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A novel sperm adaptation to evolutionary constraints on reproduction: Pre‐ejaculatory sperm activation in the beach spawning capelin (Osmeridae)
- Source :
- Ecology and Evolution, Ecology and Evolution, Vol 8, Iss 4, Pp 2343-2349 (2018)
- Publication Year :
- 2018
- Publisher :
- John Wiley and Sons Inc., 2018.
-
Abstract
- Reproduction of external fertilizing vertebrates is typically constrained to either fresh or salt water, not both. For all studied amphibians and fishes, this constraint includes immotile sperm that are activated after ejaculation only by the specific chemistry of the fertilizing medium in which the species evolved (fresh, brackish, or salt water). No amphibians can reproduce in the sea. Although diadromous fishes may migrate between salt and fresh water, they are shackled to their natal environment for spawning in part because of sperm activation. Here, we report for the first time among all documented external fertilizing vertebrates, that in the absence of any external media, sperm are motile at ejaculation in a marine spawning fish (Osmeridae, capelin, Mallotus villosus). To illuminate why, we evaluated sperm behavior at different salinities in M. villosus as well as the related freshwater spawning anadromous rainbow smelt (Osmerus mordax). Surprisingly, sperm performance was superior in fresh water for both species. M. villosus spend their entire life at sea but our results show that their sperm are deactivated by sea water, suggesting a freshwater ancestry. By circumventing constraining water chemistry, we interpret the unique pre‐ejaculatory sperm activation in this species as a novel adaptation that enables fertilization in the marine environment. These findings also contribute to understanding the persistence of anadromy, despite great energetic costs to adult fishes.
- Subjects :
- 0106 biological sciences
Osmerus
media_common.quotation_subject
Zoology
adaptation
010603 evolutionary biology
01 natural sciences
Rainbow smelt
capelin
evolutionary constraint
14. Life underwater
QH540-549.5
Ecology, Evolution, Behavior and Systematics
reproductive and urinary physiology
Nature and Landscape Conservation
media_common
Original Research
Fish migration
Ecology
biology
Brackish water
urogenital system
010604 marine biology & hydrobiology
Capelin
biology.organism_classification
Sperm
6. Clean water
fertilization
Reproduction
Adaptation
Osmeridae
sperm biology
Subjects
Details
- Language :
- English
- ISSN :
- 20457758
- Volume :
- 8
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Ecology and Evolution
- Accession number :
- edsair.doi.dedup.....b1b96c35edd32ec6ba71fbe27e99ebb9