Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment

Abstract Animal populations must be able to acquire an adequate amount of nutrients to persist regardless of what environment they are in. In highly variable environments, such as drylands where food sources are limited, this potential mismatch between physiological demands and what is available in...

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Main Authors: Douglas Lawton, Marion Le Gall, Cathy Waters, Arianne J. Cease
Format: Article
Language:English
Published: Wiley 2021-03-01
Series:Ecosphere
Subjects:
Online Access:https://doi.org/10.1002/ecs2.3409
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author Douglas Lawton
Marion Le Gall
Cathy Waters
Arianne J. Cease
author_facet Douglas Lawton
Marion Le Gall
Cathy Waters
Arianne J. Cease
author_sort Douglas Lawton
collection DOAJ
description Abstract Animal populations must be able to acquire an adequate amount of nutrients to persist regardless of what environment they are in. In highly variable environments, such as drylands where food sources are limited, this potential mismatch between physiological demands and what is available in the environment is accentuated. For herbivores, the balance of macronutrients (protein and carbohydrate) is particularly important and both nutrients are highly variable in plants both spatially and temporally. Whereas it is known that many herbivores will forage multiple plants to achieve an optimal nutritional ratio (termed the intake target), it is less known how herbivores with different life history strategies address this in variable environments. In this study, we measured the intake targets of three grasshopper species with differing life history strategies, two migratory and one non‐migratory, at three locations in New South Wales, Australia. We measured nutrient variation in plants spatially and temporally by sampling three different locations and repeated the measurement twice for one of these locations. At all three locations and both times, host plant protein differed substantially but carbohydrate content remained constant. The non‐migratory grasshopper species shifted their intake target, presumably to redress nutrient imbalances. On the other hand, the two migratory grasshopper species largely maintained the same intake target, even when in a nutritionally suboptimal environment. These results suggest that non‐migratory species are likely more limited in their capacity to forage for optimal diets and may rely more on digestion to survive in nutritionally suboptimal locations. In contrast, migratory grasshoppers may migrate to obtain the nutrients they need instead of redressing imbalances locally. Therefore, a strong metapopulation structure may aid in the persistence of migratory species at larger spatial scales. Since herbivores, especially insects, are important from nutrient cycling to food chains, understanding how populations persist in nutritionally variable environments is important to the overall ecosystem functioning. Further research should consider how nutritional demands drive population dynamics and how it changes with life history strategies.
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spelling doaj.art-655515dfadb84ba7aaa6a64868c007512022-12-21T17:21:52ZengWileyEcosphere2150-89252021-03-01123n/an/a10.1002/ecs2.3409Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environmentDouglas Lawton0Marion Le Gall1Cathy Waters2Arianne J. Cease3School of Life Sciences Arizona State University Tempe Arizona85281USASchool of Sustainability Arizona State University Tempe Arizona85281USASchool of Sustainability Arizona State University Tempe Arizona85281USASchool of Life Sciences Arizona State University Tempe Arizona85281USAAbstract Animal populations must be able to acquire an adequate amount of nutrients to persist regardless of what environment they are in. In highly variable environments, such as drylands where food sources are limited, this potential mismatch between physiological demands and what is available in the environment is accentuated. For herbivores, the balance of macronutrients (protein and carbohydrate) is particularly important and both nutrients are highly variable in plants both spatially and temporally. Whereas it is known that many herbivores will forage multiple plants to achieve an optimal nutritional ratio (termed the intake target), it is less known how herbivores with different life history strategies address this in variable environments. In this study, we measured the intake targets of three grasshopper species with differing life history strategies, two migratory and one non‐migratory, at three locations in New South Wales, Australia. We measured nutrient variation in plants spatially and temporally by sampling three different locations and repeated the measurement twice for one of these locations. At all three locations and both times, host plant protein differed substantially but carbohydrate content remained constant. The non‐migratory grasshopper species shifted their intake target, presumably to redress nutrient imbalances. On the other hand, the two migratory grasshopper species largely maintained the same intake target, even when in a nutritionally suboptimal environment. These results suggest that non‐migratory species are likely more limited in their capacity to forage for optimal diets and may rely more on digestion to survive in nutritionally suboptimal locations. In contrast, migratory grasshoppers may migrate to obtain the nutrients they need instead of redressing imbalances locally. Therefore, a strong metapopulation structure may aid in the persistence of migratory species at larger spatial scales. Since herbivores, especially insects, are important from nutrient cycling to food chains, understanding how populations persist in nutritionally variable environments is important to the overall ecosystem functioning. Further research should consider how nutritional demands drive population dynamics and how it changes with life history strategies.https://doi.org/10.1002/ecs2.3409AcrididaeAustraliadrylandsgrasshoppersinsect herbivorynutritional ecology
spellingShingle Douglas Lawton
Marion Le Gall
Cathy Waters
Arianne J. Cease
Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
Ecosphere
Acrididae
Australia
drylands
grasshoppers
insect herbivory
nutritional ecology
title Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
title_full Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
title_fullStr Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
title_full_unstemmed Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
title_short Mismatched diets: defining the nutritional landscape of grasshopper communities in a variable environment
title_sort mismatched diets defining the nutritional landscape of grasshopper communities in a variable environment
topic Acrididae
Australia
drylands
grasshoppers
insect herbivory
nutritional ecology
url https://doi.org/10.1002/ecs2.3409
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