Petiole (insect anatomy) a pedicel, but in entomology, that term is more correctly reserved for the second segment of the antenna; while in arachnology, 'pedicel' is the accepted term to define the constriction between the cephalothorax and abdomen of spiders. The plump portion of the abdomen posterior to the petiole (and postpetiole in the Myrmicinae) is called the gaster. The structure of the petiole is an easy way to visually classify ants, because the major subfamilies of Formicidae have structural differences: some ants have two-segmented petioles, while others have a single-segmented petiole. Petiole may also be used in the context of wing veins,
Insect olfaction study has demonstrated the olfactory role of ovipositor in fig wasps. Inside of these olfactory organs there are neurons called olfactory receptor neurons which, as the name implies, house receptors for scent molecules in their cell membrane.The majority of olfactory receptor neurons typically reside in the antenna. These neurons can be very abundant, for example Drosophila flies have 2,600 olfactory sensory neurons. Insects are capable of smelling and differentiating between thousands of volatile compounds both sensitively and selectively. Sensitively is how attune the insect is to very small amounts of an odorant or small changes in the concentration of an