Tettigonia Viridissima Research Articles

Bio-insecticidal Efficacy of Beauveria bassiana Vuill. Strains against Tettigonia viridissima L. in Tobacco

The green grasshopper (Tettigonia viridissima L.) is a species which attacks tobacco plants. The purpose of the present study was to establish the bio-insecticidal efficacy of entomopathogenic fungi Beauveria bassiana Vuill. strains 214, 644, and 733 on the growth and development of T. viridissima in tobacco. The research was conducted under laboratory conditions. The study found insecticidal effects of the B. bassiana strains 214, 644, and 733 against T. viridissima. Surviving of larvae was monitored at 5-day intervals until the 15th day after treatment with a spore suspension of the tested Beauveria strains. The highest virulence of the tested fungi was shown by strain 644, followed by strains 214 and 733. On the 5th day after treatment, no efficacy against T. viridissima larvae was detected. On the 10th day post-treatment strain 644 showed 66.7% efficacy, while efficacy against larvae of grasshoppers for the other two strains 214 and 733 was significantly lower: 33.3%. Efficacy gradually increased and on the 15th day post-treatment 100% mortality of T. viridissima was observed for all isolates. The results obtained from the virulence test of B. bassiana 214, 644, and 733 ascertain their application as biocontrol agents in tobacco production under field conditions.

Bioacoustics of Tettigoniidae (Insecta, Orthoptera) Distributed in Hakkari (Eastern Anatolia) Province

In this study, the male calling songs of sixteen species belonging to the Tettigoniidae family distributed in Hakkari were recorded in the field studies and bioacoustic analyses were performed. The bioacoustic analysis of two genera (Kurdia and Novadrymadusa) documented first time with present study and in total six species (Bradyporus (Callimenus) latipes, Isophya hakkarica, Kurdia uvarovi, Novadrymadusa karabagi, Psorodonotus hakkari, and Squamiana supericola) were presented first time. The bioacoustic analyses of seven species (Conocephalus (Anisoptera) fuscus, Pezodrymadusa indivisa, Polysarcus zacharovi, Tettigonia armeniaca, Tettigonia caudata, Tettigonia viridissima, and Uvarovistia satunini) were examined for the first time from Hakkari populations. In addition, in this study, the bioacoustic analyses of three species (Apholidoptera kurda, Saga hakkarica, and Uvarovistia zebra) distributed in Hakkari were re-evaluated in this study on new individuals. As a result of the findings, it has been determined that the male calling song of sixteen species belonging to the Tettigoniidae family are species-specific, have a simple calling song type, and morphological species hypotheses are also supported by bioacoustic data (male calling song).

A case study – The occurrence of pests in stands of newly introduced energy crops in large-scale pilot experiments in conditions of Central Europe

Abstract The objective of this paper is to document the occurrence of pests recorded in a large-scale pilot field experiment, where a unique set of newly-introduced herbaceous energy crops was tested under conditions of eastern Slovakia. The set consisted of Elymus elongatus, Secale cereanum, Silphium perfoliatum, Galega orientalis, Sida hermaphrodita, Panicum virgatum, Amaranthus spp., Panicum miliaceum, Sorghum sudanense, and Sorghum bicolor. A total of 14 cultivars were tested on 4 sites during 4 crop years (2016 – 2020). At least 17 species of pests were recorded in total, as some of the species may represent the identity of the couple or several relative ones, which was rare only as usually a fower common species. The occurred pests list consists of Anisoplia lata Erichson, Agriotes lineatus L., Capreolus capreolus L., Deroceras agreste L., Oulema gallaeciana Heyden, Lepisma saccharinum L., Lepus europaeus Pallas, Meloe proscarabaeus L., Metcalfa pruinosa Say, Microtus arvalis Pallas, Philaenus spumarius L., Psylliodes chrysocephala L., Rhopalosiphum padi L., stemborers as any insect larva or arthropod boring into plant stem, Sus scrofa L., Aleyrodes proletella L., Tettigonia viridissima L., and Trialeurodes vaporariorum Westwood. Overall, the occurrence of pests was regular and scattered, and damages caused by them were negligible usually, but a total destruction of the crop stand even cultivar-specific was recorded too. Most of the meaningful pests are primarily field hunting animals and only secondarily commonly occurring insect species, which for further observations are desirable in order to capture the tendency of important pests’ overpopulation, confirming respectively. Although even rare finding of the single caterpillar of Xylena exsoleta exsoleta L. was recorded in a buffer zone, within the experiment no newly introduced pest species was recorded.

Effect of dramatic alteration of landscape structure on the Orthoptera assemblages of Transcarpathian lowland meadows (West Ukraine)

Traditional and extensively used agricultural lands maintain and protect high levels of biological diversity. This diversity is in decline due to land use intensification and abandonment. Natural and semi-natural grasslands of the Carpathian lowlands have become endangered over the 19th century. However, some remains of former wetlands have survived land use change in the Bereg Region (North-eastern Hungary and Eastern Ukraine). We surveyed Orthopterans as sensitive indicators of habitat structure and microclimate in grasslands. We identified three different Orthoptera assemblages and their character species. Although rare and especially valuable species were not found in the studied sites, the species rich remains of wetlands still protected relics of former wildlife of wetlands. Understanding the quantitative character of the assemblages, ratios of life forms and particularly co-occurrences of their character species (Chorthippus dorsatus, Leptophyes albovittata, Tettigonia viridissima and Ruspolia nitidula) and use of Grasshopper Conservation Indexes (GCI) can help to identify remaining good quality patches with highest conservation value and monitoring.Implications for insect conservationThe focused management of these habitats with reconsideration of the traditional water management can be effective practice for wetland management and Orthoptera conservation.

Bracken fern (Pteridium aquilinum (L.) Kuhn) overgrowth on dry Alpine grassland impedes Red List Orthoptera but supports local orthopteran beta diversity

The native bracken fern (Pteridium aquilinum (L.) Kuhn) has become increasingly invasive in abandoned or undergrazed Alpine grasslands. Bracken stands are generally assumed to be poor in species, but there is still very little information about the impact on the fauna. We recorded Orthoptera communities of 24 sample plots with varying bracken cover. Compared to plots with only sparse or medium bracken cover, species richness was highly significantly lower in densely overgrown plots, while the former two did not differ markedly. Multivariate ordination analyses revealed gradients with unequal orthopteran communities, showing distinct patterns of bracken cover clustering. Based on indicator values, 13 of 23 Orthoptera species turned out to be significantly or marginally significantly associated with a single bracken cover stratum or a combination of two strata, whereby all nine Red List species were primarily restricted to sparse or medium bracken cover. However, some generalist species were found to favor denser bracken stands, such as Tettigonia viridissima, contributing to the local Orthoptera beta diversity. Our data suggest that ongoing rotational sheep grazing with temporary paddocks is regarded as the most preferable management system. However, selected parts of the study area, which have only sparse vegetation and no pressure of bracken or scrub overgrowth, are recommended to be alternately left ungrazed for a few years to allow for the coexistence of different successional stages. Low-intensity bracken control measures, situationally by mowing or uprooting, are considered appropriate and should be pursued.Implications for insect conservationEven though most specialized and rare Orthoptera species in Western Europe tend to prefer sparsely vegetated areas, subareas with medium to even dense vegetation cover might promote certain generalist species, leading to a higher local species richness.

First record of Tettigonia viridissima Linnaeus, 1758 (Orthoptera: Tettigoniidae) as host of the ormiine Therobia leonidei Mesnil, 1964 (Diptera: Tachinidae)

The first record of the bush-cricket Tettigonia viridissima Linnaeus, 1758 (Orthoptera: Tettigoniidae) as host of the tachinid Therobia leonidei Mesnil, 1964 (Diptera: Tachinidae) is reported, and the unusual case of the parasitization of a female host is briefly discussed.

The species composition of the harmful entomofauna of soybean crops in the conditions of rice paddies

Goal. To determine the species composition of soybean phytophages under rice checks.
 Methods. The main field method with related phenological observations and analyzes. The study of the species composition of soybean pests was carried out in rice paddies of the Institute of Rice of the NAAS by collecting all objects with their subsequent identification. The survey was carried out once every 3—7 days: the first counts were in the third decade of May, when the plants were in the germination phase. Recorded plants were placed diagonally. On the experimental site, five plants were examined in 20 places.
 Results. Studies have been carried out to clarify the species composition of harmful entomofauna in soybean crops under the conditions of rice checks in the Southern Steppe of Ukraine. Found 20 species of phytophagus from 7 rows and 11 families and one species of spider mite: мeadow moth (Margaritia sticticalis L.); thistle, or vanessa thistle (Vanessa cardui L.); grass bug (Lygus rugulipennis Popp.); alfalfa bug (Carpocoris fuscispinus Boh.); alfalfa stink bug (Piezodorus lituratus F.); tobacco thrips (Thrips tabaci Lind.); scoop-gamma (Autographa gamma L.); alfalfa moth (Chloridea viriplaca Hfn.); green horse (Tettigonia viridissima L.); Italian Prussian (Calliptamus italicus L.); large cereal aphid (Sitobion avenae F.); Moroccan locust (Dociostaurus maroccanus Thunb.); six-point leafhopper (Macrosteles laevis Kib.); striped leafhopper (Psammotettix striatus L.); nosy tree (Aelia rostrata Bsh.); striped nodule weevil (Sitona lineatus L.); gray bristly weevil (Sitona crinitus Hfn.); cotton scoop (Helicoverpa armigera Hfn.); acacia moth (Etiella zinckenella Tr.), two-spotted spider mite (Tetranychus urticae Koch.).
 Conclusions. As a result of research in the conditions of the Southern Steppe of Ukraine, 20 species of phytophagous insects from 7 rows, 11 families and one species of tick were found in soybeans. The vast majority of pests in terms of numbers are among the Lepidoptera — 38%. These species damaged soybeans during the growing season and influenced the formation of the yield.

Sexual selection on bushcricket genitalia operates in a mosaic pattern.

In most species with internal fertilization, male genitalia evolve faster than other morphological structures. This holds true for genital titillators, which are used exclusively during mating in several bushcricket subfamilies. Several theories have been proposed for the sexual selection forces driving the evolution of internal genitalia, especially sperm competition, sexually antagonistic coevolution (SAC), and cryptic female choice (CFC). However, it is unclear whether the evolution of genitalia can be described with a single hypothesis or a combination of them. The study of species‐specific genitalia action could contribute to the controversial debate about the underlying selective evolutionary forces.We studied female mating behaviors in response to experimentally modified titillators in a phylogenetically nested set of four bushcricket species: Roeseliana roeselii, Pholidoptera littoralis littoralis, Tettigonia viridissima (of the subfamily Tettigoniinae), and Letana inflata (Phaneropterinae). Bushcricket titillators have several potential functions; they stimulate females and suppress female resistance, ensure proper ampulla or spermatophore attachment, and facilitate male fixation. In R. roeselii, titillators stimulate females to accept copulations, supporting sexual selection by CFC. Conversely, titillator modification had no observable effect on the female's behavior in T. viridissima. The titillators of Ph. l. littoralis mechanically support the mating position and the spermatophore transfer, pointing to sexual selection by SAC. Mixed support was found in L. inflata, where manipulation resulted in increased female resistance (evidence for CFC) and mating failures by reduced spermatophore transfer success (evidence for SAC). Sexual selection is highly species‐specific with a mosaic support for either cryptic female choice or sexually antagonistic coevolution or a combination of both in the four species.

Use of insecticides and other capturing techniques of bush cricket (Tettigonia viridissima): dietary implications among population of Tubah, Cameroon

Worldwide consumption of insects is today regarded as a good source of protein supplementation. This study aims at exploring the dietary factors, cooking, preservation techniques, and harvesting methods of longhorn grasshoppers ( Tettigonia viridissima ). The survey was conducted from September 2016 to January 2017 in Tubah council (North-West Region, Cameroon) using a semi-structured questionnaire, which was administered to two hundred T. viridissima harvesters. Chi-square was used to compare variables in a particular group for related measured factors. The main objective of the questionnaire was to find out how longhorn grasshoppers were harvested and consumed in the community. The harvesting of grasshoppers included three major techniques: hand picking (53%), trapping (29%) and use of insecticides (18%). Insecticides used (cypermethrin and deltamethrin) are from class II chemical toxicity. Dietary factors focused on: cooking methods (frying, roasting and boiling) and methods of preservation (sun drying and refrigerating). For the local population, grasshoppers constitute a good source of proteins from the month of September to January, but its safety is a concern as far as insecticides are used in harvesting them. Therefore, the population should be educated on the health risks linked to this malpractice method and the local and national authorities informed.

К ФАУНЕ КУЗНЕЧИКОВЫХ (ORTHOPTERA, TETTIGONIIDAE) ПСКОВСКОЙ ОБЛАСТИ

The paper focuses on several species of bush-crickets (Orthoptera, Tettigoniidae) which had not been recorded in central, southern and western parts of the Pskov region, north-western Russia, and were found there for the first time in 2017 and 2018. The bicoloured bush-cricket Bicolorana bicolor (Philippi, 1830) was collected in Sebezhsky district; the sickle-bearing bushcricket Phaneroptera falcata (Poda, 1761) was recorded in Nevelsky district; the great green bush-cricket Tettigonia viridissima L. was recorded in Pushkinogorsky district; the dark bush-cricket Pholidoptera griseoaptera (De Geer, 1773) was recorded in Pechorsky district.

Diet composition of syntopically breeding falcon species Falco vespertinus and Falco tinnunculus in south-western Slovakia

Abstract The red-footed falcon and Eurasian falcon represent two syntopical falcon species. While the Eurasian falcon is considered a common and numerous species in Slovakia, the red-footed falcon population has undergone a considerable decline during the past few decades. Nowadays it nests in a single locality in Slovakia, the Sysľovské polia Special Protection Area, which forms the northern and fragmented border of the species distribution area in Europe. By analysing prey remains from 9 nests (from 1998, 2001, 2013, 2014 and 2016), we identified 433 prey items belonging to 35 taxa and 9 orders. Every year, invertebrates made up the major part of the diet spectrum, in which Calosoma auropunctatum, Tettigonia viridissima, Zabrus tenebrioides, Anisoplia aegetum and Rhizotrogus sp. were the most frequent species of prey. Of the vertebrates, Microtus arvalis was the most hunted prey species. By supplementary analysis of 21 photos, we extended our knowledge on the diet by other 6 taxa. The peak of the M. arvalis population growth in 2014 did not manifest itself in the red-footed falcon diet composition. In 1998, 2014 and 2016 we also studied the diet of a syntopical species, the Eurasian kestrel. By analysing prey remains in 22 nests, we identified 1,151 prey items belonging to 37 taxa and 7 orders. In 1998 and 2014 vertebrates predominated, especially the common vole, however in 2016 invertebrates prevailed. This fact could be a reaction to the M. arvalis population peak in 2014 and its decline in 2016. These results suggest that this variability in the foraging behaviour of the Eurasian kestrel, an opportunistic predator, during the hunting of invertebrates increases the diet similarity and overlapping of the food niche of both studied falcon species.

First report of the genus Tettigonia Linnaeus (Orthoptera: Tettigoniidae: Tettigoniinae) and record of Tettigonia caudata caudata (Charpentier, 1842) from India.

The genus Tettigonia Linnaeus (Tettigoniidae; Tettigoniinae) with the type species, Gryllus (Tettigonia) viridissima Linnaeus, 1758 belongs to the tribe Tettigoniini, which is represented by 15 genera and 27 species worldwide (Cigliano et al., 2017). According to the annotated checklist, the subfamily Tettigoniinae includes the only tribe Platycleidini Brunner von Wattenwyl, 1893 with 2 genera and 3 species as reported from India by Shishodia et al. (2010). In a review of Orthoptera from the Eastern Palearctic region, the genus Tettigonia Linnaeus was reported by Storozhenko (1994); additionally, some new species of Tettigonia have been described by Ogawa (2003), Greenwalt and Rust (2014), Chobanov et al. (2014), Sultan et al. (2015) and Storozhenko et al. (2015). The sub-family Tettigoniinae is represented by many species endemic to the Asian part of the Palearctic region. In 1971, Kaltenbach studied the Decticinae of the Palearctic, a subfamily now considered part of Tettigoniinae, comprising 65 genera with 407 species; later, Rentz and Colless (1990) estimated 500 species for Tettigoniinae. Further, Rentz (1985) clarified that these species do not occur in tropical rainforests, but are found in grassland and mixed heath habitats. The shape of pronotum, with a distinct angulated shoulder incision, with the clarities and locations of its transversal sulci, and its short, compressed and depressed structure happens to be a common character for the members of the tribe Tettigoniini. The type genus Tettigonia is long winged; however, considerable variability in the wing length has been reported. Nevertheless, the short tegmina reaching to the end of hind knee is a character often used to separate T. caudata and T. viridissima from T. cantans and T. hispina (Haz, 1969).

Effect of Conidiobolus coronatus on the Cuticular and Internal Lipid Composition of Tettigonia viridissima Males.

Conidiobolus coronatus is an entomopathogenic fungus which has a potential as a biological control agent of insects. The cuticular and internal lipid composition of infected and noninfected Tettigonia viridissima males were analyzed by GC/MS. A total of 49 compounds were identified in the infected and noninfected males, including fatty acids, fatty acid methyl esters (FAMEs), n-alkanes, alcohols, sterols, and other organic compounds. The most abundant components of the cuticular and internal lipids of the insects were fatty acids. After exposure to C. coronatus, the cuticular lipids of the T. viridissima males contained 17 free fatty acids from C(8) to C(22), while the cuticular lipids of the noninfected insects contained only 15 fatty acids from C(12) to C(24). The cuticular and internal lipids of both the infected and the noninfected males also contained five FAMEs from C(15) to C(19), seven n-alkanes from C(25) to C(34), five alcohols from C(16) to C(25), five sterols, and the following six other organic compounds: azelaic acid, phenylacetic acid, glutaric acid, benzoic acid, sebacic acid, and glycerol. The compounds which were present only in the cuticular lipids of the infected males could be due to fungal infection.

Large-scale semi-automated acoustic monitoring allows to detect temporal decline of bush-crickets

Monitoring biodiversity over large spatial and temporal scales is crucial to assess the impact of global changes and environmental mitigation measures. However, large-scale monitoring of invertebrates remains poorly developed despite the importance of these organisms in ecosystem functioning. The development of new recording techniques and new methods of automatic species recognition based on sound detection and easily applicable within a citizen-science framework, offers interesting possibilities. However, the value of such protocols has not been tested for the study of temporal trends on a large spatial scale.We used an acoustic region-wide citizen-monitoring program of Orthoptera, conducted along roads, to assess the relevance of automatic species recognition methods to detect temporal trends while taking into account spatial and seasonal patterns of two Orthoptera species activity (Tettigonia viridissima Linnaeus, 1758, and Ruspolia nitidula Scopoli, 1786) at a large scale. Additionally, we tested the effect of climate and land-use variables on spatio-temporal abundance patterns using generalized linear mixed models. We found negative temporal trends for the two species across the survey period (2006–2012). The spatial variations were largely explained by the geoclimatic conditions and, to a lesser extent, by land use (negative effects of urbanization). The temporal variations were highly correlated to the climatic conditions of the year, and of the previous year (nonlinear effect of temperature, precipitation).To our knowledge, this paper describes the first successful attempt to calculate large-scale temporal trends of insect populations on the basis of an automatic identification process of acoustic data. We argue that acoustic monitoring along roads, coupled with the automatic recognition of species sounds, offers several advantages for assessing Orthoptera biodiversity response to global changes and environmental measures.

Two functional types of attachment pads on a single foot in the Namibia bush cricket Acanthoproctus diadematus (Orthoptera: Tettigoniidae).

Insects have developed different structures to adhere to surfaces. Most common are smooth and hairy attachment pads, while nubby pads have also been described for representatives of Mantophasmatodea, Phasmida and Plecoptera. Here we report on the unusual combination of nubby and smooth tarsal attachment structures in the !nara cricket Acanthoproctus diadematus. Their three proximal tarsal pads (euplantulae) have a nubby surface, whereas the most distal euplantula is rather smooth with a hexagonal ground pattern resembling that described for the great green bush-cricket Tettigonia viridissima. This is, to our knowledge, the first report on nubby euplantulae in Orthoptera and the co-occurrence of nubby and smooth euplantulae on a single tarsus in a polyneopteran species. When adhering upside down to a horizontal glass plate, A. diadematus attaches its nubby euplantulae less often, compared to situations in which the animal is hanging upright or head down on a vertical plate. We discuss possible reasons for this kind of clinging behaviour, such as morphological constrains, the different role of normal and shear forces in attachment enhancement of the nubby and smooth pads, ease of the detachment process, and adaptations to walking on cylindrical substrates.

Orthopteran insects as potential and preferred preys of the Red-footed Falcon (Falco vespertinus) in Hungary

Abstract Orthopterans play an important role in Red-footed Falcon diet, however, most studies focus only on its qualitative food composition, and less on quantitative composition and preferences of the taxa identified as prey. During the present research, an extensive orthopterological investigation was carried out in the Red-footed Falcon study area, Vásárhelyi Plain (SE-Hungary) between 2006 and 2008. Grasshoppers were sampled in their main habitats by sweep netting and pitfall trapping, and orthopterans were identified in the food remnants collected from the nests, both artificial and natural ones. 26 species were detected during the field works, 18 species from the food remnants. Altogether 32 species were identified. Prey preference values for all species for each year were calculated. More than two thirds of the identified preys were Decticus verrucivorus, and nearly 20% were Tettigonia viridissima. Other common prey species were Melanogryllus desertus, Platycleis affinis, Gryllotalpa gryllotalpa, Calliptamus italicus and Gryllus campestris. Based on the prey preference analysis, the most preferred species was Decticus verrucivorus with extreme high values, and the other preferred ones, overlapping with the previous list, were Platycleis affinis, Bicolorana bicolor, Tettigonia viridissima, Calliptamus italicus and Roeseliana roeselii. These results may help in the development of Red-footed Falcon-friendly habitats through the application of habitat management favourable for the preferred prey species.

Biogeographical patterns of variation in Western European populations of the great green bush-cricket (Tettigonia viridissima; Orthoptera Tettigoniidae)

The great green bush-cricket, Tettigonia viridissima, is at the northern limits of its geographic distribution in the UK and has suffered a significant reduction in population abundance and range over the last 50 years, now being largely confined to the southern UK. This study uses five characters to investigate differences between UK and mainland Western European populations, questioning the possibility that UK populations might represent a distinct species or sub-species and thus deserve special conservation status. Males of T. viridissima from UK, France and Spain were compared using morphometry, flight, male calling song and analysis of mitochondrial DNA sequences. Results suggest morphological differences between UK population samples and continental Europe with the UK samples showing shorter wing length relative to body length than populations in continental Europe. Morphological differences between French and Spanish populations followed a size cline related to latitude with more southerly populations showing larger features. Analysis of male flight distances and calling song showed significant differences with increased flight distance and minimum stridulation following a southerly latitude which correlates with wing length results. No differences consistent with geographical distributions were found in mitochondrial DNA COI sequence alignments. Morphological differences could be due to developmental differences linked to differing temperature clines or a non-adaptive difference caused by the colonisation history of the species. The consequences of morphometric variation on flight function and stridulation in bush-crickets are discussed.

Diet composition of the scops owl (Otus scops) in central Romania

Abstract Insect diversity correlates negatively with increasing management intensity of grasslands and with latitude. We supposed that similar patterns might be found in the diet spectra of insectivorous birds. The diet composition of the insectivorous scops owl was studied by analysing the prey remnants collected from 21 nests during 2008-2009 in an extensively cultivated rural area in the centre of the owl’s distribution range in Central Romania. Altogether 831 prey items belonging to 45 prey taxa were identified. Similarly to the other parts of the scops owl range, orthopterans were high dominant prey items (86.8%) - especially bush-crickets Tettigoniidae (78.6%). In food samles were found also beetles (Coleoptera, 5.7%) and rarely spiders Araneidea, moths Lepidoptera, mantids Mantodea, Hymenoptera and Neuroptera (<1 .5%). Vertebrates were rarely represented by rodents (2.5%) and passerines (1 .3%). The following diagnostic prey species were identified in 20 nests using the MDFM method: bush-crickets Tettigonia viridissima, Decticus verrucivorus, Metrioptera bicolor and other species of the family Tettigoniidae, the beetle Onthophagus spp., the cricket Gryllus campestris and other unidentified beetles Coleoptera g. sp. Furthermore, the scops owl’s diet in different parts of its range was compared. As expected, there were more Orthoptera and generally more prey taxa in food in the range centre than at its northern limit.

Impact of natural enemies on Obolodiplosis robiniae invasion

The gall midge Obolodiplosis robiniae is a pest of black locust Robinia pseudoacacia. The species was recently introduced into Europe and it is nowadays a usual insect in Slovakia, where two-year field surveys were undertaken during 2007–2008. The main objective of this study was to determine the natural enemies attacking O. robiniae and estimate their influence on midge population, less than 3 years after its introduction. Eight parasitoids and bushcricket Tettigonia viridissima were responsible for midge regulation. The parasitoid complex was not typically that of an introduced species as it was predicted. Firstly, the midge was heavily influenced by a specialized parasitoid Platygaster robiniae, which was a predominant parasitoid and accounted for 98% of all specimens reared. Secondly, annual larval parasitism varied from 5.4 to 10.8%, though the late season average parasitism achieved 26.0% and often exceeded 40%. P. robiniae was also very efficient in exploiting galls and was capable of consistently regulating midge population. The surveys demonstrated that the average cumulative impact of natural enemies on the midge was substantial. Stably around 20% of attacked galls were recorded during the late summer. Bushcrickets were as efficient as parasitoids and played an important role at control, especially during lack of parasitoids. Greater impact of parasitoids was found in the larger settlements than it was in the countryside, when countertendency was valid for bushcrickets. There is an indication that O. robiniae parasitized by specialized parasitoid, and attacked by bushcrickets represents only a moderate risk for R. pseudoacacia or forest stands.

Regeneration in the auditory system of nymphal and adult bush crickets Tettigonia viridissima

Regeneration and reestablishment of synaptic connections is an important topic in neurobiological research. In the present study, the regeneration of auditory afferents and the accompanying effects in the central nervous system are investigated in nymphs and adults of the bush cricket Tettigonia viridissima L. (Orthoptera: Tettigoniidae). In all animals in which the tympanal nerve is crushed, neuronal tracing shows a regrowth of the afferents into the prothoracic ganglion. This regeneration is seen in both adult and nymphal stages and starts 10–15 days after nerve crushing. Physiological recordings from the leg nerve indicate a recovery of tympanal fibres and a formation of functional connections to interneurones in the same time range. Electrophysiological recordings from the neck connective suggest additional contralateral sprouting of interneurones and the formation of aberrant connections. The regeneration processes of the tympanal nerve in nymphal stages and adults appear to be similar.