Internal morphology of two species of Lagenochitina (Chitinozoa)

Internal and external structures of Lagenochitina boja Bockelie 1980 and L. esthonica Eisenack 1955 have been examined with a scanning electron microscope. The material derives from limestone samples from the Arenig to ?Lower Llanvirn succession of NE Spitsbergen. The species possesses both an operculum and a prosoma (Bockelie, 1978). The operculum, in the shape of a thin flat disc, closes the aperture of the test. A cylindroconical structure is enclosed in the test aborally of the operculum. the cylindrical part of this structure, the prosoma, is transversed by numerous thin disc-shaped laminae. The sequence of thin laminae is terminated in a thicker lamina, here termed the subex. The prosoma wall is extended aborally forming a conical structure, the rica. The prosomai of individual specimens show variation in length, microstructures and the attachment to the test. The internal structures of Lagenochitina species are compared with similar structures known from other chitinozoan species.     

The embryonic apolyses of Schistocerca gregaria (Orthoptera)

The origin and differentiation of the ecdysial glands and the appearance of the cuticles were studied in embryos of Schistocerca gregaria at corresponding stages. The development of the cuticle was also studied in headless embryos explanted in vitro.     

Effects of supernumerary heterochromatin on chiasma condition in two species of Acrididae (Orthoptera)

Amblytropidia australis and Dichroplus elongatus were found to be polymorphic for supernumerary heterochromatin. In both, basic karyotypes are 2n=22+XO in males.Mitotically unstable extra chromosomes were detected in a population of A. australis. The Bs are telocentric and their number varies from O to 2 within individuals. Mean frequencies of interstitial and total chiasmata at diplotene were compared between individuals with and without Bs. The mean frequency of interstitial chiasmata increases with the number of Bs per cell.A supernumerary terminal segment in S₁₀ pair was observed in a heterozygous condition in several individuals of D. elongatus. The localization and frequency of chiasmata at diplotene were studied. The segment has an intrachromosomal effect since it modifies the location of chiasmata in the bivalent involved.Fellow of the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET).     

Pattern of genetic differentiation in two Isophya species (Orthoptera: Tettigonoidea) in north-east Hungary

Allozyme polymorphism was studied in two populations of Isophya kraussi and Isophya stysi. Both species are flightless and have low dispersal ability. As a consequence, we expected high level of genetic differentiation among their local populations. Samples were collected in three regions of Hungary. Enzyme polymorphism was investigated at 10 loci (Aldox, Est, Got, Gpdh, Hk, Idh, Mdh, Me, Pgi and Pgm) in both species. High levels of polymorphism were detected in all samples. Gpdh proved to be diagnostic as there were no common alleles in the two species. At four further loci (Got, Hk, Mdh and Me), the two species had one common allele together with one or more differentiating alleles. We detected high F _IT values implying a high level of genetic variation. The positive F _IS values suggested a tendency of heterozygote deficiency in both species. The highly significant overall F _ST values indicated clear genetic differentiation among the local populations. Thus our results confirmed the taxonomic status of these two species. The dendrogram constructed on the basis of Nei's genetic distances and the results of the PCA analyses fully confirmed those obtained by F-statistics.     

Acoustic communication and sexual selection in Orthoptera (Insecta)

Comparison of calling and courtship songs and mating strategies in different groups of Orthoptera shows that acoustic signals in bush crickets (Tettigonioidea) are used for searching conspecific mates at a distance, and song evolution is primarily driven by the acoustic surroundings and simultaneously singing other species. The role of sexual selection in the evolution of acoustic signals in bush crickets is much less important than in the evolution of other nonacoustic signals employed during direct contact. Acoustic signals of crickets (Grylloidea) are involved in both distant and short-range communication. Acoustic courtship signals, along with other courtship components, may offer the material for sexual selection, although, essentially, evolution of acoustic signals in crickets is determined by the acoustic surroundings. Acoustic communication in the grasshoppers of the subfamily Gomphocerinae is mainly a short-distance communication. Acoustic signals of Gomphocerinae are highly variable and elaborate in temporal parameters, and therefore can serve for evaluation of the mate "quality". Song evolution in this group is to a greater extent driven by sexual selection than by the acoustic surroundings and, therefore, could proceed faster than in other groups of Orthoptera and play a major role in speciation.     

两种微翅蚱属昆虫雄性的首次报道（直翅目：蚱总科：蚱科）

对微翅蚱属Alulatettix的2种昆虫:安徽微翅蚱A.anhuiensis Zheng,2001和天柱山微翅蚱A.tianzhushanensis Zhang,Deng&Zha,2014的雄性分别进行了首次报道。研究标本存放于淮北师范大学生命科学学院标本室。     

The ultrastructural organization of peripheral nerves in two insect species (Periplaneta americana and Schistocerca gregaria)

The ultrastructural organization of various peripheral nerves, including the crural nerve, has been investigated in the locust and cockroach. In some cases the larger nerves are ensheathed by a fat body layer which is not always complete. However, like many nervous connectives, they do possess a continuous acellular neural lamella and a perineurial cell layer which surround the glial-axonal mass. Adjacent perineurial cells are associated with one another by septate desmosomes, gap junctions and tight junctions. These last may represent the morphological basis of the ‘blood-brain barrier’ observed electrophysiologically in these peripheral nerves in another report. Very small nerves of the cockroach, however, although lying embedded in a neural lamella, do not possess a specialized perineurial layer displaying junctional complexes, unless they contain one or more large axons. If they have only one or more small axons, these small nerves may either appear naked, or display a single glial cell process loosely enveloping them; in either case there is no structural basis for a ‘barrier’ system. Various comparisons have been made between locust crural nerve and the cockroach central nervous connectives in an attempt to correlate some aspects of their ultrastructural organization with relevant electrophysiological information.     

The species of Coleosporium (Pucciniales) on Solidago in North America

Species of Coleosporium (Pucciniales) are rust fungi that typically alternate between pines and angiosperms. In North America, species of Coleosporium often infect Solidago (goldenrods), although their taxonomy on these hosts is unresolved. Joseph. C. Arthur and George B. Cummins regarded these as a single species, Coleosporium solidaginis (fide Arthur) or C. asterum (fide Cummins), but later inoculation studies demonstrated the presence of more than one species, distinguishable by their aecial hosts. A more recent taxonomic study of Coleosporium found that specimens on Solidago identified as C. asterum in North America were not conspecific with the type, which is from Japan, prompting the present study. Herein, we conducted a systematic study on ca. 60 collections of Coleosporium infecting species of Asteraceae from North America using regions of ribosomal DNA and morphology of teliospores and basidia. Our data indicate at least three species of Coleosporium occur on Solidago in North America, C. solidaginis, C. montanum comb. nov., which is proposed for the taxon that has commonly been identified as C. asterum in North America, and C. delicatulum, all of which can be differentiated by morphology of their basidia. In addition, the challenges of marker selection for molecular barcoding of rust fungi is discussed.     

Female response song in the ephippigerines Steropleurus stali and Platystolus obvius (Orthoptera,Tettigoniidae)

Stridulation by females of Steropleurus stali and Platystolus obvius in response to the calling song of the males was observed and recorded. The response has only been stimulated by the appropriate male song, either directly or from a recording. The structure of the files and the form of stridulation in both sexes is described. The male song of S. stali is remarkable in that only a few teeth on the file are struck in each wing movement. It is also notable that both opening and closing wing strokes contribute more or less equally to the syllable. The female song is similar but distinct. The song of P. obvius male is a single chirp involving nearly all the teeth on the file and with the main emphasis on the closing syllable. The response song of the female is a very brief chirp. These species are only sporadic singers, but when the female responds they are stimulated into greater activity. They thus contrast with reiterative singers like Ephippiger in which there is no female response. The implications of these contrasting behavioural patterns is discussed.     

Pollen tube reallocation in two preanthesis cleistogamous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae)

Pollen deposition on stigmas and pollen tube growth in two apocarpous species, Ranalisma rostratum and Sagittaria guyanensis ssp. lappula (Alismataceae), were examined with fluorescence microscopy. The reallocation of pollen tubes among pistils was observed in both species. The percentage of pollinated stigmas per flower was only 22.0% in R. rostratum and 51.0% in S. guyanensis, though the seed/ovule ratios are higher than 65% in both species. The number of pollen grains on each single stigma ranged from 0 to 96 in R. rostratum, and from 0 to 125 in S. guyanensis. When more than one pollen grain deposited on a stigma, all pollen tubes grew to the ovary, but only one of them turned towards the ovule and finally entered the nucleus. The other tubes grew through the receptacle tissue into ovules of adjacent carpels whose stigmas were unpollinated or pollinated later. The intercarpellary growth of pollen tubes could be a mechanism to increase the efficiency of sexual reproduction in an apocarpous gynoecium with low pollination on the pistils.     

Lessepsian invasion without bottleneck: example of two rabbitfish species (Siganus rivulatus and Siganus luridus)

Since the opening of the Suez Canal in the 19th century, a growing number of teleosts species have become permanently established in the eastern Mediterranean. As environmental parameters in the Mediterranean are very different from those in the Red Sea, there is an opportunity to evaluate the gene flow associated with the acclimatisation of these species to their new environment. Initial colonisation may have been restricted to individuals with marginal genotypes compared to populations of the Red Sea, eventually better adapted to the Mediterranean environment. Alternatively, colonisation may have occurred without major genetic differentiation, due to a large flux of immigrants and a continuous gene flow from the populations of origin. Using different molecular genetic techniques (mitochondrial DNA, Exon-Primed Intron-Crossing PCR amplification (EPIC) and Inter-Simple Sequence Repeats (ISSRs), patterns of genetic differentiation on both sides of the Suez isthmus were tested on two Lessepsian rabbitfish species (Siganus rivulatus and Siganus luridus). The absence of genetic differentiation between Mediterranean and Red Sea populations in both species showed that a great number of migrants participated to the colonisation of the Mediterranean, excluding any bottleneck event. This colonisation success suggests large eco-physiological plasticity in S. rivulatus and S. luridus that allowed them to thrive in the new environment.     

Vibration communication in orthopteroid insects (Orthoptera) from suborder Caelifera

A review of vibration communication in suborder Caelifera is made. The vibration communication channel is found in three superfamilies—Tetrigoidea, Eumastacoidea and Acridoidea. The presence of vibration communication in Pyrgomorphoidea and Tridactyloidea is suggested. The data on vibration signals in superfamilies Pneumoroidea, Tanaoceroidea and Trigonopterygoidea are not known.     

雏蝗属黑翅亚属两种雏蝗染色体核型的比较研究

采用常规染色体制片方法,对雏蝗属黑翅亚属的黑翅雏蝗(Chorthippus(Megaulacobothrus)aethalinus(Zub.))和中华雏蝗(Ch.(M.)chinensis Tarb.)的染色体核型进行了分析比较,结果表明,两种雏蝗的染色体数目均为2n(♂)=17=16+XO;常染色体为中部着丝粒(m,6条)和端部着丝粒(t,10条)两种类型,性染色体类型为端部着丝粒,二者的相似性显示出该属的基本特征。但两种雏蝗的核型公式和染色体的相对长度组成则不相同,黑翅雏蝗K(2n,♂)=6m+11t=6L+6M+4S+XO;中华雏蝗K(2n,♂)=6m+11t=6L+8M+2S+XO。而且,二种雏蝗的性染色体位次及相对长度也有明显差异:黑翅雏蝗的性染色体位于第五位,相对长度为8.33%,而中华雏蝗的则位于第八位,相对长度为5.53%。由此看出,二种雏蝗不同物种间存在的不同遗传特征。     

Sexual selection for intermediate optimum in Chorthippus brunneus (Orthoptera: Acrididae)

Individual males of the grasshopper, Chorthippus brunneus, differ significantly in several components of their calling songs which are used to attract and stimulate females. In a ‘round robin’ experiment involving 21 males, the variance in male mating success was greater than expected by chance. Males were ranked and correlations were sought between this rank and characteristics of the males. A significant negative correlation was found between rank and deviation of individual males from the overall mean syllable length, indicating stabilizing selection on this character, which may be involved in species recognition. In individual competitions between males there was a tendency for the more actively singing male to mate with the female.     

Vocal communication in two lemming species (Lagurus lagurus and Eolagurus luteus)

The vocal repertoire of steppe (Lagurus lagurus Pallas, 1773) and yellow steppe (Eolagurus luteus Eversmann, 1840) lemmings consists of only one type of signal, namely, a squeak. The signal does, however, have considerable variability. The DFA standard procedure shows the significant differences in the parameters of squeaks between species and significant differences in squeak parameters between the sexes in steppe lemming but not in the yellow steppe lemming. The fundamental frequency of the smaller steppe lemming’s squeak is higher than that of the larger yellow steppe lemming, although the peak frequencies have comparable values. In addition, the steppe lemming displays a pronounced sexual dimorphism in vocalization parameters; the frequency characteristics of the signals of the smaller females have lower values, which are contrary to scaling laws, stating that smaller individuals tend to have higher fundamental and peak frequencies. The age-related variability in the signals of yellow steppe lemmings was also described. The fundamental frequency of their squeaks is higher than that of the adults, but the peak frequency of signals in young and adults is not distinguished, and its value is higher than theoretically calculated. Such deviation in signal frequency parameters from the optimum may be result of directed selection, indicating the high value of such signals in the acoustic communication of lemmings.