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Isopoda is an order of crustaceans.Members of this group are called isopods and include both aquatic species, and terrestrial species such as woodlice.All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration.
Paired, mobile, and segmented, they are located between the eyes on the forehead. Embryologically, they represent the appendages of the second head segment. [8] All insects have antennae, however they may be greatly reduced in the larval forms. Amongst the non-insect classes of the Hexapoda, both Collembola and Diplura have antenna, but Protura ...
In the past, the term insect was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arachnids, myriapods, and crustaceans. The field is also referred to as insectology in American English, while in British English insectology implies the study of the ...
Differences between instars can often be seen in altered body proportions, colors, patterns, changes in the number of body segments or head width. After moulting, i.e. shedding their exoskeleton, the juvenile arthropods continue in their life cycle until they either pupate or moult again.
Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill , or function essentially as normal, via a plastron .
Differences may include secondary sex characteristics, size, weight, color, or markings, as well as behavioral and cognitive differences. In the butterfly species Colias dimera (also known as the Dimera sulphur), seen here mating in Venezuela, the male on the right is a brighter shade of yellow than the female.
An intriguing arthropod ancestor. The 3D scans revealed two nearly complete specimens of Arthropleura that lived 300 million years ago. Both fossilized animals still had most of their legs, and ...
The winged insects are nocturnal and provide food for night-flying birds, bats, small mammals, amphibians and arthropods. The larval stage lasts much longer, often for one or more years, and has a bigger impact on the environment. [20] They form an important part of the diet of fish such as the trout. The fish acquire them by two means, either ...