Mapping, characterisation, and comparison of the spatio-temporal distributions of cabbage stem flea beetle (Psylliodes chrysocephala), carabids, and Collembola in a crop of winter oilseed rape (Brassica napus)

The spatio‐temporal distribution of Psylliodes chrysocephala (L.) (Coleoptera: Chrysomelidae), a pest of oilseed rape (Brassica napus) (L.) (Cruciferae) and its potential predators, carabid beetles, within a crop of winter oilseed rape is described. The distribution of Collembola, a potential alternative food source for the predators, is also investigated. Insects were collected from spatially referenced sampling points across the crop and the counts mapped, analysed, and the degree of spatial association between the distributions determined using Spatial Analysis by Distance IndicEs (SADIE). Immigration into the crop by adult P. chrysocephala occurred from two edges and resulted in a non‐uniform distribution of the pest within the crop. Infestation of rape plants by P. chrysocephala larvae was greatest within the central area of the crop. Significant spatial association between adult female P. chrysocephala and the larval infestation of plants occurred throughout October. Three carabid species were active and abundant during peak pest immigration into the crop, viz., Trechus quadristriatus (Schrank) (Coleoptera: Carabidae), Pterostichus madidus (Fabricius) (Coleoptera: Carabidae), and Nebria brevicollis (Fabricius) (Coleoptera: Carabidae). Two of these species, T. quadristriatus and P. madidus, showed significant spatial association with the larvae of P. chrysocephala during October. All three carabid species showed a significant spatial association with Collembola during mid‐September, indicating that the latter may be an important food source for carabids during this period. In laboratory feeding experiments, only T. quadristriatus consumed the eggs of P. chrysocephala suggesting that, in the adult stage, this species may be the most important of the naturally occurring carabids as a predator of P. chrysocephala in the field. Adult T. quadristriatus may be a valuable component of an Integrated Pest Management strategy for winter oilseed rape, and the conservation of this species could be beneficial.     

Effect of predator size and temperature on the predation of Deroceras reticulatum (Muller) (Mollusca) by carabid beetles

Twenty-one carabid species were used in a laboratory study to determine the effect of beetle size and temperature on the predation of one day old Deroceras reticulatum (Muller) slugs. The beetles were caught in arable land at the study site. None of the five small-sized beetle species killed slugs, whereas five of the seven medium-sized beetle species and eight of the nine large-sized beetle species killed slugs. Four of the most abundant beetle species at the study site were used to assess the effect of temperature on the predation of 1-day-old slugs. There were significant differences in the proportion of beetles predating slugs at the different temperatures. Regression analysis showed that there was a significant increase in the proportion of Pterostichus madidus (Fabricius) and Harpalus rufipes (Degeer) beetles predating slugs as temperature increased. Nebria brevicollis (Fabricius) inflicted its highest level of slug mortality at 8°C and its larvae were the only predators to significantly increase slug mortality at 4°C, the lowest experimental temperature. Harpalus aeneus (Fabricius) inflicted significant levels of slug mortality at 20°C, the highest experimental temperature. It appeared that the predatory activity of these beetle species at the five experimental temperatures reflected their annual activity periods in the field.     

Predation on the slug Deroceras reticulatum by the carabid beetles Pterostichus madidus and Nebria brevicollis in the presence of alternative prey

1 Slugs are important pests in many agricultural crops and potential biological control agents are being studied as an alternative to molluscicides. Carabid beetles may be able to reduce slug populations, but their role as control agents may be influenced by the presence of alternative prey. 2 Attacks on the pest slug Deroceras reticulatum (Müller) by the carabid beetles Pterostichus madidus (Fabricius) and Nebria brevicollis (Fabricius) were investigated in the presence of alternative prey (earthworms and Calliphora fly larvae). Consumption of slug eggs and aphids was also investigated. 3 All five prey types were consumed to varying degrees during the experiments. Both beetle species showed a significant preference for Calliphora larvae over slugs. Pterostichus madidus showed a significant preference for earthworms over slugs. No preference was shown between earthworms or Calliphora larvae by P. madidus females or N. brevicollis. However, P. madidus males showed a significant preference for Calliphora larvae over worms. Pterostichus madidus showed no preference between slug eggs and aphids; N. brevicollis showed a significant preference for aphids over slug eggs. 4 The results from this study indicate that generalist beetles will often attack other prey in preferences to adult slugs. Slugs may not be preferred because of their mucus. Other prey items occur frequently in arable soils and generalist carabids may ignore slugs altogether and may only feed on them when slug density is high or other prey are unavailable.     

The Influence of Mucus Production by the Slug,Deroceras reticulatum,on Predation by Pterostichus madidus and Nebria brevicollis (Coleoptera: Carabidae)

Slugs are important pests in many agricultural crops and potential biological control agents are being studied as an alternative to molluscicides. Carabid beetles may be able to reduce slug populations, but the defence mucus of slugs may deter some predator attacks. Interactions between the carabids Pterostichus madidus (Fabricius) and Nebria brevicollis (Fabricius) with healthy and 'stressed' (unable to produce defence mucus) Deroceras reticulatum (Müller) were investigated in laboratory conditions. Both beetle species consumed significantly more stressed slugs than controls. Defence mucus production by control slugs hampered beetle attacks. These generalist beetle species did not direct their attacks at vulnerable parts of the prey as equal numbers of contacts were made on the slug head, mantle and tail. Blowfly ( Calliphora sp.) larvae are readily consumed by P. madidus and N. brevicollis . Calliphora larvae coated in slug defence mucus were less acceptable to both beetle species compared with control larvae. Results indicate that these generalist beetle species are unable to overcome the defence mucus production of healthy slugs. Slugs sub-lethally poisoned by molluscicides may be a more suitable prey item due to a reduction in defence mucus production.     

The abundance and reproductive activity of common Carabidae in a winter wheat crop

Abstract. 1. The number of common carabid beetles trapped-irr a wheat field on a clay with flint soil from May to October in.1971–77 differed greatly: Harpalus rufipes and Pterostichus melanarius were numerous every year; but the appearance of H.aeneus, P.madidus, Agonum dorsale, Nebria brevicollis, Notiophilus biguttatus, Bembidion lampros and Trechus quadristriatus was much more variable.
2. The numbers caught were not correlated with rainfall. Catches of the large species were positively correlated with accumulated temperature above an assumed activity threshold of 5°C, whereas the smaller beetles were negatively correlated with accumulated temperature, suggesting that the danger of desiccation at high temperatures limits their activity.
3. The egg-laying periods of the commonest species were: B.lampros and A.dorsale from late April to June; overwintered P.melanarius, H.rufipes and H.aeneus in May and June, with the summer generation of these species and of P.madidus from July to September; T.quadristriatus during August and September; N.brevicollis from September to November; N.biguttatus and C.fossor laid in the early summer and again in the autumn.
4. A few male and female H.rufipes and H.aeneus , and one female P.melanarius and N.brevicollis were each parasitized by a single tachinid larva; one P.melanarius was infested with a mermithid parasite.     

Nebria brevicollis (Fabricius, 1792) in North America,benign or malign? (Coleoptera,Carabidae, Nebriini)

Nebria brevicollis (Fabricius) is one of the most frequently encountered and widely distributed carabid beetles in Europe. Until recently, the only North American records were based on two single specimens, both from the 1930's in southeastern Canada. In 2008, this species was found at thirteen different sites in five counties in northwestern Oregon. As of the end of 2010, it has been found in thirty-four different sites in ten Oregon counties, with a north-south range of ~150 km and an east-west range of ~90 km. It was also detected in 2010 in southwestern Washington (Vancouver), just north of Portland and the Columbia River.The ecological amplitude of Nebria brevicollis in Oregon rivals that of the most eurytopic native carabid species, e.g., Pterostichus algidus LeConte and Scaphinotus marginatus (Fischer von Waldheim). It has been found in highly degraded heavy industrial sites, agricultural fields, city parks, gardens, second growth woodlands, mature conifer forests, montane rock gardens, and otherwise pristine stands of old growth noble fir, with elevations ranging from essentially sea level to 1,249 meters. Climates at these locales vary from that of the Mediterranean Willamette Valley floor, where snow rarely occurs and summers are hot and dry, to the summit of the Oregon Coast Range, where deep snow may be present from November through April and summers are cool. The carabid communities in which Nebria brevicollis has been found range from those predominantly of fellow exotic species, e.g., at heavily perturbed sites, to those where it is the only exotic species, such as at the Coast Range summit.Nebria brevicollis is clearly an invasive species in that it is not restricted to anthropogenic habitats, is rapidly expanding its North American range, and can be abundant in essentially pristine settings. What is not yet clear is whether it is or will become a damaging species. Although it is already the most abundant carabid species in some settings, based upon pitfall catches, it is unknown whether this represents competitive superiority, trap vulnerability, or utilization of previously untapped or non-limiting resources. Deleterious ecological effects could include not only competition with other predators (including other carabid species) in agricultural and natural settings but also predation upon non-adult stages of threatened and endangered species of butterflies.     

Impact of predatory carabids on below- and above-ground pests and yield in strawberry

The impact of adult carabid beetles on below- and above-ground pests and fruit yield was examined in the laboratory and a two-year strawberry field study. In the laboratory, adults of Carabus nemoralis Muller, Nebria brevicollis (F.), Pterostichus algidus LeConte, Pterostichus melanarius (Illiger), and Scaphinotus marginatus Fischer (Coleoptera: Carabidae) consumed black vine weevil, Otiorhynchus sulcatus (F.) (Coleoptera: Curculionidae) eggs, larvae and/or pupae placed on the surface. The same five carabid species showed no impact or low removal rates of O. sulcatus larvae that had burrowed into the root of potted strawberry plants. In an assay with only P. melanarius, adults consumed O. sulcatus larvae placed on the soil surface more frequently than larvae buried 1.3 or 5?cm below. In a field study, the density of adult carabids, predominantly P. melanarius, was manipulated with augmented, exclusion, and open control plots (2?×?2?m). Manipulating carabid density had no impact on the removal of sentinel O. sulcatus larvae and pupae that were buried belowground which is consistent with laboratory observations. Increasing carabid density within augmented plots led to greater removal of red clover seeds, Trifolium pratense L., placed on the soil surface in the first?year. Decreasing carabid density within exclusion plots resulted in fewer marketable fruits compared to control plots in both years. These results suggest that certain adult carabids may have limited impact belowground, and some beneficial impacts above-ground with pest control and crop protection.     

Predation by the carabid beetles Pterostichus madidus and Nebria brevicollis is affected by size and condition of the prey slug Deroceras reticulatum

1 Slugs are important pests in many agricultural crops but molluscicides commonly used to control slugs affect non‐target organisms. Encouraging biological control may help to reduce molluscicide use, but the efficiency of potential natural enemies needs to be investigated. 2 Serological tests have shown that certain carabid species consume slugs. These techniques, however, do not distinguish between scavenging and true predation, nor do they provide information on the size or other characteristics of the prey consumed. The study reported here was undertaken to establish whether scavenging of dead slugs might be an important factor contributing to positive serological test results. 3 Both Pterostichus madidus (Fabricius) and Nebria brevicollis (Fabricius) consumed Deroceras reticulatum (Müller) under laboratory conditions. Dead slugs were scavenged in preference to injured or healthy slugs. 4 Only small, live slugs (< 0.11 g) were killed by both beetle species, which may, therefore, be incapable of killing larger slugs. 5 These generalist beetle species appeared unable to overcome the defence mucus produced by slugs. The data suggest that positive serological results from field collected beetles may reflect scavenging rather than predation on live or injured slugs.     

Exploitation of host plant preferences in pest management strategies for oilseed rape (Brassica napus)

New control strategies for insect pests of arable agriculture are needed to reduce current dependence on synthetic insecticides, the use of which is unsustainable. We investigated the potential of a simple control strategy to protect spring‐sown oilseed rape, Brassica napus L. (Brassicaceae), from two major inflorescence pests: the pollen beetle, Meligethes aeneus (Fabricius) (Coleoptera: Nitidulidae), and the seed weevil, Ceutorhynchus assimilis (Paykull) (Coleoptera: Curculionidae), through exploitation of their host plant preferences. The strategy comprised, for the main crop, Starlight [an oilseed rape cultivar with relatively low proportions of alkenyl glucosinolates in the leaves (thereby releasing lower levels of attractive isothiocyanates than conventional cultivars)] and turnip rape, Brassica rapa (L.) (Brassicaceae), as a trap crop. We tested the system in laboratory, polytunnel semifield arena, and field experiments. The odours of Starlight were less attractive in olfactometer tests to both pests than those from a conventional cultivar, Canyon, and the plants were less heavily colonized in both polytunnel and field experiments. Turnip rape showed good potential as a trap crop for oilseed rape pests, particularly the pollen beetle as its odour was more attractive to both pests than that of oilseed rape. Polytunnel and field experiments showed the importance of relative growth stage in the system. As turnip rape flowers earlier than oilseed rape, beetles would be maintained on turnip rape past the damage‐susceptible growth stage of oilseed rape. The development of a pest control regime based on this strategy is discussed.     

The impact of two insecticides on predatory ground beetles (Carabidae) in newly-sown grass

Field scale experiments carried out over three years showed that chlorpyrifos reduced the numbers of several carabid beetle species caught in pitfall traps. Fonofos seed treatment was also shown to affect selected species. Consideration of the biology of individuals of groups of species provided explanations of why some species such as Nebria brevicollis, Notiophilus spp., Bembidion spp., and Trechus quadristriatus were severely affected by one or other of the chemicals, whereas other species (e.g. Amara spp., Harpalus spp.) were able to survive or recolonise pastures shortly after chemical application. Measurements of elytral and pronotal widths and counts of mature eggs in N. brevicollis, which was trapped in reduced numbers over a long period, were made and provided some information about the mode of action of these chemicals.     

Determining the host specificity of the biological control agent Trichomalus perfectus (Hymenoptera: Pteromalidae): the importance of ecological host range

We determined the host range of the parasitoid Trichomalus perfectus (Walker), a candidate for classical biological control of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), an important pest of canola in Canada. Studies were conducted in Europe and in North America. In laboratory experiments, the levels of parasitism (acceptance) of Ceutorhynchus turbatus Schultze, C. cardariae Korotyaev, C. omissus Fall and C. querceti (Gyllenhal) by T. perfectus were not significantly different than of the target host C. obstrictus. Although C. typhae (Herbst), C. pallidactylus (Marsham), C. americanus Buchanan, C. neglectus Blatchely and Ceutorhynchus sp. nr. nodipennis were parasitised by T. perfectus, the levels of parasitism were significantly lower on these species than on C. obstrictus. Ceutorhynchus peyerimhoffi Hustache, C. erysimi (Fabricius), C. alliariae H. Brisout, C. roberti Gyllenhal, Mogulones borraginis (Fabricius), Mononychus vulpeculus (Fabricius) and the leaf-mining fly Scaptomyza flava (Fallén) were not attacked. Ecological host range surveys in Europe corroborated the prediction that T. perfectus would attack C. cardariae at similar rates to C. obstrictus. In North America, the recent discovery of T. perfectus in a C. omissus population suggests that laboratory findings predicting that C. omissus is a preferred host may be the case in the field. We found that T. perfectus attacks larvae of some Ceutorhynchus spp. feeding on Brassicaceae and does not attack species outside of that host range. Thus, the parasitoid can be defined as narrowly oligophagous. These results demonstrate the value of ecological host range studies in the area of origin to validate hypotheses generated through laboratory host range experiments.     

The carabid communities on peat and upland grasslands in northern England

During a two year period 13498 individuals of 66 species of carabids were taken from 44 sites on peat and upland grasslands over an altitude range of 11-847 m in the north of England. The similarities between the carabid faunas of each site have been assessed using a modified form of the Sørensen's Index and the sites clustered according to their similarities. Five carabid communities on peat and three on mineral soils have been identified and the more abundant species have been used to characterise them. Peat Community I occurs on dry heath and is characterised by peat associated species such as Trichocellus cognatus and Bradycellus ruficollis together with widespread open habitat species such as Pterostichus madidus, Notiophilus aquaticus, Calathus melanocephalus and Nebria salina. Peat Community II is found on areas where dry heath and deep wet peat are adjacent and is characterised by the species already mentioned together with typical wet habitat species such as Pterostichus diligens, P. nigrita, Patrobus assimilis. Agonum fuliginosum. Peat Community III is found on blanket bog and is characterised by the wet habitat species in the absence of the species present on the dry heath. Peat Community IV found on the lowland oligotrophic mires is characterised by the small number of species present and the addition of Pterostichus niger and Agonum ericeti to the few wet habitat species present. Peat Community V, on the scarp slope of Dun Fell, consists of the wet habitat species of Peat Community III together with Pterostichus madidus. Nebria salina, Notiophilus aquaticus and Calathus melanocephalus. Grassland Community I, on the fell tops, is characterised by the presence of Nebria gyllenhali, Notiophilus germinyi and Patrobus assimitis. Grassland Community II and III are less clearly defined but Grassland Community II may be present on wetter sites than III and is characterised by the presence of Pterostichus nigrita, P. diligens and P. strennus together with Notiophilus biguttatus. N. aquaticus, Pterosfichus madidus and Patrobus afrorufus. Grassland Community III consists of the latter group of species together with Nebria salina, Calathus melanocephalus and Notiophilus aestuans. The number of grassland sites studied was small and there may be further communities on the upland grasslands.     

Behavioral responses of three species of ground beetle (Coleoptera: Carabidae) to olfactory cues associated with prey and habitat

The responses ofPterostichus melanarius Illiger,Harpalus rufipes DeGeer, andNebria brevicollis Fabricius (Coleoptera: Carabidae) to olfactory cues of prey and habitat were studied in a four-arm continuous-airflow olfactometer. The process was semiautomated using time-lapse image analysis by microcomputer. The primary constituent of the aphid alarm pheromone, (E)--farnesene (EBF), was synthesized and tested for a kairomonal role in prey detection by carabids. In addition, individual beetles were exposed to odors from live aphids, live collembolans, and a crude extract of wheat. All three beetle species showed evidence of olfaction.P. melanarius responded to all the odors except collembolans,H. rufipes responded to EBF and wheat, andN. brevicollis to collembolans. The use of a defence allomone as a prey-finding kairomone by certain carabid species has implications for pest management. Manipulation of predator chemical ecology by the inclusion of behavior-modifying compounds in a crop spray mix with reduced amounts of insecticide may allow for efficient aphid control with less environmental contamination.     

Prey preferences of six species of Carabidae (Coleoptera) and one Lycosidae (Araneae) commonly found in UK arable crop fields

Abstract: Laboratory experiments were used to determine the feeding preferences of six carabid beetles and one lycosid spider on aphid and collembolan prey. The first investigation used only five species of carabid Pterostichus melanarius Illiger, Pterostichus madidus F., Harpalus rufipes DeGeer, Nebria brevicollis F. and Carabus violaceus L., which had been caught most commonly in pitfall traps in the headland region of arable crop fields. When offered Brevicoryne brassicae L., Sitobion avenae F., Metopolophium dirhodum Walker and Rhopalosiphum padi L. as prey items, the species consistently consumed in high numbers was M. dirhodum . In subsequent experiments four carabids Pterostichus cupreus L., P. melanarius, P. madidus. H. rufipes and a lycosid spider Trochosa ruricola DeGeer whose distribution was shown by pitfall trapping to extend throughout the arable crop, were the chosen predators. These predators were offered a choice between M. dirhodum and entomobryid collembolans (a recognised alternative prey item) to gauge their preference between the two prey types. Both male and female P. cupreus and P. melanarius showed a significant preference for the aphid prey, while there was no significant preference displayed by the other species. The effect of temperature on the voracity of these five predators fed on M. dirhodum was investigated. There were significant differences in the number of aphids consumed by the species and sexes at the different temperatures. Regression analysis on the mean numbers of aphids eaten by each sex of the five predators, showed that in the majority of cases there was a significant increase in predation with increasing temperature. In considering the dietary preferences illustrated by these experiments, it appeared that P. cupreus and P. melanarius offered the greatest potential in controlling aphids on arable crops.     

Tracking predator density dependence and subterranean predation by carabid larvae on slugs using monoclonal antibodies

1. Subterranean carabid larvae are more numerous than surface‐active adults, yet very little is known about their ecological significance, dietary preferences or ability to regulate populations of prey species, particularly pests. Part of the reason for this is that predator–prey interactions beneath the soil are almost impossible to observe. 2. Extensive field studies have shown that adult Pterostichus melanarius (Illiger) can affect the temporal and spatial dynamics of their slug prey. However, if larvae too are feeding on slugs, this could radically affect overall predator–prey dynamics. 3. We tested the hypotheses that P. melanarius larvae would kill and consume two slug species, Deroceras reticulatum Müller and Arion intermedius Normand, under laboratory and semi‐field conditions, and that there would be no significant difference in rates of predation on these slug species. 4. A new monoclonal antibody was developed that was capable of detecting the presence of slug proteins in the guts of P. melanarius larvae. 5. Pterostichus melanarius larvae killed both A. intermedius and D. reticulatum in the laboratory, feeding to a greater extent, and growing more rapidly, on the latter. The larvae were equally effective at reducing numbers of both slug species in a crop of wheat grown in semi‐field mini plots, but predation was affected by density‐dependent intra‐specific competition amongst the beetle larvae. 6. Future modelling of the dynamic interactions between carabids and slugs will need to take into account predation by larvae.     

Ground-dwelling predators can affect within-field pest insect emergence in winter oilseed rape fields

We investigated, (i) whether the emergence from pupation of two coleopteran pest insect groups in oilseed rape (OSR, Brassica napus L.)—pollen beetles (Meligethes spp. F., Nitidulidae) and stem weevils (Ceutorhynchus pallidactylus Marsh and C. napi Gyll., Curculionidae)—is affected by the exclusion of ground-dwelling predatory arthropods, and (ii) the role for pest control of the widely abundant carabid beetles Anchomenus dorsalis Pontop. and Poecilus cupreus L. Densities of ground-dwelling arthropods were manipulated using enclosures; emerging pest adults were assessed using emergence traps. Where arthropods had been excluded, between two (June sampling) and tenfold (August sampling) more stem weevils emerged than where predators had free access. The addition of 25 adult A. dorsalis m⁻² to formerly predator-free enclosures showed similar stem weevil emergence than plots where predators had free access; the addition of 25 adult P. cupreus m⁻² did not reduce stem weevil emergence. In August, both A. dorsalis and P. cupreus additions marginally significantly reduced pollen beetle emergence. Handling editor: Patrick De Clercq.     

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.     

Consumption of carrot weevil,Listronotus oregonensis, [Coleoptera: Curculionidae] by four species of carabids on host plants in the laboratory

Four carabid species,Anisodactylus santaecrucis, Bembidion quadrimaculatum oppositum, Pterostichus lucublandus andPterostichus melanarius, abundant in carrot fields in southwestern Quebec, were tested for predation against the carrot weevil,Listronotus oregonensis, on host plants. The largest species,Pterostichus melanarius, consumed the greatest number of carrot weevil larvae and pupae.Bembidion quadrimaculatum oppositum did not prey on carrot weevil eggs laid on carrot leaves.      

Untersuchungen über das Vorkommen der Laufkäfer [Col.: Carabidae] auf Europäischen Getreidefeldern

Zusammenfassung Mit Bodenfallen wurde das Auftreten der Laufk?fer vorwiegend in Winterweizenfeldern in der Zeit von Ende Mai bis Anfang August 1973 und 1974 in Belgien, Deutschland, den Niederlanden und Schweden festgestellt. Unter den h?ufigsten Arten tratenPterostichus vulgaris undBembidion lampros in allen,Agonum dorsale in fast allen Untersuchungsgebieten gemeinsam auf. Sechzehn weitere Arten konnten als allgemein für die meisten Weizenfelder der Untersuchungsgebiete genannt werden. In fast allen Gebieten waren (gemessen an der Artenzahl) die Frühlingstiere mit Herbstbestand in der überzahl Die durchschnittliche Anazahl der pro Falle und Tag gefangenen Laufk?fer variierte von 1 bis 13 und lag im Mittel aller Gebiete bei 6 K?fern. Mit der Quadratmenthode wurden in einem norddeutschen Gebiet 6000 bis 11000 Individuen der ArtAgonum dorsale pro ha festgestellt. Es wird darauf hingewiesen, dass es lohnenswert ist, die Laufk?fer bei der Erstellung integrierter Pflanzenschutzprogramme zu berücksichtigen.

---

Summary The occurrence ofCarabidae was investigated by pitfall trapping mainly on fields of winter wheat from the end of May to the beginning of August 1973 and 1974 in Belgium, Germany, the Netherlands, and Sweden. Among the most common speciesPterostichus vulgaris andBembidion lampros were found in all,Agonum dorsale in nearly all regions. Furthermore the following 16 species could be regarded as common for most of the wheat fields in the regions of investigation:Trechus quadristriatus, T. discus, Pterostichus cupreus, P. niger, Asaphidion flavipes, Clivina fossor, Loricera pilicornis, Nebria brevicollis, Harpalus pubescens, H. aeneus, Agonum mülleri, Bembidion ustulatum, Amara familiaris, Calathus fuscipes, Carabus cancellatus ardC. granulatus. In most of the regions, if numbers of species were regarded, spring breeders with an autumn generation were more numerous than spring breedens without an autumn generation, and autumn breeders. The average number of ground beetles per pitfall trap and day varied from 1 to 13 and averaged 6, if all regions were regarded. By using the square method in a Northern German region there was stated a number of 6,000 up to 11,000 individuals ofAgonum dorsale per hectare. Where a comparison was possible, no distinct difference could be stated concerning the number of carabid species between the present investigations and those having taken place ca. 20 years ago. It is emphasized, that it is worth while taking into account the ground beetles, too, when establishing integrated control programs in cereal growing.

---

---

West-Pal?arktisch Regionale Sektion der O.I.L.B., Arbeitsgruppe Integrierte Bek?mpfung im Getreidebau

---

Dem Andenken unseres Freundes und KollegenThyge Thygesen (1923–1974) gewidmet, deran der Gründung der Arbeitsgruppe beteiligt vor Abschluss der Untersuchungen verstorben ist.     

Lasioseius Fimetorum: a soil-dwelling predator of glasshouse pests?

Female lifespan and reproduction, in terms of numberof larvae produced, of the soil-dwelling predatorymite Lasioseius fimetorum Karg (Acari:Podocinidae) fed on mould mites (Tyrophagusputrescentiae [Schrank] [Acarina: Acaridae]) wereinvestigated by laboratory experiments at 20 °C,as were the mite's consumption rates of various prey.After a preoviposition period of 10.7 days, L.fimetorum produced progeny at a daily rate of 0.7.The oviposition period lasted 23.6 days and a total of19.4 progeny were produced per female. Females livedfor 38.6 days. Eggs of the Collembola Isotomurusspp. (Collembola: Isotomidae) were consumed in thelargest amount by L. fimetorum followed by mouldmite nymphs, larvae and pupae of thrips (Frankliniella occidentalis [Pergande] [Thysanoptera:Thripidae]), eggs of the Collembola Micrisotomaspp. (Collembola: Isotomidae), Isotomurus spp.nymphs and sciarid larvae (Bradysia pauperaTuomikoski and B. tritici (Coquillet) [Diptera:Sciaridae]). Immature drain flies (Psychoda spp.[Diptera: Psychodidae]) were not consumed by L.fimetorum. The suitability of L. fimetorum forbiological control of glasshouse pests withsoil-dwelling stages is discussed in comparison withanother predatory mite Hypoaspis miles Berlese(Acarina: Hypoaspididae).