Many species of carabid beetles are important pre- and post-dispersal seed feeders of herbaceous plants. Here we summarise data from dissections, field observations, rearing and "cafeteria" experiments on 55 granivorous and 188 omnivorous species that occur in Italy. We tested the hypothesis that seed feeding carabids are restricted to taxa with pronounced morphological adaptations for manipulating and crushing seeds in both the larval and adult stages. The feeding guilds of carabids were rearranged into the following groups: (i) strict predators with long mandibles and predaceous larvae, often depending also on non-prey food; (ii) omnivorous species with stout mandibles and larvae of a seed-eating morphotype; (iii) granivorous species, feeding only on seeds with larvae sometimes of the scarabeoid c-form type. The seed feeding carabids in the Italian fauna belong to the tribe Zabrini (Amara and Zabrus genera) and to all the Harpalinae (sub)tribes, from Anisodactylini to Ditomina. The time of reproduction seems to be associated with habitat preference; wetland or dry open land, rather than true granivorous versus omnivorous habits, but in stenophagous seed feeders, a phenological coincidence with particular plants is sometimes recorded., Federica Talarico, Anita Giglio, Roberto Pizzolotto, Pietro Brandmayr., and Obsahuje bibliografii
Semi-natural habitats are key components of rural landscapes because they shelter a significant number of overwintering arthropods that are beneficial to agriculture. However, woodlots are semi-natural habitats with high patch-level heterogeneity and this aspect has been poorly studied. The purpose of this study was to determine the influence of woodlot heterogeneity on overwintering ground beetles. Woodlot heterogeneity was characterized in terms of distance from the woodlot boundary and date of the most recent logging operation. We used emergence traps to quantify the population density of ground beetles that overwintered in the different parts of the woodlot. In woodlot edges the densities and species richness of ground beetles were significantly higher than in the rest of the woodlot. Ground beetles that are active in crop fields overwintered in the edges but not in the inner zone of the woodlot. Species assemblages of ground beetles overwintering in the edges were highly diverse. The date of the most recent logging operation did not explain the distribution of ground beetles that overwintered in the woodlot. Our results show that woodlots, and in particular their edges, are used as a winter shelter by ground beetles that spend part of their life in crops, which potentially favours biological control in adjacent crop fields. and Anthony Roume, Annie Ouin, Laurent Raison, Marc Deconchat.
Classical biological control is an important means of managing the increasing threat of invasive plants. It constitutes the introduction of natural enemies from the native range of the target plant into the invaded area. This method may be the only cost-effective solution to control the rapidly expanding common ragweed, Ambrosia artemisiifolia, in non-crop habitats in Europe. Therefore, candidate biocontrol agents urgently need to be assessed for their suitability for ragweed control in Europe. A previous literature review prioritized the host-specific leaf beetle Ophraella slobodkini as a candidate agent for ragweed control in Europe, whereas it rejected its oligophagous congener O. communa. Meanwhile, O. communa was accidentally introduced and became established south of the European Alps, and we show here that it is expanding its European range. We then present a short version of the traditional pre-release risk-benefit assessment for these two candidate agents to facilitate fast decision-making about further research efforts. We selected two complementary tests that can be conducted relatively rapidly and inform about essential risks and benefits. We conducted a comparative no-choice juvenile performance assay using leaves of ragweed and sunflower, the most important non-target plant, in Petri dishes in climatic conditions similar to that in the current European range of O. communa. This informs on the fundamental host range and potential for increasing abundance on these host plants. The results confirm that O. slobodkini does not survive on, and is hence unlikely to cause severe damage to sunflower, while O. communa can survive but develops more slowly on sunflower than on ragweed. In parallel, our species distribution models predict no suitable area for the establishment of O. slobodkini in Europe, while O. communa is likely to expand its current range to include a maximum of 18% of the European ragweed distribution. Based on this early assessment, the prioritization and further assessment of O. slobodkini seem unwarranted whereas the results urgently advocate further risk-benefit analysis of O. communa. Having revealed that most of the European area colonized by ragweed is unlikely to be suitable for these species of Ophraella we suggest the use of such relatively short and cheap preliminary assessment to prioritise other candidate agents or strains for these areas., Suzanne T. E. Lommen, Emilien F. Jolidon, Yan Sun, José I. Bustamante Eduardo, Heinz Müller-Schärer., and Obsahuje bibliografii
The pine bark beetle, Dendroctonus armandi, is a native pest restricted to forests in the Qinling Mountains in China. There was an outbreak of this species there that affected over 0.36 million hectares of pine forest. We hypothesized that there are differences between the numbers of beetles captured by traps baited with various combinations of candidate semiochemicals extracted from the hindguts of D. armandi. In order to determine whether a better operational lure could be developed for D. armandi, we analyzed the volatiles in extracts of the hindgut of D. armandi and tested various combinations of candidate semiochemicals. The GC-MS and GC-FID analyses of volatiles in the extracts of the hindguts of D. armandi collected at different stages of the attack revealed that they are mainly a-pinene, b-caryophyllene and (+)-3-carene with minor amounts of myrcene, limonene, verbenol and verbenone. We tested various combinations of these candidate semiochemicals in order to determine an optimal blend. Our results suggest that the addition of b-caryophyllene to either a-pinene, or blends of a-pinene and other candidate semiochemicals, significantly enhanced the attractiveness of the lures for D. armandi. Field trapping experiments indicated that the blends that included b-caryophyllene, myrcene and other candidate semiochemicals resulted in significantly higher trap catches (161–243% higher) than a-pinene alone. Therefore, a simple lure consisting of a-pinene and b-caryophyllene would be an optimal blend for D. armandi. We conclude that this blend of semiochemicals may provide a better method of reducing the numbers of D. armandi in forest ecosystem., Shou-An Xie, Shu-Jie LV., and Obsahuje seznam literatury
The tenebrionid beetles on 25 circum-Sicilian islands were studied to determine the influence of island geographical and landscape features on three main intercorrelated biogeographical patterns: (1) species richness, studied using species-area and species environment relationships, (2) species assemblage composition, investigated using Canonical Correspondence Analysis (CCA), and (3) inter-site faunal similarity, investigated using Canonical Correlation Analysis (CANCOR) applied to multidimensional scaling of inter-island faunal dissimilarities. Species richness was mostly influenced by island area and landscape heterogeneity (expressed using various indices of diversity based on land cover categories). When species identities were considered in the CCA, no substantial effect of landscape was detected. Current island isolation did not have a strong influence on species richness, but has a distinct effect in determining species assortments on the remotest islands. Historical influences of Pleistocene landbridge connections were not detectable in species richness relationships using geographical variables in species richness analyses or in assemblage gradients in the CCA, but emerged distinctly from inter-island similarities in the CANCOR. and Simone Fattorini.
Satellite DNAs are the major repetitive DNA components in eukaryotic genomes. Although satellite DNA has long been called "parasite DNA" there is substantial evidence that it could be associated with some functions of chromosome biology. Ladybird beetles (Coccinellidae) are one of the largest and most important groups of beetles. Many ladybirds are of economic interest as biological control agents because they eat some agricultural pests such as aphids and scale insects. However, other species are phytophagous and can damage crops. Despite the ecological importance of the latter group there are no studies on their satellite DNA. A satellite DNA family was isolated and characterized in the ladybird Henosepilachna argus. This satellite DNA is organized in tandem repeats of 658 bp and is A + T rich (67.3%). The recorded high sequence conservation of the monomers together with the detection of putative gene conversion processes indicate concerted evolution. Reverse transcription polymerase chain reaction (RT-PCR) revealed that this satellite DNA is transcribed and in situ hybridization its location in the subtelomeric regions of all chromosomes except the long arm of the X chromosome. The presence of this satellite DNA in other species of the genus Henosepilachna and Epilachna was also tested using PCR. The results indicate that this satellite DNA sequence is so far specific to H. argus., Pablo Mora, Jesús Vela, Areli Ruiz-Mena, Teresa Palomeque, Pedro Lorite., and Obsahuje bibliografii
In the present work, we have characterized the chromosomes of 13 Cassidinae beetles, belonging to four tribes, the broad aim being to increase the cytogenetic data and establish the mechanisms involved in chromosome evolution of this subfamily, which appear to be conserved karyotypically, i.e. 2n = 16 + Xyp. The analysis of mitotic and meiotic cells revealed a high diversity of diploid numbers (2n = 18, 2n = 22, 2n = 26, 2n = 32, 2n = 36, 2n = 40, 2n = 42), and the presence of sex chromosome system of the Xyp type in most species, with the exception of two representatives that exhibited Xyr and XY systems. C-banding showed constitutive heterochromatin predominantly localized in the pericentromeric region of the chromosomes, but differences regarding the number of chromosomes with positive C-bands, intensity of the blocks, and presence of additional bands in autosomes and/or sex chromosomes were observed among the species investigated. Our data revealed that the karyotype 2n = 16 + Xyp does not occur in all 13 tribes of the Cassidinae characterized cytogenetically, seeming to be only a shared feature among the species of the Cassidini. Variations in the C-band pattern, mainly in closely related species, suggest that the interspecific karyotype diversification occurred as a result of changes in the quantity and distribution of constitutive heterochromatin. The occurrence of the Xyp sex chromosome system in the tribe Mesomphaliini, which showed the highest diversity of simple and multiple systems among the coleopteran as a whole, reinforces the view that derived systems originated by chromosome rearrangements involving the Xyp ancestral system., Amália T. Lopes, Flávia R. Fernandes, Marielle C. Schneider., and Obsahuje bibliografii
Fifteen different mitochondrial haplotypes of the mtDNA gene COI encoding cytochrome C oxidase subunit I were identified in the 127 individuals of Adalia bipunctata studied. Two mitochondrial haplotypes, H9 and H10, differed greatly from the others. The mitochondrial polymorphism in A. bipunctata is ancient, though its age remains to be evaluated. It is shown that mitochondrial haplotypes H9 and H10 and others coexisted in the original population of A. bipunctata before it spread throughout Eurasia from Western Europe to the Baikal Area, and before the differentiation of the subspecies A. bipunctata fasciatopunctata, which differs from the European form in its elytral pattern. In order to evaluate the possible origin of the ancient mitochondrial haplotypes in the gene pool of A. bipunctata sequences of the mtDNA gene COI and of the rRNA second internal transcribed spacer of the four species of Adalia: A. bipunctata, A. decempunctata, A. frigida and A. tetraspilota, were compared. It is suggested that infection with Rickettsia had an important role in the preservation of the mitochondrial haplotypes H9 and H10 during the evolution of Adalia., Ilya Zakharov, Elena Shaikevich., and Obsahuje seznam literatury
A positive correlation between the parental effort of a male and female should promote stable biparental care. In order to prevent infanticide male and female burying beetles are said to guard against intruders cooperatively and the presence of a male partner is said to increase the probability of successful defence. However, this hypothesis is supported only by indirect evidence. In this study this hypothesis is tested by direct observation. Whether the intruder was male or female, contests between the same and the opposite sex occurred, although there were few contests between resident females and intruding males. In addition, resident pairs tended to win irrespective of the sex of the intruder, although it is reported that among burying beetles large beetles usually win intra-sexual contests. In the presence of a partner, a small resident can defend a carcass against a large con-sexual intruder. These results suggest that by means of biparental cooperation burying beetles can repel stronger intruders and supports the hypothesis that the threat of infanticide is the primary explanation for extended biparental care in these beetles. and Seizi Suzuki.
The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe. In the present study we test this idea of a short, early period of diapause by sampling beetles from their hibernation sites immediately after their migratory flights in October, subsequently keeping them in outdoor cages, and then, after certain time-intervals, measuring the pre-oviposition time under optimal egg-laying laboratory conditions at 25°C. We did this at both short (12L) and long (16L) photoperiods, since a photoperiodic response is an indicator of true diapause, rather than quiescence. A significant, albeit small, difference in pre-oviposition period between the two photoperiods, which disappears in December, corroborates our earlier hypothesis that the ladybirds are in a state of diapause until mid-December. Compared with that of native ladybirds the diapause of H. axyridis generally is relatively short and weak; moreover, it appears to have become shorter over the last decade. This flexibility in diapausing behaviour may be an important factor that contributes to the invasive success of H. axyridis., C. Lidwien Raak-Van Den Berg ... [et al.]., and Obsahuje seynam literatury