The Ultrastructure Of The Olfactory Sensillum And The Antennal Lobe Of Holotrichia Diomphalia Bates

Holotrichia diomphalia Bates is the dominant species of the underground pest in northeast area.The ultrastructure of olfactory sensillum on antennae of Holotrichia diomphalia Bates adult was studied by using SEM and TEM.The technology of the paraffin section and the genera method for silvering invertebrate nervous systems had been used for the research of the ultrastructure of the antennal lobe within deutocerebrum.These results generally show the number,shape,size and position of glomeruli.The glomerular nomenclature used in the present study is based on the general position of single glomeruli in the AL.According to continuous sections we present a three-dimensional reconstruction of the golmerular of the AL of the Holotrichia diomphalia Bates.These results offer the basic dates for the research of the olfaction physiology and the mechanism of the scarabaeus.The conclusions as follows:The results showed that the olfactory sensillum concentrated on antennal lamellae and all those sensillums were located on the sunken cavity formed by the antennal cuticle depressions. Two types of olfactory sensillum on lamellae,the sensilla basiconca(S.ba) and sensilla placodea(S.pl) were found.Four types of S.ba and five types of S.pl were distinguished according to the difference shape of cone and plate.The length of each lamella on antenna in male is longer than in female,and the total numbers of sensilla were far more than in female. The number of S.pl has showed not obvious the difference between the both sexes,but the number of S.ba in males was about nine times more than in females.The result would be suggested that the S.ba was the sensillum take for reception of pheromone and S.pl was used for reception of plant odors.A spot of the sensilla coeloconica on antennal lamellae and the sensilla campaniformia on the ege of the antennal lamellae as well as the sense hair on the Scapus,Pedicellus and Flagellum may be the physical olfaction.TEM showed the internal structure of the sensilla basiconca and the sensilla placodea accord with the character of the olfactory sensillum.Both of sensillum showed single-walled, with a plenty of pores and pore tubules on the surface of the sensillum.The pore is the channel which the odor come from the outsider world penetrated from cuticle to coelom. Besides the diameter of the pore was about 20-40nm.The numbers of olfactory receptor neuron (ORN) inside sensillum were not consistency with one ORN,two ORNs and three ORNs.In Holotrichia diomphalia Bates,the ALs protruded on either side of the forepart of the deutocerebrum.The axons of the olfactoreceptor ORNs most from antenna and some from maxillary palp link up of the same side of AL.Close comparison of the glomeruli organization of the AL of both male and female Holotrichia diomphalia Bates revealed sexual dimorphism. Overall,we were able to identify 62 and 59 glomeruli in female and male Holotrichia diomphalia Bates respectively based on silvering invertebrate nervous.Besides the little difference in number,the sexual dimorphism has been showed in size both female and male AL, in addition the sexual dimorphism also showed individual glomeruli in position and size.In male,the MGC(macroglomerular complex) has been observed,part of glomerulis were most difficult to compartmentalize because of their blurry outline than female.