Size-temperature responses of organisms and metabolic response to climate change S.K. Morgan Ernest...

Size-temperature responses of organisms and metabolic response to climate changeS.K. Morgan Ernest1, Kristina Anderson-Teixeira2, Felisa A. Smith3, Ethan P. White1

1Department of Biology and the Ecology Center, Utah State University, 2Energy Bioscience Institute, University of Illinois Urbana-Champaign, 3Department of Biology, University of New Mexico

Metabolic rate is related to size and temperature

Temperature also impacts ectotherm body size

Temperature impacts metabolic rate and body size in opposing ways

Large size decreases could offset temperature effect on metabolic rate

Data

Small impact on metabolic rate of size response to temperature

Forster et al (2011):•Generally, as temperature increases, body size decreases•80% of ectotherms examined exhibit significant size-temperature relationship •On average, adult body size decreases 2.5% per degree CDrosophila melanogaster

Data from Forster et al (2011)

Hypothetical responses of metabolic rate to temperature change and body size shifts

• Lab results of body size response to temperature

• 109 species from nine taxonomic Classes

• 85 spp. from Forster et al (2011), 24 spp. from other sources

Metabolic Rate

But does it?

•Estimated metabolic rate (B) using Gillooly et al (2001):

R=r0Mbe-E/kT

M mass, b scaling exponent, E activation energy

•Class specific b &E unless noted:

Quantifying metabolic responseto size and temperature changes • Q10 measures magnitude of

physiological responses to 10 C change in temperature

• Q4: magnitude of response over 4 CQ4= (R2/R1)4/(T2-T1)

Compare Q4 when size constant vs. varying

Generating Q4s for size constant vs. varying scenarios

Mean Q4 for size constant

Mean Q4 forsize response

Calculate %difference

Class b EActinoperygii# 0.78 0.35Amphibia 0.85 0.58Branchiopoda 0.79 0.31Entognatha* 0.75 0.63Eurotatoria* 0.75 0.63Gastropoda* 0.75 0.63Insecta 0.75 0.62Malacostraca 0.75 0.51Maxillopoda 0.69 0.68

* Theoretical values, # all fish

Less increase in metabolic Rate w/ increasing T

More increase in metabolic rate w/ increasing T

• Generally, size-temperature response dampens response of metabolic rate to temperature increases

• Magnitude of response is small

• Response consistent across taxonomic classes

• Except stronger response in Amphibia (but sample size small)

Rana pipiens. Data from White et al (2006)

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ReferencesForster, J., A.G. Hirst, D. Atkinson. 2011. How do organisms change size with changing temperature? The importance of reproductive method and ontogenetic timing. Functional Ecology 25:1024-1031Gillooly, J.F., J.H. Brown, G.B. West, V.M. Savage, E.L. Charnov. 2001. Effects of size and temperature on metabolic rate. Science 293 2248-2251White, C.R., N.F. Phillips, R.S. Seymour. 2006. The scaling of temperature dependence of vertebrate metabolism. Biology Letters 2:125-127.

AcknowledgementsSKME thanks USU for the post-tenure freedom to explore new ideas and start learning to programPhoto of Rana pipiens is copyrighted to Joyce Gross and obtained via Amphibiaweb.org

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Mass (grams) Initial size30 grams

NoSizechange

Decreasing size

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