CONNECTING THE DOTS OF NONLINEAR REACTION NORMS UNRAVELS THE THREADS OF GENOTYPE–ENVIRONMENT INTERACTION IN DROSOPHILA
Article first published online: 11 JUN 2012
© 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.
Volume 66, Issue 11, pages 3404–3416, November 2012
How to Cite
Rocha, F. B. and Klaczko, L. B. (2012), CONNECTING THE DOTS OF NONLINEAR REACTION NORMS UNRAVELS THE THREADS OF GENOTYPE–ENVIRONMENT INTERACTION IN DROSOPHILA. Evolution, 66: 3404–3416. doi: 10.1111/j.1558-5646.2012.01702.x
- Issue published online: 25 OCT 2012
- Article first published online: 11 JUN 2012
- Accepted manuscript online: 20 MAY 2012 09:41PM EST
- Received August 1, 2011 Accepted April 15, 2012
- Aristal branches;
- development time;
- phenotypic plasticity;
- sternopleural bristles;
- thorax length
Two contrasting views can characterize the attitude of many studies toward reaction norms (RNs). An “optimistic” view attempts to use a linear model to describe RN variation; and a “pessimistic” view emphasizes RNs complexity without using any model to describe them. Here, we have analyzed the shape of 40 RNs of five traits of Drosophila mediopunctata in response to 11 temperatures. Our results, along with several other studies, show that RNs are typically curves best explained by nonlinear models. Estimating the set of 40 RNs on the basis of three rather than 11 temperatures produces a scenario, typical of the pessimistic view, where the linear model is either nonsignificant or a poor explanatory model. Moreover, we show that RN nonlinearity can significantly affect the conclusions of studies using the linear model. We propose a middle ground view on RNs which recognizes their general nonlinearity. Such view could, on the one hand, explain part of the important phenomenon of genotype–environment interaction emphasized by the pessimistic view. Moreover, it may explain features and patterns which are being ignored by the optimistic view. We suggest the parabolic model as first step to reveal patterns which were ignored before, or not fully appreciated.