The Rainforest Canopy

INVERTEBRATES IN THE RAINFOREST CANOPY

Insects (pictures | news) are the most successful rainforest animals as demonstrated by their tremendous diversity. Insects are so ubiquitous that they have filled many niches usually occupied by other animals. For example, some postulate that in South America the role of the forest elephant is filled by leaf-cutter ants. In the rainforest canopy, insects abound: a study of the rainforest canopy in Peru with 500 cubic meters of foliage (about the size of a two-car garage) found more than 50 species of ants, 1,000 beetle species, 1,700 arthropod species, and more than 100,000 individuals. A rainforest tree alone can have some 1,200 species of beetle, while a single hectare of rich forest canopy is projected to have 12,448 beetle species.

There are many insects and other invertebrates that would not usually be considered arboreal but exist in the rainforest canopy. For example, several species of crabs have been found hundreds of feet above the ground in tank bromeliads of neotropical forests. Similarly, earthworms and giant planarians (flatworms) are also part of the canopy system, with earthworms playing an important role in the processing of canopy soils and mulch that supports epiphytic growth. Even leeches are found in the canopy where they may surprise first-time visitors to the Asian forest canopy. Mosquitoes, too, are abundant in the canopy, though on the ground there are generally few puddles for breeding and no pronounced seasonal changes to stimulate massive mosquito-breeding frenzy. In the canopy, mosquitoes lay their eggs in the up-turned leaves of epiphytes like tank bromeliads. Therefore, you may be more likely to get mosquito bites in the canopy than on the forest floor.

Many insects like stick insects, katydids, leaf hoppers, and mantids have developed incredible behavior, body structure, and color to mimic their surroundings. These insects, which mimic dead and living leaves, half-eaten leaves, sticks, bark, bird droppings, and flower parts, avoid detection by predators and prey as they hunt and rest.

Review questions:

• What is the most diverse group of creatures in the rainforest?

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