antennal

Antennal is an adjective meaning relating to antennae, the paired sensory appendages on the heads of many arthropods, especially insects and crustaceans. In anatomical and taxonomic usage, antennal describes structures, glands, or functions associated with the antennae, as well as processes such as antennal development or antennal innervation.

Insects commonly have a single pair of antennae, composed of segments that may include a scape, a pedicel, and a multi-segmented flagellum. Antennal morphology is highly diverse and forms the basis for many species' sensory adaptations. Common shape types include filiform (thread-like), moniliform (bead-like), clavate (club-shaped), pectinate (comb-like), and plumose (feathery). Antennal sensilla, small sensory receptors scattered across the surface, enable olfaction, mechanoreception, humidity detection, temperature sensing, and sometimes gustation. The antennal lobes in the insect brain receive input from these sensors and are central to processing olfactory information.

In crustaceans, the term also covers the paired appendages on the head, typically including the antenna (second large pair) and the antennule (the first, often smaller pair). These structures play key roles in chemical sensing, proprioception, and in some species balance or navigation. Antennal function and morphology reflect ecological needs, such as host detection, mate finding, or environmental exploration.

Beyond insects and crustaceans, some arthropod groups show reduced or absent antennae, while others possess highly specialized antennal clubs, tufted sensilla, or geniculate (elbowed) forms. The study of antennal morphology and function informs understanding of sensory ecology, behavior, and neural processing.