title: Grasshoppers regulate N:p stoichiometric homeostasis by changing phosphorus contents in their frass.
abstract: Nitrogen (N) and phosphorus (P) are important limiting nutrients for plant production and consumer performance in a variety of ecosystems. As a result, the N:P stoichiometry of herbivores has received increased attention in ecology. However, the mechanisms by which herbivores maintain N:P stoichiometric homeostasis are poorly understood. Here, using a field manipulation experiment we show that the grasshopper Oedaleus asiaticus maintains strong N:P stoichiometric homeostasis regardless of whether grasshoppers were reared at low or high density. Grasshoppers maintained homeostasis by increasing P excretion when eating plants with higher P contents. However, while grasshoppers also maintained constant body N contents, we found no changes in N excretion in response to changing plant N content over the range measured. These results suggest that O. asiaticus maintains P homeostasis primarily by changing P absorption and excretion rates, but that other mechanisms may be more important for regulating N homeostasis. Our findings improve our understanding of consumer-driven P recycling and may help in understanding the factors affecting plant-herbivore interactions and ecosystem processes in grasslands.
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Zijia
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America.
authors.forename: James J
authors.initials: JJ
authors.lastname: Elser
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America; School of Biological Sciences, The University of Sydney, Sydney, Australia.
authors.forename: Arianne J
authors.initials: AJ
authors.lastname: Cease
authors.affiliation: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Ximei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China; Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, United States of America.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China; State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
authors.forename: Xingguo
authors.initials: X
authors.lastname: Han
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D049628:Body Size; D005243:Feces / Q000737:chemistry*; D005260:Female; D006110:Grasshoppers / Q000378:metabolism*; D006706:Homeostasis; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010944:Plants / Q000378:metabolism
chemical_list: D010758:Phosphorus; D009584:Nitrogen
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