Biology 2003 JAMB Past Questions - Question 10: An insect whose economic importance is both harmful and beneficial is the

Correct Answer

D

Explanation

Butterfly is beneficial because it pollinates flowers. The caterpillars of some species of butterflies, example silk worms produce silk of high quality. The caterpillars of some species of butterflies feed on crop pests called scale insects. Some species of butterflies have beautiful patterns and colours and are thus used as ornaments. The harmful effect is that caterpillars of some species cause destruction of crops and forest trees. Adult mosquitoes, tsetse flies and Simulium are only harmful. Various species of mosquitoes transmit disease causing organisms e.g. female anopheles transmit malaria parasites, aedesmosquito transmit yellow fever virus while culex transmits filarial worms that cause elephantiasis. Tsetse fly transmits trypanosome that causes sleeping sickness or trypanosomiasis while black fly (Simulium)transmits worm called On chocerca Volvolus which causes River blindness or Onchocerciasis