I'm working on a project to evaluate some drivers of a behavior that is occasionally observed in amphibians. We've collected nearly a hundred instances in which this behavior was observed and reported. The plan is to analyze these data (in a phylogenetic context) to test a couple potential ecological factors (size and mating system) that might be associated with the occurrence of this behavior.
Because we've only searched for reports of this behavior, we are lacking species in which it has never been observed as our "control"/"null"/absences. In other words, currently all of our responses in the dataset are "yes - behavior occurred". We can't include every amphibian species (7000+) in the analysis, partly because we wouldn't have the necessary natural history information available, so we must select a subset of species. The biggest challenge is that it is possible that this behavior is not reported in many species because that species' behavior is poorly studied - these would not be desirable control cases, because we couldn't confidently say that it doesn't occur. We've speculated about finding "matched" species (from the same family or genus as each positive case) that are the best studied within that taxonomic group, minimizing the potential that the behavior was not reported simply because the species is poorly studied. But I'm not sure this is the best solution, nor is it clear how we would define how well a species has been studied. Has anyone dealt before with the problem of finding appropriate "control" or "negative" cases for a situation similar to this? Or, do you know of any papers in which a similar analysis may have been done? Is there another listserv out there that would be better suited for this question? Thank you in advance! Brad -- Bradley Evan Carlson Intercollege Graduate Degree Program in Ecology The Pennsylvania State University University Park, PA 16802 Email: [email protected] http://www.personal.psu.edu/tll30/index_files/carlson.htm<http://homes.bio.psu.edu/people/faculty/langkilde/index_files/carlson.htm> https://sites.google.com/site/bradleyecarlson/home
