Crustacea class

The phylum Arthropoda includes the classes Diplopoda (millipedes), Chilopoda (centipedes), Crustacea (see Chapter 3), and Insecta (see Chapter 1). All luminous arthropods other than crustaceans are terrestrial, and not very many luminous millipedes and centipedes are known. The luminescence of millipedes is usually intracellular, whereas luminous centipedes discharge luminous secretion. Substantial chemical studies have been made only with the millipede Luminodesmus sequoiae and the centipede Orphaneus brevilabiatus, of which the latter is discussed in the Section 10.3. 

The Class Arachnida, to which the order Acari belongs, together with the Class Insecta, the Class Crustacea and others, constitute the Phylum Arthropoda. All the classes contain species useful to man, but also many pests that can cause economic losses and/or diseases. This review will be limited to the order Acari, particularly to their control with natural methods in agriculture, veterinary and human medicine. 

Crustacean A member of the class Crustacea aquatic invertebrates with jointed appendages and having gills and two pairs of antennae. 

The Mandibulata is by far the largest group of arthropods, since it contains the insects. Animals in this group have two or three body segments, one or two pairs of antennae, and one pair of mandibles. The subphylum Mandibulata is divided into six classes, the largest two of which are the Hexapoda (insects) and Crustacea (crustaceans). 

Carotenoids of the Crustacea have attracted attention because of the colour that they impart to the animals. It is generally accepted that, like other animals, this class... 

K.C. Smith, E.R. Macagno (1990). UV photoreceptors in the compound eye of Daphnia magna (Crustacea Branchiopoda). A fourth spectral class in single omatidia. J. Comp. Physiol A, 166, 597-606. 

Arthropoda.—Steroid biosynthesis seems to be absent from all of this phylum. Examples of the class Arachnida, Diplopoda, Crustacea, and Insecta have been examined. Steroid metabolism in insects has been reviewed. " It should be borne in mind that insects can synthesise some terpenoids [e.g. (32) and (46)], but there is an absolute dietary requirement for steroids. Phytosterols such as -sitosterol are converted back into cholesterol derivatives apparently by the reverse of side chain alkylation (86 R = Et) (85 R = CHMe)—> (85 R = CHj)— (84)— (74). In addition a A -double bond is introduced. Parasites, and other organisms naturally present, may contribute to some of these reactions. ... 

The arthropods were the first organisms to emerge from the sea, and insects were the first invertebrates to fly. The arthropods consist of Crustacea (crabs, lobsters, shrimp, barnacles and woodlice), Chelicerata (spiders, ticks, mites, scorpions and others), Hexapoda or Insecta, and Myriapoda (millipedes, centipedes and other minor groups). These classes separated a long time ago, so they have developed quite differently, but it is interesting to discover parallel developments. 

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