Date of Award

2001

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Entomology

First Advisor

Dorothy Prowell

Second Advisor

Christopher Carlton

Abstract

Although satyrine butterflies (Lepidoptera: Nymphalidae: Satyrinae) are highly diverse and found worldwide in most terrestrial habitats, they have received little attention from systematists. This research focuses on one of the largest satyrine groups, the euptychiines, found from central United States to Argentina, with the greatest diversity in the Amazon. The subtribe Euptychiina has a troubled taxonomic history. Most genera were erected without diagnoses and placed within the subtribe without being examined. Before this project was initiated, little was known of their basic biology and morphology. Therefore, considerable attention was given to this area in my research. I describe the larvae of 25 species and discuss morphological characters in detail, with chaetotaxy illustrations. Terminology of many morphological structures were reviewed and new terms proposed. Phylogenetic analyses using larval morphology and DNA sequence data found the subtribe paraphyletic. Five genera were excluded from the subtribe, redefined as Taygetiina. Numerous genera were also determined to be paraphyletic. Branching patterns were strongly supported with the larval data set, which was based on 157 characters taken from all instars. DNA sequence data between COI and EF-1∝ were largely congruent, although saturation and long branch attractions led to unusual groupings in the COI parsimony analyses, mostly resolved in the maximum likelihood tree. Incongruence between the morphological and molecular analyses revolved around placement of one taxon at the base of the ingroup. Placement of Megisto cymela in the ingroup or outgroup did not significantly alter the branching patterns of either data set. Three life history traits were mapped onto the phylogeny. Host use was conserved within the ingroup and diverse among the basal nodes. The ancestral satyrine grass-feeder is not known. Within Taygetiina, the two shifts to bamboo specialization were accompanied by a reduction in instar number. Ancestral reconstructions of these two traits were significantly associated. The selection pressure of predation and parasitism is thought to be a significant, but overlooked, force in the evolution of host use. I propose that the shift to bamboo (enemy-free space) and reduction in instar number (reduced vulnerability) were driven in part by parasitoid and predator pressure.

ISBN

9780493563213

Pages

368

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