Mountain stoneflies may tolerate warming streams: Evidence from organismal physiology and gene expression

Global Change Biology
By: , and 

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Abstract

Rapid glacier recession is altering the physical conditions of headwater streams. Stream temperatures are predicted to rise and become increasingly variable, putting entire meltwater-associated biological communities at risk of extinction. Thus, there is a pressing need to understand how thermal stress affects mountain stream insects, particularly where glaciers are likely to vanish on contemporary timescales. In this study, we measured the critical thermal maximum (CTMAX) of stonefly nymphs representing multiple species and a range of thermal regimes in the high Rocky Mountains, USA. We then collected RNA-sequencing data to assess how organismal thermal stress translated to the cellular level. Our focal species included the meltwater stonefly, Lednia tumana, which was recently listed under the U.S. Endangered Species Act due to climate-induced habitat loss. For all study species, critical thermal maxima (CTMAX > 20°C) far exceeded the stream temperatures mountain stoneflies experience (<10°C). Moreover, while evidence for a cellular stress response was present, we also observed constitutive expression of genes encoding proteins known to underlie thermal stress (i.e., heat shock proteins) even at low temperatures that reflected natural conditions. We show that high-elevation aquatic insects may not be physiologically threatened by short-term exposure to warm temperatures and that longer-term physiological responses or biotic factors (e.g., competition) may better explain their extreme distributions.

Publication type Article
Publication Subtype Journal Article
Title Mountain stoneflies may tolerate warming streams: Evidence from organismal physiology and gene expression
Series title Global Change Biology
DOI 10.1111/gcb.15294
Volume 26
Issue 10
Year Published 2020
Language English
Publisher Wiley
Contributing office(s) Northern Rocky Mountain Science Center
Description 15 p.
First page 5524
Last page 5538
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