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The Insects - Outline of Entomology 3th Edition - Chapter 14

Chapter 14 INSECT DEFENSE Although some humans eat insects (section 1.6), many “western” cultures are reluctant to use them as food; this aversion extends no further than humans. For very many organisms, insects provide a substantial food source, because they are nutritious, abundant, diverse. | TIC14 5 20 04 4 40 PM Page 355 Chapter 14 INSECT DEFENSE An African ant-mimicking membracid bug. After Boulard 1968. TIC14 5 20 04 4 40 PM Page 356 356 Insect defense Although some humans eat insects section 1.6 many western cultures are reluctant to use them as food this aversion extends no further than humans. For very many organisms insects provide a substantial food source because they are nutritious abundant diverse and found everywhere. Some animals termed insectivores rely almost exclusively on a diet of insects omnivores may eat them opportunistically and many herbivores unavoidably consume insects. Insectivores may be vertebrates or invertebrates including arthropods - insects certainly eat other insects. Even plants lure trap and digest insects for example pitcher plants both New World Sarraceniaceae and Old World Nepenthaceae digest arthropods predominantly ants in their fluid-filled pitchers section 11.4.2 and the flypaper and Venus flytraps Droseraceae capture many flies. Insects however actively or passively resist being eaten by means of a variety of protective devices - the insect defenses - which are the subject of this chapter. A review of the terms discussed in Chapter 13 is appropriate. A predator is an animal that kills and consumes a number of prey animals during its life. Animals that live at the expense of another animal but do not kill it are parasites which may live internally endoparasites or externally ectoparasites . Parasitoids are those that live at the expense of one animal that dies prematurely as a result. The animal attacked by parasites or parasitoids is a host. All insects are potential prey or hosts to many kinds of predators either vertebrate or invertebrate parasitoids or less often parasites. Many defensive strategies exist including use of specialized morphology as shown for the extraordinary ant-mimicking membracid bug Hamma rectum from tropical Africa in the vignette of this chapter behavior noxious chemicals and .