The Devil's Garden, By Edward Docx

'The Devil's Garden" is a name given by natives to clearings occurring sporadically in the Amazonian forest.

Entomologists know that these gaps in the dense foliage are made by ants which poison plants other than those in which they live.

This is the claustrophobic setting that the Geoffrey Faber Memorial prizewinner and Booker longlisted novelist Edward Docx plunges us into, while exploring corrupt South American politics. Dr J Forle is an entomologist on an expedition to study the extent to which these ants defy or conform to the "selfish gene" theory. (Ants are known to sacrifice their lives not only for their kin but also for unrelated colonies.) The idyll of his remote settlement is interrupted by the arrival of government officials, whose declared intent is to register the natives – comprising different tribes – for voting. But it becomes apparent that the laudable pursuit of democracy is far from their minds.

In twinning a zoologist protagonist with gripping drama, Docx is in respected company – with William Boyd, for example, and Jill Dawson. His allegory is clear: ants spend their lives labouring for the species' survival, but humans have little regard for each other. But Docx avoids simplistic condemnations: when Forle shows contempt for a cocaine baron's car, his lover witheringly dissects the reasons for the failure of Western eradication policies. And the grotesque chaos and death toll caused by competing trades – slavery, gold, arms, drugs, logs, rubber, sex – are illuminated in The Devil's Garden without stridency.

The story is narrated in the past tense by Forle, who is wracked by regret at not acting sooner. Docx dexterously conjures up the drought-stricken jungle: the suffocating, soupy atmosphere, fascinating wildlife and startling beauty. The palette of sky hues alone is spine-tinglingly beautiful: "wan and smoky blue"; "streaked in peach and pale vermilion"; "smudge of indigo and violet". And amid the feverish action are snippets of folk lore – one tribe believes that whites swarmed from the ground when locals were digging for metals.

Docx fleshes out his characters with wryly observed mannerisms. The cook is "constantly suspicious of a slight". Guide Felipe is obsequious, desperate for approval, a man who fills silences with inconsequential chatter. The missionary is given to "loosely binding his fingers before him ... as if on the cusp of prayer", and wearing shirts depicting skyward arrows and the words "I'm with Him".

As tensions mount and the camp's orderly routine unfurls into lawlessness, the surroundings become suffused with malignant foreboding – vultures strut; caiman and anaconda lurk. The escalating threat and the way in which a history of exploitation, hypocrisy and corruption breeds further immorality and violence, are reminiscent of novels by J M Coetzee or Damon Galgut. This poisoned Eden throbs with intensity, and delivers a gut punch that leaves you reeling.