Abstract Detail

Systematics Section/ASPT

Long-Aragon, Nichole [1], Krosnick, Shawn [1].

The Structural Evolution of Butterfly Egg Mimicry within the Passionflowers (Passiflora L.).

The genus Passiflora, also known as Passionflowers, contains approximately 550 species and is one of the most widely cultivated genera of flowering plants. The flowers of Passiflora attract an immense range of pollinators. Bats, hummingbirds, and bees are part of this diverse following.In addition, Passiflora displays extra floral nectaries located on leaves and stem that attract ants, beetles,and wasps. Of all the insect visitors associated with the genus, Heliconius butterflies have an intricate and well-documented ecological relationship with Passiflora. Heliconius species lay eggs on the leaves of Passiflora and the caterpillars then emerge and feed on the plant, often completely defoliating it in just a few days. To combat this, Passiflora has evolved specialized egg mimic structures that deter gravid butterflies from laying their eggs on the leaves. While this is a famous example of co-evolution, relatively little is actually known about the egg mimics themselves. Therefore, the current study seeks to examine the nature of the egg mimics using anatomical, developmental, and morphological data. The following types of egg mimics were investigated: flowers (P. arbelaezii), leaf blade (P. allantophylla), leaf teeth (P. berteroana), stipules (P. cyanea), leaf apex (P. poslae), and petiole(P. triloba). Scanning electron microscopy was employed to examine both ultra structural and developmental details of the egg mimics. Paraffin embedded samples were sectioned to observe anatomical differences among the structures. The egg mimic structures were predominantly located on vegetative structures, though floral tissue produced egg mimics in P. arbelaezii. Passiflora arbelaezii had normal bud progression; however, the anthers lacked pollen and aborted prior to coronal development. There was substantial variety in the morphological and anatomical features of the vegetative egg mimics. For example, Passiflora poslae possessed nectaries beneath the egg mimic structure at the leaf apex. The distinct anatomical and morphological differences observed within of each type of egg mimic suggest at least six independent evolutionary origins of egg mimics in Passiflora. Selective pressures for reduction in predation may have been a driving force in the evolution of these structures.

Broader Impacts:

1 - Southern Arkansas University, Department of Biology, 100 East University Street, Magnolia, AR, 71753, USA

Keywords:
Passiflora
egg mimics
Heliconius.

Presentation Type: Oral Paper:Papers for Sections
Session: 5
Location: Rosedown/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 8:45 AM
Number: 5002
Abstract ID:147
Candidate for Awards:None