Insects attacking stored products

Parasitoid wasps are the most widely studied group of insect parasites. Female wasps lay an egg(s) on or in an insect and the progeny develop utilizing that insect as their sole food source, eventually killing the host. Female parasitoids tend to be host specific and typically exploit a specific host immature life stage (e.g., egg, larvae, or pupae). Most parasitoid wasps are relatively small. Females actively seek out multiple hosts and can find and parasitize host insects in cryptic habitats. There is a wide range of species that attack stored-product insects and a considerable body of research on these natural enemies, only some of which are covered here [see Godfray (1994) for more information on parasitoids and Brower et al. (1995) and Scholler and Flinn (2000) for reviews of information specifically on stored product parasitoids]. 

Insects such as mites, beetles and moths can attach any stored crude drug in the same way as they attack stored food. It is the larval stage which causes the damage to the product. 

Certain groups of secondary products protect animals against predation and microbial attack (Table 67). These substances may be either synthesized de novo in the animal body or are taken up with the food and are used directly or in a modified form. Some compounds are built, stored and secreted in special glands, e.g., the defense glands of insects and the skin glands of salamanders and toads. Others are constituents of blood or gut. Most of the toxins have a broad spectrum of activity against different kinds of predators or microorganisms. 

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