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Results 481 to 510 of 1442:

Biology of Rhembobius quadrispinus (Hymenoptera: Ichneumonidae): Pupal parasitoid of saprophagous species of syrphids (Diptera: Syrphidae)

Pilar HURTADO, Celeste PÉREZ-BAÑÓN, Santos ROJO

Eur. J. Entomol. 111 (3): 379-385, 2014 | DOI: 10.14411/eje.2014.040

Little is known about the life cycle of Rhembobius parasitoids (Hymenoptera: Ichneumonidae). Known host records are mainly from saprophagous species of hoverflies of the tribe Eristalini (Diptera: Syrphidae), whose larvae develop in a wide range of aquatic and semi-aquatic breeding sites that are rich in microbial decay. We present an account of the biology and important details of the life cycle of the pupal parasitoid R. quadrispinus in both natural and controlled conditions. Host suitability, the influence of host pupal age and age of the female parasitoid on her production of progeny was evaluated in laboratory tests. Our results showed that the percentage of pupae of E. tenax that were parasitized by R. quadrispinus decreased as pupae matured, and the optimal age for successful parasitism ranged from 1 to 3 days. This biological information could be useful in the biological control of anthropophilic saprophagous eristalines that can act as potential mechanical vectors of pathogens on farms.

Temporal variations in the life-cycles of aphids (Sternorrhyncha: Aphididae) and their coccinellid predators

Mohamed El Fodhil AROUN, Bahia DOUMANDJI-MITICHE, Daniel PETIT, Zahr-Eddine DJAZOULI

Eur. J. Entomol. 112 (3): 432-439, 2015 | DOI: 10.14411/eje.2015.060

Aphids are either monoecious living either on trees or herbaceous plants, or heteroecious, which involves host alternating between a tree (primary host) and a herbaceous plant (secondary host). We described the temporal variations in abundance and richness of aphids in an Algerian orchard, over a 6 month period. We recorded the choice of basin colour, the relative height of traps, and monthly Barycenter of winged populations. We also recorded temporal variations in the structure of ladybird communities. Tree-living species of aphids are the last to be caught with most caught by the yellow traps, possibly because of the predominant greenness of the vegetation in April. Most were also caught by high traps. Their phenology coincides with that of the second peak of ladybirds. In contrast, the phenology of species of aphids living on herbaceous plants differs greatly, which reflects their host plant diversity. In March relatively more of these aphids were caught by the green traps, possibly because at that time the ground was not yet covered by vegetation. Early and late species of aphids are at greater risk of being attacked by ladybirds as they are also most active early and late in the season. The highest catches of the heteroecious species of aphids were recorded in the middle of the trapping period and between those of the two groups of monoecious species of aphids. The adaptive significance of the differences in the behaviour and ecology of the aphids in the three groups is discussed.

Identification of heat shock protein genes hsp70s and hsc70 and their associated mRNA expression under heat stress in insecticide-resistant and susceptible diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

Lin Jie ZHANG, Kuan Fu WANG, Yu Pu JING, Hua Mei ZHUANG, Gang WU

Eur. J. Entomol. 112 (2): 215-226, 2015 | DOI: 10.14411/eje.2015.039

To gain further insight into the molecular features of the ubiquitous Hsp70 family of conserved heat shock proteins, total nine full-length cDNA sequences of inducible hsp70s (Px-hsp69-1, -2a, -2b, -3, -4, Px-hsp72-1a, -1b, -2 and -3) and one constitutive hsc70 (Px-hsc70(C)) were isolated and characterized in the diamondback moth (DBM), Plutella xylostella, collected from Fuzhou, China. The nine Px-hsp70s cDNAs encoded the protein of between 629-669 amino acids with molecular weight ranging from 69.00-72.58 kDa and were derived from four hsp70 genes in the genome of DBM. The Px-hsc70(C) cDNA contained 1,953 bp of open reading frame (ORF), which produced a putative protein comprising 650 amino acids with a calculated molecular weight of 71.18 kDa. Whether in adults or larvae of chlorpyrifos-resistant (RR) and chlorpyrifos-susceptible (SS) strains of DBM, the basal level (at 25°C) of Px-hsc70(C) mRNA expression was high, but no significant up-regulation expression was found under heat stress. However, heat stress facilitated up-regulation expressions of Px-hsp70s, and SS DBM displayed higher up-regulation expression of Px-hsp70s than RR DBM. We suggest that higher up-regulation expression of Px-hsp70s in SS DBM is probably involved in their higher thermal tolerance.

Longevity of starved bumblebee queens (Hymenoptera: Apidae) is shorter at high than low temperatures

Salla-Riikka VESTERLUND, Jouni SORVARI

Eur. J. Entomol. 111 (2): 217-220, 2014 | DOI: 10.14411/eje.2014.035

Northern bumblebees (Hymenoptera: Apidae) with annual lifecycles depend both on energy stores remaining in their fat body after diapause and a few spring flowering plants. Most temperate bumblebees emerge gradually over several months after winter depending on the species and within species on the location of the overwintering chamber (hibernaculum). Weather can either delay or promote emergence and nectar resources are needed to fuel flight at low ambient temperatures to find a nest site. Several phoretic mites use queens for transportation and have synchronized life cycles with their host species. Their presence on the body of bumblebees is usually harmless but can become harmful when the number of mites increases to hundreds per individual bee. High numbers of mites on queens may also indicate the queens are in poor condition. The effect of temperature and mite load on the time for which queens can survive (d) during a 25-day period of starvation were determined using newly emerged spring queens of B. lucorum. Queens collected from various locations in SW Finland were divided into four groups taking into account their initial load of Parasitellus fucorum mites: (A) 15°C and provided with only water; (B) 24°C and provided with only water; (C) 15°C and provided with pollen and nectar; (D) 24°C and provided with pollen and nectar. There were mites on 65% (50 out of 77) of the queens. All of the fed queens survived and starved queens died, with those kept at 24°C dying approximately 8 days before those kept at 15°C. Queen weight or mite load had no effect on the length of the period for which they survived and there was no difference in the weights of the queens in the different mite load classes. Asynchrony between plants and insect as well as increased frost damage due to climate change may affect nectar availability in spring. Therefore, the survival and long term viability of bumblebee populations should be monitored during variable spring conditions.

Form, function and evolutionary significance of stridulatory organs in ant nest beetles (Coleoptera: Carabidae: Paussini)

Andrea DI GIULIO, Simone FATTORINI, Wendy MOORE, James ROBERTSON, Emanuela MAURIZI

Eur. J. Entomol. 111 (5): 692-702, 2014 | DOI: 10.14411/eje.2014.083

Stridulatory organs in the myrmecophilous carabid beetle tribe Paussini have long been recognized and used as a defining character of some genera and higher level taxa, however their morphology has only roughly been described. Here, we describe the fine morphology of Paussini stridulatory organs using scanning electron (SEM) and focused ion beam (FIB) microscopy. Within this tribe, there are three types of stridulatory organs, each with different positions of the scraper (plectrum) and file (pars stridens). Type I (abdomen-femur type) is located on the abdomen (scraper) and metafemur (file) in the subtribe Paussina (sensu Geiselhardt et al., 2007, Naturwissenschaften 94: 871-894). Type II (thorax-femur type) and Type III (femur-thorax type) are located on the mesothorax and mesofemur in two different genera of the subtribe Platyrhopalina, however in Euplatyrhopalus the scraper is located on the mesothorax and the file is located on the mesofemur (Type II), whereas in the genus Platyrhopalopsis the structures are reversed in that the file is located on the mesothorax and the scaper is located on the mesofemur (Type III). The independent evolution of three types of stridulatory organs in three lineages of Paussini suggests that acoustical communication has played an important role in the evolution of ant nest beetles. While the roles of stridulation in this group remain speculative, we verified that all three types of stridulatory organs are present in both sexes and are similar to stridulatory organs known in their host ants which also use stridulation as a method of communication. We discuss the possibility that the beetles stridulation could (1) facilitate their exploitation of ant colonies, and (2) be involved in mate recognition and courtship.

Development, reproduction, host range and geographical distribution of the variegated caper bug Stenozygum coloratum (Hemiptera: Heteroptera: Pentatomidae)

Shahar SAMRA, Murad GHANIM, Alex PROTASOV, Zvi MENDEL

Eur. J. Entomol. 112 (2): 362-372, 2015 | DOI: 10.14411/eje.2015.041

The variegated caper bug (CB) Stenozygum coloratum (Klug, 1845) is common in the Eastern Mediterranean region and a minor agricultural pest. CB eggs were recently shown to serve as alternative hosts for Ooencyrtus pityocampae Mercet, 1921, an important natural enemy of the pine processionary moth (PPM) Thaumetopoea wilkinsoni Tams, 1924 (Lepidoptera: Notodontidae). In this study various aspects of the life history of CB were studied, including its distribution, host range, development, reproduction and ability to develop on various cultivated species of plants. CB occurs in almost all areas and habitats in Israel, except in the coldest regions, attacking several caper species (Capparis spp.). When reared on Capparis zoharyi at 25°C, one generation lasted 6 weeks and females laid a single 12-egg cluster every 3 days. Decreases in temperature, but not changes in day length, terminated reproductive activity. CB nymphs survived for up to three months, or even completed their development, on some agricultural plants. However, reproductive activity was initiated only if adults were fed capers. These findings emphasize the importance of capers in the CB life cycle and account for why other plants are rarely attacked. These plants may serve as a temporary refuge for CB when capers are scarce or unsuitable, mainly late in the season. Morphology of developmental stages, egg deposition, cannibalistic behaviour, sex ratio and effects of temperature on egg production were also studied. The possibility of using CB for enhancing the biological control of PPM is discussed.

Modification of the rotating model method for studying the sexual discriminative abilities of butterflies (Lepidoptera)

Tsuyoshi TAKEUCHI

Eur. J. Entomol. 112 (4): 860-861, 2015 | DOI: 10.14411/eje.2015.078

Recently, Imafuku & Kitamura (Eur. J. Entomol. 112, 2015: 328-333) succeeded in inducing males of two territorial butterflies, Chrysozephyrus smaragdinus and Neozephyrus japonicus, to respond to wing models by rotating the models. Based on the results of two-choice tests in which males stayed longer within 50 mm of the female model than the male model the authors claim that males of both of these butterflies identify females using the patterns on the wings. I think this study provides a new method for studying the discriminative abilities of butterflies. In contrast to static models, however, butterflies attracted to rotating models do not land on the models but remain at some distance from the moving models. A close approach to a model, therefore, does not always reflect the animal's preference. I suggest a better way of using this method for testing the discriminative ability of butterflies.

Thermoregulation and the influence of body temperature on calling song parameters in Cicada orni (Hemiptera: Cicadidae)

Allen F. SANBORN, Paula C. SIMÕES, Polly K. PHILLIPS, José A. QUARTAU

Eur. J. Entomol. 108 (3): 365-369, 2011

Measurements of body temperature in the field demonstrate that Cicada orni Linnaeus regulates body temperature through behavioral mechanisms. Behavior is used to regulate body temperature to a range necessary for calling. As predicted, results showed a general decrease of echeme duration and an increase in inter-echeme interval with rising body temperature. However, no statistically significant correlations of body temperature for any of the variables studied were found, giving evidence that there is more variability in call parameters between individuals than any effect of body temperature.

Phylogeny of quill mites of the family Syringophilidae (Acari: Prostigmata) based on their external morphology

Maciej SKORACKI, Eliza GLOWSKA, Andre V. BOCHKOV

Eur. J. Entomol. 110 (4): 663-675, 2013

External morphological characters were used to reconstruct a phylogeny of the mite family Syringophilidae (Acariformes: Cheyletoidea), which are permanent parasites inhabiting the quills of bird feathers. A total of 53 syringophilid genera and 79 characters were included in the data matrix; maximum parsimony (MP) and Bayesian analyses (BA) were performed to determine their phylogenetic relationships. The consensus of unweighted MP trees was weakly resolved. Only four generic groups were recognized: Aulonastus + Krantziaulonastus (i) and (Creagonycha + Kethleyana) + (Megasyringophilus + Selenonycha) (ii) - both with low Bremer support (BS 1); the subfamily Picobiinae - Picobia, Calamincola, Columbiphilus (Neopicobia + Rafapicobia) (BS 12) (iii) and Psittaciphilus generic group - (Meitingsunes + Psittaciphilus) (Peristerophila + (Neoperisterophila + (Castosyringophilus + Terratosyringophilus))) (BS 2) (iv). BA revealed a consensus tree with a topology similar to MP. The two main groups recognized by MP, the subfamily Picobiinae and Psittaciphilus, both received the highest support of 1; while two other groups recognized by MP - Aulonastus + Krantziaulonastus and (Creagonycha + Kethleyana) + (Megasyringophilus + Selenonycha) received relatively low support of 0.73-74 and 0.76-77, respectively. The consensus of re-weighted MP trees was almost fully resolved but, the majority of the generic groups, excluding the Picobiinae and Psittaciphilus were supported by just a few non-unique synapomorphies with a high probability of homoplastic origin. The most intriguing result is the paraphyly of the Syringophilinae in respect to picobiines. The pattern of the re-weighted tree demonstrates only patches of parallel evolution at the level of syringophilid genera and bird orders. Perhaps horizontal shifts on phylogenetically distant hosts and colonization of quill (calamus) types other than primaries and secondaries were also important in the evolution of the syringophilids.

Does the prediction of the time of egg hatch of Thaumetopoea processionea (Lepidoptera: Notodontidae) using a frost day/temperature sum model provide evidence of an increasing temporal mismatch between the time of egg hatch and that of budburst of Quercus robur due to recent global warming?

Eiko WAGENHOFF, Annika WAGENHOFF, Rainer BLUM, Holger VEIT, Daniel ZAPF, Horst DELB

Eur. J. Entomol. 111 (2): 207-215, 2014 | DOI: 10.14411/eje.2014.030

Thaumetopoea processionea is a serious defoliator of oak and of medical concern whose abundance has consistently increased throughout Europe during the past two decades. This study validates a previously published frost day/temperature sum model for predicting time of egg hatch of this species using five years of recent field data from South-West Germany. This model proved satisfactory for predicting the time of egg hatch of T. processionea. Hence, the model was used to retrospectively predict the time of egg hatch of T. processionea in the Karlsruhe area, which indicates that the time of egg hatch has fluctuated over the past 130 years. In the last two decades, however, predicted time of egg hatch is much earlier than the long-term average due to the increase in winter and early spring temperatures. Comparison of predicted time of egg hatch of T. processionea and long-term records of the time of foliation of its common host Quercus robur revealed that in the study area the temporal advance in the timing of both events was similar. This is not in accordance with recently published research on spring-feeding folivores, which report a diverging trend in the timing of egg hatch and budburst of their host plants as a consequence of human-induced climate change.

Consequence of the transformation of a primeval forest into a managed forest for carabid beetles (Coleoptera: Carabidae) - a case study from Bia³owie¿a (Poland)

Jaros³aw SK£ODOWSKI

Eur. J. Entomol. 111 (5): 639-648, 2014 | DOI: 10.14411/eje.2014.088

A comparison was made of the number of species, species diversity and ecological traits of carabid beetle (Coleoptera: Carabidae) assemblages inhabiting Bia³owie¿a Primeval Forest (National Park) and adjacent managed Bia³owie¿a forest planted following clear-cutting of the primeval forest 80 years ago. Five pitfall traps were set in each plot in the primeval and managed forests in areas that differed in terms of humidity and soil fertility. The first hypothesis tested was that the type of stand (primeval vs. managed) has a greater effect on species diversity and life history traits of carabid assemblages than soil fertility or humidity. The second hypothesis tested was that a similar hierarchy of these factors affects the occurrence of particular species. It was demonstrated that the number of species in the primeval and managed forest sites did not differ significantly, but that mesic stands within these forests were more species-rich than boggy stands. However, the Shannon index for carabids was higher for the primeval stands. More species of carabids were recorded in the boggy primeval forest than boggy managed forest. The number of species was also higher in highly fertile than less fertile stands. These results indicate that the significant differences in the patterns of ecological traits among the assemblages studied depended mainly on humidity. This indicates the managed forest that was planted where a primeval stand was clear felled 80 years ago is a good quality habitat, which is a strong argument for protecting these stands.

Increase in dark morphs and decrease in size during a range extension of Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

Yasuko KAWAKAMI, Kazuo YAMAZAKI, Kazunori OHASHI

Eur. J. Entomol. 112 (2): 289-294, 2015 | DOI: 10.14411/eje.2015.029

The ladybird beetle Cheilomenes sexmaculata (Fabricius) is widely distributed throughout the intermediate latitudinal and equatorial regions. It exhibits elytral colour polymorphism with a geographical cline showing increased prevalence of melanic morphs with increasing latitude. Over the past 100 years, this species has extended its distribution towards higher latitudes in Japan because of climatic warming. In this study, long-term changes in the frequency of different morphs and adult body size of this species during this range extension were analyzed based on a survey of specimens in collections. First, we examined specimens collected from areas that were colonized (34-36°N) during the period of range extension (1949-1989) and when it ceased (1990-2005). Chronologically, both the proportions of melanic morphs increased and body size decreased significantly. Next, specimens were examined from newly colonized regions and the former range of distribution (32-34°N); these specimens were collected during period when range extension had ceased. In newly colonized regions, the frequency of melanic morphs was higher and the body size was smaller than in the former range of distribution. These two findings indicate that the smaller, melanic morphs may have undergone a positive-selection driven range extension to higher latitudes.

An optimized method for mass rearing the tiger-fly, Coenosia attenuata (Diptera: Muscidae)

Joana MARTINS, Célia MATEUS, Ana C. RAMOS, Elisabete FIGUEIREDO

Eur. J. Entomol. 112 (3): 470-476, 2015 | DOI: 10.14411/eje.2015.059

The tiger-fly Coenosia attenuata Stein (Diptera: Muscidae) is a predator that is currently thought to be a useful biological control agent in greenhouses, especially in the Mediterranean region. Here, we present a method for rearing this predator in the laboratory by feeding it on fungus gnats (fed on Pleurotus ostreatus fungus) and drosophilids (Diptera). Over the past two years, this method has been continuously used to successfully produce predators for bioecological studies in the laboratory. Rearing cages with one, five or 10 male-female pairs, either of laboratory or field origin, were compared using females that were either unmated and recently emerged, or mated and about 20 days old (post-emergence). We evaluated the following parameters: number of rearing cages in which adults emerged, number and sex ratio of emerged adults, period from the introduction of parental pairs into cages and the emergence of the first offspring adults, and the period over which emergence occurred in the cages. Based on our results and in order to minimize the space needed for the colony, cages should be stocked with ca. 10 parental pairs, either of field or laboratory origin, with at least some mated females about 20 days post emergence. We also found that the predator's rearing substrate in the cages is improved if coconut fibre is mixed with the soil. These findings will improve the efficiency of C. attenuata rearing, an important step if it is to be used as a biological control agent.

Relation between plant water status and Macrosiphum euphorbiae (Hemiptera: Aphididae) population dynamics on three cultivars of tomato

Anna R. RIVELLI, Vincenzo TROTTA, Irene TOMA, Paolo FANTI, Donatella BATTAGLIA

Eur. J. Entomol. 110 (4): 617-625, 2013

Deficit irrigation scheduling is used to increase the efficiency with which water is used in many crops including tomato, however a water deficit is predicted to favour phloem feeding insects. We tested if and how different cultivars of tomato grown under water deficit conditions affect the population growth of the aphid Macrosiphum euphorbiae. Three tomato cultivars (Scintilla, Beefmaster and Rio Grande) were used in the experiments. The results for three watering regimes were compared with those of a control, which was well watered every three days: stressed plants received one third of the water supplied to the control over each three-day interval (experiment 1); stressed plants received a gradually decreasing amount of water (100% at the first watering and then 80%, 60%, 50%, 40% and 20%) every three days (experiment 2); stressed plants received the same amount of water as the control but at longer intervals, that is when evident signs of wilting appeared (experiment 3). The results showed that water stress either enhanced, had an adverse effect or had no effect on aphid population growth, depending on the cultivar and watering regime. No difference was recorded in the population dynamics of M. euphorbiae feeding on Beefmaster tomato plants subjected to different levels of water stress. In the case of the cultivar Scintilla, live aphids were less abundant on stressed plants than on well watered ones in experiment 1 and 3 but not in experiment 2. The highest variability in aphid population dynamics on the plants grown under the different water stress protocols was recorded on the cultivar Rio Grande. In experiment 1, the initial peak in aphid numbers was higher on the water stressed plants than on the control and then decreased to lower numbers than on the control. In experiment 2, there were no differences in the numbers of aphids infesting stressed and control plants. In experiment 3, there were fewer aphids on stressed than on control plants after six days, as in experiment 1, but there was no initial peak in aphid numbers.

Population genetics and demographic history of guava fruit fly Bactrocera correcta (Diptera: Tephritidae) in northeastern Thailand

Chonticha KUNPROM, Piyamas NANORK SOPALADAWAN, Pairot PRAMUAL

Eur. J. Entomol. 112 (2): 227-234, 2015 | DOI: 10.14411/eje.2015.033

Bactrocera correcta (Bezzi) is among the most destructive fruit fly pests of the genus Bactrocera. This species infests 62 species of plants belonging 30 families, many of which are commercially important. In this study, the genetic structure, diversity and demographic history of B. correcta in Thailand were inferred from mitochondrial cytochrome c oxidase I (COI) sequences. High genetic diversity was recorded in the 171 samples collected from 15 locations. This was due largely to the existence of two divergent lineages (I, II) revealed by median joining (MJ) network analysis. Genetic structure analysis revealed an overall low level of genetic differentiation between populations suggesting that the flies can move freely across geographic regions. Because the host plants are commonly grown in Thailand, continuity of habitats is the factor most likely responsible for the genetic homogeneity. In addition, the recent population history could also be a factor that contributed to the overall low level of the genetic structure. Mismatch distribution analysis as well as Tajima's D and Fu's FS tests detected evidence of recent demographic expansion dating back to the end of the last glaciations.

Sociogenetic structure in nests of the mud dauber wasp Trypoxylon (Trypargilum) albitarse (Hymenoptera: Crabronidae)

Antonio C. BRAGATO BERGAMASCHI, Juliano DA COSTA ALMEIDA, Lucio A. DE OLIVEIRA CAMPOS, Marco A. DEL LAMA

Eur. J. Entomol. 112 (4): 722-727, 2015 | DOI: 10.14411/eje.2015.092

Trypargilum is a subgenus of solitary spider-hunting wasps whose males guard the nest, an unusual behaviour for male wasps. A male pairs with a female and copulates repeatedly with her during the nesting process, although females regularly copulate with satellite males, which employ an alternative reproductive strategy. The purpose of this paper was to determine the sociogenetic structure in twenty-nine nests of Trypoxylon albitarse sampled at six sites in Brazil. A total of 367 wasps were genotyped for eight species-specific polymorphic microsatellite loci. Genotypic segregation analyses were conducted to test whether the nests sampled were monogamic family groups. The results indicated that all the offspring in 12 of the 29 nests could be attributed to a single couple (genetic monogamy). Approximately 9% of the offspring probably resulted from extra-pair copulations and 3% of the total offspring were attributed to a second mother (usurpation by conspecific females, a form of intraspecific parasitism). The sequential replacement of parents throughout the nesting process indicates that the 29 nests analyzed included 35 family groups. Thus, our findings indicate that Trypoxylon albitarse has a predominantly monogamous genetic mating system, despite the social polygamy reported in previous studies.

Chromosome fusion polymorphisms in the grasshopper, Dichroplus fuscus (Orthoptera: Acrididae: Melanoplinae): Insights on meiotic effects

Alberto TAFFAREL, Claudio J. BIDAU, Dardo A. MARTÍ

Eur. J. Entomol. 112 (1): 11-19, 2015 | DOI: 10.14411/eje.2015.010

Robertsonian fusions account for many of the changes in the evolution of the orthopteran karyotype; in their origin, a centric fusion is involved between two acro-telocentric chromosomes, forming a single bi-armed chromosome. It is usual for these rearrangements to be associated with profound changes in meiosis, such as modification in frequency and distribution of chiasmata. Dichroplus fuscus is a South American grasshopper with a wide distribution. In this work we analyzed nine populations from Misiones Province, north-eastern Argentina. This species presents a standard karyotype of 2n = 23/24 (♂/♀) with all chromosomes acro-telocentric and an X0/XX chromosomal sex determining mechanism. This standard karyotype has been modified by the occurrence of two Robertsonian fusions involving chromosomes 1/3 and 2/4; values of fusions per individual (fpi) show a significant increase in the presence of karyotypic polymorphisms towards southern populations. In individuals showing chromosomal rearrangements, we observed a clear redistribution of chiasmata towards distal positions; significant differences were noted between Robertsonian homozygotes (Ho) and heterozygotes (Ht) for chromosomes arms L1 and M3, although this was not the case between Ho and Ht for chromosome arms L2 and M4. With regard to the orientation of trivalents, values obtained for non-convergent orientation were low.

Effects of environmental factors on the regulation of egg diapause in the walking-stick insect, Ramulus irregulariterdentatus (Phasmatodea: Phasmatidae)

Hiroyuki YAMAGUCHI, Keiji NAKAMURA

Eur. J. Entomol. 112 (1): 35-40, 2015 | DOI: 10.14411/eje.2015.011

Environmental factors that regulate egg diapause in the walking-stick insect, Ramulus irregulariterdentatus, were studied. Insects collected in fields at Okayama, Japan soon after hatching in spring were reared under constant laboratory conditions. After adult emergence, their eggs were placed outdoors or incubated under constant laboratory conditions. Most eggs kept at 15 or 20°C hatched more than 100 days after oviposition. At 25°C, however, many eggs remained in diapause throughout the experimental period although a small number hatched slightly earlier than those kept at the lower temperature. The maternal photoperiod affected the egg period at 20 and 25°C; eggs from females reared under short day conditions hatched significantly earlier. A low temperature of 10°C shortens diapause development, whereas 5°C did not have a clear effect on time to hatching. When eggs of females reared under long day conditions were placed outdoors from June to early July, most hatched the next spring. On the other hand, eggs of females reared under short day conditions hatched before winter if they were laid before mid-July. The short day eggs laid in August and September hatched successfully the following April, and there was a positive correlation between the date of oviposition and time of hatching. It is concluded that low temperatures in mid-winter do not terminate diapause development. The results revealed that both maternal regulation of diapause intensity and the rate of diapause development play an important role in maintaining a monovoltine life cycle in Ramulus irregulariterdentatus.

Characterisation of sixteen additional polymorphic microsatellite loci for the spreading but locally rare European butterfly, Brenthis ino (Lepidoptera: Nymphalidae)

Christophe LEBIGRE, Camille TURLURE, Nicolas SCHTICKZELLE

Eur. J. Entomol. 112 (2): 389-392, 2015 | DOI: 10.14411/eje.2015.047

Whilst the overall geographic range of the lesser marbled fritillary, Brenthis ino (Rottemburg, 1775), is currently expanding, this species is patchily distributed at a local spatial scale due to its use of flower rich semi-natural meadows and the aggregated distribution of its host plant. Therefore, understanding the dispersal patterns of this butterfly and the effect of increasing fragmentation of the landscapes in central and Western Europe on its population dynamics is key to determining whether this patchy distribution can lead to metapopulation structuring and dynamics. One way to determine the degree to which local populations are isolated from one another is to use high resolution molecular genetic markers and thence quantify gene flow and genetic drift. Eleven microsatellite loci have previously been developed for this species, but six showed evidence of null alleles, effectively violating key assumptions of the models used to infer gene flow. We therefore developed a set of new primer pairs to amplify a suite of 16 highly polymorphic microsatellite loci (number of alleles ranged from 2-30) of which nine were found to conform to the Hardy-Weinberg's expectations, whilst at the same time not showing any clear signature for the presence of null alleles. We further describe how these primers were optimized for landscape and metapopulation genetics studies in Belgian Ardenne.

Tuta absoluta (Lepidoptera: Gelechiidae): Thermal requirements and effect of temperature on development, survival, reproduction and longevity

Flavia da Silva KRECHEMER, Luis Amilton FOERSTER

Eur. J. Entomol. 112 (4): 658-663, 2015 | DOI: 10.14411/eje.2015.103

Tuta absoluta (Meyrick, 1917) is the main pest of tomato crops in South America. Recently, it was also reported in several countries in Europe and the Middle East. Because of its invasive potential and the lack of information on the biology of T. absoluta, the present study aimed to estimate its thermal requirements and evaluate the effect of temperature on its development, survival, reproduction and longevity. The experiments were carried out at constant temperatures of 10, 15, 20, 25 and 30°C. T. absoluta completed its development at all these temperatures. The thermal requirements were estimated by linear regression; the insects required 416.7 degree-days to complete the cycle from egg to adult, and the lower temperature threshold was estimated to be 8.0°C. The upper temperature threshold estimated for the egg-adult cycle was 37.3°C. The pre-oviposition period was longer at 10°C, but the oviposition period was similar at all the temperatures tested. Fecundity was highest at 20 and 25°C, with averages of 134.8 and 149.1 eggs per female, respectively. The highest percentages of fertile eggs were recorded at 15, 20 and 25°C. At 10 and 30°C, only one egg clutch was laid by T. absoluta. No differences were recorded in the longevity of females and males of T. absoluta. The tomato leaf miner can develop over a wide range of temperatures; however, its reproduction and survival were negatively affected at the extreme constant temperatures tested. The temperature variation recorded in natural environments is suitable for this pest to infest tomato crops.

Prey abundance and intraguild predation between Adalia bipunctata (Coleoptera: Coccinellidae) and Macrolophus pygmaeus (Hemiptera: Miridae)

Vincenzo TROTTA, Juliana DURÁN PRIETO, Paolo FANTI, Donatella BATTAGLIA

Eur. J. Entomol. 112 (4): 862-865, 2015 | DOI: 10.14411/eje.2015.080

Macrolophus pygmaeus Rambur (Hemiptera: Miridae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae) are two predatory insects commonly used as biological control agents. In order to determine the incidence with which both species attack and eat each other [Intraguild predation (IGP)], the direction and symmetry of the interaction between A. bipunctata and M. pygmaeus were characterized. In addition, whether the intensity of IGP between these two predators increased when the number of extraguild prey Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) decreased, was also determined. Unidirectional sensu stricto IGP between A. bipunctata and M. pygmaeus was recorded: when IGP occurred, A. bipunctata was always the IG predator that killed and ate M. pygmaeus, the IG prey. However, the intensity of IGP was a function of the abundance of the extraguild prey, A. pisum, since IGP increased when the number of extraguild prey decreased. These results are discussed in terms of theoretical models that predict stability and the outcome of using natural enemies to control pests.

The effects of oviposition site on the development of the wood borer Coraebus florentinus (Coleoptera: Buprestidae)

Ana M. CÁRDENAS, Patricia GALLARDO

Eur. J. Entomol. 110 (1): 135-144, 2013 | DOI: 10.14411/eje.2013.019

Coraebus florentinus (Herbst) is one of the most important wood borer pests of oaks in forest ecosystems in the Mediterranean Region. It is considered to be a heliophilous species as it prefers the sunniest parts of the canopy of isolated trees. The biological significance of this preference is still unknown. Recently, the effect of temperature on the preimaginal development of this insect was established: high temperatures increase its probability of survival and shorten its developmental time. Continuing this line of research, this study was designed to determine whether C. florentinus exhibits selective oviposition behaviour and how variation in temperature due to differences in the position of the branches in which the larvae develop could affect the subsequent development of this species. To determine whether this insect selects the branches in which to lay its eggs, location data (north, south, upper half and lower half of the tops of the trees) for 112 damaged branches were analysed. The results confirm that females of C. florentinus do not lay their eggs at random at the tops of trees but rather choose branches that are exposed to the sun. To determine the effects of larval rearing temperature on the later development stages, an experiment consisting of five treatments was performed. Four of these treatments, each containing 25 infested branches derived from different orientations and positions in a tree (upper half of tree and north facing, upper half and south facing, lower half and north facing and lower half and south facing) were kept in culture chambers maintained at optimal conditions for pupal development (28 ± 2°C and 60-65% relative humidity). The fifth treatment with 25 branches infested collected from the most sun-exposed locations were kept in outdoor conditions. The results indicate that variation in temperature during larval development due to differences in branch location does not significantly affect survival, duration of developmental of pupae, emergence success or sex ratio of the adults.

Species composition and dynamics in abundance of migrant and sedentary butterflies (Lepidoptera) at Gibraltar during the spring period

Keith J. BENSUSAN, Rebecca NESBIT, Charles E. PEREZ, Piotr TRYJANOWSKI, Piotr ZDUNIAK

Eur. J. Entomol. 111 (4): 555-559, 2014 | DOI: 10.14411/eje.2014.057

In order to understand patterns of abundances of migratory Lepidoptera in southernmost Europe and contrast this with those of sedentary species, we studied butterflies surveyed along transects during three spring migration seasons at the Rock of Gibraltar. Overall, 2508 butterflies belonging to 19 species were recorded. Of these, the four most numerous species accounted for almost 88% of all individuals recorded. These were the migratory Clouded Yellow Colias croceus, Red Admiral Vanessa atalanta and Painted Lady Vanessa cardui, and the sedentary Common Blue Polyommatus icarus. There was a significant correlation between abundance of P. icarus and C. croceus. Furthermore, abundances of C. croceus and V. atalanta were correlated. The sometimes very high abundance of migratory butterflies at the study site could suggest that Gibraltar is a stopover site for butterflies migrating between Africa and Europe.

Quantifying predation pressure along an urbanisation gradient in Denmark using artificial caterpillars

Marco FERRANTE, Alessandro LO CACCIATO, Gabor L. LÖVEI

Eur. J. Entomol. 111 (5): 649-654, 2014 | DOI: 10.14411/eje.2014.082

Urbanisation results in a marked modification of habitats and influences several ecological processes, some of which give rise to beneficial ecological services. Natural pest control, the effect of predators on prey is one of such services. We quantified changes in the incidence of predation with increasing levels of urbanisation using artificial caterpillars made of green plasticine. Potential predators can be identified by the "attack marks" they leave on these artificial caterpillars. We conducted this study from May to October 2010 around the city of Sorø (Zealand, Denmark), in forests along an urbanisation gradient (rural-suburban-urban). Artificial caterpillars were placed on the ground in order to obtain an estimate of the incidence of predation at ground level. Half (50%) of the 1398 caterpillars were "attacked" and 28.8% of the bites were those of chewing insects. We attributed the majority of these to carabids, the most common group of ground-active arthropods. Chewing insects exerted the greatest predation pressure in the original forest (52.1%), with lower values recorded in the suburban (10.1%) and urban (16.4%) forest fragments. Ants were responsible for only 4.7% of the attacks in forest, 11.3% in suburban and 16.4% in urban forest fragments. Mammals exerted the highest predation pressure in suburban habitats (22.2% vs. 4.9% in forest, and 8.1% in urban forest fragments).

Evaluation of the diet of a carabid predator using fluorescent marking of prey

Jan OKROUHLIK, Pavel FOLTAN

Eur. J. Entomol. 112 (3): 477-485, 2015 | DOI: 10.14411/eje.2015.054

We present a UV-fluorescent dye-based prey marking technique, using three different dyes, with later detection of the dyes in the guts of predators using a micro-plate fluorescent reader. By using this new method of detecting dyes based on their different excitation and emission characteristics it is possible to simultaneously screen 96 samples for multiple fluorescent-markers in less than 30 minutes. The marking is stable, cheap, non-toxic and had no effect on the choice of the carabid predator Pterostichus melanarius between marked and unmarked fly larvae (Musca domestica). Different fluorescent dyes provide variable detection intervals up to 100% detectability at 96 h post-ingestion by this predator. The simple marking, extraction and detection methods presented could be used in food web research to map individual trophic links and predator preference for different types of prey.

Origins and genetic diversity of the ragweed beetles, Ophraella communa (Coleoptera: Chrysomelidae), that were introduced into Italy and Japan based on an analysis of mitochondrial DNA sequence data

Yudai NISHIDE, Yuya FUKANO, Hayato DOI, Toshiyuki SATOH, Hiroki INOUE, Marco BORIANI

Eur. J. Entomol. 112 (4): 613-618, 2015 | DOI: 10.14411/eje.2015.086

Ophraella communa (Coleoptera: Chrysomelidae) is an oligophagous herbivorous beetle that feeds on Ambrosia artemisiifolia. It is native to North America, but was accidentally introduced into Japan in 1995 and Europe in 2013. We analyzed partial DNA sequences of the mitochondrial cytochrome oxidase II gene for O. communa collected from 29 locations in the United States, Japan and Italy. Overall, the results of our analyses indicate that the introduced Japanese populations have lower genetic variation than the native populations. The sequences for the Italian specimens did not share haplotypes with Japanese specimens. These results indicate that the introduced Japanese populations originated from a single introduction, and that the Italian and Japanese populations have different origins.

Epitrix papa sp. n. (Coleoptera: Chrysomelidae: Galerucinae: Alticini), previously misidentified as Epitrix similaris, is a threat to potato production in Europe

Marina J. ORLOVA-BIENKOWSKAJA

Eur. J. Entomol. 112 (4): 824-830, 2015 | DOI: 10.14411/eje.2015.096

A nonnative pest of potato recently established and causing significant economic damage in Portugal and Spain was initially identified as Epitrix similaris Gentner and included on lists of quarantine pests. The identity of this pest was doubted by some experts, since E. similaris is a rare species previously recorded only from California and does not damage potato in its native range. Our comparison of 20 specimens of this pest from Portugal with paratypes of E. similaris has revealed that it is not E. similaris. The name "Epitrix similaris" should be removed from lists of quarantine pests. The damage to potato tubers caused by the larvae of this pest is similar to that of E. tuberis Gentner, but examination of paratypes of E. tuberis has revealed that the pest is not E. tuberis. This pest differs from all species of Epitrix recorded in the Holarctic and from all known Epitrix pests of potato in the world. Herewith it is described as a new species Epitrix papa sp. n., whose native range is unknown.

Growth and development in a lepidopteran with variable instar number, Pseudocoremia suavis (Geometridae), under standard rearing conditions and when parasitised by Meteorus pulchricornis (Hymenoptera: Braconidae)

Emma I. BARRACLOUGH, Elisabeth P.J. BURGESS, Aliesha M. KEAN, Louise A. MALONE

Eur. J. Entomol. 111 (4): 501-511, 2014 | DOI: 10.14411/eje.2014.062

Though extra instars are often associated with poor conditions and thought to be a compensation for a low growth rate, the reasons why they are necessary, and for variable instar number existing under standard rearing conditions, are not yet clear. In standard rearing conditions, approximately half of Pseudocoremia suavis larvae had five instars (Type I larvae), and half six instars (Type II larvae). Type II larvae took longer to pupate and reached higher pupal weights than Type I larvae. The extra instar was not related to sexual size dimorphism; Type II larvae were not more likely to be females. Females of both Types pupated later than males and had higher pupal weights; this weight gain was achieved wholly via an extended final instar. Relative growth rates (RGR), instar durations and larval weights on weigh days were otherwise the same for both sexes. For most of the larval period, Type II larvae had lower RGR and lower weights than Type I larvae. They also had shorter 3rd, 4th and 5th instars than Type I larvae, and the estimated weights at each moult were significantly lower. The Types are discussed in terms of being, in species with weight thresholds for pupation, not optional "strategies" involving different critical weight ratios for larval moults, but as an inevitable consequence of physiological timing constraints upon reaching the critical weights for larval moults causing large variation in size after the moult. Small larvae may then need an extra instar to reach pupation. When parasitised in the second instar by Meteorus pulchricornis, P. suavis larvae produced parasitoids in either their fourth (4th instar emerging (IE)) or fifth instar (5th IE). The estimated moulting weights at each instar of 4th IE and 5th IE hosts were very similar to those of Type I and Type II unparasitised larvae respectively, which, together with similarity of instar duration patterns, is strongly suggestive of Types being present within parasitised larvae. The proportion of 5th IE hosts in the much slower-growing parasitised treatment was greater than the proportion of Type II larvae in the unparasitised treatment, as might be expected if Type II is associated with lower RGR. The lack of further Types appearing is consistent with extra instars being a compensation for small weight after the moult rather than low RGR per se.

Pollen types collected by Tetragonisca angustula (Hymenoptera: Apidae) in dry vegetation in Northeastern Brazil

Jaílson Santos De NOVAIS, Maria Lúcia ABSY, Francisco De Assis Ribeiro Dos SANTOS

Eur. J. Entomol. 111 (1): 25-34, 2014 | DOI: 10.14411/eje.2014.004

Knowing the floral origin of the pollen collected by native bees in Neotropical ecosystems enables us to understand the dynamics of the interdependent relationships between the insects and the native flora. The objectives of this study were to: (i) investigate the spectrum of plant species from which pollen is collected by Tetragonisca angustula in caatinga (dry vegetation) areas in the semiarid region of Northeastern Brazil; (ii) identify pollen types that could be used as regional geographical markers and (iii) determine the pollen niche breadth and the pattern of use of floral resources by this stingless bee. In total, 23 samples of the pollen stored by T. angustula were collected monthly and subjected to acetolysis. Of the 45 pollen types identified that of Prosopis juliflora (Fabaceae) and Solanum (Solanaceae) were the most frequently represented in the samples and 19 were collected by the bees at both study sites. Species characteristic of caatinga, such as Poincianella pyramidalis (Tulasne) L.P. Queiroz and Senna macranthera (de Candolle ex Colladon) H.S. Irwin & Barneby, were among the pollen identified and they were used as indicators of the geographical origin of the samples. The average values of the pollen niche breadth (H') and equitability (J') indicate that T. angustula is a generalist and homogeneous forager of the floral resources in caatinga.

How does Oedipoda germanica (Orthoptera: Acrididae) cope on the northern edge of its distribution? A demographical study of a completely isolated population

Stanislav RADA, Lucie ©TÌPÁNOVÁ, Jan LOSÍK, Jan ©IPO©, Jaroslav HOLU©A, Tomá¹ KURAS

Eur. J. Entomol. 112 (3): 486-492, 2015 | DOI: 10.14411/eje.2015.062

We studied a population of the Red-winged grasshopper Oedipoda germanica, which is a highly stenotypic and endangered species in Central Europe. The locality studied is completely isolated and at the northern limit of this species distribution (north-west of the Czech Republic). We used capture-mark-recapture in 3 consecutive years (2008-2010). We estimated the total population size using POPAN software to be 136 adults in 2008, 70 in 2009 and 122 in 2010. Estimated daily survival rate (Ф) ranged from 0.950 to 0.987. We constructed linear mixed models to test for apparent survival in relation to temperature data. Temperatures (i.e. mean air temperature and maximum air temperature) were found to have significant effects on survival. The population studied is small, isolated and thus threatened by extinction, as are other O. germanica populations at the northern limit of their distribution. The preservation of indigenous populations in their localities can be achieved by active management, including the removal of shrubs and trees.

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