Reproduction in the brine shrimp Artemia: evolutionary relevance of laboratory cross-fertility tests
Gajardo, G.; Parraguéz, M.; Beardmore, J.A.; Sorgeloos, P. (2001). Reproduction in the brine shrimp Artemia: evolutionary relevance of laboratory cross-fertility tests. J. Zool. (1987) 253(1): 25-32. http://dx.doi.org/10.1017/S0952836901000036 In: Journal of Zoology. Zoological Society of London: London. ISSN 0952-8369; e-ISSN 1469-7998, more |  |
| Keywords | Biological phenomena > Encystment
Biological phenomena > Evolution
Fertility
Hybrids
Properties > Biological properties > Fecundity
Reproduction
Argentina Linnaeus, 1758 [WoRMS]; Artemia Leach, 1819 [WoRMS]; Artemia franciscana Kellog, 1906 [WoRMS]
Argentina, Buenos Aires [Marine Regions]; Chile [Marine Regions]; Indo-Pacific North East [Marine Regions]; PSW, Argentina, Buenos Aires [Marine Regions]
Marine/Coastal; Brackish water | | Author keywords | Artemia; life history; reproductive output; cross-fertility tests;interpopulational differentiation |
| Authors | | Top | - Gajardo, G.
- Parraguéz, M.
- Beardmore, J.A.
- Sorgeloos, P., more
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| Abstract | The brine shrimp Artemia , a typical inhabitant of hypersaline environments and characterized by a highly subdivided population structure, was used as a model to evaluate, under standardized laboratory conditions (at 65 ppt), primary reproductive traits (offspring quality and quantity) along with levels of reproductive isolation and degrees of divergence among populations. Intrapopulation experimental crosses and cross-fertility tests were evaluated in five populations (mostly A. franciscana) from coastal and inland environments in Chile, and in reference samples of A. franciscana (San Francisco Bay, USA) and A. persimilis (Buenos Aires, Argentina), which are the species likely to be found in Chile. The populations compared displayed significant variability in fecundity (total offspring, brood size) as well as in the ratio encystment/oviviparity. Hybrid offspring, produced abundantly in cross-fertility tests with reference populations, showed a pronounced switch to the encystment mode, particularly in crosses with A. persimilis. Exposure to a broad range of ecological conditions seems to have optimized a generalist reproductive strategy in the Artemia populations studied that combines variation in both the quantity and quality of zygotes. Laboratory cross-fertility tests evaluated prime reproductive characteristics in individual crosses with fair repeatability, as well as testing barriers to laboratory reproductive isolation. The lack of efficient mechanisms for reproductive isolation in the allopatric Artemia populations studied follows a trend often seen in other anostracods. Formerly allopatric populations have not achieved sympatry later as required by the allopatric speciation paradigm, and this is a probable explanation for production of the laboratory hybrids. |
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