Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air

Amphibiotic dragonflies show a significant increase in hemolymph total CO 2 (TCO 2 ) as they transition from breathing water to breathing air. This study examined the hemolymph acid–base status of dragonflies from two families (Aeshnidae and Libellulidae) as they transition from water to air. CO 2 s...

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Published in:Journal of Experimental Biology
Main Authors: Lee, Daniel J., Matthews, Philip G. D.
Format: Text
Language:English
Published: The Company of Biologists Ltd 2019
Subjects:
Online Access:http://jeb.biologists.org/cgi/content/short/222/22/jeb210294
https://doi.org/10.1242/jeb.210294
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spelling fthighwire:oai:open-archive.highwire.org:jexbio:222/22/jeb210294 2023-05-15T15:53:00+02:00 Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air Lee, Daniel J. Matthews, Philip G. D. 2019-11-21 01:16:36.0 text/html http://jeb.biologists.org/cgi/content/short/222/22/jeb210294 https://doi.org/10.1242/jeb.210294 en eng The Company of Biologists Ltd http://jeb.biologists.org/cgi/content/short/222/22/jeb210294 http://dx.doi.org/10.1242/jeb.210294 Copyright (C) 2019, Company of Biologists RESEARCH ARTICLE TEXT 2019 fthighwire https://doi.org/10.1242/jeb.210294 2019-12-09T12:59:53Z Amphibiotic dragonflies show a significant increase in hemolymph total CO 2 (TCO 2 ) as they transition from breathing water to breathing air. This study examined the hemolymph acid–base status of dragonflies from two families (Aeshnidae and Libellulidae) as they transition from water to air. CO 2 solubility (α CO 2 ) and the apparent carbonic acid dissociation constant (p K app ) were determined in vitro , and pH/bicarbonate concentration ([HCO 3 −]) plots were produced by equilibrating hemolymph samples with P CO 2 between 0.5 and 5 kPa in custom-built rotating microtonometers. Hemolymph α CO 2 varied little between families and across development (mean 0.355±0.005 mmol l−1 kPa−1) while p K app was between 6.23 and 6.27, similar to values determined for grasshopper hemolymph. However, the non-HCO 3 − buffer capacity for dragonfly hemolymph was uniformly low relative to that of other insects (3.6–5.4 mmol l−1 pH−1). While aeshnid dragonflies maintained this level as bimodally breathing late-final instars and air-breathing adults, the buffer capacity of bimodally breathing late-final instar Libellula nymphs increased substantially to 9.9 mmol l−1 pH−1. Using the pH/[HCO 3 −] plots and in vivo measurements of TCO 2 and P CO 2 from early-final instar nymphs, it was calculated that the in vivo hemolymph pH was 7.8 for an aeshnid nymph and 7.9 for a libellulid nymph. The pH/[HCO 3 −] plots show that the changes in acid–base status experienced by dragonflies across their development are more moderate than those seen in vertebrate amphibians. Whether these differences are due to dragonflies being secondarily aquatic, or arise from intrinsic differences between insect and vertebrate gas exchange and acid–base regulatory mechanisms, remains an open question. Text Carbonic acid HighWire Press (Stanford University) Journal of Experimental Biology
institution Open Polar
collection HighWire Press (Stanford University)
op_collection_id fthighwire
language English
topic RESEARCH ARTICLE
spellingShingle RESEARCH ARTICLE
Lee, Daniel J.
Matthews, Philip G. D.
Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
topic_facet RESEARCH ARTICLE
description Amphibiotic dragonflies show a significant increase in hemolymph total CO 2 (TCO 2 ) as they transition from breathing water to breathing air. This study examined the hemolymph acid–base status of dragonflies from two families (Aeshnidae and Libellulidae) as they transition from water to air. CO 2 solubility (α CO 2 ) and the apparent carbonic acid dissociation constant (p K app ) were determined in vitro , and pH/bicarbonate concentration ([HCO 3 −]) plots were produced by equilibrating hemolymph samples with P CO 2 between 0.5 and 5 kPa in custom-built rotating microtonometers. Hemolymph α CO 2 varied little between families and across development (mean 0.355±0.005 mmol l−1 kPa−1) while p K app was between 6.23 and 6.27, similar to values determined for grasshopper hemolymph. However, the non-HCO 3 − buffer capacity for dragonfly hemolymph was uniformly low relative to that of other insects (3.6–5.4 mmol l−1 pH−1). While aeshnid dragonflies maintained this level as bimodally breathing late-final instars and air-breathing adults, the buffer capacity of bimodally breathing late-final instar Libellula nymphs increased substantially to 9.9 mmol l−1 pH−1. Using the pH/[HCO 3 −] plots and in vivo measurements of TCO 2 and P CO 2 from early-final instar nymphs, it was calculated that the in vivo hemolymph pH was 7.8 for an aeshnid nymph and 7.9 for a libellulid nymph. The pH/[HCO 3 −] plots show that the changes in acid–base status experienced by dragonflies across their development are more moderate than those seen in vertebrate amphibians. Whether these differences are due to dragonflies being secondarily aquatic, or arise from intrinsic differences between insect and vertebrate gas exchange and acid–base regulatory mechanisms, remains an open question.
format Text
author Lee, Daniel J.
Matthews, Philip G. D.
author_facet Lee, Daniel J.
Matthews, Philip G. D.
author_sort Lee, Daniel J.
title Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
title_short Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
title_full Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
title_fullStr Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
title_full_unstemmed Quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
title_sort quantifying the acid-base status of dragonflies across their transition from breathing water to breathing air
publisher The Company of Biologists Ltd
publishDate 2019
url http://jeb.biologists.org/cgi/content/short/222/22/jeb210294
https://doi.org/10.1242/jeb.210294
genre Carbonic acid
genre_facet Carbonic acid
op_relation http://jeb.biologists.org/cgi/content/short/222/22/jeb210294
http://dx.doi.org/10.1242/jeb.210294
op_rights Copyright (C) 2019, Company of Biologists
op_doi https://doi.org/10.1242/jeb.210294
container_title Journal of Experimental Biology
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