Lepidoptera, representative insects

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. 

Over the past four decades, extensive research on insect pheromones has resulted in the chemical and/or behavioural elucidation of pheromone components from over 1500 of the estimated 875,000 described species of insects [3-5]. Research on representative species within four orders Blattodea 4000 species Coleoptera > 300,000 species Diptera -150,000 species and Lepidoptera 150,000 species [5], shows the abundance and diversity of insects. 

Once consumed, allelochemics have assorted deleterious effects. Otherwise, they can pass through the insect with no effect, be sequestered, or detoxified. Many enzyme systems are involved in biochemical defense against plant allelochemics, but the most familiar and perhaps most important are the mixed function oxidases. Brattsten (1979) describes the three major characteristics that contribute to their importance in biochemical waste disposal (i) they catalyze numerous oxidative reactions that produce more polar and hence more excretable compounds, (ii) they are non-specific in that a wide range of chemicals are acceptable substrates, (iii) they can adjust rapidly (within minutes) to the presence of allelochemics or synthetic insecticides via induction. The MFO detoxification system is not confined to insects MFO activity has been identified in a wide range of vertebrates and invertebrates. A variety of flies, mosquitoes, cockroaches, crickets and a minimum of 40 species of Lepidoptera (as well as representatives from other insect orders) possess MFO activity (review Brattsten, 1979). 

Although the vast majority of the work on Batesian mimicry has been done on butterflies, it is by no means limited to this order. The following summary is meant to be representative, not exhaustive. Perhaps the best-known examples of Batesian mimicry outside of the Lepidoptera are those involving bees and wasps as models and other insects, especially flies, as mimics. The Browers (1960, 1962, 1965) have studied the reactions of toads (Bufo terrestris) to honeybees Apis mellifera) and their dronefly mimics Eristalis spp.) as well as to bumblebees Bombus americanorum) and their robberfly mimics Mallo-phora bomboides). 

Viral diseases have been isolated from several hundred insect species (1). Although these viruses represent several families, those studied for use as control agents are almost exclusively limited to occluded viruses (nuclear polyhedrosis [NPV] and granulosis [GV]) of Baculoviridae. Known occluded baculoviruses are mostly restricted to larvae of Lepidoptera and Hymenoptera (saw-flies), thus limiting viral insecticide development primarily to these two orders. These viruses are safe (2, 3), virulent, efficaceous (4) and can be produced in quantity in insect hosts. 

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