In insect anatomy the arista is a simple or variously modified
apical or subapical bristle, arising from the third
antennal
Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for sensing in arthropods.
Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one o ...
segment. It is the
evolutionary remains of antennal segments, and may sometimes show signs of segmentation. These segments are called aristameres.
The arista may be bare and thin, sometime appearing no more than a simple bristle;
pubescent, covered in short hairs; or
plumose, covered in long hairs.
The presence of an arista is a feature of the
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 advanced ...
(flies)
suborder
Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...
Brachycera and may be especially well-developed in some species. It is also present in some members of
Hemiptera
Hemiptera (; ) is an order (biology), order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, Reduviidae, assassin bugs, Cimex, bed bugs, and shield bugs. ...
(true bugs), specifically in the suborder
Auchenorrhyncha. The arista is often covered in multiple kinds of
sensilla
A sensillum (plural ''sensilla'') is an arthropod sensory organ protruding from the cuticle of exoskeleton, or sometimes lying within or beneath it. Sensilla appear as small hairs or pegs over an individual's body. Inside each sensillum there are ...
, or sense organs, such as chemo, hygro, and thermoreceptors, which allow the insects to detect changes in their environment.
References
Insect anatomy
Brachycera
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Auchenorrhyncha