When the tap runs dry: The physiological effects of acute experimental dehydration inPeromyscus eremicus

Abstract

Desert organisms have evolved physiological, biochemical, and genomic mechanisms to survive the extreme aridity of desert environments. Studying desert-adapted species provides a unique opportunity to investigate the survival strategies employed by organisms in some of the harshest habitats on Earth. Two of the primary challenges faced in desert environments are maintaining water balance and thermoregulation. We collected data in a simulated desert environment and a captive colony of cactus mice (Peromyscus eremicus) and used lab-based experiments with real time physiological measurements to characterize the response to water-deprivation. Mice without access to water had significantly lower energy expenditures and in turn, reduced water loss compared to mice with access to water after the first 24 hours of the experiment. Additionally, we observed significant weight loss likely related to dehydration-associated anorexia a response to limit fluid loss by reducing waste and the solute load as well as allowing water reabsorption from the kidneys and gastrointestinal tract. Finally, we observed body temperature correlated with sex, with males without access to water maintaining body temperature when compared to hydrated males while body temperature decreased for females without access to water compared to hydrated, suggesting daily torpor in females.

Impacts of dietary fat on multi tissue gene expression in the desert-adapted cactus mouse

“…Following the methods in Blumstein and MacManes (2024), we cross-referenced our gene IDs with Homo sapiens gene IDs and filtered low expression genes, leaving 17012 genes in the dataset as a whole. Patterns of gene expression data are largely driven by tissue type (PC1: 44% variance and PC2: 23% variance, Supplemental Figure 1).…”

“…Following similar methods to Blumstein and MacManes (2024), the lung, liver, kidney, a section of the GI tract, and hypothalamus were collected, preserved, and RNA was extracted from anatomically similar regions of the tissue using a standardized Trizol protocol. RNAseq libraries were prepped for sequencing using a poly-A tail purification, barcoded using Illumina primers, and dual-barcoded using a New England Biolabs Ultra II Directional kit (NEB #E7765).…”

“…Harsh environments (e.g., high altitude, deep sea, deserts) represent natural experiments, given that organisms living in these extreme environments have evolved physiological, biochemical, and genomic mechanisms to persist (Blumstein and MacManes, 2023; Blumstein and MacManes, 2024; Kordonowy et al, 2017; Tigano et al, 2022; Wilsterman and Cheviron, 2021). One way for organisms survive under extreme conditions is to carefully manage their intake of food by making strategic decision based on environmental conditions which include food availability.…”

“…As the planet continues to undergo unprecedented climate change, increased desertification and a decrease in free water availability is predicted (IPCC, 2019; Mirzabaev et al, 2019). Several studies have demonstrated or predicted distributional changes in extant species in response to changing climate (Moritz et al, 2008; Parmesan, 2006), but fewer have examined the physiological (Bijlsma and Loeschcke, 2005; Blumstein and MacManes, 2023; Blumstein et al, 2024; Gabriel, 2005; Ramirez et al, 2022) and genomic (Blumstein and MacManes, 2024; Cheviron et al, 2014; Colella et al, 2021; MacManes, 2017; Tigano et al, 2020) mechanisms that may allow animals to adapt in place.…”

“…During water deprivation, animals have been observed reduce solid food intake, a phenomenon known as dehydration-associated anorexia, which minimizes water needed for digestion and allows for water reabsorption from the kidneys and gastrointestinal tract (Armstrong et al, 1980; Blumstein and MacManes, 2024; Hamilton and Flaherty, 1973; Rowland, 2007; Salter and Watts, 2003; Schoorlemmer and Evered, 2002; Watts and Boyle, 2010). Glucose levels are maintained during limited food intake and water deprivation due to enhanced glycogenolysis and gluconeogenesis (Blumstein and MacManes, 2024; Salter and Watts, 2003; Schoorlemmer and Evered, 2002; Watts and Boyle, 2010). The inhibition of glycolysis impedes glucose metabolism (Spriet, 2014).…”