Ultrastructure of scent glands in larvae of Apateticus bracteatus (Hemiptera: Pentatomidae) and chemical composition of the secretion

Abstract

The three dorsal abdominal glands in larvae of Apateticus bracteatus (Pentatomidae) secrete a mixture of compounds. Major volatile constituents of the secretion are identified, herein, as tridecane and 2-octenal. There are also trace amounts of 2-hexenal and two other unidentified compounds.Each of the glands has paired orifices that are located between tergites 3/4, 4/5, and 5/6, but only the most anterior gland is paired. In anterior glands of midinstar larvae, glandular cells associated with ducts, and interstitial glandular cells are distributed along the ventral walls of the reservoirs. In posterior glands, columnar glandular cells are located in the anterior dorsal wall of the reservoirs; secretory cells associated with ducts, and nonglandular interstitial cells are distributed throughout the ventral and posterior walls of the reservoirs. The interstitial glandular cells of the anterior gland and the columnar glandular cells of the middle and posterior glands contain cytoplasmic organelles characteristic of lipid-producing cells. In all glands the secretory cells associated with ducts secrete lipids. Evidence indicating the importance of Golgi and ER in secretion synthesis is presented. The reservoirs and ducts have a thin cuticular lining.The bearing of the results on present ideas of gland function in Heteroptera is discussed.