“Nice millipede,” Dr Olson cooed as the creature began to measure itself out across his palm. “Look at all those legs. It’s a classic creepy-crawler!”  To the uninformed eye this had looked like the perfect camping spot. My tent was pitched in a beautiful Costa Rican forest glade, sheltered by an ancient fig tree whose branches were so heavy that it had lowered vertical pillars to support their weight. It had seemed like a return to the benevolent arms of Mother Nature until the good doctor began to agitate the tree’s nocturnal inhabitants with a probing flashlight.



There were millipedes, too numerous to count, and swarms of giant cockroaches, four-inches long, that seemed to triple in size when they flew. There were scorpions that were capable of a painful sting that apparently has the side-effect of anaesthetising your tongue and lightning-quick whip-scorpions that were cunningly devoid of the tail that should have served as a warning to keep my distance. From out of the darkness I could hear Olson’s Bostonian accent proclaiming these “really neat…and they’re just soooo fast that I’ve yet to meet anyone who’s successfully gotten bit by one.”


There were also clouds of swarming bees (mercifully sting-less) that construct a single pipe for defence against the marauding army ants that frequently sweep across the campsite devouring everything in their path. Occasional swarms of Africanised bees (known inaccurately – “at least in most cases,” according to Dr Olson - as �?killer bees’) also buzz menacingly through the canopy from where Charlie, the leader of the resident howler-monkey troop, would blast out his blood-curdling wake-up call at 4am.


I had spent months travelling, relatively care-free, in jungles all over the world. But now Dr Olson was set to spend a few days clueing me in on what was really going on among the tinier denizens of this hive of murder, torture and rape. “For most mini-herbivores life is truly brutish and short,” he explained cheerfully.


He showed me �?tracker wasps’ that hunt down a particularly cute looking caterpillar so that they can impregnate its saliva-glands with their hellish offspring – with horrific accuracy they target the only part that has no immunity. He introduced me to a goofy-looking frog that hops obligingly onto your shoulder in the hope that you will blind yourself with its toxic excretions.


But Santa Rosa National Park is geared not towards entomological virgins of my ilk but towards the groups of seasoned – you might say �?hard-bitten’ – researchers that have come from all over the world to study everything from �?jaguar territorial requirements’ to �?parasitic infestations in the guts of assassin bugs.’


American ecologist Dr Daniel H. Janzen first brought recognition to Santa Rosa as the largest remaining tract of tropical dry forest and built it into one of the greatest research centres in Central America. He was the author of numerous scientific papers: as diverse as �?How to be a Fig’ and �?Allelopathy by Myrmecophytes: The Ant Azteca as an Allelopathic Agent of Cecropia.’ While a generation of young ecologists (Eric Olson included) were digesting these learned offerings, Janzen himself was in Santa Rosa digesting the seeds of numerous dry forest trees to analyse the effects of the mammalian bowel system on their germination. A tireless campaigner for Costa Rican parks, Janzen’s prodigious output has been a major weight in the preservation of the country’s forests.


Olson’s own team is principally studying the way in which caterpillars in this area predict the change of seasons to such an extent that they invariably arrive on the scene even before the trees have begun to push out their new shoots. The seasonal feeding-frenzy is so intense that a steady drizzle known as �?frass rain’ sprinkles down from the canopy as the caterpillars literally inflate themselves with vegetable matter. The best way to quantify the numbers of little grazers in the canopy is to harvest this �?frass’ and Dr Olson is supported in this task by volunteers from Earthwatch Institute who invariably have stories to tell about loved ones who are struggling to accept the fact that �?Mum has flown off to a remote part of Central America to spend a fortnight collecting caterpillar poop.’


“Humble bugs are the major converters of plant matter into animal matter in the tropical forest canopy,” Olson points out with an obvious feeling of awe that five years in the forest have not managed to diminish. Watch one of the doctor’s zebra swallowtail caterpillars feeding – and try as you might you just can’t do anything to stop them feeding – and it becomes easier to believe that these miniature herbivores are capable of eating more vegetation across a given area than the more intensely studied herds of the Serengeti. Research has already established that what were once labelled as �?pests’ are actually vital to the well being of the forest and that Latin American parks need to be interlinked in much the same way that Africa’s trans-frontier parks have been adapted to keep these migration routes open.


But there is much more to all this than �?caterpillar poop’ and his project had broadened to the stage where Dr Olson admits that, unlike his voracious subjects, he occasionally begins to wonder if he might have bitten off more than he can chew.


Apart from �?frassing’ and the collection and breeding of the butterflies, Olson is also constantly coming up with separate spin-off studies that have students searching the rainforest for undocumented species of jumping spiders, parasitoid wasps and whatever falls in their way as they, quite literally, beat the bushes in search of sundry �?creepy-crawlers.’ Among the doctor’s favourite discoveries is a unique spider that differs from all others in that it is not technically a hunter but makes a living by �?mugging’ ants: “It could be properly termed �?an obligate parasite of a mutualistic symbiosis,’” Olson grins, “…you want I should spell that?”