The chromosome complements of thirteen species of the planthopper family Dictyopharidae are described and illustrated. For each species, the structure of testes and, on occasion, ovaries is additionally outlined in terms of the number of seminal follicles and ovarioles. The data presented cover the tribes Nersiini, Scoloptini and Dictyopharini of the subfamily Dictyopharinae and the tribes Ranissini, Almanini, and Orgeriini of the Orgeriinae. The data on the tribes Nersiini and Orgeriini are provided for the first time. Males of Hyalodictyon taurinum and Trimedia cf. viridata (Nersiini) have 2n = 26 + X; Scolops viridis, S. sulcipes, and S. abnormis (Scoloptini) 2n = 36 + X; Callodictya krueperi (Dictyopharini) 2n = 26 + X; Ranissus edirneus and Schizorgerius scytha (Ranissini) 2n = 26 + X. Males of Almana longipes and Bursinia cf. genei (Almanini) have 2n = 26 + X and 2n = 24 + XY, respectively. The latter chromosome complement was not recorded previously for the tribe Almanini. Males of Orgerius ventosus and Deserta cf. bipunctata (Orgeriini) have 2n = 26 + X. The testes of males of A. longipes and B. cf. genei each have 4 seminal follicles, which is characteristic of the tribe Almanini. Males of all other species have 6 follicles per testis. When the ovaries of a species were also studied, the number of ovarioles was coincident with that of seminal follicles. For comparison, Capocles podlipaevi (2n = 24 + X and 6 follicles per testis in males) from the Fulgoridae, the sister family to Dictyopharidae, was also studied. We supplemented all the data obtained with our earlier observations on Dictyopharidae. The chromosomal complement of 2n = 28 + X or that of 2n = 26 + X and 6 follicles per testis are suggested to be the ancestral condition among Dictyopharidae, from which taxa with various chromosome numbers and testes each with 4 follicles have differentiated.
A particular case of the alteration of the organization of a developmental module is presented, viz. mixed gynandromorphism in Creobroter gemmatus, in which a male exhibits the usual fore- and hind wing venation and shape of its sex, but patterns of coloration typical of females. Homologies between corresponding areas of the fore- and hind wings are suggested. "Feminization" is defined as the occurrence of traits typical of the female phenotype in a male, and is suggested as a plausible way in which insect wing morphology may be transformed.
The species of the Poecilimon heroicus-group occur around the Caucasus (from north-eastern Turkey to south-eastern Ukraine). We describe the diagnostic morphological characters of all these species and the male calling song of three of the four species. Based on this data the following phylogenetic relationship is derived (P. tschorochensis (P. tricuspis (P. heroicus, P. bifenestratus))). Within the genus Poecilimon, the species can be recognised by a relatively wide pronotum and large tegmina. In one species, Poecilimon tschorochensis Adelung, 1907 (type species of the monotypic genus Artvinia Karabag, 1962, syn. n.; P. rammei Miram, 1938, syn. n.), the tegmina are very large and the song has unusually low spectral components. This species produced di-syllabic echemes at intervals of about 10 s. In two other species of the group, P. heroicus and P. bifenestratus, the calling song of males consists of an uninterrupted dense sequence of long syllables (syllable duration around 0.5 s; ca. 1 syllable/s at 20°C). In these species the auditory spiracles are reduced in size in both sexes, and the females have extremely small tegmina and are unable to respond to the male song acoustically, which would be typical for Phaneropteridae. The change in communication from acoustically responding to mute females has not been previously documented within a group of closely related species.
Two principal pheromones are essential in all cockroach sexual behavioral sequences: the volatile sex attractant pheromone released by one partner for long distance attraction and an aphrodisiac sex pheromone produced exclusively by male tergal glands for female mounting and feeding behavior. In the Blaberinae subfamily, the female produces volatile sex attractant pheromones and the male, aphrodisiacs. A close relationship is known to exist between the release of these pheromonal signals from specific glands and the corresponding behaviors (female calling posture and male wing raising). However, in this cockroach group, no data on the glands secreting sex attractant pheromones and aphrodisiacs have been available until now. In seven species of the Blaberinae subfamily: Blaberus colosseus, B. craniifer, B. discoidalis, Blaptica interior, Byrsotria fumigata, Eublaberus distanti and E. posticus; one species of the Zetoborinae subfamily: Schultesia lampyridiformis; one species of the Epilamprinae subfamily: Epilampra maya and one species of the Panesthiinae subfamily, Panesthia sp., the females possess all pygidial glands on the 10 th tergite and the males have tergal glands situated anteriorly, generally on tergites T1 and T2. These glands are formed of type 3 glandular units with two cells, i.e. glandular and canal cells. The uniform presence of female pygidial glands and male tergal glands explains their relationship with their corresponding sexual behaviors.
The karyotypes of one mud loach and three spined loach species occurring in the Far East region of Russia are presented. Misgurnus nikolskyi has 2n=50 with NF=64, Cobitis lutheri has 2n=50 and NF=70, C. choii has 2n=50 and NF=68, and C. melanoleuca has 2n=50 and NF=72. The karyotype of M. mohoity is proved to consist of 50 chromosomes. These results are discussed in relation with some taxonomic and evolution problems in loaches
While the ultimate causes and adaptive significance of sexual size dimorphism (SSD) have been extensively studied, the developmental mechanisms behind this phenomenon have received little attention. Going through an additional larval instar may form a specific way of achieving SSD in arthropods. In the present study, the mechanisms of SSD determination of two lymantriid moths, with marked SSD, were studied. In both species, females tended to go through an additional instar compared to males, and form pupae that were more than twice the weight of the males. To reveal the role of an extra instar, larval growth was monitored in the laboratory and the growth parameters were analysed as dependent on sex and developmental type (number of instars). Prolongation of growth by means of adding an additional larval instar in females turned out to be the key mechanism in the determination of the highly female-biased SSD in the species studied. There is thus a developmental mechanism available that permits achieving a larger size by means of extending the growth period. This provides evidence against constraint-based evolutionary explanations for body sizes in insects. There was no considerable accumulation of SSD during earlier larval life when females went through more instars than males. In contrast, in those cases in which males and females had the same number of instars, SSD accumulated gradually during the course of several larval instars. Longer growing period turned out to be a crucial mechanism leading to the female-biased SSD even when instar number did not differ between sexes, although higher instantaneous relative growth rates of females also played a complementary role in the latter case. Within sexes, an additional instar was characteristic of initially smaller larvae, as predicted by the "threshold size" hypothesis.
The maximum size of ingested ball-shaped particles was determined in three species of adult dung feeding beetle: Anoplotrupes (Geotrupes) stercorosus and Geotrupes spiniger (Geotrupidae, Geotrupinae) and Sphaeridium lunatum (Hydrophilidae, Sphaeridiinae). Maximum diameters were 40-65 µm, 60-75 µm and 16-19 µm in A. stercorosus, G. spiniger and S. lunatum, respectively, and it was concluded that these beetles feed in the same way as found in previous studies on coprophagous scarabaeids (Scarabaeinae and Aphodiinae). Coarse particles, mainly indigestible plant fragments, are rejected by an unknown filtering mechanism, and only very small particles are actually ingested. The two geotrupids, however, tolerate somewhat larger particles than do scarabaeines of similar size. This may reflect a lower degree of specialisation towards dung feeding in the geotrupids than in the scarabaeines. In several ways, the mouthparts of the coprophagous Scarabaeidae, Geotrupidae and Hydrophilidae show essentially the same morphological modifications that must be adaptations for dung feeding. For the hydrophilid (Sphaeridium), such modifications are described for the first time. They include asymmetric mandibular molars (right convex, left concave), fitting exactly into each other, with highly specialised surfaces that may concentrate the food prior to ingestion by squeezing fluid out of it. Other examples are the conjunctives (scarabaeids and geotrupids) or similar structures (the hydrophilid) and the large, hairy, pad-like distal lobes of the maxillar galeae. Provided that current views on the evolutionary history of these beetles are correct, dung feeding has arisen independently in the Scarabaeidae, Geotrupidae and Hydrophilidae. If so, the feeding on very small particles and the concomitant modifications of mouthparts in these three groups must be results of parallel evolution.
The suctorial proboscis of adult Lepidoptera represents a key morphological innovation that enabled these insects to gain access to new food sources. In the ancestral condition of the lepidopteran proboscis only extrinsic galeal muscles are present in the basal joint region. The presence of additional muscles (i.e., the intrinsic galeal muscles) is regarded as a morphological novelty of the Myoglossata that evolved after the galeae were modified to form suctorial mouthparts. The present comparative investigation of the galeal anatomy in representatives of all major taxa revealed that the intrinsic galeal muscles are derived from the basal galeal musculature. In the examined Neopseustoidea, Exoporia, Nepticuloidea, Incurvarioidea, and Tischerioidea all galeal muscles have their origin in the stipes-galea joint and/or in the proximal region of the galea. Two muscle units form the basal galeal musculature of the joint region and one to three longitudinal muscles extend into the galea lumen. Multiple intrinsic galeal muscles, of which both the origin and attachment sites are markedly distal from the basal joint region are regarded as a groundplan autapomorphy of the Ditrysia. Some slightly oblique muscles may occur along the lateral wall; these were lost in species with extremely slender galeae. In most investigated Obtectomera two series of intrinsic galeal muscles occur; these are the (1) oblique lateral intrinsic galeal muscles, which are arranged one upon the other along the lateral proboscis wall and (2) the median intrinsic galeal muscles, which run more or less longitudinally along the ventral wall. Oblique muscle arrangement probably evolved in concert with the functional demands of a long lepidopteran proboscis. A likely evolutionary pathway to account for the serial arrangement of galeal muscles is proposed.
The distribution patterns of the X0/XX and neo-XY/neo-XX chromosome races, subraces, and "hybrids" between subraces of the grasshopper P. sapporensis were analyzed. The origin of the observed variation is Robertsonian translocations between a sex chromosome and an autosome, and chromosome rearrangements. The fixation levels of inversions varied depending on geographic regions. No hybrid population is known implying that a strong reproductive isolation system exists in hybrids between the different chromosomal races. The probable reasons for the purity of X0 and neo-XY chromosome races and high chromosome polymorphism in contact zones between chromosomal subraces are discussed. The presence of isolating barriers between chromosome races indicates a review of the taxonomic structure of P. sapporensis is required. It is proposed to divide P. sapporensis into two sibling species, which differ in the chromosome mechanisms of the sex determination system.The analysis of the distribution of chromosomal races and subraces of P. sapporensis allows a reconstruction of the history of this species in the Okhotsk sea region.