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Beetle Species (beetle + species)
Kinds of Beetle Species Selected AbstractsVertical Stratification Responses of an Arboreal Dung Beetle Species to Tropical Forest Fragmentation in MalaysiaBIOTROPICA, Issue 5 2010Daniel J. Tregidgo ABSTRACT Little is known about how arboreal arthropods respond to forest disturbance. We assessed how rain forest fragmentation affected the vertical stratification of arboreal dung beetles in Peninsular Malaysia. An arboreal dung beetle species (Onthophagus sp.) moved closer to the forest floor in smaller fragments, suggesting a downward shift in its foraging possibly in response to fragmentation. [source] How does the knowledge about the spatial distribution of Iberian dung beetle species accumulate over time?DIVERSITY AND DISTRIBUTIONS, Issue 6 2007Jorge M. Lobo ABSTRACT Different distribution maps can be obtained for the same species if localities where species are present are mapped at different times. We analysed the accumulation of information over time for a group of dung beetle species in the Iberian Peninsula. To do this, we used all available information about the distribution of the group as well as data on selected species to examine if the process of discovery of species distribution has occurred in a climatically or spatially structured fashion. Our results show the existence of a well-defined pattern of temporal growth in distributional information; due to this, the date of capture of each specimen can be explained by the environmental and spatial variables associated to the collection sites. We hypothesize that such temporal biases could be the rule rather than the exception in most distributional data. These biases could affect the weighting of environmental factors that influence species distributions, as well as the accuracy of predictive distribution models. Systematic surveys should be a priority for the description of species geographical ranges in order to make robust predictions about the consequences of habitat and climate change for their persistence and conservation. [source] Scale dependence of effective specialization: its analysis and implications for estimates of global insect species richnessDIVERSITY AND DISTRIBUTIONS, Issue 1 2007Jon C. Gering ABSTRACT Estimates of global insect species richness are sometimes based on effective specialization, a calculation used to estimate the number of insect species that is restricted to a particular tree species. Yet it is not clear how effective specialization is influenced by spatial scale or characteristics of the insect community itself (e.g. species richness). We investigated scale dependence and community predictors of effective specialization using 15,907 beetles (583 species) collected by insecticide fogging from the crowns of 96 trees (including 32 Quercus trees) located in Ohio and Indiana. Trees were distributed across 24 forest stands (,1 ha) nested within six sites (,10,100 km2) and two ecoregions (> 1000 km2). Using paired-sample randomization tests, we found that effective specialization (fk) exhibited negative scale-dependence in early (May,June 2000) and late (August,September 2000) sampling periods. Our average effective specialization (F) values , those that are comparable to Erwin's (1982) estimates , ranged from 19% to 97%, and increased as spatial scale decreased. We also found that beetle species richness and the number of shared beetle species across host trees were significant and consistent negative predictors of F. This shows that increases in spatial scale, species richness, and the number of trees (and/or tree species) all coincide with decreases in effective specialization. Collectively, our results indicate that estimates of global insect species richness based on effective specialization at a single spatial scale are overestimating the magnitude of global insect species richness. We propose that scale dependence should be promoted to a central concept in the research program on global estimates of species richness. [source] Diversity, distinctiveness and conservation status of the Mediterranean coastal dung beetle assemblage in the Regional Natural Park of the Camargue (France)DIVERSITY AND DISTRIBUTIONS, Issue 6 2001Jorge Miguel Lobo Abstract. The Mediterranean region as a whole has the highest dung beetle species richness within Europe. Natural coastal habitats in this region are among those which have suffered severe human disturbance. We studied dung beetle diversity and distinctiveness within one of the most important coastal protected areas in the west Euro-Mediterranean region (the regional Park of Camargue, southern France) and made comparisons of dung beetle assemblages with other nearby Mediterranean localities, as well as with other coastal protected area (Doñana National Park, Spain). Our finding showed that: (1) The species richness of coastal habitats in the Camargue is low and only grasslands showed a similar level of species richness and abundance to inland habitats of other Mediterranean localities. The unique habitats of the coastal area (beaches, dunes and marshes) are largely colonized by species widely distributed in the hinterland. (2) In spite of their low general distinctiveness, dune and marsh edges are characterized by the occurrence of two rare, vulnerable, specialized and large roller dung beetle species of the genus Scarabaeus. As with other Mediterranean localities, current findings suggest a recent decline of Scarabaeus populations and the general loss of coastal dung beetle communities in Camargue. (3) The comparison of dung beetle assemblages between the Camargue and Doñana shows that, in spite of the low local dung beetle species richness in the Camargue, the regional dung beetle diversity is similar between both protected areas. Unique historical and geographical factors can explain the convergence in regional diversity as well as the striking divergence in the composition of dung beetle assemblages between both territories. [source] Ground beetle species (Coleoptera, Carabidae) associations with land cover variables in northern England and southern ScotlandECOGRAPHY, Issue 4 2004M. D. Eyre Distribution data concerning 172 ground beetle species derived from 1145 pitfall trap sites in northern England and southern Scotland were used to assess the relationship between species distribution and 12 satellite-derived land cover variables at the regional scale. A number of species were strongly associated with one cover type and negatively with others. The major variation was for preferences for covers in upland or lowland parts of the region. Other distinct preferences for some species were covers such as those at the coast whilst a number of common species showed no strong preference for any cover variable. The synthesis of ground beetle species distribution and satellite-derived cover data is discussed in relation to environmental assessment and change. [source] Spatial and temporal organisation of the pre-dispersal seed predator guild in a perennial legume, Vicia tenuifoliaECOLOGICAL ENTOMOLOGY, Issue 2 2006Árpád Szentesi Abstract., 1. The variability of species combinations and membership assembly patterns in an insect pre-dispersal seed predator guild were studied at various spatial and temporal resolutions using presence/absence and abundance data in null models. The guild consists of seven beetle species (four bruchids and three curculionids) and one moth species that live on a perennial vetch, Vicia tenuifolia Roth (Leguminosae). 2. The seed predator guild varied considerably in the number of members and species combinations in space and time, and, contrary to expectations, there was no evidence of interspecific competition among guild members, supporting the view that other processes, including chance events, could contribute to guild formation. 3. It is concluded that, apart from the possibility of stochastic co-occurrence, it is the narrow host specialisation that constrains seed predator members to participate in the guild, and small differences in habitat preference can also lead to spatial and temporal variation. [source] Is the matrix a sea?ECOLOGICAL ENTOMOLOGY, Issue 1 2005Habitat specificity in a naturally fragmented landscape Abstract., 1. Metapopulation and island biogeography theory assume that landscapes consist of habitat patches set in a matrix of non-habitat. If only a small proportion of species conform to the patch,matrix assumptions then metapopulation theory may only describe special cases rather than being of more general ecological importance. 2. As an initial step towards understanding the prevalence of metapopulation dynamics in a naturally fragmented landscape, the distribution of beetle species in three replicates of three habitat types was examined, including rainforest and eucalypt forest (the habitat patches), and buttongrass sedgeland (the matrix), in south-west Tasmania, Australia. 3. Ordination methods indicated that the buttongrass fauna was extremely divergent from the fauna of forested habitats. Permutation tests showed that the abundance of 13 of 17 commonly captured species varied significantly among habitats, with eight species confined to eucalypts or rainforest, and three species found only in buttongrass. Approximately 60% of species were confined to forested habitat implying that metapopulation theory has the potential to be very important in the forest,buttongrass landscape. 4. Although floristically the rainforest and eucalypts were extremely distinct, the beetle faunas from eucalypts and rainforests overlapped substantially. Therefore rainforest patches connected by eucalypt forest represent continuous habitat for most species. 5. Other studies report a wide range of values for the proportion of patch-specific species in fragmented landscapes. Understanding the environmental or historical conditions under which a high proportion of species become patch specialists would help to identify where spatial dynamic theory may be especially applicable, and where habitat loss and fragmentation poses the greatest threat to biodiversity. [source] Dung beetles in a Central Amazonian rainforest and their ecological role as secondary seed dispersersECOLOGICAL ENTOMOLOGY, Issue 3 2002Ellen Andresen Abstract 1. The role of several factors that affect the composition of the dung beetle assemblages in an Amazonian rainforest was quantified, together with the effect of these factors on the role that dung beetles play as secondary seed dispersers. 2. A total of 61 dung beetle species was captured during 3360 h of trapping. During nocturnal trapping periods, more dung beetles, of larger mean size, and more species were captured per trap than during diurnal trapping periods. 3. During the rainy season, more dung beetle species were captured per trap than during the dry season, but the number of individuals and their mean size did not vary between seasons. 4. Bait size had a significant effect on the mean number of beetles and mean number of species but not on mean beetle size. As bait size increased from 5, 10, 25, to 50 g, more beetles and more species were captured per trap. 5. Between 6 and 73% of plastic beads, used as seed mimics, were buried by dung beetles at depths that ranged from 0.5 to 7 cm. Both the proportion of beads buried and burial depth decreased with increasing bead size, and increased with increasing amounts of dung surrounding each bead (5, 10, and 25 g). 6. The proportion of buried seeds for three species varying in size between 5 and 27 mm, increased with increasing dung beetle size, using beetles of seven sizes, varying between 10 and 25 mm. 7. Seeds surrounded by dung were buried more often and more deeply when placed on the forest floor during the late afternoon than when placed during the early morning. Seeds were also buried more often when placed on the forest floor during the rainy season than when placed during the dry season, but season had no effect on burial depth. 8. Forests in Central Amazonia hold a rich dung beetle community that plays an active role in secondary seed dispersal, and consequently in plant regeneration. The interaction between seeds and beetles is complex because it is affected by many factors. [source] First records of Leiodytes nicobaricus (Redtenbacher) and Platambus stygius (Régimbart) in Korea (Coleoptera: Dytiscidae)ENTOMOLOGICAL RESEARCH, Issue 1 2008Dae-Hyun LEE Abstract Two dytiscid beetle species, Leiodytes nicobaricus (Redtenbacher) and Platambus stygius (Régimbart), are identified for the first time in Korea. Diagnoses, habitus and scanning electron microscopy photographs, and line drawings of the diagnostic characters are provided. [source] External exoskeletal cavities in Coleoptera and their possible mycangial functionsENTOMOLOGICAL SCIENCE, Issue 1 2010Vasily V. GREBENNIKOV Abstract This paper reviews the occurrence of external exoskeletal cavities in beetles and provides critical reassessment of their possible mycangial function. In most reported cases, the decision to attribute mycangial function to exoskeletal cavities was based solely on the combination of two factors: (i) observation of these cavities on beetle's body; and (ii) knowledge that this particular beetle species uses fungi as a food source. Such reasoning resulted in the assumption, occasionally premature and not supported by other evidence, that exoskeletal pits in the following families may function as mycangia: Rhysodidae, Ptiliidae, Staphylinidae, Hybosoridae, Scarabaeidae, Derodontidae, Ptinidae, Jacobsoniidae, Boganiidae, Cryptophagidae, Endomychidae, Erotylidae, Latridiidae, Nitidulidae, Phloeostichidae, Silvanidae, Sphindidae, Pyrochroidae, Anthribidae, Attelabidae and Curculionidae. We conclude that only two beetle families include species with adequately documented cases of external exoskeletal mycangia: (i) Curculionidae (some Scolytinae and Platypodinae); and (ii) the structurally complex mycangia of Attelabidae (Euops females). One or more species of Sphindidae, Erotylidae, Silvanidae, and Latridiidae have likely functional mycangia. Exoskeletal pits with uncertain function are additionally reported from the following families: Cupedidae, Ommatidae, Lepiceridae, Carabidae, Histeridae, Hydraenidae, Leiodidae, Elmidae, Artematopodidae, Throscidae, Elateridae, Rhinorhipidae, Biphyllidae, Cerylonidae, Cyclaxyridae, Monotomidae, Mycetophagidae and Zopheridae. We also discuss the transport of fungal spores and conidia by waxy exudates or debris build up on beetle exoskeleton, as well as their passive attachment to the body. [source] Interpopulation differences in the mandible size of the coastal tiger beetle Lophyridia angulata associated with different sympatric speciesENTOMOLOGICAL SCIENCE, Issue 3 2004Aya SATOH Abstract The coastal tiger beetle Lophyridia angulata (Fabricius) co-occurs with one or two tiger beetle species at any one locality (in a sandy beach habitat) along the Japan Sea coast of Honshu, from eastern to southern Kyushu, and on Tanega-shima, an island south of Kyushu, in Japan. Lophyridia angulata displays sexual dimorphism in mandible length (the mandible is longer in females), and shows large interpopulation differences in mandible size. We analyzed variation in mandible length between L. angulata populations associated with three different sympatric species, and examined morphological differences that may have resulted from interaction with these other species. Lophyridia angulata showed a significant size shift towards larger mandibles in a population that co-occurred with Cicindela lewisii, which has a similar mandible length to that of L. angulata, as compared to a neighboring population of L. angulata that co-occurred with another species. This pattern may be interpreted as a type of character displacement associated with food resource competition. Males in L. angulata populations co-occurring with Chaetodera laetescripta showed little variation in mandible length, as compared to other populations. These males may experience some pressure from C. laetescripta and from conspecific females. We found no significant changes in mandible length or in size variation of L. angulata before and 20 years after the extinction of Abroscelis anchoralis at one site historically co-inhabited by both species; that is, we did not detect a character release over the 20 years. [source] EVOLUTION OF SUBTERRANEAN DIVING BEETLES (COLEOPTERA: DYTISCIDAE HYDROPORINI, BIDESSINI) IN THE ARID ZONE OF AUSTRALIAEVOLUTION, Issue 12 2003Remko Leys Abstract Calcrete aquifers in arid inland Australia have recently been found to contain the world's most diverse assemblage of subterranean diving beetles (Coleoptera: Dytiscidae). In this study we test whether the adaptive shift hypothesis (ASH) or the climatic relict hypothesis (CRH) is the most likely mode of evolution for the Australian subterranean diving beetles by using a phylogeny based on two sequenced fragments of mitochondrial genes (CO1 and 16S-tRNA-ND1) and linearized using a relaxed molecular clock method. Most individual calcrete aquifers contain an assemblage of diving beetle species of distantly related lineages and/or a single pair of sister species that significantly differ in size and morphology. Evolutionary transitions from surface to subterranean life took place in a relatively small time frame between nine and four million years ago. Most of the variation in divergence times of the sympatric sister species is explained by the variation in latitude of the localities, which correlates with the onset of aridity from the north to the south and with an aridity maximum in the Early Pliocene (five mya). We conclude that individual calcrete aquifers were colonized by several distantly related diving beetle lineages. Several lines of evidence from molecular clock analyses support the CRH, indicating that all evolutionary transitions took place during the Late Miocene and Early Pliocene as a result of aridification. [source] Lebensspuren holzzerstörender Organismen an fossilen Hölzern aus dem Tertiär der Insel Lesbos, GriechenlandFOSSIL RECORD-MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE, Issue 1 2001Herbert Süss Abstract Lebensspuren (Schadbilder) holzzerstörender Organismen an fossilen Holzresten aus dem Untermiozän von Lesbos (Griechenland) werden beschrieben. Von pflanzlichen Holzzerstörern konnten Bakterien, imperfekte Pilze, Weiß- und Braunfäulepilze und in das Holz eingewachsene Wurzeln nachgewiesen werden. Von tierischen Holzzerstörern wurden Termitenfraß, durch Pflanzensauger (Homopteren) verursachtes Wundgewebe, Larvenfraß der Kambium-Minierfliege Palaeophytobia (Agromyzidae, Diptera) und Fraßgänge mit Koprolithen verschiedener Käferarten (Anobiiden?) und Milben (Acari) gefunden. Außerdem werden durch Kristallisationsvorgänge im Holz verursachte kugelförmige Gebilde beschrieben. Traces of wood destroying organisms on fossil wood from the Lower Miocene of Lesbos (Greece) are described. Among nonanimal wood destroyers evidence is presented of bacteria, Fungi imperfecti, whiterot and brownrot fungus and penetrating roots. Animal wood destroyers include termite feeding traces, wound tissues produced by plant suckers (Homoptera), larval feeding traces of the cambium miner Palaeophytobia (Agromyzidae, Diptera) and feeding channels, with coprolites, of several beetle species (Anobiidae?) and Mites (Acari). In addition globe-like structures produced in the wood through crystallization processes are described. [source] Effects of drought on contrasting insect and plant species in the UK in the mid-1990sGLOBAL ECOLOGY, Issue 1 2002M. D. Morecroft Abstract Aim We examined the effects of drought in the summer of 1995 and the subsequent year on contrasting species of plants, moths, butterflies and ground beetles. We tested whether population increases were associated with: (a) species of warm environments (b) species of dry environments (c) species with rapid reproduction (d) species with high rates of dispersal. Location The study was conducted at Environmental Change Network (ECN) sites throughout Great Britain and Northern Ireland. Methods Climate monitoring, recording of plant species in permanent plots, transect walking for butterflies, light trapping for moths and pitfall trapping for carabid beetles were used. Results There was an overall increase in the number of species recorded in permanent vegetation plots between 1994 and 1996, principally among the annual and biennial vascular plants, probably as a result of gap colonization in grasslands. Most butterfly and moth species increased between 1994 and 1995. Among the butterflies, a southern distribution and high mobility were associated with species tending to increase throughout the period 1994,96, whereas declining species tended to have a northern distribution. A similar number of carabid beetle species increased as decreased in the period 1994,96; decreasing species tended to be associated with lower temperatures and wetter soils. Conclusions Current climate change scenarios indicate that the incidence of droughts in the United Kingdom will increase. A series of dry, hot summers could lead to a rapid change in the population of some species although others, including many plants, may be more resilient. This may lead to complex changes in ecosystems and needs to be considered in planning conservation strategies. [source] The role of local and regional processes in shaping dung beetle communities in tropical forest plantations in BorneoGLOBAL ECOLOGY, Issue 4 2000Andrew J. Davis Abstract We examine whether rain forest dung beetle species found in plantations in Sabah, northern Borneo, tend to be endemic or geographically widespread. In addition, linear regressions of abundance vs. distance from a major river in primary rain forest are calculated to see if species found in plantation forest show affinity to one specific biotope (riverine vs. interior forest) in their natural habitat. Results show that 14 of the 40 species recorded from plantations are endemic to Borneo. Only edge-specialist endemic species are found in plantation forest, with no interior-forest specialists recorded. Data suggest that endemic species that are adapted to more exposed conditions in primary rain forest, such as riverine species, can in some instances tolerate man-made habitats. Twenty-nine species (±SE 4.0) per transect are recorded from plantation transects, whereas 44.2 (±1.7 SE) are recorded in primary rain forest. As species richness is much lower in plantations than natural forest, implying loss of biodiversity, we conclude that measures of biogeographic distinctiveness, whereby endemic species confer higher values, may be misleading unless they take into account edge-affinity. Local- as well as regional-distributional data may therefore be needed to interpret correctly patterns of species assemblages in derived forest ecosystems. [source] Consequences for biodiversity of reducing inputs to upland temperate pastures: effects on beetles (Coleoptera) of cessation of nitrogen fertilizer application and reductions in stocking rates of sheepGRASS & FORAGE SCIENCE, Issue 2 2004P. Dennis Abstract Current policies for upland pasture management in the UK encourage the integration of environmental objectives with livestock production through extensification of grazing systems. This study tested the hypothesis that a greater sward height in the summer would increase the diversity and abundance of grassland beetles (Coleoptera) as has been demonstrated for insects of indigenous grasslands. The hypothesis was tested with an experiment on an upland sheep pasture in mid-Wales. Experimental treatments received different nitrogen fertilizer inputs (0 or 50 kg ha,1), sheep stocking densities (12 or 9 ewes ha,1) and average sward heights in summer were constrained to 3·5 or 5·5 cm by conserving surplus grass for silage in subplots. Five treatments, replicated in three randomized blocks, combined the two stocking densities and two sward heights without nitrogen fertilizer inputs, with the fifth combining the higher stocking density, shortest sward height and the nitrogen fertilizer input. Beetles were sampled with twelve pitfall traps in each of the fifteen plots from June to September in 1993 and 1995. In years 1 (1993) and 3 (1995) of the experiment, more Coleoptera species occurred in the tall sward (an average of nine species in addition to the forty-one species present in the sward with the conventional sward height). Continuously grazed as opposed to ensiled subplots supported more beetle species but fewer individuals. Species composition of ground (Carabidae) and rove (Staphylinidae) beetles varied between treatments more than the arithmetic differences in species number. The experimental results supported the hypothesis but the benefits of taller swards to species diversity were small in the sown pastures of the study compared with indigenous upland grasslands (c. 33% fewer species). Inheritance effects of drainage, fertilizer and lime inputs, and the different species and management of cultivated pastures, may constrain the conservation benefits of altered pasture management compared with indigenous grasslands. [source] When the prairie varies: the importance of site characteristics for strategising insect conservationINSECT CONSERVATION AND DIVERSITY, Issue 4 2009CHRIS LOONEY Abstract., 1.,The bunchgrass prairies of the Palouse region in eastern Washington state and adjacent Idaho have been mostly converted to agriculture in the past century. Prairie habitat currently exists only on small remnants scattered across the landscape. 2.,The invertebrate fauna of these habitat remnants is poorly known, both in terms of species diversity and community composition. 3.,Baited pitfall traps were used to sample carrion-attracted beetles during June and July of 2003 from high-quality prairie remnants of varying size and soil characteristics. 4.,Twenty-three beetle species in five families were found. Species richness and Shannon-Wiener diversity were not significantly correlated with habitat area or perimeter,area ratio. 5.,Beetle abundance and community structure were strongly correlated with soil characteristics. Deeper, loessal soils had greater overall beetle abundance than shallower, rocky soils, although some species were more frequently captured in shallower, rocky soil sites. 6.,Conservation plans emphasising only remnant size and condition do not sufficiently capture variability in insect communities across Palouse prairie remnants. [source] Molecular phylogeny of Diabrotica beetles (Coleoptera: Chrysomelidae) inferred from analysis of combined mitochondrial and nuclear DNA sequencesINSECT MOLECULAR BIOLOGY, Issue 4 2001T. L. Clark Abstract The phylogenetic relationships of thirteen Diabrotica (representing virgifera and fucata species groups) and two outgroup Acalymma beetle species (Coleoptera: Chrysomelidae) were inferred from the phylogenetic analysis of a combined data set of 1323 bp of mitochondrial DNA (mtDNA) cytochrome oxidase subunit 1 (COI) and the entire second internal transcribed spacer region (ITS-2) of nuclear ribosomal DNA of 362 characters. Species investigated were D. adelpha, D. balteata, D. barberi, D. cristata, D. lemniscata, D. longicornis, D. porracea, D. speciosa, D. undecimpunctata howardi, D. u. undecimpunctata, D. virgifera virgifera, D. v. zeae, D. viridula, and outgroup A. blandulum and A. vittatum. Maximum parsimony (MP), minimum evolution (ME), and maximum likelihood (ML) analyses of combined COI and ITS-2 sequences clearly place species into their traditional morphological species groups with MP and ME analyses resulting in identical topologies. Results generally confer with a prior work based on allozyme data, but within the virgifera species group, D. barberi and D. longicornis strongly resolve as sister taxa as well as monophyletic with the neotropical species, D. viridula, D. cristata and D. lemniscata also resolve as sister taxa. Both relationships are not in congruence with the prior allozyme-based hypothesis. Within the fucata species group, D. speciosa and D. balteata resolve as sister taxa. Results also strongly supported the D. virgifera and D. undecimpunctata subspecies complexes. Our proposed phylogeny provides some insight into current hypotheses regarding distribution status and evolution of various life history traits for Diabrotica. [source] Short-term development of ambrosia and bark beetle assemblages following a windstorm in French broadleaved temperate forestsJOURNAL OF APPLIED ENTOMOLOGY, Issue 6 2005C. Bouget Abstract:, In most temperate deciduous forests, windstorm is the main source of dead wood. However, the effects of this natural disturbance on ambrosia and bark beetle communities are poorly known. In managed oak-hornbeam forests storm-damaged in France in 1999, we sampled ambrosia (and second bark beetles) by ethanol-baited window-flight traps in 2001. By comparing uncleared gaps, undisturbed closed-canopy controls and seedling-sapling stands, we investigated the short-term effects of gap formation, gap size and surrounding landscape to provide a snapshot of scolytid response. Contrary to expectations, neither the abundance nor the richness of ambrosia beetle species was significantly higher in gaps than in undisturbed stands. Few responses in abundance at the species level and only a slight difference in assemblage composition were detected between gaps and closed-canopy controls. Gaps were more dissimilar from seedling-sapling stands, than from closed-canopy controls. More scolytid individuals and species were caught in gaps than in seedling-sapling stands. Mean local and cumulative richness peaked in mid-size gaps. Only mid-size gaps differed from closed-canopy controls in terms of species composition. We identified generalist gap species (Xyleborus saxesenii, X. cryptographus), but also species significantly more abundant in mid-size gaps (Platypus cylindrus, Xyloterus signatus). The faunistic peculiarity of mid-size gaps seemed to be partly related to a bias in oak density among gap size classes. Few landscape effects were observed. Only the scolytids on the whole and X. dispar were slightly favoured by an increasing density in fellings at the 78 ha scale. We did not find any correlation between scolytid abundance and the surrounding closed-forest percentage area. We confirmed that temperate, deciduous, managed stands did not come under threat by ambrosia and bark beetle pests after the 1999 windstorm. Nonetheless, our data stressed the current expansion in Western Europe of two invasive species, X. peregrinus and especially X. germanus, now the predominant scolytid in the three oak forests studied. [source] Biogeographical patterns of genetic differentiation in dung beetles of the genus Trypocopris (Coleoptera, Geotrupidae) inferred from mtDNA and AFLP analysesJOURNAL OF BIOGEOGRAPHY, Issue 7 2004Loredana Carisio Abstract Aim, To examine the phylogeography and population structure of three dung beetle species of the genus Trypocopris (Coleoptera, Geotrupidae). We wanted to test whether genetic differences and genealogies among populations were in accordance with morphologically described subspecies and we aimed to establish times of divergence among subspecies to depict the appropriate temporal framework of their phylogeographical differentiation. We also wished to investigate the historical demographic events and the relative influences of gene flow and drift on the distribution of genetic variability of the different populations. Location, Europe (mostly Italy). Methods, We collected adult males from dung pats from 15 Italian localities over the period 2000,2002. For sequence analysis, some dried specimens from Albania, Croatia, Slovakia and Spain were also used. We applied cytochrome oxidase I mitochondrial DNA sequencing and the amplified fragment length polymorphism (AFLP) technique to determine whether phylogeographical patterns within the three species support the proposed hypotheses of subspecies designations, and to detect further structure among populations that might mediate diversification. Results and main conclusions, The results show a high concordance between the distribution of mtDNA variation and the main morphological groups recognized as subspecies, which thus may represent independent evolutionary units. The degree of mitochondrial divergence suggests that speciation events occurred during the Pliocene, while diversification of the main subspecific lineages took place in the Pleistocene, from c. 0.3 to 1.5 Ma. Mitochondrial and nuclear data also reveal that there is phylogeographical structuring among populations within each of the main groups and that both contemporary and historical processes determined this pattern of genetic structure. Geographical populations form monophyletic clades in both phylogenetic and network reconstructions. Despite the high levels of intrapopulational diversity, FST values indicate moderate but significant genetic differentiation among populations, and a Bayesian clustering analysis of the AFLP data clearly separates the geographical populations. Nucleotide and gene diversity estimates reveal interspecific differences in the degree of diversification among populations that may be related to the different ecological requirements of the three species. [source] Dry season ecology of riverine tiger beetles in Kruger National Park, South AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2008Jonathan R. Mawdsley Abstract The life cycles of many African species of tiger beetles (Insecta: Coleoptera: Cicindelidae) exhibit pronounced seasonality, with adult emergence and reproductive activity closely associated with seasonal rains. Anecdotal reports have suggested that adults of certain riverine tiger beetle species may be active during the dry season near perennial water sources. To test this hypothesis, fifteen sites along three perennial rivers in Kruger National Park, South Africa, were surveyed for tiger beetles in early September, 2006. Thirteen sites yielded adult beetles, with six species represented [Chaetodera regalis (Dejean), Cylindera disjuncta (Dejean), Habrodera nilotica (Dejean), Lophyra neglecta intermediola (Horn), Lophyridia fimbriata imperatrix (Srnka), and Myriochile melancholica (Fabricius)]. Microhabitat associations of adults of all six species and ovipositional/larval substrates of five of the six species are reported, along with observations on predatory and reproductive behaviours and the possible presence of an anti-predator chemical defence in C. regalis and L. fimbriata imperatrix. Résumé Le cycle vital de nombreuses espèces de Cicindèles (colépotères) africains présente une saisonnalité prononcée, l'émergence des adultes et l'activité reproductrice étant étroitement liées aux pluies saisonnières. Quelques rapports ont suggéré que les adultes de certaines espèces riveraines de cicindèles pourraient être actives en saison sèche à proximité de sources d'eau permanentes. Pour tester cette hypothèse, on a surveillé 15 sites le long de trois rivières permanentes dans le Parc National Kruger, en Afrique du Sud, au cours du mois de septembre 2006. Treize sites abritaient des cicindèles adultes, avec six espèces représentées, (Chaetodera regalis (Dejean), Cylindera disjuncta (Dejean), Habrodera nilotica (Dejean), Lophyra neglecta intermediola (Horn), Lophyridia fimbriata imperatrix (Srnka), and Myriochile melancholica (Fabricius). On a rapporté les associations d'adultes des six espèces et les substrats oviposition/larves pour cinq des six espèces dans les microhabitats, de même que des observations sur les comportements prédateur et reproducteur et sur la présence possible d'une défense chimique anti-prédateur chez C. regalis et L. fimbriata imperatrix. [source] Post-dispersal predation of Taraxacum officinale (dandelion) seedJOURNAL OF ECOLOGY, Issue 2 2005ALOIS HONEK Summary 1The importance of predation in determining the fate of post-dispersal dandelion (Taraxacum officinale) seed was investigated. Flowering, seed dispersal, seedling establishment, seed predation and seed predator abundance were recorded in 2002 and 2003, at two sites. Number of flowers were counted in 1-m2 plots, wind-borne seeds were collected in water traps, invertebrate seed predation was estimated from the rate of removal of dandelion seeds exposed on the ground and invertebrate activity density was determined by using pitfall traps. The censuses were made at 2- to 3-day intervals. 2Seed dispersal occurred 10 days after flowering. Although some seeds were blown away, 3.7,24.2 × 103 seeds m,2 fell to the ground. Four weeks after the peak in seed dispersal 0.7,3.1% of these seeds germinated. Three weeks later only 11,13% of the dispersed seed remained on the ground and most of these were damaged, the remainder presumably having been removed by predators. 3Predation of exposed seeds was low before seed dispersal but increased after its onset, in parallel with increases in the number of seeds present on the ground and in the activity density of adults of a seed-consuming carabid, Amara montivaga. 4In cafeteria experiments in which the seeds of 28 perennial and annual herbs were provided A. montivaga consumed the most dandelion seeds, followed by nine other Amara species. In no-choice experiments, under field conditions, A. montivaga consumed six seeds day,1. 5Post-dispersal predation, mainly due to aggregation of a single ground beetle species, was more important than that which occurred prior to dispersal. Although predators destroyed c. 97% of the seeds, the effect on dandelion population biology is likely to be small. 6Post-dispersal seed predation may nevertheless be important in other species, as aggregates of large invertebrate predators can consume large quantities of seed. [source] The mode of evolution of aggregation pheromones in Drosophila speciesJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2005M. R. E. SYMONDS Abstract Aggregation pheromones are used by fruit flies of the genus Drosophila to assemble on breeding substrates, where they feed, mate and oviposit communally. These pheromones consist of species-specific blends of chemicals. Here, using a phylogenetic framework, we examine how differences among species in these pheromone blends have evolved. Theoretical predictions, genetic evidence, and previous empirical analysis of bark beetle species, suggest that aggregation pheromones do not evolve gradually, but via major, saltational shifts in chemical composition. Using pheromone data for 28 species of Drosophila we show that, unlike with bark beetles, the distribution of chemical components among species is highly congruent with their phylogeny, with closely related species being more similar in their pheromone blends than are distantly related species. This pattern is also strong within the melanogaster species group, but less so within the virilis species group. Our analysis strongly suggests that the aggregation pheromones of Drosophila exhibit a gradual, not saltational, mode of evolution. We propose that these findings reflect the function of the pheromones in the ecology of Drosophila, which does not hinge on species specificity of aggregation pheromones as signals. [source] Bark beetle-mediated fungal infections of susceptible trees induce resistance to subsequent infections in a dose dependent mannerAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009Nadir Erbilgin Abstract 1,Experiments were conducted to determine whether propagule loads on the twig beetles Pityophthorus setosus and Pityophthorus carmeli (Coleoptera: Scolytidae) influence the pathogen infection of the host tree in the Monterey pine- Fusarium circinatum system. 2,On an average, F. circinatum was isolated from 2.6% and 3.3% of trapped P. setosus and P. carmeli, respectively, although the isolation percentages varied over the season, being highest in the spring and lowest in late summer and fall for both species. Mean pathogen load was 13.4 and 22.6 propagules per beetle, on P. setosus and P. carmeli, respectively, and decreased from May to November for both species. The pathogen was also isolated from approximately 55% of both beetle species that emerged from infected branches. Mean propagule load on emerged P. setosus and P. carmeli was 39 and 66.5, respectively. 3,On the basis of these data, beetle species were treated with one of three propagule loads (low, medium, high) and caged onto live branches to determine whether they could transmit the pathogen. At all propagule loads, both species transmitted the pathogen, and transmission percentage and lesion length, a measure of tree susceptibility, were positively correlated with propagule load. 4,To investigate further whether the previous transmission by beetles could affect response of the same trees to subsequent infection with F. circinatum, different branches were inoculated on the same trees used in the transmission study, and lesion lengths were measured. Lesion lengths were lower on trees that had been previously exposed to beetles treated with high or medium propagule loads than on trees that had previously been exposed to beetles treated with low propagule loads. This suggests that the initial infection by beetles carrying high or medium propagule loads induced resistance to subsequent infections of the host, whereas infections caused by beetles with low propagule loads did not. [source] Do exotic generalist predators alter host plant preference of a native willow beetle?AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2009Dong H. Cha Abstract 1,Selection can favour herbivores that choose host plants benefitting their offspring either by enhancing growth rates or by increasing larval defences against native predators. For exotic predator species that feed on herbivores, their success with invading new habitats may depend upon overcoming defences used by native prey. Whether exotic predators can alter herbivore host choice has remained unexamined. Therefore, we compared the efficacy of larval defence by Chrysomela knabi (a native beetle species) that had fed on two native willow hosts: Salix sericea (a phenolic glycoside (PG)-rich species) and Salix eriocephala (a PG-poor species), when attacked by exotic generalist predators. In addition, the preference and performance of C. knabi on S. sericea and S. eriocephala was examined. 2,Chrysomela knabi preferred and performed better on S. sericea. In a common garden, adult C. knabi were nine-fold more common and oviposited five-fold more frequently on S. sericea than on S. eriocephala. In the laboratory, adult feeding preference on leaf discs and survival rates of larvae were both greater on S. sericea, and time to pupation was shorter. 3,Chrysomela knabi larvae produced significantly more salicylaldehyde when fed S. sericea leaves than when fed S. eriocephala leaves. Additionally, those larvae with greater salicylaldehyde had reduced predation by two exotic generalist predators, Harmonia axyridis larvae and juvenile Tenodera aridifolia sinensis. 4,The results obtained in the present study suggest that selection favoured the preference of C. knabi for PG-rich willow plants because larvae grew and survived better and that selection by common exotic generalist predators would reinforce this preference. [source] Climate change and the outbreak ranges of two North American bark beetlesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2002David W. Williams Abstract 1,One expected effect of global climate change on insect populations is a shift in geographical distributions toward higher latitudes and higher elevations. Southern pine beetle Dendroctonus frontalis and mountain pine beetle Dendroctonus ponderosae undergo regional outbreaks that result in large-scale disturbances to pine forests in the south-eastern and western United States, respectively. 2,Our objective was to investigate potential range shifts under climate change of outbreak areas for both bark beetle species and the areas of occurrence of the forest types susceptible to them. 3,To project range changes, we used discriminant function models that incorporated climatic variables. Models to project bark beetle ranges employed changed forest distributions as well as changes in climatic variables. 4,Projected outbreak areas for southern pine beetle increased with higher temperatures and generally shifted northward, as did the distributions of the southern pine forests. 5,Projected outbreak areas for mountain pine beetle decreased with increasing temperature and shifted toward higher elevation. That trend was mirrored in the projected distributions of pine forests in the region of the western U.S. encompassed by the study. 6,Projected outbreak areas for the two bark beetle species and the area of occurrence of western pine forests increased with more precipitation and decreased with less precipitation, whereas the area of occurrence of southern pine forests decreased slightly with increasing precipitation. 7,Predicted shifts of outbreak ranges for both bark beetle species followed general expectations for the effects of global climate change and reflected the underlying long-term distributional shifts of their host forests. [source] Fine-scale comparative phylogeography of a sympatric sister species triplet of subterranean diving beetles from a single calcrete aquifer in Western AustraliaMOLECULAR ECOLOGY, Issue 17 2009M. T. GUZIK Abstract Calcrete aquifers in the arid Yilgarn region of central Western Australia are a biodiversity hotspot for stygofauna. A distinct pattern of interspecific size class variation among subterranean dytiscid beetle species has been observed in 29 of these aquifers where either two or three small, medium and/or large sympatric species are found that are in some cases sister species. We used a 3.5 km2 grid of bores to sample dytiscids on a fine-scale and employed a comparative phylogeographical and population genetic approach to investigate the origins of a sympatric sister species triplet of diving beetles from a single aquifer. Mitochondrial DNA sequence data from the Cytochrome oxidase c subunit I gene revealed that all three species have high levels of haplotype diversity with ancient (,1 million years ago) intra-specific coalescence of haplotypes, but low levels of nucleotide diversity. Population analyses provide evidence for multiple expansion events within each species. There was spatial heterogeneity in the distribution of genetic variation and abundance both within and among the three taxa. Population analyses revealed significant fine-scale differentiation with isolation by distance for Paroster macrosturtensis and P. mesosturtensis, but not the smallest species P. microsturtensis. Haplotype network analyses provided limited or no evidence for past population fragmentation within the large and small species, but substantial historical divergence was observed in P. mesosturtensis that was not spatially structured. A patchy population structure with contemporaneous and historical isolation by distance in the three species is likely to have been a significant isolating and diversifying force, preventing us from ruling out a potential role for allopatric divergence during speciation of this beetle sister triplet. [source] On the validity of habitat as a predictor of genetic structure in aquatic systems: a comparative study using California water beetlesMOLECULAR ECOLOGY, Issue 3 2009A. E. Z SHORT Abstract Among freshwater organisms, water flow is frequently considered to be one of the most important environmental variables affecting life-history traits such as dispersal abilities and therefore genetic structure. Recent studies have suggested that habitat type alone as defined by water flow is predictive of genetic population differentiation, while others have advocated against broad generalizations in favour of more conservative, species-specific conclusions. If aquatic habitat type is predictive of population differentiation, then one would expect sympatric taxa that occupy the same aquatic habitat to converge on a similar genetic structure. We tested this prediction by examining the haplotype diversity, phylogeographical concordance, population connectivity and population isolation of three lotic water beetle species in southern California: Anacaena signaticollis, Eubrianax edwardsii and Stictotarsus striatellus. In addition to coarse habitat and geography, we also controlled for the potentially confounding factors of range size, method of dispersal and clade independence. Together, the species spanned extremes of genetic and phylogeographical structure in all measures examined, suggesting that a coarse dichotomy of aquatic habitat type is not predictive of genetic structure. While there is little question that water flow plays a major role in shaping the life-history traits of freshwater organisms, it is perilous to confer predictive properties to an artificially simplistic dichotomy or use it as a surrogate for other unmeasured variables. [source] Size variation and mating success in the stag beetle, Lucanus cervusPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2006DEBORAH J. HARVEY Abstract The stag beetle, Lucanus cervus, is Britain's largest beetle, with a patchy distribution in southern England. The literature suggests that it displays exceptional size variation, particularly in the males, but no analysis of size inequality has ever been conducted. In the present study, stag beetle adults are measured and allometric relationships derived between various parameters and total body length. Most of the specimens found each year are fragments and head width can be used as a good predictor of total body length in each sex. Body size differs between years and between localities and male beetles show a greater degree of size inequality than females. However, L. cervus does not show greater inequality in size than many other beetle species and populations of males are composed of a relatively large number of small individuals. These males are not at a disadvantage in mating because it is the ratio of male : female size that determines mating success. Very large males are less successful in mating and it is suggested that lack of mating success may act as an additional constraint on mandible size in this species. Size variation is most likely caused by variation in larval food resources, coupled with variation in local climatic conditions. [source] Cowpea weevil flights to a point source of female sex pheromone: analyses of flight tracks at three wind speedsPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2006L. P. S. Kuenen Abstract., Two-day-old male cowpea weevils, Callosobruchus maculatus, fly upwind to a point source of female sex pheromone at three wind speeds. All beetles initiating flight along the pheromone plume make contact with the pheromone source. Analysis of digitized flight tracks indicates that C. maculatus males respond similarly to moths tested at several wind speeds. Beetles' mean net upwind speeds and speeds along their track are similar (P > 0.05) across wind speeds, whereas airspeeds increase (P < 0.01) with increasing wind speed. Beetles adjust their course angles to fly more directly upwind in higher wind speeds, whereas track angles are almost identical at each wind speed. The zigzag flight paths are generally narrow compared with most moth flight tracks and interturn distances are similar (P > 0.05) at the wind speeds employed. The frequency of these counterturns across the wind line is almost constant regardless of wind speed, and there is little variation between individuals. The upwind flight tracks are more directly upwind than those typically seen for male moths flying upwind toward sex pheromone sources. Male moths typically produce a bimodal distribution of track angles to the left and right of the windline, whereas C. maculatus males' track angles are centred about 0°. Preliminary examination of two other beetle species indicates that they fly upwind in a similar fashion. [source] | |||||||||||||||||||||||||||||||