Got a package a couple of days ago from Kauai. Not coffee or a sea turtle t-shirt or any of the other usual Hawaiian items, but something far more exciting—a small glass vial containing seven jumping bristletails preserved in ethanol! So, of course, I spent most of the rest of the day peering through a dissecting scope, trying to identify the things.
My friends/colleagues John Gatesy and Cheryl Hayashi and I have been studying these flightless insects for a number of years and can spout off various reasons why they’re fascinating from a “serious” scientific standpoint. But I just want to use these new Kauai specimens as an excuse to post a bunch of photos and give some sense of the attraction of these creatures for a geeky naturalist and taxonomist.
Mesomachilis nearctica in the Egan Range, Nevada.
Bristletails are extremely anatomically conservative—every bristletail pretty much looks like a bristletail. In a weird way, that’s part of their appeal; the diversity within the group is all about subtlety, not extravagant differences. And am I crazy or does this insect look kind of edible, like a tiny land shrimp?
Cheryl on Mt Moriah in the Northern Snake Range, Nevada.
The pale, carbonate rocks on Mt. Moriah might be 500 million years old, making them older, but not vastly older, than the bristletail lineage, which probably split 400 million years ago or so from the evolutionary branch that would become all other insects. Bristletails we collected here turned out to be a new, yet very abundant and widespread species.
Me, collecting on the Dana Plateau in the Sierra Nevada, just outside of Yosemite National Park. Photo by Seung-Chul Kim.
As John said on a recent collecting trip to Big Sur, bristletails seem to be found in really nice places (although one of the biggest concentrations of them I’ve ever seen was on an outhouse).
An especially handsome bristletail face—Petridiobius arcticus from Bellingham, Washington. Photo by Merrill Peterson.
Like other bristletails, this one looks like it’s wearing goggles and a gas mask. The elongate reddish brown blobs under the compound eyes are another pair of eyes, called lateral ocelli. Their shape is a key taxonomic character; looking at bristletails under a microscope, the first things I check out are the ocelli.
Neomachilis halophila from near Cambria, California.
When this bristletail was feeding, its compound eyes completely disappeared under the segment just behind them. (Compare the two photos. The white things are the lateral ocelli.) When I saw this, I got very excited and wrote to a couple of entomologist friends…and found out, to my slight disappointment, that having part of the head disappear like this happens in many kinds of insects. So it’s not unique, but it’s still kind of cool.
Neomachilis perkinsi from Kauai. Photo by Merrill Peterson.
At some point we learned that there are a few native bristletail species on the Hawaiian Islands and that they probably came from North America (which is weird—most Hawaiian arthropods, especially ones that don’t fly or drift on the air, came from other Pacific islands or from Asia). That led to several trips to Hawaii to collect specimens and verify the biogeographic story, still a work in progress at this point. The paired structures that are curved down sort of like fish hooks are the maxillary palps, which are used by the male to tap or grasp the female during mating, and are extremely thick in male perkinsi. This is the kind of thing that gets a bristletail taxonomist going.
One of the new specimens from Kauai.
This is a male, but it doesn’t have the thick maxillary palps, and, therefore, isn’t perkinsi. It’s probably Neomachilis insularis, a species never before identified from Kauai. Apart from the fact that these specimens may be a key for our biogeographic work, it’s just satisfying to be able to identify a species from a place where it’s never been found before.
John, on the island of Molokai, looking like he might try to flap himself airborne. The wings are actually “beat-sheets” used to collect arthropods.
Neomachilis halophila on driftwood on the Oregon coast. Is this how they got to Hawaii?
My kids on that same Oregon beach, presumably not thinking about taxonomy, long-distance dispersal, or the deep history of life on Earth.
Our son Eiji thinks bristletails are cool. But our daughter Hana keeps it real—“bristletails are dumb,” she says. (I think the subtext there is “When dad’s looking at those things under the microscope, he won’t play with me.”)
The Monkey's Voyage 