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Araneae communities associated with the canopies of chestnut trees in the northeastern part of Portugal: The influence of soil management practicesJacinto BENHADI-MARIN, José Alberto PEREIRA, José-Antonio BARRIENTOS, Albino BENTO, Sónia A.P. SANTOSEur. J. Entomol. 110 (3): 501-508, 2013 | DOI: 10.14411/eje.2013.066 Chestnut (Castanea sativa Mill.) is one of the economically more important trees in the north of Portugal. Spiders, as generalist predators, are potential controlling agents of pests, yet the composition of the community of spiders associated with this crop is only poorly known. The objective of this study was to determine the spider communities in the canopies of chestnut trees subject to three different soil management practices in northeastern Portugal. Three chestnut groves each subject to a different agricultural practice (grazed, tilled or untilled) were studied in 2008 and 2009. The Araneae communities were sampled by beating the branches and the individuals collected were identified to family and species when possible. To investigate the structure of the spider community in each grove the abundance and family richness of spiders were calculated and compared between managements. In total, 4172 spiders were collected and, in both years, the three most abundant families were Araneidae, Philodromidae and Linyphiidae. In 2008, there was a greater abundance of spiders in the grazed, followed by the tilled and untilled groves, but no significant differences among groves. However, in 2009 there was a greater abundance of spiders in the tilled grove, followed by grazed and untilled groves and the differences between the untilled and the other two groves were significant. Araniella, Oxyopes and Anyphaena were the most abundant genera in the three groves. This study showed that soil management may influence the diversity of spiders, but the effects were weak and not consistent between years. The reduction or absence of a suitable habitat for spiders under the trees in the tilled treatment might have resulted in the spiders migrating up into the canopy. However, based on the weak effects on spider abundance recorded and its potentially adverse effects on soils, tillage is not recommended for managing the incidence of pests in chestnut groves. |
Temperature-dependent functional response of Aenasius bambawalei (Hymenoptera: Encyrtidae) to different population densities of the cotton mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae)Original articleRazieh JOODAKI, Nooshin ZANDI-SOHANI, Sara ZARGHAMI, Fatemeh YARAHMADIEur. J. Entomol. 115: 326-331, 2018 | DOI: 10.14411/eje.2018.032 The functional response of Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) to different population densities of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) was investigated under laboratory conditions of 65 ± 5% R.H., a photoperiod of 14L : 10D and at temperatures of 25, 30 and 35 ± 1°C. Two, 4, 6, 8, 16, 32 and 64 third instar nymphs of P. solenopsis were exposed to newly emerged mated female parasitoids for 24 h. The parasitoid exhibited a type II functional response at all temperatures. The searching efficiencies (a) and handling times (Th) were 0.1818 h-1 and 5.0012 h at 25°C, 0.1382 h-1 and 3.2807 h at 30°C, and 0.2097 h-1 and 2.3635 h at 35°C, respectively. The maximum attack rates (T/Th) were 4.8, 7.3 and 10.2 nymphs at 25, 30 and 35°C, respectively. This indicates that A. bambawalei is more likely to be an effective biological control agent of P. solenopsis in warm seasons. |
Water relations and drought sensitivity of Folsomia candida eggs (Collembola: Isotomidae)Original articleMartin HOLMSTRUPEur. J. Entomol. 116: 229-234, 2019 | DOI: 10.14411/eje.2019.025 Drought tolerance of juvenile and adult life stages is relatively well understood, but very little is known about the tolerance of eggs to drought in this group of animals. The aim of the present study was therefore to investigate the water relations and drought sensitivity of eggs of the hygrophilic springtail, Folsomia candida Willem, 1902 (Isotomidae), exposed to a range of soil water potentials above and below the permanent wilting point of plants (-1.5 MPa). Under saturated conditions, eggs absorbed water during development and increased water content from 1.1 to 2.9 mg mg-1 dry weight. By increasing drought conditions, water absorption was gradually reduced and was nullified approximately at the soil water potential equivalent to the osmolality of egg fluids (630 mOsm corresponding to -1.53 MPa). Eggs had a lower permeability for water (68 ± 13 µg water cm-2 h-1 mm Hg-1) than adults (about 400 µg water cm-2 h-1 mm Hg-1), but eggs were much more sensitive to drought than adults. Eggs did not survive exposure to -1.5 MPa, whereas adults readily survive this level of drought by absorbing water vapour. In conclusion, eggs of F. candida are sensitive to drought and would perish if soil water potential in the field approaches the wilting point of plants, which is often reached during summer droughts. The persistence of this species depends on the survival of post-embryonic life stages. |
Daily survival and dispersal of adult Rhagonycha fulva (Coleoptera: Cantharidae) in a wooded agricultural landscapeOriginal articleLaura E. RODWELL, Jennifer J. DAY, Christopher W. FOSTER, Graham J. HOLLOWAYEur. 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. |
Parental care and offspring survival in Pterostichus anthracinus (Coleoptera: Carabidae): An experimental studyOriginal articleFelix N. KOLESNIKOV, Arevik N. KARAMYANEur. J. Entomol. 116: 33-41, 2019 | DOI: 10.14411/eje.2019.004 Parental care in which females attend their offspring is recorded in over 30 species of ground beetles. Despite this, there is no quantitative data on the fate of the offspring when the mother is experimentally removed. This paper investigates parental care in Pterostichus anthracinus (Coleoptera: Carabidae). The objectives of the study were to estimate: (1) egg survival when the female is removed; (2) the ability of females to defend their eggs from attack by predators; (3) the ability of females to repair a damaged nest in which egg attendance takes place. In the laboratory, the reproductive activity of P. anthracinus lasted four months (from May till August) and peaked in late June. Mean (± SE) number of eggs in each clutch was 25.25 ± 2.19. All of the egg clutches were guarded by a female. Female attendance had no effect on egg mortality due to microbial attack. The duration of embryonic development lasted on average 5.2-5.3 days, and did not differ between the groups with and without maternal care. In P. anthracinus maternal care is important in preventing egg mortality due to predators. In the laboratory the percentage mortality of eggs without maternal care due to predators was 100%. In the group in which females attended their eggs, percentage mortality of offspring due to predation was about 51%. Female ability to repair damaged nests is important in preventing dehydration and reducing predation pressure. This laboratory study provides the first quantitative data on the importance of maternal care in ground beetles in determining the survival of their offspring. |
Mating activity of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae) in natureOriginal articleAlois HONĚK, Zdenka MARTINKOVÁ, Marek BRABECEur. J. Entomol. 116: 187-193, 2019 | DOI: 10.14411/eje.2019.020 The mating behaviour of Pyrrhocoris apterus in the laboratory is well studied, but little is known about it under natural conditions. In natural populations in Central Europe, overwintered adults start copulating in March and continue until their death. Caged females, kept under natural conditions in the permanent presence of males, copulated repeatedly. Their mating activity increased sharply until early April, then very slowly until the end of June and then declined as the females die-off. Half of copulations were short (< 5 h) and only 9% were longer than 1 day. By contrast, in natural populations, mating activity (percentage of individuals involved in copula) reached its maximum in April and then decreased until early July, when the overwintered adults die. The decline in mating frequency (percentage of adults involved in copula) was associated with a decrease in the availability of receptive females towards the end of the mating period. For a female, repeated copulation is necessary because sperm is nearly depleted after insemination of 3-5 egg batches. |
Functional responses and intraspecific competition in the ladybird Harmonia axyridis (Coleoptera: Coccinellidae) provided with Melanaphis sacchari (Homoptera: Aphididae) as preyOriginal articlePengxiang WU, Jing ZHANG, Muhammad HASEEB, Shuo YAN, Lambert KANGA, Runzhi ZHANGEur. 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. |
Feeding behaviour of young larvae of Pieris rapae crucivora (Lepidoptera: Pieridae) and its effect on parasitism by Cotesia glomerata (Hymenoptera: Braconidae)Original articleAya NAKAYAMA, Keiji NAKAMURA, Jun TAGAWAEur. J. Entomol. 115: 380-386, 2018 | DOI: 10.14411/eje.2018.038 We investigated the effect of the feeding behaviour of young larvae of Pieris rapae crucivora Boisduval (Pieridae) on parasitism by the parasitoid wasp, Cotesia glomerata (L.) (Braconidae). Young, 1st-3rd instar larvae used approximately three sites for feeding each day. When not feeding, they moved a short distance away from the feeding sites (= feeding marks) and rested. For first, second and third instar larvae, the distances from the new mark, made within 24 h, to larva at rest were, respectively, about 3.5 mm, 5 mm and more than 10 mm. To resume feeding, they moved back to one of the former feeding sites or a new site. The percentage of the feeding marks older than 24 h that attracted parasitoids was less than 50%. Time spent searching for hosts by a parasitoid was short. Larvae placed 5 mm or more from a feeding mark were less parasitized than the larvae placed near a mark. The number of feeding marks affected parasitism. When comparing single-marked and triple-marked leaves, the percentage parasitism of the larvae on the latter was significantly lower than that of the larvae on the former. On triple-marked leaves, parasitoids visited each mark unevenly. Accordingly, the time spent searching each mark differed significantly among the marks. Because of this confusing effect, hosts are considered to be reducing the risk of parasitism. Our results demonstrate that the feeding habits of young larvae of P. rapae crucivora are adaptive in terms of reducing the risk of parasitism by C. glomerata. |
Burial-induced changes in the seed preferences of carabid beetles (Coleoptera: Carabidae)Original articlePavel SASKA, Alois HONĚK, Hana FOFFOVÁ, Zdenka MARTINKOVÁEur. J. Entomol. 116: 133-140, 2019 | DOI: 10.14411/eje.2019.015 Seeds of many species of plants may survive for a long time in the soil and germinate when brought to the surface, but whether they are subsequently eaten by seed predators is unknown. We examined the preferences of three species of carabids (Coleoptera: Carabidae) for 25 species of seeds and determined the difference in palatability between freshly dispersed and those buried for six years. The stability of their preferences was tested using a collection of seeds of different species, each of which was offered fresh or after being buried. Carabid beetles readily accepted previously buried seeds as food. In total, Pseudoophonus rufipes and Amara littorea ate more fresh seeds than previously buried seeds, while the opposite was true for Harpalus affinis. The seeds of some species were even more attractive to carabids after burial than in the fresh state. For all the species of carabids tested, the diet breadth was similar when the beetles were fed fresh or buried seeds, but the preferences for fresh and buried seed of particular species were correlated only in P. rufipes and A. littorea. We measured the seed characteristics (mass and viability) likely to be associated with the loss of attractiveness to carabids during burial. The change in carabid consumption was not related to changes in any of these characteristics. This finding indicates that factors responsible for variation in seed acceptability are complex. This study provides the first conclusive evidence that invertebrate seed predators will feed on seeds from seed banks, although they prefer fresh seeds. |
Puncture vs. reflex bleeding: Haemolymph composition reveals significant differences among ladybird species (Coleoptera: Coccinellidae), but not between sampling methodsOriginal articleMichal KNAPP, Pavel DOBE©, Michal ŘEŘICHA, Pavel HYR©LEur. J. Entomol. 115: 1-6, 2018 | DOI: 10.14411/eje.2018.001 Reflex bleeding is one of the many anti-predation behavioural tactics used by insects. This behaviour is recorded widely in several insect taxa and provides scientists with an interesting opportunity for easily obtaining samples of haemolymph for physiological experiments. However, there is no good evidence that haemolymph and reflex blood have the same characteristics. In this study, we compared three basic characteristics of reflex blood and haemolymph collected from the body cavity, of three species of ladybirds: Harmonia axyridis, Coccinella septempunctata and Ceratomegilla undecimnotata. In the reflex blood we recorded the same concentration of haemocytes and total protein, and level of antimicrobial activity against Escherichia coli as in samples of haemolymph collected from within the body cavity. Therefore, reflex blood is a promising source of haemolymph for use in many physiological and immunological studies. It is the best way of collecting haemolymph if one wants to avoid challenging the immune system and concurrently also enables one to repeatedly collect haemolymph from one individual without injuring it, which would initiate repair mechanisms. The interspecific comparison indicates significant differences among the species studied in three characteristics measured. Interestingly, the native species Ceratomegilla undecimnotata has nearly as effective immune system as the invasive Harmonia axyridis based on the level of antibacterial activity against Escherichia coli. |
Demography of the endangered butterfly Euphydryas aurinia (Lepidoptera: Nymphalidae): A case study of populations in sub-Mediterranean dry calcareous grasslandsOriginal articleJure JUGOVIC, Costanza UBONI, Sara ZUPAN, Martina LU®NIKEur. J. Entomol. 115: 493-503, 2018 | DOI: 10.14411/eje.2018.049 We studied a population of the regionally endangered marsh fritillary butterfly Euphydryas aurinia inhabiting a system of loosely connected dry calcareous grasslands in sub-Mediterranean Slovenia. Our goal was to set the basis for a long-term monitoring of this butterfly in four meadows using mark-release-recapture (MRR). We determined its demographic parameters, dispersal, behaviour and utilization of nectar plants in different quality patches. Total population size was estimated to be approximately 347 males (95% confidence interval: 262-432) and 326 females (95% confidence interval: 250-402), with an unbiased sex ratio. The average lifespans were 6.3 and 8.6 days, respectively. Daily population sizes followed a parabola with marked protandry. Both sexes were relatively highly mobile with both occasionally moving over half a kilometre. The spatial distribution of animals seemed to be associated with patch size, host plant densities and nectar sources, resulting in much higher population densities in the largest patch. Adult behaviour differed between the sexes, with females resting more and flying less than males. Behaviour also changed during daytime and with the progression of the season. Adults were confirmed to be opportunistic feeders, since as many as ten nectar sources were detected. We conclude that demographic parameters differ greatly among regions and habitats, thus conservation aims should be planned accordingly. Although the population studied is apparently in good condition, there are threats that may hamper the long-term persistence of the species in this area: succession, intensification of mowing and overgrazing. |
First record of Azalea rough bollworm, Earias roseifera (Lepidoptera: Nolidae) in EuropeNoteAndrea TADDEI, Andrea TANTARDINI, Keitaro EDAEur. J. Entomol. 116: 235-239, 2019 | DOI: 10.14411/eje.2019.026 The first record of the Azalea rough bollworm, Earias roseifera Butler, 1881 in Europe is reported. Larvae were collected on twigs, sprouts and buds of several azalea hybrids growing in a botanical garden in the province of Como (Northern Italy). The larvae fed mainly on the flower and vegetative buds, which resulted in a significant reduction in the amount of blossom. Specimens were identified using both morphological characters and a molecular analysis of the DNA barcode (COX1 sequence). |
The parasitoid species complex associated with sexual and parthenogenetic Naryciinae (Lepidoptera: Psychidae): Integrating ecological and molecular analysesJelmer A. ELZINGA, Kees ZWAKHALS, Johanna MAPPES, Alessandro GRAPPUTOEur. J. Entomol. 108 (4): 635-650, 2011 | DOI: 10.14411/eje.2011.082 This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupicollella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A DNA barcoding technique was employed to identify host species from parasitized larval remains. By sampling more than 10,000 host larvae, of which 25.7% were parasitized, nine parasitoid species were identified morphologically, including both koinobionts (Ichneumonidae: Diadegma incompletum, Macrus parvulus, Trachyarus borealis, T. solyanikovi, T. fuscipes, T. brevipennis and Braconidae: Meteorus affinis) and idiobionts (Ichneumonidae: Orthizema flavicorne, Gelis fuscicornis). Ecological characteristics such as time and mode of host attack, time of emergence and level of specialization differed widely. The results show that differences in parasitoid biology need to be taken into account when studying differences in percentage parasitism of sexual and parthenogenetic Naryciinae. The molecular data revealed that one parasitoid species M. parvulus may consist of two cryptic forms associated with the sexual and parthenogenetic hosts, respectively. The data further establishes that T. brevipennis and some T. fuscipes are in fact morphotypes of one species. The large variation in mitochondrial DNA within species and its inconsistency with nuclear DNA demonstrate that current species and genus delimitation is inadequate in the Trachyarus species group. Our study shows that it is essential to use DNA barcoding methods when investigating host-parasitoid complexes. |
A review of taxonomy and flower-breeding ecology of the Colocasiomyia toshiokai species group (Diptera: Drosophilidae), with description of a new species from IndonesiaOriginal articleTao SHI, Masanori J. TODA, Kohei Takenaka TAKANO, Masako YAFUSO, Awit SUWITO, Sin Yeng WONG, Su-Qin SHANG, Jian-Jun GAOEur. J. Entomol. 116: 341-361, 2019 | DOI: 10.14411/eje.2019.037 Flies of the Colocasiomyia toshiokai species group depend exclusively on inflorescences/infructescences of the aroid tribe Homalomeneae. The taxonomy and reproductive biology of this group is reviewed on the basis of data and samples collected from Southeast Asia. The species boundaries are determined by combining morphological analyses and molecular species delimitation based on sequences of the mitochondrial COI (cytochrome c oxidase subunit I) gene. For the phylogenetic classification within this species group, a cladistic analysis of all the member species is conducted based on 29 parsimony-informative, morphological characters. As a result, six species are recognised within the toshiokai group, including one new species, viz. C. toshiokai, C. xanthogaster, C. nigricauda, C. erythrocephala, C. heterodonta and C. rostrata sp. n. Various host plants are utilised by these species in different combinations at different localities: Some host plants are monopolized by a single species, while others are shared by two or three species. C. xanthogaster and C. heterodonta cohabit on the same host plant in West Java, breeding on spatially different parts of the spadix. There is a close synchrony between flower-visiting behaviour of flies and flowering events of host plants, which indicate an intimate pollination mutualism. |
First mitogenome for the tribe Saccharosydnini (Hemiptera: Delphacidae: Delphacinae) and the phylogeny of three predominant rice planthoppersOriginal articleYi-Xin HUANG, Dao-Zheng QINEur. J. Entomol. 115: 242, 2018 | DOI: 10.14411/eje.2018.023 The mitochondrial genome of Saccharosydne procerus (Matsumura) is the first sequenced in the tribe Saccharosydnini (Hemiptera: Delphacidae: Delphacinae). In addition, the mitogenome sequence of Sogatella vibix (Haupt) (in Delphacini) is also sequenced. The Sa. procerus mitochondrial genome is 16,031 bp (GenBank accession no. MG515237) in length, and So. vibix is 16,554 bp (GenBank accession no. MG515238). The existence of purifying selection was indicated by the rate of nonsynonymous and synonymous substitutions. Three species of Delphacini, Laodelphax striatellus (Fallén), Sogatella furcifera (Horváth) and Nilaparvata lugens (Stål), are important pests of rice. The phylogeny of these three rice planthoppers based on the mitochondrial genome sequence was (L. striatellus + (So. vibix + So. furcifera)) + (N. muiri + N. lugens). |
Discovery of a remarkable new species of Lymanopoda (Lepidoptera: Nymphalidae: Satyrinae) and considerations of its phylogenetic position: An integrative taxonomic approachOriginal articleTomasz W. PYRCZ, Carlos PRIETO, Pierre BOYER, Jadwiga LORENC-BRUDECKAEur. J. Entomol. 115: 387-399, 2018 | DOI: 10.14411/eje.2018.039 A new species of Lymanopoda Westwood, a cloud forest Neotropical genus of Satyrinae, is described from the páramo grasslands on an isolated, peripheral massif in the Colombian Central Cordillera of the Andes: L. flammigera Pyrcz, Prieto & Boyer, sp. n. The genus Lymanopoda is species-rich (approx. 65 species) and its alpha taxonomy is relatively well researched. Relationships within the genus using molecular data have also been explored. The new species is outstanding for its golden yellow colour in males, not found in any other neotropical Satyrinae. Cladograms were constructed based on COI sequences of 47 species of Lymanopoda (~ 70% of the known species) including 17 from Colombia. The new species segregates in the "tolima" clade, which comprises four other high altitude Colombian species, as well as two from Ecuador. However, it is the comparative analysis of male genitalia, in particular the superuncus and valvae, which identified its closest relatives, thus confirming that genital characters can help refine molecular phylogenies. In addition to identifying species using mitochondrial DNA (mtDNA barcodes), nucleotide sites with unique fixed states used to identify nine species of Lymanopoda from Colombia are also presented. |
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. |
Tracing imprints of past climatic fluctuations and heterogeneous topography in Cynips quercusfolii (Hymenoptera: Cynipidae) in TurkeyOriginal articleSerdar DİNÇ, Serap MUTUNEur. J. Entomol. 116: 141-157, 2019 | DOI: 10.14411/eje.2019.016 Cynips quercusfolii is an oak gall wasp species distributed across the western Palearctic region. In this study, C. quercusfolii adults were used to investigate the possible effects of past climatic fluctuations and topography on the genetic structure of this species in Turkey. For this, the partial mitochondrial DNA (mtDNA) cytochrome b gene (cyt b) and nuclear DNA (nDNA) ITS2 region of 294 individuals from 38 populations covering the distribution of this species in Turkey were sequenced. The sequences generated 125 mtDNA haplotypes and 30 nDNA alleles. High variation was revealed in Turkish populations of C. quercusfolii (h = 0.7328 and π = 0.0102 for cyt b, and h = 0.5865 and π = 0.0058 for ITS2). Demographic analyses and high haplotype versus low nucleotide diversity indicated that C. quercusfolii populations might have undergone a series of expansions and contractions in the past. Phylogenetic analyses showed that this species is structured geographically between east and west due to a major physical barrier, the Anatolian Diagonal. Furthermore, divergence times of the lineages implied that deep splits occurred before the Pleistocene, while intermediate to shallow splits were associated with climatic changes during the Pleistocene. We conclude that ongoing geological events and associated climatic cycles were responsible for the current population genetic structure of this species in Turkey. |
Fungi associated with Ips acuminatus (Coleoptera: Curculionidae) in Ukraine with a special emphasis on pathogenicity of ophiostomatoid speciesOriginal articleKateryna DAVYDENKO, Rimvydas VASAITIS, Audrius MENKISEur. J. Entomol. 114: 77-85, 2017 | DOI: 10.14411/eje.2017.011 Conifer bark beetles are well known to be associated with fungal complexes, which consist of pathogenic ophiostomatoid fungi as well as obligate saprotroph species. However, there is little information on fungi associated with Ips acuminatus in central and eastern Europe. The aim of the study was to investigate the composition of the fungal communities associated with the pine engraver beetle, I. acuminatus, in the forest-steppe zone in Ukraine and to evaluate the pathogenicity of six associated ophiostomatoid species by inoculating three-year-old Scots pine seedlings with these fungi. In total, 384 adult beetles were collected from under the bark of declining and dead Scots pine trees at two different sites. Fungal culturing from 192 beetles resulted in 447 cultures and direct sequencing of ITS rRNA from 192 beetles in 496 high-quality sequences. Identification of the above revealed that the overall fungal community was composed of 60 species. Among these, the most common were Entomocorticium sp. (24.5%), Diplodia pinea (24.0%), Ophiostoma ips (16.7%), Sydowia polyspora (15.1%), Graphilbum cf rectangulosporium (15.1%), Ophiostoma minus (13.8%) and Cladosporium pini-ponderosae (13.0%). Pathogenicity tests were done using six species of ophiostomatoid fungi, which were inoculated into Scots pine seedlings. All ophiostomatoid fungi tested successfully infected seedlings of Scots pine with varying degrees of virulence. Ophiostoma minus was the only fungus that caused dieback in inoculated seedlings. It is concluded that I. acuminatus vectors a species-rich fungal community including pathogens such as D. pinea and O. minus. The fungal community reported in the present study is different from that reported in other regions of Europe. Pathogenicity tests showed that O. minus was the most virulent causing dieback in seedlings of Scots pine, while other fungi tested appeared to be only slightly pathogenic or completely non-pathogenic. |
Cold hardiness of larvae of Dendrolimus tabulaeformis (Lepidoptera: Lasiocampidae) at different stages during the overwintering periodOriginal articleYuying SHAO, Yuqian FENG, Bin TIAN, Tao WANG, Yinghao HE, Shixiang ZONGEur. J. Entomol. 115: 198-207, 2018 | DOI: 10.14411/eje.2018.018 The Chinese pine caterpillar Dendrolimus tabulaeformis is an important destructive leaf borer in boreal coniferous forests in China. This species overwinters in the larval stage. Changes in supercooling capacity and physiological-biochemical parameters of D. tabulaeformis larvae from a natural population were evaluated at different stages during the overwintering period. Cold hardiness of overwintering larvae collected in January was significantly greater than that of larvae collected in other months. January larvae survived for 15 days at -10°C and for approximately 2 days at -15°C. By contrast, larvae collected in September survived for no more than 4 h at -5°C and those in November and March no more than 1 day at -15°C. Supercooling point gradually decreased from -5.9 ± 0.3°C in September to a minimum of -14.1 ± 1.0°C in November, then gradually increased to the original value with the advent of spring. Water content gradually decreased from September to November, remained at approximately 74.5% until March and then gradually increased to levels similar to those in September. The lipid content gradually decreased from September to November, remained stable at approximately 3.2% until March and then gradually increased to levels similar to those in September. Glycogen content increased to a peak in November and then decreased. The concentrations of several metabolites showed significant seasonal changes. The most prominent metabolite was trehalose with a seasonal maximum in November. Glucose levels were highest in January and then gradually decreased until in May they were at levels similar to those in September. Glycerol levels remained relatively stable during winter but increased significantly in May. This study indicates that D. tabulaeformis is a freeze-avoidant insect. Larvae increase their supercooling capacity by regulating physiological-biochemical parameters during overwintering. Our results provide the basis for further research into the mechanism of cold hardiness in this species. |
Does Hartigiola annulipes (Diptera: Cecidomyiidae) distribute its galls randomly?Original articleSebastian PILICHOWSKI, Marian J. GIERTYCHEur. J. Entomol. 115: 504-511, 2018 | DOI: 10.14411/eje.2018.050 It is expected that environmental conditions impact the distribution of galls on host plants. Moreover, insects may induce their galls randomly or choose certain parts of a host to induce such growths. This study aimed to determine whether or not the gall midge, Hartigiola annulipes (Diptera: Cecidomyiidae), which induces galls on leaves of the European beech (Fagus sylvatica), prefers leaves facing a particular cardinal direction. In addition, we wanted to ascertain whether the galls are evenly spread across three leaf zones: proximal, median and distal, distinguished by dividing leaf area along the midrib. The results show that H. annulipes chose leaves facing various directions in different studied locations, and leaf choice is not restricted to the specific leaf area, a parameter that accurately reflects the light conditions of leaf growth. Moreover, the medial leaf zone was preferred, while the distal zone was avoided. The choice of the leaf zone modified the distance between the mid-rib and a gall. Gall distribution in the crown of trees is probably random, while at the leaf level, it is determined by leaf morphology. |
Factors determining local and seasonal variation in abundance of Harmonia axyridis (Coleoptera: Coccinellidae) in Central EuropeOriginal articleAlois HONĚK, Marek BRABEC, Zdenka MARTINKOVÁ, Anthony F.G. DIXON, Stano PEKÁR, Jiří SKUHROVECEur. J. Entomol. 116: 93-103, 2019 | DOI: 10.14411/eje.2019.011 To determine the causes of the variation in the seasonal dynamics of Harmonia axyridis (Pallas) in Central Europe, numbers of adults and larvae of this invasive species were recorded on trees (Acer, Betula, Tilia) throughout the growing seasons from 2011 to 2016. Each year beetles were collected every two weeks, using a standardized sweeping method. The seasonal dynamics was expressed as plots of abundance (number of individuals per 100 sweeps) against time (Julian day) and these plots (seasonal profiles) were compared in terms of their size (area under the seasonal profile curve), range, timing and height of the mode (maximum abundance). Timing and size of seasonal profiles varied among hostplants, years and sites. Abundance of larvae paralleled aphid occurrence and peak abundance of adults followed that of larvae 10 to 20 days later. Population dynamics before and after the peak were determined by dispersal. Adults arrived at sites before the start of aphid population growth and persisted there long after aphid populations collapsed. The abundance of H. axyridis decreased from 2011 to 2013 and then increased, achieving the previous levels recorded in 2015 and 2016. The variation in seasonal profiles revealed that H. axyridis, in terms of its response to environmental conditions, is a plastic species and this flexibility is an important factor in its invasive success. |
Yellow does not improve the efficiency of traps for capturing wasps of the genera Vespula and Dolichovespula (Hymenoptera: Vespidae)Original articleJouni SORVARIEur. J. Entomol. 116: 240-243, 2019 | DOI: 10.14411/eje.2019.027 Social wasps are often considered as nuisance pests in urban environments and are often controlled by using traps. The majority of commercially produced traps for catching wasps have yellow as the dominant colour around the trap entrance. However, the observations on the function of yellow as an attractant for wasps are controversial. The efficiency of yellow, compared with green striped (N = 15) and yellow and green striped beer traps (N = 15) was evaluated. According to the results, yellow does not have a specific role as an attractant for wasps of the genera Vespula Linnaeus and Dolichovespula (Rohwer). For wasps, it may be the bait that is the major lure and it might be sufficient on its own for both control and monitoring purposes. |
Detailed morphological descriptions of the immature stages of the ant parasite Microdon mutabilis (Diptera: Syrphidae: Microdontinae) and a discussion of its functional morphology, behaviour and host specificityOriginal articleGiulia SCARPARO, Pierfilippo CERRETTI, Maurizio MEI, Andrea DI GIULIOEur. J. Entomol. 114: 565-586, 2017 | DOI: 10.14411/eje.2017.071 The myrmecophilous immature stages of hover flies of the genus Microdon Meigen, 1803 (Diptera, Syrphidae) are still poorly known and only about 15 species were previously incompletely described and/or illustrated using light microscopy based on occasional findings mainly of pupae and third instar larvae. The exceptional finding of a large number of second and third instar larvae and pupae (159 specimens) of Microdon mutabilis (Linnaeus, 1758) inside the nest of a new host species, Formica cunicularia Latreille,1798, enabled us to rear them and obtain a great number of eggs and first instar larvae. We filmed and described the feeding behaviour and locomotion of these highly derived slug-like larvae. Combining light, fluorescence and scanning electron (SEM) microscopy, we describe in detail and illustrate the external features of all the immature stages of M. mutabilis (eggs, larvae and pupae). Covering the entire chorion of the egg is a peculiar microsculpture composed of volcano-like processes. The three larval instars strongly differ from each other, especially at the level of the shape of the body, the posterior spiracular tubercle and the cephaloskeleton. SEM microscopy was used to describe in detail the microsculpture, sensorial structures, spiracles and cephalic appendages of larvae and pupae. Fluorescence microscopy was used to reveal the exceptional presence of resilin in the external layer of the posterior spiracular tubercle in first instar larvae. The possible functional significance of these structures is discussed. |
Influence of urbanisation and plants on the diversity and abundance of aphids and their ladybird and hoverfly predators in domestic gardensOriginal articleElise A. ROCHA, Estevão N.F. SOUZA, Lewis A.D. BLEAKLEY, Christopher BURLEY, Jade L. MOTT, Gloria RUE-GLUTTING, Mark D.E. FELLOWESEur. J. Entomol. 115: 140-149, 2018 | DOI: 10.14411/eje.2018.013 Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Hemiptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverflies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfly species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may reflect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators. |
Phenotypic pattern over centric fusion clinal variation in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)Original articlePablo C. COLOMBO, María I. REMISEur. J. Entomol. 115: 303-311, 2018 | DOI: 10.14411/eje.2018.029 The water-hyacinth grasshopper, Cornops aquaticum, occurs in freshwater environments in the New World between latitudes 23°N and 35°S. At the southernmost margin of this distribution the populations are polymorphic for three centric fusions (Robertsonian translocations). The frequencies of these chromosome rearrangements increase southwards and the recombination in structural homozygotes and heterozygotes diminishes both along the middle and lower courses of the Paraná River. In the present paper we report a similar cline along the southward flowing Uruguay River. In addition, we report the morphological effects of two of these centric fusion polymorphisms, namely the fusions between chromosomes 2 and 5 of the standard complement (fusion 2/5) and chromosomes 3 and 4 (fusion 3/4) and extend this study to the Uruguay River. There is a strong inverse correlation of fusion frequency with temperature, which indicates that these polymorphisms may be related to increased tolerance of colder climates in this originally tropical species, or some other correlated variable. This study is a further example of chromosomal clines correlated with latitude and is one of a few examples of chromosome polymorphisms associated with phenotypic effects. Finally, it indicates ways of using this species for controlling pests. |
Weather-dependent fluctuations in the abundance of the oak processionary moth, Thaumetopoea processionea (Lepidoptera: Notodontidae)Original articleGyörgy CSÓKA, Anikó HIRKA, Levente SZŐCS, Norbert MÓRICZ, Ervin RASZTOVITS, Zoltán PÖDÖREur. J. Entomol. 115: 249-255, 2018 | DOI: 10.14411/eje.2018.024 Population fluctuations of the well-known oak defoliator, the oak processionary moth (Thaumetopoea processionea L.), were studied using light trap data and basic meteorological parameters (monthly average temperatures, and precipitation) at three locations in Western Hungary over a period of 15 years (1988-2012). The fluctuations in the numbers caught by the three traps were strongly synchronized. One possible explanation for this synchrony may be similar weather at the three trapping locations. Cyclic Reverse Moving Interval Techniques (CReMIT) were used to define the period of time in a year that most strongly influences the catches. For this period, we defined a species specific aridity index for Thaumetopoea processionea (THAU-index). This index explains 54.8-68.9% of the variation in the yearly catches, which indicates that aridity, particularly in the May-July period was the major determinant of population fluctuations. Our results predict an increasing future risk of Oak Processionary Moth (OPM) outbreaks and further spread if the frequency of severe spring/summer droughts increases with global warming. |
Effects of temperature on the activity of antioxidant enzymes in larvae of Bactrocera dorsalis (Diptera: Tephritidae) parasitized by Diachasmimorpha longicaudata (Hymenoptera: Braconidae): Optimizing the mass rearing of this braconid by varying the temperatureOriginal articlePumo CAI, Yong WANG, Chuandong YI, Qiwen ZHANG, Huimin XIA, Jia LIN, Hehe ZHANG, Jianquan YANG, Qinge JI, Jiahua CHENEur. J. Entomol. 116: 1-9, 2019 | DOI: 10.14411/eje.2019.001 Diachasmimorpha longicaudata is the most widely used endoparasitoid in biocontrol programmes against various species of tephritids and is continuously mass-reared under laboratory conditions at a constant temperature; however, little is known about how varying the temperature might affect the effectiveness of the mass rearing of immature D. longicaudata. This study aimed to determine the optimum temperature for the development of larvae D. longicaudata the larvae of its host, Bactrocera dorsalis. Third-instar B. dorsalis were exposed for 4 h to five pairs of parasitoids, and then they were kept at one of six temperatures ranging from 19°C to 34°C. The activities of three major antioxidant enzymes (CAT, POX, SOD) were individually measured 4, 24, 48 and 72 h after exposure to each of the six temperatures. The results were as follows: for CAT the highest CAT activities were recorded at 25°C (intervals 5-24 h and 25-48 h), at 28°C (interval 0-4 h) and at 31°C (interval 49-72 h), and for POX and SOD identically at 25°C (intervals 0-4 h, 5-24 h) and at 31°C (intervals 25-48 h, 49-72 h), respectively. Subsequently, the effects keeping the parasitized larvae at these different temperatures on the biological attributes of D. longicaudata reared under laboratory conditions were investigated. The percentage of their eggs that hatched, percentage of adults that emerged, pupal weight and longevity were significantly greater than that recorded for the control when the parasitized host larvae were kept at 28°C for 4 h, 25°C for 5 and 48 h and 31°C for 49 and 72 h. |
Circadian rhythms in the locomotor activity of the spiders Carrhotus xanthogramma (Salticidae) and Philodromus cespitum (Philodromidae): Temporal patterns and sexual differencesOriginal articleLászló MEZŐFI, Gábor MARKÓ, Péter KOVÁCS, Viktor MARKÓEur. J. Entomol. 116: 158-172, 2019 | DOI: 10.14411/eje.2019.017 Circadian rhythms play an essential role in the adaptation of organisms to the environment and may show species-specific or sex-specific differences even within a closely related taxonomic group. Although spiders (Araneae) are sexually dimorphic in several morphological and behavioural features, there are very few studies on the sex-specific differences in their biological rhythms. This study evaluated the circadian rhythm in the locomotor activity of two agrobiont hunting species of spider, Carrhotus xanthogramma (Latreille, 1819) (Salticidae) and Philodromus cespitum (Walckenaer, 1802) (Philodromidae), under natural photoperiod conditions. Particular attention was paid to possible differences between the sexes in both species. We found that C. xanthogramma is a strictly diurnal species with a mean activity peak in the morning in both sexes and the females are more active than males. The locomotor activity rhythm of males was richer in ultradian (shorter than a day but longer than an hour) components, although the relative power of these components was negligible compared to the main, 24-h period component. In accordance with these results, the diel pattern of locomotor activity of C. xanthogramma can be described by a unimodal cosine curve. In contrast to C. xanthogramma, both sexes of Ph. cespitum showed cathemeral activity (i.e., activity occur within both the light and dark portions of the daily cycle) and females and males follow quite different activity schedules: females were most active at night, shortly before nautical dawn, whereas males were most active early in the morning. Unlike C. xanthogramma, Ph. cespitum has more ultradian components, with higher relative power especially in females, where besides the 24-h circadian component there is a particularly strong 12-h ultradian period. Based on these factors, females of Ph. cespitum show a bimodal and males a unimodal pattern. |
The effects of oviposition site on the development of the wood borer Coraebus florentinus (Coleoptera: Buprestidae)Ana M. CÁRDENAS, Patricia GALLARDOEur. J. Entomol. 110 (1): 135-144, 2013 | DOI: 10.14411/eje.2013.019 Coraebus florentinus (Herbst) is one of the most important wood borer pests of oaks in forest ecosystems in the Mediterranean Region. It is considered to be a heliophilous species as it prefers the sunniest parts of the canopy of isolated trees. The biological significance of this preference is still unknown. Recently, the effect of temperature on the preimaginal development of this insect was established: high temperatures increase its probability of survival and shorten its developmental time. Continuing this line of research, this study was designed to determine whether C. florentinus exhibits selective oviposition behaviour and how variation in temperature due to differences in the position of the branches in which the larvae develop could affect the subsequent development of this species. To determine whether this insect selects the branches in which to lay its eggs, location data (north, south, upper half and lower half of the tops of the trees) for 112 damaged branches were analysed. The results confirm that females of C. florentinus do not lay their eggs at random at the tops of trees but rather choose branches that are exposed to the sun. To determine the effects of larval rearing temperature on the later development stages, an experiment consisting of five treatments was performed. Four of these treatments, each containing 25 infested branches derived from different orientations and positions in a tree (upper half of tree and north facing, upper half and south facing, lower half and north facing and lower half and south facing) were kept in culture chambers maintained at optimal conditions for pupal development (28 ± 2°C and 60-65% relative humidity). The fifth treatment with 25 branches infested collected from the most sun-exposed locations were kept in outdoor conditions. The results indicate that variation in temperature during larval development due to differences in branch location does not significantly affect survival, duration of developmental of pupae, emergence success or sex ratio of the adults. |