The Usefulness of Behavior for Phylogeny Estimation: Levels of Homoplasy in Behavioral and Morphological Characters

Abstract

It is widely believed that behavior is more evolutionarily labile and/or more difficult to characterize than morphology, and thus that behavioral characters are not as useful as morphological characters for estimating phylogenetic relationships. To examine the relative utility of behavior and morphology for estimating phylogeny, we compared levels of homoplasy for morphological and behavioral characters that have been used in systematic studies. In an analysis of 22 data sets that contained both morphological and behavioral characters we found no significant difference between mean consistency indices (CIs, which measure homoplasy) within data sets for the two types of characters. In a second analysis we compared overall CIs for 8 data sets comprised entirely of behavioral characters with overall CIs for 32 morphological data sets and found no significant difference between the two types of data sets. For both analyses, 95% confidence limits on the difference between the two types of characters indicate that, even if given the benefit of the doubt, morphological characters could not have substantially higher mean CIs than behavioral characters. These results do not support the idea that behavioral characters are less useful than morphological characters for the estimation of phylogeny.

The Reconstruction of Ancestral Character States

“…Also open to investigation is the general claim that entire classes of characters, e.g., "most traits typically studied by evolutionary ecologists" (Frurnhoff and Reeve, 1994: 175-176), are especially prone to parallelism. This is at least partly contradicted by the surveys of de Queiroz andWimberger (1993) andWenzel (1992), which demonstrate that, T.R. Schultz, R. Cocroft, and G.A.…”

Labile evolution of display traits in bowerbirds indicates reduced effects of phylogenetic constraint

“…A bower is a stick structure built on or adjacent to a display court that is entered by one or both sexes during courtship and mating. It has been suggested that morphological and behavioural characters may be as useful as molecular characters in reconstructing evolutionary history (de ueiroz & Wimberger 1993), but this hypothesis has rarely been tested with characters under extreme sexual selection. Bowerbirds are an ideal group in which to test this hypothesis as they appear to be subject to strong sexual selection and exhibit great variation among species in the form and elaborateness of exaggerated, sex-limited display characters, including bowers, bright plumage and decorated display courts.…”

Recognizing and Testing Homology of Courtship Displays in Storks (Aves: Ciconiiformes: Ciconiidae)

“…Of the 46 characters in the behavioral data matrix, 13 have a consistency index less than one when mapped onto the DNA-DNA hybridization tree (Table 1). In terms of percentage of homoplastic characters, the amount of homoplasy in the behavioral characters is typical for phylogenetic data sets (Sanderson and Donoghue 1989;de Queiroz and Wimberger 1993). Stork display behaviors exhibit substantially different levels of variability across species; within species, any given display is essentially invariant, based on Kahl's extensive observations (KahI1966, 1971a(KahI1966, ,b, 1972a(KahI1966, -e, 1973.…”

“…In the field of behavior, the renewed historical perspective emphasizes both the application of phylogenetic information to study the evolution of behavior and the reciprocal use of behavioral characters to estimate phylogenetic relationships. Several recent studies (Arntzen and Sparreboom 1989;Carpenter 1989;Coddington 1990;McKitrick 1992;de Queiroz and Wimberger 1993;Sheldon and Winkler 1993;Wenzel 1993;Paterson et al 1995) contradict the notion that behavioral traits are too plastic to retain historical informationa notion that has prevailed since the 1970s (Atz 1970). In particular, avian display behaviors have been found to be reliable indicators of phylogenetic relationships and to map consistently onto phylogenies based on morphological and molecular data (Prum 1990;Foster et al 1996;Irwin 1996;Kennedy et al 1996).…”