The mandible (from or mandĭbŭ-lum, a jaw) [Latin Dictionary Founded on Andrews' edition of Freund's Latin dictionary revised by Charlton T. Lewis, Ph.D. and. Charles Short, LL.D. Oxford. Clarendon Press. 1879.] of an arthropod is a pair of mouthparts used either for biting or cutting and holding food. Mandibles are often simply called jaws. Mandibles are present in the extant subphylum Myriapoda (millipedes and others), Crustacean and Hexapoda (insects etc.). These groups make up the clade Mandibulata, which is currently believed to be the sister group to the rest of arthropods, the clade Arachnomorpha (Chelicerata and Trilobite).
Unlike the chelicerae of , mandibles can often be used to chew food. Mandibulates also differ by having antennae, and also by having three distinct body regions: head, thorax and abdomen. (The cephalothorax (or prosoma) of chelicerates is a fusion of head and thorax.)
Insects
Insect mandibles are as diverse in form as their food. For instance,
and many other plant-eating insects have sharp-edged mandibles that move side to side. Most
Lepidoptera lack mandibles as they mainly feed on nectar from flowers.
have mandibles with sharp cutting teeth unlike , who have toothless jaws. Male Dobsonfly have slender mandibles up to 2.5 cm long, half as long as the insect's main body. use their mandibles to mix droplets of water with clay while constructing a nest.
Ants
have long, broad, serrated jaws, used for digging, collecting food, fighting and cutting, and are probably the most important work tool ants possess. Ants typically bite each other when fighting. Some ants use mandibles to injure the enemy and squirt poison into the wound.
use their mandibles to collect and carry seeds.
have sharp mandibles that are better adapted for fighting than obtaining food or nursing the
.
make their nests in various wooden structures, which they hollow out with their sharp mandibles.
Beetles
The shape and size of
beetle mandibles varies from species to species depending on the food preferences. For example,
Carnivore beetles have extended mandibles to seize or crush prey.
' mandibles (similar to the piercing canine teeth of tigers) are well adapted for killing prey.
Dytiscidae and
firefly larvae have hollow mandibles, which can inject digestive fluid to
Liquification the tissues of the prey. When this process is over, they suck the digested tissue through the mandibles.
The jaws of stag beetles are essentially their namesake trait. In some tropical species they can be up to 10 cm, as long as the body of the beetle. These mandibles are primarily used in combat.
Butterflies and moths
use sharp mandibles to cut leaves in side-to-side motions. Only a few
have functional mandibles in the adult stage. The most notable example are members of the family
Micropterigidae, small moths with toothed mandibles used for chewing
pollen grains, lacking even the most rudimentary
proboscis.
Myriapods
Among
myriapoda,
have strong, bristly mandibles, which have a row of teeth in all centipedes except for members of the order Geophilomorpha. Millipedes have small mandibles, their only functioning mouthparts, as the maxillae are fused to the lower lip (labium).
Crustaceans
have a pair of mandibles that typically consist of an enlarged basal segment (coxa) and a
palp (sensory feeler) consisting of all other segments. In some groups, such as the
Branchiopoda, the palp is reduced or absent. Crustacean mandibles may be equipped with special teeth (molar and incisor processes).
See also
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