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Comparative analysis of the mitochondrial genome of Hypospila bolinoides and Lygephila dorsigera (Lepidoptera: Noctuoidea: Erebidae), with implications for their phylogenyOriginal articleMuzafar RIYAZ, Rauf Ahmad SHAH, Ignacimuthu SAVARIMUTHU, Sivasankaran KUPPUSAMYEur. J. Entomol. 120: 187-198, 2023 | DOI: 10.14411/eje.2023.024 To analyse the phylogenetic relationships of members of the family Erebidae, the mitogenomes of two species namely, Hypospila bolinoides Guenée, 1852 and Lygephila dorsigera (Walker, 1865) were sequenced. H. bolinoides and L. dorsigera have circular genomes that are 15,640 bp and 15,567 bp long, respectively. Despite their different lengths, both genomes contain an identical gene order, which includes 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes and an A+T-rich region. The nucleotide composition of the H. bolinoides mitogenome vis-à-vis the A+T rich region was 80.08%, which is higher than that of L. dorsigera (78.03%). The AT skew and GC skew were mostly negative for both species. The A+T-rich regions of H. bolinoides and L. dorsigera were 287 bp and 383 bp long, respectively, and confined to common characteristics of Noctuoidea. Concatenated sequences of 13 PCGs from 170 taxa belonging to the five families of the superfamily Noctuoidea and two butterfly mitogenomes used as outgroups were utilized for Bayesian inference (BI) and Maximum Likelihood (ML) analyses. The first-ever comprehensive analysis of the mitogenomes of the genera Lygephila (Billberg, 1820) and Hypospila (Guenée, 1852) revealed that the superfamily Noctuoidea has a well supported monophyletic relationship with (Notodontidae + (Erebidae + (Nolidae + (Euteliidae + Noctuidae))). In support of previous partial genome analyses, the present study provides phylogenomic evidence that L. dorsigera, hitherto classified as a member of the subfamily Erebinae, can be placed within the subfamily Toxocampinae. |
Behaviour and metabolism during tonic immobility (death-feigning) in Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae)Original articleHuijuan LI, Junbao WENEur. J. Entomol. 118: 322-329, 2021 | DOI: 10.14411/eje.2021.033 The antipredator behaviour, tonic immobility (TI) is a valuable defence that enables insects to increase their chance of survival and is a trade-off between fleeing and protection. How the TI strategies of insects respond to environmental factors, however, remains a largely understudied subject. In this paper the effect of four factors (mechanical stimulation, light, sound and temperature) and metabolic responses were used to evaluate TI behavioural and physiological adaptions in Eucryptorrhynchus scrobiculatus (ESCR) and Eucryptorrhynchus brandti (EBRA). In the behavioural experiment, the metaventrite, which is the stimulus-sensing region in ESCR and EBRA, was subjected to mechanical stimulation. Light lengthened the TI duration in ESCR males, while sound had the opposite effect in ESCR and EBRA. The effect of temperature on the duration of TI was variable: in ESCR, the duration was shorter at low (15°C) and high (32°C) temperatures, but in EBRA, it was longer at the low (15°C) temperature. In the metabolism experiment, ESCR and EBRA metabolic rates (MR), was significantly dependent on whether they were in a state of TI or not. The TIMR declined to 76.90% in ESCR and 71.40% in EBRA. These results indicate that TI in ESCR and EBRA differed under different external conditions and contributes to the understanding of the physiological regulation of ecological traits of insect TI. |
Evolutionary and ecological signals in Wolbachia-beetle relationships: A reviewReview£ukasz KAJTOCHEur. J. Entomol. 119: 215-226, 2022 | DOI: 10.14411/eje.2022.023 Intracellular bacteria of the genus Wolbachia are the most abundant endosymbionts infecting many arthropods, with Coleoptera being the most diverse hosts in terms of taxonomy and ecology. There has been great progress in studies on the relations between Wolbachia and beetles, however, only some of the research details the consequences of infection. In this review, I summarise the knowledge on the evolutionary relations or ecological associations between Wolbachia and its beetle hosts. These bacteria often cause cytoplasmic incompatibility in the infected hosts and are responsible for a selective sweep of the mitochondrial genomes in some beetles. Wolbachia can manipulate the sex ratio or reproduction of some species of beetles, however, it does not induce parthenogenesis, with the possible rare exception of some Naupactini. Proof of the co-evolution of Wolbachia with beetles is missing, but some aquatic groups seem to be prone to co-speciation, unlike terrestrial taxa. On the other hand, there is a growing number of studies indicating or proving horizontal transmission of Wolbachia among beetle hosts, mostly via common host plants or the foraging substrate (such as dung). Wolbachia is not alone in infecting beetles as other endosymbiotic bacteria occur in beetles (Rickettsia, Spiroplasma, Cardinium, Arsenophorus), which have often been reported as interchangeable, suggesting the infection by various bacteria is dynamic. Nonetheless, there are still many issues associated with Wolbachia that are not yet been described in beetles (like the provision of nutrition or protection against pathogens) and high-throughput sequencing should be used to improve our understanding of Wolbachia-Coleoptera relations. |
Pelle and Tube contribute to the Toll pathway-dependent antimicrobial peptide production in the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)Original articleKakeru YOKOI, Daiki KATO, Ken MIURAEur. J. Entomol. 119: 111-121, 2022 | DOI: 10.14411/eje.2022.012 Insects are solely dependent on an innate immune system. Antimicrobial peptide production is the main immune response of insects. The molecular mechanisms underlying this reaction in Drosophila melanogaster involves the induction of antimicrobial peptide genes, which is regulated by the Toll and IMD pathways. The Toll pathway is mainly activated by fungi or Gram-positive bacteria and the IMD pathway by Gram-negative bacteria. In terms of comparative immunology, we investigated the antimicrobial peptide production system in the beetle, Tribolium castaneum, which differs from that in D. melanogaster. To obtain a more detailed understanding, we examined whether Pelle and Tube, orthologues of which in D. melanogaster are the Toll pathway components, contributed to antimicrobial peptide production and immune reactions. These two genes were not induced by challenges from any type of microbe, which in this case were Gram-positive bacteria, -negative bacteria and an eukaryote. Using Pelle and Tube knockdown pupae, it was demonstrated that Pelle and Tube are involved in the induction of Cec2 as a representative Toll pathway-dependent gene in T. castaneum by Gram-positive and -negative bacteria and eukaryote challenges. Furthermore, neither Pelle nor Tube contributed to immune defences against two entomopathogenic bacteria. These results, taken together with our previous findings, led to the conclusion that the Toll pathway immune signaling reported in D. melanogaster indeed occurs in T. castaneum, and the gene sets involved in Toll signal transduction in T. castaneum did not differ significantly from those in D. melanogaster, but transduced immune signals to challenges from Gram-positive bacteria, -negative bacteria and an eukaryote, which differed from those in D. melanogaster. |
RNA interference-based characterization of Caspar, DREDD and FADD genes in immune signaling pathways of the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)Original articleKakeru YOKOI, Wataru ITO, Daiki KATO, Ken MIURAEur. J. Entomol. 119: 23-35, 2022 | DOI: 10.14411/eje.2022.003 We previously demonstrated that two immune signaling pathways, Toll and IMD, were concomitantly activated in the model beetle Tribolium castaneum by challenges to their immune system by several species of microbes, including Gram-positive and -negative bacteria as well as yeast. This contrasts with the Drosophila immune system in which more specific pathway activation depending on the type of microbe is well established. We suggest that the activation of an indiscriminate immune pathway in T. castaneum is due in part to an unselective recognition of pathogen-associated molecular patterns by the extracellular sensing modules of the two pathways. In order to obtain a more detailed understanding of the T. castaneum immune pathway, we investigated whether potential components of the T. castaneum IMD pathway, Caspar, DREDD and FADD, are involved in immune reactions triggered by microbial challenges. A sequence analysis of these three genes with the orthologues of other species, including insects, mouse and human, indicated that T. castaneum Caspar, DREDD and FADD functioned as immune signal transducers, which are usually induced by microbial challenges. However, these genes were not induced by microbial challenges. To establish whether these genes are involved in immune reactions, we used RNA interference-mediated knockdown of these genes to assess the microbial induction levels of the representative read-out antimicrobial peptide genes of the respective classes. The results indicated that these genes encode the canonical constituents of the IMD pathway of this beetle. DREDD and FADD influenced the induction of Toll-dependent antimicrobial peptide genes, providing novel crosstalk points between the two immune pathways, which appears to support indiscriminate pathway activation in T. castaneum. Furthermore, the phenotypes of DREDD or FADD knockdown pupae challenged by the two model bacterial pathogens correlated with AMP gene induction in the respective knockdowns, indicating that these intracellular factors contributed to antibacterial host defenses. |
Comparative kinetic characterization of the activity of glycosylated and non-glycosylated trypsin-like serine protease isolated from adults of Rhyzopertha dominica (Coleoptera: Bostrichidae) reared on the grain of three different cultivars of wheatOriginal articleFernanda S. ZAVALA-IBARRA, Aldo A. ARVIZU-FLORES, Oliviert MARTÍNEZ-CRUZ, Pablo S. OSUNA-AMARILLAS, José L. CÁRDENAS-LÓPEZ, Carmen L. DEL-TORO-SÁNCHEZ, Carlos R. GONZÁLEZ-RUIZ, José A. TAPIA-HERNÁNDEZ, Rey D. ITURRALDE-GARCÍA, Francisco J. CINCO-MOROYOQUIEur. J. Entomol. 120: 233-243, 2023 | DOI: 10.14411/eje.2023.026 Rhyzopertha dominica is a pest that uses trypsin-like serine protease enzymes to hydrolyse the proteins in the cereal grains on which it feeds. The present study reveals for the first time that that there are both glycosylated and non-glycosylated serine proteases. The progeny of R. dominica reared on the grain three varieties of wheat were used to fractionate their trypsin-like serine proteases using Concanavalin A affinity chromatography. The albumin fractions from the wheat cultivars used in this study were subjected to size exclusion chromatography to fractionate the albumin inhibitors that are highly specific for the serine protease activity of R. dominica. Kinetic and thermodynamic assays were used to differentiate both types of enzymes. In general, the catalytic efficiency values Vmax/Km for glycosylated proteases were higher, indicating that glycosylation increases the affinity for the substrate. Inhibition assays using wheat albumins revealed that the glycosylated enzymes had higher Ki values, indicating a low affinity for the inhibitors than the non-glycosylated enzymes. Thermodynamic analysis indicates that glycosylation increases the activation energy Ea improving the serine proteases' catalysis. Thus it is likely that R. dominica uses glycosylated proteases in order to optimize the hydrolysis of cereal proteins and nullify the action of wheat grain protease inhibitors and increase its chances of survival. |
Life and work of Ivo HodekIvo Hodek special issueEditorial articleOldøich NEDVÌD, Alois HONÌKEur. J. Entomol. 120: 157-160, 2023 | DOI: 10.14411/eje.2023.020 Ivo Hodek, who was well-known for his professional work on ladybirds (Coccinellidae) and insect ecophysiology, as well as a teacher or mentor of many entomologists, and the longest serving editor of the European Journal of Entomology died on June 11, 2021, shortly after his ninetieth birthday. Because of his important contribution to the development of European Journal of Entomology, the editorial board decided to dedicate a special virtual issue of the journal to his memory. |
Feeding behavior and mobility of carabid beetles in response to perceived risk of predationCarabidological special issueOriginal articleStefanie E. DE HEIJ, Khaldoun A. ALI, Sean M. PRAGER, Christian J. WILLENBORGEur. 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. |
Winged insects associated with the poorly studied forest fire ant Solenopsis virulens (Hymenoptera: Formicidae)Original articleThalles P.L. PEREIRA, Carolina De A. GARCIA, Freddy BRAVO, Jacques H.C. DELABIEEur. J. Entomol. 119: 439-447, 2022 | DOI: 10.14411/eje.2022.046 The present study documents new records of winged insects collected from fragments of nests of the tropical fire ant Solenopsis virulens (Smith), using a trap, which is also described in detail. The emergence chamber consisted of a 5L opaque plastic container, a 50 ml transparent vial and a 1.5 ml microcentrifuge tube. This trap captured 70 insects from 12 nests of Solenopsis virulens. They were classified into two orders, 13 families, 18 genera and 39 morphospecies. The most abundant order was Diptera, with nine families. The richest family was Cecidomyiidae, with 12 morphospecies, followed by Sciaridae with seven. Ceratopogonidae, Chironomidae, Chloropidae, Drosophilidae, Hybotidae, Phoridae and Psychodidae were also represented. Hymenoptera included a total of three families: Figitidae (Eucoilinae), Platygastridae (Scelioninae and Platygastrinae) and Diapriidae. Although the association of several genera (Diptera: 11/ Hymenoptera: 1) and families (Diptera: 1/ Hymenoptera: 1) with ant nests was recorded for the first time, it is likely that many of these insects are only fortuitous or temporary inquilines and not obligatory myrmecophiles. The trap described is also useful for catching insects that emerge from other substrates such as leaves, logs, galls, termite nests, etc. Furthermore, it could enable researchers to sample and further study important material in the laboratory and decrease the costs of sampling during field trips. |
Nearctic Anthomyzidae: Genera Mumetopia Melander and Xerocomyza gen. n. (Diptera)Original articleJindøich ROHÁÈEK, Kevin N. BARBEREur. J. Entomol. 120: 254-292, 2023 | DOI: 10.14411/eje.2023.028 The New World genus Mumetopia Melander, 1913 is redefined, redescribed and its relationships are discussed. Its Nearctic type species, M. occipitalis Melander, 1913, is revised with lectotype designation, redescribed and illustrated in detail, and its relationship, biology and distribution are treated using published and numerous new data. A new genus, Xerocomyza gen. n., is described for X. hansoni sp. n., an unusual species from high desert plains in Utah (U.S.A.), and its phylogenetic relationships are discussed: Xerocomyza is recognized as a separate lineage of Anthomyzidae most probably allied to the Carexomyza + Chamaebosca group clade (sensu Barber & Roháèek, 2020, Arthropod Syst. Phylogeny 78: 69-109). Biology and distribution of X. hansoni are given on the basis of limited label data from type specimens. |
The association of the development of the internal reproductive organs of male desert locusts, Schistocerca gregaria (Orthoptera: Acrididae), with age, phase and the effect of exposure to pheromonesOriginal articleSatoshi HIROYOSHI, Takayuki MITSUNAGA, Gadi V.P. REDDYEur. J. Entomol. 119: 300-308, 2022 | DOI: 10.14411/eje.2022.031 The regulation of the development of the male reproductive organs in insects is still an open question. Although the desert locust, Schistocerca gregaria, has been extensively examined, there is little information on the effects of phase and pheromones on the development of the male reproductive organs. This study clarified the association of these two factors with reproductive development (length or width of each organ) of the testis, testicular follicles, accessory glands, and seminal vesicles in this locust. The width of the follicles and width and length of the accessory gland mass are significantly associated with phase (solitary or gregarious). Developmen of all reproductive organs is age dependent as these organs developed in the adult stage. The development of follicles and accessory glands (width) in males in the first two weeks of adulthood was promoted by exposing them to pheromones from mature adults, but not from nymphs. These results indicate the incidence of male reproductive development is associated with phase and affected by pheromones. |
Efficiency of foraging behavior in the ant genus Messor (Hymenoptera: Formicidae: Myrmicinae) in response to food distributionOriginal articleAbderrahmane EL BOUKHRISSI, Ahmed TAHERI, Nard BENNAS, Joaquín L. REYES-LÓPEZEur. J. Entomol. 120: 357-365, 2023 | DOI: 10.14411/eje.2023.039 Harvester ants are known to be species that collect seeds of plants and store them in underground chambers. Workers forage solitarily or in groups, and the intensity of their foraging depends, among other things, on the rate of food intake. To evaluate the efficiency of foraging in response to food distribution, we studied the foraging rate on different distributions of seeds in three species of the genus Messor, M. barbarus (Linnaeus, 1767), M. marocanus Santschi, 1927 and M. sanctus Emery, 1921. Foraging rates were higher on more clumped seed distributions in all studied colonies. The number of foragers did not influence the foraging behavior of these colonies in response to seed distribution. Monitoring the foraging rate over time revealed that it remains stable for all three species, except for the initial and final stages of bait consumption. Additionally, M. marocanus collected seeds from several sources simultaneously, whereas the other two species collected seeds from one resource at a time. |
Time measurement in insect photoperiodism: The role of photophase duration and light intensityIvo Hodek special issueReviewDavid SAUNDERSEur. 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. |
North vs. South: Contrasting patterns in the phenotypic plasticity of the firebug Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae) at the latitudinal extremes of its distribution rangeIvo Hodek special issueOriginal articleDmitry KUTCHEROV, Elena B. LOPATINAEur. J. Entomol. 119: 454-465, 2022 | DOI: 10.14411/eje.2022.048 In widely distributed insects, some life-history traits are conserved across the whole distribution range and are considered species-specific while other such traits differ geographically. This interplay of geographic variation and phenotypic conservatism is poorly understood even in relatively well-studied model species. Furthermore, a careful study may reveal that conventionally stable traits, such as the lower temperature threshold for development and the sum of degree-days, are both geographically variable and environmentally plastic. We studied how photoperiodic conditions and temperature jointly affect immature development, adult body size and wing polymorphism in two populations of the firebug from the opposite latitudinal margins of this species' range. All the three traits rarely clearly differ under short-day and long-day conditions or between north and south. Instead, we find prevalent temperature-by-photoperiod and temperature-by-origin interactions, which emphasize that it is not only the absolute values of these traits but the degree of their temperature-dependence, or thermal plasticity, that varies in time (in response to seasonal changes in day length) and in space (along latitudinal gradients). These results indicate that caution should be exercised when extrapolating any life-history traits in P. apterus beyond the season when and the location where these were measured. In particular, the use of a constant lower temperature threshold coupled with a constant sum of degree-days is likely to oversimplify the diversity of current and projected phenological patterns in this species. |
Establishment of a primary cell culture of Thrips palmi (Thysanoptera: Thripidae)Short CommunicationAmalendu GHOSH, Heena DHALL, Sumit JANGRAEur. J. Entomol. 120: 297-303, 2023 | DOI: 10.14411/eje.2023.030 Thrips palmi (Thysanoptera: Thripidae) is an important pest of vegetables, ornamental plants and fruit crops. In addition to the direct damage caused by feeding, it transmits several tospoviruses. The absence of an in vitro assay system is a major bottleneck in investigating thrips-tospovirus interactions. The present study reports the establishment of a primary cell culture of T. palmi, which was initiated using embryonic tissue as an explant in modified Kimura's medium. Fibroblast-like cells began to be produced 3 h after tissue implantation and were the dominant cell type. They grew in size and number and covered most of the surface. This primary cell culture survived for 37 days providing sufficient time for analytical molecular studies on the replication of tospovirus and interactions with the vector components. |
Cytogenetic characterization of Diachasmimorpha longicaudata (Hymenoptera: Braconidae), a parasitoid wasp used as a biological control agentLeonela CARABAJAL PALADINO, Alba PAPESCHI, Silvia LANZAVECCHIA, Jorge CLADERA, María José BRESSAEur. J. Entomol. 110 (3): 401-409, 2013 | DOI: 10.14411/eje.2013.054 Diachasmimorpha longicaudata (Hymenoptera: Braconidae) is a parasitoid wasp widely used in the biological control of fruit flies. In this paper, we present a detailed analysis of the karyotype of this species based on the results of classical and molecular cytogenetic techniques. The cytogenetic analysis confirmed the male and female chromosome numbers previously reported (n = 20, 2n = 40). The entire short arm of most chromosomes is made up of a large constitutive heterochromatic segment. The high heterochromatin content differentiates D. longicaudata from other braconid species. Fluorescence in situ hybridization (FISH) using autologous 18S rDNA probes revealed six clusters of rDNA, i.e. six nucleolar organizer regions (NORs), in the heterochromatic short arms of different chromosomes in the haploid male karyotype. This number is exceptionally high for Hymenoptera, which usually have two NORs in the diploid complement. It is noteworthy that these rDNA-FISH experiments represent the first use of this technique on a braconid species using autologous probes. Since Ag-NOR-bands were coincident with C-positive bands on metaphase chromosomes, it was not possible to identify active nucleoli. The physical characteristics of the D. longicaudata karyotype, especially the content and distribution of heterochromatin and the number and location of rDNA clusters, contribute to a better understanding of the structure and organization of braconid chromosomes and provide a basis for genomic and evolutionary studies. |
Molecular cloning and functional analyses of an adhesion molecule, neuroglian, in Mythimna separata (Lepidoptera: Noctuidae)Original articleKakeru YOKOI, Yoshiaki KATO, Masahiro SUZUKI, Ken MIURAEur. J. Entomol. 115: 157-166, 2018 | DOI: 10.14411/eje.2018.015 Insect cellular immune reaction, which generally includes phagocytosis, encapsulation and nodule formation, is achieved by hemocytes circulating in insect haemolymph. The shift of hemocytes from the normal phase to the adhering phase is an important process in the cellular immune reaction, which includes the attachment of hemocytes to foreign surfaces or other hemocytes via adhesion factors. Neuroglian is one of the adhering factors associated with encapsulation in Manduca sexta and Drosophila melanogaster. Here we studied the localization of neuroglian (MsNrg) in Mythimna separata and its functional role in the cellular immune reaction. The distribution of MsNrg mRNA between hemocyte populations was determined using real-time quantitative reverse transcription PCR and in situ hybridization, which revealed that MsNrg was highly expressed in adhering hemocytes, especially in plasmatocytes. Unexpectedly, the transcript was observed as well in non-adhering hemocytes, implying neuroglian has a function in non-adhering hemocytes. Moreover, we showed that the amount of MsNrg mRNA was not changed by injections of either biotic or abiotic non-selves. Fewer latex beads were fully encapsulated by hemocytes in larvae treated with MsNrg double-stranded RNA than in control larvae, but their ability to achieve phagocytosis and nodule formation remained unchanged by the MsNrg knockdown. These results indicate that the function of neuroglian in the cellular immune reaction is conserved in D. melanogaster and lepidopteran species, and neuroglian in non-adhering hemocytes could possess unidentified function. |
Effect of low-temperature storage on the life history parameters and voracity of Hippodamia variegata (Coleoptera: Coccinellidae)Original articleSamane SAKAKI, Mohammad Amin JALALI, Hashem KAMALI, Oldøich NEDVÌDEur. J. Entomol. 116: 10-15, 2019 | DOI: 10.14411/eje.2019.002 For biological control it is necessary to store mass-reared biological control agents when the demand is low. The objective of this study is to increase their shelf life without significantly reducing their fitness. The ladybird Hippodamia variegata is a widespread and voracious aphidophagous predator, with an important role in decreasing the abundance of pest aphids in many parts of the world. We investigated the effect of storage at three temperatures: constant 1°C, constant 6°C, and an alternating thermal regime of 12°C/0°C (the higher temperature for 12 h and the lower one for another 12 h). They were exposed to each of the temperature regimes for either 15, 25, 35, 45 or 60 days. We recorded survival, pre-oviposition period, fecundity and voracity of adult H. variegata following storage. The survival of adult beetles significantly declined with increasing storage duration at all three temperatures. Storage at 6°C up to 35 days and at 12°C/0°C up to 45 days had no significant effects on the fecundity of the ladybirds, but storage for longer significantly decreased fecundity. Beetles stored at 1°C for any of the durations had significantly lower fecundities. Prolonged cold storage caused an increase in the pre-oviposition period at all storage temperatures. Generally, 6°C and 12°C/0°C are the best temperatures for storing the ladybirds as they had the least negative effect on their fitness. The results of this research can help in improving the quality of H. variegata stored for use as biological control agents in the following season. |
Distribution and dispersal of the invasive Asian chestnut gall wasp, Dryocosmus kuriphilus (Hymenoptera: Cynipidae), across the heterogeneous landscape of the Iberian PeninsulaOriginal articleDiego GIL-TAPETADO, José F. GÓMEZ, Francisco J. CABRERO-SAÑUDO, José L. NIEVES-ALDREYEur. J. Entomol. 115: 575-586, 2018 | DOI: 10.14411/eje.2018.055 Dryocosmus kuriphilus (Hymenoptera: Cynipidae), also known as the Asian chestnut gall wasp, is a non-native invasive species that has recently appeared in many regions of Europe, including the Iberian Peninsula. This species is an important pest of chestnut trees in several regions and is of concern for foresters in these areas. The results of this research revealed 14 different hotspots of infestation of D. kuriphilus and resulted in the development of models that predict the distribution of D. kuriphilus in Spain over the next 37 years (2019-2055). These results indicate a rapid spread in all Spanish chestnut forests and identify areas that are theoretically highly suitable and susceptible to colonization by this cynipid based on predictions of three different niche models. Although D. kuriphilus is able to induce galls on all chestnut trees, the models indicate that there are differences in the suitability of the different regions for this species. This differential suitability results in some areas having better environmental conditions than others for D. kuriphilus, which is a factor that should be taken into account in its management and biological control. This study of the current distribution, patterns of dispersal using GIS and potentially suitable areas for D. kuriphilus, using niche models will assist in the management and control of this pest in Spain. |
Effects of 20-hydroxyecdysone on the development and morphology of the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)Original articleNujira TATUN, Phiraya KUMDI, Jatuporn TUNGJITWITAYAKUL, Sho SAKURAIEur. J. Entomol. 115: 424-431, 2018 | DOI: 10.14411/eje.2018.042 The red flour beetle, Tribolium castaneum, is a pest of stored products. It is also regarded as a model species for studying development, genetics, biology, physiology and biochemistry. Recently, it has become a model for use in RNA interference experiments. 20-hydroxyecdysone (20E) is involved in insect metamorphosis and its role in organ development in T. castaneum are based on hormonal treatment in conjunction with RNAi. However, information on the biological, morphological and physiological effects of 20E on T. castaneum is still limited. This study reveals the responses of T. castaneum larvae to injections with various doses of 20E (100, 200, 300, 400 and 500 ng / insect). The results show that larvae injected with 20E reached the prepupal, pupal and adult stages earlier than the control group. Different degrees of morphological change were observed in nine traits, including the appearance of pupal prothetelic organs in the larvae. Moreover, an injection of a high dose of 20E reduced the body weights of the resulting insects at each stage, as well as the length and width of elytra. The enzymatic activity of α-amylase in the resulting adults also decreased significantly. This indicates that injection of 20E caused precocious metamorphosis in T. castaneum by inducing changes in morphology and α-amylase activity, and the optimal concentrations that induce such phenomena were in the range of 100-200 ng / insect. Further investigations are needed to examine the roles of 20E in the regulation of α-amylase in T. castaneum. |
Laboratory rearing of Sycanus annulicornis (Hemiptera: Reduviidae) on two species of prey: Differences in its biology and efficiency as a predator of the nettle caterpillar pest Setothosea asigna (Lepidoptera: Limacodidae)Original articleAbdul SAHID, Wahyu D. NATAWIGENA, HERSANTI, SUDARJATEur. J. Entomol. 115: 208-216, 2018 | DOI: 10.14411/eje.2018.019 Setothosea asigna van Eecke is a dominant defoliator pest in oil palm plantations. To control this pest, a generalist predatory bug, Sycanus annulicornis Dohrn, was used as it is easy to rear on several different species of prey. In this study, we evaluated the influence of different prey on the biology and the ability of S. annulicornis to attack and kill the nettle caterpillar pest S. asigna. Based on laboratory rearing, the larvae of Crocidolomia pavonana F. (Lepidoptera: Crambidae) is a suitable prey for both the growth and development of S. annulicornis, as its nymphal development is shorter (74.0 ± 7.3 days) and adult longevity longer (81.0 ± 9.0 days for male and 64.8 ± 12.4 days for female, respectively) than when reared on the larvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) (44.0 ± 16.7 days for male and 52.6 ± 14.4 days for female). However, S. annulicornis reared on T. molitor larvae attacked 2.0-2.2 larvae of S. asigna per day, which is more than the 1.6-1.7 larvae per day of those reared on C. pavonana, which indicates that the larvae of T. molitor are a more effective diet for rearing S. annulicornis as biocontrol agent for the S. asigna. |
The role of iron (Fe) in the population dynamics of pistachio psyllid, Agonoscena pistaciae (Hemiptera: Aphalaridae) in Pistacia orchardsOriginal articleHossein DEHGHANI-YAKHDANI, Shahzad IRANIPOUR, Mohammad Reza MEHRNEJAD, Reza FARSHBAF-POURABADEur. J. Entomol. 116: 194-200, 2019 | DOI: 10.14411/eje.2019.021 The common pistachio psyllid (CPP) is thought to respond to nutrient availability in pistachio trees. We determined the effect of a deficiency of leaf iron (Fe) has on the abundance of the pistachio psyllid at a regional scale. First, we monitored the abundance pistachio psyllid in four pistachio orchards (24 trees as 24 repetitions) located in Maybod County, Yazd province in the centre of Iran and then measured leaf nutrient levels. Orchards were located up to 2.6 km apart. Multivariate regressions were used to determine the relationship between leaf nutrients and CPP population growth. The results indicate that the number of psyllid eggs and population growth rate of the nymphs was negatively correlated with Fe levels in the leaves, while peak numbers of psyllid eggs were positively correlated with the levels of Cu in the leaves. In a manipulative field experiment, we conducted two experiments: (1) pistachio trees treated with iron compared with control trees, and (2) pistachio trees previously treated with iron were treated with ammonium sulphate and compared with trees treated with ammonium sulphate. In the first experiment, psyllids in leaf disc-cages had a significantly greater intrinsic rate of population increase and net reproductive rate on Fe-treated trees than the control trees (Stage 1). In the second experiment, psyllids in leaf disc-cages had similar intrinsic rates of population increase and net reproduction both on the ammonium sulphate treated trees (control) and those previously treated with iron. This indicates that iron may have reacted negatively with nitrogen content of the leaves. In general, these findings indicate that when there is a deficiency of iron in the leaves, the application of nitrogen fertilizer had little effect on the performance of CPP and may have played a minor role in the population dynamics of CPP, but the application of a Fe fertilizer without considering the nitrogen content of the leaves may lead to a population outbreak. |
Infection-induced molecular pattern recognition proteins in larvae of Protaetia brevitarsis seulensis (Coleoptera: Cetoniidae)Original articleKyeongrin BANG, Jiae LEE, Sejung HWANG, Youngwoo CHO, Jangwoo PARK, Saeyoull CHOEur. J. Entomol. 119: 77-84, 2022 | DOI: 10.14411/eje.2022.008 We cloned and sequenced full-length peptidoglycan recognition protein (PGRP)-like cDNAs, named PS PGRP-SA(a)-like, PS PGRP-SA(b)-like, PS PGRP-SB1-like and PS PGRP-SC-like, from Protaetia brevitarsis seulensis. The amino acid sequences of PS PGRPs share 32.03-47.93% homology with those of PGRP family members in insects and mammals, including humans. We identified a conserved consensus sequence for amidase activity (His; H-Tyr; Y-His; H-Thr; T-Cys; C) and residues for binding peptidoglycan (PGN), one of the major bacterial cell wall components, including Asp (D) and Phe (F) for Lys-type PGN; and Gly(G), Trp (W) and Arg (R) for DAP-type PGN. The topological structures of PS PGRP-SA(a)-like, PS PGRP-SA(b)-like and PS PGRP-SC-like proteins are structurally similar to those of Drosophila melanogaster PGRP-SA, which has three α-helices and six β-strands. The β-strands are located in a central region and helix α1 on the back and peripheral α2 and α3 helices are on the front. The three α-helices and six β-strands are also present in PS PGRP-SB1-like, but the topological structure differs from that of typical PGRP. Significantly increased levels of PS PGRP-SA (a)-like and PS PGRP-SA (b)-like mRNA were recorded when Gram-positive bacteria or yeast cells were injected into larvae. PS PGRP-SB1-like mRNA levels were up-regulated by infection by all three pathogens; however, expression of PS PGRP-SC-like mRNA was increased 20- or 30-fold only shortly after injection with Gram-negative bacteria. |
Taxonomic revision of the highly threatened Eumerus tricolor species group (Diptera: Syrphidae) in Southeast Europe, with insights into the conservation of the genus EumerusOriginal articleAna GRKOVIÆ, Jeroen VAN STEENIS, Marija MILIÈIÆ, Nata¹a KOÈI© TUBIÆ, Mihajla DJAN, Sne¾ana RADENKOVIÆ, Ante VUJIÆEur. 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 Vujiæ & Grkoviæ, sp. n. from Serbia and E. nigrorufus Grkoviæ & Vujiæ, 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. |
Seasonal shift in carabid phenology over a period of 18 yearsOriginal articleUlrich IRMLEREur. J. Entomol. 119: 183-I, 2022 | DOI: 10.14411/eje.2022.020 The present study is based on a 20-year study of fields that were previously farmed conventionally and then changed to being farmed organically and a 10-year study of a conventionally farmed field in south-eastern and central Schleswig-Holstein, North Germany, respectively. The carabid beetles were sampled throughout each year using pitfall traps. The analysis aimed to study the changes in the phenology in terms of activity-density associated with changing climate. Climate data revealed an increase in temperature during the period of this study, which was not significant during the single study periods, but significant if a longer period of 70 years is considered. In particular, spring temperatures (March/April) increased. Approximately 36% of the species became active earlier. For 25% of the species their earlier start was not significant but nevertheless associated with temperature increase in spring or the number of cold days (< 0°C) and warm days (> 5°C) in March/April. In total, the earlier start of 69% of the species can in some way be associated with a change in climate in spring. Species with a flexible response to temperature were mostly indifferent to the temperature increase. Comparisons of the data over the 30-year period indicate that the process lasted for at least one to three decades. It is likely that the changes in biological processes caused by global climate change will affect the composition of species and competition between them in the future. |
Mitochondrial DNA variation of Drosophila obscura (Diptera: Drosophilidae) across EuropeOriginal articlePavle ERIÆ, Marina STAMENKOVIÆ-RADAK, Milan DRAGIÆEVIÆ, Maaria KANKARE, Megan A. WALLACE, Marija SAVIÆ VESELINOVIÆ, Mihailo JELIÆEur. 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. |
Comparative suitability of aphids, thrips and mites as prey for the flower bug Orius sauteri (Hemiptera: Anthocoridae)Su WANG, J.P. MICHAUD, Fan ZHANGEur. J. Entomol. 111 (2): 221-226, 2014 | DOI: 10.14411/eje.2014.031 The predatory bug Orius sauteri (Poppius) (Hemiptera: Anthocoridae) is an important biological control agent in Asia that is often released on field crops and in greenhouses to control pests on vegetable and ornamental plants. This study compared the developmental and reproductive performance of O. sauteri on monotypic diets of four aphid species, western flower thrips, and two-spotted spider mite. Thrips emerged as the optimal prey type, consistent with findings for many other Orius spp. A diet of Frankliniella occidentalis (Pergande) yielded the fastest development, largest adult body size, shortest pre-oviposition period, and highest fecundity and longevity. Tetranychus urticae (Koch) was the next most suitable prey by most performance measures. Among aphids, Myzus persicae (Sulzer) was the most suitable and Aphis gossypii Glover the least suitable, with Aphis craccivora Koch and Megoura japonica (Matsumura) intermediate. Female O. sauteri were larger than males and female body mass varied more with prey type than did that of males. Despite the variation in performance among prey, all prey species yielded equally good juvenile survival and none would be expected to negatively impact the numerical response of O. sauteri in biological control applications where these arthropods form part of the prey complex. |
Insect photoperiodism: Seasonal development on a revolving planetReviewDavid SAUNDERSEur. 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. |
Structure of canopy and ground-dwelling arthropod communities in olive orchards is determined by the type of soil coverOriginal articleJesús CASTRO, Francisco S. TORTOSA, Antonio J. CARPIOEur. J. Entomol. 118: 159-170, 2021 | DOI: 10.14411/eje.2021.017 The intensification of agriculture in olive groves, especially the modification or elimination of spontaneous vegetation, alters the relationships in arthropod communities and reduces their interactions and ecosystem services. This study was carried out in nine olive groves in which there was either a planted cover crop, spontaneous cover crop or bare ground. The interactions of ground-dwelling, canopy and flying arthropods in trophic webs were calculated for each olive grove soil management regime at the family level taking into consideration their different functional traits: feeding guilds, specific agricultural traits and trophic level. Olive groves with spontaneous cover had trophic webs with a higher number of plausible links between arthropod families and a more balanced distribution of specimens among trophic levels compared to those with planted cover and bare ground. There was a similar number of arthropod families consisting of both pests and their natural enemies in the planted cover regime, while olive groves with bare ground had simpler trophic webs. The complexity of plausible trophic links was greater in olive groves with spontaneous plant cover despite the similar values for family richness in the three-olive grove soil management regimes. Qualitative values (such as functional traits) were more diverse in agroecosystems with spontaneous plant cover in which there were more sources of food. |
Genome-wide screening of genes involved in programming diapause in the next generation in silkworm, Bombyx mori (Lepidoptera: Bombycidae)Original articleYuichi EGI, Katsuhiko SAKAMOTOEur. J. Entomol. 119: 405-412, 2022 | DOI: 10.14411/eje.2022.042 Maternal silkworms (Bombyx mori) of bivoltine strains are destined to produce either diapause or non-diapause eggs depending on environmental factors, such as, temperature and photoperiod experienced during the egg and larval stages. However, the molecular mechanisms that program diapause, which depend on information about the environment, remain unclear. We aimed to identify genes that are involved in programming diapause in the next generation in bivoltine silkworms. We therefore screened differentially expressed genes (DEGs) in the larval brains of diapause- and non-diapause-egg producers kept under three different diapause-inducing conditions using cap analysis of gene expression. Under each condition, only temperature, illumination or photoperiod was changed during the egg or larval stage as a diapause-controlling stimulus to induce the production of diapause or non-diapause eggs. We then verified the expression of DEGs that were common to all the three conditions using real-time quantitative PCR. We investigated the functional involvement of candidate genes in programming diapause using double-stranded RNA interference (RNAi) for gene knockdown. The results showed more abundant juvenile hormone acid methyltransferase (Jhamt) and proton-coupled folate transporter (Pcft) gene expression in the brains of fifth instar larvae of producers of diapause eggs than those of non-diapause eggs under the three conditions. Furthermore, RNAi against either of these genes significantly decreased the incidence of diapause in the next generation. These findings indicate that both Jhamt and Pcft are involved in the programming of diapause in the silkworm brain. These genes could function in retaining information that leads to diapause in the next generation. |



