About This Project

Whip scorpions (vinegaroons) such as the North American species Mastigoproctus giganteus - an unusual arachnid of the pet trade – spray acids at would-be attackers using a pair of pygidial glands. The recipe of this acid cocktail includes a variety of different compounds, but to date, the genetic, biochemical, and cellular bases for acid production remain a mystery. Here, we propose to investigate the genes and pathways in the pygidial glands that lead to this unique form of defense.

Ask the Scientists

What is the context of this research?

Whip scorpions are the only known arachnids to rely on the secretion and spraying of acids for defense. The identity of these acids continues to receive attention, but little is known about the glands that produce them or the genetic and biochemical basis of acid production. We recently began exploring these topics by first describing the structure of the pygidial glands. But even as we accumulate novel data about gland characteristics, we realize that a more complete picture of their function and evolution can only be had through an identification of the genes that are turned on and off (aka transcription) during secretion. So, in this project, we propose to generate the first transcriptome of a vinegaroon and identify which genes play a role in acid secretion in the pygidial glands.

What is the significance of this project?

All animals produce acids to aid in digestion, but few species make acids that function in defense. Using transcriptomics, we propose to generate gene expression profiles for the vinegaroon pygidial glands and compared them to their gut tissue to answer 3 questions: Do gland profiles match those of their gut tissue, which makes acids for digestion? Can transcriptomics provide insight into the development and evolutionary origins of the glands? Do expression profiles of the glands match those of other arthropods that also make acids for self defense (e.g., formicid ants)? Answers to these questions will provide novel and exciting insights into the history of whip scorpions and provide clues about how unique organ systems such as the pygidial glands evolved in this unusual arachnid lineage.

What are the goals of the project?

The goal of this research is to generate the first transcriptomic profile of whip scorpion pygidial glands as a basis for answering questions about their biochemistry and evolution. We know that different species produce different acid cocktails, but we know nothing about how they do it, why they do it, or how the glands evolved to generate different acids. Once we have sequenced M. giganteus, we can compare its transcriptome to other acid-producing arthropods (e.g., formicine ants) and begin sequencing other whip scorpions for comparison. This data will also help us and others to produce expression profiles of related animals that may have defensive glands but are difficult to work with due to their tiny size and cryptic nature (e.g., short-tailed whip scorpions and microwhip scorpions).