When I was at university, involved in the cutting-edge discipline of sponge classification, I regarded ecology as “soft” science, suited to those who lacked the intellectual molars to chew more demanding meat. Ecologists, I liked to think, were the ones Mark Twain had in mind when he wrote, “There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”

Now I think differently. Ecology is about getting the big picture. And today, with the extinction rate in overdrive and ecosystems in crisis, how sorely humankind needs that perspective. Candy Feller’s CV calls her an insect ecologist, but this really means she’s interested in everything that has to do with an insect’s world of interactions, which is a wide world indeed. Tracking those interactions may entail analysing the sugar content of flower nectar or making aerial surveys of mangrove deforestation as much as it involves slicing open twigs to see what’s living inside.

Candy is part of an ecological subdiscipline called biocomplexity, the study of the mechanisms—physical, chemical, biological—that determine ecosystem structure and function. She came to mangrove ecology in an unusual way. She was a scientific illustrator, and was assigned to draw the underwater component of a mangrove ecosystem. Actually to draw under water, using waterproof materials and a scuba tank.

She found she liked mangroves. They reminded her of the rhododendron forests of her youth—the feeling of being enclosed and embraced by nature. These days Candy lives in Maryland, but at heart she’s a Carolina gal. I asked her what her favourite southern comfort food was. “Squirrel,” she said, without missing a beat. When she was little she and her brothers used to go out and shoot squirrels for breakfast. It was pretty much a no-brainer to find out she liked bluegrass music as much as I do. We swapped stories—I’d backed Emmylou Harris on a New Zealand TV show; she’d met Gid Tanner of the legendary Skillet Lickers. Then she opened up the iTunes playlist on her laptop and we spent an hour getting high and lonesome on four-part harmony.

When she retires she says she’s going to work on a plant called Jack-in-the-pulpit, which was found recently to be pollinated by thrips. She finds that an interesting interaction—thrips are normally thought of as pests, not beneficial pollinators. “I don’t want to publish, just to know,” she says. “I like the idea of pushing my walking frame into the garden and studying wildflowers.”

Watching Candy in the field, I’m pretty sure the walking frame is a long way in the future. By midday I’m wilting in the heat, with Noel Coward’s lyrics about mad dogs and Englishmen running through my head, but Candy, mud-spattered and sweating, presses ahead with the work. She doesn’t miss much, either. Today she found a fish I had been hoping to see: the mangrove killifish, or Rivulus. It was swimming in a shallow puddle in the Pelliciera forest, darting down fiddler crab burrows when it was disturbed.

Rivulus is the only known vertebrate capable of breeding without a mate. It can develop male and female sex organs and fertilise its own eggs. What’s more, it can breathe air through its skin, like a frog, and one specimen spent 66 consecutive days out of water, living in a hole in a tree. The fish’s ability to survive out of water comes in handy for Rivulus researchers, Candy said—they swap live specimens through the post.

When the field work was over for the day we explored a new river system. We passed groves of Pelliciera where the buttress roots and their reflections produced rows of diamonds at the waterline. Candy stood in the bow of the boat, surveying the forest, enthusing about the epiphytic orchids, wondering out loud why the Pelliciera on this coast seem to reach a certain height and then stop growing. The birders in the group had eyes only for trogons, toucans and other avian exotica, but I suspected that Candy’s mind was on the mangroves, pondering how they fit into the complex ecological pattern she is helping define.

I came across a statement from the late great US writer John Updike. His goal as a writer, he said, was “to give the mundane its beautiful due.” It seems to me that this is what Candy Feller is doing for mangroves, and I admire her for it.

We’re off again, as Candy Feller says, “like a herd of turtles.”

With us today are a couple of Smithsonian communications people, filming a documentary piece on Candy, and David Luther, a bird expert who works on the conservation of endangered species at the University of Maryland. A paper of David’s on vertebrates which rely on mangroves is about to be published in the journal Bioscience. This is good news for me, because I was hoping to find a list of mangrove-dependent creatures, and David has produced that very list—for vertebrates, at least. David says that almost half of these mangrove endemics—48 birds, 14 reptiles, 1 amphibian and 6 mammals—are endangered, many of them critically so.

One of his mangrove species is chattering in the branches as we wheelbarrow our gear to the boat: the mangrove yellow warbler, a canary-sized bird with canary-coloured plumage. The male has a rusty red head, as if it had been dipped in paprika.

We weave our way through the Bocas archipelago and cross the bay to the Peninsula Valiente. The sea is silky calm and dotted with the canoes of the Ngöbe Buglé people native to this area. They are fishing, diving or just commuting; rivers and sea are the only roads in this area.

We stop at a village which looks like a film set: rough timber buildings on stilts at the water´s edge, blue smoke drifting through almond trees, jungle rising thickly behind. Half an hour further on and we come to Candy’s site: a forest which includes the mangrove species known as Pelliciera rhizophorae.

Candy has a special affection for Pelliciera, which has one of the most restricted distributions of any mangrove. It occurs on the Pacific coast of Latin America from Costa Rica to northern Ecuador, and in just a few spots on the Caribbean coast. The trees have elegant fluted buttresses, straightish trunks and long spindle-shaped leaves. But their flowers are what set them apart. Almost all mangroves have small, unspectacular flowers—except Pelliciera, which breaks ranks by producing flamboyant, star-shaped, nectar-filled blooms. The nectar attracts hummingbirds (believed to be the main pollinator) as well as many insects. We even find tree crabs taking a dram. Pelliciera blooms year-round, but when flowering is at its peak the forest is alive with the whirring wingbeats and squeaking calls of hummingbirds. “Imagine being strafed by hummingbirds,” Candy says.

On a previous trip Candy discovered something unusual: when she shone a UV light on the flowers the nectar fluoresced. Today she wants to take nectar samples and have them analysed in a lab that specialises in fluorescence. This turns out to be too easy. The flowers produce so much nectar that she can fill a glass capillary tube in seconds—if, that is, she beats me to it. I’ve been in a sugar desert lately, and am making up for it by licking Pelliciera nectar (it has a delicate caramel flavour).

I walk through the forest, scouting for flowers and for the peacock flash of blue morpho butterflies, whose seemingly random fluttering always seems to be out of camera range. For a while, the best I can achieve photographically is a morpho at rest on a mangrove leaf, when the heavenly blue is hidden, and all you see are an eye-patterned grey and black. Then I find a butterfly trapped in a golden orb spider’s web, with the spider feeding on its dead body. It seems unsporting to photograph the iconic creature’s demise, but it could be my only chance to record the wing colour, so I shoot a few frames. “Frames”—the old film terminology lingers. “Files” doesn’t have the same magic.

We eat lunch of boiled eggs, tomatoes and bread, and are treated to the sight of a basilisk, or “Jesus Christ lizard” running across the river and up a mangrove tree. “Basilisk,” I learn, comes from the Greek for “little king,” a name bestowed by none other than Carl Linnaeus, father of taxonomy.

Candy, Emily and Anne follow a similar collecting pattern as yesterday, gathering seedlings, twigs and flowers, collecting crabs and, on this occasion, measuring the salinity of the peaty mud in which the trees are growing. I help with the fiddler crabs, whose large claw has an off-puttingly wide set of pincers at the tip. I find that their posture is worse than their pinch, and manage to collect several without being nipped.

We arrive back at the lab at sunset, and though it’s been a long, hot day Candy can’t resist putting in a couple of hours in the lab, slicing into the twigs and seedlings with a knife to see what’s living inside.

In front of the main building two bat researchers have set up a mist net and are catching bats at a rate of one every couple of minutes. Just as in nature, institutions like the Smithsonian have their diurnal and nocturnal residents. We mangrovistas are winding down, thinking of gin and tonics and what’s for dinner, while the bat brigade is gearing up for a night of excitement. The main researcher thinks he may have captured a new species.

I take a torch down to the boat ramp and spotlight the mangroves, watching tree crabs chomping leaves and flowers. Howler monkeys are making a racket in the jungle beyond the lab, while poison dart frogs keep up a constant chirruping. It’s a great life, and tomorrow I get to do it all over again!