Insect orders

Carboniferous 345 Myr Climate cools, marked latitudinal gradients. Extensive forests of early vascular plants, especially club mosses, horsetails, ferns. Coal beds form. Amphibians diversify first reptiles appear. Radiation of early insect orders... 

Abstract Hymenoptera is a very large and diverse insect order that includes the majority of both the social and the parasitic insects. With such diversity comes a variety and complexity of semiochemicals that reflect the varied biology of members of this order. This chapter reviews the chemical identification of pheromones and semiochemicals in the order Hymenoptera since 1990. For this review, the species in Hymenoptera have been classified as solitary, parasitic, or social. The chemical diversity of semiochemicals in Hymenoptera and future trends in pheromone identification are also discussed. 

Unlike parasitoids of other insect orders that have host-seeking larvae, most parasitic hymenoptera lay their eggs on, in, or very close to a host individual [11]. This requires the adult female to find a suitable host, often with the aid of chemical cues from host frass, pheromones, plant volatiles emitted upon host feeding or egg-deposition, silk, honeydew and other secretions. She may then chemically mark the host following oviposition to reduce superparasitism by herself or intra- and inter-specific insects [11]. 

The repertoire of chemicals that can be used for communication is limited by the biosynthetic ability of the insect. Compared to other insect orders, pheromone biosynthesis in Hymenoptera has received little study [191]. However, the biosynthetic origins of chemically diverse hymenopteran semiochemicals likely include aromatic, fatty acid, and terpenoid pathways as well as simple modifications of host-derived precursors. Notable recent studies include the biosynthesis of the fatty acid components (2 )-9-oxodec-2-enoic acid 52 and (2 )-9-hydroxydec-2-enoic acid of the honeybee queen mandibular pheromone from octadecanoic acid [192,193], and the aliphatic alcohol and ester... 

With adequate resources and effort, the tools are available to chemically identify many more semiochemicals in Hymenoptera. Much is still to be understood about the chemically-mediated communication in this large and diverse insect order. In addition,because many hymenoptera are significant beneficial or pest insects, and the use of semiochemicals in the management and monitoring of insects is becoming standard, the identification of additional semiochemicals in Hymenoptera is an economically worthwhile endeavor. 

OBPs were initially identified in Lepidoptera and later isolated and/or cloned from various insect orders, namely, Coleoptera, Diptera, Hymenoptera, and Hemiptera ([16] and references therein). Recently, they have been identified from a primitive termite species [ 17], thus, suggesting that this gene family is distributed throughout the Neopteran orders. The three orders most... 

Beetles (Coleoptera) comprise the most species-rich insect order. About 350,000 species have been described today, about 10% of the estimated actual amount. Apart from open oceans, beetles are colonizing almost every habitat and are able... 

Continuous insect cell lines were first established in culture over three decades ago when Grace [45] succeed in growing cells from female Antherea eucalypti moth ovaries. Since Grace s first report on four cell lines, over 400 lines have been established from more than 100 insect species representing every economically important insect order [46,47]. 

Among the insect orders, tissues from Lepidoptera have attracted the most attention because of their historical importance as agricultural pests [48]. Insect cell lines have been established from a variety of tissues, mostly from undifferentiated ovarian or embryonic [49]. The undifferentiated nature of the embryonic tissue has made possible the establishment of continuous insect celllines from diploid tissues [49]. 

Different subspecies have been shown to be active against different orders of insect. Although the method of insect death is the same, the different endotoxins either have different binding regimes or are activated by the gut enzymes of different insect species and this leads to the differences in activity spectrum. There is evidence, however, that different insect orders act upon the delta-endotoxins in different ways. Treatment of a pro-toxin with lepidopteran gut juice leads to a toxin that is active against Lepidoptera whereas treatment with dipteran gut juice produces... 

Vogt R. G., Callahan F. E., Rogers M. E. and Dickens J. C. (1999) Odorant binding protein diversity and distribution among the insect orders, as indicated by LAP, an OBP-related protein of the true bug Lygus lineolaris (Hemiptera, Heteroptera). Chem. Senses 24, 481 —495. 

Whiting M. F., Carpenter J. C., Wheeler Q. D. and Wheeler W. C. (1997) The Strepsiptera problem phylogeny of the holometabolous insect orders inferred from 18S and 28S ribosomal DNA sequences and morphology. Systematics Bulletin 46, 1-68. 

OBPs have now been identified from numerous species of several insect Orders, including Lepidoptera, Diptera, Coleoptera and Hymenoptera (holometabolous insects), as well as Hemiptera and Phasmatodea (ametabolous insects). A recent classification defining OBP-Typel and OBP-Type 2 has been proposed by Vogt et al. (1999), based on phylogeny, tissue localization and structural features. 

Insect order Species Protein name Database Reference... 

Recently, comprehensive World Wide Web (Internet) databases have been established on insect pheromones and semiochemicals The Pherolist , a database of chemicals identified from sex pheromone glands of female lepidopteran insects and other chemicals attractive to male moths (Am et al., 1999) and The Pherobase , a database of pheromones and semiochemicals for Lepidoptera and other insect orders (El-Sayed, 2006). These large databases on behavior modifying chemicals have extensive cross-linkages for animal taxa, indexes of compounds and source (reference) indexes. The indexes include those compounds cited in this chapter and many more with pheromone and semiochemical function acetate esters, diols, epoxides, ethers, ketones and secondary alcohols. For example, The Pherolist reports approximately 90 epoxy derivatives of C17-C23 of n-alkancs, mono-alkenes and di-alkenes as insect semiochemicals. 

---