Early exposure to hypoxia is related to a variety of physiological and metabolic changes that have lasting effects on organisms’ physiology and life history. We measured the effects of maternal and embryonic mild, intermittent hypoxia on the life history of four clones of microcrustacean Daphnia magna, an emerging model organism for the studies of senescence and longevity. Daphnia individuals were produced parthenogenically, maintained in individual vials, and fed standard algal concentration daily. The cohort consisted of 189 individuals. We measured body size at first reproduction, fecundity (including late-life fecundity peak), offspring sex ratio, and longevity. We found no effect of maternal and embryonic hypoxia on body size and longevity; however, there was a slight but statistically significant increase in age-specific mortality in the early hypoxia treatment cohort. Daphnia from the hypoxia group showed higher early fecundity which disappeared by the age of 100 days. A late-life spike in fecundity was observed at the age of 100 days when hypoxia group individuals showed significantly lower fecundity. There was little evidence of a trade-off between early- and late-life fecundity. Finally, early hypoxia affected mid-life male production in one of the four clones, and we discuss possible physiological changes triggered by maternal and embryonic exposure to hypoxia.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:honors-1839 |
| Date | 01 December 2021 |
| Creators | Lowman, Rachael |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Undergraduate Honors Theses |
| Rights | Copyright by the authors., http://creativecommons.org/licenses/by-nc-nd/3.0/ |
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