| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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HERE AT THE ACADEMY The Academy's Ant Invasion
Letters often arrive at the California Academy of Sciences addressed to the Department of Antomology. The chief AntMan, Brian Fisher, for whom these missives are usually intended, is actually an entomologist, or more specifically, a myrmecologist. Recently, he combined his expertise with that of the Exhibits Department to create, in the Academy’s new Howard Street facility, windows into the world of ants. A highlight of this striking exhibit will be the largest ever captive colony of army ants. These legendarily ferocious creatures build living nests out of their own bodies, bivouacking wherever the plunder is good. In the bivouac, the queen and young are held by adult workers who make up a brood chamber well protected by the slashing jaws of the soldiers. The colony, comprising roughly a half-million individuals, is expected to devour 3,000 crickets per day. Visitors will be able to watch the feeding process. A keeper will enter the ant enclosure three times a day, lure the ants from their bivouac area by dropping mealworms, and then release crickets to the hungry horde. Although an exciting spectacle, the army ants are only one part of the Howard Street Ant Exhibit. Visitors will be greeted by virtual swarms of ants projected onto the wall panels, then enter an “ant tunnel” lined with sculptured ants and amazing ant facts. The tunnel opens into the “nest,” along with casts of ant nests, close-ups of ant anatomy, dioramas showing the environments in which ants thrive, and a slideshow emphasizing the diversity of the ants themselves. From the seed-harvesters of arid grasslands to the leafcutters of tropical forests, ants are found in every continent except Antarctica and are probably the most successful organism on earth. There will also be five other live colonies of ants—four from California and one more from the tropics. Of the California species, three are natives and one is an invader. Honeypot ants from the Mojave Desert will live in a huge, illuminated nest. This species herds aphids, which they “milk” to gather sugary honeydew. Workers transfer the food to the colony’s living stomachs, ants known as repletes, whose alarmingly swollen bodies hang from the ceiling. Their only duty is to store the colony’s food. When workers get hungry, they lock jaws with the repletes to top up their tanks. In turn, workers share the nourishment with peers and their queen, in a process known as trophollaxis. If honeypot ants are herders, leafcutter ants are farmers. Common in Central and South America, these ants snip bits of leaves and flowers and add the vegetation to carefully tended beds of compost The ants inoculate this compost with the spores of fungi and, like mushroom farmers, harvest the fruiting bodies to eat. There are also ants that neither farm nor herd, but rely on nature’s bounty. But the native seed-harvesting ant, common in oak savanna biomes, is losing out in a big way to the invasive Argentine ant. Their disappearance now threatens the California horned lizard with extinction. Unwilling to eat the hard, sour bodies of aggressive Argentines, the horned lizard now has a tough time finding enough food to eat. The ants’ other advantage is large numbers. There is only one supercolony of Argentine ants in all of California. It stretches from Oregon to San Diego and is continually expanding. It is not only horned lizards and anteaters that eat ants. Another exhibit shows the enormous numbers of creatures that depend on ants for food—including people. In many parts of the world, ants—usually as larvae or pupae—provide a welcome protein supplement to human diets. Plants too form symbiotic relationships with ants, like the acacias which offer hollow thorns to house ants in exchange for security services. Research and public outreach at the Academy are now closely intertwined, and learning flows both ways. Scientists like Fisher, who literally scour the world in search of specimens, provide new information. Intrigued visitors and teachers receive research kits which enable them to identify and record the neighborhood’s ants. Their data will be fed back to the Academy where a map will be made of the ants of the Bay Area—a project never before attempted. The data will also be fed into Antweb (http://www.antweb.org), Fisher’s ambitious groundbreaking project to provide ant taxonomic data on the Internet. Information generated from Antweb comes back to the Academy, with value added. It’s a wonderful symbiosis: armies of scientists and citizen scientists, foraging and working as busily as the armies of ants that inspired this exhibit. Suzanne Ubick is Assistant Editor of California Wild. |
