Differences in surface-dwelling beetles of grasslands invaded and non-invaded by goldenrods (Solidago canadensis,S. gigantea) with special reference to Carabidae

We evaluated surface-dwelling Coleoptera with special reference to ground beetles (Coleoptera: Carabidae) using pitfall traps across fourteen stands of grasslands invaded and non-invaded by invasive goldenrods (Solidago canadensis L. and S. gigantea Ait.) over a 3 year period. We analysed differences in assemblages of invaded and non-invaded grasslands and tested responses of surface-dwelling beetles and carabids to invasion of goldenrods. We identified 29 Coleoptera families and 91 Carabidae species. Solidago invaded grasslands showed significantly higher activity-abundance of rove and carrion beetles and supported greater diversity and significantly higher evenness of surface-dwelling Coleoptera and the number of sampled families and individuals was higher too. We found lower taxonomic richness and significantly lower activity-abundance of carabids across goldenrods stands. Several less common Carabidae species and significantly higher representation of stenotopic brachypterous habitat specialists were also observed within invaded stands. We confirmed that differences in plant cover connected with invasion of goldenrods, soil moisture and abandonment of invaded habitats are the driving mechanisms of changes in surface-dwelling Coleoptera and ground beetles assemblages composition across Solidago invaded grasslands. Overall, changes of grassland biotopes connected with invasion of goldenrods significantly alter Coleoptera families and Carabidae assemblages, but not necessarily reduce diversity.     

Ground beetle (Coleoptera: Carabidae) assemblages in conventional and diversified crop rotation systems

Ground beetles (Coleoptera: Carabidae) are important in agro-ecosystems as generalist predators of invertebrate pests and weed seeds and as prey for larger animals. However, it is not well understood how cropping systems affect ground beetles. Over a 2-yr period, carabids were monitored two times per month using pitfall traps in a conventional chemical input, 2-yr, corn/soybean rotation system and a low input, 4-yr, corn/soybean/triticale-alfalfa/alfalfa rotation system. Carabid assemblages were largely dominated by a few species across all cropping treatments with Poecilus chalcites Say comprising >70% of pitfall catches in both years of study. Overall carabid activity density and species richness were higher in the low input, 4-yr rotation compared with the conventionally managed, 2-yr rotation. There were greater differences in the temporal activity density and species richness of carabids among crops than within corn and soybean treatments managed with different agrichemical inputs and soil disturbance regimes. Detrended correspondence analysis showed strong yearly variation in carabid assemblages in all cropping treatments. The increase in carabid activity density and species richness observed in the 4-yr crop rotation highlights the potential benefits of diverse crop habitats for carabids and the possibility for managing natural enemies by manipulating crop rotations.     

Spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds

Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding pattern of seed predation. Activity-density of carabids was measured by using pitfall traps in two organic winter wheat fields from March to July 2004. Predation of seeds (Capsella bursa-pastoris, Lamium amplexicaule, Poa annua and Stellaria media) was assessed using seed cards at the same sites and times. As measured by pitfall traps, carabids were the dominant group of insects that had access to the seed cards. In the field, predation of the four different species of seed was in the order: C. bursa-pastoris>P. annua>S. media>L. amplexicaule; and this order of preference was confirmed in the laboratory using the dominant species of carabid. On average, seed predation was higher in the field interior compared to the edge, whereas catches of carabids were highest near the edge. Weeks with elevated seed predation did not concur with high activity-density of carabids. Thus, patterns of spatial and temporal variation in seed predation were not matched by similar patterns in the abundance of granivorous carabid beetles. The lack of correspondence is ascribed to effects of confounding factors, such as weather, the background density of seeds, the composition of the carabid community, and the phenology and physiological state of the beetles. Our results show that differences in seed loss among weed species may be predicted from laboratory trials on preference. However, predator activity-density, as measured in pitfall traps, is an insufficient predictor of seed predation over time and space within a field.     

Short-term effects of mowing on insect communities in Japanese peach orchards

A population survey of insects was conducted at peach orchards in Okayama Prefecture, western Japan, every 2 weeks during May–October in 2011. Pitfall traps were used to sample more than 4000 insects at 10 orchards: 8 orchards where ground vegetation had been managed by mowing and 2 with management by herbicide application. Numbers of insect species (species richness) and numbers of insects captured in pitfall traps (trap catches) were greater after mowing. Details of the effects of mowing on insect communities were examined at four orchards that had been mowed. Results suggest that species richness and trap catches increase up to 5 days after mowing and then return to their original state. Increased species richness and trap catches were mainly attributable to the increase of ants (Formicidae) and carabids (Carabidae). These results suggest that ants and carabids actively seek prey animals that have been killed, injured, or damaged by mowing.     

The importance of epigeic beetles (Coleoptera) in tropical paddy fields: Example from Cameroon

Abstract

Indicators of diversity (population density, relative number of species, percentage of singletons, evenness) of ground beetles (Carabidae) and rove beetles (Staphylinidae) in rain-fed rice fields were assessed between 1995 and 1999 at Garoua in the Benue valley in North Cameroon. A total of 4369 individuals belonging to 44 species of carabids and 2109 staphylinids in 27 species were caught by means of pitfall traps. Among the carabids, five species: Menigius lucidus var. strigiceps Qued., Chlaeniostenus denticulatus elatus Erichson, Lissauchenius venator (Laferté), Pheropsophus marginatus Dej. and Abacetus crenulatus Dej. in decreasing order, were dominant. In the staphylinid group, the species Paederus sabaeus Erichson was the most common, followed by Stenus ravus Puthz and Stenus (mendicus) senegalensis Bernhauer. Shannon-Weiner and evenness indices varied marginally from year to year. Diversity values remained relatively low ( < 2.8) among each group of beetles, which indicated that paddy fields were moderately populated by this group of polyphagous predators. Features of predacious soil surface-dwelling beetles in West African rice ecosystems are discussed in the light of Integrated Pest Management concepts.     

Carabid patterns in olive orchards and woody semi-natural habitats: first implications for conservation biological control against <Emphasis Type="Italic">Bactrocera oleae</Emphasis>

The role of carabids (Coleoptera: Carabidae) for pest control service in perennial crop systems has been scarcely investigated. We addressed this knowledge gap exploring activity patterns and traits of adult carabids dwelling olive orchard agroecosystems as potential natural enemies of third instar larvae and pupae of Bactrocera oleae (Diptera: Tephritidae). Olive orchard supported a well-structured carabid assemblage, whose species phenologies revealed a temporal overlapping within the pest cycle. The assemblage of adjacent woody semi-natural habitats is more of conservation interest, but may play a weaker role in B. oleae control provisioning. We suggest the identification of carabids main traits for B. oleae conservation biological control as a cost-effective strategy for addressing future attention and resources only to those predators that satisfy basic requirements. This research may open new scenarios on management interventions to both conserve predators and encourage alternative approaches against olive orchards pest.     

Diversity and abundance of the coleopteran fauna from organic and conventional management systems in southern England

1 Studies of the epigeal coleopteran fauna on five pairs of organic and conventional farms were carried out between May and July 1994 in southern England using pitfall trapping. A total of 27 749 individuals and 140 species were identified. Overall, abundance of Coleoptera was greatest on organically managed farms. 2 Ground beetles (Coleoptera: Carabidae) and staphylinid beetles (Col. Staphylinidae) formed 79.7% and 16.7%, respectively, of the total catch. Pterostichus melanarius was the dominant carabid among the 45 species captured and significantly higher numbers were found in organic farms. Tachinus signatus was the most common of 44 staphylinid species, and was significantly more abundant on conventional farms. 3 For carabids, the log‐series α diversity index was higher on conventional farms but was not statistically different from that calculated for organic farms. The α index was identical for staphylinid species from organic and conventional farms. Diversity was significantly higher from conventional farms when data were combined for all of the recorded coleopteran species. 4 From this study, it appears that the main effect of farming practice is to influence the overall abundance and dominance of particular species, and the lower diversity of organic farms is a consequence of the large increase in dominance of a single species, namely P. melanarius.     

Inferring species interactions from ecological survey data: A mechanistic approach to predict quantitative food webs of seed feeding by carabid beetles

1. Ecological networks are valuable for ecosystem analysis but their use is often limited by a lack of data because many types of ecological interaction, for example, predation, are short‐lived and difficult to observe or detect. While there are different methods for inferring the presence of interactions, they have rarely been used to predict the interaction strengths that are required to construct weighted, or quantitative, ecological networks.
2. Here, we develop a trait‐based approach suitable for inferring weighted networks, that is, with varying interaction strengths. We developed the method for seed‐feeding carabid ground beetles (Coleoptera: Carabidae) although the principles can be applied to other species and types of interaction.
3. Using existing literature data from experimental seed‐feeding trials, we predicted a per‐individual interaction cost index based on carabid and seed size. This was scaled up to the population level to create inferred weighted networks using the abundance of carabids and seeds from empirical samples and energetic intake rates of carabids from the literature. From these weighted networks, we also derived a novel measure of expected predation pressure per seed type per network.
4. This method was applied to existing ecological survey data from 255 arable fields with carabid data from pitfall traps and plant seeds from seed rain traps. Analysis of these inferred networks led to testable hypotheses about how network structure and predation pressure varied among fields.
5. Inferred networks are valuable because (a) they provide null models for the structuring of food webs to test against empirical species interaction data, for example, DNA analysis of carabid gut regurgitates and (b) they allow weighted networks to be constructed whenever we can estimate interactions between species and have ecological census data available. This permits ecological network analysis even at times and in places when interactions were not directly assessed.

     

Invertebrate biodiversity affects predator fitness and hence potential to control pests in crops

Natural enemies that control pests usually allow farmers to avoid, or reduce, the use of pesticides. However, modern farming practices, that maximize yields, are resulting in loss of biodiversity, particularly prey diversity. Does this matter? Pests continue to thrive, and without alternative prey the predators should, perforce, concentrate their attentions upon the pests.We showed that a diverse diet significantly enhances predator fecundity and survival. Experiments were conducted using common generalist predators found in arable fields in Europe, the carabid beetle Pterostichus melanarius (Coleoptera: Carabidae) and the linyphiid spider Erigone atra (Araneae: Linyphiidae). We tested the hypothesis that mixed species diets were optimal, compared with restricted diets, with respect to parameters such as predator weights, egg weights, numbers of eggs laid, egg development times, egg hatching rates and predator survival. In carabids, an exclusive earthworm diet was as good as mixed diets containing earthworms for egg production and hatching, but less good than such mixed diets for increase in beetle mass and sustained egg laying. For spiders, aphids alone (Sitobion avenae) or with the Collembola Folsomia candida, drastically reduced survival. Aphids plus the Collembola Isotoma anglicana improved survival but only aphids with a mixed Collembola diet maximized numbers of hatching eggs.Predators offered only pests (slugs or aphids) had lowest growth rates and fecundity. We therefore demonstrated that conservation of a diversity of prey species within farmland, allowing predators to exploit a diverse diet, is essential if predators are to continue to thrive in crops and regulate agricultural pests.     

Importance of functional classification in the use of carabids for the environmental risk assessment of the GE crops and other agricultural practices

Carabids(Coleoptera:Carabidae)seem to be suitable bioindicalors of the environmental impacts of novel agrotechnologies,including deployment of the genetically engineered(GE)crops.In this article,we describe our effort to employ carabids in the environmental risk assessment(ERA).GE maize MON88017,its near-isogenic hybrid nontreated or treated with the soil insccticide chlorpyrifos,and two reference hybrids were used to compare three different ways how to utilize carabids in ERA.The analysis of abundance of all captured carabids or of the most abundant carabid specics did not disclose any differences between the treatments.The analysis based on the categories of functional traits revealed distinct fecatures of some treatments and proved suitable for ERA because it permitted field data transportability in spite of different species compositions.Our results indicate that GE maize has no detrimental environmental effecl,On the other hand,we found significant trends toward lower abundance and lower species number(including analysis of all carabid species together)in plots treated with the insecticide,and some tendencies to higher abundance and higher species number in plots sown with the reference hybrid PR38N86.Using functional group indicators alows identification of unintended changes in ecological functions of agroecosystem and comparability across geographics.We recommend data evaluation at the level of the categories of functional traits in ERA of GE crops and other agricultural practices.     

Earthworm communities a bioindicator of arable land management practices: A case study in semiarid region of India

The abundances and activities of earthworms in arable lands depend strongly on management practices and; therefore earthworm can act as a potential bioindicator of land use practices. In this study earthworm diversity and abundances was measured in three differently managed agro-ecosystems i.e. conventional, integrated and organic, in some sites of northern semiarid region of India. The maximal numbers of earthworm occurrence were in integrated farming system (100%, all studied sites showed the presence) followed by organically managed (70%) and conventional (18.9%) agro-ecosystems. A total of six species belonging to four different families were identified during this survey and all recorded earthworm species were present in organically managed agro-ecosystems, while integrated and conventional arable lands exhibited only three earthworm species. The abundance of earthworms in arable system was also directly related to the management practices. The values of ecological indices e.g. Shannon diversity (H′), species dominance (C), the species richness (S) and evenness (E) indicated the anthropogenic pressure on earthworm communities in arable lands of northern India.     

Transgenes sustain epigeal insect biodiversity in diversified vegetable farm systems

Many ecological studies have focused on the effects of transgenes in field crops, but few have considered multiple transgenes in diversified vegetable systems. We compared the epigeal, or soil surface-dwelling, communities of Coleoptera and Formicidae between transgenic and isoline vegetable systems consisting of sweet corn, potato, and acorn squash, with transgenic cultivars expressing Cry1(A)b, Cry3, or viral coat proteins. Vegetables were grown in replicated split plots over 2 yr with integrated pest management (IPM) standards defining insecticide use patterns. More than 77.6% of 11,925 insects from 1,512 pitfall traps were identified to species, and activity density was used to compare dominance distribution, species richness, and community composition. Measures of epigeal biodiversity were always equal in transgenic vegetables, which required fewer insecticide applications than their near isolines. There were no differences in species richness between transgenic and isoline treatments at the farm system and individual crop level. Dominance distributions were also similar between transgenic and isoline farming systems. Crop type, and not genotype, had a significant influence on Carabidae and Staphylinidae community composition in the first year, but there were no treatment effects in the second year, possibly because of homogenizing effects of crop rotations. Communities were more influenced by crop type, and possibly crop rotation, than by genotype. The heterogeneity of crops and rotations in diversified vegetable farms seems to aid in preserving epigeal biodiversity, which may be supplemented by reductions in insecticide use associated with transgenic cultivars.     

Squeezed out: the consequences of riparian zone modification for specialist invertebrates

While anthropogenic biodiversity loss in fresh waters is among the most rapid of all ecosystems, impacts on the conservation of associated riparian zones are less well documented. Riverine ecotones are particularly vulnerable to the combined ‘squeeze’ between land-use encroachment, discharge regulation and climate change. Over a 3-year period of persistent low discharge in a regulated, temperate river system (River Usk, Wales, UK; 2009–2011), specialist carabid beetles on exposed riverine sediments (ERS) were used as model organisms to test the hypotheses that catchment-scale flow modification affects riparian zone invertebrates more than local habitat character, and that this modification is accompanied by associated succession among the Carabidae. Annual summer discharge during the study period was among the lowest of the preceding 12 years, affecting carabid assemblages. The richness of specialist ERS carabids declined, while generalist carabid species’ populations either increased in abundance or remained stable. Community composition also changed, as three (Bembidion prasinum, B. decorum and B. punctulatum) of the four dominant carabids typical of ERS increased in abundance while B. atrocaeruleum decreased. Despite significant inter-annual variation in habitat quality and the encroachment of ground vegetation, beetle assemblages more closely tracked reach-scale variations between sites or catchment-scale variations through time. These data from multiple sites and years illustrate how ERS Carabidae respond to broad-scale discharge variations more than local habitat character. This implies that the maintenance of naturally variable flow regimes is at least as important to the conservation of ERS and their dependent assemblages as are site-scale measures.     

Organic versus conventional management in an apple orchard: effects of fertilization and tree-row management on ground-dwelling predaceous arthropods

1 Organic and conventional management of apple orchards may have a different effect on arthropod communities.
2 We conducted a 3-year study to assess the effect of two strategies of fertilizer treatment (organic versus chemical) and three tree-row management systems (straw mulching, tillage and herbicide) on activity-density and biodiversity of epigeic predators. Ground beetles (Carabidae), rove beetles (Staphylinidae), ants (Formicidae) and spiders (Araneae) were sampled monthly with pitfall traps in the same apple orchard during 2003, 2004 and 2005.
3 A total of 4978 individuals were collected. Carabids (56.8% of the total catches) were the most abundant taxonomic group, followed by spiders (20.7%), ants (14.8%) and rove beetles (7.7%). Tree-row management had a greater influence on predator catches than fertilizer treatment. Total predator catches were lower under the mulch. Mulching also reduced carabid abundance, but increased staphylinid catches.
4 Tree row management also had a significant effect on biodiversity parameters. Species richness did not significantly differ among treatments for ants, spiders or the total catches, but was higher on herbicide-treated plots for carabids and on mulched plots for staphylinids. Shannon–Wiener's diversity index was significantly greater in the mulched and herbicide treated plots for total predators and carabids. For staphylinids, this index was significantly greater on the mulched plots. Fertilizer application strategy only influenced the species richness of rove beetles, which was greater in the chemically-treated plots.
5 The results showed that a change from conventional to organic fertilizer treatment of apple trees may be performed without differential effects on predator activity-density or biodiversity. However, a change from herbicide treatment to mulching or mechanical weed control may be significant, depending on the taxonomic group.     

湖北潜江农田景观中步甲和蜘蛛的群落结构

1995年6～10月在湖北省潜江市郊用陷阱法研究了不同农田景观元素中步甲和蜘蛛的群落结构,结果表明：10类农田景观元素中的五类景观元素,即稻田边缘,农林间作地,不打药的滩田,少打药的旱田和植被丰富的庭院菜地分别在步甲和蜘蛛的贮存上有重要意义。1)稻田边缘步甲和蜘蛛物种的多样性指数和物种数均最高。2)农林间作地步甲和蜘蛛的均匀度居首位,多样性指数位居第二。3)不打药的滩田步甲和蜘蛛的发生数量多,步甲的主要物种为爪哇屁步甲Pheropsophus javanus和耶屁步甲.Jessoensis。蜘蛛的主要物种为星豹蛛Pardosa astrigera。4)少打药的旱田发生的步甲数量多,主要物种为大劫步甲Lesticus magnus。5)植被丰富的庭园菜地发生的蜘蛛数量多,主要蜘蛛物种为沟渠豹蛛Pardosa laura。步甲或蜘蛛物种和景观元素的对应分析表明了优势步甲大劫步甲,爪哇屁步甲,耶屁步甲和优势蜘蛛沟渠豹蛛,星豹蛛,雾豹蛛Pardosa nebulosa,拟环纹豹蛛 P.Pesudoannulata和类水狼蛛Pirata piratoides各自的适生环境,同时也表明了这些景观元 素与常规管理农田(如水稻田,商业性菜地和棉田)之间在步甲、蜘蛛物种上的联系,这为农田景观的合理设计,保证农业的持续发展提供了参考。     

A survey of ground beetles (Coleoptera: Carabidae) in Ahuriri Scenic Reserve,Banks Peninsula,and comparisons with a previous survey performed 30 years earlier

Carabidae (Coleoptera) are commonly used as indicators of ecosystem health due to their high diversity, conservation value and relative ease of identification. Carabids were monitored at Ahuriri Scenic Reserve, Port Hills, Canterbury, from August 2007 to September 2008 using pitfall traps. Carabid captures, species richness and distribution across the reserve were compared with those found in a similar study in 1977–1978. Monthly carabid captures were highly correlated with average temperature in both studies. There was little evidence of carabids responding to habitat factors, such as leaf litter depth, pH or ground cover. However, Megadromus antarcticus was positively associated with canopy openness and ground cover, whereas Holcaspis angustula was more abundant where canopy cover was extensive and there was a relatively high incidence of bare rock. Thirteen species of carabid were recorded in 1977–1978, of which six were absent, four had decreased, one was stable and two species increased in abundance from collections made in 2007–2008. The loss of one Banks Peninsula and five New Zealand endemic beetle species from this reserve is of concern, and future work should aim to gain more detailed information on the habitat requirements of these species to assist conservation management strategies.     

人工红松林步行虫(Coleoptera:Carabidae)群落物种共存格局动态分析

揭示群落物种共存格局是群落生态学研究的重点内容之一,零模型的应用极大的促进了群落物种共存格局及其调控机制的进展,然而针对地下生物群落共存格局动态特征的研究并不多见。在帽儿山森林生态站的人工红松林内,通过5次调查取样基于零模型模拟分析小尺度空间(20 m×20 m)步行虫群落物种共存格局的动态特征。结果表明:(1)共捕获步行虫20种,2278只个体,其中Carabus billergi maoershanensis为所有调查季节数量最具优势且分布最广泛的物种,步行虫群落结构具明显的时间变异性;(2)2013年6月步行虫群落为集群性共存格局,而2014年8、10月为竞争性共存格局,基于目前的零模型指标和法则难以准确揭示其他月份是集群性还是竞争性的共存格局,但所有季节的群落均表现为明显的非随机性共存格局,这些共存格局的发现并不完全支持Diamond的群落构建机制理论;(3)所有调查季节均发现很少的显著物种对,基于更严格的检验表明群落中集群性物种对多于隔离性物种对,那些表现为显著的非随机性共存关系的物种对往往是群落内数量较大且分布广泛的优势和常见物种。表明非随机性共存格局可能是帽儿山人工红松林小尺度空间步行虫群落的常见格局,这种非随机性格局具一定的短期动态稳定性,但不同季节这种非随机性共存格局类型表现不同,群落内这些较少的显著物种对可能对群落物种共存格局具有一定的贡献。     

The effect of cover plants management on soil invertebrate fauna in vineyard in Northern Italy

Cover crops are largely used in vineyard management to improve ecological services such as pest and weed control, soil protection from erosion and soil water balance. Few data are available about the effects of cover crops on soil fauna and, in particular, on important generalist predators such as Carabidae and Araneae. We compare the effects of five different cover crops treatments: Sweet Alyssum, Phacelia, Buckwheat, Faba bean and a mixture of Vetch and Oat. A three years experimental trial was developed in Northern Italy. Soil fauna was investigated using pitfall traps. Cover crops seriously affected soil fauna of most taxa. Higher abundance of predators, in particular Carabidae and Staphylinidae, was present in treatments with legumes (Faba bean and Vetch and Oat) while soil Araneae seemed not to be affected. No vineyard pests seemed to be positively affected by cover crops. We confirm the importance of cover crops in increasing soil predator abundance and consequently improving pest control.     

Long-term developments in the carabid and staphylinid (Col., CArabidae and Staphylinidae) fauna during conversion from conventional to bilogivcal farming

In two field experiments over periods of 6 and 8 years the activity density and diversity of carabids and staphylids were measured in pitfalls traps during the conversiion fron conventional to biological farming. Positive effects of the conversion were observed for many carabid species; among them Harpalus rufipes and several Amara , Bembidion and Pterostichus species, and the staphylinid fly parasitoid Aleochara bipistulata . The increased number of weed species present could at least partly explain the rise. Negative effects of the conversion were observed for several staphylinid species, among them Philonthus cognatus and Tachyporus species, and the carabid Trechus quadristriatus . It is hypothesized that the reduction in stapjylinids could partly be due to competition from the rising numbers of carabids.