Charts & Graphs

Green Deals

Fair (and not so fair) exchanges in the natural world.

an ant.
a double-headed arrow.
a violet.

Violets produce fat blobs attached to their seeds called elaiosomes, which carnivorous ants harvest to feed their larvae. The seeds are discarded away from the parent plant’s shade, where they take root. In botany, the process is called myrmecochory, from Greek myrmex (ant) and chare (dispersal).

a douglas fir tree.
Douglas fir
a double-headed arrow.
a paper birch tree.
Paper birch

In summer, when coniferous trees compete with their leafy neighbors for sunlight, paper birches share nutrients and water with Douglas firs through a network of microscopic fungi at the trees’ roots. When winter arrives, the evergreen tree returns the favor, sending the necessary substances back to the birch.

lady's slipper orchid.
Lady’s slipper
a double-headed arrow.
a bee.

To reproduce, the lady’s slipper must first deceive a bee. The orchid emits a sweet scent as soon as it blooms, despite not yet producing any nectar. Bees attracted by the perfume become trapped inside the flower save for one exit under the flower’s stigma, making a pollen exchange inevitable.

a boxer crab.
Boxer crab
a double-headed arrow.
a Sea anemone.
Sea anemone

Certain Hawaiian species of boxer crabs (named for their tendency to punch opponents in territorial battles) grasp live sea anemones in their claws and use them as stinging boxing gloves. In return, the sea anemones, incapable of self-locomotion, eat their fill of the defeated foes.

a carrion beetle.
Carrion beetle
a double-headed arrow.
a mite.

Long-legged carrion beetles serve as transportation for some mite species, which hop aboard while the beetles are searching for food. The mites eat eggs laid by other carcass-devouring insects, thus improving the survival rate of beetle larvae.

a carpenter ant.
Carpenter ant
a double-headed arrow.
a Fungus-eating fungi.
Fungus-eating fungi

When Brazilian carpenter ants are killed by the parasitic fungus Ophiocordyceps unilateralis, their fellow ants often dump the corpses in a mass grave far away from the colony. This dumping ground attracts several species of hyperparasitic fungi that eat Ophiocordyceps—thereby preventing it from infecting more ants.