Leaf-Litter Connoisseurs: Part One

On his current expedition, Ronald Clouse ventures into the jungles of the Philippines to study harvestmen, or daddy-long-legs, of the order Opiliones. By collecting data for phylogenetic analysis, he hopes to learn more about the history of these creatures and the lands they inhabit.

Dr. Prashant Sharma is dwarfed by a limestone outcrop along the trail to Sibaliw Research Station. Photo by Ronald Clouse

We took the short cut up to Sibaliw (“si-BAL-yu”) Research Station, which meant it only took  about four hours to hike up 500 meters. The downside of this route was that the trail included several segments of near-vertical climbing on sharp limestone rocks, walking on poles balanced between ledges, and several sections where enormous trust was placed in the strength of little saplings and vines used for support. We had one porter for each of us, plus a guide, and they ran up the rocks in flip flops. I’ve been scampering around wet basalt rocks since spending several years in Micronesia as a child, but the jagged, partially eroded limestone terrain (“karst”) was a new challenge, especially when I was jet-lagged and unacclimated to the tropics. Oh, and then there were the layers of thorns, which made my winter-softened skin look like I had wrestled a crazed cat.

Thorns cover the leaves of this immature palm. Photo by Ronald Clouse
Thorns cover the leaves of this immature palm. Photo by Ronald Clouse
Porters and a guide rest during the hike to Sibaliw. Photo by Ronald Clouse
Porters and a guide rest during the hike to Sibaliw. Photo by Ronald Clouse

Nonetheless, after sweating a couple of gallons and drinking about as much, we reached the station, which was a comfy building on stilts in the forest, with a bamboo floor, separate bedrooms, a kitchen and dining area, and an outside shower house and outhouse (complete with a porcelain toilet!). The only glitch was that news of beds at the station prompted us to leave behind our sleeping bags. However, the beds didn’t include bedding, and even in the tropics it can get very cold at night at high elevations. So my first night was a long, sleepless one as I tried to curl my 6’9″ frame into a sphere. The next night Perry kindly loaned me his extra sarong, which was just enough to keep my legs warm.

Bamboo bed at Sibaliw Research Station. Photo by Ronald Clouse
Bamboo bed at Sibaliw Research Station. Photo by Ronald Clouse

All this was worth it, as the surrounding area had several large patches of forest undisturbed by humans, and under this we found the thick leaf litter so loved by Opiliones. The recent typhoon Yolanda (aka Haiyan) downed some large trees, but away from these openings we found good sites, especially at the bases of strangler figs, which begin their lives by enveloping another tree. Between their buttresses were piles of soft, rotting leaves, and there we found a variety of harvestmen. Our haul included four specimens of the rather picky and uncommon family Sandokanidae; we collected four specimens representing two species, but despite strenuous efforts on the last day, could find no more.

Examining sifted leaf litter for harvestmen at Sibaliw. Photo by Ronald Clouse
Examining sifted leaf litter for harvestmen at Sibaliw. Photo by Ronald Clouse

Listen to jungle sounds recorded at Sibaliw Research Station:

So I should tie up some loose ends here. Harvestmen are in the arachnid order Opiliones, and they are further subdivided into four suborders. Most of the specimens we are collecting in the Philippines belong to the suborder Laniatores. We are also collecting specimens in the suborder Eupnoi (“YUP-noi”), and those are the ones with little round bodies and very long legs most people see around their houses. They are active at night and like to stand on leaves. The very rare ones, known from only one adult specimen and three juveniles from across all of the Philippines, are in the suborder Cyphophthalmi (“SIYF-op-THAL-mee”… Don’t blame me!), and they are very compact, short-legged animals which live in stable, humid leaf litter.

Those of us who have studied under Professor Gonzalo Giribet and worked on Cyphophthalmi (“cyphos” for short) have learned to think like them and become connoisseurs of leaf litter. Cyphos need leaf litter that doesn’t dry out in the sun, doesn’t flood in the rain, and decomposes into a soft layer of little bits among which they can live their lives. They do not move into new areas very easily and as a rule do not cross rivers or large bodies of water; thus, as difficult as they are to find, their presence or absence gives great evidence of past land connections and ecological disturbance.

Watch more videos from this expedition

Read all posts by Ronald Clouse

To be continued… Check back soon to read about the next leg of Ron’s expedition!

Ronald Clouse investigates the histories of invertebrates found in the leaf litter. He works mostly with arthropods in the Indo-Pacific, especially harvestmen (daddy-long-legs) and ants. He also works with harvestmen in Brazil and the southern U.S., and he is interested in the processes by which we reconstruct history using DNA and morphology.

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