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2013-2014 Bayer Fellows

  • Enrica Balboni, CEEES (Burns, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • Matt Cooper, BIOS (Lamberti, Advisor)

    Project Title: Nutrient limitation and uptake of anthropogenic nitrogen in Great Lakes coastal wetlands
    Research Summary: Coastal wetlands are important “hotspots” of productivity and diversity in the Laurentian Great Lakes. These wetlands are critical habitats for many Great Lakes fishes, birds, amphibians, and invertebrates, as well as many rare and threatened plants. Unfortunately, excessive nutrient loading from fertilizer runoff, wastewater effluent, and industrial discharges has severely degraded the ecological health of many Great Lakes coastal wetlands. Despite the conspicuous effects that excessive nutrient loading has in coastal wetlands, there remains little consensus as to which macronutrient—nitrogen (N) or phosphorus (P)—is most responsible for ecological impairment or the degree to which anthropogenic nitrogen gets incorporated into wetland food webs. As a consequence, resource managers are unable to strategically target nutrient sources in their efforts to preserve or restore coastal wetland health. I addressed this information gap by conducting nutrient amendment experiments across a large number of coastal wetlands to determine which nutrient most frequently limits primary productivity and what environmental factors determine nutrient limitation rates. I also used N stable isotope ratios to estimate the proportion of algal N derived from anthropogenic sources.

    Nutrient limitation assays conducted in 66 coastal wetlands of Lakes Michigan and Huron from 2011 to 2013 suggested that autotrophic biofilms (i.e., algae growing on surfaces) were most often limited by N (42% of wetlands) or co-limited by N and P (18%), and rarely limited by P alone (3%). The magnitude of N limitation was negatively correlated with water column dissolved N concentrations and the percentage of watershed land in agriculture or urbanization. These results suggest that autotrophic production in Great Lakes coastal wetlands responds to the amount of N running off the landscape, which is noteworthy because N loading is not managed in the Great Lakes. Since the early 1970’s, nutrient management has focused almost exclusively on P because it is the primary limiting nutrient for offshore primary productivity. Therefore, coastal habitats remain highly vulnerable to N loading and results from this study suggest that managing P alone is not effective when the entire Great Lakes ecosystem is considered. Additionally, the increasing frequency and intensity of heavy precipitation events combined with intensification of urban and agricultural land use, both of which are projected for the coming decades, further support the need for comprehensive nutrient management throughout the Great Lakes basin.

    To track the incorporation of anthropogenic N (e.g., from fertilizer and wastewater) into coastal wetland food webs, I measured biofilm stable N isotope ratios for a subset of wetlands where nutrient amendment experiments were conducted. A detectable signal of elevated δ14 N was found in wetlands that had a high percentage of watershed urbanized land, likely due to the incorporation of wastewater N into algal biofilms. This is broadly consistent with the nutrient amendment results that showed anthropogenic N was ameliorating the natural N-limitation that occurs in Great Lakes coastal wetlands. However, a comparable isotopic signal was not detected in biofilms from wetlands receiving heavy loads of agricultural runoff, likely due to the modest difference in isotopic ratios between fertilizer N and background ambient N.

  • Glen Hood, BIOS (Feder, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • James Radich, BIOS (Kamat, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • A.J. Reisinger, BIOS (Tank, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • Keshia Kuhn, CEEES (Maurice, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • Qiang Yu, CEEES (Fein, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • Greg Nuemann, CBE (Hicks, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.

  • James Zokoe, CBE (McGinn, Advisor)

    Project Title: The evolution of reproductive isolation and speciation in Rhagoletis: determining the role of cuticular hydrocarbon divergence.
    In insects, the exchange of species–specific chemical, auditory and visual cues during courtship is critical for reproduction. If cues differ between species or populations, they may serve as a premating barrier to gene flow. What environmental variables influence sensory cues in insects? One of the most well-studied is cuticular hydrocarbon (CHC) divergence. CHCs serve as contact pheromones during courtship preceding copulation. Some CHCs serve as attractants while others deter contact. In plant feeding insects, both the type and quantity of CHCs in adults are typically controlled by the substrate fed upon by developing larvae. While a Bayer fellow at CEST, I was able to investigate the role of CHC divergence between diverging populations and species of fruit flies in the genus Rhagoletis.