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 diuretic hormones Insect diuretic hormones Insect diuretic hormones are hormones that regulate water balance through diuretic action. The insect excretory system, responsible for regulating water balance in the insect, comprises the Malpighian tubules and the hindgut (the ileum and rectum). Malpighian tubules secrete primary urine, most of which is passed into the hindgut where water, ions and essential metabolites are reabsorbed before the fluid is excreted. Excretion is under the control of diuretic and anti-diuretic factors, or hormones, comprehensively reviewed by Coast et al. (2002). These factors are produced in neurosecretory cells in the insect nervous system, and stored and released from