Causes and consequences of trade-offs across the life cycle
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Many plants and animals face drastically different, often directly opposing, selective pressures as they transition from one life stage to the next, and must optimize development to meet competing demands of each. As a consequence, trade-offs between life stages potentially represent a fundamental constraint on adaptive evolution. My research in this area primarily focuses on 1) what phenotypic and selective factors underlie this conflict between life stages, and 2) how does the ensuing conflict between life stages constrain and/or guide patterns of phenotypic evolution. One system that I use to understand these patterns is the melanin-synthesis pathway in dragonflies. Melanin is used in the production of sexually selected wing coloration and is central to the invertebrate immune system, setting the stage for potential trade-offs within and across life stages. My work examines how the larval environment influences the expression of the melanin-synthesis pathway, as well as how natural selection within each life stage shapes the evolution of the metabolic pathway overall. Additionally, my ongoing collaboration with my Master's advisor, Dr. Howard Whiteman, on life-cycle expression in facultatively paedomorphic salamanders has broad and exciting implications for the evolution of phenotypes linked across the life cycle. Related Publications: Moore & Martin 2018, Oecologia; Moore et al. 2018, J. Evol. Biol. |
Clockwise: Blue dasher (Pachydiplax longipennis) larva; a piece of nylon monofilament (typically clear) covered in melanin produced by the insect immune system; P. longipennis male uniquely marked with acrylic paint for observations; P. longipennis wing ornaments.
Left: Adult morphs (metamorph, top; paedomorph, bottom) of the Arizona tiger salamander (Ambystoma tigrinum nebulosum) expressed in response to the larval environment. Photo credit: Howard Whiteman. Right: Pond 1 at the Mexican Cut Nature Preserve, where a population of these polymorphic salamanders has been the subject of study since before I was born.
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Patterns and Payoffs of Maternal Investment
Top: A female, paedomorphic salamander (Ambystoma talpoideum). Bottom: Experimental pond array at the Hancock Biological Station used for studying the fitness consequences of variation in maternal investment. Photo credit: Tobias Landberg
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Females often exhibit substantial intraspecific variation in the size and number of offspring that they produce, with subsequent fitness consequences for both the mothers and offspring. While earlier studies assumed that the effects of this variation primarily manifest only in the earliest life stages of offspring, we are increasingly recognizing that maternal investment affects offspring traits throughout ontogeny. My research seeks to understand how natural selection acts on maternal investment throughout offspring development, and how this fitness variation ultimately shapes the evolution of maternal investment strategies. To answer some of my general questions about the intrinsic and extrinsic factors shaping this life-history variation, I have worked on a variety of organisms, including salamanders, dart frogs, and livebearing fish. Related Publications: Moore et al. 2015, Ecology; Moore et al. 2016, Ecol. Lett.; Dugas et al. 2016, J. Evol. Biol. |
Ecological interactions and natural selection
Two hypothetical fitness landscapes that illustrate how the optimal phenotype combinations may vary between two environments
Clockwise: Experimental pool used for manipulating agents of selection; Array of pools at the Case Western Reserve University's Squire Valleevue Farm; ultimate instar P. longipennis larva, penultimate instar P. longipennis larva
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Environmental variation changes the strength, form, direction, and targets of natural selection, which ultimately leads to the tremendous diversification that we observe across populations and species. However, we know relatively little about how different ecological interactions actually alter natural selection, limiting our understanding of how the environment directly shapes phenotypic diversity.
In collaboration with my Ph.D. advisor, Dr. Ryan Martin, I use a combination of field, experimental, and meta-analytic techniques to examine how environmental variation alters patterns of natural selection, and what the consequences are for diversification. I am especially interested in evaluating how interactions between putative agents of selection influence the strength, form and direction of natural selection. Related Publications: Moore et al. 2016, Ecol. Lett.; Moore & Martin 2018, Oecologia; Moore et al. 2019, Ecol. Lett. |
