From the Field Notes of Colonel Aubrey Fitch-Harrington, FRS

Observations Upon the Fauna of Southern Africa — Volume III (In Preparation)

“Roridula (Roridula gorgonias) is a carnivorous plant that does not digest its own prey. It traps insects on sticky tentacles but lacks the digestive enzymes to break them down. An assassin bug, Pameridea roridulae, lives exclusively on this plant. It eats the trapped insects. Its droppings fertilise the plant. The plant provides habitat and prey. The assassin bug provides digestion. Neither survives without the other. Roridula is, in this sense, not a predator but a landlord. The author notes that this is the most indirect feeding strategy he has encountered and that it required a specific moment of attention to understand that the plant was not eating anything directly, but had arranged for something else to eat on its behalf.”

He had been watching the plant digest for twenty minutes before he read the section on what it actually did.

The trapped fly was on the sticky tentacle. The plant had caught it. The plant was not digesting it. He had not looked closely enough to notice that nothing was happening to the fly in the digestive sense. He had looked at the trap and the prey and the mechanism and had moved to the next entry.

Then the assassin bug appeared.

Pameridea roridulae. Specific to this plant, found nowhere else, entirely dependent on what the plant provided. It walked on the sticky surface without sticking — the specific geometry of its feet preventing adhesion where the fly’s feet had not — and ate the fly and moved to the next trapped insect.

And its droppings went into the soil at the plant’s base.

And the plant used them.

He looked at the Roridula. At the assassin bug. At the arrangement.

“It has a sub-contractor,” he said.

“Yes,” Cetshwayo said.

“The plant cannot digest. So something else digests. And the plant —”

“Gets the result,” Cetshwayo said. “Without the mechanism.”

The fynbos around the Roridula smelled of resin and morning dew, the specific smell of the Cape floral kingdom going about its business at a scale the Colonel had been walking past. The plant was small. The assassin bug was smaller. The arrangement between them was as old as the plant’s current distribution, which was old enough.

The Colonel wrote: Roridula traps insects and cannot digest them. An assassin bug specific to this plant eats the insects and fertilises the plant with its droppings. The plant provides the trap, the habitat, and the prey. The bug provides the digestion. This is a carnivorous plant that outsourced the carnivorous part. The author has been watching what he thought was digestion for twenty minutes and was watching something considerably more interesting: an arrangement that makes both parties possible, achieved without any negotiation either party was aware of conducting.

He watched the assassin bug move to the next trapped insect.

He thought about the arrangement. The plant had a problem — it could catch but not process. The assassin bug had a solution. The assassin bug had a problem — it needed a reliable source of food and a surface to live on. The plant had a solution. Neither party had arrived at this by reasoning. They had arrived at it by being, over sufficient time, in proximity to each other’s needs.