Буынақты бунақденелердің сезім мүшелері – антенналар

Paired appendages used for sensing in arthropods

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 or more jointed segments. While they are typically sensory organs, the exact nature of what they sense and how they sense it is not the same in all groups. Functions may variously include sensing touch, air motion, heat, vibration (sound), and especially smell or taste. Antennae are sometimes modified for other purposes, such as mating, brooding, swimming, and even anchoring the arthropod to a substrate. Except for the chelicerates and proturans, which have none, all non crustacean arthropods have a single pair of antennae.

Some claim insects evolved from prehistoric crustaceans, and they have secondary antennae like crustaceans, but not primary antennae. Antennae are the primary olfactory sensors of insects and are accordingly well equipped with a wide variety of sensilla (singular: sensillum). Paired, mobile, and segmented, they are located between the eyes on the forehead. Embryologically, they represent the appendages of the second head segment. 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 do not. Antennal fibrillae play an important role in Culex pipiens mating practices. The erection of these fibrillae is considered to be the first stage in reproduction. These fibrillae serve different functions across the sexes. As antennal fibrillae are used by female C. pipiens to locate hosts to feed on, male C. pipiens utilize them to locate female mates.

The three basic segments of the typical insect antenna are the scape or scapus (base), the pedicel or pedicellus (stem), and finally the flagellum, which often comprises many units known as flagellomeres. The pedicel (the second segment) contains the Johnston's organ which is a collection of sensory cells. The scape is mounted in a socket in a more or less ring shaped sclerotised region called the torulus, often a raised portion of the insect's head capsule. The socket is closed off by the membrane into which the base of the scape is set. However, the antenna does not hang free on the membrane, but pivots on a rigidly sprung projection from the rim of the torulus. That projection on which the antenna pivots is called the antennifer. The whole structure enables the insect to move the antenna as a whole by applying internal muscles connected to the scape. The pedicel is flexibly connected to the distal end of the scape and its movements in turn can be controlled by muscular connections between the scape and pedicel. The number of flagellomeres can vary greatly between insect species, and often is of diagnostic importance. True flagellomeres are connected by membranous linkage that permits movement, though the flagellum of "true" insects does not have any intrinsic muscles. Some other Arthropoda do however have intrinsic muscles throughout the flagellum. Such groups include the Symphyla, Collembola and Diplura. In many true insects, especially the more primitive groups such as Thysanura and Blattodea, the flagellum partly or entirely consists of a flexibly connected string of small ring shaped annuli. The annuli are not true flagellomeres, and in a given insect species the number of annuli generally is not as consistent as the number of flagellomeres in most species. In the groups with more uniform antennae (for example: millipedes), all segments are called antennomeres. Some groups have a simple or variously modified apical or subapical bristle called an arista (this may be especially well developed in various Diptera).

Olfactory receptors on the antennae bind to free floating molecules, such as water vapour, and odours including pheromones. The neurons that possess these receptors signal this binding by sending action potentials down their axons to the antennal lobe in the brain. From there, neurons in the antennal lobes connect to mushroom bodies that identify the odour. The sum of the electrical potentials of the antennae to a given odour can be measured using an electroantennogram. In the monarch butterfly, antennae are necessary for proper time compensated solar compass orientation during migration. Antennal clocks exist in monarchs, and they are likely to provide the primary timing mechanism for sun compass orientation. In the African cotton leafworm, antennae have an important function in signaling courtship. Specifically, antennae are required for males to answer the female mating call. Although females do not require antennae for mating, a mating that resulted from a female without antennae was abnormal. In the diamondback moth, antennae serve to gather information about a host plant's taste and odor. After the desired taste and odor has been identified, the female moth will deposit her eggs onto the plant. Giant swallowtail butterflies also rely on antenna sensitivity to volatile compounds to identify host plants. It was found that females are actually more responsive with their antenna sensing, most likely because they are responsible for oviposition on the correct plant. In the crepuscular hawk moth (Manduca sexta), antennae aid in flight stabilization. Similar to halteres in Dipteran insects, the antennae transmit coriolis forces through the Johnston's organ that can then be used for corrective behavior. A series of low light, flight stability studies in which moths with flagellae amputated near the pedicel showed significantly decreased flight stability over those with intact antennae. To determine whether there may be other antennal sensory inputs, a second group of moths had their antennae amputated and then re attached, before being tested in the same stability study. These moths showed slightly decreased performance from intact moths, indicating there are possibly other sensory inputs used in flight stabilization. Re amputation of the antennae caused a drastic decrease in flight stability to match that of the first amputated group.