Bet hedging and cold-temperature termination of diapause in the life history of the Atlantic salmon ectoparasiteArgulus canadensis
| Autor: | Tyler J. Lynn, Michael S. Duffy, Ji-Won Jeong |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Parasitology. 147:1774-1785 |
| ISSN: | 1469-8161 0031-1820 |
| DOI: | 10.1017/s0031182020001766 |
| Popis: | Argulus canadensisis a crustacean ectoparasite observed increasingly on wild migrating adult Atlantic salmon. We investigated temperature and salinity tolerance regarding development, survival and hatch ofA. canadensiseggs to help understand spatiotemporal features of transmission.Argulus canadensiseggs differentiate to pharate embryos by 35 days buttheir hatch is protracted to ~7 months. Cold treatment ⩾75 days mimics overwintering and terminates egg diapause, with 84.6% (72.1–100%) metanauplius hatch induced ⩾13 °C and synchronized to 3–4 weeks. Inter- and intra-clutch variability and protracted hatch in the absence of cold-temperature termination of diapause is compatible with bet hedging. Whereas diapause likely promotes phenological synchrony for host colocalization, bet hedging could afford temporal plasticity to promote host encounter during environmental change. Our egg storage and hatch induction/synchronization methodologies can be exploited for empirical investigations. Salinity tolerance reveals both significantly higher embryonic development (94.4 ± 3.5%vs61.7 ± 24.6%) and metanauplius hatch (53.3 ± 7.5%vs10.1 ± 8.2%) for eggs in freshwater than at 17 ppt. Unhatched embryos were alive in freshwater by the end of the trial (213 days) but were dead/dying at 17 ppt. Eggs did not develop at 34 ppt. Salinity tolerance ofA. canadensiseggs supports riverine transmission to adult Atlantic salmon during return to freshwater for mating each year. |
| Databáze: | OpenAIRE |
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