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Spotlight on our Postgraduates – Amanda Niehaus

The research that I did last year in the US and Brasil was lots of fun, and I learned a lot about working with other scientific styles in the process. In those 6 weeks, I was involved in the design and running of several different projects and worked on developing dynamic programming techniques and optimality theory to study thermal acclimation. Though it was an intense trip, I enjoyed a lot of Mexican and Brasilian food and American microbrews, and got to see how far my Spanish got me in a Portuguese-speaking country.

In the short-term, I’ll be finishing my PhD this August and having a baby in September. Next year (when I’m hopefully sleeping again), I plan to continue along an academic career track by expanding my collaborations with overseas researchers and working towards obtaining a postdoctoral fellowship to continue research. Following on from my PhD, I’d like to examine how environmental variability affects the ecology and evolution of ectotherms, ideally in a model system with important conservation or health value.


Enticing crickets to run in a CT room in Indiana at temperatures between 8-44C.

Research Summary

Though environmental conditions change around us all the time, relatively few laboratory studies have considered the consequences of diel temperature variation on organisms. Instead, most compare phenotypes among un-natural stable conditions, which limits how much we can say about organisms in the real world. In my PhD thesis, I use both theoretical and empirical approaches to understand how rapid temperature changes affect patterns of development and acclimation in ectotherms. In my research, I’ve raised striped marsh frogs (Limnodynastes peronii) and fall field crickets (Gryllus pennsylvanicus) in a range of conditions to determine whether:

  • the morphology, physiology and locomotor performance of organisms differs between stable and fluctuating temperatures as predicted by current acclimation theories
  • variability has carry-over effects between life-history stages
  • we can use data collected at stable environments to predict outcomes in fluctuating ones
  • organisms respond differently to unpredictable versus predictable variability

In answering these questions, I’ve measured a number of important life-history and physiological factors such as developmental rates, growth rates, swimming or jumping performance, metabolic rates, heart rates, and feeding patterns. Basically, I’ve shown that it’s difficult to predict phenotypes of organisms in fluctuating environments and that existing optimality and life-history theories do not adequately explain responses to short-term variability. I hope that my work will have important implications for experimental biologists, as it shows how incredibly important it is to use realistic thermal regimes in laboratory studies.



You can actually see the tadpoles' hearts through their bellies, making measurement of heart rate fairly simple.


Once I got very lucky and found some eggs in a scenic location while on a cycling trip.


Ephemeral pools where temperatures often vary dramatically every day.


My typical lab setup.
  My PhD research would not have been possible without the support of my PhD supervisors Craig Franklin and Anne Goldizen, my partner Robbie Wilson, and collaborators in the US (Mike Angilletta) and Sydney (Frank Seebacher).


Publications


Niehaus, A.C., M.J. Angilletta, C.E. Franklin and R.S. Wilson. In review. Predicting anuran phenotypes in complex thermal environments. American Naturalist.

Angilletta, M.J Jr., T.C. Roth II, R.S. Wilson, A.C. Niehaus, and P.L. Ribeiro. In review. The fast and the fractalous: Speed and tortuoisity tradeoff in running ants. Functional Ecology.

Angilletta, M.J Jr., R.S. Wilson, A.C. Niehaus, M. Sears, C.A. Navas and P.L. Ribeiro. 2007. Urban physiology: City ants possess greater thermal tolerance. PLoS One 2(2): e258.

Niehaus, A.C. and R.C. Ydenberg. 2006. Ecological factors associated with the migratory phenology of high-latitude breeding Western Sandpipers. Polar Biology 30:11-17.

Niehaus, A.C., R.S. Wilson and C.E. Franklin. 2006. Short- and long-term consequences of thermal variation in the larval environment of anurans. Journal of Animal Ecology 75(3): 686-692.

Ydenberg, R.C., A.C. Niehaus, and D.B. Lank. 2005. Interannual differences in the relative timing of southward migration of male and female western sandpipers (Calidris mauri). Naturwissenshaften 92: 332-335.

Niehaus, A.C., D.R. Ruthrauff, and B.J. McCaffery. 2004. Predator attraction to Western Sandpiper nest exclosures. Waterbirds 27 (1): 79-82.

Niehaus, A.C., S.B. Heard, S.D. Hendrix, and S.L. Hillis. 2003. Measuring edge effects on nest predation in forest fragments: Do finch and quail eggs tell different stories? American Midland Naturalist 149: 335-343.

 
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