Title

Phylogenetic analysis of larval morphology among subspecies of Speyeria callippe

Poster Number

9

Lead Author Major

Biology

Format

Poster Presentation

Faculty Mentor Name

Ryan Hill

Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

As insects, butterflies are well-studied taxonomically. Though the adult morphology has been studied intensively, relatively little attention has been given to larval morphology. Studying the immature stages can provide an important perspective for systematics, because selection pressures on adult color pattern, the trait commonly used to delineate species, can cause extensive similarity within and between species. For example, in the butterfly Speyeria callippe the adult wing morphology may be selected for crypsis or mimicry, making sympatric species resemble one another and obscuring relationships. Larval morphology represents an independent set of characters that can be explored for systematic utility. The purpose of this study was to analyze the larval morphology of twelve of the 19 subspecies of Speyeria callippe in order to assess the utility of larval characters for systematics. Specifically, this study investigated relationships within S. callippe, a widespread polytypic species, to test whether larval morphology supports subspecies taxonomy. Building on previous work in the lab that described larval morphology including head capsule color, body color, scoli color, and other traits, digital images and rearing descriptions were used to create a set of standardized homologous characters. This set of characters was then scored to create a character matrix for use in phylogenetic analysis. Results indicate that larval morphology is variable among subspecies, but preliminary analyses indicate that the observed variation, coupled with relatively few characters, leads to weakly supported trees. The resulting character matrix may be combined with other information regarding adult morphology, ecology, and DNA sequence data to help better distinguish the subspecies taxonomy of S. callippe.

Location

DeRosa University Center, Ballroom

Start Date

25-4-2015 2:00 PM

End Date

25-4-2015 4:00 PM

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Apr 25th, 2:00 PM Apr 25th, 4:00 PM

Phylogenetic analysis of larval morphology among subspecies of Speyeria callippe

DeRosa University Center, Ballroom

As insects, butterflies are well-studied taxonomically. Though the adult morphology has been studied intensively, relatively little attention has been given to larval morphology. Studying the immature stages can provide an important perspective for systematics, because selection pressures on adult color pattern, the trait commonly used to delineate species, can cause extensive similarity within and between species. For example, in the butterfly Speyeria callippe the adult wing morphology may be selected for crypsis or mimicry, making sympatric species resemble one another and obscuring relationships. Larval morphology represents an independent set of characters that can be explored for systematic utility. The purpose of this study was to analyze the larval morphology of twelve of the 19 subspecies of Speyeria callippe in order to assess the utility of larval characters for systematics. Specifically, this study investigated relationships within S. callippe, a widespread polytypic species, to test whether larval morphology supports subspecies taxonomy. Building on previous work in the lab that described larval morphology including head capsule color, body color, scoli color, and other traits, digital images and rearing descriptions were used to create a set of standardized homologous characters. This set of characters was then scored to create a character matrix for use in phylogenetic analysis. Results indicate that larval morphology is variable among subspecies, but preliminary analyses indicate that the observed variation, coupled with relatively few characters, leads to weakly supported trees. The resulting character matrix may be combined with other information regarding adult morphology, ecology, and DNA sequence data to help better distinguish the subspecies taxonomy of S. callippe.