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A new method for the release of Amblyseius andersoni (Acari: Phytoseiidae) in young apple orchardsÁrpád SZABÓ, Béla PÉNZESEur. J. Entomol. 110 (3): 477-482, 2013 | DOI: 10.14411/eje.2013.063 The use of phytoseiid species in biological plant protection is widespread. However, the techniques used to release them differ. The possible release of Amblyseius andersoni (Chant, 1959) using a new method was tested. High numbers of this mite overwinter in the ground litter in Hungarian orchards. By transferring such ground litter to plots in young orchards, the population density was found to be significantly increased in the release compared to control plots; A. andersoni became the dominant phytoseiid species in the new orchard. Due to the rate at which it spreads, this species was also recorded in the control plots towards the end of the growing season (Aug., Sept.), at which time there was no significant difference in the numbers of this species in the treated and control plots. In the winter following release, A. andersoni was found in the ground litter of the orchard. |
Response of Lymantria dispar (Lepidoptera: Lymantriidae) larvae from differently adapted populations to allelochemical stress: Effects of tannic acidMarija MRDAKOVIĆ, Vesna PERIĆ MATARUGA, Larisa ILIJIN, Milena VLAHOVIĆ, Milena JANKOVIĆ TOMANIĆ, Dejan MIRČIĆ, Jelica LAZAREVIĆEur. J. Entomol. 110 (1): 55-63, 2013 | DOI: 10.14411/eje.2013.007 The effects of tannic acid on mean values and genetic variation in fitness-related traits (mass, relative growth rate) and specific activities of digestive enzymes (total proteases, a-glucosidase and lipase), and genetic variation in their plasticity, were investigated in fifth instar larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae) originating from two populations with different host use histories (oak and locust-tree). The two populations did not differentiate with respect to fitness-related traits, i.e. adverse effects of tannic acid were similar in both populations. However, Robinia larvae, which originated from the locust-tree forest, were characterized by higher total protease and lipase activity and lower a-glucosidase activity than Quercus larvae, which originated from the oak forest. Higher plasticity of lipase and lower plasticity of a-glucosidase in response to tannic acid were also recorded. Quantitative genetic analysis revealed mostly significant expression of genetic variation in the examined traits and trait plasticity, suggesting the potential for evolution of adaptive plastic responses to new environmental conditions and presence of a stressor. The genetic correlations observed between the environments significantly differed from "one", which indicates there are no constraints on the evolution of trait plasticity. |
The plant bug genus Psallus (Heteropera: Miridae) in the Korean Peninsula with descriptions of three new speciesRam Keshari DUWAL, Tomohide YASUNAGA, Sunghoon JUNG, Seunghwan LEEEur. J. Entomol. 109 (4): 603-632, 2012 | DOI: 10.14411/eje.2012.074 There are twenty-six species of the genus Psallus Fieber, 1858 (Phylinae: Phylini) documented in the Korean Peninsula. Three new species are described: Psallus cheongtaensis sp. n., P. ernsti sp. n. and P. suwonanus sp. n., and four species are reported from Korea for the first time: Psallus cinnabarinus Kerzhner, 1979, P. flavescens Kerzhner, 1988, P. loginovae Kerzhner, 1988, and P. roseoguttatus Yasunaga & Vinokurov, 2000. The genitalic structures of females and males are described and figured for most treated species. A key is provided for identifying all the Korean species. |
Multicoloniality in the highly polygynous ant Crematogaster pygmaea (Formicidae: Myrmicinae)Rachid HAMIDI, Gabriel DEBOUT, Ana HEREDIA, Denis FOURNIER, Yves QUINET, Jean-Christophe De BISEAUEur. J. Entomol. 109 (1): 95-102, 2012 | DOI: 10.14411/eje.2012.012 In social insects, the high variability in the number of queens per colony raises fundamental questions about the evolution of altruism. It is hypothesized, for instance, that nestmate recognition should be less efficient in polygynous than in monogynous colonies because the presence of several breeders increases the diversity of genetically determined recognition cues, leading to a less specific colonial signature. Recent studies, however, have shown that the link between the number of queens in a colony and the recognition abilities of its members is more complex than previously suggested. Here, we studied intraspecific aggression, diversity of potential recognition cues and genetic structure of colonies in the highly polygynous ant Crematogaster pygmaea. Our results reveal that workers of this species are clearly aggressive towards non-nestmates in field experiments but not in more artificial bioassays conducted in Petri dishes, underscoring the importance of context-dependent aspects of the assessment of nestmate recognition. Behavioural, genetic and chemical data show that C. pygmaea is a multicolonial species, forming spatially restricted and well-defined entities. Therefore, the postulated negative correlation between recognition ability of workers and queen number in a colony is not supported by the results of this study. |
Effect of the size of the pupae, adult diet, oviposition substrate and adult population density on egg production in Musca domestica (Diptera: Muscidae)Berta PASTOR, Helena ČIČKOVÁ, Milan KOZÁNEK, Anabel MARTÍNEZ-SÁNCHEZ, Peter TAKÁČ, Santos ROJOEur. J. Entomol. 108 (4): 587-596, 2011 | DOI: 10.14411/eje.2011.076 In order to enhance the mass production of the house fly, Musca domestica, five aspects of its oviposition biology were analyzed. Oviposition substrate and the manner of its presentation, the composition of the diet of the adults, size of the pupae and numbers of flies in a cage were identified as critical. Females preferred to lay eggs on a substrate which was presented within a shelter and with increased linear edges against which the flies could oviposit. Different types of oviposition substrate resulted in comparable yields of eggs. The presence of an oviposition attractant (ammonia) in the manure was found to have a potentially positive effect on female fecundity. Egg yield increased when two protein sources (yeast and milk) were included in the adult diet. However, flies fed a mixture of sugar and yeast laid over 50% fewer eggs than those fed the same proportion of sugar and milk. The fecundity of flies decreased with increase in the number of flies per cage, but the highest total number of eggs per cage was obtained when the flies were most crowded (14.2 cm3 per fly). The size of the pupae did not significantly affect egg production. |
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. QUARTAUEur. 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. |
Accumulation and effects of cyanobacterial microcystins and anatoxin-a on benthic larvae of Chironomus spp. (Diptera: Chironomidae)Magdalena TOPOROWSKA, Barbara PAWLIK-SKOWROŃSKA, Renata KALINOWSKAEur. J. Entomol. 111 (1): 83-90, 2014 | DOI: 10.14411/eje.2014.010 Larvae of Chironomidae are distributed world-wide and are very abundant in eutrophic water bodies affected by cyanobacterial blooms. However, there is little information on the effect of cyanobacteria and their metabolites on these aquatic organisms. Our studies revealed that benthic species of Chironomus inhabiting a hypertrophic lake where blooms of microcystin (MC) and/or anatoxin-a (ANTX)-producing filamentous Planktothrix agardhii, Dolichospermum spp. and Cuspidothrix issatschenkoi occur, fed on these cyanobacteria and accumulated cyanotoxins. Up to 3.2 µg MCs g-1 F.W. and up to 185 µg ANTX g-1 F.W. were detected. Of the four MC variants detected in the cyanobacterial biomass [Asp3, Dhb7]MC-RR and MC-LR prevailed, whereas in the larvae it was [Asp3, Dhb7]MC-RR and MC-LA. The effect of pure MC-LR and ANTX as well as crude extracts of MC-producing P. agardhii and ANTX-producing D. lemmermannii on lake and riverine larvae of Chironomus spp. was also compared. The assays revealed that pure cyanotoxins (concentrations: 0.83-3.32 mg L-1) were generally less toxic to riverine larvae than cyanobacterial extracts containing approximately 10-times less toxins. The survival of both the lake and riverine Chironomus larvae did not decrease when exposed to environmentally relevant concentrations of cyanotoxins (< 0.20 mg L-1). The larvae were also highly resistant to higher amounts (up to 0.35 mg ANTX L-1 and 0.42 mg MCs L-1) of extracellular toxins. In the natural environment, Chironomus larvae exposed to toxins contained in cyanobacterial prey, dissolved in water and/or bound to bottom sediments may be very important vectors of cyanotoxins to higher levels in aquatic food chains. To the best of our knowledge, this is the first report on the accumulation of ANTX and effects of cyanotoxins on Chironomus larvae. |
A question of adaptability: Climate and habitat change lower trait diversity in butterfly communities in south-western GermanyKatharina J. FILZ, Martin WIEMERS, Anne HERRIG, Matthias WEITZEL, Thomas SCHMITTEur. J. Entomol. 110 (4): 633-642, 2013 Invertebrate diversity has rapidly declined throughout Europe during the last century. Various reasons for this decrease have been proposed including human induced factors like climate change. Temperature changes alter distributions and occurrences of butterflies by determining habitat conditions at different scales. We evaluated changes in the composition of butterfly communities recorded at nine areas of fallow ground in south-western Germany in 1973, 1986, 2010 and 2012 using Pollard's transect technique. To demonstrate the importance of climatic changes in affecting butterfly communities, we calculated the community temperature index (CTI) for each butterfly community in each year. Although they increased slightly, the CTI-values did not match the temperature trends recorded in the study region. However, the reduction in the standard deviations of the CTIs over time is reflected in the marked loss of cold- and warm-adapted species due to their inability to cope with temperature and land-use induced habitat changes. Results of our butterfly surveys indicate a marked decline in species richness and striking changes in the composition of the butterfly communities studied. This trend was most pronounced for habitat specialists, thus mirroring a depletion in trait diversity. Our results indicate that, in the course of large-scale anthropogenic changes, habitat degradation at smaller scales will continuously lead to the replacement of habitat specialists by ubiquitous species. |
Shifted migration of the rape stem weevil Ceutorhynchus napi (Coleoptera: Curculionidae) linked to climate changeMichael EICKERMANN, Marco BEYER, Klaus GOERGEN, Lucien HOFFMANN, Jürgen JUNKEur. J. Entomol. 111 (2): 243-250, 2014 | DOI: 10.14411/eje.2014.018 A multi-model ensemble of 15 climate change projections from regional climate models was used to assess the impact of changes in air temperature and precipitation on the phenology of pest species in agriculture. This allowed the bandwidths of expected changes in both meteorological variables to be calculated, forming the basis for assessing and clearly communicating the uncertainties related to the model results. More specifically, we investigated the potential impact of regional climate change effects on the crop invasion of the rape stem weevil, Ceutorhynchus napi Gyllenhal (Coleoptera: Curculionidae), in Central Europe (Luxembourg). Multisite and perennial data from field observations were used to choose a biological model from the literature, based on daily maximum air temperature and daily totals of precipitation to describe the migration of C. napi. Based on this statistical relation, we were able to reproduce the observed crop invasion with a mean root mean squared error (RMSE) of 10 days. Daily values of projected maximum air temperatures and daily totals of precipitation of the multi-model ensemble were used as input data for the threshold-based biological model that projects the immigration of this pest species into oilseed rape crops (Brassica napus L.). We examined three thirty-year timespans, the near (2021 to 2050) and the far future (2069 to 2098) and compared them to a reference timespan (1961 to 1990). The projections showed a significant shift of crop invasion to an earlier onset for the near (14 days) and far future (21 days) compared to the reference period. In addition, the timespan in which the potential crop invasion will take place increased from 53 days in the reference timespan to 73 days in the near and 65 days in the far future based on the ensemble median values. It could be expected that a shifting of the immigration period will increase the risk of missing the appropriate time frame for an insecticide application. A depletion of stored nutrient resources, leading to starvation after diapause, can be eliminated for C. napi under climate change effects, as this species hibernates motionless as an adult in earth cocoons until emergence in early springtime driven by temperature. |
Age-related changes in the frequency of harassment-avoidance behaviourof virgin females of the small copper butterfly, Lycaena phlaeas (Lepidoptera: Lycaenidae)Jun-Ya IDEEur. J. Entomol. 111 (3): 417-420, 2014 | DOI: 10.14411/eje.2014.037 Mated females of the small copper butterfly Lycaena phlaeas avoid harassment by males by closing their wings and concealing themselves when in the proximity of a con-specific butterfly. This wing-closing behaviour is less frequently exhibited by virgin females that are two days old or older (i.e., potentially receptive) than by mated females. During the first 2 days after emergence, females of L. phlaeas are sexually immature and unreceptive. To determine whether recently emerged virgin females try to avoid male harassment, age-related changes in the frequency of harassment-avoidance behaviour of virgin females were investigated. On the day of emergence, a high percentage of virgin females exhibited wing-closing behaviour. Over the following 2 days, however, the frequency of this behaviour declined sharply and then reached a constant low level. This observation supports the idea that the harassment-avoidance behaviour exhibited by virgin females of L. phlaeas depends on their receptivity. |
Demography of adults of the Marsh fritillary butterfly, Euphydryas aurinia (Lepidoptera: Nymphalidae) in the Czech Republic: Patterns across sites and seasonsKamil ZIMMERMANN, Pavla BLAZKOVA, Oldrich CIZEK, Zdenek FRIC, Vladimir HULA, Pavel KEPKA, David NOVOTNY, Irena SLAMOVA, Martin KONVICKAEur. 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. |
Muga silkworm, Antheraea assamensis (Lepidoptera: Saturniidae) - an overview of distribution, biology and breedingAmalendu TIKADER, Kunjupillai VIJAYAN, Beera SARATCHANDRAEur. J. Entomol. 110 (2): 293-300, 2013 | DOI: 10.14411/eje.2013.096 Muga silkworm (Antheraea assamensis Helfer) is endemic to Assam and adjoining areas in North-Eastern India, and naturally produces golden silk. From time immemorial, many ethnic and tribal groups have produced muga silk. Muga silkworms are mostly wild unlike the mulberry silkworm, which is completely domesticated. The muga silkworm is a single species with little genetic variation among populations, survives harsh climatic conditions and is subject to various diseases, pests and predators. Due to the high incidence of disease and natural enemies, and variations in climatic conditions, the production of muga silk has recently declined dramatically. In order to improve the productivity of this silkworm it is important to have a better knowledge of both its host plants and biology. Lack of knowledge of its genetics and host plants is a major bottleneck. This paper reviews various aspects of muga silkworm culture, including the availability of different populations, and methods used to select for improvement in survival, cocoon yield, disease resistance, conservation and egg production. |
Patterns of hind-wing degeneration in Japanese riffle beetles (Coleoptera: Elmidae)Masakazu HAYASHI, Simon D. SONG, Teiji SOTAEur. J. Entomol. 110 (4): 689-697, 2013 We conducted a molecular phylogenetic analysis based on mitochondrial cytochrome oxidase subunit I and nuclear 28S rRNA gene sequences of species of Japanese elmids (23 species from 12 genera) and examined the hind-wings of 24 species in order to determine the incidence of hind-wing degeneration among species and the presence of dimorphic species with respect to hind-wing degeneration. Based on the molecular phylogenetic analysis, we determined that the previously separated winged and wingless species, Stenelmis vulgaris and S. miyamotoi, and Leptelmis gracilis and L. parallela, are two forms of the same species. Of the 24 species whose hind wings were studied, we found apterous (3 species of Zaitzeviaria), brachypterous (2 species of each of Optioservus and Paramacronychus) and dimorphic species (2 species as above) in separate clades of the phylogeny. These were the smallest or medium-sized species. Dimorphic species occurred in mid- to downstream areas and used reeds and wood as substrates. The percentage of species with hind-wing degeneration (wingless or dimorphic) was high among the species (29%) studied compared to the perceived percentage for temperate beetles (<10%). Thus, we found that the degeneration of hind wings has occurred repeatedly in these elmid species. However, we identified only ambiguous habitat and life history correlates of hind-wing degeneration, and the adaptive significance of hind-wing degeneration in these species of elmids remains unclear. |
Effect of conventional and non-inversion tillage systems on the abundance and some life history traits of carabid beetles (Coleoptera: Carabidae) in winter triticale fieldsAgnieszka KOSEWSKA, Tomasz SKALSKI, Mariusz NIETUPSKIEur. J. Entomol. 111 (5): 669-676, 2014 | DOI: 10.14411/eje.2014.078 Soil cultivation is among the principal factors that determine the structure and properties of soil and also affects the species composition and abundance of soil dwelling arthropods. Carabid beetles are a particularly valuable group of arthropods, the species of which are strongly associated with particular soil environments. This paper discusses the effect of soil tillage on carabid beetle assemblages. The study was carried out near Olsztyn, in northeastern Poland. Six wheat fields, each cultivated using either, conventional or non-inversion, soil tillage, were chosen. Carabid beetles were caught in Barber s traps from early April to the end of October 2011. In total, 7,486 specimens belonging to 55 species of the family Carabidae were captured. The most numerous were Poecilus cupreus, Pterostichus melanarius, Harpalus rufipes, Anchomenus dorsalis and Carabus granulatus. Differences in the abundance of ground beetles and some life history traits were associated with the two soil tillage systems. In particular, ploughing reduced carabid abundance and resulted in the increased activity of medium-sized zoophages and spring breeders. |
Are macrophyte-dwelling Chironomidae (Diptera) largely opportunistic in selecting plant species?Mónika TÓTH, Arnold MÓRA, Béla KISS, György DÉVAI, András SPECZIÁREur. J. Entomol. 109 (2): 247-260, 2012 | DOI: 10.14411/eje.2012.033 In this study we evaluate how variations in taxonomic composition and physical structure of macrophyte stands affect plant-dwelling chironomid assemblages in highly variable macrophyte assemblages in two densely vegetated backwaters. By using multivariate explanatory techniques we found that similar vegetation composition did not unequivocally relate to similar chironomid assemblages, moreover the diversity of macrophyte stands did not correlate with the taxonomic diversity of chironomid assemblages in the backwaters investigated. Taxonomic composition and structural characteristics of the vegetation had little influence on the taxonomic or functional (i.e. feeding groups) composition of chironomid assemblages inhabiting them. Similarly, there are only weak relationships between the distribution of certain chironomid species or functional feeding groups and the environmental variables investigated. In general, the structure of the vegetation was more closely associated with the distribution of dominant chironomid taxa than compositional variables (i.e. density of specific macrophyte taxa). In summary, the structure of aquatic vegetation (i.e. position, size of a stand of vegetation, total plant density) and characteristics of the environment where it develops may be more important in shaping plant-dwelling chironomid assemblages than the taxonomic composition of the vegetation. |
A contribution to the karyosystematics of the planthopper families Dictyopharidae and Fulgoridae (Hemiptera: Auchenorrhyncha)Valentina G. KUZNETSOVA, Anna MARYAŃSKA-NADACHOWSKA, Alexander F. EMELJANOVEur. J. Entomol. 106 (2): 159-170, 2009 | DOI: 10.14411/eje.2009.019 The chromosome complements of thirteen species of the planthopper family Dictyopharidae are described and illustrated. For each species, the structure of testes and, on occasion, ovaries is additionally outlined in terms of the number of seminal follicles and ovarioles. The data presented cover the tribes Nersiini, Scoloptini and Dictyopharini of the subfamily Dictyopharinae and the tribes Ranissini, Almanini, and Orgeriini of the Orgeriinae. The data on the tribes Nersiini and Orgeriini are provided for the first time. Males of Hyalodictyon taurinum and Trimedia cf. viridata (Nersiini) have 2n = 26 + X; Scolops viridis, S. sulcipes, and S. abnormis (Scoloptini) 2n = 36 + X; Callodictya krueperi (Dictyopharini) 2n = 26 + X; Ranissus edirneus and Schizorgerius scytha (Ranissini) 2n = 26 + X. Males of Almana longipes and Bursinia cf. genei (Almanini) have 2n = 26 + X and 2n = 24 + XY, respectively. The latter chromosome complement was not recorded previously for the tribe Almanini. Males of Orgerius ventosus and Deserta cf. bipunctata (Orgeriini) have 2n = 26 + X. The testes of males of A. longipes and B. cf. genei each have 4 seminal follicles, which is characteristic of the tribe Almanini. Males of all other species have 6 follicles per testis. When the ovaries of a species were also studied, the number of ovarioles was coincident with that of seminal follicles. For comparison, Capocles podlipaevi (2n = 24 + X and 6 follicles per testis in males) from the Fulgoridae, the sister family to Dictyopharidae, was also studied. We supplemented all the data obtained with our earlier observations on Dictyopharidae. The chromosomal complement of 2n = 28 + X or that of 2n = 26 + X and 6 follicles per testis are suggested to be the ancestral condition among Dictyopharidae, from which taxa with various chromosome numbers and testes each with 4 follicles have differentiated. |
Distribution modelling as an approach to the conservation of a threatened alpine endemic butterfly (Lepidoptera: Satyridae)Maarten DE GROOT, Franc REBEU©EK, Vesna GROBELNIK, Marijan GOVEDIČ, Ali ©ALAMUN, Rudi VEROVNIKEur. J. Entomol. 106 (1): 77-84, 2009 | DOI: 10.14411/eje.2009.012 Mountain butterfly species are often restricted in their distribution and under threat from habitat destruction and climate change. Due to the inaccessibility of their habitats the distributions of many such species are unknown. We have investigated whether information on the habitat requirements of the Alpine endemic species Erebia calcaria could be used for modelling its potential distribution. We surveyed part of its range using transects and recorded habitat and environmental parameters. The most important parameters determining the presence of the species were average height of the vegetation, maximum height of the vegetation, percentage area of bare ground, number of food plants and slope. Furthermore, the abundance of E. calcaria is strongly affected by site exposure and grazing intensity. Using these results we modelled the potential distribution of the species in its known historical range in Slovenia. In the region covered by the model 70% of the records of E. calcaria were within the predicted distribution. It is reasonable to propose that such a high detection rate justifies the use of distribution models for predicting a species range and providing important additional information for their conservation. In the case of E. calcaria, we have shown that endemic mountain butterflies can be strongly threatened by fragmentation of their habitat, overgrazing and succession, which could be further amplified by changes in climate. |
Correlated traits for dispersal pattern: Terrestrial movement of the water cricket Velia caprai (Heteroptera: Gerromorpha: Veliidae)Tomáą DITRICH, Miroslav PAPÁČEKEur. J. Entomol. 106 (4): 551-555, 2009 | DOI: 10.14411/eje.2009.069 Macropterous individuals of wing polymorphic semiaquatic bugs (Heteroptera: Gerromorpha) usually occur at a high frequency if there is a need to leave an unfavorable habitat or in a generation migrating to/from an overwintering site. Velia caprai (Veliidae) is usually found in unpredictable habitats, but the macropterous morph is rare. Laboratory, mesocosm and field experiments were used to test the hypothesis that individuals of this species migrate by walking rather than by flight. Laboratory experiments that focused on the development of macropterous morph under conditions that usually stimulate the development of this morph in water striders were unsuccessful. A high temperature shortened the duration of nymphal development, but no winged specimens of Velia caprai developed in the laboratory when reared under either high or low temperatures, long or short photoperiods or on the surface of water or wet filter paper. Mesocosm experiments with apterous adults revealed they are able to walk on land. Both the males and females dispersed by walking in semi-natural conditions. Long-term field experiments using mark and recapture confirmed that this species can disperse by walking. Apterous individuals can compensate for downstream drift by upstream terrestrial migration and colonize newly established pools and ditches even several tens of meters from source sites. The development of a macropterous morph in response to environmental factors is replaced by terrestrial dispersal in V. caprai. |
Endogenous 20-hydroxyecdysone levels in the haemolymph of non-diapause-destined and diapause-destined generations of tasar silkworm, Antheraea mylitta (Lepidoptera: Saturniidae) and associated developmental changesDinesh KUMAR, Bhattiprolu SUBRAHMANYAM, Shashi K. SHARAN, Pradeep K. MISHRA, Bishwa M.K. SINGH, Nagabathula SURYANARAYANAEur. J. Entomol. 105 (4): 591-598, 2008 A complete profile of the 20-hydroxyecdysone (20-HE) titer, development and endocrine events from 1st instar to pupation of the larvae of non-diapause-destined (NDD) and diapause-destined (DD) tasar silkworm, Antheraea mylitta Drury (Lepidoptera: Saturniidae) was studied. Diapause is induced by short days of 11 hr photophase coupled with <= 24°C prevailing in September-November. Diapausing pupae produce adults in July (>= 12h light, >= 26°C) and one generation is completed by August. The growth rate during the course of development of larval instars decreases and instar durations are inversely related to the body weight at the time of initiation of a larval instar. A growth compensation mechanism operates during the development of the larval instars. The growth rate was higher in early instars (1st to 4th) in both generations. The DD larvae complete the final instar in 16 days followed by a spinning stage of 13 days. The NDD larvae complete the final larval instar in 9 days followed by spinning stage of 6 days and spend 14 days in the pupal stage. The signal to release the prothoracicotropic hormone (PTTH) is related to critical body weight of larvae. From 1st to 4th instar, pre-ecdysial peaks of 20-HE were recorded in both NDD and DD generations. The programme for undergoing diapause was initiated during 3rd instar and induced by a sudden decrease in the level of 20-HE in the DD generation. Two peaks of 20-HE are required for the larval-pupal transformation, first at the wandering stage and the second at cuticle formation. |
Dispersal of Aphytis melinus (Hymenoptera: Aphelinidae) after augmentative releases in citrus orchardsLucia ZAPPALÀ, Orlando CAMPOLO, Saverio Bruno GRANDE, Francesco SARACENO, Antonio BIONDI, Gaetano SISCARO, Vincenzo PALMERIEur. J. Entomol. 109 (4): 561-568, 2012 | DOI: 10.14411/eje.2012.070 The efficacy of natural enemies in controlling pests under field conditions is largely correlated with their capacity to spread within infested crops. In this study the spatial dispersal of the California red scale parasitoid Aphytis melinus DeBach (Hymenoptera: Aphelinidae) was evaluated in the field after augmentative releases. The experiment was conducted in 2007 in six 1-ha plots in a Sicilian citrus orchard under integrated pest management. A total of 180,000 A. melinus adults was released in each of three plots and the other plots were left as untreated control. The flight range of the parasitoid was evaluated, for 35 days after the release, on 16 trees per each plot, located at 20 and 40 m from the central release point using yellow sticky traps activated with Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae) sexual pheromone and by monitoring the percentage parasitism of the scale on fruits and twigs. The effects of the distance from the release point and density of susceptible stages of host on parasitoid dispersal were evaluated. The number of wasps captured during the whole trial was greater in the traps located 20 m from the release point than in those at 40 m and in the control plots. Aphytis melinus dispersed over distances less than 40 m based on both the lower percentage parasitism and numbers captured recorded at distances of 40 m. The results are discussed in the context of the biological control of California red scale in citrus orchards by means of wasp releases. In particular, the release points should be no more than 40 m apart for a quick and homogeneous colonization of the area treated. |
Increasing patch area, proximity of human settlement and larval food plants positively affect the occurrence and local population size of the habitat specialist butterfly Polyommatus coridon (Lepidoptera: Lycaenidae) in fragmented calcareous grasslandsZuzanna M. ROSIN, Piotr SKÓRKA, Magdalena LENDA, Dawid MORON, Tim H. SPARKS, Piotr TRYJANOWSKIEur. J. Entomol. 108 (1): 99-106, 2011 | DOI: 10.14411/eje.2011.013 Which factors influence the occurrence, population size and density of species in fragmented habitat patches are key questions in population and conservation ecology. Metapopulation theory predicts that larger and less isolated habitat patches should positively influence species occurrence and population size. However, recent studies have shown that habitat quality, human activity and permeability of the landscape surrounding habitat patches may be also important. In this paper we test the relative effects of habitat patch characteristics, human settlement and landscape permeability on the occurrence, local population size and density of the Chalk-hill Blue Polyommatus coridon a charismatic butterfly inhabiting calcareous grasslands in a fragmented landscape in southern Poland. Patch occupancy rate (corrected for the butterfly detection probability) was 0.45. Habitat patch area, proximity of human settlement and cover of larval food plants positively affected occurrence of the Chalk-hill Blue. Local population size of the Chalk-hill Blue was positively affected by patch area and proximity of human settlement, and negatively by patch isolation. Local density was higher in patches located close to human settlement. Our study is one of the few showing a positive effect of human settlement on a grassland specialist butterfly although the mechanism hidden behind this phenomenon is unknown and requires further examination. In order to maintain local populations of the Chalk-hill Blue in southern Poland, conservation action should be focused on large, closely connected calcareous grasslands. Moreover, extensive management of this habitat should be maintained by local inhabitants who are better placed to undertake such work. |
Effect of population density on the development of Mesovelia furcata (Mesoveliidae), Microvelia reticulata and Velia caprai (Veliidae) (Heteroptera: Gerromorpha)Tomáą DITRICH, Miroslav PAPÁČEKEur. J. Entomol. 107 (4): 579-587, 2010 | DOI: 10.14411/eje.2010.067 Population density during nymphal development affects body size, developmental rate and wing polymorphism in semiaquatic bugs. Nymphs from crowded habitats grow faster and thus gain an advantage in the later stadia. Rapid development results in smaller body size in several gerrids. Macropterous adults develop more frequently at high population densities in most species, which enables the bugs to leave crowded habitats. Three European widespread species Mesovelia furcata Mulsant & Rey, 1852 (Mesoveliidae), Microvelia reticulata Burmeister, 1835 and Velia caprai Tamanini, 1947 (Veliidae) were reared individually and simultaneously either at a low or high population density. Duration of postembryonic development, wing morph, body size and length of distal oocyte in females were recorded. High population density accelerates development in Mesovelia furcata and Microvelia reticulata. However, there was no trade-off between developmental rate and body size. Accelerated development without a decrease in body size was probably because maturation was delayed. Individually reared nymphs developed faster than nymphs from communal cohorts. No long-winged Microvelia reticulata specimen developed in any treatment. However, more macropterous individuals developed in high-density treatments in Mesovelia furcata (significant) and Velia caprai (not significant). All the nymphs of the species that were reared individually developed into apterous adults. The results suggest that population density strongly influences the life history of semiaquatic bugs. However, the only commonly shared response seems to be an increase in developmental rate when reared at high population densities. Other traits such as wing dimorphism, body size and rate of oogenesis differ at the species level. |
Present conservation status of red wood ants in north-western Belgium: Worse than previously, but not a lost causeWouter DEKONINCK, Frederik HENDRICKX, Patrick GROOTAERT, Jean-Pierre MAELFAITEur. J. Entomol. 107 (2): 209-218, 2010 | DOI: 10.14411/eje.2010.028 The number of colonies of red wood ants (Formica rufa group) in the north western part of Belgium has declined by more than half over the past 20 years. In the study area of 20 × 50 km there are currently only 36 colonies of two species of red wood ants (Formica rufa and F. polyctena). Both species form both monodomous and polydomous colonies. Monodomous F. rufa colonies occur in large areas of open woodland dominated by Pinus sylvestris. The other three types of red wood ant (F. rufa polydomous, F. polyctena mono- and polydomous) occur in clearings or along the margins of small areas of deciduous or mixed woodland. The extinction of red wood ants cannot be attributed to a loss of their main habitat. Their decline in abundance, however, appears to be due to the deterioration in their habitat caused by several factors. Shading by overgrowing shrubs and the closure of the tree canopy, nearby intensive agriculture, urbanisation and use of the forest for recreation are the more important factors threatening and ultimately leading to the extinction of colonies. At poor quality sites there are no or very few nests of Serviformica ants, which initially serve as host ants and are necessary for recolonization by red wood ants. Thus, it is unlikely that these sites will be recolonized. To conserve red wood ants and maintain populations there is an urgent need to undertake certain measures, especially in areas outside nature reserves. For this there is a need to create clearings in the woodland, reduce shading due to overgrowing shrubs and closure of the tree canopy, and mitigate the effects of intensive agriculture, urbanisation and recreation. It is important that the effects of these measures should be monitored. |
Cytogenetic characterization of Diachasmimorpha longicaudata (Hymenoptera: Braconidae), a parasitoid wasp used as a biological control agentLeonela CARABAJAL PALADINO, Alba PAPESCHI, Silvia LANZAVECCHIA, Jorge CLADERA, María José BRESSAEur. J. Entomol. 110 (3): 401-409, 2013 | DOI: 10.14411/eje.2013.054 Diachasmimorpha longicaudata (Hymenoptera: Braconidae) is a parasitoid wasp widely used in the biological control of fruit flies. In this paper, we present a detailed analysis of the karyotype of this species based on the results of classical and molecular cytogenetic techniques. The cytogenetic analysis confirmed the male and female chromosome numbers previously reported (n = 20, 2n = 40). The entire short arm of most chromosomes is made up of a large constitutive heterochromatic segment. The high heterochromatin content differentiates D. longicaudata from other braconid species. Fluorescence in situ hybridization (FISH) using autologous 18S rDNA probes revealed six clusters of rDNA, i.e. six nucleolar organizer regions (NORs), in the heterochromatic short arms of different chromosomes in the haploid male karyotype. This number is exceptionally high for Hymenoptera, which usually have two NORs in the diploid complement. It is noteworthy that these rDNA-FISH experiments represent the first use of this technique on a braconid species using autologous probes. Since Ag-NOR-bands were coincident with C-positive bands on metaphase chromosomes, it was not possible to identify active nucleoli. The physical characteristics of the D. longicaudata karyotype, especially the content and distribution of heterochromatin and the number and location of rDNA clusters, contribute to a better understanding of the structure and organization of braconid chromosomes and provide a basis for genomic and evolutionary studies. |
Pollination of Sedirea japonica (Orchidaceae) by Bombus diversus diversus (Hymenoptera: Apidae)Kenji SUETSUGU, Koji TANAKAEur. J. Entomol. 110 (3): 545-548, 2013 | DOI: 10.14411/eje.2013.074 There are no records of the pollinators of many orchids even though the Orchidaceae are often cited as the example of an intimate relationship between plants and their pollinators. We recorded the insects visiting the flowers of Sedirea japonica that might be pollinators of this species by using digital cameras to take photographs automatically of the flowers. Based on our evidence of pollinia being attached or removed from flowers, we conclude that Sedirea japonica can be pollinated by Bombus diversus diversus. |
Temperature dependent functional response of Diaeretiella rapae (Hymenoptera: Aphidiidae) to the cabbage aphid, Brevicoryne brassicae (Hemiptera: Aphididae)Hamid R.S. MOAYERI, Hossein MADADI, Hossein POURASKARI, Annie ENKEGAARDEur. J. Entomol. 110 (1): 109-113, 2013 | DOI: 10.14411/eje.2013.015 Diaeretiella rapae MacIntosh (Hymenoptera: Aphidiidae) is one of the most common and successful parasitoids of the cabbage aphid. The functional response of D. rapae towards cabbage aphids was examined in laboratory studies at three constant temperatures, 17°C, 25°C and 30°C. D. rapae exhibited a type II functional response at all three temperatures. The search rates were uninfluenced by temperature whereas handling times differed significantly between 17°C and 25°C, and between 17°C and 30°C, but not between 25°C and 30°C. This study is a first-step in the evaluation of the effectiveness of D. rapae as a biocontrol agent of Brevicoryne brassicae at different temperatures. |
First record of the harlequin ladybird, Harmonia axyridis (Coleoptera: Coccinellidae) in the CaucasusNatalia A. BELYAKOVA, Sergey Ya. REZNIKEur. J. Entomol. 110 (4): 699-702, 2013 This is the first record of the harlequin ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) occurring in the Caucasus (Sochi region of Krasnodar territory, Russia). All the adults collected in the field there and reared from collected eggs, larvae and pupae, and their progeny were H. axyridis f. succinea, which is the most common morph in natural populations in South-Eastern Asia and the Russian Far East as well as in invasive populations in the Americas and Europe. In contrast in Western Siberia f. axyridis predominates and this indicates that an occasional introduction from the closest native range in Siberia cannot be considered as the source of the Caucasian population. It is known that populations of H. axyridis can also differ in their photoperiodic responses. The results of earlier experiments on H. axyridis, which originated from the Russian Far East, indicate that the threshold day lengths for the acceleration of preimaginal development and deceleration of reproductive maturation were 13-14 h, while for the invasive populations of this species in Europe these two thresholds are approximately 12 h. In the population studied, the thresholds for both of these photoperiodic responses were also approximately 12 h. Thus, it is concluded that the population of H. axyridis studied is a further eastward continuation of the invasion of this species in Europe. |
Population structures of three Calliptamus spp. (Orthoptera: Acrididae) across the Western Mediterranean BasinElodie BLANCHET, Michel LECOQ, Gregory A. SWORD, Christine PAGES, Laurence BLONDIN, Claire BILLOT, Ronan RIVALLAN, Antoine FOUCART, Jean-Michel VASSAL, Ange-Marie RISTERUCCI, Marie-Pierre CHAPUISEur. J. Entomol. 109 (3): 445-455, 2012 We conducted a comparative population genetic analysis of levels of genetic variation and its geographical structuring in three closely related species of grasshopper that co-occur in the Mediterranean Basin: Calliptamus italicus, C. barbarus and C. wattenwylianus. In the western part of their distributions 5 populations of C. italicus, 13 of C. barbarus and 10 of C. wattenwylianus were sampled. Bootstrap re-sampling of populations and microsatellite loci within each species indicated a lower level of genetic diversity and higher level of genetic differentiation in C. barbarus, which is less of an outbreak pest species than either of the other Calliptamus species studied. This may be due to lower effective sizes of non-outbreak populations and/or lower gene flow among them. |
Scorpion reproductive strategies, allocation and potential; a partial reviewMichael R. WARBURGEur. 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. |
Comparative analysis of maternal and grand-maternal photoperiodic responses of Trichogramma species (Hymenoptera: Trichogrammatidae)Natalia D. VOINOVICH, Nina P. VAGHINA, Sergey Ya. REZNIKEur. J. Entomol. 110 (3): 451-460, 2013 | DOI: 10.14411/eje.2013.060 Maternal and grand-maternal photoperiodic responses of Trichogramma buesi, T. embryophagum, T. evanescens, T. piceum, T. principium, and T. telengai were investigated in laboratory conditions. During the experiment, grand-maternal and maternal generations developed at 20°C and one of the 4 photoperiodic regimes: L : D = 12 : 12, 14 : 10, 16 : 8, and 18 : 6 (in total, 16 combinations) while the progeny developed at L : D = 12 : 12 and one of the 3 thermal regimes: 13, 14, and 15°C. The proportion of diapausing individuals in the progeny of all the studied species was significantly dependent on the direct influence of temperature and on the maternal photoperiodic response. The influence of the photoperiodic conditions during development of the grand-maternal generation was statistically significant in 5 of the 6 studied species, being relatively weak in T. embryophagum and T. telengai, whose geographical ranges extend up to north-western regions of Europe (possibly, these wasps enter diapause so early that the grand-mothers of the diapausing generation develop under long day conditions). Comparative analysis showed that the thresholds of the maternal and grand-maternal photoperiodic responses coincided or almost coincided. The grand-maternal effect was stronger in the progeny of maternal females which developed under short day conditions than in those that developed under long day conditions. This pattern of interaction probably synchronizes the life cycle with seasonal changes because diapause is induced under decreasing day length and thus mothers of diapausing individuals develop at shorter daylength than do grand-mothers. We conclude that the grand-maternal and the maternal effects on Trichogramma progeny diapause are based on one and the same photoperiodic response. In nature, the grand-maternal effect increases the proportion of diapausing individuals in the progeny of females which have developed under short day conditions during two generations, thus achieving a "cumulative" photoperiodic effect. |



