Insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...

are among the most diverse groups of

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

s on the planet, including more than a million described

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

and representing more than half of all known living organisms. The number of

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

species is estimated at between six and ten million, found in nearly all

environments Environment most often refers to: __NOTOC__ * Natural environment, referring respectively to all living and non-living things occurring naturally and the physical and biological factors along with their chemical interactions that affect an organism ...

, although only a small number of species occur in the oceans. This large extant means that the dietary habits of taxa include a large variety of behaviors.

Insect mouthparts

The insect mouthparts consist of the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

, labium, and in some species the

mandibles In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

. The labrum is a simple fused

sclerite A sclerite (Greek language, Greek , ', meaning "hardness, hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instea ...

, often called the upper lip, and moves longitudinally, which is hinged to the clypeus. The mandibles (jaws) are a highly

sclerotized Sclerosis (also sclerosus in the Latin names of a few disorders) is a hardening of tissue and other anatomical features. It may refer to: * Sclerosis (medicine), a hardening of tissue * in zoology, a process which forms sclerites, a hardened exo ...

pair of structures that move at right angles to the body; used for biting, chewing and severing food. The maxillae are paired structures that can also move at right angles to the body and possess segmented palps. The labium (lower lip) is the fused structure that moves longitudinally and possesses a pair of segmented

palp Pedipalps (commonly shortened to palps or palpi) are the secondary pair of forward appendages among chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicera ...

s. The mouthparts, along with the rest of the head, can be articulated in at least three different positions: prognathous,

opisthognathous This glossary of entomology describes terms used in the formal study of insect species by entomologists. A–C A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though ...

and hypognathous. In species with prognathous articulation, the head is positioned vertically aligned with the body, such as species of Formicidae; while in a hypognathous type, the head is aligned horizontally adjacent to the body. In an opisthognathous head, it was positioned diagonally, such as species of

Blattodea Blattodea is an order (biology), order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but genetics, genetic and molecular evidence suggests they evolved from within the cockroach ...

and some

Coleoptera Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

ns. The mouthparts vary greatly among insects of different orders but there are two main functional groups: mandibulate and haustellate. Haustellate mouthparts are those used for sucking liquids and can be further classified, by the presence of stylets, which include: piercing-sucking, sponging, and siphoning. The stylets are needle-like projections used to penetrate plant and animal tissue. The stylets and the feeding tube form the modified mandibles, maxilla, and hypopharynx. *Mandibulate: These forms of mouthparts are among the most common in insects, which are used for biting and grinding solid foods. *Piercing-sucking: These forms of mouthparts have stylets, and are used to penetrate solid tissue and then suck up liquid food. *Sponging: These forms of mouthparts are used to sponge and suck liquids and lack stylets (e.g. most

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...

). *Siphoning: These forms of mouthparts lack stylets and are used to suck liquids, which are commonly found among species of

Lepidoptera Lepidoptera ( ) or lepidopterans is an order (biology), order of winged insects which includes butterflies and moths. About 180,000 species of the Lepidoptera have been described, representing 10% of the total described species of living organ ...

. Mouthparts that are mandibular are found in species of

Odonata Odonata is an order of predatory flying insects that includes the dragonflies and damselflies (as well as the '' Epiophlebia'' damsel-dragonflies). The two major groups are distinguished with dragonflies (Anisoptera) usually being bulkier with ...

, adult

Neuroptera The insect order (biology), order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order consists of some 6,000 species. Neuroptera is grouped together with the Megaloptera (alderflies, f ...

Hymenoptera Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typi ...

Orthoptera Orthoptera () is an order of insects that comprises the grasshoppers, locusts, and crickets, including closely related insects, such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – gras ...

, and

. However most adult Lepidoptera have siphoning mouthparts, while the larvae (commonly called

caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...

s) are the ones with the mandibles.

Measurement

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly" ...

'' has a long history of use as a model organism for genetic studies. However, the quantitative analysis of feeding behavior remains "challenging" and it is "often ignored or poorly characterized". Among many methods, the most commonly applied are capillary feeder (CAFE), radioactive tracer labeling in food, dye tracer labeling in food and counting of proboscis extension (PE) events.

References

{{reflist Eating behaviors

Insect mouthparts

Measurement

See also

References