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Results 511 to 540 of 825:

A gut-specific chitinase from the mulberry longicorn beetle, Apriona germari (Coleoptera: Cerambycidae): cDNA cloning, gene structure, expression and enzymatic activity

Young Moo CHOO, Kwang Sik LEE, Bo Yeon KIM, Doh Hoon KIM, Hyung Joo YOON, Hung Dae SOHN, Byung Rae JIN

Eur. J. Entomol. 104 (2): 173-180, 2007 | DOI: 10.14411/eje.2007.026

A gut-specific chitinase gene was cloned from the mulberry longicorn beetle, Apriona germari. The A. germari chitinase (AgChi) gene spans 2894 bp and consists of five introns and six exons coding for 390 amino acid residues. AgChi possesses the chitinase family 18 active site signature and three N-glycosylation sites. Southern blot analysis of genomic DNA suggests that AgChi is a single copy gene. The AgChi cDNA was expressed as a 46-kDa polypeptide in baculovirus-infected insect Sf9 cells and the recombinant AgChi showed activity in a chitinase enzyme assay. Treatment of recombinant virus-infected Sf9 cells with tunicamycin, a specific inhibitor of N-linked glycosylation, revealed that AgChi is N-glycosylated, but the carbohydrate moieties are not essential for chitinolytic activity. Northern and Western blot analyses showed that AgChi was specifically expressed in the gut; AgChi was expressed in three gut regions, indicating that the gut is the prime site for AgChi synthesis in A. germari larvae.

Density dependence of the alarm pheromone effect in pea aphids, Acyrthosiphon pisum (Sternorrhyncha: Aphididae)

Grit KUNERT, Janett TRAUTSCH, Wolfgang W. WEISSER

Eur. J. Entomol. 104 (1): 47-50, 2007 | DOI: 10.14411/eje.2007.007

The aphid alarm pheromone is known to trigger wing induction in pea aphids (Acyrthosiphon pisum). In reaction to alarm pheromone, aphids drop off the plant or walk away. While searching for a new feeding site they repeatedly encounter other members of the aphid colony and this increased contact rate is assumed to be important for wing induction ("pseudo-crowding" hypothesis). Because the encounter rate is a function of aphid colony size, wing induction in aphids in the presence of a predator should be a function of the number of aphids on the plant. We placed two, seven or 13 adult pea aphids on bean plants, and exposed the different-sized colonies to synthetic alarm pheromone to test the density-dependence of predator-induced wing induction. The mean percentage of winged morphs among the offspring produced on the plants ranged from 10 to 80 percent and increased both with aphid number and exposure to alarm pheromone. There was no synergy between aphid number and alarm pheromone exposure indicating that both factors are additive. The implications for aphid metapopulation dynamics are discussed.

Increased migration of Lepidoptera linked to climate change

Tim H. SPARKS, Roger L.H. DENNIS, Philip J. CROXTON, Martin CADE

Eur. J. Entomol. 104 (1): 139-143, 2007 | DOI: 10.14411/eje.2007.019

The number of species of migratory Lepidoptera (moths and butterflies) reported each year at a site in the south of the UK has been rising steadily. This number is very strongly linked to rising temperatures in SW Europe. It is anticipated that further climate warming within Europe will increase the numbers of migratory Lepidoptera reaching the UK and the consequences of this invasion need urgent attention.

Oviposition-deterring effects of conspecific and heterospecific larval tracks on Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

Zdeněk RŮ®IČKA

Eur. J. Entomol. 103 (4): 757-763, 2006 | DOI: 10.14411/eje.2006.101

The oviposition deterring effects of fresh larval tracks of Cheilomenes sexmaculata (F.), Ceratomegilla undecimnotata (Schneider), Cycloneda limbifer Casey, and Harmonia dimidiata (F.) on C. sexmaculata females were compared in standard laboratory choice tests. Moreover, the persistence of intraspecific effects of C. sexmaculata larval tracks were investigated. Fresh tracks of C. sexmaculata, C. limbifer and C. undecimnotata larvae effectively deterred C. sexmaculata females from ovipositing. The effect of fresh larval tracks of H. dimidiata was not statistically significant. The oviposition-deterring effects of 10 d-old conspecific larval tracks were considerably lower than those of fresh tracks, but remained significant. Clutch sizes were smaller in the blank test without larval tracks than in choice tests with fresh tracks of conspecific, C. limbifer, C. undecimnotata, H. dimidiata larvae and with 10 d-old tracks of conspecific larvae. The study indicates that semiochemicals in the tracks of conspecific and heterospecific coccinellid larvae can contribute considerably to the spacing of C. sexmaculata offspring among prey resources of differing quality and that conspecific as well as heterospecific larval tracks can influence clutch size.

Pre-diapause mating and overwintering of fertilized adult females: New aspects of the life cycle of the wing-polymorphic bug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

Radomír SOCHA

Eur. J. Entomol. 107 (4): 521-525, 2010 | DOI: 10.14411/eje.2010.059

New aspects of the life-cycle of the flightless wing-polymorphic bug Pyrrhocoris apterus (L.) are described. It was found that 1.1-14.9% of the adult females of P. apterus in 11 samples collected from 4 populations in the South Bohemia had mated prior to entering diapause and their ovaries were in the pre-vitellogenic stage of development with viable sperm in their spermathecae. Some of these females successfully overwintered. The percentage of overwintering females that had been fertilized ranged from 1.1 to 7.2 % and depended on the month and year of collection. The results indicate that pre-diapause mating and overwintering of fertilized females is not unusual in populations of P. apterus in the Czech Republic and and that sperm in overwintering female survives for at least 7-8 months.

Distribution, abundance and host association of two parasitoid species attacking frugivorous drosophilid larvae in central Japan

Hideyuki MITSUI, Masahito T. KIMURA

Eur. J. Entomol. 107 (4): 535-540, 2010 | DOI: 10.14411/eje.2010.061

In central Japan Ganaspis xanthopoda and Asobara japonica commonly parasitize the larvae of frugivorous drosophilids, mainly in montane forests, and urban environments and small groves, respectively. These two parasitoids start reproduction about one month later than their host drosophilids, probably to avoid searching for hosts when host density is low in early spring. It is likely that the local variation in the abundance of these parasitoids and a temporal refuge for their hosts contribute to the persistence of this parasitoid-host community. The forest species, G. xanthopoda, parasitized at least three Drosophila species that are abundant in forests, supporting the hypothesis that parasitoids are better adapted to attack frequently-encountered host species. This parasitoid did not parasitize drosophilid species that are phylogenetically distantly-related to the three host species or less frequent in forests. Benefits of using such species as host would not exceed the costs of evolving virulence to them. Another parasitoid, A. japonica, parasitized various indigenous and exotic drosophilid species including those that it rarely encountered in the field. It is not clear why this species has such a wide host range.

Effect of population density on the development of Mesovelia furcata (Mesoveliidae), Microvelia reticulata and Velia caprai (Veliidae) (Heteroptera: Gerromorpha)

Tomáą DITRICH, Miroslav PAPÁČEK

Eur. J. Entomol. 107 (4): 579-587, 2010 | DOI: 10.14411/eje.2010.067

Population density during nymphal development affects body size, developmental rate and wing polymorphism in semiaquatic bugs. Nymphs from crowded habitats grow faster and thus gain an advantage in the later stadia. Rapid development results in smaller body size in several gerrids. Macropterous adults develop more frequently at high population densities in most species, which enables the bugs to leave crowded habitats. Three European widespread species Mesovelia furcata Mulsant & Rey, 1852 (Mesoveliidae), Microvelia reticulata Burmeister, 1835 and Velia caprai Tamanini, 1947 (Veliidae) were reared individually and simultaneously either at a low or high population density. Duration of postembryonic development, wing morph, body size and length of distal oocyte in females were recorded. High population density accelerates development in Mesovelia furcata and Microvelia reticulata. However, there was no trade-off between developmental rate and body size. Accelerated development without a decrease in body size was probably because maturation was delayed. Individually reared nymphs developed faster than nymphs from communal cohorts. No long-winged Microvelia reticulata specimen developed in any treatment. However, more macropterous individuals developed in high-density treatments in Mesovelia furcata (significant) and Velia caprai (not significant). All the nymphs of the species that were reared individually developed into apterous adults. The results suggest that population density strongly influences the life history of semiaquatic bugs. However, the only commonly shared response seems to be an increase in developmental rate when reared at high population densities. Other traits such as wing dimorphism, body size and rate of oogenesis differ at the species level.

Temperature-dependent development of dubas bug, Ommatissus lybicus (Hemiptera: Tropiduchidae), an endemic pest of date palm, Phoenix dactylifera

Abdul Monim MOKHTAR, Salem Saif Al NABHANI

Eur. J. Entomol. 107 (4): 681-685, 2010 | DOI: 10.14411/eje.2010.076

Dubas bug, Ommatissus lybicus Bergevin, is an important pest of date palm on the Arab peninsula. This sucking insect causes great damage to the trees and reduces the quantity and quality of the dates. Effect of temperature on the development of the immature stages of O. lybicus was studied in the laboratory by rearing them at nine constant temperatures, ranging from 15 to 35°C. Development was successfully completed at temperatures ranging from 20 to 35°C for eggs and from 20 to 32.5°C for nymphs. The lower thermal thresholds for development of eggs, nymphs and egg-adult were estimated by means of linear regression as 12.9, 12.9 and 13.2°C, respectively. Thermal units required for the development of the same stages were 572.5, 648.2 and 1184.4 degree-days, respectively. The lethal high temperatures were also estimated using a nonlinear model as 34.5, 43.4 and 34.6°C for eggs, nymphs and total immature stages, respectively. The development rate and survival data indicate that the optimum temperature range for O. lybicus is 25-27.5°C.

The effect of host plant and isolation on the genetic structure of phytophagous insects: A preliminary study on a bruchid beetle

Gwendal RESTOUX, Martine HOSSAERT-MCKEY, Betty BENREY, Nadir ALVAREZ

Eur. J. Entomol. 107 (3): 299-304, 2010 | DOI: 10.14411/eje.2010.038

Genetic differentiation is a consequence of the combination of drift and restriction in gene flow between populations due to barriers to dispersal, or selection against individuals resulting from inter-population matings. In phytophagous insects, local adaptation to different kinds of host plants can sometimes lead to reproductive isolation and thus to genetic structuring, or even to speciation. Acanthoscelides obtectus Say is a bean bruchid specialized on beans of the Phaseolus vulgaris group, attacking both wild and domesticated forms of P. vulgaris and P. coccineus. This study reveals that the genetic structure of populations of this bruchid is explained mainly by their geographical location and is not related to a particular kind (wild or domesticated) of bean. In contrast, the species of bean might have led, to some extent, to genetic structuring in these bruchids, although our sampling is too limited to address such process unambiguously. If confirmed, it would corroborate preliminary results found for the parasitoid species that attack Acanthoscelides species, which might show a genetic structure depending on the species of host plant.

Genetic structure and phenotypic diversity of two northern populations of Cheilosia aff. longula (Diptera: Syrphidae) has implications for evolution and conservation

Vesna MILANKOV, Ljubinka FRANCUSKI, Jasmina LUDO©KI, Gunilla STÅHLS, Ante VUJIĆ

Eur. J. Entomol. 107 (3): 305-315, 2010 | DOI: 10.14411/eje.2010.039

The genetic structure and phenotypic diversity of two populations of Cheilosia aff. longula (Diptera: Syrphidae) in Lapland, Finland, were examined using DNA sequencing, protein electrophoresis, and geometric morphometrics. The morphological identification of the species were verified using partial sequences of mitochondrial cytochrome c oxidase subunit I (COI mtDNA), and the nuclear ribosomal internal transcribed region 2 (ITS2 rDNA), and comparing the corresponding sequences of Cheilosia aff. longula and the closely related C. longula. Two and three haplotypes of the genes COI mtDNA and ITS2 rDNA were identified in the two populations. Analysis of 12 isozyme loci showed an extremely low genetic variability in the populations originating from Utsjoki and Kevo. Discriminant analysis combined with canonical variate analysis revealed inter-population divergence in wing shape. Variation among genetically diverse individuals, both within- and among studied populations was studied, and directional (DA) and fluctuating asymmetry (FA) estimated using landmarks in the framework of geometric morphometrics. It is likely that the documented DA and FA asymmetry in both wing shape and size reflects the developmental instability of the individuals studied. By using Procrustes ANOVA the locations of particular landmarks responsible for the variation in shape were determined. The decomposition of the components of variance accorded to each landmark showed that the landmarks differed in the percentage of variation they accounted for (DA, FA and variation among individuals). In the discussion the implications of the reduced genetic diversity and asymmetry in wing traits for conservation is considered.

Weather factors affecting the male mate-locating tactics of the small copper butterfly (Lepidoptera: Lycaenidae)

Jun-Ya IDE

Eur. J. Entomol. 107 (3): 369-376, 2010 | DOI: 10.14411/eje.2010.046

Males of the small copper butterfly, Lycaena phlaeas daimio, exhibit two mate-locating tactics: patrolling and perching. Field investigations were conducted to determine the biotic and abiotic factors affecting the mate-locating behaviour of male L. phlaeas. Patrolling was often observed when light intensity was high. Perching was performed throughout the day regardless of environmental conditions, but the chasing of passing insects increased at high light intensities. The activity patterns of the males were not affected by those of the females. The thoracic temperatures of patrolling males were lower than those of perching males under cool conditions, suggesting that patrolling males lose heat more easily. In contrast, perching males may more easily regulate their body temperature to a suitable level as they fly for shorter periods and can bask while waiting for mates. These results highlight several reasons (i.e., heat loss, energetic costs) why males patrol when weather conditions are favourable.

Descriptions of larvae of Megadytes (Coleoptera: Dytiscidae: Dytiscinae): The subgenera Trifurcitus and Megadytes s. str., ground plan of chaetotaxy of the genus and phylogenetic analysis

Mariano C. MICHAT

Eur. J. Entomol. 107 (3): 377-392, 2010 | DOI: 10.14411/eje.2010.047

The three larval instars of Megadytes (M.) carcharias Griffini and M. (Trifurcitus) fallax (Aubé) are described and illustrated in detail for the first time, with an emphasis on morphometry and chaetotaxy of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. The ground plan of chaetotaxy of the genus Megadytes Sharp is described and illustrated based on three of the four recognised subgenera. First-instar larvae of Megadytes are characterised by the presence of a large number of additional sensilla on almost every part of the body. Primary chaetotaxy of the subgenera (Bifurcitus Brinck based on third instar) is very similar, with few differences including (1) shape of the setae on the anterior margin of the frontoclypeus; (2) presence or absence of a ring of multi-branched setae on distal third of mandible; and (3) number of setae on the urogomphus. A cladistic analysis of Dytiscidae, based on 169 larval characters and 34 taxa, indicates that: (1) Trifurcitus Brinck deserves generic status; (2) Cybistrini are not closely related to Hydroporinae; (3) the absence of a galea in Cybistrini is a secondary loss independent of that in Hydroporinae; (4) Cybistrini are well supported by many characters (including several aspects of first-instar chaetotaxy).

"DNA barcoding" is of limited value for identifying adelgids (Hemiptera: Adelgidae) but supports traditional morphological taxonomy

Martina ®UROVCOVÁ, Jan HAVELKA, Petr STARÝ, Pavlína VĚCHTOVÁ, Daniela CHUNDELOVÁ, Andrea JARO©OVÁ, Lucie KUČEROVÁ

Eur. J. Entomol. 107 (2): 147-156, 2010 | DOI: 10.14411/eje.2010.020

The sequence diversity in the mitochondrial cytochrome-c oxidase I (COI) gene was evaluated as a tool for resolving differences among species of European adelgids collected from several localities across the Czech Republic. Members of 7 genera and 16 species were examined, and as outgroups, two species of Phylloxeridae were used. Sequence divergences within species were on average less than 0.15%, whereas divergences between species ranged from 0.0 to 4.12% for congeneric and to 13.24% for intergeneric comparisons. It is concluded that DNA barcoding of Adelgidae is a powerful tool for identifying genera, but at the species level it works only in those cases where there are no species complexes. Nevertheless, it can be used as a complement to traditional, morphological taxonomy.

Alternative foods for the multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae)

Nick BERKVENS, Carmen LANDUYT, Koen DEFORCE, Dirk BERKVENS, Luc TIRRY, Patrick DE CLERCQ

Eur. J. Entomol. 107 (2): 189-195, 2010 | DOI: 10.14411/eje.2010.025

The multicoloured Asian lady beetle Harmonia axyridis (Coleoptera: Coccinellidae) may potentially exploit a range of "alternative" food sources. The nutritional value of three common non-prey food groups, i.e. fruit, fungi and pollen, is examined in this study. Development, reproduction and survival of the species were assessed in the laboratory on diets of apple, pear and raspberries and the fungi Oidium lycopersicum, Botrytis cinerea, Sclerotinia sclerotiorum and Rhizoctonia solani. When fed exclusively on these foods this ladybird failed to complete its development or reproduce. However, larval and adult survival was prolonged by 4 to 8 days and 55 to 67 days, respectively, when fruit was offered compared with only water. During a field study H. axyridis adults were collected monthly from March to October at two locations near Ghent, Belgium. Gut analysis demonstrated that, despite the continued presence of aphids, over 90% of all the adults collected contained pollen throughout the year. The pollen belonged to 53 different pollen types. Monthly average numbers of pollen grains in the gut varied from 5 to 233 grains. In contrast, there were about 35,000 grains in the guts of H. axyridis females that successfully developed and reproduced in the laboratory on diet that consisted of only pollen. This suggests that in the field in the majority of cases pollinivory mainly only provided complementary nutrients for this coccinellid. The use of alternative non-prey foods like pollen and fruit may play a role in sustaining populations of this coccinellid at times when the optimal prey is absent.

Does climate influence phenological trends in social wasps (Hymenoptera: Vespinae) in Poland?

Piotr TRYJANOWSKI, Tadeusz PAWLIKOWSKI, Krzysztof PAWLIKOWSKI, Weronika BANASZAK-CIBICKA, Tim H. SPARKS

Eur. J. Entomol. 107 (2): 203-208, 2010 | DOI: 10.14411/eje.2010.027

Responses of insects to recent climate change have been well documented in a number of taxa, but not in wasps. This study examined shifts in phenology of the two most important wasp species (Vespa crabro and Vespula germanica) in Poland over the last three decades. Both species showed similar temporal trends, advancing their phenology after the early 1980s, but this pattern was detected only for workers not for the appearance of queens. The appearance times for V. germanica were negatively related to mean April temperature, appearing earlier in years with warmer springs, and positively related to precipitation in April. The studied species advanced aspects of their phenology, but linking this to temperature was not achieved for V. crabro suggesting that we have to pay more attention to the life history traits of the study organisms.

Intraguild interactions between the predatory hoverfly Episyrphus balteatus (Diptera: Syrphidae) and the Asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae): Effect of larval tracks

Raki ALMOHAMAD, François J. VERHEGGEN, Frédéric FRANCIS, Eric HAUBRUGE

Eur. J. Entomol. 107 (1): 41-45, 2010 | DOI: 10.14411/eje.2010.004

The effects of the larval tracks of Episyrphus balteatus DeGeer (Diptera: Syrphidae) and Harmonia axyridis Pallas (Coleoptera: Coccinellidae) on the egg laying behavior of females of the predatory hoverfly E. balteatus were investigated in two-choice experiments. The oviposition response of H. axyridis to larval tracks of E. balteatus was also tested in one-choice experiments. Gravid E. balteatus females laid significantly fewer eggs on leaf discs with aphids and contaminated with tracks of conspecific or heterospecific larvae than on control leaf discs. H. axyridis females laid similar numbers of eggs in Petri dishes with aphids and contaminated with the tracks of E. balteatus larvae as in control Petri dishes. This indicates that E. balteatus females lay fewer eggs at sites where there are conspecific and heterospecific larval tracks, whereas the tracks of the syrphid larvae did not deter H. axyridis females from laying eggs.

Intrasexual fighting and mounting by females of the horned beetle Trypoxylus dichotomus (Coleoptera: Scarabaeidae)

Yutaka IGUCHI

Eur. J. Entomol. 107 (1): 61-64, 2010 | DOI: 10.14411/eje.2010.007

Although females of the horned beetle, Trypoxylus dichotomus septentrionalis, have only small horns they often fight over access to feeding sites by head-butting each other. In addition, they sometimes show intrasexual mounting. In this study 82 females of different sizes were used to determine the relationship between fighting and mounting. Large females more often won fights and so gained access to food than small females. In contrast, small females more often mounted large females and then gained access to food than large females. These results suggest that female mounting may function as a tactic for reducing intrasexual fighting between small and large females.

Incidence of infection of carabid beetles (Coleoptera: Carabidae) by laboulbenialean fungi in different habitats

Shinji SUGIURA, Kazuo YAMAZAKI, Hayato MASUYA

Eur. J. Entomol. 107 (1): 73-79, 2010 | DOI: 10.14411/eje.2010.009

The prevalence of obligate parasitic fungi may depend partly on the environmental conditions prevailing in the habitats of their hosts. Ectoparasitic fungi of the order Laboulbeniales (Ascomycetes) infect arthropods and form thalli on the host's body surface. Although several studies report the incidence of infection of certain host species by these fungi, quantitative data on laboulbenialean fungus-host arthropod interactions at the host assemblage level are rarely reported. To clarify the effects of host habitats on infection by ectoparasitic fungi, the incidence of infection by fungi of the genus Laboulbenia (Laboulbeniales) of overwintering carabid beetles (Coleoptera: Carabidae) in three habitats, a riverside (reeds and vines), a secondary forest and farmland (rice and vegetable fields), were compared in central Japan. Of the 531 adults of 53 carabid species (nine subfamilies) collected in the three habitats, a Laboulbenia infection of one, five and one species of the carabid subfamilies Pterostichinae, Harpalinae and Callistinae, respectively, was detected. Three species of fungus were identified: L. coneglanensis, L. pseudomasei and L. fasciculate. The incidence of infection by Laboulbenia was higher in the riverside habitat (8.97% of individuals; 14/156) than in the forest (0.93%; 2/214) and farmland (0%; 0/161) habitats. Furthermore, the incidence of infection by Laboulbenia in the riverside habitat ranged from 0 to 33.3% and differed significantly in the ten microhabitats (riverbank, edge of track, tall reeds, kudzu vines, slope of a hollow, rotten wood, vine reeds, under stones, the shoulder of a terrace and marshy ground) where the carabid beetles overwintered. These results suggest that host habitats and microhabitats are closely associated with successful infection by laboulbenialean fungi.

Habitat preferences influencing populations, distribution and conservation of the endangered saproxylic beetle Cucujus cinnaberinus (Coleoptera: Cucujidae) at the landscape level

Jakub HORÁK, Eva VÁVROVÁ, Karel CHOBOT

Eur. J. Entomol. 107 (1): 81-88, 2010 | DOI: 10.14411/eje.2010.011

Cucujus cinnaberinus (Scopoli, 1763) is a saproxylic beetle listed in the IUCN Red List and the European Habitats Directive. Although the species is highly protected and often red-listed little is known about its ecological requirements and status of its populations. Therefore, our main aims were to review its current and historical distributions and status of C. cinnaberinus populations in Europe and to determine its recent habitat preferences at the landscape level in the Czech Republic, where the increasing number of records over the last few years indicates a possible increase in abundance of this beetle. Cucujus cinnaberinus is closely associated with soft-wood and broad leaved trees and is able to colonize man-made habitats from persisting local populations if there is a sufficient supply of suitable dead wood. This beetle is not restricted to old-growth forests or even relict woodland, as previously reported, but currently predominantly inhabits abandoned planted stands of trees like lignicultures or avenues, which have an open canopy. Colonization of stands dominated by hybrid poplars probably resulted in the recent increase in the number of records of this species in the central European countries. However, this could present problems for the protection of this species in future, because the trees in these stands are gradually dying and are not being replaced. The decline and extinction of C. cinnaberinus on the northern and southern edges of its distribution was probably caused by the absence of soft-wooded broadleaved trees in intensively managed forests and other more suitable habitats.

Species coexistence patterns in a mycophagous insect community inhabiting the wood-decaying bracket fungus Cryptoporus volvatus (Polyporaceae: Basidiomycota)

Kohmei KADOWAKI

Eur. J. Entomol. 107 (1): 89-99, 2010 | DOI: 10.14411/eje.2010.012

A study of the insect community inhabiting the wood-decaying bracket fungus, Cryptoporus volvatus was used to test two hypotheses proposed to account for the competitive coexistence of species in insect communities in patchy environments, niche partitioning and spatial mechanisms. A total of 8990 individuals belonging to 17 insect species emerged from 438 sporocarps (patches) collected from the field. Insect species richness increased and then declined with increase in the total insect biomass reared from a sporocarp, suggesting the potential importance of interspecific competition. Successional niche partitioning explained the spatial distribution of the four specialist species. The aggregation model of coexistence satisfactorily explained the stable coexistence of the species. The specialist species displayed higher population persistence than the generalists. Simulation studies suggest that restricted movements of adults could override patch-level larval aggregation. The effect of such restricted movements on stabilizing coexistence in fungus-insect communities has not been previously appreciated. These findings suggest that spatial mechanisms play a crucial role in the competitive coexistence of the species in the mycophagous insect communities inhabiting bracket fungi.

The aquatic leaf beetle Macroplea mutica (Coleoptera: Chrysomelidae) in Europe: Population structure, postglacial colonization and the signature of passive dispersal

Michael MENDE, Olof BISTRÖM, Edda MEICHSSNER, Gregor KÖLSCH

Eur. J. Entomol. 107 (1): 101-113, 2010 | DOI: 10.14411/eje.2010.013

The pattern of postglacial re-colonization of Europe and the present population structure are known for various plant and animal species. The reed beetle Macroplea mutica (Fabricius, 1792) has characteristics that should influence both aspects in a peculiar way and therefore complement the currently known scenarios: It is fully aquatic but cannot swim or fly. Samples from 25 European populations of M. mutica and five specimens from China were investigated using amplified fragment length polymorphism (AFLP, 251 loci). Assessment of error rates associated with this method showed that the data set contains a strong population genetic signal. As hypothesized pronounced population differentiation and signs of inbreeding were found. Italian populations are clearly differentiated from northern populations (and from each other), which underlines the role of the Alps as a major barrier. Specimens from Lake Balaton (Hungary) show some affiliation with the populations in the Baltic Sea, which are all relatively similar. Populations from the eastern part of Northern Germany are similar to the Baltic populations, while those from the western part are allied to the British populations. The hypothesis is that the recolonization of Europe was from both the Southeast and a western refugium in the area of present-day southern England or Ireland, which resulted in a suture zone in Northern Germany. The effect of passive dispersal by drift attached to host plant material (especially in the Baltic Sea) and by zoochory (migrating waterfowl) is discussed.

Genetic and morphological differentiation between isolated Polish populations of "glacial relict", an endangered butterfly, Oeneis jutta (Lepidoptera: Nymphalidae)

Lech KRZYSZTOFIAK, Anna KRZYSZTOFIAK, Krzysztof FRˇCKIEL, Anna BIAŁA, Adrianna KILIKOWSKA, Jerzy SELL

Eur. J. Entomol. 107 (1): 115-120, 2010 | DOI: 10.14411/eje.2010.014

This is the first study of the morphological and molecular variation in two peripheral populations of the butterfly Jutta Arctic, Oeneis jutta, a glacial relict species endangered by the fragmentation of its habitat in Poland. An analysis of the morphological characteristics indicates that both Polish populations are similar but differ significantly in some characteristics. Levels of genetic variation were assessed using mitochondrial cytochrome oxidase subunit I (COI) and NADH dehydrogenase subunit 5 (ND5) gene fragments together with a segment of the mtDNA control region (CR) and a nuclear elongation factor-1a (EF-1a) gene sequence. In addition, the pattern of molecular variation in specimens from eastern and northern Europe was examined. Interestingly, the analysis of variation in a 932-bp sequence of the nuclear EF-1a gene in representatives of the populations studied revealed a relatively higher level of diversity than that of mitochondrial genes. There was evidence of divergence between the peripheral populations and lack of gene flow between them. The two closely situated populations had a high FST value (0.69), which clearly indicates their isolation. These populations appear to be demographically independent breeding units, with distinctive allele frequencies and consequently should be recognized as separate units for management and conservation. The preliminary results are in accord with an a priori subdivision based on collection areas and suggest that habitat fragmentation has affected the genetic diversity and structure of these populations.

Isolation and characterization of oligomerization domain I and II coding regions of doublesex genes in agricultural fruit flies (Diptera: Tephritidae)

Rattiya PERMPOON, Sujinda THANAPHUM

Eur. J. Entomol. 107 (1): 121-126, 2010 | DOI: 10.14411/eje.2010.015

Bactrocera fruit flies are ranked among the most destructive pests of the worldwide fruit and vegetable trades. Coding regions of two oligomerization domains within doublesex (dsx) genes were determined in Bactrocera dorsalis (oriental fruit fly) and B. correcta (guava fruit fly). Resulting sequences revealed a high degree of similarity at both nucleotide and putative amino acid levels in the genus Bactrocera. Conservation of the DNA-binding DM motif and several known molecular features within the domains suggest a presence of strong purifying selection on the DSX proteins. Topology of the phylogenetic gene trees and deduced amino acid substitution patterns suggest that the coding region sequences of the two domains are diversified in concert parallel with the species differentiation.

The importance of habitat mosaics for Orthoptera (Caelifera and Ensifera) in dry heathlands

Jens SCHIRMEL, Irmgard BLINDOW, Thomas FARTMANN

Eur. J. Entomol. 107 (1): 129-132, 2010 | DOI: 10.14411/eje.2010.017

In summer 2008, the Orthopteran species Chorthippus biguttulus, Myrmeleotettix maculatus (Caelifera), Decticus verrucivorus and Platycleis albopunctata (Ensifera) were sampled in coastal heathland on the German Baltic Sea island of Hiddensee. The aim of this study was to assess differences in abundance of Orthoptera in three different habitats and determine the importance of habitat mosaics. Distribution patterns varied among species and total abundance of Orthoptera differed significantly among the three habitats. Due to species-specific habitat preferences the Caelifera were most abundant in grey dunes and the Ensifera in dwarf-shrub heath adjoining grey dunes. In conclusion, grey dunes are a suitable habitat for the Caelifera studied, while the Ensifera require a heathland mosaic consisting of both grey dunes and dwarf shrub vegetation.

Light intensity affects spatial distribution of Heteroptera in deciduous forests

Martin M. GOSSNER

Eur. J. Entomol. 106 (2): 241-252, 2009 | DOI: 10.14411/eje.2009.032

Studies on the effect of varying light intensity on the spatial distribution of flying insect communities are rare, particularly in complex ecosystems like forests. The horizontal and vertical distribution of Heteroptera was studied at different scales in a large deciduous forest area, the "Steigerwald", in southern Germany. Diversity was affected by (1) vertical position: it was significantly higher near the ground than in the canopy of beech-dominated forests but similar in oak-dominated forests; within the canopy of beech-dominated forests, diversity was significantly higher in the upper than in the lower canopy of intermixed oak trees but similar in beech trees; (2) canopy cover, but in oak forests the response depended on the vertical position: increasing significantly close to the forest floor with decreasing canopy cover, but showing an opposite trend in the canopy; so that in sparse stands (little canopy cover) diversity was significantly higher near the ground, whereas where the forest canopy was medium or dense diversity was higher in the canopy. Moreover, community composition of Heteroptera near the ground differed from that in the canopy in both forest types and near the ground between stands in oak-dominated forest that had canopies of different densities. Results clearly indicate that light intensity is an important direct or indirect factor structuring Heteroptera communities. While in the canopy differences in leaf quality and microhabitats might be important, near the forest floor it is more likely to be the diversity of herbaceous plants.

Male flies with yellow balls - New observations on the eversible vesicles on the postabdomen of male Thaumatomyia notata (Diptera: Chloropidae)

Marion KOTRBA

Eur. J. Entomol. 106 (1): 57-62, 2009 | DOI: 10.14411/eje.2009.009

The paired eversible vesicles on the postabdomen of male T. notata are likely to play an important role in intraspecific communication and possibly in the notorious aggregation behaviour of these flies at buildings in autumn. The morphological and histological study of these organs provides new evidence supporting the hypothesis that they are pheromone glands. They also constitute a strong optical signal. A detailed survey of these structures could provide the bases for targeted control methods.

Seasonal occurrence and local coexistence within scarabaeid dung beetle guilds (Coleoptera: Scarabaeoidea) in Tunisian pasture

Faïek ERROUISSI, Imen LABIDI, Saïd NOUIRA

Eur. J. Entomol. 106 (1): 85-94, 2009 | DOI: 10.14411/eje.2009.013

Dung beetle assemblages were monitored using baited pitfall traps from January to December 2006 in Northern Tunisia. 4,965 beetles belonging to 37 species were trapped. Aphodius lineolatus and Onthophagus taurus dominated the assemblages. Results showed a significant seasonal variation in assemblage composition, and diversity. There were four periods of activity during the course of the year. Temporal turnover was highest in October and in February. Temporal distribution of species shows seasonal segregation and opposite patterns in the two dominant guilds (Aphodiinae-dwellers and Scarabaeidae-tunnelers). Aphodiidae-dwellers were active from autumn to spring, although they were affected by summer drought. The Aphodius-dweller showed high temporal plasticity and phenological segregation. In contrast, Scarabaeidae-tunnelers were active all year round but mainly in the spring-summer period and less so in winter. Species in this guild showed a high degree of phenological overlap and a short ecological length. Our results suggest that coexistence in dung beetle guilds is facilitated by their phenological patterns, which reflect distinct ecological requirements and biogeographical origin of species. Geotrupidae-tunnelers and Scarabaeidae-rollers were rare and occurred mainly in the summer-autumn period, when individuals of the two other guilds were rare.

Why is Coccinella septempunctata so successful? (A point-of-view)

Ivo HODEK, J.P. MICHAUD

Eur. J. Entomol. 105 (1): 1-12, 2008 | DOI: 10.14411/eje.2008.001

Factors were examined that could be responsible for the predominance of Coccinella septempunctata (C7) in most habitats of the Palaearctic and for its successful invasion of the Nearctic Region. C7 is euryphagous, but less polyphagous than Harmonia axyridis or Coleomegilla maculata in that it cannot develop or reproduce on non-aphid food. The intraguild status of C7 is intermediate. Although adult size is large, preimaginal stages are palatable to those of H. axyridis and Adalia bipunctata, whereas it is not an intraguild predator of these species. Although these traits appear to be neutral or negative, many aspects of population plasticity are advantageous for C7, often acting in concert with a bet-hedging strategy. Given its high mobility and eurytopy, the inhibition of oviposition in the presence of conspecific larval trails represents an adaptive advantage that favors increased egg dispersal and lowers the risk of offspring mortality due to cannibalism. The ability to temporarily suspend oviposition, combined with heterogenous voltinism and diapause tendencies, enable a portion of C7 populations to feed and reproduce on unpredictably occurring aphid populations. An absence of reproductive diapause in males and pre-hibernation mating are other significant adaptations, along with the tendency to produce offspring in excess of the carrying capacity of local food resources. We suggest that one explanation for the broad geographic success of C7 resides in an ecological plasticity that is based on both genetic and phenotypic polymorphisms.

Expression of the melittin gene of Apis cerana cerana (Hymenoptera: Apidae) in insect cells

Wan-Jun SHI, Jia-An CHENG, Chuan-Xi ZHANG

Eur. J. Entomol. 103 (4): 867-870, 2006 | DOI: 10.14411/eje.2006.118

A fragment encoding melittin cDNA from Apis cerana cerana fused with glutathione S-transferase gene was inserted into the multiple cloning site of the pBacFastHTb to construct a recombinant donor plasmid, pBacHT-GSTAccM, which was transposed to the target bacmid in E. coli (DH10) by Tn7 transposition function. Then the recombinant baculovirus Bacmid-GSTAccM was transfected into Tn-5B1-4 cells of the cabbage looper, Trichoplusia ni, mediated by lipofectin. The expressed protein of about 34 kDa was detected by Western blotting and triple antibody sandwich ELISA, indicating that the recombinant protein is the fusion protein of GSTAccM. Thin layer scanning showed that the expression level of GSTAccM was about 7% of the total cell protein. Purified and recovered recombinant melittin of A. c. cerana showed bioactivity in activating rabbit platelets to aggregate.

Egg-laying preferences of the xerophilous ecotype of Maculinea alcon (Lepidoptera: Lycaenidae) in the Aggtelek National Park

Ervin ÁRNYAS, Judit BERECZKI, Andrea TÓTH, Katalin PECSENYE, Zoltán VARGA

Eur. J. Entomol. 103 (3): 587-595, 2006 | DOI: 10.14411/eje.2006.079

The oviposition sites of the xerophilous ecotype of M. alcon (= "Maculinea rebeli") were surveyed in the managed (transitional) zone of the Aggtelek National Park and Biosphere Reserve in Northern Hungary. The M. alcon population is distributed over a territory of about 3 ha. In 2001, habitat reconstruction with selective cutting of shrubs and mowing, was started in this area. The number of stems of Gentiana cruciata (the food plant for the young larvae) and M. alcon eggs layed on them were counted in a selected area within this 3 ha: before (in 1992, 1993 and 1998) and after habitat reconstruction (in 2003, 2004 and 2005). In 2004 and 2005, a detailed study was carried out in order to detect potentially significant factors influencing the egg laying behaviour of females. The average number of intact flowering stems per quadrate was 2.68 and was clearly decreasing before management started. In contrast, there were five times higher (15.06) and increasing numbers of stems per quadrate right after habitat reconstruction. The two periods also differed in the percentage of flowering stems, which was very low before habitat reconstruction. The average number of eggs per square was low (6.8) and fluctuated considerably before management started. In contrast, the egg count was high (160.3) and increased consistently after the site was managed. The short grass sward created in the area proved to be advantageous both for the growth of the host plant and for the Maculinea population. The egg laying preference of the females was positively affected by the number of stems per clump, the height of the stems, the number of whorls with flowers and the difference between the height of the stems of the host plant and the surrounding vegetation. Significantly more eggs were found on large clumps of stems than expected on the basis of their availability for egg-laying. Egg counts were strongly correlated with all the measured characteristics of the food plant, which significantly correlated with each other. The interaction term indicated that the number of whorls with flowers is slightly more influential for egg laying than the other characteristics. There were significantly more eggs on the adaxial surface of the leaves and flower buds than on other parts of the food plant.

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