Summer 1998

Stroking
Words by Stephen Packard. Photos by Ron Panzer.

The three species in this photo are engaged in an ancient ritual. The camouflaged caterpillar, as it eats rare flowers, is attended by ants. Soon the ant on the back of the pink caterpillar will begin to stroke it. Something wonderful is in process.

The fat caterpillar would tempt many an insect predator, were it not for the ants that guard it. Nice ants, huh? Yet these are also selfish ants, perhaps even addicted ants. They softly brush that larval body with their antennae, they caress it, and it reciprocates by producing droplets of a fluid that the attendants devour greedily. Yes, an intimate relationship proceeds in these rare flowers.

Many of the gossamer-winged butterflies — the coppers, the blues, the hairstreaks — have co-evolved with certain ants to supply each others' needs. The butterfly caterpillar makes substances that are highly sought-after by the ant, and the ants ward off parasites and predators that would otherwise eat the future butterfly. When full and fat, the caterpillar may head down into the thick of the ant's underground nest to pupate, overwinter, and emerge as a butterfly the following spring.

What does the plant get out of this? Perhaps nothing, but perhaps the ants protect it too. Ants do protect many plant species that provide them with special services. When ants were experimentally removed from certain other plant species, the plants were consumed utterly by hordes of herbivores the ants had fended off.

This caterpillar is the larva of the silvery blue — a butterfly thought extinct in Illinois until the 1980s. At that time, interest in re-discovering the savanna inspired biologists to look in new places. Where botanists found remnant populations of savanna flora, ornithologists found rare birds, mycologists found rare mushrooms, and lepidopterists found rare butterflies.

The silvery blue was rediscovered by Ron Panzer at Wadsworth Savanna, a site first identified by botanists for its rare plants, like the veiny pea which the rare caterpillar was busily eating. The Lake County Forest Preserve District bought the land, and restoration management began.

That's conservation. Without it we lose species, but "species loss" sounds so thin. What's really lost is millions of thriving lives. The fragrances, the bird calls overhead, the stroking. Millions of years of evolution thrive in Chicago Wilderness. Conservation saves the ancient drama, and keeps its life fresh with ours.