Influence of genetics and environment on reproductive fitness: lessons from a self-fertilizing, amphibious fish
LE3 .A278 2021
Bachelor of Science
The amphibious mangrove rivulus (Kryptolebias marmoratus) are one of only two self-fertilizing, hermaphroditic vertebrates. Rivulus live in mangroves and have the capability of living both in and out of water and surviving a wide range of environmental conditions. We know the basics of the unique reproductive strategy of rivulus; however, there are still many questions that are worthy of investigation in order to better understand the biology of K. marmoratus and its complex life history.The goal of my thesis was to use three highly homozygous lineages to determine how specific extrinsic and intrinsic factors affect the reproductive fitness of rivulus. To this end, I used four years of reproductive datato determine if rivulus have periods of reproductive highs and lows. In a lab- based study, I gave rivulus the choice between land or water to determine egg-laying preference and reproductive fitness. I observed differences in egg production over time in all 3 lineages. These temporal differences were not seasonally dependent and all lineages preferred to lay eggs in water. There were significant differences between individual fecundity and fitness where some individuals and some lineages laid many eggs but had low hatch success, and some laid fewer eggs but had high hatch success. My research on this emerging model fish provides broad insight into the consequences of genetics and environment on reproductive fitness and is also important for rivulus conservation in the wild and for breeding in the lab. Mangroves are critical yet threatened habitats and we need to understand the environmental challenges for their inhabitants.
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