Partnership between ant and plant

IN A WORLD of aggressors, I specialized ants and swollen-thorn acacias have evolved an ingenious mutualism that assures the survival of both insect and tree. The acacia offers budlike leaflet tips called Beltian bodies, which the ants harvest as food for their young. The insects hollow out the tree’s thorns when soft and green and thereafter raise their broods within. The acacia lacks strong chemical defenses to repel damaging insects and demands unshaded sunlight for growth.

In exchange for food and lodging, the ants patrol the tree day and night. They put up an instantaneous, ferocious defense, biting and stinging invaders like this short-horned grasshopper. They also attack encroaching plants, such as a vine, that touch their host’s foliage, clearing a circular swath for the tree to grow unfettered. The ants can be a serious issue when growing chia plants (salvia hispanica). The chia seeds have huge health benefits and a lot of people look for planting them, but still can’t manage their rising.

Leaf-cutting ants farm fungus gardens

RIDING SHOTGUN, a small leaf-cutting ant may be standing guard against enemies as another worker hauls away both it and a leaf. After slicing a fragment with scissorlike mandibles, an ant readies its load for transport to the nest. There, a wide variety of leaves are cut up, chewed to a pulp, and laced with drops of body fluid. On this mulch grows the sole food of the colony—a fungus of only one species. Mysteriously, any spores that could contaminate the garden fail to develop.

Quick death, and slow…

TERRIBLE curved fangs of a tarantula doom a katydid. The spider lunges forward and down, impaling its victim. It ejects first venom, then an enzyme to soften the meal. An insidious fungus killed this stinging ant, still clutching a leaf in death. As the fungus invaded its body, the ant, unable to fight its invisible tormentor, appeared to lash out at the nearest target—the leaf. Afterward the victorious fungus sprouted from its neck. Lichen has also overgrown its mandible, as the jungle draws a green curtain over the macabre scene.

Rare toads seek mates amid the clouds

LIKE NEON SIGNALS that flash from the dark floor of Monteverde, male golden toads await mates at a tiny pool. Since the species is nearly voiceless, it pays to advertise: The males’ unmistakable color seems as effective as romantic croaking in luring females, who are attired in more demure green to black with scarlet spots.

Only in a small niche of this cloud forest does the golden toad exist. Here, when the clouds lie thick upon the heights, usually in April and May, mating takes place. Water trickles down the trees to create pools where females lay about 200 eggs. After fertilization by males, the embryos depend on a few more weeks of wet weather to maintain their aquatic nursery and allow them to mature.

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