• Skip to main content
  • Skip to secondary menu
  • Skip to primary sidebar
  • Skip to footer
Geographical

Geographical

Official magazine of the Royal Geographical Society (with IBG)

  • Home
  • Briefing
  • Science & Environment
  • Climate
    • Climatewatch
  • Wildlife
  • Culture
  • Geopolitics
    • Geopolitical hotspots
  • Study Geography
    • University directory
    • Masters courses
    • Course guides
      • Climate change
      • Environmental science
      • Human geography
      • Physical geography
    • University pages
      • University of Aberdeen
      • Aberystwyth University
      • Cardiff University
      • University of Chester
      • Edge Hill University
      • The University of Edinburgh
      • Oxford Brookes University
      • Queen Mary University of London
    • Geography careers
      • Charity/non-profit
      • Education & research
      • Environment
      • Finance & consulting
      • Government and Local Government
    • Applications and advice
  • Quizzes
  • Magazine
    • Issue previews
    • Subscribe
    • Manage My Subscription
    • Special Editions
    • Podcasts
    • Geographical Archive
    • Book reviews
    • Crosswords
    • Advertise with us
  • Subscribe

The weird creatures inhabiting the lava tubes of Hawaii

22 July 2022
3 minutes

A planthopper nymph feeding on the sap of ohi’a lehua tree roots in a lava tube
A planthopper nymph feeds on sap from the ohi’a lehua tree roots. Planthopper nymphs produce wax filaments from a gland on their abdomen and make a wax cocoon that protects them from predators. Image: Alan Cressler 

Unearthing the endemic Hawaiian species that have adapted to life below ground inside lava tubes


Beneath the surface of Hawaii lies a subterranean world inhabited by pale, eyeless creatures. The volcanoes that created the island chain also built labyrinthine systems of lava tunnels that extend for kilometres underground. The upper reaches shelter bats and invasive species such as rats, but in the dark zones – the deepest regions of the caves – life has had to adapt. 

Recent exploration of caves on Big Island by a team of researchers from the University of Hawaii at Mānoa has already uncovered species that are new to science. In March, the team was awarded a US$1.29 million grant to continue studying life in the lava tubes. ‘It’s pretty fortunate to be on a research project where almost every time we go out into the field we actually do discover something new, whether it’s a new species or a range expansion,’ says assistant professor Rebecca Chong. 

The pale thread-legged bug, or 'assassin bug', found in the lava tubes of Hawaii
The thread-legged bug is a predatory insect endemic to the lava tubes of Hawaii. Image: Alan Cressler

Lava tubes are found where volcanoes produce low viscosity lava, particularly a basaltic type known by its Hawaiian name, pahoehoe. As it cools, it hardens and forms a crust, like ice over a flowing river. The molten core eventually drains away to leave a cavity that drips as it solidifies, leaving speleothems such as stalactites – or ‘lavacicles’ – helictites and soda straws. In Hawaii, the first colonisers of this space are the life-sustaining roots of the native ‘ōhi’a lehua tree, which break through the ceiling and hang like feathery curtains. Some time later, cave-adapted arthropods move in. 

Common features of such creatures include shrunken wings and elongated appendages – expanded non-visual senses suited for life in the dark. ‘Species range from sap-feeding insects, known as planthoppers, all the way to detritivores and omnivores, like crickets and millipedes, to a range of top predators,’ says Chong. Hawaiian varieties, including the blind wolf spider and the assassin bug, are found nowhere else. Their discovery is significant as the islands have already lost a lot of their endemic biodiversity. 

The four-year research project will document new species and their ranges to form a biodiversity baseline and help answer bigger biological questions about how these subterranean ecosystems form. ‘Our grant is primarily focused on the Big Island of Hawaii, because there is so much habitat heterogeneity, but we also want to use what we find to look at how that biodiversity scales across the islands. And then, hopefully, that information can also be used to compare and contrast other island lava tube systems,’ says Chong.   

A cave-adapted spider, and endangered and endemic species
The cave-adapted little-eyed big-eyed spider (it has tiny vestigial eyes, but is blind) is also endemic to Hawaii’s lava tubes. Image: Alan Cressler

The researchers will survey across five volcanoes on the island, ranging from those that just erupted to the very, very old. Big Island is the youngest island in the chain – it’s still forming – and lava tubes can be found in abundance. 

However, these ecosystems have a limited lifespan. Most lava tubes are less than ten metres from the surface and on the older islands, such as Kaua’i, many have weathered away. Life in the caves is intrinsically linked to the landscape above ground, making it susceptible to human activities, climate change and the increasing spread of invasive species. One, an aggressive fungal disease known as rapid ‘ōhi’a death, is already decimating the forests that provide a primary source of food for these underground worlds.

Filed Under: Science & Environment Tagged With: Volcanoes, Worldwatch

Protected by Copyscape

Primary Sidebar

Subscribe to Geographical Magazine from just £4.99

Geographical subscriptions

Sign up to our newsletter and get the best of Geographical direct to your inbox

Popular Now

Mount Everest Climbing Crisis: Overcrowding, Deaths and Danger at the Summit

Mount Everest Climbing Crisis: Overcrowding, Deaths and Danger at the Summit

Following in the footsteps of explorers: The Royal Geographical Society Collection

Following in the footsteps of explorers: The Royal Geographical Society Collection

Climate justice in action: 25 years of the Ashden Awards

Climate justice in action: 25 years of the Ashden Awards

Chobe National Park, Botswana : Tourists in a boat observe elephants along the riverside of Chobe River in Chobe National Park

Top 10 Countries Leading the Way in Sustainable Tourism

Exporting extinction: How the Rich World Is Driving Global Biodiversity Loss

Exporting extinction: How the Rich World Is Driving Global Biodiversity Loss

Footer

  • Facebook
  • Instagram
  • LinkedIn
  • Reddit
  • TikTok
  • Twitter
  • YouTube

Geographical print magazine cover

Published in the UK since 1935, Geographical is the official magazine of the Royal Geographical Society (with IBG).

Informative, authoritative and educational, this site’s content covers a wide range of subject areas, including geography, culture, wildlife and exploration, illustrated with superb photography.

Click Here for SUBSCRIPTION details

Want to access Geographical on your tablet or smartphone? Press the Apple, Android or PC/Mac image below to download the app for your device

Footer Apple Footer Android Footer Mac-PC

More from Geographical

  • Subscriptions
  • Get our Newsletter
  • About Us
  • Contact Us
  • Advertise with us
  • Privacy policy
  • Terms & Conditions

Copyright © 2025 · Site by Syon Media