Insect digestive enzymes: properties, compartmentalization and function

Acknowledgments ix Chapter 1: Introduction 1 Chapter 2: Coming Together 14 Chapter 3: Information Transfer 44 Chapter 4: Making Decisions 77 Chapter 5: Moving Together 101 Chapter 6: Synchronization 130 Chapter 7: Structures 151 Chapter 8: Regulation 173 Chapter 9: Complicated Interactions 198 Chapter 10: The Evolution of Co-operation 223 Chapter 11: Conclusions 253 References 259 Index 293

Collective Animal Behavior

▪ Abstract Control of grasshoppers and locusts has traditionally relied on synthetic insecticides, and for emergency situations this is unlikely to change. However, a growing awareness of the environmental issues associated with acridid control as well as the high costs of emergency control are expanding the demand for biological control. In particular, preventive, integrated control strategies with early interventions will reduce the financial and environmental costs associated with large-scale plague treatments. The recent development of effective oil formulations of Metarhizium anisopliae spores in Africa, Australia, and Brazil opens new possibilities for environmentally safe control operations. Metarhizium biopesticide kills 70%–90% of treated locusts within 14–20 days, with no measurable impact on nontarget organisms. An integrated pest management strategy, with an emphasis on the use of Metarhizium, that incorporates rational use of chemical pesticides with biological options such as the microsporid...

http://www.thethomaslab.net/uploads/lomer2001.pdf

Biological control of locusts and grasshoppers

The primary reason animals, including insect herbivores, eat is to acquire a mix of nutrients needed to fuel the processes of growth, development, and reproduction. Most insect herbivores strongly regulate their nutrient intake when given the opportunity. When they are restricted to imbalanced diets, they employ regulatory rules that govern the extent to which nutrients occurring in excess or deficit are eaten. Insect herbivores also regularly encounter allelochemicals as they eat, and recent work indicates the effect an allelochemical has on nutrient regulation, and insect herbivore performance, is modified depending on a food's nutrient composition. Comparative studies of nutrient regulation suggest coexisting generalist herbivores occupy unique nutritional feeding niches, and work with pathogens and parasitoids has revealed the manner in which top-down pressures influence patterns of nutrient intake. Insect herbivores regulate their nutrient intake using pre- and postingestive mechanisms, plus learning, and there is evidence that some of these mechanisms are shaped by natural selection.

Insect herbivore nutrient regulation.

Publisher Summary Among animal hormones, juvenile hormone (JH) is distinctive because of its unique structure and the diversity of its effects on insect development and reproduction. This chapter reviews the actions of JH on the fat body, gonads, accessory glands, muscle, and nervous system of adult insects. Whereas the epidermis is a major target of premetamorphic JH action, it has been studied little in adult insects, which generally do not moult. However, since the development of yellow pigmentation that accompanies sexual maturation in adult male locusts is clearly dependent on JH-regulation processes, in which cellular and molecular mechanism are investigated. The rapid recent progress in understanding how ecdysteroids regulate the gene activities has resulted from the opportunities afforded by drosophila melanogaster: mapped and characterized mutants, polytene chromosomes with puffs marking active genes, efficient germ-line transformation. The recognition of two aspects of JH action in the tissues of adult insects is reviewed. A model for understanding some aspects of priming by JH may be found in the action of ecdysteroids, where early genes produce factors needed for the expression of late genes. In structure, thyroxine is very different from JH, but there is considerable resemblance between thyroxine and phenoxyphenoxy carbamate, fenoxycarb. Functionally, there are marked similarities. Thyroxine governs metamorphosis in amphibians, but is remarkably pleiotropic in governing many processes ranging from the maturation of the central nervous system to thermoregulation. The chapter emphasizes the importance of selecting insect systems on the basis of their optimal features for research, rather than historical precedent or economic importance. With selection of appropriate systems and application of the cell and molecular research techniques now available, the elusive problem of JH action should soon yield to enlightenment.

G. C. Varley

Papers

Grasshoppers and Locusts