Ivonne Garzon, University of New Orleans (Dr. Carla Penz)
Hamadryas is a Neotropical butterfly genus that includes 20 species (Lamas, 2004). As a group, Hamadryas butterflies vary in several life history traits such as aposematism (Chai, 1988), larval gregarious behavior (DeVries, 1987; Jenkins, 1983; Muyshondt and Muyshondt, 1975) and adult conspecific communication (Otero, 1990; Yack et al. 2000). These attributes make Hamadryas a suitable group to study evolutionary patterns. A phylogenetic reconstruction of their species-level relationships is an important step towards broadening our knowledge about Hamadryas in particular, and of Neotropical Lepidoptera in general. My research focuses on a total evidence (molecular and morphological) phylogenetic hypothesis for Hamadryas. The resulting topology will be used to: (1) provide morphological synapomorphies of the genus, (2) offer a testable hypothesis on the evolution of natural history traits, and (3) compare reconstructions from morphology vs. DNA data.
Initially, I will reconstruct a species-level phylogeny for Hamadryas using morphological characters. A detailed comparative morphology study will be performed to compile characters for phylogenetic reconstruction. A preliminary character list with 42 morphological characters has been assembled for Hamadryas, and I am currently expanding this character set. When the analyses are completed, natural history traits such as adult sound production, sexual dimorphism and aposematic coloration, egg clustering, and larval gregariousness and aposematic coloration will be optimized on the phylogenetic tree. This will allow me to ask if these characters resulted from convergent evolution or common ancestry. Furthermore, it will provide a mean for testing proposed mechanisms of the evolution of some of these traits; e.g., whether larval gregariousness is correlated with aposematism (Tullberg, 1988; Otero, 1990).
Concomitantly with the comparative morphology work, I am obtaining DNA sequence data. Sequencing of COI (mitochondrial), Wingless and EF1α (nuclear) will be conducted, given that these three genes have been successfully used in other butterfly studies (e.g., Monteiro and Pierce, 2001; Wahlberg and Freitas, 2007; Simonsen et al. 2006; Silva-Brandao et al. 2008). I will also combine morphological and molecular data as sources of independent evidence to propose a total evidence phylogeny. A hypothesis based on total evidence is preferred over analysis based on partial evidence because it represents a stronger test to the monophyly of the group, in addition to the fact that the use of different evidences increases the explanatory power of the hypothesis (Kluge, 1989; Eernisse and Kluge, 1993). However, it is not uncommon that morphology and DNA produce different estimates of phylogeny. Therefore, reconstructions from morphology and DNA will be compared on the basis of whether both support the same clades inside Hamadryas, or which clades are supported by a given type of data.
To proceed with the molecular analysis fieldwork will be conducted in Colombia, Brazil, Ecuador and Costa Rica to collect specimens. Ten species have been successfully collected in Colombia during the summer of 2008.