Nowhere to hide Alarm as mass insect die-offs hit world's most protected areas

Daniel Janzen only began watching the insects – truly watching them – when his ribcage was shattered.

- Tess McClure

Daniel Janzen only began watching the insects – truly watching them – when his ribcage was shattered. Nearly half a century ago, the young ecologist had been out documenting fruit crops in a dense stretch of forest in Costa Rica when he fell in a ravine, landing on his back. The long lens of his camera punched up through three ribs, snapping the bones into his thorax.

Slowly, he dragged himself out, crawling nearly two miles back to the research hut. There were no immediate neighbours, no good roads, no simple solutions for getting to a hospital.

Selecting a rocking chair on the porch, Janzen used a bedsheet to strap his torso tightly to the frame. For a month, he sat, barely moving, waiting for his bones to knit back together. And he watched.

In front of him was a world seething with life. Every branch of every tree seemed to host its own small metropolis of creatures hunting, flying, crawling and eating. The research facility lay in a patchwork of protected rainforest, dry forest, cloud forest, mangroves and coastline covering an area the size of New York, and astonishingly rich in biodiverse life. Here, the bugs gorged, coating the leaf litter with a thick carpet of droppings.

But the real show was at night: for two hours each evening, the site got power and a 25-watt bulb flickered on above the porch. Out of the forest darkness, a tornado of insects would flock to its glow, spinning and dancing before the light. Lit up, the side of the house would be "absolutely plastered with moths – tens of thousands of them", Janzen says.

Inspired, he decided to erect a sheet for a light trap with a camera – a common way to document flying insect numbers and diversity. In that first photograph, taken in 1978, the sheet is so thickly studded with moths that in places the fabric is barely visible, transformed into what looks like densely patterned, crawling wallpaper.