Developing Dalotia coriaria, the Greenhouse Rove Beetle, as a Novel Model Organism

Citation

Miller, David Ryan (2023) Developing Dalotia coriaria, the Greenhouse Rove Beetle, as a Novel Model Organism. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/wwp6-xq35. https://resolver.caltech.edu/CaltechTHESIS:08172022-204326931

Abstract

This thesis deals with the development of Dalotia coriaria, the greenhouse rove beetle, as a novel model organism. A fundamental characteristic of metazoan life is inter-species interactions. Chapter 1 explores why there is a need for Dalotia as a new model organism to study these interspecies interactions in ways that are intractable with current established models. It also explores the life history characteristics of Dalotia that make it amenable to development as a novel model organism as well as the need for genetic access in order to successfully make Dalotia an established laboratory model organism.

Chapter 2 explores how I have solved the husbandry techniques required for genetic manipulations in Dalotia. These include the ability to collect large amounts of early embryos, mount embryos on slides, micro inject embryos, raise single housed larvae to adulthood, and set up one-on-one adult crosses.

Chapter 3 explores how I have developed the Piggybac transposon system to successfully knock in trans-genes into the Dalotia genome. It also shows how I have developed the UAS Gal4Δ binary expression system to work in Dalotia, allowing for controlled high expression of inserted trans-genes.

Chapter 4 explores how I have developed the CRISPR Cas9 system to successfully perform targeted germline point mutations in the Dalotia genome. It also shows how I have developed fast and accurate genotyping techniques for producing and maintaining homozygous stocks of mutant Dalotia for long periods of time. The appendices of this thesis include step-by-step protocols that allow for reproduction of all of the husbandry and genetic manipulation techniques covered in Chapters 2-4.

Lastly, Chapter 5 of this thesis explores olfactory receptor guided behaviors in Dalotia. I use RNA Smartseq techniques to produce a map of chemoreceptors across the Dalotia body. I also use the Dalotia CRISPR Cas9 protocol I developed to produce a homozygous line of olfactory receptor-deficient Dalotia by knocking out the olfactory receptor co-receptor. I show that the line of olfactory receptor-deficient Dalotia are incapable of olfaction, and then explore how it affects their defensive behavior when interacting with ants. These interactions are studied in a free moving arena and in a tethered beetle on the ball setup using machine learning to analyze pose.

Thesis Files