Teranesia

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.