Insect behavior and development

Volatile isoprenoids that control insect behavior and development have been reviewed.476 Information on the biosynthesis of terpenoids with special emphasis on beetle pheromones has been compiled by Seybold and... 

The first section. Bioregulation of Insect Behavior and Development, includes chapters on arthropod and insect repellents, the identification of a beetle pheromone, nonparalyzing factors fi om hymenoptera, endogenous regulation of pheromone biosynthesis and mating, and systems for controlled release of pheromones. 

Most previous experiments with kauranes and closely related compounds have been concerned with their effects on Insect growth and development. However in this case the deterrent effects of the Isolated compounds to Trirhabda canadensis were investigated as a first step in understanding the feeding behavior of this insect in the field. 

Phytoecdysones, due to their effects on the behavior and the development of certain species of Insects, appear to be components of multichemical defensive strategies found In some Insect-resistant plant species ... 

Most of the present book is dedicated to one class of Arthropoda, the Insecta, because chemical communication research in this class is the most complete and broadly illustrated. This type of research on the chelicerate arthropods of the class Arachnida is, by contrast, poorly developed. We saw for example in Chapter 7, studies of chemical ecology interactions with Acari and particularly mite-insect interactions, and a few examples of chemical interaction with spiders were also shown in the same chapter on chemical mimicry, even though spiders are the most familiar and numerous of the arachnids. We undertook some work and about 15-10 years ago on contact chemical signal description and its relationship with behavior, physiology and reproduction, in different types of Aranea (spiders). We will present here a distillation of this work with a review of studies on the subject by different authors. Most notable here is the poverty of research on contact recognition signals and relative behavioral works on the order Scorpionida, the scorpions. Some of the few chemical data available are published here for the first time. 

We are also unable at the present time to sample and analyze many pheromone chemicals at any concentration - let alone the low biologically active levels - because of their instability upon the sampling media for the time they must remain there. Extension of our sampling and detection and analysis techniques to much lower levels presents another major research challenge. At the present time this is the main obstacle to progress, Beyond this point it is possible to foresee the development of a major research area in future which will contribute to large strides in the techniques of controlling insect populations and insect behavior. 

Insects are so successful because of their mobility, high reproductive potential, ability to exploit plants as a food resource, and to occupy so many ecological niches. Plants are essentially sessile and can be seen to produce flowers, nector, pollen, and a variety of chemical attractants to induce insect cooperation in cross-pollination. However, in order to reduce the efficiency of insect predation upon them, plants also produce a host of structural, mechanical, and chemical defensive artifices. The most visible chemical defenses are poisons, but certain chemicals, not intrinsically toxic, are targeted to disrupt specific control systems in insects that regulate discrete aspects of insect physiology, biochemistry, and behavior. Hormones and pheromones are unique regulators of insect growth, development, reproduction, diapause, and behavior. Plant secondary chemicals focused on the disruption of insect endocrine and pheromone mediated processes can be visualized as important components of plant defensive mechanisms. 

The overall importance of octopamine in insects is emphasised by the destructive influence of the formamidines and PIIs. Thus octopamine orchestrates appropriate behaviors and "prepares" the insect for stressful conditions. It mediates a "flight or fight" response. Disturbing octopamines homeostasis results in behaviors occurring at inappropriate times. Clearly a complete understanding of octopamine in insects may well lead to the development of... 

Practical implications of a full elucidation of biochemical bases of insect resistance in plants are tremendous. Identification of the chemicals that confer resistance or susceptibility, and study of their inheritance in crop plants, would greatly improve breeding for resistant varieties. If resistance involves more than one defense chemical, it may be possible to develop a relatively stable type of resistance since pests are not likely to overcome sensitivity to several substances simultaneously. It would also open new avenues for manipulation of insect behavior for use in pest management programs. 

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