Vol 96, No 9 (2016)

In singing insects, the song is an important component of the specific mate recognition system (SMRS). In communities of sympatric singing species, there is a partitioning of communication channels, the so-called “acoustic niches.” Within one community, the songs of different species always differ in temporal or frequency characters, i.e. occupy different acoustic niches. However, conspecific songs do not always act as an interspecific reproductive barrier, despite always being a SMRS component. The species that do not communicate acoustically due to allopatry, different timing of vocalization, inhabiting different biotopes, or unmatched food specializations can produce similar songs while forming reproductively isolated communities. Individuals of different sexes need not only to recognize a conspecific mate but also to evaluate its “quality.” The close-range signal (courtship song) provides more opportunities for choosing the “best” male than does the distant signal (calling song). In many species of Orthoptera, courtship includes not only acoustic but also vibrational, visual, chemical, and mechanical signals. An analysis of cricket songs showed the courtship songs to be on average more elaborate and variable than the calling songs. At the same time, due to the difference in mating behavior between the two groups, the acoustic component of courtship is used for mate quality evaluation to a greater extent in grasshoppers than in crickets. The courtship songs of grasshoppers are generally more elaborate in temporal structure than cricket songs; moreover, they may be accompanied by visual displays such as movements of various body parts. Thus, song evolution in grasshoppers is more strongly driven by sexual selection than that in crickets. According to the reinforcement hypothesis, the premating barrier between hybridizing species becomes stronger in response to reduced hybrid fitness. However, our behavioral experiments with two groups of hybridizing grasshopper species did not confirm the reinforcement hypothesis. We explain this, firstly, by a low level of genetic incompatibility between the hybridizing species and secondly, by high hybrid fitness when attracting a mate. A high competitive capability of hybrids may be accounted for by attractiveness of new elements in hybrid courtship songs. When we divide similar forms based on their songs, we in fact distinguish biological species using the criterion of their reproductive isolation. Acoustic differences between species are usually greater than morphological ones. Therefore, song analysis allows one to determine the real status of doubtful species-rank taxa, to distinguish species in a medley of sibling forms, and to reveal cryptic species in the cases when morphological studies fail to provide a univocal result. At the same time, songs are subject to intraspecific variation the range of which is different in different groups. Therefore, it is necessary to study which degree of difference corresponds to the species level before interpreting the status of some forms based on song comparisons. Besides, song similarities cannot indicate conspecificity of acoustically isolated forms; on the other hand, song differences between these forms prove that they are full-rank species.

Sclerites and musculature of the male genitalia of Nothybidae (Diptera) were studied for the first time. Symmetry of the genital and pregenital sclerites, similar to that in Psilidae, was revealed. The muscles of the male genitalia of Nothybus resemble the apomorphic plan of Cyclorrhapha (Sciomyzidae, Scathophagidae and Calliphoridae) due to the splitting of the hypandrium and hypandrial muscles.

A new genus and a new species, Apocathema lukashevitshae (family Kinnaridae) from Central Chile (the La Campana National Park, Valparaiso Region) belonging to the tribe Prosotropini which was known earlier only from Central America (Panama and the Antilles) is described. The species was collected from the bamboo Chusquea sp.

Two new genera and two new species of the family Issidae are described from Cameroon and the Republic of the Congo; two new species of the genus Issus Fabricius are also described from Libya (the Barka Peninsula) and Morocco; a new species of the genus Kovacsiana Synave is described from northeastern Nigeria. Supplemented descriptions of Chimetopon camerunensis Schmidt, 1910, Hemisobium hammersteini Schmidt, 1911, and Kovacsiana abyssinica Synave, 1956 are provided based on examination of the type specimens. A new subtribe is erected in the tribe Issini for accommodation of the genera Chimetopon Schmidt, 1910, Cascaruna gen. n., and Ikonza Hesse, 1925. Hysteropterum horvathi Melichar, 1906 and H. vibex Melichar, 1906 are transferred to the genus Kovacsiana. Issus acuminatus Lethierry, 1876 is placed in synonymy to I. patruelis Stål, 1861 and transferred to the genus Semissus Melichar, 1906. The faunal species-richness and pattern of the distribution of the family Issidae in Africa are briefly discussed.

A total of 64 species belonging to 10 genera of the subfamily Trioxinae (Hymenoptera, Aphidiidae) are recorded from the former USSR: Betuloxys Mackauer, 1960 (6), Binodoxys Mackauer, 1960 (11), Calaphidius Mackauer, 1961 (1), Falciconus Mackauer, 1959 (2), Harkeria Cameron, 1900 (1), Lipolexis, Förster, 1862 (1), Monoctonia Starý, 1962 (2), Monoctonus Haliday,1833 (6), Sergeyoxys Davidian, 2016 (1), and Trioxys Haliday, 1833 (33). Four species, Harkeria angustivalva (Starý, 1959), Monoctonia japonica Rakhshani et Tomanovic, 2015, Monoctonus mali van Achterberg, 1989, and Trioxys iziphia Mackauer, 1967 are recorded from Russia for the first time. The distribution of 20 species already known from Russia is clarified.