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Aquatic insects consume the stored air while under water or use it to regulate buoyancy. During a molt, air sacs fill and enlarge as the insect breaks free of the old exoskeleton and expands a new one. Between molts, the air sacs provide room for new growth—shrinking in volume as they are compressed by expansion of internal organs.
The strolling arthropods hypothesis was a very early hypothesis for the evolution of discontinuous gas exchange cycles. [2] It was postulated that discontinuous gas exchange cycles and spiracles which close off the respiratory system , may in part do so to prevent small arthropod parasites such as mites and particulate matter such as dust from ...
Aquatic arthropods generally possess some form of gills in which gas exchange takes place by diffusing through the exoskeleton. Others may breathe atmospheric air while remaining submerged, via breathing tubes or trapped air bubbles, though some aquatic insects may remain submerged indefinitely and respire using a plastron. A number of insects ...
In marine habitats, gastropods are preyed upon by fish, marine birds, marine mammals, crustaceans, and other mollusks such as cephalopods. In terrestrial environments, gastropod predators include insects , arachnids ( spiders , harvestmen ), [ 50 ] birds , and mammals , among others.
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.
Malpighian tubules are slender tubes normally found in the posterior regions of arthropod alimentary canals. Each tubule consists of a single layer of cells that is closed off at the distal end with the proximal end joining the alimentary canal at the junction between the midgut and hindgut. Most tubules are normally highly convoluted.
These minute arthropods are apterous, unlike some orders of insects that have lost their wings secondarily (but are derived from winged ancestors). Their mouthparts are enclosed within a pouch in the head capsule, called the gnathal pouch, so only the tips of the mandibles and maxillae are exposed beyond the cavity. [1]
Here, the vertex, or the apex (dorsal region), is situated between the compound eyes of insects with hypognathous and opisthognathous heads. In prognathous insects, the vertex is not found between the compound eyes, but rather where the ocelli are normally found. This is because the primary axis of the head is rotated 90° to become parallel to ...