Effects of experimental warming on two tropical Andean aquatic insects.

Temperatures have increased around the globe, affecting many ecosystems, including high-elevation Andean streams where important aquatic insect species coexist. Depending on the magnitude of change, warming could lead to the mortality of sensitive species, and those tolerant to rising water temperat...

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Main Authors: Silvana Gallegos-Sánchez, Eduardo Domínguez, Andrea C Encalada, Blanca Ríos-Touma
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2022-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0271256
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author Silvana Gallegos-Sánchez
Eduardo Domínguez
Andrea C Encalada
Blanca Ríos-Touma
author_facet Silvana Gallegos-Sánchez
Eduardo Domínguez
Andrea C Encalada
Blanca Ríos-Touma
author_sort Silvana Gallegos-Sánchez
collection DOAJ
description Temperatures have increased around the globe, affecting many ecosystems, including high-elevation Andean streams where important aquatic insect species coexist. Depending on the magnitude of change, warming could lead to the mortality of sensitive species, and those tolerant to rising water temperatures may exhibit differences in growth rates and development. Taxon-specific optimal temperature ranges for growth determine how high or low temperatures alter an organism's body size. In this study, we observed the effects of different climate change scenarios (following three scenarios of the 2021 IPCC predictions) in two aquatic insect species distributed in high-elevation streams in Ecuador: the mayfly Andesiops peruvianus (Ephemeroptera: Baetidae) and the caddisfly Anomalocosmoecus illiesi (Trichoptera: Limnephilidae). We assessed how increased water temperatures affect larval growth rates and mortality during a 10-day microcosm experiment. Our results showed that Andesiops peruvianus was more thermally sensitive than Anomalocosmoecus illiesi. Mortality was higher (more than 50% of the individuals) in mayflies than in caddisflies, which presented mortality below 12% at +2.5°C and +5°C. Mortality in mayflies was related to lower dissolved oxygen levels in increased temperature chambers. Higher temperatures affected body size and dry mass with a faster growth rate of Andesiops peruvianus larvae at experimentally higher temperatures, suggesting an important response of this hemimetabolous species to stream temperatures. For Anomalocosmoecus illiesi, we did not find significant changes in mortality, body size or growth rate in response to temperature changes during our experiment. In situ outcomes of species survival and growth in Andean streams are difficult to predict. Nevertheless, our results suggest that at only +2.5°C, a water temperature increase affected the two insect taxa differentially, leading to a drastic outcome for one species' larvae while selecting for a more tolerant species. Our study suggests that climate change might produce significant mortality and growth rate effects on ectotherm tropical aquatic insects, especially Andean mayflies, which showed higher sensitivity to increased water temperature scenarios.
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spelling doaj.art-4c66f16510ab46379234ea2352c41f892022-12-22T03:41:20ZengPublic Library of Science (PLoS)PLoS ONE1932-62032022-01-01177e027125610.1371/journal.pone.0271256Effects of experimental warming on two tropical Andean aquatic insects.Silvana Gallegos-SánchezEduardo DomínguezAndrea C EncaladaBlanca Ríos-ToumaTemperatures have increased around the globe, affecting many ecosystems, including high-elevation Andean streams where important aquatic insect species coexist. Depending on the magnitude of change, warming could lead to the mortality of sensitive species, and those tolerant to rising water temperatures may exhibit differences in growth rates and development. Taxon-specific optimal temperature ranges for growth determine how high or low temperatures alter an organism's body size. In this study, we observed the effects of different climate change scenarios (following three scenarios of the 2021 IPCC predictions) in two aquatic insect species distributed in high-elevation streams in Ecuador: the mayfly Andesiops peruvianus (Ephemeroptera: Baetidae) and the caddisfly Anomalocosmoecus illiesi (Trichoptera: Limnephilidae). We assessed how increased water temperatures affect larval growth rates and mortality during a 10-day microcosm experiment. Our results showed that Andesiops peruvianus was more thermally sensitive than Anomalocosmoecus illiesi. Mortality was higher (more than 50% of the individuals) in mayflies than in caddisflies, which presented mortality below 12% at +2.5°C and +5°C. Mortality in mayflies was related to lower dissolved oxygen levels in increased temperature chambers. Higher temperatures affected body size and dry mass with a faster growth rate of Andesiops peruvianus larvae at experimentally higher temperatures, suggesting an important response of this hemimetabolous species to stream temperatures. For Anomalocosmoecus illiesi, we did not find significant changes in mortality, body size or growth rate in response to temperature changes during our experiment. In situ outcomes of species survival and growth in Andean streams are difficult to predict. Nevertheless, our results suggest that at only +2.5°C, a water temperature increase affected the two insect taxa differentially, leading to a drastic outcome for one species' larvae while selecting for a more tolerant species. Our study suggests that climate change might produce significant mortality and growth rate effects on ectotherm tropical aquatic insects, especially Andean mayflies, which showed higher sensitivity to increased water temperature scenarios.https://doi.org/10.1371/journal.pone.0271256
spellingShingle Silvana Gallegos-Sánchez
Eduardo Domínguez
Andrea C Encalada
Blanca Ríos-Touma
Effects of experimental warming on two tropical Andean aquatic insects.
PLoS ONE
title Effects of experimental warming on two tropical Andean aquatic insects.
title_full Effects of experimental warming on two tropical Andean aquatic insects.
title_fullStr Effects of experimental warming on two tropical Andean aquatic insects.
title_full_unstemmed Effects of experimental warming on two tropical Andean aquatic insects.
title_short Effects of experimental warming on two tropical Andean aquatic insects.
title_sort effects of experimental warming on two tropical andean aquatic insects
url https://doi.org/10.1371/journal.pone.0271256
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