The leafhopper Macrosteles laevis, like other plant sap-feeding hemipterans, lives in obligate symbiotic association with microorganisms. The symbionts are harbored in the cytoplasm of large cells termed bacteriocytes, which are integrated into huge organs termed bacteriomes. Morphological and molecular investigations have revealed that in the bacteriomes of M. laevis, two types of bacteriocytes are present which are as follows: bacteriocytes with bacterium Sulcia and bacteriocytes with Nasuia symbiont. We observed that in bacteriocytes with Sulcia, some cells of this bacterium contain numerous cells of the bacterium Arsenophonus. All types of symbionts are transmitted transovarially between generations. In the mature female, the bacteria Nasuia, bacteria Sulcia, and Sulcia with Arsenophonus inside are released from the bacteriocytes and start to assemble around the terminal oocytes. Next, the bacteria enter the cytoplasm of follicular cells surrounding the posterior pole of the oocyte. After passing through the follicular cells, the symbionts enter the space between the oocyte and follicular epithelium, forming a characteristic “symbiont ball.”

The symbiotic systems (types of symbionts, their distribution in the host insect body, and their transovarial transmission between generations) of four Deltocephalinae leafhoppers: Fieberiella septentrionalis, Graphocraerus ventralis, Orientus ishidae, and Cicadula quadrinotata have been examined by means of histological, ultrastructural, and molecular techniques. In all four species, two types of symbionts are present: bacterium Sulcia (phylum Bacteroidetes) and yeast-like symbionts closely related to the entomopathogenic fungi (phylum Ascomycota, class Sordariomycetes). Sulcia bacteria are always harbored in giant bacteriocytes, which are grouped into large organs termed Bbacteriomes.^In F. septentrionalis, G. ventralis, and O. ishidae, numerous yeast-like microorganisms are localized in cells of the fat body, whereas in C. quadrinotata, they occupy the cells of midgut epithelium in large number. Additionally, in C. quadrinotata, a small amount of yeast-like microorganisms occurs intracellularly in the fat body cells and, extracellularly, in the hemolymph. Sulcia bacteria in F. septentrionalis, G. ventralis, O. ishidae, and C. quadrinotata, and the yeastlike symbionts residing in the fat body of F. septentrionalis, G. ventralis, and O. ishidae are transovarially transmitted; i.e., they infect the ovarioles which constitute the ovaries.

ABSTRACT. The ovaries of the leafhopper Deltocephalus pulicaris are accompanied by large organs termed bacteriomes, which are composed of numerous polyploid cells called bacteriocytes. The cytoplasm of bacteriocytes is tightly packed with symbiotic microorganisms. Ultrastructural and molecular analyses have revealed that bacteriocytes of D. pulicaris contain two types of symbionts: the bacterium "Candidatus Sulcia muelleri" and the bacterium "Candidatus Nasuia deltocephalinicola". Both symbionts are transovarially transmitted from the mother to the next generation.

New data on the distribution, biology, and ecology of the longhorn beetles occurring in Mongolia are presented together with a list of 35 species that were collected during a one-month entomological expedition in August 2015. New localities of some rare taxa endemic to Mongolia, such as Eodorcadion dorcas dorcas (Jakovlev, 1901), E. humerale impluviatum (Faldermann, 1833), and E. intermedium intermedium (Jakovlev, 1889) are given. High-quality photographs of several rather unique species, i.e., Pachytodes longipes (Gebler, 1832), Eodorcadion maurum australe Danilevsky, 2014, E. oryx (Jakovlev, 1895), Monochamus impluviatus impluviatus (Motschulsky, 1859), and M. sutor longulus (Pic, 1898) along with images of their habitats or feeding grounds are also presented. Furthermore, the ecological role of the fireweed Chamaenerion angustifolium (L.) Scop. in the case of boreal anthophilous cerambycid species is highlighted for the first time.

Th is study provides the fi rst data on the occurrence of the mosaic leafh opper Orientus ishidae (Matsumura, 1902) (Hemiptera: Cicadellidae) in Poland. Th is species is native to Southeast Asia, adventive in Europe and feeds on cultivated plants. Orientus ishidae is a well-known carrier of Grapevine fl avescence doree phytoplasma which causes the grapevine yellows disease. Symptoms of phytoplasma diseases of grapevine include deformations, leaf chlorosis and withering of plants. Th e appearance of this species in Poland might be caused by observed climate variations and insuffi cient plant health controls in the international trade of plants.