About This Project

The marvelous coloration patterns on butterflies are due to the presence of scales-modified hairs which are secreted by single cells. Amazingly, many other groups of insects also have evolved scales. Weevils, one of the largest families of animals on the planet (over 60,000 species), are another insect group to possess scales. In order to understand how similar structures have evolved independently in different organisms, this study will compare scale development in weevils and butterflies.

Ask the Scientists

What is the context of this research?

This study is intended to serve as the basis of a larger, long-term project examining scale development in different insect lineages and understanding how these independent evolutionary events occurred.

Research on insect scales has focused primarily on butterflies, in which much progress has been made to understand scale structure and morphology (1-3), wing color pattern formation (4-5), and development (6-7). Some work also has been accomplished examining weevil scale structure (8), although much progress is being made here (Davis and DeMarr, unpublished data). New frontiers in scale research, including this study, will involve comparative work on the morphology between different lineages of insects possessing scales and their developmental mechanisms.

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What is the significance of this project?

Weevils are a kind of beetle and feed on numerous types of plants, which is why they also are pests of many agricultural crops (e.g., corn, wheat, coffee, oranges, etc.). A common example includes acorn weevils.

Scale structure and formation is a fascinating topic not only due to their beauty and structural complexity, in which single cells are able to produce diverse patterns, but because of their ability to reflect and generate such diverse colors (9), sparking great interest in the fields of bioengineering and nanotechnology. With regards to evolutionary and developmental biology, it is of great interest to comprehend how genes are expressed to form such anatomical features, as well as how divergent lineages of organisms have independently evolved complex features such as scales and why.

What are the goals of the project?

This project represents the beginning of a long-term research program, having goals that include genome sequencing to look at regulatory regions governing the expression patterns of scale-related genes. In this study, in order to better understand which genes are being expressed in a scale cell to produce its specific structure, deep DNA sequencing will be done of various developmental stages in the weevil during which the scales are forming. To characterize the formation of the scales, transmission electron microscope (TEM) imaging will be done of these various stages. ImmunoGold labeling, a technique allowing one to stain and visualize specific proteins using the TEM, will also be done to understand how some proteins are being arranged spatially within the scale cell during development.