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Redinger JM, Halvorson HM, Gifford ME. Variable stoichiometric and macronutrient responses to lizard predation in Ozark glade grasshopper communities. Oecologia 2022; 199:757-768. [PMID: 35610326 DOI: 10.1007/s00442-022-05185-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
The General Stress Paradigm (GSP) predicts that prey body compositions should shift under chronic predation as prey increase body carbon and decrease body nitrogen content through dietary changes, heightened metabolism, reduced dietary efficiency, and the breakdown of nitrogen rich tissues to make labile carbohydrates available. In our study, we explored how the elemental and macronutrient content along with the morphology of three abundant Ozark glade grasshopper species differed between glades with and without predatory collared lizard (Crotaphytus collaris) populations. Our results indicated that lichen grasshoppers (Trimerotropis saxatilis) increased body C:N ratios in response to predators. Scudder's short-wing grasshoppers (Melanoplus scudderi) increased both body %C and %protein content, while the handsome grasshoppers (Syrbula admirabilis) did not significantly respond to the presence of collared lizards. None of the three grasshopper species showed morphological responses to predation. We also found that elemental and macronutrient content of grasshoppers was not always significantly correlated and was not associated with the same environmental factors, indicating a need to incorporate both perspectives in future research and utilize more accurate macromolecular assays. Overall, we found support for some aspects of the GSP in field-active animals and add to the growing body of evidence that predator-induced changes in prey body composition are more complex than predicted by the original GSP.
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Affiliation(s)
- Joseph M Redinger
- Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA
| | - Halvor M Halvorson
- Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA
| | - Matthew E Gifford
- Department of Biology, University of Central Arkansas, Conway, AR, 72035, USA.
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Warne RW, Wolf BO. Nitrogen stable isotope turnover and discrimination in lizards. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9030. [PMID: 33332668 DOI: 10.1002/rcm.9030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/16/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
RATIONALE Nitrogen stable isotope ratio (δ15 N) processes are not well described in reptiles, which limits reliable inference of trophic and nutrient dynamics. In this study we detailed δ15 N turnover and discrimination (Δ15 N) in diverse tissues of two lizard species, and compared these results with previously published carbon data (δ13 C) to inform estimates of reptilian foraging ecology and nutrient physiology. METHODS We quantified 15 N incorporation and discrimination dynamics over 360 days in blood fractions, skin, muscle, and liver of Sceloporus undulatus and Crotaphytus collaris that differed in body mass. Tissue samples were analyzed on a continuous flow isotope ratio mass spectrometer. RESULTS Δ15 N for plasma and red blood cells (RBCs) ranged between +2.7 and +3.5‰; however, skin, muscle, and liver did not equilibrate, hindering estimates for these somatic tissues. 15 N turnover in plasma and RBCs ranged from 20.7 ± 4 to 303 ± 166 days among both species. Comparison with previously published δ13 C results for these same samples showed that 15 N and 13 C incorporation patterns were uncoupled, especially during winter when hibernation physiology could have played a role. CONCLUSIONS Our results provide estimates of 15 N turnover rates and discrimination values that are essential to using and interpreting isotopes in studies of diet reconstruction, nutrient allocation, and trophic characterization in reptiles. These results also suggest that somatic tissues can be unreliable, while life history shifts in nutrient routing and metabolism potentially cause 15 N and 13 C dynamics to be decoupled.
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Affiliation(s)
- Robin W Warne
- School of Biological Sciences, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Blair O Wolf
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
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Ouyang MY, Liu JH, Wen B, Huang JN, Feng XS, Gao JZ, Chen ZZ. Ecological stoichiometric and stable isotopic responses to microplastics are modified by food conditions in koi carp. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124121. [PMID: 33011633 DOI: 10.1016/j.jhazmat.2020.124121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/18/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
Microplastics (MPs) can be easily taken up by a wide range of aquatic animals and cause blockage of the digestive tract leading to starvation. Meanwhile, aquatic organisms are facing threats posed by food restriction in both wild and cultured environment. Little knowledge, however, exists on how MPs interact with food conditions to affect aquatic animals. Here, koi carp were exposed to polystyrene MPs (0, 100 or 1000 μg/L) under controlled feeding (satiated or starved) for 30 or 60 days. MPs reduced and interacted synergistically with food conditions on growth after 30 days but antagonistically after 60 days. MPs reduced crude lipid and carbohydrate but increased and antagonistically interacted with feeding conditions on crude protein. Food conditions interacted with MPs on C, N and P but stoichiometric responses were decoupled with macromolecules changes. Food conditions antagonistically interacted with MPs on δ13C after 60 days. Linear discriminant analysis revealed that C:P and N:P were the two most important measured parameters accounting for the response of koi towards MPs and food restriction, presenting an antagonistic interaction of MPs and food status with the prolonged exposure duration.
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Affiliation(s)
- Ming-Yan Ouyang
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China
| | - Jun-Heng Liu
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China
| | - Bin Wen
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
| | - Jun-Nan Huang
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China
| | - Xiao-Sa Feng
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China
| | - Jian-Zhong Gao
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China
| | - Zai-Zhong Chen
- National Demonstration Centre for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Centre of Aquaculture, Shanghai Ocean University, Shanghai 201306, China.
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Rinehart S, Hawlena D. The effects of predation risk on prey stoichiometry: a meta‐analysis. Ecology 2020; 101:e03037. [DOI: 10.1002/ecy.3037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/03/2019] [Accepted: 01/29/2020] [Indexed: 12/29/2022]
Affiliation(s)
- S. Rinehart
- Department of Ecology, Evolution, and Behavior Alexander Silberman Institute of Life Sciences The Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - D. Hawlena
- Department of Ecology, Evolution, and Behavior Alexander Silberman Institute of Life Sciences The Hebrew University of Jerusalem Jerusalem 91904 Israel
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Kirschman LJ, McCue MD, Boyles JG, Warne RW. Exogenous stress hormones alter energetic and nutrient costs of development and metamorphosis. J Exp Biol 2017; 220:3391-3397. [DOI: 10.1242/jeb.164830] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/17/2017] [Indexed: 11/20/2022]
Abstract
Variation in environmental conditions during larval life stages can shape development during critical windows and have lasting effects on the adult organism. Changes in larval developmental rates in response to environmental conditions, for example, can trade-off with growth to determine body size and condition at metamorphosis, which can affect adult survival and fecundity. However, it is unclear how use of energy and nutrients shape trade-offs across life stage transitions because no studies have quantified these costs of larval development and metamorphosis. We used an experimental approach to manipulate physiological stress in larval amphibians, along with respirometry and 13C-breath testing to quantify the energetic and nutritional costs of development and metamorphosis. Central to larval developmental responses to environmental conditions is the hypothalamus pituitary-adrenal/interrenal (HPA/I) axis, which regulates development, as well as energy homeostasis and stress responses across many taxa. Given these pleiotropic effects of HPA/I activity, manipulation of the HPA/I may provide insight into costs of metamorphosis. We measured the energetic and nutritional costs across the entire larval period and metamorphosis in a larval amphibian exposed to exogenous glucocorticoid (GC) hormones- the primary hormone secreted by the HPA/I axis. We measured metabolic rates and dry mass across larval ontogeny, and quantified lipid stores and nutrient oxidation via 13C-breath testing during metamorphosis, under control and GC-exposed conditions. Changes in dry mass match metamorphic states previously reported in the literature, but dynamics of metabolism were influenced by the transition from aquatic to terrestrial respiration. GC-treated larvae had lower dry mass, fat stores, and higher oxygen consumption during stages where controls were conserving energy. GC-treated larvae also oxidized greater amounts of 13C-labelled protein stores. These results provide evidence for a proximate cause of the physiological trade-off between larval growth and development, and provide insight into the energetic and nutrient costs that shape fitness trade-offs across life stages.
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Affiliation(s)
- Lucas J. Kirschman
- Department of Zoology, Southern Illinois University, Carbondale, IL USA, 62901
| | - Marshall D. McCue
- Department of Biological Sciences, St. Mary's University, San Antonio, TX, 78228, USA
| | - Justin G. Boyles
- Cooperative Wildlife Research Laboratory, Department of Zoology, Southern Illinois University, Carbondale, IL USA, 62901
| | - Robin W. Warne
- Department of Zoology, Southern Illinois University, Carbondale, IL USA, 62901
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