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Community structure and reproductive biology of bark beetles (Coleoptera: Scolytinae) associated with Macaronesian Euphorbia shrubsBjarte H. JORDALEur. J. Entomol. 103 (1): 71-80, 2006 | DOI: 10.14411/eje.2006.012 Dead wood of arborescent Euphorbia plants in the Macaronesian islands and Morocco has a diverse fauna of wood-boring beetles. Thirty-eight species were found in four species groups of Euphorbia, including 29 species of scolytine bark beetles, six species of cossonine weevils, two species of Laemophloeidae and one of Monotomidae. All scolytines (but not cossonines and cucujoids) have narrow host preferences, using only one host group for feeding and reproduction. The number of islands on which each species was found was also limited, resulting in geographically distinct guilds for each Euphorbia host. The majority of species (26) were found on the E. lamarckii species complex, followed by E. balsamifera (13) and the succulents E. canariense (12) and E. echinus (3), while only two species were found on the rare montane species, E. longifolia, in Madeira. Up to six or seven species could be found in a single branch of E. lamarckii and E. canariense, respectively, but more than half of the plants had fewer than three species. Putative niche partitioning was indicated by the alternative utilization of different tissues in E. balsamifera and different moisture preferences in the succulent E. canariense. Several unusual features of bark beetle reproductive biology were also observed, including infrequent communal nesting and very small broods. Taken together with the phylogenetic, geographical and biological data now available for most species associated with dead Euphorbia, several of the beetle guilds should provide promising model systems for studying of species interactions and community structure. |
Oldest records of Bombyliidae: Phthiriinae and Mythicomyiidae: Glabellulinae from the Lowermost Eocene amber of France (Diptera: Bombylioidea)André NELEur. J. Entomol. 103 (1): 109-114, 2006 | DOI: 10.14411/eje.2006.016
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The identity of Pseudopsila, description of a new subgenus of Psila, and redefinition of Psila sensu lato (Diptera: Psilidae)Matthias BUCK, Stephen A. MARSHALLEur. J. Entomol. 103 (1): 183-192, 2006 | DOI: 10.14411/eje.2006.021 The type species of Pseudopsila Johnson, P. fallax (Loew), and two related species are found to belong in Psila s. str., and Pseudopsila is thus synonymized with Psila Meigen. The remaining species formerly included in Pseudopsila form a monophyletic group here described as Xenopsila Buck subgen. n. [i.e., Psila (Xenopsila) collaris Loew comb. n., P. (X.) bivittata Loew comb. n., P. (X.) lateralis Loew comb. n., P. (X.) arbustorum Shatalkin comb. n., P. (X.) nemoralis Shatalkin comb. n., P. (X.) tetrachaeta (Shatalkin) comb. n., P. (X.) maculipennis (Frey) comb. n., P. (X.) nigricollis (Frey) comb. n., P. (X.) nigrohumera (Wang & Yang) comb. n.]. A key to the Nearctic species of Xenopsila and the Psila fallax-group is provided. The placement of Xenopsila in Psila s. l. is confirmed by newly recognised synapomorphies of the egg stage. The somewhat questionable monophyly of Psila s. l. is confirmed based on these new synapomorphies, thereby slightly expanding its taxonomic limits to also include Asiopsila Shatalkin. The morphology of the male genitalia of Xenopsila is discussed in detail, clarifying confused homologies and character polarities in the hypandrial complex. Evolutionary trends in the development of the hypandrium in the subfamily Psilinae are discussed. |
Molecular studies of Anopheles culicifacies (Diptera: Culicidae) in Sri Lanka: Sibling species B and E show sequence identity at multiple lociSinnathamby Noble SURENDRAN, Nicola J. HAWKES, Andrew STEVEN, Janet HEMINGWAY, Ranjan RAMASAMYEur. J. Entomol. 103 (1): 233-237, 2006 | DOI: 10.14411/eje.2006.025 The anomaly that Anopheles culicifacies (Diptera: Culicidae) species B is a major vector of malaria in Sri Lanka, but a non-vector in India, has been noted for several years. In 1999, a Y chromosome dimorphism associated with Plasmodium vivax infectivity within the Indian A. culicifacies species B suggested that this was itself a complex of two sibling species, B and E. A recent cytogenetic analysis shows the sympatric presence of these sibling species in Sri Lanka, a situation similar to that reported from nearby Rameshwaram Island, India. Species E, with a submetacentric Y chromosome, is a more effective vector of P. vivax than species B with an acrocentric Y chromosome. Larval karyotyping, however, is time-consuming and labour-intensive. Recently, the development of a PCR-RFLP assay distinguishing species B and E of A. culicifacies from India, based on differences in one region of the cytochrome oxidase subunit II (COII) gene, was reported. Here we show that whilst this diagnostic approach reveals polymorphism in Sri Lankan A. culicifacies, this variation is not correlated with Y chromosome karyotype. Hence this assay will not be useful for distinguishing species B and E in Sri Lanka. Further, we found no difference between the sequences of Sri Lankan specimens in any of three other regions (ITS2, D3 region of 28S rDNA, and guanylate cyclase intron) often used for species discrimination. |
Resource guarding by Ptomascopus morio: Simple parental care in the Nicrophorinae (Coleoptera: Silphidae)Seizi SUZUKI, Masahiro NAGANOEur. J. Entomol. 103 (1): 245-248, 2006 | DOI: 10.14411/eje.2006.027 Nicrophorine beetles use small vertebrate carrion for breeding resource. While Nicrophorus spp. have highly developed biparental care, no form of parental care is recorded for Ptomascopus spp. We examined two effects of resource guarding by Ptomascopus morio. The presence of parents, especially the female, reduced the number of fly larvae on chicken carrion. Parents also enhanced the survival of brood faced with predation by the rove beetle, Ontholestes gracilis. In 6 out of 20 trials, the rove beetle predators were killed by Ptomascopus morio parents. We conclude that Ptomascopus morio has a simple, and possibly primitive form of parental care. |
Increased xylem ingestion and decreased phloem ingestion in the aphid Acyrthosiphon pisum (Hemiptera: Aphididae) parasitised by Aphidius ervi (Hymenoptera: Braconidae)Claudio C. RAMÍREZ, Cristian A. VILLAGRA, Hermann M. NIEMEYEREur. J. Entomol. 103 (1): 263-265, 2006 | DOI: 10.14411/eje.2006.032 The effects of parasitisation by Aphidius ervi on the feeding behaviour of the aphid Acyrthosiphon pisum were studied. There was progressive increase in the time devoted to xylem ingestion (G waveform) and concomitant decrease in time devoted to phloem ingestion (E2 waveform) in parasitized relative to unparasitized aphids, as the time from parasitisation increased. These changes are interpreted as a way aphids compensate for metabolic changes occurring during parasitisation. |
Phenylacetaldehyde: A chemical attractant for common green lacewings (Chrysoperla carnea s.l., Neuroptera: Chrysopidae)Miklós TÓTH, András BOZSIK, Ferenc SZENTKIRÁLYI, Agostino LETARDI, Maria Rosaria TABILIO, Marcello VERDINELLI, Pietro ZANDIGIACOMO, Judit JEKISA, István SZARUKÁNEur. J. Entomol. 103 (1): 267-271, 2006 | DOI: 10.14411/eje.2006.033 At five sites in Hungary and Italy, traps baited with phenylacetaldehyde caught significantly higher numbers (10 to 100 times more) of green lacewings than unbaited traps, which demonstrates that this compound is an attractant. Traps with three bait dispensers usually caught more than those with one dispenser, but the difference was significant only at two out of five test sites. There was no difference in the numbers caught by sticky delta and funnel traps baited with phenylacetaldehyde. However, funnel traps could be adapted to catch living green lacewings. The vast majority of the specimens belonged to the Chrysoperla carnea species complex. Ch. carnea sensu lato dominated the catches at all sites. At some sites 3-11% of the insects caught were Ch. lucasina Lacroix. Phenylacetaldehyde-baited traps were attractive to both sexes, but generally more females were caught than males. Funnel traps baited with three dispensers of phenylacetaldehyde caught green lacewing adults throughout the season in Hungary. |
Winter climates and coldhardiness in terrestrial insectsWilliam J. TURNOCK, Paul G. FIELDSEur. J. Entomol. 102 (4): 561-576, 2005 Overwintering insects must avoid injury and death from the freezing of tissues and from metabolic disruptions associated with exposure to low, non-freezing temperatures. The winter climates of the world are classified in relation to insect overwintering on the basis of their minimum temperatures and the duration of the winter (when temperatures are below the thermal range for activity and development). Outside the Tropical Wet zone, the severity of exposure to cold (temperature, snowfall, duration of exposure, predictability, variability) can vary from a few days at 0°C to months below -20°C with extremes as low as -60°C. The severity of the temperature exposure may be ameliorated by the selection by insects of overwintering sites (exposed, partly-exposed, protected). The relationships among overwintering habitats, the minimum winter temperature in climatic zones, and the supercooling points (SCP) of over 350 terrestrial insects from published reports were examined. Variability in the SCP among insects within each climatic zone and habitat was wide. Among the freeze-susceptible species that overwintered in exposed or partly-protected habitats the SCP and the cold severity of climate were correlated. This was not the case for insects that overwintered in protected habitats. The SCP's of freeze-tolerant insects were generally higher than the freeze-susceptible insects, and the SCP's were not tightly linked with the cold severity of climatic zone. Insects, both freeze-susceptible and freeze-tolerant, overwintering in exposed habitats had lower SCP's than insects from habitats that offered some protection from ambient temperatures. Thirty-eight species had reports of SCP's for different geographical locations. Although there were occasionally differences in the SCP's, there was no consistent pattern of insects having lower SCP's when overwintering in colder habitats. The incidence of freeze-tolerance was higher in boreal and polar climatic zones than in climatic zones with warmer winters. Holometabola insects had a higher incidence of freeze-tolerance than hemimetabola insects. Suggestions for future research directions are outlined. |
Current knowledge on genes and genomes of phytophagous beetles (Coleoptera: Chrysomeloidea, Curculionoidea): a reviewJesús GÓMEZ-ZURITA, José GALIÁNEur. J. Entomol. 102 (4): 577-597, 2005 Fifteen years after the publication of the first genomic sequence of a phytophagous beetle, we review here the wealth of genetic and genomic information generated so far for the species-rich beetle superfamilies Chrysomeloidea (longhorn, seed and leaf beetles) and Curculionoidea (weevils and bark beetles). In this review we briefly describe the most common methods used to investigate the beetle genomes and also compile the nucleotide sequence information stored in public gene databases until December 2004. The motivations and relevance of these research initiatives are described in certain detail, distinguishing among structural and population studies, phylogenetic research, the study of genes involved in development and diapause, energetic metabolism, vegetal tissue digestion, and genes for insect resistance and defence. |
Phylogenetic evaluation of the taxonomic status of Timandra griseata and T. comae (Lepidoptera: Geometridae: Sterrhinae)Erki ÕUNAP, Jaan VIIDALEPP, Urmas SAARMAEur. J. Entomol. 102 (4): 607-615, 2005 The sterrhine loopers Timandra griseata and T. comae have been treated as distinct species since 1994. However, morphological differences between the taxa are minor and therefore their status has often been disputed. Here, we present a molecular phylogenetic study, which separates T. griseata and T. comae into different clades. Altogether, 43 Timandra specimens from eight European countries were studied. The phylogeny is based on a comparative sequence analysis of mitochondrial genes coding for the cytochrome C oxidase subunit I (COI) and NADH dehydrogenase subunit 1 (ND1). Nevertheless, a single individual of both species was assigned to the "wrong" clade. The symplesiomorphy of T. griseata and T. comae is considered to be a result of introgressive hybridization. Conditions that could lead to the hybridization of T. griseata and T. comae are discussed, as well as the likely distribution history of these taxa in Northern Europe. Results of the current analysis are in favour of retaining the species status of T. griseata and T. comae. |
Seasonal adaptations of green lacewings (Neuroptera: Chrysopidae)Michel CANARDEur. J. Entomol. 102 (3): 317-324, 2005 | DOI: 10.14411/eje.2005.049 Seasonal adaptations of green lacewings (Neuroptera: Chrysopidae) and their role in the control of aphid populations are discussed. The chrysopids of temperate zones face seasonal changes and must escape cyclic adversity. One way is via the number of broods per year. Most green lacewings are facultatively multivoltine, with the succession of generations most often regulated by photomediated diapause. Others are univoltine and some extend their life-cycle to two years in cold or dry environments. Synchronization is an important feature of seasonality, often starting in spring. In univoltine species, it is sometimes the result of subtle mechanisms, such as double contradictory signals (short plus long day lengths) for reactivation in spring, or a multi-receptivity of the preimaginal instars to photoperiod throughout a year, combined with photo-controlled and synchronized egg laying in late summer. Only one North American species is known to enter a surnumerary food-mediated diapause in summer. Every postembryonic instar may undergo diapause depending on the species. The timing and impact of the spring resumption in aphid consumption depends on their overwintering strategy. |
Intraguild predation among aphidophagous predatorsÉric LUCASEur. J. Entomol. 102 (3): 351-364, 2005 | DOI: 10.14411/eje.2005.052 Since the publication of papers by Polis et al. (1989, 1992), intraguild predation (IGP) has been considered in numerous systems and a growing number of papers have been published, demonstrating the ubiquity and the importance of this interaction. It appears that aphidophagous guilds constitute especially favourable systems for IGP. Temporal and spatial distributions of aphids promote interactions, such as IGP, among natural enemies. However, despite extensive laboratory and field studies, several questions remain to be answered: Which traits of the different protagonists of the system may promote or hamper the occurrence of IGP? How do ants tending aphids modulate the interaction? How should one consider the "sub-lethal" effects (and the defensive mechanisms) associated with the risk of IGP? May IGP disrupt or enhance aphid control? These different issues are discussed by focusing on the predatory species in the complex system of aphidophagous guilds. It appears that, first, IGP may constitute one of the main forces influencing the structure and dynamics of aphidophagous guilds, and therefore it has to be taken into account in research studies, and second, because of the ephemeral nature of aphid colonies and the great number of species belonging to aphidophagous guilds, understanding all the implications of the interaction, both direct and indirect, constitutes a very complex task. |
Induction of reproductive diapause in Hippodamia convergens (Coleoptera: Coccinellidae) hinges on prey quality and availabilityJ.P. MICHAUD, Jawwad A. QURESHIEur. J. Entomol. 102 (3): 483-487, 2005 | DOI: 10.14411/eje.2005.069 In the High Plains of western Kansas, USA, the convergent lady beetle Hippodamia convergens Guérin completes a spring generation feeding on cereal aphids in winter wheat before leaving fields in large numbers around the time of harvest. In late May, large aggregations of coccinellids form on wild sunflowers, Helianthus annuus, and certain other weeds, that appear to serve as important sources of water absorption for the beetles, and other beneficial insects, during the dry prairie summer. Adult beetles were collected from sunflower plants and held in four treatments: (1) access to water only, (2) access to sunflower stalks only, (3) eggs of Ephestia kuehniella provided ad libitum + water and, (4) greenbug, Schizaphis graminum Rondani provided ad libitum. Most females fed greenbug matured eggs in less than a week and only a few entered reproductive diapause. In contrast, more than half of the females fed Ephestia eggs, an inferior diet, entered reproductive diapause, and those that matured eggs required an average of almost three weeks to do so. Time to 50% mortality was 7 days for beetles receiving only water, and 12 days for those receiving only sunflower stalks, whereupon all survivors were fed greenbug. Even after feeding on greenbugs for a month, less than half of the surviving females in these two treatments produced eggs. We conclude that reproductive diapause is an important adaptation for improving H. convergens survival during summer when aphids are scarce, although females will forgo diapause if they have continuous access to high quality prey. |
Nearctic Achalcinae with a first Australachalcus species of North America (Diptera: Dolichopodidae)Marc A.A. POLLETEur. J. Entomol. 102 (2): 279-288, 2005 | DOI: 10.14411/eje.2005.039 Both sexes of Achalcus bicolor sp.n., Achalcus longicercus sp.n., and Australachalcus latipennis sp.n. are described as additions to the Nearctic achalcine fauna. Diagnoses of five unnamed Achalcus species represented only by females are given. A key to Nearctic males and females including 10 unnamed species is provided. The new Achalcus records considerably extend the known distribution of the genus in North America, especially in the central and eastern states. Australachalcus latipennis sp.n. is the first known Nearctic species of this predominantly Neotropical and New Zealand genus. Achalcus bicolor sp.n. from Montana, Manitoba and Ontario clearly belongs to the Achalcus flavicollis species group. The eastern Achalcus longicercus sp.n. is not included in the latter species group due to the lack of a dorsal bristle on tibia I and the absence of a preapical anterodorsal bristle on femur III in both sexes. It features postgonites with strong hook-like apical processes possibly unique to this species. The presence and number of dorsal bristles on tibia I seem to be of both diagnostic and phylogenetic relevance. All northern achalcine species were collected between June and September, whereas some Californian species were taken in May and Australachalcus latipennis sp.n. from Arizona in October - November. |
Ground beetles (Carabidae) as seed predatorsAlois HONEK, Zdenka MARTINKOVA, Vojtech JAROSIKEur. J. Entomol. 100 (4): 531-544, 2003 | DOI: 10.14411/eje.2003.081 The consumption and preferences of polyphagous ground beetles (Coleoptera: Carabidae) for the seeds of herbaceous plants was determined. The seeds were stuck into plasticine in small tin trays and exposed to beetle predation on surface of the ground. In the laboratory the effect of carabid (species, satiation) and seed (species, size) on the intensity of seed predation was investigated. The consumption of the generally preferred Cirsium arvense seed by 23 species of common carabids increased with body size. Seed of Capsella bursa-pastoris was preferred by small carabids and their consumption rates were not related to their size. The average daily consumption of all the carabid species tested (0.33 mg seeds . mg body mass-1 . day-1) was essentially the same for both kinds of seed. Because of satiation the consumption of seed of C. arvense provided ad libitum to Pseudoophonus rufipes decreased over a period of 9 days to 1/3-1/4 of the initial consumption rate. Preferences of P. rufipes (body mass 29.6 mg) and Harpalus affinis (13.4 mg) for the seeds of 64 species of herbaceous plants were determined. The small H. affinis preferred smaller seed than the large P. rufipes. Predation of seed present on the ground in the field was studied in 1999-2000, at Praha-Ruzyne (50°06´ N 14°16´E). Seeds were placed in stands of different crops as in the laboratory experiments and vertebrate predation was excluded by wire mesh cages. Pitfall traps placed near the cages revealed that carabids were the only seed predators active in the area. Rates of removal of seed of 6 weed species varied with crop, season, seed and site. Average rate of removal in June-August was 2.5 seeds.day-1.tray-1 and was smaller before and after this period. The rates of removal increased with increasing activity density of the carabids and paucity of seed from naturally occurring weeds, which may have satiated the carabids. In stands of winter wheat, millet and soybeans there were significant differences in the rates of removal of the seed of 43 herbaceous species. The field preferences were correlated with those established in the laboratory. Predation of seed on the ground in arable fields can be as high as 1000 seeds.m-2.day-1 and may selectively influence the quantity of seed of particular herb species that enters the soil seed bank. Seed predation thus may be an effective component of weed control on arable land, particularly at low weed densities. |
The effects of flooding on survivorship in overwintering larvae of the large copper butterfly Lycaena dispar batavus (Lepidoptera: Lycaenidae), and its possible implications for restoration managementColin N. NICHOLLS, Andrew S. PULLINEur. J. Entomol. 100 (1): 65-72, 2003 | DOI: 10.14411/eje.2003.014 Previous work suggests that submergence of Lycaena dispar larvae during overwintering may play a significant role in this butterfly's population dynamics. Since potential re-introduction sites in eastern England are prone to regular seasonal flooding, we further studied the species' submergence tolerance with a view to formulating management protocols conducive to larval survivorship under periodic flood conditions. Simulated flooding regimes using captive-reared larvae showed that enforced submergence has a twofold effect: firstly, a direct increase in mortality after 28 days under water and, secondly, a longer term, post-diapause increase in mortality; manifest either as an inability of larvae to resume feeding, or a failure to complete development. Additionally, there was a marked difference in the response of "early" and "late" diapause larvae; the latter generally succumbing after shorter periods under water, and suffering higher total mortalities. Behavioural investigations suggest that, if afforded the opportunity, diapausing larvae can evade submergence by climbing onto the exposed sections of partially flooded host plants. Significantly, survival on partially flooded plants was found to be comparable to that on unflooded controls. Further re-introductions of L. dispar in the U.K. will probably necessitate a direct translocation of wild Dutch stock. As the flood tolerance of this source population remains largely undetermined, and given that re-introduction site hydrology will be generally unamenable to conservation-oriented manipulation, it is recommended that restoration management be directed towards creating structural diversity in the vegetation of overwintering habitats, thereby providing potential "flood refugia" for hibernating larvae. |
Effects of host plant quality on overwintering success of the leaf beetle Chrysomela lapponica (Coleoptera: Chrysomelidae)Elena L. ZVEREVAEur. J. Entomol. 99 (2): 189-195, 2002 | DOI: 10.14411/eje.2002.027 I investigated effects of density-dependent variation in host plant quality on adult feeding and overwintering success of the leaf beetle Chrysomela lapponica L. During pre-overwintering period adult beetles were fed in the laboratory on host plants, Salix borealis, originating from (a) a site with low density population of C. lapponica, (b) a site with peak density of C. lapponica, and (c) a post-outbreak site. Beetles fed on plants from low density and peak density sites demonstrated similar performance, whereas on plants from post-outbreak site beetles fed longer, gained more weight, and experienced greater mortality during overwintering. Higher water content in these beetles suggests that the main reason for increased winter mortality is insufficient dehydration of the beetles' bodies, presumably due to low quality food. The total carbon concentration in host plant foliage explained variation in most beetle performance indices, while total nitrogen did not correlate with beetle performance. Damage-induced decrease in quality of host plants from post-outbreak sites (delayed inducible resistance, DIR), associated with increase in carbon-containing defensive compounds, was earlier found to increase larval mortality and thus contribute to the decline in population density of C. lapponica. Results of the current study suggest that DIR can also disturb pre-overwintering feeding and thus increase winter mortality of adult beetles, enhancing post-outbreak density decline. |
Molecular insights into speciation in the Agrilus viridis-complex and the genus Trachys (Coleoptera: Buprestidae)Detlef BERNHARD, Guido FRITZSCH, Pia GLÖCKNER, Claus WURSTEur. J. Entomol. 102 (4): 599-605, 2005 Species of the Agrilus viridis-complex and the genus Trachys are morphologically difficult to identify or even indistinguishable. However, all of them are ecologically clearly separated because their larvae develop in different host plants. Hitherto, it was unclear whether they represent varieties, ecological races or true species. In this paper the genetic variation and phylogenetic relationships within these groups are analysed using partial sequence data from mitochondrial genes (12S rDNA, and a fragment containing regions of ND1 and 16S rDNA). The phylogenetic analyses yielded largely congruent tree topologies and indicate that all species and varieties of the Agrilus viridis-complex belong to a monophyletic group, which is closely related to A. cuprescens. Compared to all other Agrilus-species tested, the genetic distances within the A. viridis-complex are very small. However, all varieties and species are clearly separated. Thus, our data support the view that both the members of the Agrilus viridis-complex and the species of the Trachys-group represent genetically separated taxa. |
Conservation of HP1 and methylated H3 histones as heterochromatic epigenetic markers in the holocentric chromosomes of the cabbage moth, Mamestra brassicae (Lepidoptera)Federica BORSATTI, Mauro MANDRIOLIEur. J. Entomol. 102 (4): 625-632, 2005 The methylated H3 histone and heterochromatin protein 1 (HP1) are markers of heterochromatin in several eukaryotes possessing monocentric chromosomes. In order to confirm that these epigenetic markers of heterochromatin are evolutionary conserved, the distribution of methylated H3 histones and HP1 homologues on the holocentric chromosomes of the cabbage moth Mamestra brassicae (Lepidoptera) were studied. In particular, PCR experiments with degenerated primers identified a HP1 homologue (called MbHP1) in the M. brassicae genome. Sequencing showed that the MbHP1 gene is 737 bp long including a 102 bp 5'UTR and a 635 bp coding portion (comprising an 80 bp intron). The MbHP1 peptide consisted of 184 amino acids, had a 20 kDa molecular mass and a net negative charge. At the structural level, it showed an N terminal chromo-domain and a chromo-shadow-domain at the C terminus linked by a short hinge region. At the cytogenetic level, MbHP1 was located exclusively in the heterochromatic regions of the chromosomes. The same heterochromatic regions became labelled after immuno-staining with antibodies against H3 histone methylated at lysine 9, reinforcing the hypothesis that this modified histone is essential for HP1 binding. Our data, as a whole, confirm that heterochromatic components and markers are evolutionary conserved both in mono- and holocentric chromosomes despite the difference in the distribution of heterochromatin on chromosomes. |
Exploitation of kairomones and synomones by Medetera spp. (Diptera: Dolichopodidae), predators of spruce bark beetlesJiri HULCR, Marc POLLET, Karel UBIK, Jan VRKOČEur. J. Entomol. 102 (4): 655-662, 2005 The semiochemical relationships in a predator-prey-host plant system were studied by a series of multiple-choice field assays. The studied system included predatory flies of the genus Medetera (Diptera: Dolichopodidae), the bark beetles Ips typographus and Pityogenes chalcographus (Coleoptera: Curculionidae: Scolytinae) as prey and Norwegian spruce (Picea abies) as the host plant. Of the nine species of predators collected, only M. setiventris and M. melancholica provided sufficient data for statistical analysis. The response of the predators to monoterpenic products of the host (alpha-pinene, limonene, camphor), pheromone compounds of I. typographus (S-cis-verbenol and 2-methyl-3-buten-2-ol) and a mixture of the pheromones of I. typographus and P. chalcographus were investigated. Our field trials revealed that tree volatiles plus pheromones of the prey, and a pheromone mixture of both prey species were considerably more attractive to M. setiventris and M. melancholica than the individual chemicals. Medetera seem to respond to the stage of tree decay and the intensity of bark beetle infestation via the ratios of tree volatiles and/or prey pheromones. |
Resumed forest grazing restored a population of Euphydryas aurinia (Lepidoptera: Nymphalidae) in SE FinlandKimmo SAARINEN, Juha JANTUNEN, Anu VALTONENEur. J. Entomol. 102 (4): 683-690, 2005 In 1996, an old forest pasture grazed from the 1960s to 1988 was restored by coppicing, fencing and grazing by cattle to protect a local population of the endangered butterfly Euphydryas aurinia. An adjoining ungrazed meadow provided a control. In the first years, the butterfly became almost extinct due to the nearly complete consumption of the host plant of the larva, Succisa pratensis, by cattle. The butterfly population quickly recovered when the grazing pressure was lowered. Thus, the intensity of management should be adjusted by continuous monitoring of the target species. In the 2000s, the annual population was about 50 butterflies, but marked fluctuations took place, probably caused by natural factors. Grazing benefited the meadow flora and improved the habitat of butterflies in general. Extensive forest grazing clearly has the potential for enhancing biodiversity. The value of the experiment is, however, limited because only a single pair of meadows was available for comparison. In the future, it will be even more difficult to arrange a similar experiment due to the great decline in the numbers of traditional meadows and forest grazing in SE Finland. |
Foraging activity and demographic patterns of two termite species (Isoptera: Rhinotermitidae) living in urban landscapes in southeastern BrazilAlberto ARAB, Ana Maria COSTA-LEONARDO, Fabiana Elaine CASARIN, André De Camargo GUARALDO, Ricardo C. CHAVESEur. J. Entomol. 102 (4): 691-697, 2005 Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rhinotermitidae) are important pests in southeastern Brazil causing serious economic damage. In this study we determined the demographic patterns and foraging activity of these species using mark-release-recapture and the consumption of wooden stakes. Using both the weighted mean and Lincoln index methods, population estimates ranged from ≈ 0.57 to 1.99 million individuals for C. gestroi and from ≈ 0.20 to 1.37 million for H. tenuis. Territory size of the colonies ranged from 172.5 to 5235 m2 for C. gestroi and from 16 to 40 m2 for H. tenuis. Our results also indicate that foraging activity was dependent on the minimum temperature; however, the existence of a compensation strategy in the foraging activities may permit foragers to exploit food sources under different environmental conditions. |
Adult demography, dispersal and behaviour of Brenthis ino (Lepidoptera: Nymphalidae): how to be a successful wetland butterflyKamil ZIMMERMANN, Zdeněk FRIC, Ladislava FILIPOVÁ, Martin KONVIČKAEur. J. Entomol. 102 (4): 699-706, 2005 Continent-wide loss of traditionally managed humid meadows is raising concern for associated butterfly specialists across Europe. However, not all species associated with this biotope are threatened, and the Lesser Marbled Fritillary (Brenthis ino) has even spread locally. We employed mark-recapture and transect walks to study its population structure and patterns of landscape occupancy in a hilly region of western Bohemia, Central Europe, to determine which life history or demography traits might be responsible for its success. A population studied by mark-recapture harboured more than 1000 individuals and was interconnected with other populations. This was further supported by a fit of the inverse power function to dispersal data. Observations of adult behaviour revealed a broad host plant range: at least three species of plants were used by the single population. On a landscape scale, the butterfly exhibited an aggregated distribution matching its host plants. It was associated with the distribution of characteristic plants and butterflies of semi-natural humid meadows, but its frequency exceeded those of other humid grasslands specialists. The relatively broad host range coupled with varying biotope requirements of individual host plant species results in a wide biotope range for the butterfly, explaining its persistence in fragmented Central European landscapes. |
Detection of predation on Euzophera pingüis (Lepidoptera: Pyralidae) using an enzyme-linked immunosorbent assayEstefanía RODRÍGUEZ, Carlos LOZANO, Mercedes CAMPOSEur. J. Entomol. 102 (4): 793-796, 2005
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Natural prey of the jumping spider Menemerus taeniatus (Araneae: Salticidae)Elchin F. HUSEYNOVEur. J. Entomol. 102 (4): 797-799, 2005 The natural prey of the jumping spider Menemerus taeniatus (L. Koch, 1867) was studied on the Absheron Peninsula, Azerbaijan. The percentage of specimens of M. taeniatus found feeding was low (10.7%). This investigation showed that M. taeniatus is a polyphagous predator feeding on a wide range of arthropods, including representatives of eight arthropod orders. The primary food of M. taeniatus was Diptera and Lepidoptera, which collectively made up about two thirds of total prey. The length of prey killed by M. taeniatus ranged between 1.10 and 13.00 mm (mean 6.14 mm), which is between 15.2 and 216.7% (mean 90.3%) of the length of their captors. Most frequently taken prey (50%) were medium-sized arthropods varying between 50-100% of the spiders' body length. |
Anthropogenic induced changes in nesting densities of the dune-specialised digger wasp Bembix rostrata (Hymenoptera: Sphecidae)Dries BONTEEur. J. Entomol. 102 (4): 809-812, 2005 Data on nesting densities of Bembix rostrata, a digger wasp inhabiting dynamic coastal dunes, were used to document the detrimental effects of trampling by cattle and vacationers. Both types of disturbance resulted in similar sand displacement and prey availability. Nesting densities of Europe's largest digger wasp declined dramatically with increasing trampling, probably below the critical population size. Hence, additional human disturbance, although resulting in similar environmental conditions compared to natural disturbance, significantly affected local population sizes. As a result, anthropogenic has to be avoided disturbance in order to restore or conserve natural dynamics and efforts to restore natural dynamics in a more natural way should be promoted. Although this is here only documented for one, large specialised invertebrate, the application of traditional management techniques, such as grazing by large herbivores, within newly evolved landscapes may introduce new pressures that affect pre-adapted species to natural disturbances negatively within short time spans. |
Foraging in a complex environment - semiochemicals support searching behaviour of the seven spot ladybirdJan PETTERSSON, Velemir NINKOVIC, Robert GLINWOOD, Michael A. BIRKETT, John A. PICKETTEur. J. Entomol. 102 (3): 365-370, 2005 | DOI: 10.14411/eje.2005.053 Knowledge of semiochemically-mediated behavioural mechanisms of the seven-spot ladybird, Coccinella septempunctata L., is limited but sufficient to encourage further studies in the behavioural ecology of this well known insect. Recent findings on semiochemicals are discussed in relation to the main traits in the ecology of C. septempunctata. A putative autumn aggregation pheromone, and effects of allelobiotic plant interactions on habitat preferences of adults are reported. Mechanisms for interaction between an aphid alarm pheromone and plant substances are described, and the kairomonal functions of volatiles from C. septempunctata on the parasitoid Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae) are discussed. Considering the polyphagous diet of C. septempunctata, investigations on the importance of associative learning of chemical cues in foraging behaviour, and further studies on interactions with other third trophic level organisms will provide interesting lines of research. |
On the assessment of prey suitability in aphidophagous CoccinellidaeJ.P. MICHAUDEur. J. Entomol. 102 (3): 385-390, 2005 | DOI: 10.14411/eje.2005.055 Empirical protocols for assessing the suitability of prey for aphidophagous coccinellids are examined and a modified scheme of categorization is presented. It is argued that prey suitability should be assessed independently for larval development and adult reproduction because of potentially divergent nutritional requirements between these life stages. A scheme is proposed for assessing prey suitability for larval development using conspecific eggs as a reference diet against which diets of various prey types can be compared both within and among coccinellid species. Among suitable prey (those that support ca. 100% survival of larvae to the adult stage), those that promote faster development and yield larger adults relative to a conspecific egg diet are considered "optimal" for larvae. Prey that yield viable adults with similar or reduced adult weight after a similar or extended period of development relative to a diet of conspecific eggs are classified as "adequate". Prey are "marginal" if they support the survival of some larvae, but significantly less than 100%. Supplementary water should be provided with any non-aphid diet (e.g. pollen and alternative sources of animal protein) given the potential for food-specific diet-drought stress interactions. For adults, suitable prey are classified as "adequate" if they support the production of viable eggs when fed as a monotypic diet, or "marginal" if they merely prolong adult life relative to a water source. Prey that comprise an optimal or adequate diet for both larval development and adult reproduction are termed "complete" and these can be indexed for relative suitability according to derived estimates of rm. Potential sources of error in diet evaluation studies are identified and discussed. |
Evolution of prey specialization in aphidophagous syrphids of the genera Melanostoma and Platycheirus (Diptera: Syrphidae) 1. Body size, development and prey traitsFrank DZIOCKEur. J. Entomol. 102 (3): 413-421, 2005 | DOI: 10.14411/eje.2005.059 Interactions between syrphid predators and their prey are poorly known. The adaptations of syrphids to aphid defences and the consequences for the evolution of life history traits in these predators especially are mostly unstudied. This is the first of two papers investigating the evolution of prey specialization in aphidophagous hoverflies. The study focuses on two questions: (1) Are differences in the body size of syrphid predators reflected in differences in the size of their prey? (2) Are differences in body size, body mass and development time of the syrphid predators correlated with the defence strategies of their aphid prey (e.g. mobility, toxicity)? Platycheirus clypeatus (Meigen, 1822), Platycheirus fulviventris (Macquart, 1829), Melanostoma mellinum (Linnaeus, 1758), and Melanostoma scalare (Fabricius, 1794), which differ considerably in their prey specialization, but are closely related, were chosen as model species. Life history data for these syrphids came from a laboratory study, and that for the aphids from a literature survey. These syrphid species can be arranged on a gradient of increasing prey specialization, from 32 prey species for the generalist M. mellinum and only 3 for the specialist P. fulviventris. Differences in prey specialization were even more evident when the defence ability of the various species of aphid prey was considered. For instance, the specialization on ant-attended aphids in M. scalare. Larvae exhibited a one or two weeks diapause which made the determination of developmental time imprecise. Body size of the predators was not reflected in that of their aphid prey. The postulated relationship between body size of the predator and the defence strategies of their prey was not supported by our data. A comparison of a wider range of syrphid species from different taxonomic groupings together with a phylogenetic correction procedure might reveal clearer trends. The second part of this paper (Dziock, in prep.) will investigate the correlation between prey specialization and reproductive strategies (i.e. clutch size, egg size and number) and will put the results into a broader framework. |
Temporal stability of morph frequency in central European populations of Adalia bipunctata and A. decempunctata (Coleoptera: Coccinellidae)Alois HONĚK, Zdeňka MARTINKOVÁ, Stano PEKÁREur. J. Entomol. 102 (3): 437-442, 2005 | DOI: 10.14411/eje.2005.062 In central Europe Adalia bipunctata (L.) occurs in two main colour morphs (typical, melanic), and A. decempunctata (L.) occurs in 3 morphs (spotted, chequered, dark). Temporal variation in the relative frequency of morphs was recorded in populations of the Czech Republic where geographic variation in morph frequency is low. Seasonal trends were investigated in samples collected by a light-trap run daily from March to November for 14 years. In A. bipunctata the melanic form was more abundant in autumn than in spring but the difference was not significant. In A. decempunctata morph proportions did not change seasonally. Samples were also collected by sweepnet from stands of many plant species. In both Adalia species the morph proportions did not differ significantly among collections made on different plants. Long-term changes in morph proportions were analysed by pooling annual samples over all host plants. In A. bipunctata, sampled in 15 years between 1971-2004, there was no significant change in proportion of typical (90.1%) and melanic (9.9%) forms. In A. decempunctata, sampled in 12 years between 1976-2004, the proportions of "spotted" (mean over the years 29.4%), "chequered" (42.2%) and "dark" (21.3%) morphs varied between years. There was a trend toward an increasing proportion of the spotted form in the 2000s compared to the 1970s and 1980s. |



