Perception of cuticular hydrocarbons by the olfactory organs in Periplaneta americana (L.) (Insecta: Dictyoptera)

Despite the importance of cuticular hydrocarbons (CHs) in insect chemical communication, direct proof that they are detected and recognized by insects by contact or by olfactory receptors are rare. In Periplaneta americana, CHs induce aggregation. The aim of our study was to investigate how CHs are detected by P. americana antennae. Using solid phase microextraction and gas chromatography, the three main CHs of the species profile were identified in the volatiles emitted by these insects. Gas chromatography coupled to electroantennography recordings demonstrated that the antennae responded to these three CHs. Furthermore, CHs had an attraction effect in Y-olfactometer bioassays when presented at high concentrations. As CHs can be perceived by P. americana, at least from a short distance, they could play a role in attracting conspecifics during aggregation processes, in addition to inducing aggregation when direct contact is possible.     

Synaptic connections of the Nervus connectivus in the frontal ganglion of Periplaneta americana L. (Insecta)

Summary The course of the Nervus connectivus (N.c.), its branches, and synaptic connections within the frontal ganglion (FG) were investigated electron microscopically after cobalt iontophoresis of the N.c. The subsequent treatment of ultrathin sections with Timm's method was found to be very suitable for identifying the smallest branches. In the neuropil, fibers of the N.c. form Gray-I-type synapses, but also dyads are abundant, whereby the N.c. fibers occur exclusively in postsynaptic position with neurosecretory fibers. The possible role of these relationships is discussed.Dedicated to the 70th birthday of Prof. Dr. Manfred GerschThe authors wish to thank Mrs. B. Cosack for excellent technical assistance     

Croatian mayflies (Insecta,Ephemeroptera): species diversity and distribution patterns

Knowledge of the mayfly biodiversity in the Balkan Peninsula is still far from complete. Compared to the neighbouring countries, the mayfly fauna in Croatia is very poorly known. Situated at the crossroads of central and Mediterranean Europe and the Balkan Peninsula, Croatia is divided into two ecoregions: Dinaric western Balkan and Pannonian lowland. Mayflies were sampled between 2003 and 2013 at 171 sites, and a total of 66 species was recorded. Combined with the literature data, the Croatian mayfly fauna reached a total of 79 taxa. Of these, 29 species were recorded for the first time in Croatia while 15 species were not previously recorded in Dinaric western Balkan ecoregion. Based on the mayfly assemblage, sampling sites were first structured by ecoregion and then by habitat type. In comparison with the surrounding countries, the Croatian mayfly fauna is the most similar to the Hungarian and Bosnian fauna. Some morphologically interesting taxa such as Baetis cf. nubecularis Eaton, 1898 and Rhithrogena from the diaphana group were recorded. Ephemera cf. parnassiana Demoulin, 1958, the species previously recorded only from Greece, was also recorded.     

Two new species of genus Rhopalopsole (Insecta, Plecoptera, Leuctridae) from China

Two new species of Rhopalopsole Klapálek from China are described: Rhopalopsole exiguspina Du & Qian, sp. n. and Rhopalopsole ampulla Du & Qian, sp. n., which were collected in Guizhou province, China.     

Cuticular waxes from potato (Solanum tuberosum) leaves

The qualitative and quantitative compositions of leaf cuticular waxes from potato (Solanum tuberosum) varieties were studied. The principal components of the waxes were very long chain n-alkanes, 2-methylalkanes and 3-methylalkanes (3.1-4.6 microg cm(-2)), primary alcohols (0.3-0.7 microg cm(-2)), fatty acids (0.3-0.6 microg cm(-2)), and wax esters (0.1-0.4 microg cm(-2)). Methyl ketones, sterols, beta-amyrin, benzoic acid esters and fatty acid methyl, ethyl, isopropyl and phenylethyl esters were found for the first time in potato waxes. The qualitative composition of the waxes was quite similar but there were quantitative differences between the varieties studied. A new group of cuticular wax constituents consisting of free 2-alkanols with odd and even numbers of carbon atoms ranging from C25 to C30 was identified.     

Two new species of the stonefly genus Amphinemura (Insecta,Plecoptera, Nemouridae) from China

Two new species of the genus Amphinemura Ris from China are described and illustrated, i.e. A. annulata Du & Ji, sp. n. from Zhejiang, Shanxi, Shaanxi and Guizhou Province, and A. lingulata Du & Wang, sp. n. from Shaanxi and Sichuan Province. A. annulata is similar to A. tricintusidens Wang & Zhu in having an apical cavity of the epiproct, but the epiproct ventral sclerite and the median paraproct lobe of the two species are different. A. lingulata is related to A. didyma Zhu & Yang in having the similar epiproct, but they differ mostly in paraproct median and outer lobes.     

Ultrastructural Variation of Cuticular Layers in Cephalobinae (Nemata: Rhabditida)

The ultrastructure of the body wall cuticle in Acrobeles complexus, Cervidellus alutus, and Zeldia punctata was studied as a step toward understanding biological diversity within Cephalobinae, and to discover new characters for phylogeny-based classification of the suborder. In each species the cuticle consists of cortical, median, and basal layers. The cortical layer includes an external trilaminate and internal granular zone; the basal layer is striated. In Z. punctata the median layer is electron-lucent, vacuolar, and penetrates the cortical layer; it also includes periodically dense columns that apparently correspond to punctuations visible with light microscopy. In contrast, the median layer of the body wall cuticle in A. complexus and C. alutus is bisected by a zone that undulates parallel to the nematode surface and with periodicity corresponding to annuli. Phylogenetic analysis, using derived cuticle patterns of Cephalobinae, requires an understanding of ecological pressures that could result in convergent evolution of cuticle characters.     

Differences in penetration routes and establishment rates of four entomopathogenic nematode species into four white grub species

We compared the penetration of the entomopathogenic nematodes Steinernema scarabaei (AMK001 strain), S. glaseri (NC1 strain), Heterorhabditis zealandica (X1 strain), and H. bacteriophora (GPS11 strain) into third-instars of the scarabs Popillia japonica, Anomala orientalis, Cyclocephala borealis, and Rhizotrogus majalis. When larvae were exposed to nematodes for 6-72 h larval mortality and nematode establishment rate and occasionally speed of kill often showed the same pattern within nematode-white grub combinations. But no two nematodes or white grub species had the same pattern for these observations for all white grub or nematode species, respectively. Mortality, establishment, and speed of kill followed a similar pattern for H. zealandica, S. glaseri, and S. scarabaei, but there was no clear relationship for H. bacteriophora. Significant nematode establishment was only observed after at least 48 h exposure in most nematode-white grub combinations. Faster establishment was observed only for H. zealandica in A. orientalis and R. majalis (after 24 h) and for S. scarabaei in P. japonica and R. majalis (after 12 h). Nematode establishment after 72 h in the different scarab species was generally low for S. glaseri (<1.5%) and H. bacteriophora (<3%), higher for H. zealandica (2-5%), and the highest for S. scarabaei (1-14%). However, in another experiment establishment was generally higher after 96h exposure. Nematode penetration sites were determined by comparing nematode establishment in larvae with mouth, anus, mouth+anus, or none sealed with glue. The trends for each nematode species were very similar in the different white grub species. H. zealandica and H. bacteriophora showed excellent cuticular penetration ability but may also penetrate through mouth and/or anus. S. glaseri also penetrated through the cuticle but lower establishment in larvae with mouth or mouth+anus sealed suggested that the mouth is an important penetration site. S. scarabaei showed a preference for the mouth as a penetration site, but it showed some cuticular penetration ability and may also use the anus as a penetration site. The methodology used cannot exclude that cuticular penetration also included penetration through the spiracles. To fully understand the effect of nematode and white grub species on nematode virulence, future studies will have to compare host immune response to the penetrating IJs and the role of the symbiotic bacteria in these interactions.     

The frontal ganglion of Periplaneta americana L. (insecta)

Summary The frontal ganglion, part of the stomatogastric nervous system, contains about 60 to 80 neurons, 25 to 30 m in diameter. A well developed Golgi system, producing dense-core vesicles, lysosomes, multivesicular bodies and dense bodies are abundant. Glia elements are sparsely distributed. Many nerve fibres contain granules of different size and electron density. Five groups of fibres can be distinguished: Fibres with granules of about 200 nm (type A), fibres with granules of about 160 to 170 nm (type B), fibres with granules of about 80 to 100 nm (type C) and those with synaptic vesicles of 50 nm (type D) respectively. A fifth very small type contains neither vesicles nor granules. Special attention was paid to synaptic contacts. The divergent dyad seems to be the main type in the frontal ganglion. Frequently, neurosecretory endings are observed in presynaptic position. Immunocytochemical staining of neurosecretory material closely corresponds to the distribution of type A fibres, as observed electron microscopically. Immunoelectrophoresis of extracts from frontal ganglia with polyspecific anti-neurosecretion-serum reveals a single precipitation line, indicating that the immunocytochemical localization of neurosecretory material is due to reaction with a specific as well as a crossreagent antibody.Supported by the Ministerium für Wissenschaft und Technik der DDRThe authors wish to thank Mrs. B. Cosack and Mrs. A. Schmidt for excellent technical assistance     

Two new genera and two new species of Mantophasmatodea (Insecta, Polyneoptera) from Namibia

Two new species and two new genera (Pachyphasma, Striatophasma) of Mantophasmatodea are described from Namibia. Pachyphasma brandbergense is endemic to the Brandberg massif; Striatophasma occupies an extensive area south of the region inhabited by Mantophasma. Phylogenetic analyses (see Predel et al. in press) suggest a sistergroup relationship of Striatophasma and the South African Austrophasmatidae.     

Discovery of an unknown diversity of Leucinodes species damaging Solanaceae fruits in sub-Saharan Africa and moving in trade (Insecta,Lepidoptera, Pyraloidea)

The larvae of the Old World genera Leucinodes Guenée, 1854 and Sceliodes Guenée, 1854 are internal feeders in the fruits of Solanaceae, causing economic damage to cultivated plants like Solanum melongena and Solanum aethiopicum. In sub-Saharan Africa five nominal species of Leucinodes and one of Sceliodes occur. One of these species, the eggplant fruit and shoot borer Leucinodes orbonalis Guenée, 1854, is regarded as regularly intercepted from Africa and Asia in Europe, North and South America and is therefore a quarantine pest on these continents. We investigate the taxonomy of African Leucinodes and Sceliodes based on morphological characters in wing pattern, genitalia and larvae, as well as mitochondrial DNA, providing these data for identification of all life stages. The results suggest that both genera are congeneric, with Sceliodes syn. n. established as junior subjective synonym of Leucinodes. Leucinodes orbonalis is described from Asia and none of the samples investigated from Africa belong to this species. Instead, sub-Saharan Africa harbours a complex of eight endemic Leucinodes species. Among the former nominal species of Leucinodes (and Sceliodes) from Africa, only Leucinodes laisalis (Walker, 1859), comb. n. (Sceliodes) is confirmed, with Leucinodes translucidalis Gaede, 1917, syn. n. as a junior subjective synonym. The other African Leucinodes species were unknown to science and are described as new: Leucinodes africensis sp. n., Leucinodes ethiopica sp. n., Leucinodes kenyensis sp. n., Leucinodes malawiensis sp. n., Leucinodes pseudorbonalis sp. n., Leucinodes rimavallis sp. n. and Leucinodes ugandensis sp. n. An identification key based on male genitalia is provided for the African Leucinodes species. Most imports of Leucinodes specimens from Africa into Europe refer to Leucinodes africensis, which has been frequently imported with fruits during the last 50 years. In contrast, Leucinodes laisalis has been much less frequently recorded, and Leucinodes pseudorbonalis as well as Leucinodes rimavallis only very recently in fruit imports from Uganda. Accordingly, interceptions of Leucinodes from Africa into other continents will need to be re-investigated for their species identity and will likely require, at least in parts, revisions of the quarantine regulations. The following African taxa are excluded from Leucinodes: Hyperanalyta Strand, 1918, syn. rev. as revised synonym of Analyta Lederer, 1863; Analyta apicalis (Hampson, 1896), comb. n. (Leucinodes); Lygropia aureomarginalis (Gaede, 1916), comb. n. (Leucinodes); Syllepte hemichionalis Mabille, 1900, comb. rev., Syllepte hemichionalis idalis Viette, 1958, comb. rev. and Syllepte vagans (Tutt, 1890), comb. n. (Aphytoceros). Deanolis iriocapna (Meyrick, 1938), comb. n. from Indonesia is originally described and misplaced in Sceliodes, and Leucinodes cordalis (Doubleday, 1843), comb. n. (Margaritia) from New Zealand, Leucinodes raondry (Viette, 1981), comb. n. (Daraba) from Madagascar as well as Leucinodes grisealis (Kenrick, 1912), comb. n. (Sceliodes) from New Guinea are transferred from Sceliodes to Leucinodes. While Leucinodes is now revised from Africa, it still needs further revision in Asia.     

Differences between the pathogenic processes induced by Steinernema and Heterorhabditis (Nemata: Rhabditida) in Pseudaletia unipuncta (Insecta: Lepidoptera)

Larvae of Pseudaletia unipuncta are moderately susceptible to infections caused by entomopathogenic nematodes, being a desirable host to study pathogenic processes caused by Heterorhabditis bacteriophora, Steinernema carpocapsae, and Steinernema glaseri and their associated bacteria. The ability of the infective stage of these nematodes to invade hosts is quite different. S. carpocapsae invades the highest number of insects and presents the highest penetration rate, followed by H. bacteriophora. Regression analysis between the number of insects parasitized and the number of IJs counted per insect, over time, showed a high correlation for S. carpocapsae whereas for H. bacteriophora it was low. Dose-response was most evident at a concentration below 100 IJs per insect on H. bacteriophora, whereas on S. carpocapsae it was found for doses ranging from 100 to 2,000 IJs. Student's t test analysis of dose-response showed parallel, yet unequal, slopes for both strains of H. bacteriophora, whereas distinct regressions were obtained for S. carpocapsae and S. glaseri, thus, evidencing each species develop a distinct pathogenic process. Insects injected with Photorhabdus luminescens died within 50 h after injection, whereas those treated with X. nematophila died much later. Moreover, the mortality in insects exposed to H. bacteriophora complex and injected with P. luminescens was close, but insects injected with bacteria died faster. Insect mortality in treatments with complexes S. carpocapsae and S. glaseri was significantly higher than that which was observed in insects injected with symbiotic bacteria.     

Cuticular hydrocarbon profiles as a taxonomic tool: advantages,limitations and technical aspects

Cuticular hydrocarbons (CHCs) are expressed on an insect's cuticle and are one of the major factors allowing insects to identify members of their own species, colony and gender. As a result of their species‐specificity, CHCs are increasingly used to delimit species in addition to more conventional methods, such as morphology or genetic markers, and so play an important role in chemotaxonomy. Species vary in the type of CHCs that they produce, as well as in the relative quantities of shared compounds. This review summarizes not only how taxonomists may differentiate between species based on CHC profiles, but also the incentive for using CHC composition as taxonomic tool. Benefits regarding the identification of cryptic species and early signs of reproductive isolation are then discussed, giving examples from studies of taxonomy, behaviour and biosynthesis. For taxonomic characters to reliably indicate species boundaries, their limitations need to be known. Potential problems caused by environmental effects, intra‐species variation in profiles and other technical issues are highlighted, and suggestions are made regarding their avoidance. It remains a challenge to determine the variation beyond which two species can be called independent; a problem shared by most methods of delimitation. Recently, there has been a shift towards using a combination of different taxonomic tools, both molecular and non‐molecular, to test observed species differences.     

New microsporidia parasitizing bark lice (Insecta: Psocoptera)

Two species of bark lice, Xanthocaecilius sommermanae Mockford and Polypsocus corruptus Hagen, collected in a canopy Malaise trap placed in Great Smoky Mountains National Park as part of a survey of the park’s fauna, were found to be infected with microsporidia. Diagnosis was originally based on light microscopy, and was confirmed by PCR amplification and electron microscopy. This is the first record of microsporidia infection in the insect order Psocoptera. Four morphological spore types corresponded to four original SSUrDNA sequences (Genbank accession no. FJ865221-24), suggesting infection with four microsporidia species. Two of those species were examined by electron microscopy. We describe here one new genus and two new species based on morphological and sequence data: Antonospora psocopterae sp. n. with elongated diplokaryotic spores, 4.4 ± 0.05 × 1.9 ± 0.03 μm and Mockfordia xanthocaeciliae gen. n. sp. n. with ovocylindrical monokaryotic spores, 2.5 ± 0.10 × 1.4 ± 0.02 μm. A. psocopterae displayed high sequence (95%) and structural similarity with Antonospora scoticae, fell within a well supported dichotomy with A. scoticae inside the Antonospora-Paranosema clade in phylogenetic analyses by NJ, PS and ML. M. xanthocaeciliae did not exhibit much sequence or structural similarity with any of known microsporidia species, except Encephalitozoon spp. M. xanthocaeciliae fell within one clade with Encephalitozoon spp. in phylogenies and shared with encephalitozoons structural resemblance and about 80% of SSUrDNA sequence identity. The other two species were not described and provisionally were placed to the collective genus Microsporidium as Microsporidium sp. 1 and Microsporidium sp. 4 from bark lice because of insufficient morphological data. The finding that samples fixed and stored for months in propylene glycol (“antifreeze”) are good enough for DNA sequence analysis and can be used for morphological analyses (if no better fixation alternatives are available), is promising for future surveys for microsporidia.     

On the Domene species of China,with descriptions of four new species (Coleoptera,Staphylinidae)

Material of the paederine genus Domene Fauvel, 1873 from China is examined. Nine species were identified, four of them described previously, one unnamed (represented exclusively by females), and four are newly described: Domene cultrata sp. n. (Gansu, Hubei, Shaanxi); Domene cuspidata sp. n. (Gansu, Shaanxi, Sichuan); Domene chenae sp. n. (Guangxi); Domene reducta sp. n. (Sichuan). A lectotype is designated for Domene reitteri Koch, 1939; a neotype is designated for Domene chenpengi Li, 1990. Domene dersuuzalai Gusarov, 1992 is placed in synonymy with Domene chenpengi. Previous records of two Japanese species from China are most likely based on misidentifications and considered erroneous. Thus, the Domene fauna of China is currently composed of twelve described species. A key to the Domene species of China is provided. The distributions of eleven species are mapped.     

Cuticular wax composition of Salix varieties in relation to biomass productivity

The leaf cuticular waxes of six Salix clones (one Salix miyabeana, one Salix dasyclados, one Salix eriocephala, two Salix purpurea, and one interspecific hybrid of Salix eriocephala x interior) with different biomass productivities were characterized by gas chromatography-mass spectrometry. Total wax content ranged from 6.3 to 16.8 microg cm(-2), and two distinct patterns of wax were measured. The wax from leaves of S. dasyclados 'SV1' differed from all other clones and was dominated by fatty acids (42%), high concentrations of n-alkanes (25%) and n-alcohols (28%), with low n-aldehyde content (4%). All other clones produced cuticular wax dominated by n-alcohols (32-51%), particularly 1-hexacosanol, with fatty acids (14-37%) and n-aldehydes (19-26%) present in lower abundances. Clones of Salix grown under identical environmental conditions produce noticeably different amounts of cuticular wax. In contrast to previous studies of Salix, total wax content was independent of biomass productivity, measured as basal area, suggesting that wax production is not directly linked with woody biomass production by shrub willows under these site conditions.