Ants. Ever wondered what they taste like? Neither have I. So when that question was put to me, as I stood beside a mound of them in the rainforest next to Puerto Rico's cascading Mucaro River, I misunderstood. My first thought was that my guide, Raymond, was warning me in a roundabout way to move on, in case the insects developed a taste for me.
I duly complied, whereupon Raymond began jabbing at the mound with a sharp stick. Ants don't like it when you do that. They immediately swarmed up the stick, so Raymond sensibly dropped it. But then he dipped his finger into the flow and, as soon as it was black, sucked it clean.
He was clearly after shock-horror, so I nodded coolly, as if the creatures had been chocolate spread. Error. Raymond dipped his finger again and held it up to me. "Your turn," he said.
As a rule, I don't suck other men's fingers. But I once bought a book by Ray Mears, and I like shorts with lots of pockets, so this challenge struck home. I jabbed my thumb in, let a dozen or so climb on board, then licked them off.
For a second they fizzed in my mouth. "Chew," Raymond advised. I did, but some of the insects had already made it under my tongue and on to the roof of my mouth. "Faster!" he suggested. I chewed and chewed until the spiky wriggling stopped.
"What do you think?" he asked.
"Sort of peppery."
"Exactly! Peppery alfalfa! Or sprouts!"
In truth, as well as my survivalist pretensions, I had two reasons for accepting the ant challenge. First, I wanted to help Raymond out. The excursion wasn't going well for him. Aside from his co-guide Josue and me, our group comprised an American hen party. Nothing wrong with that, in principle, but these hens were a bit headless.
The trip involved climbing waterfalls and across muddy canyons. Bring a daypack, water, and closed-toed shoes that can get wet was writ large on the instructions. The hens turned up late, bagless, waterless and in flip-flops, and then asked to go shoe-shopping en route to the rainforest. Half complained the road was too wiggly. When we finally arrived and Raymond began enthusiastically pointing out tiny tree frogs and giant snails, the other half squealed in disgust.
All of which was quite funny, if you weren't a tour organiser trying to show off the glories of your country's natural environment. But then one of the hens candidly announced this was her first trip to "South America", perhaps confusing Puerto Rico with Costa Rica (in Central America), and another asked Raymond where she could find an "Americans-only" bar.
At that point the hilarity soured: the only topic the guidebook suggests you should be wary of bringing up is Puerto Rico's relationship with the US. The island is a self-governing, unincorporated territory, or Commonwealth of the US, meaning it "belongs" to America, but is "not part of it". While the island's American-ness is visible along every inch of its well-maintained Subway-and-Burger-King-punctuated roads, independence is constantly and passionately debated.
My other impulse to ant-eat was more self-serving. Put simply, I preferred it to dancing salsa. I'd ducked the challenge of doing that the previous evening at Latin Roots, a fine restaurant and salsa club in Old San Juan. I went there with every intention of dancing, I really did. I'd even booked a lesson in advance. But as I sat at my table overlooking the dance-floor (eating a mouth-watering steak, served with spicy mashed mofongo – a local staple made from plantain), I lost my nerve.
Failure would have been so public. Cheerful, self-confident tourists were humiliating themselves right in front of me, next to some talented locals. More beer, normally so helpful, just made my problem more obvious. To dance salsa you need wiggly hips. To dance it spectacularly, like Wendy, my-teacher-who-would-have-been, you need at least four of them, all double-jointed. My own hips were spot-welded at birth. If (and it's a big if) I dance, it's an air-punchy affair, strictly vertical. Sorry, Wendy, I just preferred to watch you salsa with the other hipped people. I disappointed you, but I also let myself down.
I staggered out of Latin Roots determined to do something I could do, like stagger about, jotting things down in a notebook. In Old San Juan there was plenty to jot about. The stone-walled El Morro fort squats at the top end of the old city, overlooking the Atlantic, daring all-comers to have a pop at the original port-of-riches. During its five centuries many have had a go, including, in 1595, the "pirate" (the museum refers to him as such) Sir Francis Drake. Like just about everyone else, he failed.
I walked the city wall down to the port. Cruise ships deposit 1.5 million tourists here during the high season, which runs from November to May. That's nearly 10,000 visitors a day, attracted to the old city's picturesque, narrow streets, with its immaculately restored 18th-century houses, painted in delicate pastel shades. Think layered ice-cream cake: nice, but a bit too sugary. SUVs rumbling over the cobbles pumped out "reggaeton" (Hispanic reggae-hip-hop: more popular than salsa amongst young Puerto Ricans) through open windows into the hot evening air, adding a pleasing, discordant note.
I took a taxi to my hotel at the other end of the city, in Isla Verde, which isn't an island, and isn't green. It has an interesting sweep of city beach, though, backed by condos, malls and towering hotels. The bar on the top of mine (The Water Club) had a wonderful 360-degree view of the city, sea and nearby airport, from which I later caught a plane to Vieques Island, 20 minutes away.
Until recently, most of Vieques was off-limits to visitors. The US navy occupied it in 1941, and withdrew only in 2003, leaving a paradox in their wake: on the one hand this beautiful Caribbean island is largely undeveloped; on the other, it endured 50 years of target practice, and in parts the unexploded ordinance still needs clearing up. Arsenic, cyanide, napalm: it all rained down on the eastern tip of the island, which is still firmly out of bounds.
The rest of it isn't, though, and it's stunning: a dollop of lush greenery fringed with salt-white beaches. The W Hotels group, quick to spot an opportunity, opened a frankly incredible boutique resort on the north coast earlier this year. Once you've checked in, leaving requires surgical intervention, but there's a lot to see on Vieques, and one sight in particular – a bioluminescent bay – you'd be criminally negligent to miss.
I avoided prosecution by taking one of Abe's Bio Bay Tours. It didn't start auspiciously. Having hauled myself from the infinity pool, I found myself lurching through a mangrove swamp at dusk, in a battered van thick with mosquitoes. They shouldn't have come as a surprise: the "bio bay" is nicknamed Puerto Mosquito. But by the time I'd endured the safety briefing (dressed only in shorts and insects), the join-the-dots picture on my back resembled a Jackson Pollock, and I was worrying I'd precipitated an ant-related act of karmic retribution.
That being the case, the fact that there was nothing particularly "luminescent" about the water we kayaked through, each trailing our own bespoke mosquito cloud, came as a disappointment. But Abe had run this tour before. He gathered us around a buoy and explained – at length – how the near-constant water temperature (28C), dense mangroves, high saline content, and shallowness of the bay (15ft at its deepest) combine to produce a perfect environment for the super-abundant microscopic dinoflagellates. Their defence mechanism, when disturbed, is to release a chemical which reacts with the oxygen in the water to produce light, making this the brightest of a handful of such bays in the world. Which – itch-scratch, itch-scratch – was all very interesting, right up until the point when, dusk now dark, Abe told us to dip our hands in the blackness we were floating upon.
Boom. "Interesting" begat "Holy Cow!" as the bay exploded in clouds of greeny-blue billowing light. Abe told us to scoop up handfuls of water: the droplets running down our arms were luminous diamonds. I dived overboard. Light burst around me. I swam away, spotlit in the darkness: I was in Avatar; my fingers were lightsabres; my feet kicked up fountains of pearly light. It was wonderful, by which I mean a proper wonder of the world, absolutely worth every mosquito bite.
Back on the mainland, I drove two hours south to Ponce (pronounced pon-say). Like many second cities, fierce rivalry exists between it and the capital, San Juan. I'd not been in town 10 minutes before my charming guide, Nadine de Jesús Serrano, told me of a former mayor who came up with the amusing put-down: "Ponce is Ponce, the rest is parking". Unfortunately, the heir to his office has deemed that line derogatory, preferring: "Ponce is Ponce, the rest is friends and blessings". Oh well.
The fact is that Ponce is a gorgeous place, with every right to challenge San Juan. Its port is deeper and better suited to the biggest cruise liners. It made the city rich exporting sugar and rum in the 1800s. Much of the centre has been immaculately restored in recent years. It's full of Spanish colonial, neo-classical and art-deco buildings, painted creamy colours. The city feels cultured and laid-back. I went for a walk along the boardwalk down by the seafront, past eateries competing with smells and soundtracks, to watch families feeding enormous silvery fish beneath the pontoon.
I also climbed the hill to Museo Castillo Serrallés, the former home of a rich merchant family (who still have interests in the enormous Hilton complex, as well as the celebrated Don Q rum and many other ventures in town). The Moorish-inspired house is made almost entirely of concrete produced in Ponce, shaped and painted to look like stone and timber. It's oddly effective. Some of the rooms are given over to exhibitions, but most impressive is the fabulous view of the city from the terraced gardens.
Near Guánica, further west along the Caribbean coast, I went snorkelling with Ricardo and Roberto from the Copamarina Beach Resort. Protected by a coral barrier reef, the waters here are generally calm with excellent visibility, particularly early in the morning.
We chuntered out to the reef before breakfast, and I stepped blearily from the boat into a kaleidoscope of angelfish, red snappers, butterfly fish, sergeant majors, finger coral, starfish, brain coral, puffer-fish and flounders. There was even a moray eel and a barracuda. The local manatees weren't heffalumping about just then, but it didn't matter: I spent a couple of magical hours drifting among metaphors. Fan coral: slices of V C marbled ham. Tropical fish: Orla Kiely handbags.
Having followed Route 2 to Rincó*in the far north-west, where the Caribbean meets the Atlantic, I checked in for a night at the Horned Dorset Primavera Hotel. Pity it wasn't a week: I wore myself out jumping from the double-ended bath in the marble bathroom into the walk-in shower, and from there into the private plunge-pool on my veranda. Happily, the five-star dinner and four-poster bed helped me recuperate before the following day's surfing.
Rincó*is Puerto Rico's surfing capital. From here, right round the north coast, there are consistent breaks all year. During the winter months, surfers from all over the world descend to make the most of the swell, which is often huge. Garret Bartelt, of Rincó*Surf School, explained why. As well as weather patterns, trade winds and exposure to the Atlantic, the key factor is a huge trench that runs for 500 miles just north of the island. Waves gather power in deep water: the deepest point in the Atlantic (at 26,000ft) is in the Puerto Rico Trench.
Garret's mate, Colin, took me out for a day to the north shore at Jobos beach. First he talked me through "comfortability" in the waist-high waves. Then he admired my mosquito-bite-on-bright-white-torso collage ("National Geographic, dude!") while I complimented his tattoos and tan. And finally we paddled out into the glassy waves. I fell off a few. Colin didn't. We repeated that pattern for a while. But finally, with his guidance, I did manage to score a couple of righteous rides.
Having paddled my arms off, I flaked out on the plane home. But it was a fitful, dream-ridden sleep. Mostly the dreams were good: I was drinking cocktails with Johnny Depp in between takes for his latest film, The Rum Diary, which is set in Puerto Rico. I was flying in a magic car (Isla del Encanto is written on Puerto Rican number-plates) over phosphorescent waves. But at one point I dreamt that a column of ants was dancing its way through my open mouth. They taste of peppery sprouts. I know that now. And if my dream was right, I also know that real ant music has nothing to do with Adam. When ants dance, they salsa.
Travel essentials: Puerto Rico
* There are no direct flights between the UK and Puerto Rico. The writer flew from Heathrow to San Juan via New York with American Airlines (020-7365 0777; americanairlines.co.uk). British Airways (0844 493 0787; ba.com) offers a code-share with American Airlines from Heathrow via New York or Miami.
* Popcorn Tours tailors full itineraries in Puerto Rico (001 787 765 1776; popcorntours.com).
* National offers car rental from £36 per day (0871 384 11 40; nationalcar.co.uk).
* San Juan Water & Beach Club Hotel (001 787 728 3666; waterbeachclubhotel.com). Doubles start at $157 (£105), room only.
* The W Retreat and Spa, Vieques Island (001 787 741 4100; whotels.com/vieques). Doubles start at $409 (£327), room only.
* Copamarina Beach Resort & Spa, Guánica (001 787 821 0505; copamarina.com). Doubles start at $226 (£151), room only.
* Horned Dorset Primavera Hotel, Rincón (001 787 823 4030; horneddorset.com). Suites start at $446 (£298), room only.
* Acampa Nature Adventures runs half-day Mucaro Rainforest Zipline Adventure tours for $125 (£83) per person (001 787 706 0695; acampapr.com).
* Abe's Snorkelling and Bio-Bay Tours runs two-hour Bioluminescent Bay kayaking excursions in Vieques for $30 (£20) per person (001 787 741 2134; abessnorkeling.com).
* Rincon offers two-and-a-half-hour private surf lessons from £50 per person (001 787 823 0610; rinconsurfschool.com).
* Puerto Rico Tourism Company: 020-7367 0982; seepuertorico.com