He said, ‘So all we can do is gather as many samples as we can, and hope to get lucky?’

Grant squared her shoulders stoically. ‘That’s right. When you don’t know what you’re looking for, there’s no substitute for overkill.’

They stayed on the island for six days. Prabir didn’t exactly grow inured to the drudgery, but there was some consolation in being so tired every night that he could fall asleep the moment he was horizontal. They found twenty-three species of animals and plants that appeared to be novel, though Grant pointed out that the odds were good that one or two had simply failed to make it into the taxonomic databases.

The second island was another half-day’s sailing away. Within an hour of coming ashore, they’d seen what appeared to be the same thorny shrubs, the same flies, the same vicious ants.

They worked their way deeper into the jungle, staying within sight of each other but collecting samples independently. Prabir had rigged up software that took images from his notepad’s camera and searched the major databases for a visual match to any previously described species. Grant scorned this approach; she had no encyclopaedic knowledge of the region’s original wildlife, but she seemed to have acquired the knack of recognising subtle clues in body plan and coloration. At the end of the day, judged against the sequencing results, their hit rates had turned out to be virtually identical.

Prabir stopped beside a white orchid, a single bell-shaped flower almost half a metre wide. Its thick green stem wound around a tree trunk and ended in a skein of white roots that clung to the bark, wreathed in fungus but otherwise naked to the air. There was an insect sitting in the maw of the flower, a beetle with iridescent green wings. He crouched down for a closer look; he was almost certain that this was a species Grant had found on the previous island that had turned out to be modified. If so, it was worth taking for comparison.

He sprayed the beetle with insecticide and waited a few seconds. There was no death dance, none of the usual convulsions. He gripped it by the sides and tried to dislodge it, but it seemed to be anchored to the petal.

The flower began to close, the petals sliding smoothly together. Prabir drew his hand back, but the flower came with it; the sticky secretion that had trapped the beetle had also glued his fingers to its carapace. He laughed. ‘Feed me! Feed me!’ He grabbed hold of the stem of the orchid and tried to extricate himself by yanking his hands apart, but he wasn’t strong enough to break the adhesion, or tear the plant. It was like being superglued to a heavy-duty rope wound around the tree trunk.

The flower now loosely enclosed his forearm, and the reflex action hadn’t stopped. He tried to stay calm: pitcher plants and sundews took days or weeks to digest a few flies; he wasn’t likely to get doused in anything that would strip his flesh to the bone. He fumbled for his pocket knife and attacked the petal. It was tough and fibrous as a palm leaf, but once he’d punctured it he managed to saw through it easily enough, hacking out a piece around the beetle. The orchid began to unfurl immediately, maybe because he’d taken away the source of the attachment signal. But why hadn’t it closed on the beetle itself?

Grant must have seen him struggling; she approached with a look of concern that turned into an enquiring smile as she realised that he was uninjured.

Using the knife blade, he managed to lever one finger free of the beetle. Grant took his hand and peered at what was still glued to his thumb. ‘That’s extraordinary.’

‘Do you mind?’ Prabir pulled his hand back. ‘If you want to wait five seconds, you can have a proper look.’ He forced the tip of the blade between skin and carapace, and finally dislodged the beetle, with orchid fragment attached.

Grant picked it up and examined it. ‘I was right. It’s a lure.’

‘You’re joking.’ Prabir took it from her and held it up to the light, examining the petal edge-on. What he’d taken for an insect was an elaborately coloured nodule growing out of the plant itself. He said, ‘So a beetle comes along and tries to mate with this?’

‘A beetle to mate with it, or maybe something else that thinks it’s going to eat the “beetle”. It’s quite common for orchids to have one entire petal that looks like a female wasp or bee, as a pollination lure. But with an adhesive like that, I have a feeling the end result wouldn’t be a light dusting with pollen.’

Prabir re-examined the damaged orchid. There was no pool of digestive juices waiting at the bottom of the flower, but perhaps it would have secreted something if it had been able to close fully.

He passed the lure back to Grant. ‘Don’t you think it looks like that modified species you found a few days ago?’

‘Dark-green shiny wing cases, about two centimetres long? Do you know how many beetles would fit that description?’

‘I think it looks identical.’ Prabir waited for her to contradict him, but she remained silent. ‘If it is, isn’t that stretching coincidence? For a process that wakens old genes in this orchid to synchronise so perfectly with the same process in the beetle—’

Grant said defensively, ‘They might have been here together for millions of years. It’s not inconceivable that two independently recovered traits could reveal an archaic act of mimicry.’

‘But I thought the beetle wouldn’t look exactly like any of its ancestors. I thought you said the mixed embryology produced distorted body plans.’

‘The lure could be distorted too.’

‘Sure. But in the same way? When its morphogenesis is completely different?’

Grant regarded him irritably. ‘I really don’t think they look that similar.’

They’d been photographing everything; they didn’t need to wait until they were back on the boat to make a comparison. Prabir summoned up the image and offered her his notepad.

After almost a minute Grant conceded, ‘You’re right. They’re very close.’ She looked up from the screen. ‘I can’t explain that.’

Prabir nodded soberly. ‘Don’t worry; you’ll figure it out. Your hypothesis is still the only one I’ve heard that makes the slightest sense.’

Grant said drily, ‘You mean compared to Paul Sutton’s highly esteemed theory of Divine Cosmic Ecotropy?’

‘I didn’t mean it that way. The last I heard from Madhusree, all her university colleagues were completely stumped, so you still have the advantage on them.’

Grant gave him a weary smile. ‘Thanks for the vote of confidence. But remember how long it took me to confess to the idea. Do you really expect that these people would have been any more forthcoming with your sister?’

The third island was the largest of the six Grant had chosen, almost three kilometres across. Two weeks before, that had sounded like nothing to Prabir’s urbanised ear; he’d often walked that far and back across Toronto in his lunch hour. But the area was eight times greater than the total of the two islands they’d toiled on for six days each, and when he saw the dense jungle stretching back from the beach into low wooded hills, he finally felt the scale of it. It was a far more visceral reaction than anything he’d experienced flying over an ocean or a continent. Probably because Grant would want to gather samples from every last square metre.

They found a gap in the reef almost straight ahead as they approached. It was early afternoon, but Prabir begged for a full day off before they went ashore. They ended up spending three hours snorkelling along the reef, taking pictures but collecting no samples: Grant’s licence didn’t extend to the marine life, and so far there’d been no sign that the mutations did either.

Prabir couldn’t help feeling tranquil in the sunlit water; it was impossible to remain uncharmed by the colours of the reef fish, or the weird anatomy of the invertebrates clinging to the coral. Everything here was beautiful and alien, dazzling and remote. A thousand delicate, translucent fish larvae could die in front of him without evoking the slightest twinge of compassion, the kind of thing a chick or a rat pup in the beak of a hawk would have produced. It was this distance that made the spectacle seem so much purer than anything on land: the same vicious struggle looked like nothing but a metaphorical ballet. If his roots were here, he had no sense of it; his body had built its own tamed sea and escaped to another world, as surely as if it had ascended into interstellar space, too long ago to remember.