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Results 901 to 930 of 2340:

Seasonal occurrence and biological parameters of the common green lacewing predators of the common pistachio psylla, Agonoscena pistaciae (Hemiptera: Psylloidea)

Fatemeh KAZEMI, Mohammad Reza MEHRNEJAD

Eur. J. Entomol. 108 (1): 63-70, 2011 | DOI: 10.14411/eje.2011.008

Species in the carnea complex of the common green lacewing are predators of the common pistachio psylla, Agonoscena pistaciae in both cultivated pistachio plantations and on wild pistachio plants in Iran. The seasonal occurrence of common green lacewings was monitored in pistachio orchards from 2007 to 2008. In addition, the effect of different temperature regimes on preimaginal development, survival and prey consumption of the predatory lacewing Chrysoperla lucasina fed on A. pistaciae nymphs were studied under controlled conditions. The adults of common green lacewings first appeared on pistachio trees in mid April and were most abundant in early July, decreased in abundance in summer and increased again in October. The relative density of common green lacewings was higher in pistachio orchards where the ground was covered with herbaceous weeds than in those without weeds. In the laboratory females of C. lucasina laid an average of 1085 eggs over 60 days at 22.5°C. The maximum prey consumption occurred at 35°C when the larvae consumed 1812 fourth instar psyllid nymphs during their larval period. The intrinsic rate of natural increase (rm) was 0.11. The total development (egg-adult) required 385 degree-days above the theoretical lower developmental threshold of 9.6°C.

Survival of ground beetles (Coleoptera: Carabidae) submerged during floods: Field and laboratory studies

Felix N. KOLESNIKOV, Arevik N. KARAMYAN, W. Wyatt HOBACK

Eur. J. Entomol. 109 (1): 71-76, 2012 | DOI: 10.14411/eje.2012.009

Field and laboratory experiments were conducted to assess the time ground beetles (Coleoptera: Carabidae) survive during actual and simulated flood conditions. The effects of three variants of potential flood conditions were tested: (1) beetles trapped on the surface of flood water; (2) beetles trapped in air pockets; (3) submersion of beetles in flood water without access to air. Ground beetles trapped on the surface of water survived more than two weeks (Carabus granulatus - up to 16 days; Oxypselaphus obscurus - up to 22 days). Carabus granulatus in simulated hibernation chambers that had air-pockets also survived for 15 days. The time for which ground beetles submerged without access to air survived differed significantly among species and was affected by season. They survived longest in mid-spring and late-autumn when water temperature is low. In mid-spring, survival times for C. granulatus and Platynus assimilis were 12 days and 9 days, respectively. During late summer and early autumn all species survived for a shorter period of time. In August, at least half of the individuals tested were dead after three days of immersion (water temperature 16-18°C). Removal of both of the elytra of adult of C. granulatus resulted in them surviving immersion for a shorter period, which indicates that air stored in the sub-elytral cavity is used to prolong the period they can survive immersion. The results of these experiments broaden the knowledge of how adult beetles survive seasonal flooding and are able to persist in floodplain habitats.

Insertion of miniature subterminal inverted repeat-like elements in diapause-regulated genes in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

George D. YOCUM, Michelle J. TOUTGES, Richard L. ROEHRDANZ, Preston J. DIHLE

Eur. J. Entomol. 108 (2): 197-203, 2011 | DOI: 10.14411/eje.2011.027

Determining the genomic structure of diapause-associated transcripts (DAT) -2 and -3 led to the isolation of four novel miniature subterminal inverted repeat-like elements (MSITE): Mild-1, -2, -3 and -4. Mild-1a is inserted within the first intron of diapause protein-1. Mild-1a is 284 bp in length, has a 14 bp target site duplication and three sets of subterminal inverted repeats. The second element, Mild-2a, is inserted within the 3' terminus of Mild-1a. Mild-2a is 29 bp long with a 3 bp target site duplication and one set of subterminal inverted repeats. Using primers based on Mild-1, genomic clones were developed leading to the isolation of Mild-3a. Mild-3a shares 60% identity with Mild-1a, is 253 bp long, has a 9 bp target site duplication and has one set of subterminal inverted repeats. Mild-4a is inserted within the first intron of DAT-2 and is 227 bp in length with a 12 bp target site duplication. Mild-4a appears to be an intermediate form between a miniature inverted repeat transposable element (MITE) and a MSITE because the 5' inverted repeat is terminal (i.e., adjacent to the target site duplication) as in MITEs, but the 3' inverted repeat is separated (in this case, by 33 bp) from the 3' target site duplication as in MSITEs. The target site duplications of Mild-1, -3 and -4 families share a common conserved core of AATTT. All of the transposable elements are AT rich and are able to form hairpin structures. Within the promoter region of DAT-3 is a 163 bp sequence (Mild-1b) that shares 77% identity to the 3' terminus of Mild-1a. Mild-4a has identity to 25 and 53 bp regions within the promoter of the juvenile hormone esterase B gene. Southern blot analysis revealed the presence of Mild-1 and -3 elements in both Leptinotarsa decemlineata and Leptinotarsa juncta indicating that these elements are ancestral to the L. decemlineata, L. juncta separation.

Recombinant expression, purification and characterization of Bombyx mori (Lepidoptera: Bombycidae) pyridoxal kinase

Shuo-Hao HUANG, Wang MA, Ping-Ping ZHANG, Jian-Yun ZHANG, Yan-Feng XIE, Long-Quan HUANG

Eur. J. Entomol. 108 (1): 25-34, 2011 | DOI: 10.14411/eje.2011.003

Pyridoxal kinase (PLK; EC 2.7.1.35) is a key enzyme in the metabolism of vitamin B6 (VB6) in Bombyx mori. A fusion expressional vector pET-22b-BPLK-His was constructed using a sub-cloning technique, the recombinant B. mori PLK was then expressed in Escherichia coli, purified and characterized. Bioinformatics were used to deduce the protein structure and genomic organization of this enzyme. Using Ni Sepharose affinity column chromatography, the recombinant protein was purified to very high degree (approximately 90%). The recombinant PLK exhibits a high specific enzymatic activity (1800 nmol/min/mg of protein). The maximum catalytic activity of this enzyme was recorded over a narrow pH range (5.5-6.0) and Zn2+ is the most effective cation for catalysis under saturating substrate concentrations. When only triethanolamine is present as the cation, K+ is an activator of PLK. A double reciprocal plot of initial velocity suggests that the enzyme catalyses the reaction by means of a sequential catalytic mechanism. Under optimal conditions, the Km value for the substrates of ATP and pyridoxal are 57.9 ± 5.1 and 44.1 ± 3.9 µM. B. mori's genome contains a single copy of the PLK gene, which is 7.73 kb long and contains five exons and four introns, and is located on the eighth chromosome. The PLK may be a dimer with two identical subunits under native conditions, and it is hypothesized that each monomer contains eight α-helices (α1-8), nine β-strands (β1-9) and two segments of 310 helices.

BOOK REVIEW: Naskrecki P.: The Smaller Majority.

T. SOLDÁN

Eur. J. Entomol. 104 (2): 234, 2007 | DOI: 10.14411/eje.2007.036

The Belknap Press of Harvard University Press, Cambridge, MA, and London, UK, 2005, 278 pp., ISBN 0-674-01915-6 (hard cover). Price USD 35.00, GBP 21.95.

The identity of Pseudopsila, description of a new subgenus of Psila, and redefinition of Psila sensu lato (Diptera: Psilidae)

Matthias BUCK, Stephen A. MARSHALL

Eur. J. Entomol. 103 (1): 183-192, 2006 | DOI: 10.14411/eje.2006.021

The type species of Pseudopsila Johnson, P. fallax (Loew), and two related species are found to belong in Psila s. str., and Pseudopsila is thus synonymized with Psila Meigen. The remaining species formerly included in Pseudopsila form a monophyletic group here described as Xenopsila Buck subgen. n. [i.e., Psila (Xenopsila) collaris Loew comb. n., P. (X.) bivittata Loew comb. n., P. (X.) lateralis Loew comb. n., P. (X.) arbustorum Shatalkin comb. n., P. (X.) nemoralis Shatalkin comb. n., P. (X.) tetrachaeta (Shatalkin) comb. n., P. (X.) maculipennis (Frey) comb. n., P. (X.) nigricollis (Frey) comb. n., P. (X.) nigrohumera (Wang & Yang) comb. n.]. A key to the Nearctic species of Xenopsila and the Psila fallax-group is provided. The placement of Xenopsila in Psila s. l. is confirmed by newly recognised synapomorphies of the egg stage. The somewhat questionable monophyly of Psila s. l. is confirmed based on these new synapomorphies, thereby slightly expanding its taxonomic limits to also include Asiopsila Shatalkin. The morphology of the male genitalia of Xenopsila is discussed in detail, clarifying confused homologies and character polarities in the hypandrial complex. Evolutionary trends in the development of the hypandrium in the subfamily Psilinae are discussed.

Altitudinal trends in the phenology of butterflies in a mountainous area in central Spain

Juan Ignacio De ARCE CRESPO, David GUTIÉRREZ

Eur. J. Entomol. 108 (4): 651-658, 2011 | DOI: 10.14411/eje.2011.083

One of the best documented effects of climate change on biodiversity are shifts in phenology. However, long-term data quantifying and projecting the expected changes in phenology associated with climate warming are limited to a few well-recorded areas in the world. In the absence of temporal recording, an alternative approach is to determine the phenological response of species along marked gradients in climate or along latitudinal or altitudinal transects (space-for-time substitution). We studied the phenology (timing and duration of the flight period) of butterflies in 2006 along an altitudinal gradient (900-1680 m; estimated temperature lapse rate = -6.6°C/km) in the Serranía de Cuenca (central Spain) at the assemblage and individual species levels. Timing of the flight period was later for assemblages at high than at low altitudes. A similar trend of an increasing delay in the flight period with altitude was recorded for some individual species. However, there were also some exceptions to this pattern regardless of the number of sites and the altitudinal ranges of the species, suggesting possible local adaptation to regional climate. The duration of the flight period was shorter at high altitudes for assemblages, but this trend was not mirrored in the response of individual species. The results partly support substituting space-for-time when assessing the potential effect of climate change on phenophases such as the timing of the flight period, but we recommend extreme caution in extrapolating the results in the absence of information on how the responses of populations differ.

Ground-dwelling arthropod assemblages of partially improved heathlands according to the species of grazer and grazing regime

Rocío ROSA GARCÍA, Urcesino GARCÍA, Koldo OSORO, Rafael CELAYA

Eur. J. Entomol. 108 (1): 107-115, 2011 | DOI: 10.14411/eje.2011.014

The creation of improved areas is one way of increasing the productivity of livestock on Cantabrian heathland (NW Spain), a habitat that is frequently located in less favourable mountainous areas where the development of sustainable husbandry is limited. The effect of this on the biodiversity of heathland is unclear and likely to depend on several factors, such as the grazing regime. In order to clarify this situation, the effects of type of vegetation, species of grazer and grazing regime on the composition of the ground-dwelling arthropod fauna of partially improved heathland were determined. The effects of grazing by cattle or sheep and two grazing regimes (cattle or sheep, or both of them together with goats) were studied in eight plots (two replicates per treatment). Each plot included two types of vegetation, gorse (Ulex gallii)-dominated shrubland and improved grassland (Lolium perenne-Trifolium repens). Arthropods were surveyed using pitfall traps. Overall, the composition of the arthropod fauna did not differ between plots grazed by different species of grazer or using different grazing regimes but was significantly associated with the type of vegetation. Most of the opilionids and several carabids clearly preferred shrubland, while lycosids and various carabids were mainly associated with grassland. While the species of grazer affected the faunal composition of grassland, grazing regime was more important in shrubland. Arthropod responses to the grazing treatments were determined by the grazing behaviour of the large herbivores and the habitat requirements of each arthropod taxon. The great structural heterogeneity of the vegetation and the more microhabitats in shrubland grazed by mixed flocks was mainly a result of the goats preferring to browse on the woody vegetation in these areas. The grazing by either sheep or cattle had less of an affect on the fauna of shrubland than grassland.

Faunal patterns in Tuscan archipelago butterflies (Lepidoptera): The dominant influence is recent geography not paleogeography

Leonardo DAPPORTO, Alessandro CINI

Eur. J. Entomol. 104 (3): 497-503, 2007 | DOI: 10.14411/eje.2007.070

The aim of this paper is to examine whether current and/or Pleistocene geography affect the species richness and composition of Tuscan archipelago butterflies. This archipelago is located between Tuscany (Italy) and Corsica (France). Faunistic data was obtained from the literature and surveys. Our data revealed that contemporary geography is the most important factor determining the species richness and faunal composition of Tuscan archipelago butterflies. Indeed, current area and isolation of the islands are the only predictors significantly correlated with species richness. Paleogeographic features of the archipelago are not significantly correlated with species richness. Multidimensional scaling revealed patterns similar to those reported for other living groups. Specifically, Capraia and Montecristo group together with Corsica, while Elba, Giglio, Pianosa, Gorgona, Giannutri and the fossil island of Monte Argentario group with the Tuscan mainland. Recent geography seems to affect the faunal composition. Indeed Mantel test indicates that the similarity in the faunal composition of the Tuscan Archipelago islands is mainly related to present-day island characteristics and their relative distance from Tuscany and Corsica. Our results are similar to those recently obtained for Aegean archipelago butterflies.

Genetic variation in Turkish honeybees Apis mellifera anatoliaca, A. m. caucasica, A. m. meda (Hymenoptera: Apidae) inferred from RFLP analysis of three mtDNA regions (16S rDNA-COI-ND5)

Fulya ÖZDIL, Ibrahim AYTEKIN, Fatma ILHAN, Saim BOZTEPE

Eur. J. Entomol. 109 (2): 161-167, 2012 | DOI: 10.14411/eje.2012.021

In this study, the genetic structure of Turkish honey bee (Apis mellifera L.) populations, mainly obtained from the Central Anatolian region, were investigated at three different mitochondrial regions. A total of 165 worker bees were collected from 15 different populations in ten different locations. Portions of the mitochondrial 16S ribosomal RNA (16S rDNA), cytochrome C oxidase I (COI) and NADH dehydrogenase 5 (ND5) genes were amplified by PCR and then subjected to RFLP pattern analysis using 18 restriction enzymes (these having at least one recognition site in each region were used). Nucleotide polymorphisms were revealed using restriction enzymes Bsp143I, DraI and SspI in 16S rDNA and TaqI in the COI gene segment. The polymorphisms were subsequently confirmed by direct DNA sequencing with sequences thereafter deposited in Genbank. In this study, six novel composite genotypes (haplotypes) were found in Turkish honey bee populations. The most common haplotype, type 1, was found in 12 of the sampled populations and overall accounted for 85.5% of the samples. TCS spanning network of haplotypes revealed that type 1 was the basal haplotype. Genetic distance (D) values were found to be low (0.0-0.0112) within Turkish honey bee populations. The average haplotype diversity (h) within populations was 0.082. Molecular phylogenetic analysis revealed that Konya/Sizma, Antalya/Elmali and Konya/Selçuklu populations were the most distant from all the other Turkish honey bee populations surveyed.

Reproductive biology of the palm borer, Paysandisia archon (Lepidoptera: Castniidae)

Roxane DELLE-VEDOVE, Laurence BEAUDOIN-OLLIVIER, Martine HOSSAERT-MCKEY, Brigitte FRÉROT

Eur. J. Entomol. 109 (2): 289-292, 2012 | DOI: 10.14411/eje.2012.037

Paysandisia archon (Burmeister, 1980) (Lepidoptera: Castniidae) is an accidentally introduced pest that damages palm trees in the northern Mediterranean area. To our knowledge, there are no experimental studies on its mating behaviour, and little is known about its biology and ecology. In the present study, we used outdoor experiments to investigate several characteristics of the reproductive behaviour of P. archon: sexual maturity, diel periodicity of mating, occurrence of polyandry and delay between mating and laying eggs. The results indicate that 73% of the individuals studied were sexually mature three hours after adult emergence. Mating peaked between 14:00 h and 15:00 h and 87% of the females were fertilized and started laying eggs 1.25 (± 1.14) days after mating. Females were generally monandrous, but nevertheless remained attractive after mating. The results of this study provide the necessary background knowledge for studying several aspects of P. archon reproductive biology, in particular oviposition, sex pheromones and their role in mediating mating behaviour in this pest. These results are the first step in developing tools for monitoring populations of this pest.

Detection of a single nucleotide polymorphism (SNP) DNA marker linked to cocoon traits in the mulberry silkworm, Bombyx mori (Lepidoptera: Bombycidae)

Sivaramakurup SREEKUMAR, Southekal K. ASHWATH, Monika SLATHIA, Sundaramurthy N. KUMAR, Syed M.H. QADRI

Eur. J. Entomol. 108 (3): 347-354, 2011

Cocoon weight and shell weight are the key economic traits ultimately determining silk yield. In order to detect the main quantitative trait loci (QTL) associated with the cocoon traits of the mulberry silkworm, Bombyx mori, the parents of larvae that produced cocoons that differed greatly in weight and shell weight were screened using 240 primer pairs of single nucleotide polymorphic markers (SNPs) representing all the 28 linkage groups in silkworm. Out of the 240 primer pairs, 48 (20%) revealed distinct polymorphism between the parents, which was confirmed by the co-dominant expression of both polymorphic PCR products in the F1 generation. The bulked segregant analysis (BSA) was used to compare the SNP profiles of the parents, F1 and F2 bulks using the 48 informative SNP primers. This revealed that out of 48 primer pairs, only one pair, i.e., No. 04124 of the linkage group 4 showed clear differences in the amplified products between the bulks corresponding to that of the parents with different cocoon traits suggesting that the DNA regions amplified by this primer pair are closely linked to the QTL controlling the cocoon traits. The results were also confirmed by screening the backcross (BC) progeny. This is the first report of the identification of a QTL using SNPs with BSA. The results of the present study indicate that it might be possible to use SNPs for marker assisted selection (MAS) in silkworm breeding programs aimed at improving cocoon traits.

Seasonal constraints on the mandible allometry of Lucanus cervus (Coleoptera: Lucanidae)

Sönke HARDERSEN, Anna L.M. MACAGNO, Roberto SACCHI, Ilaria TONI

Eur. J. Entomol. 108 (3): 461-468, 2011

In insects, allometries of exaggerated traits such as horns or mandibles are often considered species specific and constant during a season. However, given that constraints imposed by the advancing season affect the developmental processes of organisms, these allometries may not be fixed, and the switch point between morphs may vary between populations and within populations during a season. The hypothesis of such a seasonal variation in exaggerated traits was tested using the dimorphic males of the beetle Lucanus cervus. The remains of specimens killed by predators were collected along forest tracks from mid May to late August 2008 in a protected lowland forest in northern Italy. The largest beetles were collected in mid May and average size thereafter decreased. Males collected early in the season mostly had large mandibles (i.e. they belonged to the major morph). In contrast, late in the season the probability of finding males with large mandibles was very low. The threshold body size determining morph expression also shifted during the season. Early in the season, the threshold pronotum width for a 50% chance of developing into the major morph was 1.74 cm, whereas later in the season it was 1.90 cm. This shift in the threshold body size was interpreted as the effect of phenotypic plasticity in a population exposed to constraints imposed by the advancing season.

Demography of adults of the Marsh fritillary butterfly, Euphydryas aurinia (Lepidoptera: Nymphalidae) in the Czech Republic: Patterns across sites and seasons

Kamil ZIMMERMANN, Pavla BLAZKOVA, Oldrich CIZEK, Zdenek FRIC, Vladimir HULA, Pavel KEPKA, David NOVOTNY, Irena SLAMOVA, Martin KONVICKA

Eur. J. Entomol. 108 (2): 243-254, 2011 | DOI: 10.14411/eje.2011.033

The Marsh fritillary (Euphydryas aurinia) (Lepidoptera: Nymphalidae) has declined across Europe, including the Czech Republic. Current conservation strategies rely on prevention of habitat loss and degradation, and increase in habitat quality and connectivity via promoting traditional grassland management. The population structure and adult demography parameters of a single population was investigated for eight years (single system), and of all the known Czech populations (multiple populations) for a single year, using mark-recapture. There was substantial variation in the patterns of adult demography, both among years in the single system and among the multiple populations in a single year. In the single system, the date of the first flight of an adult varied by 18 days over the 8 years and total annual numbers varied with a coefficient of variation of 0.40 (females fluctuating more than males). The average density was ca 80 adults/ha. The population size displayed density-dependence, i.e. decreased following years with high adult numbers, with an equilibrium density of 90 individuals/ha. The average density of the multiple populations was ca 120 individuals/ha. The estimated total population for the Czech Republic was 25,000 individuals (17,000 males / 8,000 females) in 2007, which does not indicate an imminent threat of extinction. The regional persistence of E. aurinia is likely to depend on re-colonisation of temporarily vacant sites by dispersing individuals, facilitated by local shifts in adult flight phenology to that better adapted to local conditions.

A new look at discontinuous respiration in pupae of Hyalophora cecropia (Lepidoptera: Saturniidae): Haemocoelic pressure, extracardiac pulsations and O2 consumption

Karel SLÁMA

Eur. J. Entomol. 107 (4): 487-507, 2010 | DOI: 10.14411/eje.2010.057

Discontinuous respiration in diapausing pupae of Cecropia silkworms was monitored by means of several electronic methods, including recording changes in haemocoelic pressure, monitoring respiratory movements by strain-gauge sensors and nanorespirographic recording of O2 consumption and CO2 output. It appears that, in contrast to previous concepts of stereotypic discontinuous respiration cycles (DGC) driven by accumulation of gaseous CO2 in the body, the new results indicate that CO2 remains dissolved in liquid carbonate buffers during interburst periods. In other words, there is no accumulation of gaseous CO2 within the air filled tracheal space between the bursts. The bursts of CO2 are caused by homeostatically regulated enzymatic hydration by carbonic anhydrase of metabolically produced carbonic acid. The chemically produced gaseous CO2 was exhaled mainly by a bulk outflow through selectively opened or pulsating spiracles. The output of CO2 was enhanced by actively regulated, unidirectional ventilation. The deep depressions in haemocoelic pressure, caused by permanent closure of all spiracular valves for long periods, appeared to be a specific feature of diapausing saturniid pupae. Physiologically, it has circulatory, not respiratory functions. The original definition of spiracular "fluttering" resulted from a misinterpretation of previously unknown extracardiac pulsations in haemocoelic pressure. The coordinated pulsation of the spiracular valves with extracardiac pulsations produce a very efficient, unidirectional ventilation of the whole tracheal system. According to the new results, the discontinuous respiration cycles of diapausing Cecropia pupae can be briefly described as follows: (1) Spiracular valves are kept permanently closed during the periods of deep depressions, they remain closed for some 99% of the time with occasional snap opening (passive inspirations) during prolonged interburst periods and more than 50% closed during the bursts; (2) During the long interburst periods, CO2 is retained in liquid carbonate buffers, while the relatively high (after the burst) or low (toward the next burst) rate of O2 consumption creates an internal vacuum, which is homeostatically compensated for by the snap-opening of one or just a few spiracular valves (passive suction inspirations); (3) The CO2 gas, produced enzymatically by carbonic anhydrase, enters the air filled tracheal system and leaves the body by diffusion, a bulk outflow, or actively regulated unidirectional ventilation ("fluttering" spiracles). The selective advantage of this actively regulated respiratory system for water retention in pupae is discussed.

Revision of the Poecilimon ornatus group (Orthoptera: Phaneropteridae) with particular reference to the taxa in Bulgaria and Macedonia

Dragan P. CHOBANOV, Klaus-Gerhard HELLER

Eur. J. Entomol. 107 (4): 647-672, 2010 | DOI: 10.14411/eje.2010.073

The Poecilimon ornatus group has an exclusively European distribution and includes the largest species in the genus. A revision of the taxa belonging to this group in Bulgaria and Macedonia (Central and Eastern Balkan Peninsula) is presented. Nine taxa described from Bulgaria are synonymised with 3 previously known species, as follows: Poecilimon ornatus (= P. mistshenkoi marzani, syn. n., P. mistshenkoi tinkae, syn. n., P. mistshenkoi vlachinensis, syn. n.), P. affinis s. str. (= P. mistshenkoi mistshenkoi, syn. n., P. affinis ruenensis, syn. n., P. affinis rilensis, syn. n., P. affinis medimontanus, syn. n., P. harzi, syn. n.) and P. hoelzeli (= P. kisi, syn. n.). The synonymy of P. poecilus with P. affinis and the subspecific status of P. affinis komareki are confirmed. One species, Poecilimon jablanicensis, sp. n., is described as new to science. A tabulated key, lists and maps of all known localities and oscillograms of the songs of all the species in this group are presented. The phylogenetic relationships and evolutionary trends in the Poecilimon ornatus group are discussed.

The development of sexual differences in body size in Odonata in relation to mating systems

Martin-Alejandro SERRANO-MENESES, Mónica AZPILICUETA-AMORÍN, Tamás SZÉKELY, Alex CÓRDOBA-AGUILAR

Eur. J. Entomol. 104 (3): 453-458, 2007 | DOI: 10.14411/eje.2007.065

Adult body size is the result of important environmental, maternal and/or genetic effects acting on animals during development. Here we investigate how sexual size dimorphism (SSD) develops in seven species of Odonata: Anax imperator, Cordulegaster boltonii, Onychogomphus uncatus, Oxygastra curtisii (Anisoptera), Cercion lindeni, Ischnura graellsii and Platycnemis acutipennis (Zygoptera). SSD of both the last larval and adult stages of the same individuals, which were reared under laboratory conditions, was measured. The aims were to investigate (i) whether SSD develops during the larval stage, (ii) the direction of larval and adult SSD, and (iii) whether the direction of adult SSD can be predicted by the mating system of a given species (e.g. males of territorial species being larger than females and the opposite for non-territorial species). We found that although larval differences in size may be present between the sexes, these are not necessarily shown in the adult stage (they may change or disappear). Also, the mating system was not related to patterns of adult SSD. Differences in SSD in larvae may be caused by differential use of resources via differential niche-utilisation or sex-specific growth patterns. We highlight the fact that sexual selection favouring large male size and fecundity selection, which selects for large females may be acting on the observed patterns in SSD in adults.

Survival and developmental characteristics of the predatory bug Orius similis (Hemiptera: Anthocoridae) fed on Tetranychus cinnabarinus (Acari: Tetranychidae) at three constant temperatures

Shi-Chang ZHANG, Fen ZHU, Xia-Lin ZHENG, Chao-Liang LEI, Xing-Miao ZHOU

Eur. J. Entomol. 109 (4): 503-508, 2012 | DOI: 10.14411/eje.2012.063

Developmental characteristics of the predatory bug Orius similis fed on Tetranychus cinnabarinus were investigated at three constant temperatures (25, 28, and 31°C) under laboratory conditions (75±5% relative humidity and a 14L : 10D photoperiod). The survival of nymphs was highest at 28°C (75.57%) and at this temperature female adults O. similis had the longest oviposition period (21.1 d), the greatest fecundity (40.3 eggs) and the highest potential intrinsic rate of increase (rm: 0.108 d-1). These results suggest that O. similis can maintain greater population densities at 28°C than at the other temperatures tested. In addition, the functional response indicates that the attack rate of O. similis (1.04) and the maximum prey capacity (30.7 spider mites per bug in 24h) are greatest at 28°C. The results of this study provide useful information on the biology and time when to release O. similis in order to reduce the abundance of T. cinnabarinus in cotton fields.

Two ways of finding a host: A specialist and a generalist parasitoid species (Hymenoptera: Chalcidoidea: Pteromalidae)

Ralph S. PETERS

Eur. J. Entomol. 108 (4): 565-573, 2011 | DOI: 10.14411/eje.2011.073

Two closely related parasitoid wasp species with different host specificities were used for experimental studies on the biology of host finding, a crucial element of parasitoid life history: The habitat and host specialist Nasonia vitripennis and the habitat and host generalist Dibrachys microgastri (Chalcidoidea: Pteromalidae). The host finding parameters tested included reaction to olfactory cues, aspects of locomotor activity, ability to locate hidden hosts and day-night-activity. The results revealed distinct interspecific differences that match the respective host and habitat ranges of the two species. In N. vitripennis host finding is dominated by olfactory reaction to hosts and host habitat, i.e., fly puparia and birds' nests. In D. microgastri olfactory cues have only a minor role. Its host finding is characterized by rapid searching at random. Both species are able to locate hidden hosts. Although still incomplete, these insights into host finding by two parasitoid species with different life history strategies indicate they can be characterized by specific combinations of behavioural host finding features.

Physiology of heartbeat reversal in adult Drosophila melanogaster (Diptera: Drosophilidae)

Karel SLÁMA

Eur. J. Entomol. 107 (1): 13-31, 2010 | DOI: 10.14411/eje.2010.002

Heartbeat patterns were monitored in the living bodies of decapitated adult flies using several electrocardiographic methods (pulse-light optocardiography, thermocardiography, strain-gauge cardiography). Unlike other insect species, in which there is a peristaltic segmental propagation of cardiac contractions, Drosophila uses extremely efficient synchronic cardiac contractions. The rate of synchronic cardiac pulsation, which is characterized by simultaneous propagation of anterograde systolic contractions along all the segments of the heart, is relatively fast (~ 4 Hz at room temperature). This pulsation is used mainly for the vigorous pumping of haemolymph into the head and thorax through a narrow elastic tube, the aorta (anterograde I heartbeat). In addition, this synchronic pulsation is also used to enhance the circulation of haemolymph throughout the abdominal body cavity (anterograde II heartbeat). The switch between thoracic (anterograde I) and abdominal (anterograde II) haemolymph circulation is regulated by periodically alternating, tetanic contractions and relaxations of the conical heart chamber (ventricle). In the latter there is a pair of slit-like apertures, which are closed or opened by contraction or relaxation of the organ, respectively. During contraction of the conical chamber, the apertures are tightly constricted for several seconds and haemolymph is pumped forwards into the aorta (anterograde I heartbeat). Conversely, during relaxation of the conical chamber, the apertures are wide open for a few seconds, haemolymph leaves the heart and leaks out through open apertures and circulates from the tail to the base of the abdomen. The backward oriented, retrograde heartbeat recorded in other insects, has a lower frequency (1 to 2 Hz), occurs in Drosophila only sporadically and usually in the form of individual or twinned systolic peaks of large amplitude. Unlike the synchronic nature of the anterograde I and II cardiac contractions, propagation of the relatively slow retrograde heartbeat is by peristalsis. The newly discovered, compact ventricle with atrium and synchronic functioning of the insect heart shows structural and functional analogies with the functioning of the human heart.

Morphology of the spermatheca in the Cydnidae (Hemiptera: Heteroptera): Bearing of its diversity on classification and phylogeny

Dominique PLUOT-SIGWALT, Jerzy A. LIS

Eur. J. Entomol. 105 (2): 279-312, 2008 | DOI: 10.14411/eje.2008.038

Cuticular parts of the spermatheca and associated vaginal structures (chiefly the ring sclerites of the parietovaginal glands) have been examined and compared in 190 cydnid species representing 65 genera and all five subfamilies currently recognized in the family (Amnestinae, Cephalocteinae, Cydninae, Garsauriinae, Sehirinae). Four species belonging to genera formerly included within the Cydnidae (Dismegistus, Parastrachia, Thaumastella, Thyreocoris) were also examined. Morphology of the three main parts of the spermatheca [seminal receptacle (distal bulb), intermediate part (pump apparatus), spermathecal duct] is described. Four main types of spermathecae can be recognized from the distal receptacle and the intermediate part: the amaurocorine type (in Sehirinae: Amaurocorini), amnestine type (in Amnestinae), garsauriine type (in Garsauriinae), and "cydnoid" type (in Cephalocteinae + Cydninae: Cydnini, Geotomini + Sehirinae: Sehirini). No synapomorphy of these types was found which suggests that the currently conceived Cydnidae are not monophyletic. Moreover, out of these four types only the "cydnoid" is typically pentatomoidean due to the presence of an intermediate part usually well delimited by two flanges and having always an unsclerotized flexible zone as well as two internal cuticular structures (septum and fretum) partly obstructing the lumen. The simple tubular amaurocorine type is unusual and aberrant within all Pentatomoidea. The amnestine and garsauriine types display some similarities with taxa outside the Pentatomoidea, especially with some lygaeoid or coreoid spermathecae, mainly in the structure of the intermediate part not delimited proximally (absence of flanges) and devoid of the flexible zone. Within the "cydnoid" type, six spermathecal facies can be characterized principally according to the shape of both the apical reservoir along with the intermediate part, and the differentiations of the spermathecal duct. It has been impossible to find any synapomorphy for all species and for the six facies belonging to the "cydnoid" type of spermatheca. We suggest that the Cydnidae as defined presently are probably a polyphyletic group; moreover its main "cydnoid" branch, called by us Cydnidae sensu stricto (Cephalocteinae + Cydninae + Sehirinae: Sehirini) seems to be relatively recent among the Pentatomoidea. Nishadana and Nishocoris are transferred from Garsauriinae back to Cydninae: Cydnini and the tribe Amaurocorini (Sehirinae) is upgraded to a separate subfamily Amaurocorinae stat. nov. Moreover, we regard the Geotomini and the Sehirini both as non-monophyletic and we indicate that by appending them sensu lato (Geotomini "s. l.", Sehirini "s. l.")

The head morphology of Ascioplaga mimeta (Coleoptera: Archostemata) and the phylogeny of Archostemata

Thomas HÖRNSCHEMEYER, Jürgen GOEBBELS, Gerd WEIDEMANN, Cornelius FABER, Axel HAASE

Eur. J. Entomol. 103 (2): 409-423, 2006 | DOI: 10.14411/eje.2006.055

Internal and external features of the head of Ascioplaga mimeta (Coleoptera: Archostemata) were studied with micro X-ray computertomography (µCT) and nuclear magnetic resonance imaging (NMRI). These methods allowed the reconstruction of the entire internal anatomy from the only available fixed specimen. The mouthparts and their associated musculature are highly derived in many aspects. Their general configuration corresponds to that of Priacma serrata (the only other archostematan studied in comparable detail). However, the mandible-maxilla system of A. mimeta is built as a complex sorting apparatus and shows a distinct specialisation for a specific, but still unknown, food source. The phylogenetic analysis resulted in the identification of a new monophylum comprising the genera [Distocupes + (Adinolepis +Ascioplaga)]. The members of this taxon are restricted to the Australian zoogeographic region. The most prominent synapomorphies of these three genera are their derived mouthparts.

Scorpion reproductive strategies, allocation and potential; a partial review

Michael R. WARBURG

Eur. J. Entomol. 108 (2): 173-181, 2011 | DOI: 10.14411/eje.2011.023

Most scorpion species are iteroparous, breeding more than once during their life. Some of these species are parthenogenetic. The other reproductive strategy (RS) semelparity, when scorpions breed only a single time during their life, is rare and has been documented only once. The mass allocated by the female to produce either a litter or a single offspring is the reproductive allocation (RA). It is difficult to calculate RA since the difference in female mass before and after parturition is difficult to obtain. In addition, the litter size is hardly ever accurate because of maternal cannibalism. An attempt was made to calculate RA in Nebo hierichonticus (E. Simon, 1872). Based on litter size, on breeding frequency and on longevity of the female, it is possible to estimate the reproductive potential (RP). These aspects of scorpion reproduction are reviewed and the difficulties involved in this study are discussed.

A review of Fennoscandian arthropods living on and in snow

Sigmund HÅGVAR

Eur. J. Entomol. 107 (3): 281-298, 2010 | DOI: 10.14411/eje.2010.037

A permanent snow cover for several months is typical for large parts of Norway, Sweden and Finland. Snow layers thicker than about 20 cm insulate the soil surface and stabilize the ground temperature close to 0°C. Many ground-living invertebrates are active at this temperature in the subnivean air space. From this "base camp", some invertebrates migrate upwards to use the snow as a substrate. The intranivean fauna consists of springtails (Collembola) and mites (Acari) that are small enough to move within the narrow pores between snow crystals. The supranivean fauna consists of various invertebrates that are active on the snow surface. Some of them are Collembola that have migrated through the snow layers. However, most of them are larger insects and spiders which migrate between the subnivean and supranivean habitats following air channels which are naturally created along tree stems, bushes etc. penetrating the snow. Likewise, certain Chironomidae and Plecoptera, hatching from winter-open rivers and brooks, are active on the snow surface. The supranivean arthropod fauna has the following characteristics: 1. It is a weather dependent assemblage of species, coming and going with changes in air temperature, cloud cover, and wind. Below ca. -6°C animals are absent, but at temperatures around or above zero, many groups can be simultaneously active on snow. 2. The snow surface fauna shows phenological changes throughout the winter, as certain species and groups are mainly active during certain months. 3. Some invertebrates are highly specialized and take advantage of the snow surface as an arena in their life cycle. Examples are Hypogastrura socialis (Collembola), and the two wingless insects Chionea sp. (Diptera: Limoniidae) and Boreus sp. (Mecoptera). They use the smooth snow surface for efficient migration. Chionea sp. and Boreus sp. lay their eggs during the snow-covered period, while H. socialis migrates to create new colonies. The cold tolerant spider Bolephthyphantes index is unique in constructing webs in small depressions on the snow, to catch migrating Collembola. Various adaptations for using the snow as a substrate are discussed. Besides physiological and morphological adaptations, snow surface arthropods show special behavioural adaptations. Most conspicuous is the ability of several Collembola species to navigate during migration, using the position of the sun for orientation. Furthermore, in Collembola and Mecoptera, jumping as an original mechanism to escape predators has independently evolved into a migrating mechanism. An evolutionary potential exists for more invertebrate groups to take advantage of snow as a substrate in their life cycle. For instance, several more cold tolerant spiders might evolve the ability to catch migrating Collembola on snow.

Review of the genus Agnippe (Lepidoptera: Gelechiidae) in the Palaearctic region

Oleksiy BIDZILYA, Houhun LI

Eur. J. Entomol. 107 (2): 247-265, 2010 | DOI: 10.14411/eje.2010.033

The genus Agnippe Chambers, 1872 in the Palaearctic Region is revised. Sixteen species are recognized as valid. Three new synonyms are established: A. conjugella Caradja, 1920 = A. haberlandii Amsel, 1961 syn. n., A. lunaki Rebel, 1941 = A. penicillata Amsel, 1961 syn. n., A. kuznetzovi Lvovsky & Piskunov, 1989 = A. zhengi Li, 1993 syn. n. Four new species are described: A. echinuloides sp. n. (S Ural, Tuva, Transbaikalia, Mongolia), A. turanica sp. n. (Uzbekistan, Kazakhstan), A. deserta sp. n. (Uzbekistan) and A. separatella sp. n. (S Iran). Description of all the species and an identification key are presented, accompanied by illustrations of the adults, and male and female genitalia.

Descriptions of larvae of Megadytes (Coleoptera: Dytiscidae: Dytiscinae): The hypothesis of monophyletic origin revisited

Mariano C. MICHAT

Eur. J. Entomol. 103 (4): 831-842, 2006 | DOI: 10.14411/eje.2006.114

The three larval instars of Megadytes (Paramegadytes) glaucus (Brullé, 1838) and the third-instar larvae of M. (Bifurcitus) magnus Trémouilles & Bachmann, 1980 and M. (Trifurcitus) robustus (Aubé, 1838) are described and illustrated for the first time, with particular emphasis on the morphometry and chaetotaxy. A key to the subgenera of Megadytes Sharp, 1882 is presented. In a cladistic analysis of third-instar larval characters, Megadytes is resolved as non-monophyletic; the species of Cybistrini studied, except those included in the subgenus Trifurcitus Brinck, 1945, share three synapomorphies: (i) medial projection of frontoclypeus truncate apically, with many apical setae directed forwards; (ii) lateral projections of frontoclypeus project forwards, not flattened; and (iii) median process of prementum rounded apically. The clade composed of the subgenera Megadytes s. str., Paramegadytes Trémouilles & Bachmann, 1980 and Bifurcitus Brinck, 1945 along with Cybister lateralimarginalis (De Geer, 1774) is well supported by three synapomorphies: (i) head capsule subrectangular and (ii) distal third of mandible more strongly projected inwards, (iii) with a ring of long, hair-like setae. The two species of the subgenus Paramegadytes have bilobed lateral projections on the frontoclypeus. Megadytes (M.) marginithorax (Perty, 1830) is characterized by the very narrow notches between the medial and lateral projections of frontoclypeus. No synapomorphies were discovered to group together the two species of the subgenus Bifurcitus.

Cloning and pattern of expression of trehalose-6-phosphate synthase cDNA from Catantops pinguis (Orthoptera: Catantopidae)

Bin TANG, Hui-Zhen ZHENG, Qi XU, Qi ZOU, Guang-Jun WANG, Fan ZHANG, Shi-Gui WANG, Ze-Hua ZHANG

Eur. J. Entomol. 108 (3): 355-363, 2011

Trehalose is not only an important disaccharide, but also a key stress resistance factor in the development of many organisms, including plants, bacteria, fungi, and insects. To study the potential function of trehalose in development and behaviour, cDNA for a trehalose-6-phosphate synthase from Catantops pinguis (CpiTPS) was cloned and sequenced. Results revealed that the CpiTPS cDNA sequence contains an open reading frame of 2430 nucleotides encoding a protein of 809 amino acids with a predicted molecular weight of 91.13 kDa and a pI value of 6.25. Northern blot and RT-PCR analyses showed that CpiTPS mRNA expression was high in the fat body and testes, ovaries, Malpighian tubules, brain, trachea, rectum, and posterior extensor of C. pinguis. Northern blotting revealed that CpiTPS mRNA was expressed in the fat body at different developmental stages and was present at a high level in first instar larvae and adults. The results demonstrate that CpiTPS is a key gene in C. pinguis development.

The quality of aphids as food for generalist predators: implications for natural control of aphids

Søren TOFT

Eur. J. Entomol. 102 (3): 371-383, 2005 | DOI: 10.14411/eje.2005.054

The paper reviews existing data on the food quality of cereal aphids for generalist predators. Data are presented for spiders, harvestmen, carabid and staphylinid beetles, cockroaches, ants and one species of bird. All results agree that cereal aphids are low-quality food compared to alternative prey types (in most studies fruit flies). This is associated both with a low consumption capacity for aphids and a low utilization efficiency of the aphid food. A pure aphid diet allows full juvenile development in only a few species. Aphids as part of mixed diets can have negative, neutral or positive effects, which depends on the quality of the remaining diet. The low consumption capacity for aphids is due to the development of a specific feeding aversion. Genetic variation in the ability to tolerate aphids has been documented, indicating that predators may be able to adapt to a higher proportion of aphids in the diet in areas where outbreaks are frequent. A consequence of these findings is that predator populations rely on alternative prey (e.g. Collembola and Diptera) for maintenance and reproduction, and are probably unable to benefit nutritionally from an aphid outbreak. The low food quality of aphids to generalist predators explains why generalist and specialist predators have widely different roles in aphid biocontrol, but does not rule out that under some conditions the generalists may be able to inhibit aphid population growth sufficiently to prevent an outbreak, as field experiments have indicated. Simulation modelling shows that a low consumption capacity for aphids has little influence on the ability to prevent aphid population increase at low aphid immigration rates, but a great influence at high aphid immigration rates. Modelling also indicates that there may be an optimal availability of high-quality alternative prey that maximizes the impact of generalist predators on aphid population growth.

A novel association between Aphaenogaster subterranea (Hymenoptera: Formicidae) and the nymphs of Reptalus panzeri (Hemiptera: Cixiidae)

Gábor LŐRINCZI

Eur. J. Entomol. 109 (4): 509-515, 2012 | DOI: 10.14411/eje.2012.064

The nymphs of the cixiid planthopper, Reptalus panzeri (Löw, 1883), were found cohabiting with the myrmicine ant Aphaenogaster subterranea (Latreille, 1798) in a sub-Mediterranean oak forest in mid-western Hungary. Except for a few cases, nymphs were recorded only in the nests of A. subterranea, or were recorded with foragers of this ant from neighbouring colonies. Adult planthoppers were also found in nests of A. subterranea in the emergence period. Neither field nor laboratory studies revealed direct or unambiguous interactions between this ant and the planthopper nymphs that would indicate a trophobiotic relationship, however the fact that nymphs do not try to escape from the ants, which do not attack the nymphs, indicates some kind of mutualistic relationship between them. The main food plant of R. panzeri nymphs in this habitat is likely to be the roots of manna ash (Fraxinus ornus).

Praon volucre (Hymenoptera: Braconidae: Aphidiinae), a natural enemy of Macrosiphum euphorbiae (Hemiptera: Aphididae): Life table and intrinsic rate of population increase

Juracy Caldeira LINS Jr., Vanda Helena Paes BUENO, Diego Bastos SILVA, Marcus Vinicius SAMPAIO, Joop C. van LENTEREN

Eur. J. Entomol. 108 (4): 575-580, 2011 | DOI: 10.14411/eje.2011.074

Life table data of natural enemies are often used to understand their population dynamics and estimate their potential role in the biological control of pests. Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae) is an important pest of several crops and its intrinsic rate of population increase (rm) is 0.282 at 22°C. The life table parameters (immature mortality, developmental time, sex ratio of emerging adults, fecundity and longevity) of Praon volucre (Haliday) (Hymenoptera: Braconidae: Aphidiinae) parasitizing M. euphorbiae were estimated in a climatic chamber at 22 ± 1°C, RH 70 ± 10% and 12 h photophase. Immature mortality was 8.2%, developmental time of males and females was 13.9 and 14.4 days, respectively, and the sex ratio was 0.55 (= fraction of females). Parasitoid fecundity was 504 eggs and longevity 11 days. The net rate of reproduction (R0) was 207.5 females and the intrinsic rate of population increase (rm) 0.281 females/female/day. The time for doubling the population (TD) was 2.45 weeks. P. volucre has a population growth rate similar to that of its host M. euphorbiae and might therefore be a good candidate for the biological control of this aphid.

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