Grant joined him on the deck, beaming madly. She must have caught a trace of bemusement on his face; she said, ‘I know, but I can’t help it. A sky like this makes my poor heart sing. Sunlight deprivation as a child, I suppose; when I finally get a good dose of it, my brain just wants to condition me to come back for more.’
Prabir said, ‘Don’t apologise for being happy.’ He hesitated, then added obliquely, ‘Everyone else I met in Ambon who’d arrived from temperate regions seemed to have suffered rather less beneficial effects.’
Grant feigned puzzlement. ‘I can’t think who you could mean. Mind you, some people really do go a bit psychotic when they hit the tropics for the first time. That’s the down side. But you must have encountered that before, surely?’
‘The British Raj was a bit before my time.’
Grant smiled, then closed her eyes and raised her face to the sky. Prabir glanced back towards Ambon, but the grey smudge on the horizon had vanished. He’d have happily stood in silence like this for hours, but that was too much to hope for; what he really needed was a topic of conversation that wouldn’t keep leading them back to his supposedly boundless familiarity with everything in sight. Grant was hardly going to throw him overboard if she caught him out on some minor inconsistency, but if the whole mess of half-truths unravelled and he was forced to confess just how limited and rusty his grasp of the region’s language, custom and geography really was, he wouldn’t put it past her to abandon him on the nearest inhabited island.
He said, ‘What do you think’s going on here? With the animals?’
‘I have absolutely no idea.’
Prabir laughed. ‘That’s refreshing.’
‘I do have a few vague hypotheses,’ Grant admitted, opening her eyes. ‘But nothing I’d reveal except under extreme duress.’
‘Oh, come on! You’re not talking to a fellow biologist here. I’m much too ill informed to recognise heresy, and my opinion has no bearing on your reputation anyway. What have you got to lose?’
Grant smiled and leant on the railing. ‘You might blab to your sister, and then where would I be?’
Prabir was affronted. ‘Madhusree can keep a secret.’
‘Ha! Her, not you! That shows how far I can trust you.’
Prabir said, ‘What if some kind of toxin, some kind of mutagenic poison had been dumped on one of the uninhabited islands here, decades ago? A few dozen drums of industrial waste, chemically related to the kind of stuff they use to induce mutations in fruit flies?’ It seemed far-fetched that anyone would go to the trouble of doing that, rather than just dumping it at sea, but it wasn’t impossible. He wouldn’t necessarily have stumbled across the site; he hadn’t explored every last crevice on the island. The shift from the butterflies to all the other species could be due to a dramatic change in exposure levels: the drums might have split open after a few more years of weathering, or the land where they were buried might have subsided in a storm. Or maybe the poison had simply worked its way up the food chain. ‘The successful mutants thrive and breed, and some of the healthiest ones manage to cross to other islands. The only reason we’re not seeing any unfavourable mutations is because the afflicted animals are dying on the spot.’
Grant regarded him with undisguised irritation; she seemed genuinely reluctant to be drawn on the subject. But she wasn’t prepared to let this scenario go unchallenged. ‘Maybe you could explain the sheer number of genetic changes with a strong enough chemical mutagen, but the pattern still doesn’t make sense. Given everything else we’ve seen, some proportion of the animals who escaped from this hypothetical island should have had at least a couple of neutral alterations: changes to their anatomy or biochemistry that wouldn’t kill them or significantly disadvantage them, but which served no useful function at all. So far no one’s seen anything of the kind.’
‘Yes, but even the most “insignificant” disadvantage could be serious dead weight if you have to travel hundreds of kilometres just to be noticed. Maybe we’re only seeing mutants with changes that have been positively beneficial. I mean, you’d have to be pretty fit to fly all the way to Ambon from any of the remote islands in the south.’
Grant gave him an odd look. ‘They found a mutant tree frog in Ceram. That couldn’t have come from too far south—assuming it wasn’t hatched on the spot, which it might well have been.’ Ceram was a large island just ten kilometres north of Ambon. It was heavily populated around the coast, and parts of the interior had been logged and mined, but a considerable amount of rainforest remained intact. If Grant got it into her head to veer north and start traipsing through the jungles of Ceram, he’d never get anywhere near Madhusree’s expedition.
‘There are ferries running between the major islands,’ Prabir reminded her. ‘Something like a tree frog could have hidden in a crate of fruit, or even got on board a plane. Human transport can always complicate things to some degree.’
‘That’s true. But what makes you so sure that these animals have travelled at all?’
Prabir thought carefully before replying. Even if he’d known nothing about Teranesia, wouldn’t it be reasonable to suppose that there was an epicentre somewhere? He said, ‘If they haven’t, their parents or grandparents must have. If you follow the mutations back to their source, every animal must have had at least one ancestor exposed to the same mutagen at some point. I mean, whatever the cause, isn’t it stretching things to think that the same conditions could be repeated in half a dozen different locations?’
Grant shrugged. ‘You’re probably right.’ But she didn’t sound as if she meant it.
Prabir tried to read her face. If the animals weren’t travelling, what was? Any chemical spill severe enough to retain its potency across thousands of square kilometres could hardly have gone undetected this long. A hushed-up nuclear accident was even less plausible.
He said, ‘You think it’s a virus? But if it’s spreading all over the Moluccas, doesn’t that make it a thousand times harder to explain why we’re not seeing any unhealthy mutants? And isn’t it a bit far-fetched to think that it could infect so many different species?’
Grant gave him her sphinx impression. Prabir folded his arms and glowered at her. He wasn’t just killing time now: he was genuinely curious. He’d kept pushing the question aside as a distraction, but what Felix had called his cover story wasn’t entirely false: this was Radha and Rajendra’s life’s work, and part of him really did want to know what they would have discovered if they’d had the chance to complete it.
He said, ‘Unless the two mysteries are one and the same? Unless whatever makes the animals so impossibly successful makes the virus successful too?’
Grant said firmly, ‘We’ll gather some data, and we’ll see what we find. End of discussion. OK?’
Prabir lay on his bunk with his notepad’s headset on, brushing up on his Indonesian vocabulary. It was after midnight, but Grant was apparently still awake and busy. Most of the cabin was hidden from view by the row of lockers alongside the bunk, and the faint glow that diffused around them might have come from nothing but the phosphorescent exit sign, but whenever he took a break from his lessons he could hear the distinctive metallic squeaks of the ‘captain’s chair’. He had no idea what she was doing; with the collision avoidance radar and sonar switched on there was no pressing need for anyone to keep watch.
His concentration was faltering. He froze the audio and took off the headset. The humidity had become almost unbearable; the sleeping bag he was using as a mattress was soaked, and the air was so heavy that it felt as if he was drawing every breath through a straw. Maybe he’d be better off sleeping on deck, now that they were far enough out to sea not to worry about insects. The genetic quirk that had required him to be a walking mosquito killer as a child had no effect on the modern vaccine—another triumph for biotechnology, though when they reached some of the islands with undrained swamps he’d probably wish he still sweated repellent.