ArticleProceedings. Biological sciences2009
Sperm morphology and sperm velocity in passerine birds.
Article in Proceedings. Biological sciences, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 82 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
82 citing papers in PubMed, 1 synthesis or guideline pooled it.
- How sperm competition shapes the evolution of testes and sperm: a meta-analysis.Philosophical transactions of the Royal Society of London. Series B, Biological sciences · 2020Pooled it
- Are we truly helping those in need: A comprehensive assessment of semen technologies in wild bird species.Biodiversity and conservation · 2026Article
- Relative testis size is associated with vagina length but not sperm storage traits in Galliformes.Evolution letters · 2025Article
- Sperm mtDNA Copy Number Is Not Associated With Midpiece Size Among Songbirds.Ecology and evolution · 2025Article
- Semen collection, semen analysis and artificial insemination in the kākāpō (Strigops habroptilus) to support its conservation.PloS one · 2025Article
- The ancient and helical architecture of Elasmobranchii's spermatozoa enables progressive motility in viscous environments.PloS one · 2025Article
- Post-copulatory competition in a social monogamy system: Sperm morphology correlates with components of reproductive success.PloS one · 2025Article
- Article
- Tetrapod sperm length evolution in relation to body mass is shaped by multiple trade-offs.Nature communications · 2024Article
- Differences in sperm morphology between Alouatta palliata and Alouatta pigra are consistent with the intensity of sperm competition in each species.American journal of primatology · 2023Article
- Sexual selection drives the coevolution of male and female reproductive traits in Peromyscus mice.Journal of evolutionary biology · 2023Article
- Characterization of sperm and implications for male fertility in the last of the Rhynchocephalians.Conservation physiology · 2023Article
- On the Origin and Evolution of Sperm Cells.Cells · 2022Article
- Flagellum tapering and midpiece volume in songbird spermatozoa.Journal of morphology · 2022Article
- Fertilization modes and the evolution of sperm characteristics in marine fishes: Paired comparisons of externally and internally fertilizing species.Ecology and evolution · 2022Article
- Motility Assessment of Ram Spermatozoa.Biology · 2022Review
- Sperm tendency to agglutinate in motile bundles in relation to sperm competition and fertility duration in chickens.Scientific reports · 2022Article
- Article
- Sperm competition in yellow dung flies: No consistent effect of sperm size.Journal of evolutionary biology · 2022Article
- Energy Metabolism and Hyperactivation of Spermatozoa from Three Mouse Species under Capacitating Conditions.Cells · 2022Article
22 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Sperm velocity is one of the main determinants of the outcome of sperm competition. Since sperm vary considerably in their morphology between and within species, it seems likely that sperm morphology is associated with sperm velocity. Theory predicts that sperm velocity may be increased by enlarged midpiece (energetic component) or flagellum length (kinetic component), or by particular ratios between sperm components, such as between flagellum length and head size. However, such associations have rarely been found in empirical studies. In a comparative framework in passerine birds, we tested these theoretical predictions both across a wide range of species and within a single family, the New World blackbirds (Icteridae). In both study groups, sperm velocity was influenced by sperm morphology in the predicted direction. Consistent with theoretical models, these results show that selection on sperm morphology and velocity are likely to be concomitant evolutionary forces.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.