Research topics

Evolution of parental care

Sexual selection

Reproductive ecology

Kin recognition and inclusive fitness

Mate choice

Aposematism and mimicry



Chytridiomycosis in Peru






Molecular systematics of the poison frogs

One of the major projects in my lab is to reconstruct the evolutionary history of these frogs.  This is a daunting task, both because of the large number of species involved, and because they are spread from Nicaragua south across the central american isthmus, over the Andes mountains and across the length and breadth of the entire Amazon Basin.

Traditional approaches to the systematics and evolutionary relationships of these frogs have not been successful (Myers, et al., 1995).  The main problem has been that traditional characters used to infer relationships, such as morphological characteristics, are not sufficiently variable.  My approach to this problem has been to employ molecular characters, specifically changes in mitochondrial DNA sequences, to reconstruct evolutionary relationships using various types of phylogenetic analysis, particularly parsimony and distance-based analyses.  This approach has been successful, and has already contributed to a clearer understanding of relationships among species of poison frogs in Panama (Summers, et al., 1997), and to the reconstruction of relationships among species and "species groups" in the genus Dendrobates (Summers, et al., 1999).

In the last few years my graduate student, Mark Clough, and I have completed a framwork for the evolutionary history of the poison frogs (Fig. 2; Clough & Summers, in press).  Using mitochondrial DNA sequence data, we have reconstructed the evolutionary history of 26 species, including representatives of each of the previously described toxic genera of the poison frog family (Minyobates, Epipedobates, Phobobates, Allobates, Phyllobates and Dendrobates).

This is an important first step, but much work remains to be done.  Major portions of the evolutionary tree of poison frog relationships remain to be elucidated.  Particularly poorly understood are the relationships among the myriad of species of both Dendrobates and Epipedobates that live in the vast rainforests spanning the transition between the Andes mountains and the Amazonian lowlands in eastern Peru.  This past summer I had the opportunity to work with Rainer Schulte, a biologist in Peru, who has been working on the poison frogs in that country for twenty years.  Mr. Schulte has been searching for a collaborator to investigate the molecular systematics of the poison frogs of Peru.  With permission from the peruvian government, Mr. Schulte and I collected tissue samples (toes from adults and tails from tadpoles) from many species of peruvian poison frogs.