Plant and Animal Interactions (Cont.)

Wasps

Wasp on fig, Ficus

Wasps play a crucial role in the lives of an important family of tropical rain forest plants, the figs (Ficus). Each species of fig has a single species of wasp which pollinates it. The female, laden with pollen, enters the young fig to lay her eggs in the ovules (where seeds form). In so doing, she pollinates the fig flowers. The young wasp larvae and fig seeds develop. When the young wasps emerge, they mate and the wingless males die. As the females crawl out of the fig, they are dusted with pollen which they carry to the next young fig where the cycle is repeated.

Bees

Euglossine bee with orchid, Gongora, flower

Flowers adapted to bee pollination are perhaps the major flower type found in the tropical rain forests. These flowers are usually brightly colored and possess guide marks which often are visible only in ultraviolet light. Bees, unlike humans, can see ultraviolet light and these markings help guide the bee to the nectar. The flowers also contain a "landing pad" or foothold for the bee. Several species of orchids mimic the appearance and scent of female bees and wasps and are pollinated when the male attempts to mate with the flower.

Flies

Fly on Aristolochia flower

In the tropical rain forests, dull brown, purple, yellow or spotted flowers that look and smell like rotting meat are pollinated by flies. Female flies are attracted to the "rotting meat" to lay their eggs and inadvertently pollinate the flower. Other flowers lure flies by smell or color and trap them. When pollination is complete, the flies are released (laden with pollen) to be trapped again elsewhere.

Beetles

Beetles on Dieffenbachia flower

As many as 30% of all species on Earth are beetles. In the tropics they are important pollinators. Beetles have poor eyesight, are clumsy, and have strong chewing jaws. They frequent flowers that give off a strong fruity or fermenting odor. Flowers pollinated by beetles produce copious petals, stamens and/or pollen upon which the beetles feed. The ovaries (where seeds are formed), are usually out of reach of the beetle's chewing jaws.

SEED DISPERSAL

Nutmeg

The fruits of the nutmeg tree are eaten by a bird, the Magnificent Bird of Paradise. The outer fruit is digested but the inner seed (the nutmeg) is protected by a thin hard shell. It passes through the digestive tract of the bird unharmed and is dispersed throughout the forest.

Brazil Nut

Brazil nut flowers are pollinated by several large- bodied bees, and the agouti (a large forest rodent) gnaws open the hard fruits and disperses the seeds. At present almost all of the world's supply of nuts are gathered in the forest, but plantation growing is beginning to yield results.

Durian

Durian is considered by many people to be among the world's finest fruits. Other people find it foul-smelling and unappetizing. Durian fruit is eaten and its seeds dispersed by tigers, who have a passion for the fruit. Gibbons, monkeys, pigs, tapirs and rhinoceros also disperse durian seeds.