Influence of hedgerow and grassy field borders on ground beetle (Coleoptera: Carabidae) activity in fields of corn

Agricultural landscapes may be manipulated in ways that benefit predatory invertebrates by providing alternate food sources, overwintering sites, and refuge from farming activities. Ecological theory predicts that complex plant communities should support a richer community of natural enemies of pest insects than a simple plant community. A study was conducted in Iowa, USA to investigate the influence of the vegetative diversity of field boarders on the activity, species richness, and community similarities of predatory beetles occurring in corn fields.Ground beetle (Coleoptera: Carabidae) populations were compared among corn fields bounded by either complex hedges or simple grass edges. Directional pitfall traps were used to investigate activity patterns of beetles between border types and their adjacent corn fields. Beetles were trapped during four seasonal periods, based on the growth stage of corn. During corn emergence (May–June) when fields are barren, carabids were more active and species richness was higher in the corn fields bordered by woody hedges. The carabid species Scarites quadriceps, Scarites subterraneus, and Harpalus pensylvanicus, were more dominant in hedge sites as compared to grass sites at this time. Following corn–canopy closure, carabids were now more active in fields bordered by grassy edges, but beetle activity also remained high in the fields adjacent to woody hedges. Further analysis of the carabid communities by Bray–Curtis Similarity Index showed no difference among field edge types at any time of the season. Results indicate that both complex and simple field border habitats support abundant and diverse populations of carabids during most of the growing season. However, during the early growing season hedges appear to be more important than grass edges in supplying carabid beetles to corn fields. Woody hedges may serve as very important overwintering sites and as an early season refuge for predatory beetles in corn.     

Design and use of a time-sorting pitfall trap for predatory arthropods

An electronically-controlled time-sorting pitfall trap was designed which improves upon earlier models in having a 24-h rotation time, and in being capable of running continuously for at least one week without attention. Four prototypes were built, using readily available, inexpensive components, and used from June to October, 1995, to collect carabid beetles and linyphiid spiders in clover-undersown and weeded cabbages. The traps operated without malfunction during the hottest weather ever recorded in Aberdeen, when soil surface temperatures exceeded 40°C, and also during periods of torrential rain. Three spider and two carabid species dominated the catch, their nocturnal and diurnal patterns of activity being in general agreement with other published data. Some predators were apparently able to adapt to the contrasting vegetation in the two treatments, two species of Erigone spiders being nocturnal in weeded cabbages but tending to be diurnal in undersown crops.     

Impact of agricultural management on carabid communities and weed seed predation

This study evaluated the relationship between diversity and activity-density of carabid beetles and invertebrate weed seed predation in conventional, no-till, and organic management systems in the Midwest USA. Carabid beetles were sampled with pitfall traps and invertebrate seed predation rates of fall panicum and common lambsquarters were assayed with exclosure cages. Total carabid activity-density was over two times higher in the conventional systems compared to the no-till and organic management systems. In contrast, activity-densities of seed-predating carabid species were over three times higher in the no-till compared to the conventional and organic systems. Carabid diversity was higher in the no-till and organic systems compared to the conventional system, and a multivariate analysis showed that carabid community structure was distinct among the three systems. Predation of fall panicum and common lambsquarters seeds was often over two times higher in the no-till compared to the conventional and organic systems, and there was a strong correlation (r > 0.94) between seed removal rates and the total number of carabid seed predators captured in each system.     

Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera)

Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.     

Syrphids as landscape bioindicators in Italian agroecosystems

The aim of the work was to study the syrphid fauna in rural landscapes and to evaluate the quality of environment by means of the faunistic data collected. Sampling was carried out by Malaise traps and yellow sticky traps, baited with different kinds of glue. Malaise traps proved to be the most efficient monitoring system. Despite the greater efficiency, the Malaise trap failed to collect some species and in a few cases the number of species collected only by yellow trap was high. Among the three categories of landscape complexity, classified by measuring the linear development of hedgerows around the sites, the highest number of species was recorded in sites belonging to “high” complexity. In spite of this general trend, the landscape-complexity criterion showed some contradictory results, because “low” complexity habitats had higher numbers of species than “intermediate” ones. Among vegetation types, “hedgerow and abundant grass and flower strips” collected the most species. A standard method for Syrphidae, that calculates a “biodiversity maintenance function”, Syrph the Net, was used to evaluate sites.     

The influence of grassland management on ground beetles (Carabidae, Coleoptera) in Swiss montane meadows

Effects of grassland management type and intensity on carabid species richness, number of individuals and species composition were studied in the Swiss Prealps. Carabids were censused in 2001 and 2002 in 21 mown and 20 grazed meadows by means of pitfall traps.Mean species richness was significantly higher in mown plots than in grazed plots and species composition was significantly different between these two management types. Additionally, different species characteristic for mown and grazed plots were found. These results suggest that mown meadows and grazed meadows represent two habitat types for carabid beetles.Within both habitats, management intensity was quantified by fertilizing intensity, the number of cuts, cattle density and/or grazing intensity. The relationship between management intensity and the number of individuals and species was positive. Higher fertilizing intensity was the most important factor for higher species richness and had a significant influence on species composition in both habitats. Other variables positively related to the number of individuals, were the number of cuts in mown meadows and grazing intensity and altitude in grazed meadows. Additionally to fertilizing intensity, cattle density was positively related to the number of species in grazed meadows. These results illustrate that in the extensive management systems found in the Swiss Alps and Prealps, even intensively managed meadows can sustain high carabid diversity and abundance.     

Promising results from the first biological control programme against a solanaceous weed (Solanum elaeagnifolium)

Two leaf-feeding chrysomelid beetles, Leptinotarsa texana and L. defecta, have been successfully established on Solanum elaeagnifolium, a solanaceous weed inadvertently introduced into South Africa from North America during the early 1900s. Unlike L. defecta, which remains localised and scarce, L. texana has proliferated at a number of release sites. Surveys of the damage caused by L. texana on S. elaeagnifolium showed that in some situations the beetles reached densities where the host plants were completely stripped of leaves, flowers and bark, whereas fruits were not eaten by the beetles. Longer term studies in plots with and without L. texana showed that even at relatively low levels of abundance of the beetles, the growth of S. elaeagnifolium was suppressed and the capacity of the plants to produce fruits was severely curtailed. As a result L. texana has the potential to be an effective biological control agent of S. elaeagnifolium in South Africa and elsewhere.     

Fossil mesostigmatid mites (Mesostigmata: Gamasina, Microgyniina, Uropodina), associated with longhorn beetles (Coleoptera: Cerambycidae) in Baltic amber

Fossil mesostigmatid mites are extremely rare. Inclusions assignable to the tortoise mites (Mesostigmata, Uropodina) are described here for the first time from Eocene (ca. 44–49 Ma) Baltic amber. This is the oldest record of Uropodina and documents the first unequivocal amber examples potentially assignable to the extant genus Uroobovella Berlese, 1903 (Uropodoidea: Urodinychidae). Further mites in the same amber pieces are tentatively assigned to Microgynioidea (Microgyniina) and Ascidae (Gamasina), both potentially representing the oldest records of their respective superfamily and family groups. This new material also preserves behavioural ecology in the form of phoretic deutonymphs attached to their carriers via a characteristic anal pedicel. These deutonymphs in amber are intimately associated with longhorn beetles (Coleoptera: Cerambycidae), probably belonging to the extinct species Nothorhina granulicollis Zang, 1905. Modern uropodines have been recorded phoretic on species belonging to several beetle families, including records of living Uroobovella spp. occurring on longhorn beetles. Through these amber inclusions, a uropodine–cerambycid association can now be dated back to at least the Eocene.     

Localization and density of phoretic deutonymphs of the mite Uropoda orbicularis (Parasitiformes: Mesostigmata) on Aphodius beetles (Aphodiidae) affect pedicel length

The phoretic stage of Uropodina mites is a deutonymph with developed morphological adaptations for dispersal by insects. Phoretic deutonymphs are able to produce a pedicel, a stalk-like temporary attachment structure that connects the mite with the carrier. The aim of our study was to determine whether localization and density of phoretic deutonymphs on the carrier affect pedicel length. The study was conducted on a common phoretic mite—Uropoda orbicularis (Uropodina) and two aphodiid beetles—Aphodius prodromus and Aphodius distinctus. Our results show that pedicel length is influenced by the localization of deutonymphs on the body of the carrier. The longest pedicels are produced by deutonymphs attached to the upper part of elytra, whereas deutonymphs attached to femora and trochanters of the third pair of legs and the apex of elytra construct the shortest pedicels. In general, deutonymphs attached to more exposed parts of the carrier produce longer pedicels, whereas shorter pedicels are produced when deutonymphs are fixed to non-exposed parts of the carrier. A second factor influencing pedicel length is the density of attached deutonymphs. Mean pedicel length and deutonymph densities were highly correlated: higher deutonymph density leads to the formation of longer pedicels. The cause for this correlation is discussed, and we conclude that pedicel length variability can increase successful dispersal.     

Skimming behaviour and spreading potential of Stenus species and Dianous coerulescens (Coleoptera: Staphylinidae)

Rove beetles of the genus Stenus Latreille and the genus Dianous Leach possess pygidial glands containing a multifunctional secretion of piperidine and pyridine-derived alkaloids as well as several terpenes. One important character of this secretion is the spreading potential of its different compounds, stenusine, norstenusine, 3-(2-methyl-1-butenyl)pyridine, cicindeloine, α-pinene, 1,8-cineole and 6-methyl-5-heptene-2-one. The individual secretion composition enables the beetles to skim rapidly and far over the water surface, even when just a small amount of secretion is emitted. Ethological investigations of several Stenus species revealed that the skimming ability, skimming velocity and the skimming behaviour differ between the Stenus species. These differences can be linked to varied habitat claims and secretion saving mechanisms. By means of tensiometer measurements using the pendant drop method, the spreading pressure of all secretion constituents as well as some naturally identical beetle secretions on the water surface could be established. The compound 3-(2-methyl-1-butenyl)pyridine excelled stenusine believed to date to be mainly responsible for skimming relating to its surface activity. The naturally identical secretions are not subject to synergistic effects of the single compounds concerning the spreading potential. Furthermore, evolutionary aspects of the Steninae’s pygidial gland secretion are discussed.     

Fragmented habitats of traditional fruit orchards are important for dead wood-dependent beetles associated with open canopy deciduous woodlands

The conservation of traditional fruit orchards might be considered to be a fashion, and many people might find it difficult to accept that these artificial habitats can be significant for overall biodiversity. The main aim of this study was to identify possible roles of traditional fruit orchards for dead wood-dependent (saproxylic) beetles. The study was performed in the Central European landscape in the Czech Republic, which was historically covered by lowland sparse deciduous woodlands. Window traps were used to catch saproxylic beetles in 25 traditional fruit orchards. The species richness, as one of the best indicators of biodiversity, was positively driven by very high canopy openness and the rising proportion of deciduous woodlands in the matrix of the surrounding landscape. Due to the disappearance of natural and semi-natural habitats (i.e., sparse deciduous woodlands) of saproxylic beetles, orchards might complement the functions of suitable habitat fragments as the last biotic islands in the matrix of the cultural Central European landscape.     

Delayed colonisation of arable fields by spring breeding ground beetles (Coleoptera: Carabidae) in landscapes with a high availability of hibernation sites

The colonisation of winter barley fields by spring breeding carabids and its temporal modulation by the amount of potential hibernation sites was studied. Species richness of carabids was lower in landscapes with high length of boundaries and a high amount of non-cropped open habitats during early stages of the beetles’ colonisation of arable fields. Species number of beetles with high dispersal potential responded to this landscape features at coarse spatial scales whereas beetles with low dispersal potential responded to intermediate scales. However, the negative impact of potential hibernation sites on colonisation diminished in later sampling phases. The patterns observed may be explained by both overwintering in arable soils in less complex landscapes and delayed colonisation in more complex landscapes. The seasonal patterns of landscape control suggest a need to account for temporal dynamics in interactions between species or functional groups and landscape properties. A high temporal resolution is needed in studies that focus on ecosystem function and services in agricultural landscapes, as direction of effect (positive/negative) of management on animal communities may change across spatial scales and within short time periods.     

Methyl 2-(methylthio)benzoate: the unique sulfur-containing sex pheromone of<Emphasis Type="Italic"> Phyllophaga crinita</Emphasis>

The female-produced sex pheromone of Phyllophaga crinita (Burmeister) (Coleoptera: Scarabaeidae: Melolonthinae; the adult has no common name) is identified as methyl 2-(methylthio)benzoate. This is the first identification of a sulfur-containing, long-distance, female-produced sex attractant from any insect taxa. The root-feeding larvae of this species are serious pests in many crops in Texas and Mexico. In field tests, many P. crinita males were captured in traps baited with the authentic compound. Interestingly, a heteroatom analog, methyl 2-methoxybenzoate, also captured P. crinita males, but only at a dose 10,000 times higher than the lowest tested dose of the authentic pheromone.In memory of M.G. Villani, who died on 15 May 2001. His enthusiasm for soil-dwelling scarab beetles and contributions to their research are greatly missed.     

湖底陷阱捕获内污染技术在浅水湖泊的应用

基于研发的湖底陷阱捕获内污染技术,在巢湖进行应用研究.结果表明,湖底陷阱可有效收集叶绿素a、有机质、总氮和总磷等湖底沉积物中内源污染物.不同位置和季节湖底陷阱收集的沉积物厚度差异显著,西巢湖收集的污染物含量最多,湖心区域收集污染物量最少;夏秋季节淤积较快,冬春季节淤积略慢.单位面积（1m²）湖底陷阱年收集叶绿素a、有机质、总氮和总磷可分别达2.37~15.28g、8.96~21.82kg、0.78~1.88kg和0.30~0.93kg.综合考虑湖流场、风浪场、湖底污染物分布及厚度,巢湖湖体内沿湖流汇集区可布置6条11~33km的湖底陷阱,并在7个主要入河口布置湖底陷阱,同时可利用现有航道,进一步加深后形成湖底陷阱,可为巢湖内源控制提供新的治理手段和管理方法.     

Potential feeding deterrents found in hemlock woolly adelgid, Adelges tsugae

The nonnative hemlock woolly adelgid (Adelges tsugae Annand, Hemiptera: Sternorrhyncha: Adelgidae) has been a significant mortality agent of eastern hemlock (Tsuga canadensis Carriere) throughout a large portion of its geographic range. During a study investigating adelgid vigor in relation to host health, it was noted that adelgid extracts ranged from a yellow to a deep red color. Analysis by GC–MS identified the presence of the anthraquinone, chrysophanol and its anthrone precursor, chrysarobin in the extract. These compounds are predator deterrents in several other insects, including chrysomelid beetles. It is hypothesized that these compounds serve a similar purpose in the hemlock woolly adelgid.     

The oldest micropepline beetle from Cretaceous Burmese amber and its phylogenetic implications (Coleoptera: Staphylinidae)

The staphylinid subfamily Micropeplinae includes small strongly sclerotized beetles with truncate elytra leaving the most part of abdomen exposed. Fossil micropeplines are rare and confined to Cenozoic representatives of extant genera. Here, we describe the oldest micropepline, Protopeplus cretaceus gen. and sp. n., from the Upper Cretaceous Burmese amber. Fluorescence microscope and confocal laser scanning microscopy (CLSM) were both used to reveal diagnostic features of Micropeplinae and some primitive traits that place Protopeplus very basally within Micropeplinae.     

Long-term changes of farmland game populations in a post-socialist country (Hungary)

Agricultural intensification presents a major threat to European biodiversity. This generalisation is largely based on studies from western and northern Europe. Here it is shown that the development of agriculture in a post-socialist country (Hungary) was marked by sudden changes, e.g., a 10-fold increase of fertiliser consumption in the late 1960s as a result of decision-making in the socialist command economic structures, and similar decreases after the collapse of socialism in the 1990s. Hungarian populations of two characteristic farmland species, the brown hare (Lepus europaeus) and grey partridge (Perdix perdix) are analysed and their collapse over the past four decades is related to agricultural data on production from FAO statistics. This decline was found to be negatively correlated with most measures of agricultural intensification (cereal and milk yields, number of machinery), and positively with cattle density. Multiple regression analyses of intensification measures indicated a similar pattern, although cattle density was not included into the models. Interestingly, farmland diversity in the models was negative predictor of population sizes. The sudden changes in agriculture were not indicated in the population trends of the two species. Probably, the relationship between agricultural intensification and small game species decline may not be as simple as correlation analyses indicated.     

Sex pheromone chemistry and field trapping studies of the elm spanworm Ennomos subsignaria (Hübner) (Lepidoptera:Geometridae)

The elm spanworm, Ennomos subsignaria (Hübner), occurs throughout Canada and the eastern United States and can be a destructive forest pest on a wide range of deciduous trees. Gas chromatography/mass spectrometry (GC/MS) and coupled gas chromatographic–electroantennographic detection (GC/EAD) analysis of pheromone gland extracts, in combination with chemical synthesis and field trapping studies have identified (2S, 3R)-2-((Z)-oct-2′-enyl)-3-nonyl oxirane (hereafter Z6-9S, 10R-epoxy-19:H) as the female-produced sex pheromone. Significantly more male moths were captured between 1–100 μg loadings of this compound on red rubber septa in sticky traps compared to blank (unbaited) traps; catches then declined at higher dosages (500–1000 μg). The other isomeric enantiomer, (2R, 3S)-2-[(Z)-oct-2′-enyl]-3-nonyl oxirane (Z6-9R, 10S-epoxy-19:H), at a 10-μg dosage did not elicit trap capture. The likely precursor to the active epoxide, (Z, Z)-6, 9-nonadecadiene ((Z, Z)-6, 9-19:H), identified in virgin female sex pheromone glands, did not elicit trap capture either, and inhibited trap capture when combined with the active epoxide. Racemic 2-((Z)-oct-2′-enyl)-3-nonyl oxirane showed no significant difference in trap capture compared with Z6-9S, 10R-epoxy-19:H, indicating that the opposite enantiomer was not antagonistic. The addition of the EAD-active diene epoxide enantiomers (2S, 3R)-2-[(Z, Z)-octa-2′, 5′-dienyl]-3-nonyl oxirane or (2R, 3S)-2-[(Z, Z)-octa-2′, 5′-dienyl]-3-nonyl oxirane in admixture with Z6-9S, 10R-epoxy-19:H (at 10% of the latter) did not enhance or decrease trap capture compared to Z6-9S, 10R-epoxy-19:H oxirane alone, so they are not likely pheromone components. This pheromone, impregnated in rubber septa at less than 100-μg dosage, can now be used as a trap bait to develop detection and monitoring strategies for this insect.     

Discovery of mycangia and the associated xylose-fermenting yeasts in stag beetles (Coleoptera: Lucanidae)

Most wood-feeding insects need an association with microbes to utilize wood as food, and some have special organs to store and convey the microbes. We report here the discovery of the microbe-storage organ (mycangium) in stag beetles (Coleoptera: Lucanidae), which develop in decayed wood. The mycangium, which was discovered in the abdomen, is present in all adult females of 22 lucanid species examined in this study, but absent in adult males. By contrast, adult insects of both sexes of selected Passalidae, Geotrupidae, and Scarabaeidae, which are related to Lucanidae, lacked mycangia similar to those of the lucanid species. Yeast-like microbes were isolated from the mycangium of five lucanid species. DNA sequence analyses indicate that the microbes are closely related to the xylose-fermenting yeasts Pichia stipitis, Pichia segobiensis, or Pichia sp. known from the gut of a passalid species.     

Chirality determines pheromone activity for flour beetles

Olfactory perception and orientation behaviour of female and male flour beetles (Tribolium castaneum, T. confusum) to single stereoisomers of their aggregation pheromone revealed maximal receptor potentials and optimal attraction in response to 4R,8R-(?)-dimethyldecanal, whereas its optical antipode 4S,8S-(+)-dimethyldecanal was found to be inactive in this respect. Female flour beetles of both species were ≈ 10³ times less attracted to 4R,8S-(+)- and 4S,8R-(?)-dimethyldecanal than to 4R,8R-(?)-dimethyldecanal, while male flour beetles failed to respond to the R,S-(+)- and S,R-(?)-stereoisomers. Pheromone extracts of prothoracic femora from unmated male flour beetles elicited higher receptor potentials in the antennae of females than in those of males. The results suggest that the aggregation pheromone emitted by maleT. castaneum as well as maleT. confusum has the stereochemical structure of 4R,8R-(?)-dimethyl-decanal, which acts as sex attractant for the females and as aggregant for the males of both species.