Stressed and Hungry: How Does Oxidative Stress Alter Nutrient Choices and Investment Decisions?
Faculty Mentor Name
Zachary Stahlschmidt
Research or Creativity Area
Natural Sciences
Abstract
Many aspects of environmental change–heat waves, droughts, and pollution–induce oxidative stress (OS), which is a physiological stress that can influence survival, reproduction, and dispersal. The costs of OS may be mediated by nutritional decisions, such as resource acquisition (feeding choices) and resource allocation (how ingested nutrients are invested into different tissues). Here, we investigated how OS influences these resource-related decisions in adult female variable field crickets (Gryllus lineaticeps). In the first week of adulthood, long-winged females received three injections of either saline (control) or OS-inducing paraquat (PQ, an herbicide that promotes oxidative damage). Throughout the experiment, crickets chose between high-carbohydrate and high-protein diets. The following were then measured: (1) consumption of calories, protein, and carbohydrate, (2) somatic mass gained as an indicator of self-maintenance, (3) ovary mass gained as an indicator of reproductive investment, and (4) functional status of flight muscle as an indicator of investment into dispersal capacity. We tested competing hypotheses regarding resource (food) acquisition that OS increases preference for consumption of (a) proteins to support antioxidant defenses, or (b) carbohydrates to support energy use (given energetic costs of antioxidant defenses) and/or energy storage (fat). We also tested competing hypotheses regarding resource allocation–specifically, (c) whether resources were invested into current reproduction (ovaries) at an expense to self-maintenance (somatic tissue mass and flight musculature); i.e., ‘terminal reproductive investment’ or (d) vice versa where investment into current reproduction is deprioritized in favor of investment into self-maintenance; i.e.,‘reproductive restraint’. By examining how nutritional choices and OS influence investment strategies, our study helps us understand the mechanisms determining physiological resistance in changing environments.
Stressed and Hungry: How Does Oxidative Stress Alter Nutrient Choices and Investment Decisions?
Many aspects of environmental change–heat waves, droughts, and pollution–induce oxidative stress (OS), which is a physiological stress that can influence survival, reproduction, and dispersal. The costs of OS may be mediated by nutritional decisions, such as resource acquisition (feeding choices) and resource allocation (how ingested nutrients are invested into different tissues). Here, we investigated how OS influences these resource-related decisions in adult female variable field crickets (Gryllus lineaticeps). In the first week of adulthood, long-winged females received three injections of either saline (control) or OS-inducing paraquat (PQ, an herbicide that promotes oxidative damage). Throughout the experiment, crickets chose between high-carbohydrate and high-protein diets. The following were then measured: (1) consumption of calories, protein, and carbohydrate, (2) somatic mass gained as an indicator of self-maintenance, (3) ovary mass gained as an indicator of reproductive investment, and (4) functional status of flight muscle as an indicator of investment into dispersal capacity. We tested competing hypotheses regarding resource (food) acquisition that OS increases preference for consumption of (a) proteins to support antioxidant defenses, or (b) carbohydrates to support energy use (given energetic costs of antioxidant defenses) and/or energy storage (fat). We also tested competing hypotheses regarding resource allocation–specifically, (c) whether resources were invested into current reproduction (ovaries) at an expense to self-maintenance (somatic tissue mass and flight musculature); i.e., ‘terminal reproductive investment’ or (d) vice versa where investment into current reproduction is deprioritized in favor of investment into self-maintenance; i.e.,‘reproductive restraint’. By examining how nutritional choices and OS influence investment strategies, our study helps us understand the mechanisms determining physiological resistance in changing environments.
