecae, with the quantity of second-male sperm stored generally decreasing with increasing spermathecal size. Factors such as copula duration and timing of oviposition also influenced the proportion of sperm stored by the second male. Interestingly, there was a strong correlation between the proportion of second-male stored sperm and paternity success, highlighting the significance of sperm competition in postcopulatory sexual selection.
BEHAVIORAL ECOLOGY
(2021)
Article
Ecology
Sara E. E. Lipshutz, Samuel J. J. Torneo, Kimberly A. A. Rosvall
Summary: Sexual selection drives trait variation, and male competition for mating opportunities is linked to sperm size. The influence of female-female competition and male-male competition on sperm morphology is not well understood. We examined two species with socially polyandrous mating systems, finding that the species with greater polyandry had longer midpieces and tails in their sperm, as well as lower intraejaculate variation in tail length. These results suggest that female-female competition may shape male-male competition by selecting for longer and less variable sperm traits.
AMERICAN NATURALIST
(2023)
Article
Behavioral Sciences
Charel Reuland, Brett M. Culbert, Erika Fernlund Isaksson, Ariel F. Kahrl, Alessandro Devigili, John L. Fitzpatrick
Summary: The study reveals a positive relationship between social status and ejaculate quality in the pygmy halfbeak fish, with dominant males producing higher quality ejaculates under conditions of frequent male-male interactions. Additionally, dominant males are in better physical condition, growing faster and possessing larger livers, suggesting a possible condition dependence of competitive traits. Female presence or absence did not affect sperm swimming speed or testes mass, highlighting the importance of male-male behavioral interactions in driving social-status-dependent differences in ejaculate traits.
BEHAVIORAL ECOLOGY
(2021)
Article
Genetics & Heredity
Dawn S. Chen, Andrew G. Clark, Mariana F. Wolfner
Summary: In a study on Drosophila, researchers found that inhibiting the activity of Tdc2 neurons in females resulted in a higher proportion of offspring from the first male. This suggests that octopaminergic/tyraminergic signaling plays a role in biased sperm usage in multiply-mated females, and highlights a new role for the female nervous system in postcopulatory sexual selection.
Article
Evolutionary Biology
Matthew C. Kustra, Suzanne H. Alonzo
Summary: In contrast to pre-mating sexual selection, little theoretical research has focused on the coevolution of postmating traits via cryptic female choice. This study used simulation models to investigate the impact of nondirectional cryptic female choice on male-mediated postmating processes, as well as the interaction between sperm competition risk, cryptic female choice strength, and sperm traits. The results showed that incorporating cryptic female choice can result in reduced male investment in ejaculates. It also revealed that genetic correlations between cryptic female choice and sperm traits can evolve even with weak cryptic female choice and low sperm competition risk.
Article
Cell Biology
Melissah Rowe, Annabel Van Oort, Lyanne Brouwer, Jan T. Lifjeld, Michael S. Webster, Joseph F. Welklin, Daniel T. Baldassarre
Summary: This study found that sperm quantity (indicated by cloacal protuberance volume) was associated with reproductive success in male red-backed fairy-wrens, while sperm morphology was not. This suggests that males use a large number of sperm as a defensive strategy to protect within-pair paternity success in a system with high risk of sperm competition and female control of copulation.
Article
Biology
Jeremias N. Brand, Luke J. Harmon, Lukas Schaerer
Summary: This study investigates the correlation between sex allocation and reproductive behavior in hermaphroditic flatworms. The study finds that hypodermic insemination leads to a more female-biased sex allocation and is associated with selfing or biparental inbreeding. Additionally, a trade-off between male and female reproduction is observed, as well as a correlation between morphological indicators and sex allocation.
Article
Biology
Jessica H. Hadlow, Jonathan P. Evans, Rowan A. Lymbery
Summary: Female reproductive fluids (FRFs) play crucial roles in reproductive functions, but their interactions with sperm under different environmental conditions are not well understood. This study investigated the effects of ejaculate age and FRF on sperm traits in a mussel species and found that FRF altered the effects of ejaculate age on sperm motility, with longer-lived sperm exhibiting stronger responses to FRF. There was also significant variation among males in the relationship between sperm motility and ejaculate age, which was only observed in the presence of FRF. These findings highlight the importance of considering female reproductive physiology in understanding sperm phenotypic plasticity.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Article
Cell Biology
Ariel F. Kahrl, Matthew C. Kustra, Aaron M. Reedy, Rachana S. Bhave, Heidi A. Seears, Daniel A. Warner, Robert M. Cox
Summary: This study measured univariate and multivariate selection on sperm traits in a wild population of brown anole lizards. Significant negative directional and quadratic selection were found on sperm count, but no selection on other sperm traits or trait combinations was detected. The results suggest pressure on males to produce many small ejaculates and mate frequently over a six-month reproductive season.
Article
Cell Biology
Charel Reuland, Leigh W. Simmons, Stefan Lupold, John L. Fitzpatrick
Summary: In polyandrous species, males face reproductive competition before and after mating, shaping the evolution of pre- and postcopulatory traits with differential resource allocation. Bovids and cervids exhibit accelerated evolution of male weaponry but slower evolution of sperm dimensions. Strong selection acts on both pre- and postcopulatory traits, with distinct evolutionary rates among different sperm components.
Article
Agriculture, Dairy & Animal Science
Mei Matsuzaki, Noritaka Hirohashi, Masaoki Tsudzuki, Mohammad Ibrahim Haqani, Teruo Maeda, Shusei Mizushima, Tomohiro Sasanami
Summary: Research has shown that in birds, sperm from the dominant black (DB) strain has a better ability to enter the sperm storage tubules (SST), resulting in higher fertilization success. This may be due to the longer flagellum and midpiece of DB sperm, allowing them to swim faster in a high viscosity medium.
Article
Entomology
R. Antonio Gomez, David Mercati, Pietro Lupetti, Paolo P. Fanciulli, Romano Dallai
Summary: This study examines the reproductive anatomy of Apotomus ground beetles and finds a positive evolutionary correlation between male and female genital organs, suggesting potential shifts in sexual selection.
ARTHROPOD STRUCTURE & DEVELOPMENT
(2023)
Article
Ecology
Alessio N. De Nardo, Jeannine Roy, Sonja H. Sbilordo, Stefan Lupold
Summary: The study found that larger males were more successful in mating in competitive environments, while smaller males had shorter mating latencies in noncompetitive settings. Smaller males also tended to transfer more sperm during mating, displace a larger proportion of resident sperm, and achieve higher paternity shares per mating.
Article
Biology
Anthony J. Geneva, Sungdae Park, Dan G. Bock, Pietro L. H. de Mello, Fatih Sarigol, Marc Tollis, Colin M. Donihue, R. Graham Reynolds, Nathalie Feiner, Ashley M. Rasys, James D. Lauderdale, Sergio G. Minchey, Aaron J. Alcala, Carlos R. Infante, Jason J. Kolbe, Dolph Schluter, Douglas B. Menke, Jonathan B. Losos
Summary: Rapid technological improvements have made high-quality genome assemblies more accessible, allowing non-traditional and emerging model species to be studied at the genome level. This study presents a complete chromosome-scale genome assembly for the brown anole lizard, Anolis sagrei, and proposes a hypothesis for the evolutionary history of its sex chromosomes.
COMMUNICATIONS BIOLOGY
(2022)
Article
Ecology
Upama Aich, Timothee Bonnet, Megan L. Head, Michael D. Jennions
Summary: Using eastern mosquitofish for experiments, this study found that old males and males with no mating experience spent more time approaching females and attempting to mate than young males and those with greater mating experience. Old males benefited from previous mating experience, while young males did not.
Article
Biochemistry & Molecular Biology
Tiantian Ren, Ariel F. Kahrl, Martin Wu, Robert M. Cox
Article
Zoology
Ariel F. Kahrl, Robert M. Cox
JOURNAL OF HERPETOLOGY
(2017)
Article
Zoology
Ariel F. Kahrl, Brittney M. Ivanov, Katharina C. Wollenberg Valero, Michele A. Johnson
Article
Ecology
Ariel F. Kahrl, Michele A. Johnson, Robert M. Cox
JOURNAL OF EVOLUTIONARY BIOLOGY
(2019)
Article
Ecology
Amy Rowley, Lisa Locatello, Ariel Kahrl, Mariana Rego, Annika Boussard, Eduardo Garza-Gisholt, Ryan M. Kempster, Shaun P. Collin, Eva Giacomello, Maria C. Follesa, Cristina Porcu, Jonathan P. Evans, Fabio Hazin, Francisco Garcia-Gonzalez, Toby Daly-Engel, Carlotta Mazzoldi, John L. Fitzpatrick
JOURNAL OF EVOLUTIONARY BIOLOGY
(2019)
Article
Behavioral Sciences
Hannah J. P. Ogden, Raissa A. de Boer, Alessandro Devigili, Charel Reuland, Ariel F. Kahrl, John L. Fitzpatrick
BEHAVIORAL ECOLOGY
(2020)
Article
Ecology
Matthew C. Kustra, Ariel F. Kahrl, Aaron M. Reedy, Daniel A. Warner, Robert M. Cox
Article
Behavioral Sciences
Charel Reuland, Brett M. Culbert, Erika Fernlund Isaksson, Ariel F. Kahrl, Alessandro Devigili, John L. Fitzpatrick
Summary: The study reveals a positive relationship between social status and ejaculate quality in the pygmy halfbeak fish, with dominant males producing higher quality ejaculates under conditions of frequent male-male interactions. Additionally, dominant males are in better physical condition, growing faster and possessing larger livers, suggesting a possible condition dependence of competitive traits. Female presence or absence did not affect sperm swimming speed or testes mass, highlighting the importance of male-male behavioral interactions in driving social-status-dependent differences in ejaculate traits.
BEHAVIORAL ECOLOGY
(2021)
Article
Behavioral Sciences
Callum S. McDiarmid, Roger Li, Ariel F. Kahrl, Melissah Rowe, Simon C. Griffith
Summary: Research on sperm is important in various fields such as ecology and evolution. Sperm Sizer, a freely available Java program, can semi-automate the process of measuring sperm length efficiently. The program produces high quality sperm length data and can be used in various species.
BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY
(2021)
Article
Cell Biology
Ariel F. Kahrl, Matthew C. Kustra, Aaron M. Reedy, Rachana S. Bhave, Heidi A. Seears, Daniel A. Warner, Robert M. Cox
Summary: This study measured univariate and multivariate selection on sperm traits in a wild population of brown anole lizards. Significant negative directional and quadratic selection were found on sperm count, but no selection on other sperm traits or trait combinations was detected. The results suggest pressure on males to produce many small ejaculates and mate frequently over a six-month reproductive season.
Article
Ecology
Ariel F. Kahrl, Rhonda R. Snook, John L. Fitzpatrick
Summary: The study reveals that fertilization mode is a key factor influencing the evolution of sperm length across animals. Species with sperm diluted in aquatic environments (external fertilizers and spermcasters) have shorter sperm, while species with sperm directly transferred to females (internal fertilizers) have longer sperm. Additionally, sperm length evolves faster and with more adaptive shifts in species where sperm operate within females (e.g. spermcasters and internal fertilizers).
NATURE ECOLOGY & EVOLUTION
(2021)
Article
Ecology
Amelie Fargevieille, Aaron M. Reedy, Ariel F. Kahrl, Timothy S. Mitchell, Andrew M. Durso, David M. Delaney, Phillip R. Pearson, Robert M. Cox, Daniel A. Warner
Summary: The composition of founding populations, including propagule size and sex ratio, can influence offspring production and population growth during early stages of biological invasion. Larger propagule size leads to higher offspring production, while female-biased propagules result in positive population growth in the first year.
JOURNAL OF ANIMAL ECOLOGY
(2022)
Article
Behavioral Sciences
Erika Fernlund Isaksson, Charel Reuland, Ariel F. Kahrl, Alessandro Devigili, John L. Fitzpatrick
Summary: This study examines the effects of resource restriction on pre- and post-copulatory traits in male pygmy halfbeaks. The results show that resource restriction leads to reduced body size, beak size, courtship behavior, and testes size, but unexpectedly, the restricted-diet group had a larger area of red color on the beak and fins after the diet treatment.
BEHAVIORAL ECOLOGY
(2022)
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
Zoology
Charel Reuland, Brett M. Culbert, Alessandro Devigili, Ariel F. Kahrl, John L. Fitzpatrick