Arthropod development

A detailed summary of the roles of ecdysteroids during arthropod development and reproduction is beyond the scope of this review. This aspect has been extensively reviewed elsewhere [1,2,6-9],... 

Personal protection is usually associated with the use of products and devices to stop bites, but one of the first steps an individual should take is to attempt to limit the source of the problem. Of course, such measures are only possible at fixed locations where sources of biting arthropods can be modified or eliminated. Home pest control is beyond the scope of this book, but certain measures are so important that they cannot be ignored as part of best practices for personal protection. General insecticide application will often provide relief from many different kinds of arthropods regardless of their sources, but certain problems can be eliminated, or nearly so, by removal of sources where the arthropod develops. 

Since persistence in sediments is longer than that in the water column, the relevant toxicity studies are those that consider longer term, chronic exposures. A number of standard tests have been developed for assessing sediment toxicity and the bioassay of field collected sediments (e.g., [16-24]). The most commonly tested freshwater species are arthropods, including the amphipod shrimp // azteca and chironomid midge larvae, both Chironomus dilutus (formerly C. tentans) and C. riparius. Water-only studies have demonstrated that II. azteca are particularly sensitive to SPs (see Sect. 3) and in the published literature, this is the most commonly tested species for assessing the sediment toxicity of SPs. 

The microorganism was classified as a new species of actinomycete. Streptomyces avermitilis. Its anthelmintic activity was shown to reside in 8 closely related macrocyclic lactones, named avermectins, which were also found to possess activity against free-living and parasitic arthropods. One of the natural components, avermectin is now being evaluated as a pesticide for the control of mites of citrus and cotton crops and control of the Red Imported Fire Ant. A chemical derivative, 22,23-dihydroavermectin or ivermectin, has been developed as an antiparasitic agent. It is being marketed for use in cattle, horses and sheep and is expected to become available for swine and dogs. 

The known and postulated actions of OA in arthropods have been the subject of several recent reviews (8 9 12t13) and will be mentioned here only in as far as it helps to indicate the kinds of responses which may occur when octopaminergic drugs are presented to an arthropod, and how some of these responses may be utilized to develop assays for the discovery and evaluation of such agents. 

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