Question

animal behavior:

can quedtioned be answered fully and enough detail please

Ethologists have hypothesized that signal characteristics often evolve based on sensory preferences that already exist in potential receivers. You identify a lizard species in which males attract females with an orange dewlap. Males of a closely related species also have dewlaps, but they are the same gray color as the body. How would you test the hypothesis that orange dewlaps have evolved in the species of interest as a result of a pre-existing preference for the color orange in their females? Propose an experiment.

Answer 1

Dewlaps are flaps of skin beneath the chin that are extended and combined with head and body movements for visual signals and displays. They exhibit extensive morphological variation and are one of two cladistic features uniting anoles, yet little is known regarding their function and evolution. There are two separate hypotheses to test: (A) similar Anolishabitat specialists possess similar dewlap configurations (Ecomorph Convergence hypothesis), and (B) sympatric species differ in their dewlap morphologies to a greater extent than expected by chance (Species Recognition hypothesis).

The Species Recognition hypothesis predicts that sympatric species should evolve characteristics that aid in distinguishing conspecifics from heterospecifics. Application of this hypothesis to anoles predicts that sympatric species should have distinctly different dewlaps. This hypothesis has been examined or discussed in several studies that propose that dewlap colors have evolved to allow the rapid identification of heterospecifics.

Methods:

We collected information on dewlap color from detailed published literature, photographs taken in the field, and from experts familiar with these species. Descriptions in the literature and personal observations of dewlap colors did not follow any standard color scale; therefore, all dewlaps were classified according to conventional color categories. Spectrophotometric data would most objectively represent dewlap colors, but these data are currently available for few species. Our approach, then, is preliminary; taking advantage of the wealth of information on dewlap colors currently available, while recognizing that eventually such data will be refined by the availability of more precise and standardized spectrophotometric data. Categorizing color data will tend to underestimate diversity by lumping dewlaps that actually differ spectrally into the same categories. As a result, these data will tend to bias our study to incorrectly detect convergent evolution.

Phylogenetic Signal

We tested whether any phylogenetic signal exists for the category of dewlap color configuration within the context of a current anole phylogeny. For this test, we create a morphological distance matrices representing dissimilarities in color.