Representative insects known

Cyanogenic glycosides are formed in higher plants and some insects, e.g., Zygaena and Heliconius species. About 25 representatives are known today. 

Table V. Representative Microoi anisms and Insects Known to Digest Wool...

Perhaps the best known of these are the scale insects, family Coccidae (order Homop-tera), represented by the San Jose scale. This species has for many years been a serious pest of deciduous fruits. Another group within this family, the mealy bugs, are also susceptible to oil sprays. Oils used in control of these species are directed against the adults or partially grown forms. 

Two of the three attractant pheromones identified to date are very close structurally to those used in primary metabolism. The biosynthesis of the estolide 5 probably starts from 3-hydroxybutyric acid (4), an intermediate in fatty acid biosynthesis (Fig. 4.3). Condensation of two units furnishes the pheromone 5. The formation of cupilure (3 Fig. 4.2) can be easily explained by two methylations from ubiquitous citric acid. Both compounds are unlike any known insect pheromones, whereas the third known attractant pheromone (ketone 1 Fig. 4.1), bears some resemblance to some insect pheromones. A proper comparison of the differences and similarities between insect and arachnid pheromones will require the identification of representative compounds from most of the families of both groups of organisms. 

There are more species of Coleoptera than of any other order of insects. It has been estimated that over 350,000 species of beetles have been described, and this order represents about half of the total number of species (l). Thus it is somewhat surprising to discover from recent surveys of the literature (2,3) that pheromones have been identified for only about 50 to 75 species of Coleoptera. In contrast, sex pheromones or sex attractants (most of the latter discovered by screening procedures) are available for over 500 species of Lepidoptera. Furthermore, over half of the known coleopterous pheromones have been isolated and identified from species in the family scolytidae. 

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