Date of Award

12-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

School of Materials Science and Engineering

Committee Member

Dr. Konstantin G. Kornev, Committee Chair

Committee Member

Dr. Olga Kuksenok

Committee Member

Dr. Peter Adler

Abstract

The feeding device of butterflies and moths, Lepidoptera, is called the "proboscis" and it consists of two complex-shaped fibers, galeae, which get linked together when the insects emerge from the pupa. The proboscis has been extensively studied by biologists, but has never been investigated from the materials science point of view. The following questions remain to be answered: What are the materials properties of the proboscis? How does the proboscis assemble and repair and what role do capillary forces play? What are the adhesion forces holding the galeae together during this assembly process? We have investigated and are exhibiting a methodology for studying the self-assembly and self-repair mechanism of the split lepidopteran proboscis in active and sedated butterflies. The proposed method can be extended to a bio-inspired characterization method of capillary adhesion for use with other samples. To probe the repair capabilities, we have separated the proboscis far from the head with a metal post of diameter comparable to the butterfly galea and moved the post ever closer to the head in increments of 500 microns until the proboscis was fully split. Once split, we brought the post back towards the tip in steps and observed the convergence of the two galeae back into one united proboscis. To determine the materials properties of the proboscis, the process of galeae gathering was filmed with a high speed camera. The galea profile, extracted from each frame of the videos, was then fitted with a mathematical model based on the Euler-Bernoulli beam theory where each galea was treated as a beam undergoing small deflections. The theory was augmented by introducing the bending moments modeling the muscular action and by a capillary force due to the saliva meniscus. Experiments on sedated butterflies, when the muscular action was diminished but saliva was present, show the crucial role of the saliva meniscus in bringing galeae together. The model sheds light on the evolutionary development of the butterfly proboscis.

Extracted B values used in Thesis_Final(1).xlsx (155 kB)
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Labview Codes.zip (1084 kB)
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