Geoscience Reference
In-Depth Information
Many toads occur in Africa's rainforests. They vary in color; many blend in
well with the leaf litter or trees, making them almost invisible, while others can be
bright blue, green, or yellow. Toads range in size from tiny to large. Like frogs,
many toads are endemic and have limited distributions in forested areas. True
toads or Bufonids have been successful in both Africa and South America; Africa
is thought to be the origin of these toads with later dispersal into the Americas.
Caecilians are a small group of limbless amphibians that also live in the rainfor-
ests of Africa. They resemble worms or small snakes, with shiny skin. Caecilians
live in tropical rainforests across South America, Africa, and Asia, suggesting an
ancient distribution prior to the breakup of Gondwana. Caecilians typically live
below ground or in forest soils or leaf litter and feed on invertebrates.
Insects and Other Invertebrates
The majority of species in the world are invertebrates, yet they remain the least
studied. Insects as well as arachnids and crustaceans inhabit the rainforest. While
over a million species have been discovered, there are probably millions more to be
identified.
Beetles (order Coleoptera) are by far the most diverse order of insects in the
African rainforest. While new species continue to be discovered, tens of thousands
have yet to be described. Beetles range from 0.25-5 in (1-130 mm) in length. Many
have specialized niches. Many eat plants; others are associated with every kind of
decomposing matter, while others are parasitic. Some beetles convert wood into
dust, clean bones, spread pollen and seeds, enrich the soil, trim leaves and
branches, as well as provide a rich protein source for other animals. Scarab beetles,
including dung beetles, scavenge on waste and decaying matter. The Goliath beetle
is the largest of the African beetles.
Butterflies and moths (order Lepidoptera) are one group that has been well stud-
ied in the tropical rainforests of the world. The African rainforest is estimated to
house only half the number of butterflies found in the Neotropical or Asian-Pacific
rainforests, yet this diversity far outweighs that of all other terrestrial biomes. In the
African rainforest, 2,720 butterfly species have been identified. Moths have been
studied less than butterflies, so less is known about their species numbers, and life
histories. Together, more than 20,000 butterfly and moth species are estimated to
occur in the rainforests of Africa. Some butterflies take in nectar while others choose
fruit, dung, dead animals, and even animal perspiration as sources of nourishment.
The butterfly families that occur in abundance in the African rainforest include the
swallowtails, monarch butterflies, the brown butterflies, the whites, the blues, snout
butterflies, the nymphs, and the costers that are often brightly colored, unpalatable,
or poisonous. None of these families are unique to Africa. Butterflies in the swal-
lowtail family are the largest of the African butterflies. The African giant swallowtail
has a wingspan of 10 in (25 cm), only slightly larger than the giant blue swallowtail.
Termites (order Isoptera) are abundant in species, as well as total biomass in
the African rainforest. These social insects play a crucial role in maintaining
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