Fulltext search in archive



« advanced mode »

 previous    1   2   3   4   5   6  7   8   9   10   11   ...    next 

Results 151 to 180 of 1601:

Gastrophysa viridula (Coleoptera: Chrysomelidae) in the Czech Republic: Decline in a once abundant invasive oligophagous consumer of RumexOriginal article

Zdenka MARTINKOVA, Alois HONEK, Pavel SASKA

Eur. J. Entomol. 118: 250-254, 2021 | DOI: 10.14411/eje.2021.026

While the progress of the spread of invasive species of insects in new geographical areas are usually intensively monitored, the decline of these species often escape attention and is poorly documented. In this study, we record the decline in abundance of Gastrophysa viridula (DeGeer), an invasive oligophagous consumer of dock (Rumex spp.). This species originally inhabited Alpine regions. In the late 1800s, G. viridula was recorded in montane areas in the Czech Republic and then throughout this country. Gastrophysa viridula was very abundant in 1995-1999, when we found it in all of the 177 stands of R. obtusifolius inspected in western Czech Republic. In a repeated study of its occurrence in the same area from 2019-2020, this species was present in < 30% of 434 of the stands inspected and was only abundant (≥ 55% of plants in the stand infested by G. viridula) in < 4% of these stands. Thus the local occurrence and abundance of G. viridula had decreased significantly. Of the possible reasons for this decline the most probable are the effect of climate warming on host plant seasonality, changes in agricultural use of grasslands and fragmentation of large stands of dock.

Presence after three decades of red wood ants (Formica rufa group; Hymenoptera: Formicidae) in forests in an agricultural landscapeOriginal article

Harry J.M. VAN BUGGENUM

Eur. J. Entomol. 119: 85-91, 2022 | DOI: 10.14411/eje.2022.009

Conducting a repeat study of the presence of mound-building red wood ants (Formica rufa group) after a period of 30 years has rarely been done in Europe. From 1990 to 2020 such a study was done in an intensively used agricultural landscape with fragments of forest in the South-Eastern part of The Netherlands. In 1990, 280 nest mounds of three species of red wood ants and a hybrid were found in the forests and along forest edges. The highest occupancy was in forests of > 25 ha. The connectivity between the forest fragments mainly determined their presence. In 2020, only 160 nest mounds were found. The development of the colonies differed for Formica polyctena Förster, 1850 (slight decrease), F. rufa Linnaeus, 1761 (substantial increase) and F. pratensis Retzius, 1783 (strong decrease). The differences between the species in this highly fragmented landscape may be due to differences in their colonization strategies of either nest splitting or producing swarms of young queens. Furthermore, the analyses show that the type of environment (in a forest or along a forest edge) determines the probability of extinction or settlement. There is a need to undertake management measures to prevent the extinction of species of red wood ants in the area studied. These measures include creating small clearings in dense forests, reducing shading due to overgrowing shrubs or herbaceous plants, and creating buffer zones around intensively manured fields. More long-term monitoring is needed in Europe to compare the circumstances in different regions, detect trends and evaluate the effects of protection measures.

First fossil representative of the tribe Amphignomini (Hemiptera: Fulgoromorpha: Achilidae) from mid-Cretaceous Kachin amber and its significanceOriginal article

Alicja Magdalena BRYSZ, Patrick MÜLLER, Jacek SZWEDO

Eur. J. Entomol. 120: 42-49, 2023 | DOI: 10.14411/eje.2023.006

A new genus Amphignokachinia Brysz & Szwedo, gen. n. and species Amphignokachinia subversa Brysz & Szwedo, sp. n. of Achilidae (Hemiptera) planthoppers of the tribe Amphignomini are described. It is the second genus and first fossil representative of the tribe Amphignomini coming from the Cenomanian amber in Kachin State, Myanmar. Diagnosis of the tribe is revised and its position in respect of fossils in the family Achilidae is discussed.

The proteins involved in larval colouration in the cuticle and haemolymph of two strains of Antheraea pernyi (Lepidoptera: Saturniidae)Short Communication

Guobao WANG, Jiangrun WANG, Lei NIE

Eur. J. Entomol. 120: 310-315, 2023 | DOI: 10.14411/eje.2023.032

The proteome profiles of the cuticle and haemolymph of two strains of the Chinese Oak silk moth A. pernyi, with cyan and yellow coloured bodies, were compared in order to identify the differentially expressed proteins (DEPs) that determine the differences in the colouration of the two strains. A total of 324 DEPs, including 124 up-regulated and 200 down-regulated proteins, were identified in the cuticles of the cyan and yellow coloured individuals, and 286 DEPs including 79 up-regulated and 207 down-regulated proteins in the haemolymph of the cyan and yellow coloured individuals. Several DEPs associated with the colour of larvae of A. pernyi were screened, including an ommochrome-binding protein, juvenile hormone esterase, protein yellow, L-dopachrome tautomerase yellow-f2 and fumarylacetoacetase, the expression levels in the cuticle and haemolymph of the yellow larvae were higher than those in the cyan coloured larvae, indicating their possible roles underlying the colouration of the yellow larvae of A. pernyi.

Feeding habits of the endangered Japanese diving beetle Hydaticus bowringii (Coleoptera: Dytiscidae) larvae in paddy fields and implications for its conservationOriginal article

Reiya WATANABE, Shin-Ya OHBA, Tomoyuki YOKOI

Eur. J. Entomol. 117: 430-441, 2020 | DOI: 10.14411/eje.2020.047

The diving beetle Hydaticus bowringii Clark, 1864 (Coleoptera: Dytiscidae) is on the Red List of Japan as 'Near Threatened'. However, there is no quantitative information on the feeding habits of its larvae, which could be used to aid its conservation. In order to determine the prey that are important for the survival and growth of larvae of H. bowringii, we combined the results of field surveys of paddy fields and rearing experiments. In the field, H. bowringii larvae predominantly feed on tadpoles of five species of frogs and occasionally also on insects, loaches and worms. The phenology of the tadpoles was similar to that of larvae of H. bowringii, as their abundances increased from May to June and decreased in July. Experimentally reared larvae of H. bowringii grew faster when fed tadpoles than when fed Sigara nymphs or a mixture of both prey, and more emerged as adults when tadpoles were included in their diet. Adults were larger in the tadpole treatment than in the Sigara treatment. Based on these results, we conclude that tadpoles are more suitable prey for the survival and growth of larvae of H. bowringii than insects. The decline in the abundance of frogs could be one of the factors determining the decrease in the local abundances of H. bowringii. In conclusion, we affirm that in order to conserve populations of H. bowringii it is crucial to maintain paddy field environments in which frogs are abundant.

The effect of temperature and photoperiod on the time taken for a meal to pass through the gut, defecation and digestion in the last larval instar of Spodoptera littoralis (Lepidoptera: Noctuidae)Original article

Esmat HEGAZI, Wedad KHAFAGI, Essam AGAMY, Ibrahim ABDALLAH

Eur. J. Entomol. 119: 398-404, 2022 | DOI: 10.14411/eje.2022.041

Spodoptera littoralis (Boisduval) is a highly destructive and polyphagous insect pest of great economic importance. It develops throughout the year and the larvae are non-diapausing. Little work has been done on the time taken for food to pass through the gut of S. littoralis. Thus, this study on starving and well fed last instar larvae of S. littoralis aimed to determine the effect of temperature and photoperiod on the time taken for a meal to pass through the gut, defecation and digestion. The results indicate that it depended on temperature, photoperiod and hunger. The time that elapsed between a larva being fed and the production of the first faecal pellet, which is a measure of the time it takes for food pass to pass through the gut (SFP), differed significantly at different temperatures and photoperiods. The SFP was longer at 15°C than at 30°C. At 20°C and under a short photoperiod, SFP was very much shorter than under a long photoperiod (18L : 6D). In addition, at 20°C, the time to defecation was significantly longer under a photoperiod of 12L : 12D than under continuous light. In all the tests > 95% of the larvae produced four faecal pellets per meal. The digestibility values varied significantly in the different tests. This study offers new insights into the passage of food from the crop to the rectum at different temperatures and photoperiods. This might help in understanding the adaptability of S. littoralis and may also help in controlling this important pest.

A dichotomous key and checklist for Mexican Athysanini leafhopper genera (Hemiptera: Cicadellidae) with a new species from the Oaxacan dry tropical forestOriginal article

J. Adilson PINEDO-ESCATEL, Christopher H. DIETRICH, James N. ZAHNISER, Gustavo MOYA-RAYGOZA, Liberato PORTILLO

Eur. J. Entomol. 118: 255-278, 2021 | DOI: 10.14411/eje.2021.027

Most Neotropical forest-dwelling leafhopper species are rare and exhibit limited distributions. The Mexican leafhopper fauna is known to be highly diverse and identification of genera and species is difficult because no attempts have been made to provide comprehensive identification tools for the fauna. Here, a dichotomous key to all genera recognized within Mexico of the diverse but little studied leafhopper tribe Athysanini is provided. Spinulana josefinae Pinedo-Escatel sp. n. is described and illustrated based on specimens collected in the dry tropical forest of Oaxacan mountains. A total of 46 genera and 146 species are now recognized in the checklist of Athysanini of Mexico. Notes on type repositories, distributional data and maps, and selected references are provided.

The northward spread of the European mantis, Mantis religiosa (Mantodea: Mantidae): Data from LithuaniaOriginal article

Jolanta RIMŠAITĖ, Povilas IVINSKIS, Galina BARTKEVIČIENĖ, Rasa BERNOTIENĖ

Eur. J. Entomol. 119: 318-326, 2022 | DOI: 10.14411/eje.2022.033

Geographic distribution of the European mantis, Mantis religiosa (Linnaeus, 1758) in Europe covers mostly southern and central Europe, but this species has recently shown a significant northward spread. First reports of M. religiosa in Lithuania were in 2008 and now these insects are distributed throughout this country. Information on the spread of M. religiosa in Lithuania between 2015 and 2020 are analysed in this paper. The spread of this insect in Lithuania and neighbouring countries can be related to changes in climate, in particular, the increase in average annual temperature and milder winters. Possible routes along which M. religiosa spread northwards based on an analysis of mtDNA sequences are presented.

Perennial alternative crops for biogas production increase arthropod abundance and diversity after harvest - results of suction sampling and metabarcodingOriginal article

Johannes BURMEISTER, Bernd PANASSITI, Franziska HEINE, Sebastian WOLFRUM, Jerome MORINIERE

Eur. J. Entomol. 120: 59-69, 2023 | DOI: 10.14411/eje.2023.009

The effects of novel perennial energy crops on arthropod abundance and diversity were tested using three field trials in Bavaria. Established cup plant (Silphium perfoliatum), Virginia mallow (Sida hermaphrodita) and tall wheat grass (Thinopyrum ponticum) plots were sampled in autumn using a modified leaf blower and their arthropod faunas compared with that recorded in maize plots. At the time of sampling, maize, cup plant and Virginia mallow had already been harvested and samples from the remaining stubble were compared with those from open ground. Collembola were the most abundant group. The highest abundance and diversity of arthropods was recorded in tall wheat grass, with Hemiptera and Aranea especially benefitting from the green and taller vegetation. Post-harvest cup plant and Virginia mallow plots harboured a more diverse and more abundant arthropod assemblage than maize plots. Stubble was identified as a suitable habitat for arthropods in agricultural fields. In conclusion, the integration of perennial energy crops into existing biogas production systems could play an important role in supporting arthropods in agricultural landscapes by providing crucial structures and resources, such as the grassy vegetation of tall wheat grass in autumn and the long-lasting stubbles of cup plant and Virginia mallow.

Comparative micro-computed tomographic analysis of the structure of brood cells and its effect on the development of the pupae of honey bee (Apis mellifera)Original article

Tamás SIPOS, Tamás DONKÓ, Ádám CSÓKA, Tamás KISS, Sándor KESZTHELYI

Eur. J. Entomol. 120: 9-14, 2023 | DOI: 10.14411/eje.2023.002

Most beekeepers worldwide use the same combs in their hives for many years, which can result in alterations in the inner volume of the comb cells. The objective of this survey using microcomputed tomography was to reveal developmental disorders caused by this beekeeping practice. The extent of the thickening of the wall of brood cells that occurs as a result of the long-term use of the combs was determined. This alteration resulted in a reduction in the inner volume of the comb cells, which had a significant effect on the size of the pupae and possibly the health of the imagoes. The walls of the cells can be divided into two well-determined parts, which can be exactly visualized using micro-CT. In addition, the inner structure of the wall in the first part of the cell was altered by very radio dense remains of cocoons. The material in the other part of the cell is less radio dense and as previously suggested is mainly wax. The decrease in the length, surface and volume of these cells adversely affected the developing pupae, which according to previous studies results in a reduction in the production of workers, colony strength and honey yield. The extent of the reduction in the body regions of pupae was on average 4.98%. Overall, the volume of the pupae that developed in these narrow comb cells were smaller by an average of 12.22%.

Plant essential oils induce expression of heat shock proteins and antioxidant enzyme activity in carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae)Original article

Saeed FARAHANI, Ali R. BANDANI

Eur. J. Entomol. 120: 161-169, 2023 | DOI: 10.14411/eje.2023.021

Rising concerns about the negative effects of chemical compounds in pest control have made it increasingly necessary to find new environmentally friendly compounds to combat insect pests. In recent years, the use of plant derivatives, such as, essential oils have proved very promising. Despite the many studies on essential oils, there are very few studies on the effect of these oils on induction of Heat shock proteins (HSPs) and antioxidant enzymes. Therefore, it was hypothesized that the exposure of insects to essential oils induce stress, which it is likely induces the production of heat shock proteins and antioxidant enzymes. Thus, Ectomyelois ceratoniae Clark (Lepidoptera: Pyralidae) was used as a model insect to study the lethal and sublethal effect of the fumigant toxicity of the essential oils extracted from the plants Thymus daenensis Celak and Satureja khuzistanica Jamzad. Gas Chromatography/Mass Spectrometry indicated that thymol and carvacrol were the major component of T. daenensis and S. khuzistanica extracts, respectively. Exposing E. ceratoniae to sublethal doses of the essential oils (LC30) and using RT-qPCR indicated that the expression levels of HSP70 and HSP90 were significantly increased. Activities of antioxidant enzymes including SOD, CA, POX, GST and the concentration of MDA increased following exposure to sublethal doses of both essential oils. These findings clearly show that in addition to the reported effects of essential oils, oxidative stress and induction of free radical production could be another mode of the action of essential oils on insects.

A revision of the Neotropical genus Chespiritos (Diptera: Sphaeroceridae: Limosininae)Original article

Gregory K. KUWAHARA, Stephen A. MARSHALL

Eur. J. Entomol. 117: 164-189, 2020 | DOI: 10.14411/eje.2020.019

The genus Chespiritos Marshall, 2000 (Diptera: Sphaeroceridae) is revised, including C. sindecimus Marshall, 2000, C. pervadens Roháček and Buck, 2003 and 19 new species. The following new species are described, keyed and placed in a morphological phylogeny: C. anguineus sp. n. from Bolivia, C. attenboroughi sp. n. from Argentina, C. balrogiformis sp. n. from Peru, C. bolanosi sp. n. from Mexico, C. calceus sp. n. from Peru, C. chicobrazos sp. n. from Costa Rica, C. coronatus sp. n. from Bolivia, Brazil, Colombia, Costa Rica, Ecuador and Trinidad, C. dolabratus sp. n. from Costa Rica, C. elephantus sp. n. from Ecuador and Peru, C. extendido sp. n. from Bolivia, Colombia, Costa Rica, Ecuador, Mexico, Panama and Venezuela, C. ganchopico sp. n. from Argentina, Bolivia, Ecuador, Panama and Tobago, C. gladiator sp. n. from Costa Rica, C. hojagrande sp. n. from Costa Rica and Mexico, C. jamaicensis sp. n. from Jamaica, C. lepustergum sp. n. from Costa Rica and Venezuela, C. metroidiformis sp. n. from Costa Rica, C. paraiso sp. n. from Dominican Republic, C. peckorum sp. n. from Ecuador, and C. ventrisetis sp. n. from Brazil, Costa Rica and Venezuela.

Insect photoperiodism: Seasonal development on a revolving planetReview

David SAUNDERS

Eur. J. Entomol. 117: 328-342, 2020 | DOI: 10.14411/eje.2020.038

This review starts by comparing photoperiodic diapause with non-photoperiodic quiescence in four representative species, paying particular attention to overwintering in Drosophila melanogaster. In the second part it describes dormancy strategies of insects from the equator to the polar regions, addressing topics such as the role of the circadian system in photoperiodic time measurement, latitudinal clines in diapause-related traits, hourglass-like photoperiodic clocks based on dampening circadian oscillators, and the dormancy strategies of insects close to the equator or at high latitudes where seasonal changes in photoperiod are unreliable or absent.

Mitochondrial DNA variation of Drosophila obscura (Diptera: Drosophilidae) across EuropeOriginal article

Pavle ERIĆ, Marina STAMENKOVIĆ-RADAK, Milan DRAGIĆEVIĆ, Maaria KANKARE, Megan A. WALLACE, Marija SAVIĆ VESELINOVIĆ, Mihailo JELIĆ

Eur. J. Entomol. 119: 99-110, 2022 | DOI: 10.14411/eje.2022.011

Drosophila obscura is a common fruit fly that inhabits the temperate forests of Europe. While it is abundant in the north compared to other Drosophila, its density decreases southwards, where it is gradually replaced by other Drosophila species. This study describes variation in the mitochondrial Cyt b gene of D. obscura from several European populations. We observed a large number of haplotypes, together with the structuring of genetic variation. Genetic variation is higher in the west where O1 and related divergent haplotypes dominate. In the east, the O2 haplotype is most frequent, together with haplotypes that recently arose from it. In the central part of the species range, both O1 and O2 are equally present, along with many others. These data reveal signs of population expansions that probably happened earlier in the west, and more recently in the east. Though our conclusions are based on only one genetic marker, limiting the power of the analysis, the results imply either postglacial expansion from two unique sources or, more likely, eastwards stepping-stone expansion. This study adds important information on genetic variation and phylogeography to the obscure biology of D. obscura, a species that has the potential to become an interesting model in evolutionary biology and conservation genetics.

Do egg parasitoids increase the tendency of Lestes sponsa (Odonata: Lestidae) to oviposit underwater?

Filip HARABIŠ, Aleš DOLNÝ, Jana HELEBRANDOVÁ, Tereza RUSKOVÁ

Eur. J. Entomol. 112 (1): 63-68, 2015 | DOI: 10.14411/eje.2015.017

The selection of oviposition sites by insects can significantly affect egg mortality. Spreadwing damselflies (Odonata: Lestidae) predominantly lay their eggs in parts of plants growing above the surface of water and only occasionally also those parts growing underwater. Factors affecting the choice of oviposition site and decision to lay underwater are still poorly understood. We examined whether localities with different risk of egg parasitism, different oviposition strategies (above or below the water surface) and the depth at which the eggs were laid, affected the total number of eggs laid, the proportion parasitized and egg mortality. In general, a significantly higher proportion of the eggs laid above the surface of water were parasitized but spreadwing damselflies showed significant preference for laying eggs underwater at both of the sites studied. This preference, however, had a different effect on the overall mortality of eggs at the two sites studied. Hence underwater oviposition by damselflies may be seen as a conditional anti-predator strategy, occurring only if the benefits exceed potential risks. Underwater oviposition may provide additional benefits other than protection against egg parasitism.

Cold and freezing injury in insects: An overview of molecular mechanismsIvo Hodek special issueReview

Jan ROZSYPAL

Eur. J. Entomol. 119: 43-57, 2022 | DOI: 10.14411/eje.2022.005

The present review discusses the molecular mechanisms of injury caused by low temperatures and/or freezing. The review is intended mainly for insect environmental physiologists who focus on the effects of low temperatures. The review successively discusses (1) the effects of low temperatures on the structure and function of macromolecules; (2) the effects of freezing on cells and macromolecules and (3) the mechanisms of damage during thawing and post-thaw. The review shows that injury primarily occurs at the molecular level in terms of damage to proteins, nucleic acids and biological membranes. The damage to macromolecular structures occurs as a result of the interaction between the effects of temperature, ice formation and resulting secondary effects such as osmotic stress, increased concentration of solutes, cellular freeze dehydration, disruption of ionic balance and oxidative stress. The present review attempts to identify gaps in our knowledge on the mechanisms of cold injury in organisms and proposes possible future directions that could contribute to filling the gaps.

Barrier pitfall traps increase captures of ground beetles (Coleoptera: Carabidae) on exposed riverine sedimentsOriginal article

Scott HORN

Eur. J. Entomol. 117: 76-82, 2020 | DOI: 10.14411/eje.2020.008

Exposed riverine sediments are unique riparian environments that exhibit high biodiversity and harbor many specialist species. Ground beetles are the most well studied inhabitants within these environments where they are often sampled using pitfall traps. In order to develop conservation measures for species occupying these habitats a logical first step is to refine sampling methods so that proper biodiversity assessments can be carried out. To that end, the effectiveness of two pitfall trap designs (standard trap vs. barrier trap) was evaluated. Over three sampling periods we collected 5,186 individuals represented by 43 species. Barrier traps proved to be superior, yielding significantly greater numbers of individuals (n = 3,456 vs. 1,730) than standard traps. Additionally, we collected more ground beetle species (37 vs. 30) in barrier traps than in standard pitfall traps. This study supports the rationale for deployment of more than one trap design to avoid deficiencies exhibited by a single type.

Taxonomic revision of the highly threatened Eumerus tricolor species group (Diptera: Syrphidae) in Southeast Europe, with insights into the conservation of the genus EumerusOriginal article

Ana GRKOVIĆ, Jeroen VAN STEENIS, Marija MILIČIĆ, Nataša KOČIŠ TUBIĆ, Mihajla DJAN, Snežana RADENKOVIĆ, Ante VUJIĆ

Eur. J. Entomol. 118: 368-393, 2021 | DOI: 10.14411/eje.2021.039

The diversity in the Eumerus tricolor group, the largest group within the genus in Southeast Europe, is investigated. Two new, locally distributed species are described, E. crispus Vujić & Grković, sp. n. from Serbia and E. nigrorufus Grković & Vujić, sp. n. from Montenegro. In addition to Southeast European members, one related species E. arctus van Steenis, sp. n. is described from Switzerland. We designate lectotypes for E. ovatus Loew, 1848, E. tarsalis Loew, 1848, E. tricolor (Fabricius, 1798) and E. varius Meigen, 1822. A map of the distribution of members of the E. tricolor group in Southeast Europe is provided. In addition, records from other parts of Europe are listed and an illustrated identification key to the SE European species of the E. tricolor group provided. We also study and discuss the significance of small habitat patches for the preservation of species of Eumerus, because the three species described in this paper are currently known from such patches.

Classification and characterization of immune haemocytes in the larvae of the Indian fritillary, Papilio hyperbius (Lepidoptera: Nymphalidae)Original article

Min-Soo GO, Youngwoo CHO, Ki-Byung PARK, Mijeong KIM, Sung Su PARK, Jangwoo PARK, Saeyoull CHO

Eur. J. Entomol. 119: 430-438, 2022 | DOI: 10.14411/eje.2022.045

In this study, haemocytes present in Papilio hyperbius Linnaeus were identified and characterized. Six different types of haemocyte were recorded in the haemocoel of this species of insect: prohaemocytes, plasmatocytes, granulocytes, spherulocytes, adipohaemocytes and oenocytoids. Of these the granulocytes were found to be responsible for cell-mediated immune responses such as phagocytosis. Granulocytes that were exposed to immunity inducers (carboxylate-modified polystyrene latex beads [CLBs] and Escherichia coli) had fan-like or pod-like structures on their cell membranes. The lysosomes in granulocytes were activated 2 h after injection with E. coli and after 12 h, all granulocytes exhibited highly activated lysosomes. After 24 and 48 h, the lysosome activity in granulocytes decreased. Transmission electron microscopy revealed that phagocytosis, which was mediated by granulocytes in the early hours of the E. coli infection, led to the formation of one phagosome for one E. coli within the cytosol. Moreover, as time passed, endosomes or lysosomes of different size developed. Subsequently, the phagosomes and lysosomes fused and E. coli were eliminated. After this series of immune responses, the nuclei of the granulocytes were indistinct and their cellular activity decreased. Hence, as old immune cells were replaced by new ones, active and healthy immune haemocytes were presumed to be maintained in the hemocoel.

Feeding behavior and mobility of carabid beetles in response to perceived risk of predationCarabidological special issueOriginal article

Stefanie E. DE HEIJ, Khaldoun A. ALI, Sean M. PRAGER, Christian J. WILLENBORG

Eur. J. Entomol. 120: 81-92, 2023 | DOI: 10.14411/eje.2023.011

Carabid beetles are common inhabitants of agricultural fields where they encounter a variety of food options - including prey and weed seeds. The feeding behaviors of carabids are often influenced by the physical and chemical traits of prey and seed species, as such traits determine prey or seed species that are suitable for consumption. However, some carabid species may prey upon other carabids, complicating their role as beneficial insects due to consumptive (direct) and non-consumptive (indirect) intra-guild predation effects. The non-consumptive effects of intra-guild predation are expected to influence prey and seed foraging behaviors of carabids because those behaviors are likely to be adapted as a function of duration and intensity of predation risk. In this study, we wanted to explore the non-consumptive effects of the carabid intra-guild predator Pterosticus melanarius on mobility and feeding behavior of two carabid omnivores: Harpalus amputatus and Amara spp. Choice and no-choice feeding arenas coupled with a video system were used to study the responses of carabid beetles to the odor cues of P. melanarius. Odor cues left by P. melanarius caused H. amputatus to reduce its activity when canola seeds (Brassica napus) were offered in the feeding arenas. In contrast, P. melanarius cues did not cause H. amputatus to alter its mobility when freeze-killed fruit flies were offered in the feeding arenas, although this species did increase consumption of fruit flies under these cues. Amara spp. offered canola seeds increased their mobility and relative seed preferences when exposed to the odor cues of P. melanarius. Overall, our work shows carabid species do alter aspects of their foraging behavior under intra-guild predation risks, but this is unlikely to reduce their contributions to seed or prey biocontrol.

The effect of conductor wires of different metals on the amount of honey bee (Apis mellifera; Hymenoptera: Apidae) venom collected and its chemical contentOriginal article

Nazim TURAN, Cengiz ERKAN

Eur. J. Entomol. 120: 366-371, 2023 | DOI: 10.14411/eje.2023.040

Researchers have been interested in honey bee, Apis mellifera L., venom for many years, but the previous studies focused mainly on its pharmacological properties and the factors affecting its production and chemical content were less well evaluated. This research aims to investigate the potential effect of the method of collecting bee venom on its chemical content. To achieve this, brass, steel, aluminium and copper wire conductors were used. This research was carried out at Van YYU Beekeeping Application and Research Centre, where the venom was collected dry on glass plates from 16 Caucasian F1 honey bee colonies. The quantity produced and its composition in terms of melittin, apamin and phospholipase A2 were determined after storage. Duncan and LSD Multiple Comparison tests on the amounts of venom collected using aluminium, copper, steel and brass wires for conducting electricity, revealed it was 21.03 ± 3.50, 15.08 ± 0.32, 22.38 ± 6.35 and 30.35 ± 3.66 mg, respectively. Although these values differed significantly (p < 0.05), the chemical content of the bee venom was the same. The colour of the venom was associated with the material of the electrical conductor used. It was concluded that it would be beneficial to carry out further studies using more colonies along with using residue analysis.

Motorway as a barrier to dispersal of the threatened dragonfly Sympetrum depressiusculum (Odonata: Libellulidae): Consequence of mortality or crossing avoidance?Original article

Hana ŠIGUTOVÁ, Filip HARABIŠ, Michal HYKEL, Aleš DOLNÝ

Eur. J. Entomol. 114: 391-399, 2017 | DOI: 10.14411/eje.2017.050

Infrastructure is one of the main causes of landscape fragmentation, which results in isolation and loss of populations. Although the negative effect of roads on insects is well documented, only a minority of studies has focused on roads in the context of barriers to dispersal. Flying species in particular have been neglected. We investigated the effect of a four-lane motorway as a barrier to the movement of an isolated population of the threatened dragonfly Sympetrum depressiusculum in an agricultural landscape in Central Europe. Generalized additive models were used to assess the motorway's effect on (i) the distribution of adult dragonflies in patches of terrestrial habitat surrounding their natal site, and (ii) individual flight behaviour (i.e. willingness or unwillingness to cross the motorway). Movement patterns of marked adults throughout the landscape were also investigated. During one season, significantly fewer adults were found at patches located on the far side of the motorway, indicating it has a barrier effect. Observations on flight behaviour revealed no apparent effect of the motorway. The possible barrier effect for the species studied was therefore presumed to be a consequence of road mortality. Our results indicate that the motorway may influence the dispersal of this threatened species of dragonfly, which is a habitat specialist with particular requirements for its terrestrial environment. Negative effects on other species with similar behaviour and strategy can be presumed. When establishing new habitats, carrying out reintroductions or translocations, it is necessary to consider that roadways may reduce population size and affect population dynamics by limiting dispersal.

Daily survival and dispersal of adult Rhagonycha fulva (Coleoptera: Cantharidae) in a wooded agricultural landscapeOriginal article

Laura E. RODWELL, Jennifer J. DAY, Christopher W. FOSTER, Graham J. HOLLOWAY

Eur. J. Entomol. 115: 432-436, 2018 | DOI: 10.14411/eje.2018.043

Studies of insect population under field conditions to establish survival rates, longevity and dispersal rates are rare in the literature. These types of studies are important and can be used to inform studies of the effects of landscape composition and configuration on levels of biodiversity. Here the Cantharidae beetle, Rhagonycha fulva is studied under field conditions to derive estimates of daily survival rates for both males and females as well as local dispersal rates. Survival was studied at two sites, one in Wales and another in England, whilst dispersal was examined only at the Welsh site. Beetles were marked using different coloured enamel paints at the mid-point of a 200 m linear transect. The beetles were almost exclusively found (and marked) on common hogweed, Heracleum sphondylium. No difference in survival was found between males and females at both of the sites. The survival rates found at the two sites also did not differ. The overall daily survival rate was 0.771 equating with a median longevity of 4.37 days. Casual observations yielded a small number of marked individuals in excess of 400 m away from the point of marking. Movement of males along the transect differed from females. Marked females were never found far from the point of marking whilst males moved further away with time. This difference in behaviour is discussed in terms of hypothesized insect dispersal behaviour following emergence as mobile adults.

Distinct barcodes for the Cereal leaf beetles Oulema melanopus and Oulema duftschmidi (Coleoptera: Chrysomelidae), two syntopical sibling speciesOriginal article

Julie LEROY, Jean-David CHAPELIN-VISCARDI, Guénaëlle GENSON, Julien HARAN, Éric PIERRE, Jean-Claude STREITO

Eur. J. Entomol. 117: 490-503, 2020 | DOI: 10.14411/eje.2020.052

Oulema melanopus (Linnaeus, 1758) and Oulema duftschmidi (Redtenbacher, 1874) (Coleoptera: Chrysomelidae) are two native West Palaearctic species developing on various cultivated and wild grasses. Along with O. obscura they are considered to be secondary pests of cereal crops. However, local outbreaks have been recorded recently and their status as secondary pests may evolve, especially as the use of broad-spectrum insecticides is now greatly reduced. Oulema melanopus and O. duftschmidi are considered to be sibling species. They are morphologically very close and difficult to distinguish from each other, which makes it difficult to study them. We tested the reliability of the standard barcode fragment (COI) for distinguishing between these species. A total of 92 samples of the two species, covering the majority of their natural range, was sequenced for the barcode fragment and inter- and intraspecific genetic distances were estimated. Our results confirm those of Bezděk & Baselga (2015, Acta Entomol. Mus. Nat. Prag. 55: 273-304) in that this marker cannot differentiate between all the species of the Oulema melanopus complex, which in the Mediterranean basin contains several described and possibly some undescribed cryptic species. However, this marker may be useful in an agricultural context in areas where only O. melanopus and O. duftschmidi occur (such as in cereal crops in France) where it can be used to reliably and rapidly separate all stages of these two taxa and can therefore help in studying their ecology and dynamics.

Time measurement in insect photoperiodism: The role of photophase duration and light intensityIvo Hodek special issueReview

David SAUNDERS

Eur. J. Entomol. 119: 69-76, 2022 | DOI: 10.14411/eje.2022.007

The initial stages of diapause induction - as summer gives way to autumn - involve a process of time measurement in which the duration of daylength (or nightlength) is determined by a photoperiodic 'clock' based upon the circadian system. In many insects so far examined, a photophase of sufficient duration and illuminance resets a photoperiodic oscillator to a constant phase equivalent to the beginning of the 'subjective night' (Circadian time, CT 12 h) whereupon it proceeds to measure nightlength in a clock of the external coincidence type. A possible exception may be found in the linden bug, Pyrrhocoris apterus, which - in laboratory studies using relatively low light intensity - suggests that daylength is measured rather than the night. Earlier studies of photoperiodic responses (pupal diapause induction) in the flesh fly Sarcophaga argyrostoma, however, showed that 'weak' or short light pulses giving rise to Type 1 phase response curves could be converted by increasing light intensity to Type 0 responses that phase set the oscillation to the beginning of the subjective night (CT 12 h) whereupon it could begin to measure the night. Based upon these data it is therefore suggested that the photoperiodic clock in P. apterus might also measure nightlength if the bugs were exposed to photophases of higher irradiance simulating daytime exposure to the light intensity experienced by these diurnally active insects in their natural environment.

Habitat of Carabus zawadzkii (Coleoptera: Carabidae) in the Eastern CarpathiansOriginal article

Peter GAJDOŠ, Stanislav DAVID, Oto MAJZLAN, Tomáš JÁSZAY, Ján ČERNECKÝ

Eur. J. Entomol. 119: 285-299, 2022 | DOI: 10.14411/eje.2022.030

This paper provides an analysis of the rare and important Natura 2000 species Carabus zawadzkii in terms of its ecological niche, conservation status and relationship with other Carabus species in carabid assemblages. Published sources are inconsistent in defining the habitats in which this species occurs. Therefore, a large part of this paper is dedicated to identifying the relationship of Carabus zawadzkii with particular non-forest habitats based on field research conducted in 2011-2013. The results revealed an unexpected affinity of this species for non-forest habitats in addition to the know relationship with forest habitats. Further analysis, using additional field data collected over the period 2013-2021, also focused on the assessment of the current conservation status of this rare species. Overall, the population of this species seems stable; however, to improve its conservation status it requires particular management measures. Important conservation measures include periodic extensive mowing of mountain hay meadows. This species' seasonal dynamics provides important information for nature conservationists. It is important to carry out research on this species in May, when it is most active. Presented results provide the most comprehensive overview of the ecological preferences and occurrence of this important and very rare Carpathian species.

Inoculation of cucumber plants with Beauveria bassiana enhances resistance to Aphis gossypii (Hemiptera: Aphididae) and increases aphid susceptibility to pirimicarbOriginal article

Mohammad HOMAYOONZADEH, Mojtaba ESMAEILY, Khalil TALEBI, Hossein ALLAHYARI, Stuart REITZ, J.P. MICHAUD

Eur. J. Entomol. 119: 1-11, 2022 | DOI: 10.14411/eje.2022.001

The entomopathogen Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) can colonize plants endophytically and stimulate the production of secondary plant metabolites with anti-herbivore activities. We assayed the topical virulence of B. bassiana to Aphis gossypii Glover (Hemiptera: Aphididae), the effects of cucumber inoculation with this fungus on plant metabolites, and the physiological consequences for aphids that fed on these plants. Assays were conducted with both the commercial formulation of B. bassiana, 'Naturalis®-L', at the recommended concentration of 1.5 ml / L (yielding a spore concentration of 2.3 × 107 CFU per ml), and with a similar concentration of the isolated fungal strain. Topical application of 0.03 ml of solution per cm2, or 1 × 103 CFU, caused 100% mortality to A. gossypii adults after seven days, whether Naturalis®-L or the isolate alone was used. The fungus grew endophytically into foliage when sprayed on cucumbers at the 2-leaf stage and concentrations of alkaloids, flavonoids, phenols, hydrogen peroxide, and total chlorophyll were higher than in control plants 28 days after inoculation. Malondialdehyde content, plant growth, and total yield were unaffected by B. bassiana inoculation. Aphids fed on B. bassiana-inoculated plants for 24 h had reduced activities of detoxifying enzymes (glutathione-S-transferase, carboxylesterase, and acetylcholinesterase) compared to controls. Activities of digestive enzymes, (lipase, α-amylase, α-glucosidase, and aminopeptidase) were reduced in aphids from inoculated plants, which exhibited higher activities of superoxide dismutase, ascorbate peroxidase, and phenoloxidase, but lower catalase activity. Energy reserves (lipids, protein, and glycogen) were lower in aphids from inoculated plants, and they exhibited reduced fecundity, longevity, and reproductive periods, and a 50% reduction in the LC50 of pirimicarb. Thus, in addition to causing direct pathogenicity, inoculation of plants with B. bassiana negatively impacted A. gossypii physiology and reproductive performance and could usefully complement other strategies for managing cotton aphids on greenhouse cucumber.

An overview of irritans-mariner transposons in two Mayetiola species (Diptera: Cecidomyiidae)Original article

Wiem BEN AMARA, Salma DJEBBI, Dhia BOUKTILA, Mohamed MAKNI, Hanem MAKNI, Maha MEZGHANI-KHEMAKHEM

Eur. J. Entomol. 114: 379-390, 2017 | DOI: 10.14411/eje.2017.049

Mariner-like elements (MLEs) are widespread Class II transposable elements in insects that are subdivided into several subfamilies. In the current study, we carried out in silico analysis and in vitro experiments to identify MLEs belonging to the irritans subfamily in two cecidomyiid flies, Mayetiola destructor and M. hordei. In silico investigation of M. destructor genome allowed the identification of 25 irritans-like elements, which were mostly defective due to several mutations. These defective forms might be the remnants of active elements that ancestrally invaded the host genome. Structural analyses, including signature motifs and transposase-encoding ORFs, revealed structural heterogeneity and the presence of two full length copies. Five consensuses, reflecting the probable evolutionary groups of these elements, were constructed, based on a similarity matrix. The first consensus (Maymarcons1) belonged to Himar1-like elements reported in other insects, while the remaining four (Maymarcons2 to 5) seemed to be more specific to Cecidomyiidae. Moreover, the presence of elements belonging to the Maymarcons4 group was ascertained by PCR amplification, in both Mayetiola species, and was further identified in the Transcriptome Shotgun Assembly (TSA) of the orange fly, Sitodiplosis mosellana (Cecidomyiidae), suggesting the existence of irritans elements within the Cecidomyiidae, which were derived from an ancestral species by vertical transmission during speciation. On the other hand, consensuses that are specific to M. destructor could be derived from a more recent invasion. This study suggests that both M. destructor and M. hordei genomes have been invaded by irritans elements many times with at least two different evolutionary histories.

Functional responses and intraspecific competition in the ladybird Harmonia axyridis (Coleoptera: Coccinellidae) provided with Melanaphis sacchari (Homoptera: Aphididae) as preyOriginal article

Pengxiang WU, Jing ZHANG, Muhammad HASEEB, Shuo YAN, Lambert KANGA, Runzhi ZHANG

Eur. J. Entomol. 115: 232-241, 2018 | DOI: 10.14411/eje.2018.022

Functional responses at each developmental stage of predators and intraspecific competition associated with direct interactions among them provide insights into developing biological control strategies for pests. The functional responses of Harmonia axyridis (Pallas) at each developmental stage of Melanaphis sacchari (Zehntner) and intraspecific competition among predators were evaluated under laboratory conditions. The results showed that all stages of H. axyridis displayed a type II functional response to M. sacchari. Based on Holling's disc equation, the instantaneous searching rates were highest (a) and handling time was shortest (Th) of fourth instar larvae (a = 0.8818; Th = 3.9 min) and female adults (a = 0.9881; Th = 3.0 min) at larval and adult stages, respectively. The coefficients of mutual interference (m) assessed by the intraspecific competition equation were higher for fourth instar larvae (m = 0.4764) and female adults (m = 0.4183). The present study indicates that fourth instar and female adult were more effective stages of H. axyridis in the context of biological control but suitable predator densities need to be considered before natural enemy release.

Early successional colonizers both facilitate and inhibit the late successional colonizers in communities of dung-inhabiting insectsOriginal article

Frantisek X.J. SLADECEK, Simon T. SEGAR, Martin KONVICKA

Eur. J. Entomol. 118: 240-249, 2021 | DOI: 10.14411/eje.2021.025

The influence of early arriving species on the establishment and activity of later ones (the priority effect) is a key issue in ecological succession. Priority effects have been extensively studied in communities subject to autotrophic succession (plants, sessile animals), but only sporadically studied in communities subject to heterotrophic succession (e.g. dung or carrion inhabiting communities). We studied the influence of early successional colonizers on late successional colonizers by manipulating the successional processes in cow dung pats via delaying, and thus lowering, colonization by early successional insects. The decreased activity of early successional insects did not affect the species richness of late successional insects, but it did lead to increased abundance of colonizers. Late successional coprophagous beetles were facilitated by early successional species while larvae of late successional coprophagous flies were inhibited, presumably, by the larvae of early successional flies. We therefore propose that both facilitation and inhibition have a role to play in the heterotrophic succession of coprophilous insects. In addition, facilitation and inhibition among taxa seems to reflect their evolutionary relationships, with facilitation being prominent between phylogenetically distant lineages (early successional Diptera and late successional Coleoptera), and inhibition being more common between closely related lineages (early vs. late successional Diptera). These patterns are strikingly reminiscent of the situation in the autotrophic succession of plants.

 previous    1   2   3   4   5   6  7   8   9   10   11   ...    next