ArticleJournal of evolutionary biology2019
Sperm morphology and evidence for sperm competition among parrots.
Article in Journal of evolutionary biology, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
What it found
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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.
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Who cites it
6 citing papers in PubMed, 17 citations in OpenAlex.
- Semen collection, semen analysis and artificial insemination in the kākāpō (Strigops habroptilus) to support its conservation.PloS one · 2025Article
- Hidden impacts of conservation management on fertility of the critically endangered kākāpō.PeerJ · 2023Article
- Resurrecting biodiversity: advanced assisted reproductive technologies and biobanking.Reproduction & fertility · 2022Review
- Genomic Evidence for Sensorial Adaptations to a Nocturnal Predatory Lifestyle in Owls.Genome biology and evolution · 2020Article
- Sperm morphology and evidence for sperm competition among parrots.Journal of evolutionary biology · 2019Article
- Postcopulatory sexual selection is associated with sperm aggregate quality inBehavioral ecology : official journal of the International Society for Behavioral EcologyArticle
Corrections and comments
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Authors and funding
7 authors at 3 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Sperm competition is an important component of post-copulatory sexual selection that has shaped the evolution of sperm morphology. Previous studies have reported that sperm competition has a concurrently directional and stabilizing effect on sperm size. For example, bird species that show higher levels of extrapair paternity and larger testes (proxies for the intensity of sperm competition) have longer sperm and lower coefficients of variation in sperm length, both within and between males. For this reason, these sperm traits have been proposed as indexes to estimate the level of sperm competition in species for which other measures are not available. The relationship between sperm competition and sperm morphology has been explored mostly for bird species that breed in temperate zones, with the main focus on passerine birds. We measured sperm morphology in 62 parrot species that breed mainly in the tropics and related variation in sperm length to life-history traits potentially indicative of the level of sperm competition. We showed that sperm length negatively correlated with the within-male coefficient of variation in sperm length and positively with testes mass. We also showed that sperm is longer in sexually dichromatic and in gregarious species. Our results support the general validity of the hypothesis that sperm competition drives variation in sperm morphology. Our analyses suggest that post-copulatory sexual selection is also important in tropical species, with more intense sperm competition among sexually dichromatic species and among species that breed at higher densities.
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