Evol Ecol Res 10: 787-796 (2008) Full PDF if your library subscribes.
On comparative analyses involving non-heritable traits: why half a loaf is sometimes worse than none
William E. Kunin
Earth & Biosphere Institute and Institute for Integrative and Comparative Biology, University of Leeds, Leeds, UK
Correspondence: W.E. Kunin, Earth & Biosphere Institute and Institute for Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK.
Question: Should phylogenetically informed (PI) analyses be used when not all variables in an analysis are heritable?
Methods: I simulated phylogenetic trees, with randomized traits (1) inherited with variation, (2) assigned directly to extant species, or (3) made partially dependent on a heritable variable, testing the frequency of ‘significant’ correlations between variables using conventional and two different PI techniques.
Results: ‘Significance’ was inflated in analyses of heritable variables, and this was corrected by both PI methods. However, where one variable was heritable and the other not, conventional analyses provided unbiased probability estimates. Modelled correlations between heritable and non-heritable traits were more readily detected by conventional analyses, but analyses involving ‘incorrect’ heritable traits sometimes showed spurious correlations.
Conclusions: The results suggest that PI analyses are inappropriate when only one of a pair of variables displays phylogenetic pattern. Where intrinsically non-heritable traits display phylogenetic pattern, conventional analyses are appropriate as an initial approach, but residuals should be tested for phylogenetic patterning.
Keywords: abundance, comparative method, correlated traits, distribution, heritability, independent contrasts, phylogenetic analyses.
DOWNLOAD A FREE, FULL PDF COPY
IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.
© 2008 William E. Kunin. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.
Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.
All copies of abstracts and articles must preserve their copyright notice without modification.