Cryptic impacts of temperature variability on amphibian immune function
| Autor: | Kimberly A. Terrell, Matthew Evans, James B. Murphy, Bradley D. Nissen, Richard P. Quintero, Brian Gratwicke, John D. Kleopfer, Suzan Murray |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Amphibian
Physiology Population New York Urodela Aquatic Science Acclimatization Body Temperature Immune system Stress Physiological biology.animal Escherichia coli Animals education Molecular Biology Ecology Evolution Behavior and Systematics education.field_of_study Innate immune system biology Ecology Models Immunological Temperature biology.organism_classification Aeromonas hydrophila Insect Science Ectotherm Pseudomonas aeruginosa Linear Models Salamander Animal Science and Zoology Seasons |
| Zdroj: | The Journal of experimental biology. 216(Pt 22) |
| ISSN: | 1477-9145 |
| Popis: | Summary Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American salamander, we tested the hypothesis that naturally-occurring periods of temperature variation negatively impact amphibian health, either through direct effects on immune function or by increasing physiological stress. We exposed captive salamanders to repeated cycles of temperature fluctuations recorded in the population's natal stream and evaluated behavioral and physiological responses, including plasma complement activity (i.e., bacteria killing) against Pseudomonas aeruginosa, Escherichia coli and Aeromonas hydrophila. The best-fit model (ΔAICc = 0, wi = 0.9992) revealed 70% greater P. aeruginosa killing after exposure to variable temperatures and no evidence of thermal acclimation. The same model predicted 50% increased E. coli killing, but had weaker support (ΔAICc = 1.8, wi = 0.2882). In contrast, plasma defenses were ineffective against A. hydrophila, and other health indicators (leukocyte ratios, growth rates and behavioral patterns) were maintained at baseline values. Our data suggest that amphibians can tolerate, and even benefit from, natural patterns of rapid warming/cooling. Specifically, temperature variation can elicit increased activity of the innate immune system. This immune response may be adaptive in an unpredictable environment, and is undetectable by conventional health indicators (and hence considered cryptic). Our findings highlight the need to consider naturalistic patterns of temperature variation when predicting species' susceptibility to climate change. |
| Databáze: | OpenAIRE |
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