Structure and Function of Olfactory Sensilla on the Antennae of Soybean Aphids, Aphis glycines - Du, Yongjun; Yan, Fushun; Tang, Jue (My University, 2017)
Observation were made on the morphology of antennal sensilla of Aphis glycines using scanning electron microscopy. Apterae have antennal sensilla similar to those of the alatae, A group of four stout and often blunt-ended hairs appear at the tip of the antenna. A flattened sense organ (primary rhinarium) is located on the fifth antennal segment and that on the sixth segment there are four sensilla coeloconica and two sensilla placodea. They are ringed with a fringe of cuticle of which the finger-like extensions might function as a protective sieve against the entry of undesirable particles. Secondary rhinaria consist of sensilla placoidea resembling that on the fifth antennal segment, but without the elaborate fringe. Alatae differ even more markedly from apterae by possession of several to many secondary rhinaria on the flagellum. There were many secondary rhinaria on the third and the fourth, even the fifth segment in male A. glycines. The olfactory site of tested chemicals were analyzed by making use of EAG technique. It is demonstrated that primary rhinarium on the sixth antennal segment in slate Virginoparae responds to terpene derivatives (their alcohols, aldehydes and esters), but not to terpene hydrocarbons. While the rhinarium on the fifth segment responds to terpene hydrocarbons and not to terpene derivatives. Green leaf volatile and aromatic compounds were perceived by primary rhinaria on both segments, but the intensities of olfactory respones to the chemicals in each rhinarium are different. Besides the primary rhinaria on the two segments, receptor cells which responded strongly to (E)-2-hexanal and 1-hexanal were found on other sensilla, which might be the trichodea (1 µm) and the small placodea (0.8 µm) on the fifth segment. However, there was no direct electrophysiological evidence for it. Primary rhinarium on the sixth segment consists of main olfactory receptors for 3-octen-1-ol; moreover, trichodeum and small placodeum on the some segment might also contribute to the sensory response to 3-octen-1-ol. Primary rhinarium on the sixth segment was proved to be the sensory site for (E)-ß -farnesene in alate and apterous virgenoparae. Caryophyllene, which is an inhibitor of alarming pheromone, and (E)-ß-farnesene tarnesene could evoke a weak response in the secondary rhinaria on the t hird segment, and the primary rhinarium in apterous virginoparae.
Originating text in Chinese.
Citation: Du, Yongjun, Yan, Fushun, Tang, Jue. (1995). Structure and Function of Olfactory Sensilla on the Antennae of Soybean Aphids, Aphis glycines. Kun chong xue bao.Acta entomologica Sinica, 38(1), 1-7.