Richard B. Gump South Pacific Research Station

01 Aug, 01 PM - 20 Aug, 01 PM

Oedemeridae, also known as false blister beetles, is a family of elongate, soft-bodied beetles that produce a vesicant chemical called cantharidin. There are two species of Oedemerid beetles, Sessinia livida and Eobia bicolor from Moorea, French Polynesia with different elytral coloration and with potentially different sclerotization and melanization. Preliminary data collection and observations indicate that there may not be any difference in material properties of whole organisms between these two species but there may exist difference in cantharidin concentration. For this project, I aim to study the role of sclerotization and melanization of elytra in Oedemeridae. I plan to establish the phylogenetic relationship among Oedemerid beetles in the Society Islands of French Polynesia, examine biomechanical properties and structure of elytra, and measure composition and concentration of chemical defense mechanism of Oedemerid beetles to elucidate the role of elytra in Oedemeridae. The main research question is whether sclerotization/melanization of elytra contributes to toughness or physical defenses of the organisms and whether there is an association between chemical defenses and melanization of elytra in Oedemeridae, and whether any of these associations and traits have phylogenetic basis. There are seven species of Oedemeridae in French Polynesia and five of those (Eobia bicolor, Eobia decolor, Eobia kanack, Sessinia livida, and Thelyphassa lateritia) can be found in the Society Islands (Ramage 2017). I plan to initially focus on five species found in the Society Islands. I will measure mechanical properties of the whole organisms, mechanical properties of elytra, sclerotization of elytra, elytra coloration, and cantharidin concentration of each species. I aim to collect male and female individuals of each species of Oedemeridae found in the Society Islands of French Polynesia and examine material properties of whole organisms by conducting compression tests with a portable toughness tester, small-scale material properties of elytra using nano-indentation, elytral sclerotization and structures using SEM, and cantharidin concentration using gas chromatography/mass spectrometry analysis. I propose building phylogenetic tree of Oedemeridae using cytochrome oxidase subunit 1 (COI) gene sequences available on GenBank with additional sequencing for any missing species from the Society Islands. I hypothesize that sclerotization of elytra in Oedemeridae is not for physical protection, thus no difference in material properties under compression, while there is a strong association between melanization and cantharidin concentration and that the association is independent of phylogenetic relationship. Understanding the role of elytra in multiple contexts in a family of Coleoptera can be the starting point for studying the diverse range of elytral shapes, colors, and functions and help us understand how elytra may contribute to the extraordinary diversity of Coleoptera. Additionally, there have been multiple engineering attempts to develop materials inspired by beetle elytra. Understanding the biology and evolutionary process behind elytra can help us select and develop engineering designs and innovation inspired by elytra.

Visit #83858 @Richard B. Gump South Pacific Research Station

Approved

Under Project # 53047 | Research

The role of elytra sclerotization and melanization in Oedemeridae evolution

graduate_student - University of California, Berkeley

Reservation Members(s)

Hyee Ryun Lee Aug 1 - 20, 2023 (20 days)

Reserve Resources(s) | Create Invoice

Bed in shared room 1 Aug 1 - 20, 2023
Day User 1 Aug 1 - 20, 2023
General Use (Dirt) Lab 1 Aug 1 - 20, 2023