Strategic investment in sperm removal behaviour in a bushcricket
Foraita M, Lehfeldt S, Reinhold K, Ramm SA (2017)
Journal of Insect Behavior. DOI: 10.1007/s10905-017-9608-2
We investigate variation in this intriguing sperm removal behaviour in the bushcricket Metaplastes ornatus, finding that males conserve investment when paired with unmated females.
Self-fertilization, sex allocation and spermatogenesis kinetics in the hypodermically-inseminating flatworm Macrostomum pusillum
Giannakara A, Ramm SA (2017)
Journal of Experimental Biology. DOI: 10.1242/jeb.149682
We demonstrate the ability of M. pusillum to self-fertilize, and present a series of findings suggesting that this is a frequent and maybe even the preferred reproductive mode of this species.
Exploring the sexual diversity of flatworms: ecology, evolution and the molecular biology of reproduction
Ramm SA (2017)
Molecular Reproduction & Development. DOI: 10.1002/mrd.22669
I review various “lifestyle choices” made by flatworms, such as whether to be free-living or parasitic; to reproduce sexually or asexually; to be separate-sexed or hermaphroditic; and if the latter, whether to outcross or self-fertilise as well as how to optimise sex allocation.
Experimentally evolved and phenotypically plastic responses to enforced monogamy in a hermaphroditic flatworm
Janicke T, Sandner P, Ramm SA, Vizoso DB, Schärer L (2016)
Journal of Evolutionary Biology. DOI: 10.1111/jeb.12910
Based on 32 selection lines evolving for 20 generations, we show that many sexual traits did not diverge under different mating regimes, but continued to exhibit substantial phenotypic plasticity.
Sperm competition-induced plasticity in the speed of spermatogenesis
Giannakara A, Schärer L, Ramm SA (2016)
BMC Evolutionary Biology 16: 60. DOI: 10.1186/s12862-016-0629-9
The first experimental evidence for adaptive plasticity in spermatogenesis speed: worms raised under more competitive conditions not only make more sperm, but make each one faster.
Integrating perspectives on rodent sperm competition
Ramm SA, Stockley P (2016)
Advances in the Study of Behavior 48. DOI: 10.1016/bs.asb.2016.02.003
An in-depth review of male adaptations to sperm competition in this model vertebrate group, including studies of copulatory behaviour, sperm production and allocation, seminal fluid and genitalia.
Schärer L, Ramm SA (2016)
Chapter 160 in Encyclopedia of Evolutionary Biology (R. Kliman, ed.). Academic Press.
A primer on evolutionary thinking about sex in both simultaneous and sequential hermaphrodites.
Sperm competition risk drives plasticity in seminal fluid composition
Ramm SA, Edward DA, Claydon AJ, Hammond DE, Brownridge P, Hurst JL, Beynon RJ, Stockley P (2015)
BMC Biology 13: 87. DOI: 10.1186/s12915-015-0197-2
Using proteomics methods, we reveal how male mice adjust seminal fluid protein production in response to social environmental cues.
Male birch catkin bugs vary copula duration to invest more in matings with novel females
Reinhold K, Engqvist L, Consul A, Ramm SA (2015)
Animal Behaviour 109: 161–166 DOI: 10.1016/j.anbehav.2015.08.020
We report a series of experiments that collectively imply strategic allocation of mating effort my male birch catkin bugs, in favour of novel females.
Hypodermic self-insemination as a reproductive assurance strategy
Ramm SA, Schlatter A, Poirier M, Schärer L (2015)
Proceedings of The Royal Society B Biological Sciences 282: 20150660. DOI: 10.1098/rspb.2015.0660
Experimental evidence that Macrostomum hystrix flatworms use a striking mechanism of self-injecting sperm into their own body in order to self-fertilise their eggs.
Making the complex simple: a comment on Valcu and Kempenaers (Invited Commentary)
Ramm SA (2015)
Behavioral Ecology 26: 16. DOI: 10.1093/beheco/aru167
A commentary to accompany the publication of Valcu and Kempenaers’ Invited Review on “Proteomics in behavioral ecology“
Sperm competition and the evolution of reproductive systems (Editorial)
Ramm SA (2014)
Molecular Human Reproduction 20(12): 1159–1160. DOI: 10.1093/molehr/gau076
Introduction to a special issue of MHR presenting four reviews on various topics linked to sperm competition.
Sperm competition and the evolution of spermatogenesis
Ramm SA, Schärer L, Ehmcke J, Wistuba J (2014)
Molecular Human Reproduction 20(12): 1169–1179. DOI: 10.1093/molehr/gau070
This review focuses on how sperm competition has been a crucial selection pressure shaping various aspects of spermatogenesis.
Sexual conflict in hermaphrodites
Schärer L, Janicke T, Ramm SA (2014)
Cold Spring Harbor Perspectives in Biology. DOI: 10.1101/cshperspect.a017673
We review how sexual conflict concepts can be applied to hermaphrodites. Also included as one chapter in: Rice WR & Gavrilets S (eds.) The Genetics and Biology of Sexual Conflict. Cold Spring Harbor Laboratory Press.
Sequential male mate choice under sperm competition risk
Ramm SA, Stockley P (2014)
Behavioral Ecology 25 (3): 660–667. DOI: 10.1093/beheco/aru037
Male house mice can be coy too, targeting their reproductive effort towards the most favourable mating opportunities.
The evolutionary ecology of testicular function: size isn’t everything
Ramm SA, Schärer L (2014)
Biological Reviews 89: 874-888. DOI: 10.1111/brv.12084
We review ways in which post-mating sexual selection influences spermatogenesis and testicular function besides via gross testis size.
Comment on “Bateman in Nature: Predation on Offspring Reduces the Potential for Sexual Selection”
Ramm SA, Jonker R, Reinhold K, Szekely T, Trillmich F, Schmoll T, Schielzeth H, Freckleton RP (2013)
Science 340(6132): 549. DOI: 10.1126/science.1233298
A Technical Comment on the application of Bateman gradient analyses to field data.
Baculum morphology predicts reproductive success of male house mice under sexual selection
Stockley P, Ramm SA, Sherborne AL, Thom MDF, Paterson S, Hurst JL (2013)
BMC Biology 11(1): 66. DOI: 10.1186/1741-7007-11-66
First experimental evidence in a mammal that genitalia influence male reproductive success.
Male control of sperm transfer dynamics in a spermatophore-donating bushcricket
Reinhold K, Ramm SA (2013)
Behavioral Ecology and Sociobiology 67(3): 395–398. DOI: 10.1007/s00265-012-1459-4
A reciprocal cross experiment between males and females from two subspecies suggests sperm uptake from the spermatophore is a male-determined trait.
Occurrence, costs and heritability of delayed selfing in a free-living flatworm
Ramm SA, Vizoso DB, Schärer L (2012)
Journal of Evolutionary Biology 25(12): 2559–2568. DOI: 10.1111/jeb.12012
Macrostomum hystrix exhibits delayed selfing behaviour, a reproductive assurance mechanism in the absence of outcrossing opportunities.
Sperm competition roles and ejaculate investment in a promiscuous mammal
Lemaître JF, Ramm SA, Hurst JL, Stockley P (2012)
Journal of Evolutionary Biology 25(6): 1216–1225. DOI: 10.1111/j.1420-9101.2012.02511.x
Contrary to predictions from theory, dominant male bank voles appear competitively superior to subordinates in various post-copulatory traits.
Heterogenous turnover of sperm and seminal vesicle proteins in the mouse revealed by dynamic metabolic labelling
Claydon A, Ramm SA, Penningon A, Hurst JL, Stockley P, Beynon RJ (2012)
Molecular & Cellular Proteomics 11(6): M111.014993. DOI: 10.1074/mcp.m111.014993
We use proteomics techniques to demonstrate the rapid turnover of seminal fluid proteins.
Inbreeding avoidance behaviour of male bank voles in relation to social status
Lemaitre J-F, Ramm SA, Hurst JL, Stockley P (2012)
Animal Behaviour 83(2): 453–457. DOI: 10.1016/j.anbehav.2011.11.017
Male preference for nonsibling females does not vary with social status in male bank voles.
Genital morphology linked to social status in the bank vole (Myodes glareolus)
Lemaitre J-F, Ramm SA, Jennings N, Stockley P (2012)
Behavioral Ecology and Sociobiology 66(1): 97–105. DOI: 10.1007/s00265-011-1257-4
Dominant male bank voles have wider bacula than subordinates, and baculum width exhibits positive allometry.
Social cues of sperm competition influence accessory reproductive gland size in a promiscuous mammal
Lemaitre J-F, Ramm SA, Hurst JL, Stockley P (2011)
Proceedings of The Royal Society B Biological Sciences 278(1709): 1171–1176. DOI: 10.1098/rspb.2010.1828
The first experimental evidence that sperm competition cues affect male investment in seminal fluid production.
Sperm competition and sperm length influence the rate of mammalian spermatogenesis
Ramm SA, Stockley P (2010)
Biology Letters 6(2): 219–221. DOI: 10.1098/rsbl.2009.0635
A comparative study finds that sperm competition and sperm length have significant and opposing effects on the duration of spermatogenesis.
Sexual selection and the rodent baculum: an intraspecific study in the house mouse (Mus musculus domesticus)
Ramm SA, Khoo L, Stockley P (2010)
Genetica 138(1): 129–137. DOI: 10.1007/s10709-009-9385-8
As part of a special issue, we test various indirect predictions of the sexual selection hypothesis for genital evolution.
Sperm competition and brain size evolution in mammals
Lemaitre J-F, Ramm SA, Barton RA, Stockley P (2009)
Journal of Evolutionary Biology 22(11): 2215–2221. DOI: 10.1111/j.1420-9101.2009.01837.x
A negative correlation between brain size and testis size in bats appears not to be a general pattern in other mammals.
Male house mice do not adjust sperm allocation in response to odours from related or unrelated rivals
Ramm SA, Stockley P (2009)
Animal Behaviour 78(3): 685–690. DOI: 10.1016/j.anbehav.2009.06.018
Odour cues from related or unrelated rivals appear not to influence immediate sperm allocation decisions.
Adaptive plasticity of mammalian sperm production in response to social experience
Ramm SA, Stockley P (2009)
Proceedings of The Royal Society B Biological Sciences 276(1657): 745–751. DOI: 10.1098/rspb.2008.1296
We provide the first experimental evidence in a vertebrate that males use sperm competition cues to modify sperm production.
Comparative proteomics reveals evidence for evolutionary diversification of rodent seminal fluid and its functional significance in sperm competition
Ramm SA, McDonald L, Hurst JL, Beynon RJ, Stockley P (2009)
Molecular Biology and Evolution 26(1): 189–198. DOI: 10.1093/molbev/msn237
We show that rodent seminal fluid proteomes are hugely diverse across species, with variation in one key protein linked to sperm competition.
Sexual selection and the adaptive evolution of mammalian ejaculate proteins
Ramm SA, Oliver PL, Ponting CP, Stockley P, Emes RD (2008)
Molecular Biology and Evolution 25(1): 207–219. DOI: 10.1093/molbev/msm242
Evidence for the rapid evolution of reproductive genes and tests for associations with variation in sperm competition levels.
Encoding choosiness: female attraction requires prior physical contact with individual male scents in mice
Ramm SA, Cheetham SA, Hurst JL (2008)
Proceedings of The Royal Society B Biological Sciences 275(1644): 1727–1735. DOI: 10.1098/rspb.2008.0302
We show that female mice are only attracted to airborne urinary volatiles from males whose urine they have previously contacted, implying individual recognition.
Sexual selection and genital evolution in mammals: A phylogenetic analysis of baculum length
Ramm SA (2007)
The American Naturalist 169(3): 360–369. DOI: 10.1086/510688
Comparative evidence that genitalia are under sexual selection in mammals.
Ejaculate allocation under varying sperm competition risk in the house mouse, Mus musculus domesticus
Ramm SA, Stockley P (2007)
Behavioral Ecology 18(2): 491–495. DOI: 10.1093/beheco/arm003
Males surprisingly allocate fewer sperm under conditions simulating an elevated risk of sperm competition, likely due to a correlated response in mating behaviour.
Sperm competition and the evolution of male reproductive anatomy in rodents
Ramm SA, Parker GA, Stockley P (2005)
Proceedings of The Royal Society B Biological Sciences 272(1566): 949–955. DOI: 10.1098/rspb.2004.3048
We find that multiple paternity levels predict relative testis size, and demonstrate correlated evolution of male investment in sperm and seminal fluid production.