Becky Cramer

https://scholar.google.com/citations?user=L27gHbUAAAAJ&hl=en&oi=sra

• Albrecht, Tomas; Opletalová, Kamila; Reif, Jiri; Janousek, Vaclav; Pialek, Lubomir; Cramer, Emily Rebecca A; Johnsen, Arild & Reifova, Radka (2019). Sperm divergence in a passerine contact zone: Indication of reinforcement at the gametic level. Evolution.  ISSN 0014-3820.  73(2), s 202- 213 . doi: 10.1111/evo.13677 Full text in Research Archive.
• Cramer, Emily Rebecca A; Rowe, Melissah; Eroukhmanoff, Fabrice; Lifjeld, Jan Terje; Sætre, Glenn-Peter & Johnsen, Arild (2019). Measuring sperm swimming performance in birds: effects of dilution, suspension medium, mechanical agitation, and sperm number. Journal of Ornithology = Journal fur Ornithologie.  ISSN 0021-8375.  s 1- 11 . doi: 10.1007/s10336-019-01672-9 Full text in Research Archive.
• Sætre, Camilla Lo Cascio; Johnsen, Arild; Stensrud, Even & Cramer, Emily Rebecca A (2018). Sperm morphology, sperm motility and paternity success in the bluethroat (Luscinia svecica). PLOS ONE.  ISSN 1932-6203.  13(3) . doi: 10.1371/journal.pone.0192644 Full text in Research Archive.
• Taugbøl, Annette; Mazzarella, Anna; Cramer, Emily Rebecca A & Laskemoen, Terje (2017). Salinity-induced phenotypic plasticity in threespine stickleback sperm activation. Biology Letters.  ISSN 1744-9561.  13(10), s 1- 4 . doi: 10.1098/rsbl.2017.0516 Full text in Research Archive. Show summary

  Phenotypic expression may be and often is influenced by an organism’s developmental environment, referred to as phenotypic plasticity. The sperm cells of teleosts have been found to be inactive in the seminal plasma and are activated by osmotic shock for most fish species, through release in either hypertonic (for marine fish) or hypotonic (for freshwater fish) water. If this is the case, the regulatory system of sperm mobility should be reversed in salt- and freshwater fish. We tested this hypothesis by first activating sperm of salt- and freshwater populations of threespine stickleback in salt- and freshwater. The sperm from saltwater stickleback could be activated in either salinity, which matches the freshwater colonization history of the species, whereas the sperm from the freshwater population acted as predicted by the osmotic shock theory and was activated in freshwater only. As the freshwater population used here was calculated to be thousands of years old, we went on to test whether the trait(s) were plastic and sperm from freshwater males still could be activated in saltwater after individualswere exposed to saltwater. After raising freshwater stickleback in saltwater, we found the mature males to have active sperm in both saltwater and freshwater. Further, we also found the sperm of wild-caught freshwater stickleback to be active in saltwater after exposing those mature males to saltwater for only 2 days. This illustrates that the ability for stickleback sperm to be activated in a range of water qualities is an environmentally induced plastic trait. adaptive evolution, plasticity, salinity, sperm activation, Gasterosteus aculeatus

• Cramer, Emily Rebecca A; Stensrud, Even; Marthinsen, Gunnhild; Hogner, Silje; Johannessen, Lars Erik; Laskemoen, Terje; Eybert, Marie-Christine; Slagsvold, Tore; Lifjeld, Jan Terje & Johnsen, Arild (2016). Sperm performance in conspecific and heterospecific female fluid. Ecology and Evolution.  ISSN 2045-7758. . doi: 10.1002/ece3.1977 Full text in Research Archive.
• Cramer, Emily Rebecca A; Ålund, Murielle; McFarlane, S. Eryn; Johnsen, Arild & Qvarnström, Anna (2016). Females discriminate against heterospecific sperm in a natural hybrid zone. Evolution.  ISSN 0014-3820.  70(8), s 1844- 1855 . doi: 10.1111/evo.12986
• Eroukhmanoff, Fabrice; Rowe, Melissah; Cramer, Emily Rebecca A; Haas, Fredrik; Hermansen, Jo Skeie; Runemark, Anna; Johnsen, Arild & Sætre, Glenn-Peter (2016). Experimental evidence for ovarian hypofunction in sparrow hybrids. Avian Research.  ISSN 2053-7166.  7 . doi: 10.1186/s40657-016-0038-1
• Cramer, Emily Rebecca A; Laskemoen, Terje; Stensrud, Even; Rowe, Melissah; Haas, Fredrik; Lifjeld, Jan Terje; Sætre, Glenn-Peter & Johnsen, Arild (2015). Morphology-function relationships and repeatability in the sperm of Passer sparrows. Journal of morphology.  ISSN 0362-2525.  276(4), s 370- 377 . doi: 10.1002/jmor.20346
• Rowe, Melissah; Albrecht, Tomas; Cramer, Emily Rebecca A; Johnsen, Arild; Laskemoen, Terje; Weir, Jason T & Lifjeld, Jan Terje (2015). Postcopulatory sexual selection is associated with accelerated evolution of sperm morphology. Evolution.  ISSN 0014-3820.  69(4), s 1044- 1052 . doi: 10.1111/evo.12620
• Cramer, Emily Rebecca A; Laskemoen, Terje; Eroukhmanoff, Fabrice; Haas, Fredrik; Hermansen, Jo Skeie; Lifjeld, Jan Terje; Rowe, Melissah; Sætre, Glenn-Peter & Johnsen, Arild (2014). Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair. Behavioral Ecology and Sociobiology.  ISSN 0340-5443.  68(7), s 1133- 1144 . doi: 10.1007/s00265-014-1724-9
• Cramer, Emily Rebecca A (2013). Measuring consistency: spectrogram cross-correlation versus targeted acoustic parameters. Bioacoustics.  ISSN 0952-4622.  22(3), s 247- 257 . doi: 10.1080/09524622.2013.793616
• Cramer, Emily Rebecca A (2013). Physically Challenging Song Traits, Male Quality, and Reproductive Success in House Wrens. PLOS ONE.  ISSN 1932-6203.  8(3) . doi: 10.1371/journal.pone.0059208
• Cramer, Emily Rebecca A (2013). Vocal deviation and trill consistency do not affect male response to playback in house wrens. Behavioral Ecology.  ISSN 1045-2249.  24(2), s 412- 420 . doi: 10.1093/beheco/ars178
• Cramer, Emily Rebecca A; Laskemoen, Terje; Kleven, Oddmund; LaBarbera, Katie; Lovette, Irby J. & Lifjeld, Jan Terje (2013). No evidence that sperm morphology predicts paternity success in wild hous wrens. Behavioral Ecology and Sociobiology.  ISSN 0340-5443.  67(11), s 1845- 1853 . doi: 10.1007/s00265-013-1594-6
• Cramer, Emily Rebecca A; Laskemoen, Terje; Kleven, Oddmund & Lifjeld, Jan Terje (2013). Sperm length variation in House Wrens Troglodytes aedon. Journal of Ornithology = Journal fur Ornithologie.  ISSN 0021-8375.  154(1), s 129- 138 . doi: 10.1007/s10336-012-0878-3 Show summary

  It is well documented that sperm size and structure varies considerably among avian species, but we know much less about the extent of intraspecific variation in sperm morphometry and its possible co-variation with somatic traits like body size and condition. Here, we investigate patterns of sperm length variation and co-variation in a population of House Wrens (Troglodytes aedon). Total sperm length showed considerable between-male variation, with high repeatability between seasons indicative of a strong genetic basis for this trait. However, we also detected a seasonal increase in the flagellum:head length ratio, which might indicate phenotypic plasticity or adjustment in the relative size of sperm components. The variation in total sperm length within an ejaculate sample was higher for males sampled very early in the season, which may reflect more heterogeneity in the size of seminiferous tubules when testes are growing. None of the studied sperm morphometry traits correlated significantly with any measures of male body size or physiological condition. Further studies are needed to reveal if the observed individual variation in sperm morphology plays any functional or adaptive role. Sperm morphology, Sperm competition, Body condition, House Wren, Seasonality

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• Cramer, Emily Rebecca A (2017). Songbird sperm: the unexplored side of sexual selection.
• Ålund, Murielle; Cramer, Emily Rebecca A; McFarlane, Eryn; Johnsen, Arild & Qvarnström, Anna (2017). Females discriminate against heterospecific sperm in a natural hybrid zone.
• Cramer, Emily Rebecca A (2015). Songs, sperm, and speciation: the role of sexual selection.
• Cramer, Emily Rebecca A; Ålund, Murielle; McFarlane, S. Eryn; Johnsen, Arild & Qvarnström, Anna (2015). A post-copulatory pre-zygotic barrier between collared and pied flycatchers.
• Cramer, Emily Rebecca A (2014). Can sperm evolution facilitate speciation in passerine birds?.
• Cramer, Emily Rebecca A (2014). Sperm biology in passerines: individual variation and evolutionary implications.
• Cramer, Emily Rebecca A; Ålund, Murielle; Laskemoen, Terje; Eroukhmanoff, Fabrice; Eybert, Marie-Christine; Haas, Fredrik; Hermansen, Jo Skeie; Lifjeld, Jan Terje; Rowe, Melissah; Qvarnström, Anna; Sætre, Glenn-Peter & Johnsen, Arild (2014). Post-copulatory, pre-zygotic isolating barriers in passerine birds?.
• Johnsen, Arild; Cramer, Emily Rebecca A & Grydeland, Ivar (2014, 20. august). Fugleforskerne i Heimdalen. [Radio].  Ekko, NRK P2.
• Rowe, Melissah; Albrecht, Tomas; Cramer, Emily Rebecca A; Johnsen, Arild; Laskemoen, Terje; Weir, Jason T & Lifjeld, Jan Terje (2014). Postcopulatory sexual selection accelerates rates of evolutionary divergence in sperm morphology..
• Cramer, Emily Rebecca A (2013). Sperm biology in passerines: individual variation and evolutionary implications.
• Cramer, Emily Rebecca A (2013). The swimmers of singers: sexual selection in birds before and after copulation.
• Cramer, Emily Rebecca A & Johnsen, Arild (2013). Post-mating, pre-zygotic barriers and speciation.
• Cramer, Emily Rebecca A; Laskemoen, Terje; Eroukhmanoff, Fabrice; Haas, Fredrik; Hermansen, Jo Skeie; Lifjeld, Jan Terje; Rowe, Melissah; Sætre, Glenn-Peter & Johnsen, Arild (2013). An experimental test of a potential post-copulatory pre-zygotic reproductive barrier in a passerine species pair.
• Cramer, Emily Rebecca A; Laskemoen, Terje; Eroukhmanoff, Fabrice; Haas, Fredrik; Hermansen, Jo Skeie; Lifjeld, Jan Terje; Rowe, Melissah; Sætre, Glenn-Peter & Johnsen, Arild (2013). Testing a post-copulatory pre-zygotic reproductive barrier in a passerine species pair.

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