Plunging into total darkness to hang out with crawling critters may sound like a nightmare to some, but for Megan Porter and Becky Chong, it's one of the big perks of their jobs.
Porter and Chong, both professors at the University of Hawaiʻi at Mānoa, received a nearly $1.3 million grant from the National Science Foundation in 2022 to study biodiversity in Hawaiʻi Island's lava tubes.
Since then, they've spent countless hours underground, surveying the unique species that spend their entire lives out of light's reach.
On a Saturday in October, Porter and Chong took two of their colleagues into a cave system on the southern part of Hawaiʻi Island.
They said goodbye to the midday sun, then carefully picked their way through loose lava rocks to descend into the cave.
Once they had left the last rays of light behind, the field crew turned off their headlamps and took in the dark, which Chong and Porter likened to a "peaceful void."
"If you sit still, you can hear your own heartbeat. It's so silent," Porter said.
This practice engenders a certain reverence for the curious insects that have carved out biological niches within these caves.
"It's such a complex landscape to have to navigate and survive in," Chong said.
The keystone species in Hawaiʻi Island's lava tubes is a colorless, eyeless planthopper that secretes cotton-like wax from its rear and uses it to construct protective cocoons.
There's a native springtail, which looks like a sesame seed with legs and has a tiny, forked appendage that it uses to launch itself away from danger.
And the top of the food chain is the formidable cave wolf spider, which can grow up to 3 inches in length.
Biologist Frank Howarth first began documenting the fauna in Hawaiʻi's lava tubes in the 1970s. Porter and Chong said they are building on his work by trying to understand how different biological communities within the caves have evolved.
So far, they've helped to formally describe three new cave species, with more in the works. But both researchers feel like they're just getting started.
"There's still so much to do. We're still finding new species all the time," Porter said.
As above, so below
Hawaiʻi Island has hundreds of miles of underground tunnels created by lava flows.
During an eruption, lava rushing like a river towards the ocean will begin to cool around the sides and the top of the flow. That crust of hardened rock remains once the molten lava near the center has emptied out.
"And you're left with this tube inside the rock," Porter said.
It is not a good idea to enter these caves without permission from their stewards, as they may contain iwi kūpuna or other sensitive cultural sites.
They can also be treacherous. Porter, Chong, and their colleagues decked themselves out in protective gear before heading below ground. More than once on the trip, the telltale thwack of someone's helmet hitting the ceiling of a low passageway rang out through the caves.
And interacting with the cave critters requires great care. The field crew used paintbrushes to delicately brush away detritus while searching for specimens and made sure to tread lightly as they explored.
"A lot of the things underground are very good at sensing vibrations, and so they will feel you coming and disappear before you get there," Porter said.
Many of the insects in these caves never venture above ground, but their lives are tied to the surface environment. The food web of Hawaiʻi's lava tubes relies on the roots of the ʻōhiʻa tree, which provide critical nutrients to species like planthoppers.
These roots hang down from tunnel ceilings like strands of hair, and Porter said that without them, there would be almost no biodiversity within lava tubes.
“There'd be very, very few bugs down here, because there'd be nothing to eat,” she said.
The health of the cave ecosystem is therefore dependent on the health of Hawaiʻi's native forests.
Porter and Chang hope to better understand how factors like Rapid ʻŌhiʻa Death, a fungal disease that has killed more than one million ‘ōhiʻa trees, might shape the future of Hawaiʻi's subterranean world.
"And I still feel like we're just scratching the surface," Porter said.
The NSF award supporting Porter and Chong's research will conclude in 2026. The pair is currently working with Bishop Museum to update the Hawaiian Cave Arthropod exhibit in the Richard T. Mamiya Science Adventure Center.
Hawaiʻi Public Radio exists to serve all of Hawai’i, and it’s the people of Hawai’i who keep us independent and strong. Help keep us strong to serve you in the future. Donate today.
