Research topics

Evolution of parental care

Sexual selection

Reproductive ecology

Kin recognition and inclusive fitness

Mate choice

Aposematism and mimicry



Chytridiomycosis in Peru






Island biogeography and explosive morphological radiation

The causes of pronounced morphological divergence among populations or closely related species of some animals are still widely debated.  Sometimes this variation appears to be arbitrary with respect to the environment. The poison frog, Dendrobates pumilio exhibits spectacular color and pattern polymorphism among populations, in the Bocas del Toro archipelago of Panama, where the species co-occurs with two other poison frogs (Phyllobates lugubris and Minyobates sp.) having little color or pattern variation among populations (Fig. 1).

By investigating population divergence among mitochondrial DNA sequences from the cytochrome b gene region, we have shown that the extreme color and pattern variation among populations within Dendrobates pumilio is not matched by higher levels of genetic divergence relative to P. lugubris or Minyobates sp., indicating that gradual divergence in allopatry and founder effects are unlikely to have caused the geographical color and pattern variation in D. pumilio (Summers, et al., 1997).

Currently, we are developing primers to amplify more variable regions of mitochondrial DNA (particularly the d-loop region), in order to investigate the phylogeographic relationships of the different populations of D. pumilio in more detail.  In particular, we would like to use these molecular markers to trace the sequence of vicariance events that separated the different populations of D. pumilio  during the formation of the archipelago, to reconstruct the sequence of color and pattern evolution in these populations.  I have submitted a grant to the National Geographic Society for funding to pursue this line of research.