It may be one of nature’s oddest couples: a tiny wasp that can barely be seen, and a giant fig tree, the sycomore, which shelters a remarkable menagerie of wildlife among its limbs. The wasp and the fig depend on each other for survival. Without the wasp, the tree could not pollinate its flowers and produce seeds. Without the fig, the wasp would have nowhere to lay its eggs.

The Queen of Trees shows this delicate dance of survival in exquisite detail, including spectacular close-ups of the wasp’s remarkable life inside a ripening fig. To capture such incredible images, filmmakers Victoria Stone and Mark Deeble spent two years camped out near a giant sycomore fig in Kenya’s outback, documenting the tree’s pivotal role as a source of food and shelter for everything from gray hornbills, Africa’s largest bird, to swarms of invading insects searching for food. In a surprising turn, some insects come to the tree’s aid — sparking a battle you won’t want to miss.

Online content for The Queen of Trees was originally posted April 2006.

To order a copy of The Queen of Trees, please visit the NATURE Shop.

Western yellow jackets, an invasive species, sting the camera lens during filming

Surrounded by ocean and formed by volcanic hot spots, Hawaii’s isolation and geological activity shape the biodiversity of the islands. With over 25,000 unique species, Hawaii is one of the most biologically diverse regions on the planet. A large percentage of these species are only found in the islands of Hawaii. While the number of species is impressive, these birds, insects, mammals, and plants live in a delicate balance.

As an isolated oceanic archipelago, the Hawaiian Islands offer insight into evolutionary processes that are unmatched in their beauty and complexity. Left to evolve on their own in the middle of the Pacific Ocean, Hawaiian species developed their own unique evolutionary traits. Each species’ survival depends on a host of other species, and when one species is lost the entire framework of Hawaiian ecology is disturbed. Unfortunately, Hawaii has the highest rate of extinction per square mile on Earth, and many endemic Hawaiian species are currently threatened or endangered.

Much of this crisis is a direct result of human colonization of the islands. Originally there were no mosquitoes or ticks, reptiles or amphibians, and the only mammals were the Hawaiian hoary bat and the Hawaiian monk seal. When humans came, they brought pigs, mice, lice, cockroaches, and a whole host of invasive plants. These invasive species have wreaked havoc on the Hawaiian ecosystem. To reach Earth’s most isolated archipelago, new species had to arrive either by air or by sea. Before humans stepped onto their shores, it is estimated that only about every 100,000 years did a new species glide down to the islands or wash up on the beach. This gave Hawaii’s ecosystem a lot of time to acclimate to each new species and incorporate each addition into the Hawaiian biome.

Today, it is estimated that new species are being introduced to Hawaii at a rate that is 2 million times more rapid than the natural rate. With international travel and the importing of goods, it is easier than ever for new species to be introduced. It is also more crucial than ever that new invasive species be kept off the islands. With so many native Hawaiian species endangered, and millions of dollars worth of crops at risk, the threat from invasive species is just too high. Besides rigorous screening at airports, scientists are taking new measures to ensure the survival of Hawaii’s vulnerable biodiversity.

The western yellow jackets (Vespula pensylvanica) seen in Kilauea: Mountain of Fire are not the only species of wasp reshaping Hawaiian flora and fauna. Since 2005, tiny orange wasps called Erythrina gall wasps have been decimating the wiliwili tree population, an endemic Hawaiian deciduous tree that grows up to 30 feet tall. Native to East Africa, the tiny wasps, about one-third the size of a mosquito, inject their eggs into the leaves of the wiliwili tree. The egg mass grows into a small lump or gall, which interferes with the tree’s ability to harvest sunlight and water. As a result the tree withers and dies. All over the islands of Hawaii, massive wiliwili carcasses dot the forests as well as the residential and agricultural areas. Besides providing habitat for Hawaiian wildlife, wiliwili trees have long been used as windbreaks. Planted in a straight line along the edges of crop fields, the wiliwilis protect the crops from wind damage. If the wiliwili trees die, so do the crops. It is predicted that if the gall wasp epidemic is not stopped, massive portions of Hawaiian forest will turn into desert.

To eradicate the gall wasps, scientists have no choice but to introduce another species of wasp to the Hawaiian islands: the Eurytoma wasp. These larger wasps inject their eggs into the Erythrina egg galls, where they develop more quickly than the smaller gall wasp species and hatch first. Once the Eurytoma’s hatch they feed on the unhatched Erythrina larvae. This keeps the gall wasp population numbers low, and will hopefully save the wiliwilis.

The first batch of 500 Eurytoma wasps were harvested in Tanzania near Mt. Kilimanjaro, and released into Honolulu’s Liliuokalani Botanical Gardens in November 2008. Scientists will have to keep a close eye on these foreign settlers. Hawaii has a long history of good intentions gone bad when it comes to introduced biological-control agents. The worst example is the mongoose, which was brought to the islands in 1883 by sugar cane farmers to control rat populations. Sadly, the mongooses primarily preyed upon Hawaiian birds and eggs, driving several species to near extinction and posing a major threat to endangered animals.

Another invader, the coqui frog from Puerto Rico, arrived in shipments of plants in the late 1980s. Featured in NATURE’s Animals Behaving Worse, male coqui frogs sound a loud mating call that annoys some of Hawaii’s human residents. But aside from being a nuisance to humans, some people worry that as the frogs advance throughout the islands, they may be setting the stage for other invasions. For example, frog-eating snakes, like the brown tree snake, could find a plentiful food source in the coquis. In Guam, the brown tree snake has done major damage, wiping out bird populations.

No one knows what will happen to Hawaiian biodiversity in the future, but perhaps hints can be found in the fiery nature of Hawaii itself. Every day, as fresh lava spills into the ocean, new land is formed—land that will someday be new habitat for Hawaiian plants and animals, both native and invasive. Just as the geography of Hawaii is always changing, so is the shape of life on these islands.

Remarkably, some plants have evolved a way to use caterpillar wasps to defend them from attack by hungry wrigglers. Here’s how it works: When a caterpillar bites certain plants, it leaves behind a drop of saliva that causes the plant to release chemicals of its own, called terpenoids. Like a silent scream or a chemical distress signal, the terpenoids warn the wasps that caterpillars are nearby. The wasps then flock to the plant, laying eggs on the vulnerable caterpillars. Several days later, the tiny wasp larva hatches anCaterpillar waspd begins eating the caterpillar alive.

Some wasps get a little help from a special virus in protecting their newly laid eggs. The “flying hypodermics,” as some scientists call them, injects the virus into the caterpillar along with the egg. It prevents the caterpillar’s immune system from attacking the egg. In return, the wasp supports the virus by providing a host. The only loser in the arrangement is the hapless caterpillar.

Other caterpillar wasps target caterpillar eggs, not the worms themselves, for egg laying. The tiny Trichogramma wasp, for instance, is only 1/50th of an inch long, but it can lay up to 300 of its own eggs inside caterpillar eggs. The Trichogramma larvae then feast on the caterpillar eggs. Farmers have enlisted this tiny ally in their effort to control pests, from peach borers to tent caterpillars, that would otherwise grow into adult caterpillars hungry for their crops.

Producer: Ronnie Godeanu
Art Director: Sabina Daley
Graphic Art: Lenny Drozner
Writer: David Malakoff
Technical Director: Brian Patrick Lee
Scientific Consultant: Gianna Savoie

Thirteen Online is a production of Thirteen/WNET New York’s Kravis Multimedia Education Center in New York City. Anthony Chapman, Director of Interactive & Broadband. Carmen DiRienzo, Vice President and Managing Director, Corporate Affairs.

© 1998 Thirteen/WNET New York

All Rights Reserved

Television Credits

A Co-Production of Thirteen/WNET New York and BBC-TV

Funder Credits

Funding for the TV series NATURE is made possible in part by Park Foundation. Major corporate support is provided by Canon U.S.A., Inc., Ford Motor Company, and TIAA-CREF. Additional support is provided by the nation’s public television stations.

For those interested in the subjects shown on SECRET GARDEN, we present the following Web sites. All links are valid as of December 21, 2000.

Biggs Wildlife Pond
http://www.sonic.net/~bigsnest/Pond/
Learn about the pond that Kathy and Dave Biggs created in their backyard and see pictures of the plants and animals it supports.

The Butterfly Zone
http://www.butterflies.com/
Tips on how to start your own butterfly garden, with links to a butterfly identification guide and the story of one man’s garden.

The Backyard Wildlife Habitat Program
http://www.nwf.org/backyardwildlifehabitat/
The National Wildlife Federation provides a wide array of resources for creating backyard habitats and understanding the plants and animals that live in them.

Smithsonian Butterfly Habitat Garden Homepage
http://www.si.edu/gardens/butterfly/
Extensive site detailing butterfly garden do’s and don’ts, as well as fascinating insights into the natural history of butterflies and plants.

Seed Savers Exchange
http://www.seedsavers.org/Home.asp
Web site of the organization that protects heirloom seeds, which can also be reached at the following address: Seed Savers Exchange, 3076 North Winn Road, Decorah, IA 52101.

Green Landscaping With Native Plants
http://www.epa.gov/greenacres/
Extensive site with practical advice from the U.S. Environmental Protection Agency.

Print Resources

For those interested in the secret life of the garden and gardening, we recommend the following books.

Bodanis, David. THE SECRET GARDEN: DAWN TO DUSK IN THE ASTONISHING HIDDEN WORLD OF THE GARDEN. New York: Simon & Schuster, 1992.

Capon, Brian. BOTANY FOR GARDENERS: AN INTRODUCTION AND GUIDE. Portland, Oregon: Timber Press, 1992.

Conrad, Jim. DISCOVER NATURE IN THE GARDEN: THINGS TO KNOW AND THINGS TO DO. New York: Stackpole Books, 1996.

Daniels, Stevie. THE WILD LAWN HANDBOOK. New York: Macmillan Publishing Co., 1995.

Druse, Ken, and Margaret Roach. THE NATURAL HABITAT GARDEN. New York: Crown Publishing Group, 1994.

Kress, Stephen W. THE BIRD GARDEN. London: Dorling Kindersley, 1995

Rogers, Marc, and Polly Alexander. SAVING SEEDS: THE GARDENER’S GUIDE TO GROWING AND STORING VEGETABLE AND FLOWER SEEDS. New York: Garden Way, 1991.

Schneck, Marcus. YOUR BACKYARD WILDLIFE GARDEN. New York: Rodale Press, 1992.

Schultz, Warren. THE CHEMICAL-FREE LAWN. New York: Rodale Press, 1989.

Stein, Sara Bonett. PLANTING NOAH’S GARDEN: FURTHER ADVENTURES IN BACKYARD ECOLOGY. New York: Houghton Mifflin, 1997.

Swain, Roger. EARTHLY PLEASURES: TALES FROM A BIOLOGIST’S GARDEN. New York: Lyons Press, 1994.

Tufts, Craig, and Peter Loewer. THE NATIONAL WILDLIFE FEDERATION’S GUIDE TO GARDENING FOR WILDLIFE. New York: Rodale Press, 1995.

Xerces Society Staff. BUTTERFLY GARDENING. San Francisco: Sierra Club Books, 1990.

Many plant varieties are disappearing.

In addition to providing havens for wildlife, backyard gardeners can also play an important role in saving some plant varieties from extinction. Over the last few centuries, farmers and gardeners have given up many traditional food crop varieties in favor of new, hardier varieties that are easier to grow and ship.
United States, for instance, has shrunk from more than 7,000 to fewer than 2,000 — and less than a dozen types make up the bulk of what is available in stores. Similarly, farmers in North and South America once grew thousands of tomato varieties; today, most have been lost or exist as seeds stored by elderly gardeners.

To save these often tasty and beautiful “heirloom” varieties, an increasing number of dedicated gardeners are growing these threatened plants and sharing the seeds with others. These “seed savers” have rescued hundreds of varieties, including many that are considered culinary superstars. Two leaders of this grassroots conservation movement are Kent and Diane Whaley of the nonprofit Seed Savers Exchange in Decorah, Iowa . The couple founded the Exchange in 1975 after an elderly, terminally-ill relative asked them to safeguard precious garden seeds brought from Bavaria four generations earlier. Today, the Exchange protects more than 13,000 endangered vegetable varieties, 700 old-time apples and 200 hardy grapes.

Plant breeders believe some of these old varieties hold genes that will allow them to create new, tastier crops that resist drought and disease, and require fewer chemicals. So far, 1,000 people across the country have joined the Seed Savers Exchange, using the organization’s newsletter and periodic meetings as a central clearinghouse for sharing information on growing treasured varieties and swapping rare seeds. The group also publishes a catalog and other materials that explain where to find heirloom varieties and how get started in seed saving. To become a conservator yourself, contact the Seed Savers Exchange. A winner of one of the MacArthur Foundation’s “genius grants” for his seed-saving work, Kent Whaley believes that gardeners committed to saving these seeds are providing insurance for the future. “It’s genetic treasure,” he says.

You can easily lure wildlife to your garden.

Growing a garden with plenty of nooks and crannies for critters isn’t that difficult. So says the National Wildlife Federation’s Heather Carskaddan, who has helped create more than 20,000 wildlife-friendly yards through the group’s Backyard Wildlife Habitat Program. “You need four key elements in your garden to attract wildlife,” she explains. “Animals need food, water, cover, and places to raise young.”

To feed the animals, one should plant species that produce flowers, fruits, nectar, nuts, and seeds at different seasons. Be aware that some animals prefer specific plants. Goldfinches, for instance, are attracted to thistles and other seed-bearing flowers, while hummingbirds prefer bright, nectar-rich flowers, such as columbine, bee-balm, and trumpet vine. Butterflies can be particularly picky, says naturalist Craig Tufts of the National Wildlife Federation: “Native butterflies have very limited food preferences, but if you put the right plant out it’s like a beacon.” Monarch butterflies, for instance, prefer laying their eggs on milkweed, because that is what they eat at their caterpillar stage. For gardeners not sure where to start, many commercial suppliers now package seed combinations geared toward attracting butterflies, birds, and even bats.

A water source like a birdbath, dripping hose, or even a puddle can be enough to slake the thirst of birds and butterflies, but if you really want an adventure, Tufts says, build a small pond in your backyard. “It surprises people how fast a water garden is colonized — it’s as if the dragonfly larvae and frogs parachute in,” Tufts says. “You wake up one morning and discover a chorus of breeding toads.” Sometimes, providing good cover for wildlife means being what some people might consider a messy gardener. Cavity-ridden dead trees, brush piles, and tangled bushes can all provide much-needed homes to some species, but too often, gardeners clean them out in favor of a tidy appearance. For those in cold climates, planting evergreens can provide winter shelter not offered by trees and bushes that lose their leaves.

A lawn provides poor cover for most animals.

Carskaddan encourages wildlife gardeners to use plants native to their area. Animals recognize these plants, “and since they are adapted to your region, you can use fewer chemicals and less water” as you garden, she says. She also urges gardeners to reduce both their use of pesticides and the size of their grass lawns as much as possible. “[Lawns] are considered biological deserts because they are single-species monocultures,” she explains. “By getting more creative, you can provide different levels of cover for everything from tiny voles to larger birds.”

Biologists caution that some animals are simply unable to adapt to life around people, such as warblers that require quiet, mature forests or salamanders that need a large, moist habitat. Even the most wildlife-friendly garden won’t be able to attract these creatures. In fact, scientists note that the most common garden life — weeds, crop-eating insects, and birds that thrive near structures — tend to be generalists, able to feed and nest in a wide variety of areas. Some go as far as to call these highly-adaptable organisms “weed species,” because they can thrive almost anywhere. “Weeds” or not, the average gardener generally welcomes the sight of brilliantly-hued cardinals and blue jays feeding in his backyard.

In addition, researchers say, a wildlife-friendly garden can help discourage many unwanted pests, like plant-eating aphids, by attracting the insects’ natural predators. “One of my favorite examples is what can happen when gardeners don’t spray pesticides,” says Tufts, who notes that although chemicals do get rid of unwanted pests like aphids, they also kill the insects’ natural predators, who may do the job more effectively. After gardeners who decide to shun pesticides stop using them, Tufts says, aphid populations may increase at first, “but soon a whole army of predators arrives, from ladybugs and lacewings to serpentflies and mummy wasps. Most people can’t believe that all these things are suddenly eating aphids — and all kinds of other pests, too!” he adds.