Unravelling the enigma of cave crickets

Even in the depths of a pitch-black cave, life continues to evolve. A prestigious Australian Biological Resources Study Postdoctoral Fellowship will help awardee Dr Perry Beasley-Hall and her team to unravel the evolutionary history of one of Australia’s most bizarre inhabitants.

Cave crickets (Family Rhaphidophoridae) are an enigmatic group of insects that eek out their lives almost entirely underground. In the lightless depths of a subterranean cave, eyesight is meaningless. Cave crickets instead rely on their spindly, elongated limbs and antennae to help them sense the world around them. Along with their eyesight, Rhaphidophoridae have also lost their wings, and their ability to chirp. It is a flightless, songless existence – and we’re only beginning to scratch at its surface.

We know little about how many cave cricket species there are, where they live, and how they’re related to one another. When did the earliest forms of cave crickets arrive in Australia? Who was their last common ancestor? How are they related and many times have sight, wings, and the ability to chirp de-volved throughout their evolutionary history?

[caption id="attachment_16377" align="alignleft" width="300"] Female cave crickets lay their eggs into mud in cave ceilings with ‘sword-like’ ovipositors, shown here. Photo: Steven Bourne[/caption]

These scientific questions are not only exciting in their own right - cave ecosystems are remote and often disconnected from one another, providing fascinating case-studies for evolution in action - but also crucial to conserving this cryptic group of insects.

We’re beginning to appreciate the important role that cave crickets play in their underground ecosystems – cycling nutrients by scavenging for bat poo or animal remains, and importing energy into an otherwise starved food web. We’re also starting to understand that these enigmatic creatures are in decline across Australia, and that their niche habitat requirements and inability to disperse long distances makes them vulnerable to change.

Conserving these evolutionary marvels will require us to take a fresh new look at their taxonomy. Recently, the Australian Biological Resources Study awarded a $300,000 Postdoctoral Fellowship Grant as part of the National Taxonomy Research Grant Program to Dr Beasley-Hall. Supported by the Environment Institute, Dr Beasley-Hall will document and describe the diversity of cave cricket species across Australia.

The project will run for three years. During this time Dr Beasley-Hall will use molecular techniques to reconstruct the evolutionary tree of Australian cave crickets, thereby unravelling the mystery of how they have evolved, and potentially giving formal scientific names to previously undiscovered species tucked away in remote caves.

Excitingly, the project will also help to raise awareness for these often overlooked creatures – engaging with avid caving enthusiasts, who often mistake Rhaphidophoridae for spiders, and creating online resources to help with cave cricket identification for researchers and citizen scientists alike.