Wing-coupling apparatus of Auchenorrhyncha (insecta : Homoptera)

We carried out SEM studies of the wing-coupling apparatus (WCA) of 33 species of Auchenorrhyncha (Homoptera) belonging to 15 families. The main structure of this apparatus always has a wing-coupling forefold (WCFF) on the claval margin of the mesothoracic wings and a similar, longitudinal wing-coupling hindfold (WCHF) or shorter wing-coupling lobe (WCL) or wing-coupling hook (WCH) on the costal margin of the metathoracic wings. We believe that the differences in the morphology of the microsculptures present on the various parts of the WCA (in addition to the shape and size of the WCFF, WCHF, WCL and WCH) may be used as systematic characteristics at least up to the generic level.     

Pure-tone vibrational signals in small Auchenorrhyncha (Homoptera)

Investigation of vibrational calling signals of about 500 species of small Auchenorrhyncha from Russia and adjacent territories has shown that more than 10% of the species studied produce signals fully or partially consisting of pure-tone components. Among these species, there are forms dwelling on various substrates including thick tree branches, slender twigs, grass stems, petioles, and leaves. Therefore, it is impossible to associate the presence of pure-tone signals in any species with the physical properties of the inhabited substrate. Pure-tone signals were recorded both in the largest and the smallest forms. Consequently, the type of signal frequency spectrum is not related to the insect size. Experiments under natural conditions confirm the assumption that pure-tone signals are more resistant to noise than wide-band ones. This property may compensate for the disadvantage of pure-tone signals arising from stronger attenuation in certain substrates. As a result, neither pure-tone nor noise signals give unambiguous advantages for vibrational communication. Since the carrier frequency of pure-tone signals of small Auchenorrhyncha increases with temperature, it seems to be determined by the contraction frequency of tymbal muscles, rather than by the resonance properties of any cavity or cuticular structure. Regular frequency modulations occur in the signals of many species; moreover, the calling signals of some species include both pure-tone and noise components. In most of the species studied, “frequency tuning” of their signals to the physical properties of a particular substrate is impossible because of the presence of frequency modulations, temperature-related variation in the carrier frequency, or the wide host range and the absence of strong preference for any particular plant organ. Sympatric species may differ in the carrier frequency of their pure-tone signals. If the signals occupy the same frequency range they sometimes differ in their frequency modulation pattern. Consequently, conspecific signal recognition not only by amplitude, but also by frequency pattern is possible in this case, which increases the efficiency of intraspecific communication.     

Migration of leafhoppers (Homoptera: Auchenorrhyncha) into a new polder

Auchenorrhyncha of a new polder were sampled by different kinds of traps in four stations in new habitats, one station on the salt marsh and one just outside the polder. In the latter stations 20 species of Auchenorrhyncha were caught in numbers that declined during the four year study. The proportion of macropters of the common Streptanus sordidus was highest in the largest catches. In the polder proper 392 specimens of 13 species were caught, all had moved at least 1500 m, but some could be traced to origins at greater distances. The number of immigrants also declined during the study. The distribution of the leafhoppers over the trapping stations suggests that leafhoppers, although sometimes transported over great distances, as a rule quickly fall out once they are airborne. Probably only one species had founded a resident population in the new polder at the end of the study.     

Partitioning of resources by grassland leafhoppers (Auchenorrhyncha, Homoptera)

Abstract. 1. Resource utilization of time (i.e. seasonal occurrence of adults) and oviposition sites (i.e. heights of the host plant above ground level) have been analysed in five species of leafhoppers commonly associated with the grass Holcus mollis.
2. The d/w method proposed by May & MacArthur (1972) has been used and when the values for the two resources are examined together it becomes apparent that much potential competition for oviposition sites is reduced by segregation in time. Moreover, potential competition for common resources is reduced by mobility and dispersal of some species.     

Direct and indirect effects of climate change on insect herbivores: Auchenorrhyncha (Homoptera)

1. Novel manipulations of local climate were employed to investigate how warmer winters with either wetter or drier summers would affect the Auchenorrhyncha, a major component of the insect fauna of grasslands. Direct and indirect effects of climate manipulation were found.
2. Supplemented summer rainfall resulted in an increase in vegetation cover, leading to an increase in the abundance of the Auchenorrhyncha.
3. Summer drought, however, caused a decrease in vegetation cover, but this did not lead to a corresponding decrease in the abundance of the Auchenorrhyncha.
4. Egg hatch and the termination of nymphal hibernation occurred earlier in winter warmed plots; however, the rate of nymphal development was unaffected.     

Modern classification and distribution of the family Issidae Spinola (Homoptera,Auchenorrhyncha: Fulgoroidea)

The modern classification of the family Issidae s. str. is presented according to which the family consists of 3 tribes: Issini, Hemisphaeriini, and Parahiraciini and comprises a total of 994 species and subspecies in 159 genera. The largest tribe, Issini, is distributed worldwide and comprises 129 genera with 755 species and subspecies. The tribes Hemisphaeriini and Parahiraciini are much smaller and mostly distributed in the Indo-Malayan Realm with some taxa also present in the Eastern Palaearctic and the Oceania. The tribe Hemisphaeriini consists of 15 genera with 187 species and subspecies while Parahiraciini includes 14 genera with 38 species. The Palaearctic and Indo-Malayan Realms have the richest faunas of Issidae. In contrast, Equatorial Africa has a very poor fauna of the family, whereas the Australian fauna is still almost undescribed. Chimetopon camerunensis Schmidt is recorded for the first time from Central African Republic and Gabon, and Sarima erythrocyclos Fennah, from Taveuni Island (Fiji).     

Gall formation by a spittlebug, Aphelaenus nigripectus (Aphrophoridae: Auchenorrhyncha; Homoptera)

Few spittlebug species are gall formers, but the Homoptera as a whole contain many gall‐forming species in many families. Nymphs of a spittlebug, Aphelaenus nigripectus (Aphrophoridae, Auchenorrhyncha, Homoptera), were observed to induce leaf‐roll galls on cherry trees (Prunus speciosa, P. × yedoensis and P. pendula cv. pendula (Rosaceae)) in late April in Kyoto, Japan. Aphelaenus nigripectus nymphs aggregated on the ventral surface of the young leaves, fed on the ventral (abaxial) midvein, and excreted masses of froth in the rolled leaves. In a field experiment, it was discovered that feeding of A. nigripectus nymphs can induce rolling of the cherry leaves, and that the rolled leaves may provide protection from desiccation to A. nigripectus nymphs. This is the first record of gall‐forming habits in Japanese spittlebugs.     

Paraphyly of Homoptera and Auchenorrhyncha inferred from 18S rDNA nucleotide sequences

Evolutionary affiliations of eighteen families of Hemiptera (s.l.) are inferred using molecular phylogenetic analysis of nucleotide (nt) sequences of 18S rDNAs. Exemplar taxa include: Archaeorrhyncha (=Fulgoromorpha): flatid, issid, dictyopharid, cixiid and delphacid; Prosorrhyncha (=Heteropterodea): Peloridiomorpha (=Coleorhyncha) -peloridiid, Heteroptera gerrid, lygaeid and mirid; Clypeorrhyncha [=extant (monophyletic) cicadomorphs]: cicadid, cercopoids (cercopid, aphrophorid), membracid and cicadellids (deltocephaline and cicadelline); and Sternorrhyncha: psyllid, aleyrodid, diaspidid and aphid. Analysed sequences encompass a region beginning ?550 nucleotides (nts) from the 5'-end to ?200 nts upstream from the 3'-end of the gene [?1150 base pairs (bp) in euhemipteran to >1400 bp in sternorrhynchan taxa]. Maximum parsimony and bootstrap analyses (PAUP) identify four principal hemipteran clades, Stenorrhyncha, Clypeorrhyncha, Archaeorrhyncha and Prosorrhyncha. These lineages are identified by synapomorphies distributed throughout the gene. Sternorrhyncha is a sister group to all other Hemiptera (i.e. Euhemiptera sensu Zrzavy), rendering Homoptera paraphyletic. Within Euhemiptera, clades Clypeorrhyncha, Archaeorrhyncha, Prosorrhyncha and Heteroptera are supported by one, three, two and three synapomorphic sites, respectively. There is equitable parsimonious inference for Archaeorrhyncha as the sister group to Prosorrhyncha (Neoherriiptera sensu Sorensen et al.) or Clypeorrhyncha, in either case rendering Auchenorrhyncha paraphyletic. Neohemiptera is supported by one synapomorphy. Within Clypeorrhyncha, clade cicada + cercopoids is the sister group of the clade cicadellids + membracid (Membracoidea sensu Dietrich & Deitz). Among archaeorrhynchans, clade delphacid + cixiid is the sister group of the clade dictyopharid + flatid + issid. Within Prosorrhyncha, the peloridiid is sister to the Heteroptera. Within Heteroptera, gerrid is the sister group of the clade mirid + lygaeid (Panheteroptera sensu Schuh). Based on secondary structure of synonymous 18S rRNA, two synapomorphies each of Sternorrhyncha, Prosorrhyncha and Heteroptera are compensatory substitutions on stem substructures. All other synapomorphies identifying major lineages of Hemiptera are noncompensatory substitutions on either bulges or stems. Short basal internodal distances suggest radiation of hemipteran lineages at the suborder level occurred rapidly. Morphological, palaeoentomological and eco-evolutionary factors supporting the 18S rDNA-based phylogenetic tree are discussed.     

Impact of Bemisia argentifolii (Homoptera: Auchenorrhyncha: Aleyrodidae) infestation and squash silverleaf disorder on zucchini yield and quality

Fruit yield and quality of zucchini, Cucurbita pepo L., plants infested with Bemisia argentifolii Bellows & Perring were evaluated in a screenhouse under spring and fall growing conditions by using closely related sister lines that were either susceptible (ZUC61) or tolerant (ZUC76-SLR) to squash silverleaf disorder. Our objective was to test separately the effects of level of whitefly infestation and expression of silverleaf symptoms on zucchini yield and quality. In a second experiment, yield and quality of fruit produced by silverleaf-tolerant zucchini genotypes incorporating two different sources of tolerance (ZUC76-SLR and ZUC33-SLR/PMR) were compared with that of 'Zucchini Elite', a silverleaf-susceptible commercial hybrid. Zucchini fruit yield was reduced in plants exposed to repeated infestations of whiteflies in spring and fall of both experiments. In addition, fruit grew to harvestable size more slowly under the highest whitefly infestations. Fruit quality was reduced at high infestations because of uneven and reduced pigmentation. The fruit yield and quality of ZUC61 and ZUC76-SLR were similarly affected by whitefly infestation despite differences in their susceptibility to squash silverleaf disorder. Fruit from infested plants showed decreased levels of chlorophyll and carotenoids causing the "blanching" of the fruit that is associated with loss of quality and reduced marketability. Leaves of infested plants of all genotypes had reduced levels of photosynthetic and photoprotectant pigments, possibly leading to reduced photosynthesis and consequently reduced yield. We conclude that feeding by high whitefly populations rather than expression of squash silverleaf disorder is responsible for yield and quality reduction in zucchini.     

Postembryonic development of the auditory system of the cicada Okanagana rimosa (Say) (Homoptera: Auchenorrhyncha: Cicadidae)

Cicadas (Homoptera: Auchenorrhyncha: Cicadidae) use acoustic signalling for mate attraction and perceive auditory signals by a tympanal organ in the second abdominal segment. The main structural features of the ear are the tympanum, the sensory organ consisting of numerous scolopidial cells, and the cuticular link between sensory neurones and tympanum (tympanal ridge and apodeme). Here, a first investigation of the postembryonic development of the auditory system is presented. In insects, sensory neurones usually differentiate during embryogenesis, and sound-perceiving structures form during postembryogenesis. Cicadas have an elongated and subterranian postembryogenesis which can take several years until the final moult. The neuroanatomy and functional morphology of the auditory system of the cicada Okanagana rimosa (Say) are documented for the adult and the three last larval stages. The sensory organ and the projection of sensory afferents to the CNS are present in the earliest stages investigated. The cuticular structures of the tympanum, the tympanal frame holding the tympanum, and the tympanal ridge differentiate in the later stages of postembryogenesis. Thus, despite the different life styles of larvae and adults, the neuronal components of the cicada auditory system develop already during embryogenesis or early postembryogenesis, and sound-perceiving structures like tympana are elaborated later in postembryogenesis. The life cycle allows comparison of cicada development to other hemimetabolous insects with respect to the influence of specially adapted life cycle stages on auditory maturation. The neuronal development of the auditory system conforms to the timing in other hemimetabolous insects.     

The Distribution of Grassland Auchenorrhyncha Assemblages (Homoptera: Cercopidae, Cicadellidae, Delphacidae) in Northern England and Scotland

The distribution of Auchenorrhyncha species assemblages on 174 grassland sites in northern England and Scotland was investigated using ordination and classification techniques. Altitude appeared to be the most important environmental variable influencing assemblage distribution but the effects of altitude on soil type and moisture, and on plant composition, either herbaceous or woody, and structure were likely to have been primary influences. The main differences between sites in the eight habitat groups of the classification were products of these soil and plant variables, with the geographical position of sites in the survey area having less of an effect on site classification. A considerable number of nationally and regionally rare and scarce species were recorded. The results indicate that Auchenorrhyncha could be used in site conservation based on invertebrate species assemblages and rare species distribution but that more information is required to assess both habitat diversity and species rarity. More survey work would also be required to identify appropriate site management procedures for the conservation of Auchenorrhyncha within an overall programme for terrestrial invertebrates.     

Cladistic analysis of Coenosiini (Diptera: Muscidae: Coenosiinae)

The phylogenetic relationships among world genera of Coenosiini (Diptera: Muscidae: Coenosiinae) were investigated using parsimony. The analysis involved forty‐six ingroup terminal taxa, representing 100% of the genera currently assigned to this tribe, three outgroups and sixty‐seven adult male and female morphological characters. The monophyly of Coenosiini is confirmed by the position of the three katepisternal bristles, equidistant from each other and placed at the points of an equilateral triangle. Genera Andersonosia, Agenamyia, Anthocoenosia, Drepanocnemis, Pachyceramyia and Rhabdotoptera are removed from Coenosiini and temporarily placed in Limnophorini. The other genera fall into two groups: the Lispocephala‐group, comprised of genera with mainly Old World species and the Nearctic genus Pentacricia; and the Coenosia‐group, with the highest level of generic diversity in South America. Each group is defined by synapomorphies of its constituent genera: Lispocephala‐group by the presence of a posteroventral apical seta on the hind tibia, the presence of two arms in male sternite 6 (not forming a ring) and the short or very short female ovipositor; the Coenosia‐group by the presence of a developed epiproct and narrow sternites 6 and 7 of the female ovipositor. The following new generic synonymies are proposed (junior synonyms in parentheses): Lispocephala Pokorny (=Pectiniseta Stein), Coenosia Meigen (=Tenuicosta Stein; Dexiopsis Pokorny), Neodexiopsis Malloch (=Haroldopsis Albuquerque), Pilispina Albuquerque (=Levallonia Albuquerque; Noelia Albuquerque; Parvomusca Medeiros; Cholomyioides Albuquerque), Apsil Malloch (=Raymondomyia Malloch), Stomopogon Malloch (=Angolia Malloch; Angolina Pont) and Pygophora Schiner (=Chouicoenosia Cui & Xue).     

Fine structure of the eggshell of Ommatissus binotatus Fieber (Homoptera,Auchenorrhyncha, Tropiduchidae)

The external morphology and fine structure of the eggshell of Ommatissus binotatus Fieber (Homoptera : Tropiduchidae) was investigated by light, scanning and transmission electron microscopy. The egg surface has 2 main regions: a specialized area and an unspecialized egg capsule. The specialized area is characterized by a large respiratory plate containing the operculum and a short respiratory horn. The latter consists of an external hollow tube and an internal coneshaped projection hosting a micropylar canal. The eggshell has 4 layers: the vitelline envelope, a wax layer, the chorion and an outer mucous layer. The chorion has inner, intermediate and outer parts. The functions of the different parts of the eggshell are discussed. Characters useful to define the eggs and the oviposition habit in the family Tropiduchidae were provided. The size and morphology of the egg, plate, respiratory horn and operculum are suggested as useful characters for ootaxonomic analysis.     

Cladistic analysis of Taxaceae s. l.

Taxaceae s. l. is a wider concept of classification treating five genera of Taxaceae s. str. and Cephalotaxus together. Cephalotaxus is morphologically very similar to the five genera of Taxaceae s. str. Various models of classification for six genera have already been published. However, the phylogenetic position and genuine relationships of these genera and species are still confusing. A cladistic analysis of Taxaceae s. l. has been carried out to resolve the problem existing in their phylogeny and to provide a new approach regarding the relationships of these six genera. Parsimony analyses were based on 28 characters and eight genera including two outgroups Agathis and Sciadopitys. The most parsimonious tree retained with branch length 38 and 194 rearrangement trials. Consistency index was 0.68 and retention index was 0.66. Principally, two main clades were found: one represented by Austrotaxus forming the base of the tree and another by the remaining five genera. Taxus + Pseudotaxus clade split after Austrotaxus, and Cephalotaxus was sister to Torreya + Amentotaxus clade. Taxus + Pseudotaxus clade was supported by the highest bootstrap value. Finally, cladistic analysis does not support existence of Cephalotaxaceae. Therefore, it would be better to classify Cephalotaxus within Taxaceae s. l. with the other five genera.     

Cladistic analysis of Omalodini Kryzhanovskij (Coleoptera: Histeridae: Histerinae)

According to the current Histeridae classification, Omalodini is composed of 100 species described in 12 genera distributed in the Neotropical, Afrotropical, Afrotemperate and Oriental regions: Asolenus Lewis; Atribalus Bickhardt; Blypotehus Vienna, Ebonius Lewis; Lewisister Bickhardt; Notolister Lewis; Omalodes Erichson, divided in Omalodes (Omalodes), O. (Diplogrammicus) Lewis and O. (Cornillus) Lewis; Perfidolenus Vienna; Rhypochares Marseul; Scapomegas Lacordaire; Sphyracus Marseul; Theropatina Mazur. Our aims were to test the monophyly of Omalodini, using cladistic analysis, and propose a hypothesis of the phylogeny of the tribe. The matrix was composed of 49 terminal taxa (34 from the ingroup and 15 from the outgroup) and 131 characters of the adult morphology. The data were analysed under equal weights and implied weights. In both analyses, Omalodini represents a polyphyletic group and the trees obtained from equal weights analysis (two most parsimonious trees) were chosen in order to recover the tribe's monophyly. We recognize three lineages in Omalodini: Ebonius, undescribed genus and Omalodes, being supported by six transformations (Ebonius + (undescribed genus + Omalodes)). The sister group of Omalodini was defined as a clade composed of Histerini, Platysomatini and Hololeptini. The subgenera of Omalodes were not resolved consistently under different implied weight analyses. It is necessary to emphasize that Omalodes (Omalodes) comprises the largest group of Omalodini and requires an analysis with better sampling for more precise resolution of the internal phylogeny of the genus. The groups excluded a posteriori from Omalodini, Theropatina, Asolenus, Atribalus, Blypotehus, Lewisister, Notolister, Perfidolenus, Rhypochares, Sphyracus and Scapomegas, could not be allocated to any of the existing tribes of Histerinae.