Article

Predation by the carabid beetle Harpalus rufipes on the pest slug Deroceras reticulatum in the laboratory: Harpalus rufipes predation on Deroceras reticulatum

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Abstract

The Harpalini species Harpalus rufipes, as many other generalist carabids, consume a wide variety of prey and it is known to feed on pest slugs such as the grey field slug Deroceras reticulatum, but quantitative data about the predatory activity of H. rufipes on slugs are very scarce. In laboratory experiments, we assessed the capability of male H. rufipes to kill eggs and different-sized slugs of the pest species D. reticulatum in either the absence or the presence of alternative live prey (dipteran larvae and aphids). We also investigated the preference of H. rufipes for eggs and hatchlings of D. reticulatum in a choice experiment. H. rufipes killed considerable amounts of eggs and small juveniles (≤5.0 mg) of D. reticulatum, both in no-choice and in choice situations. Medium-sized juvenile slugs (10-20 mg) were seldom killed only in no-choice situations, and no large juveniles (50-60 mg) were killed. Dipteran larvae and aphids were killed also in no-choice and in choice situations. The type of alternative prey presented with slug eggs affected the survival of the eggs to H. rufipes predation. The presence of dipteran larvae as alternative prey did not affect the survival of juvenile slugs. When eggs and small juvenile slugs were offered together, the survivals of both items were similar. The obtained results under laboratory conditions suggest that the generalist predator H. rufipes might realise an important contribution to the control of pest slugs.

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... El-Danasoury et al. (2017) and El-Danasoury and Iglesias-Piñeiro (2018) reported that H. rufipes showed remarkable predation on the eggs and larvae of D. reticulatum under indoor conditions. The beetles' ability to prey on small juveniles (≤5.0 mg) was greater than their ability to prey on medium-sized juvenile slugs (10-20 mg) and large juveniles (50-60 mg) [43,44]. McKemey et al. (2001) also found that under indoor conditions P. melanarius only fed on D. reticulatum larvae (<40 mg) and eggs and rarely fed on slugs over 40 mg [39,45]. ...
... madidus (Fabricius), A. parallelepipedus, etc. [40,41,46,47]. The body size of slugs has a greater effect on the predatory abilities of their natural enemies, which may be related to the defense mechanism of slugs [43]. Hanlon et al. (2008) observed that slugs secrete large amounts of calcium to increase the mucus's viscosity to defend against natural enemies when they are exposed to damage [48,49]. ...
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Article
Terrestrial slugs are a prominent agricultural pest worldwide. To mitigate the negative effects of chemical pest control, biological control involves the use of natural enemies to reduce the impact of target pests. Numerous insects are natural predators of slugs. This study evaluated potential of the predatory species, Carabus elysii Thomson (Coleoptera: Carabidae) to biologically control the terrestrial slug, Agriolimax agrestis. Laboratory experiments were conducted to investigate the functional response, searching efficiency, and interference effect of female and male C. elysii adults regarding adult, immature, and juvenile A. agrestis individuals. The results show that both female and male ground beetle adults are functionally capable of preying on different sizes of terrestrial slugs. C. elysii exhibited Holling type II functional responses when preying on A. agrestis. The maximum daily prey consumption was 35.5 juveniles, 25.1 immatures, and 17.1 adults for adult females and 26.9 juveniles, 20.3 immatures, and 11.6 adults for adult males. The searching efficiency of female C. elysii adults regarding A. agrestis was always higher than that of male adults for identical ages and densities of A. agrestis. Moreover, the predation of C. elysii on slugs was affected by predator density. The disturbance coefficient of male C. elysii were the highest on adult A. agrestis. The results of this study suggest that female C. elysii exhibit a high potential for the biological control of A. agrestis.
... The insect family of ground beetles (Coleoptera, Carabidae) provides a range of important services in agroecosystems such as weed seed predation (Frei et al. 2019;Honek et al. 2013;Kulkarni et al. 2015;, biological control of slugs and snails (Bohan et al. 2000;El-Danasoury et al. 2017;Oberholzer and Frank 2003), and generalist predation of arthropod pests (Cividanes 2021;Williams et al. 2010;Zaller et al. 2009). Carabids also play an important role as bio-indicators, e.g., for soil attributes (Luff et al. 1989), changes in agroecosystems (Rainio and Niemelä 2003), or agricultural management (Döring and Kromp 2003). ...
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Article
Ground beetles (carabids) constitute an important functional component of biodiversity in agroecosystems, mainly because of their role as predators of pests, but also as consumers of weed seeds and as prey to other organisms. Over the past few decades, there has been a marked and continuous decline of ground beetles in Europe, and many species of this insect family are threatened by intensive agricultural practices. The effect of soil tillage, a standard technique in arable farming, on carabids has been investigated in many experimental studies. However, there is currently no clear and differentiated picture of how ground beetles are affected by tillage operations in direct and indirect ways. In this review, we narrow this gap of knowledge and show that the effects of intensive tillage on ground beetles—especially the use of mouldboard ploughing—are extremely variable. Nonetheless, on balance across multiple studies, greater tillage intensity tends to have a negative effect on abundance, species richness, and diversity. The observed variability may partly be attributed to a change in species-specific food availability or habitat conditions, induced by tillage. Tillage effects on dominant species tend to have a strong impact on total carabid abundance. The high variability of carabid responses to tillage is also a consequence of various modifying factors such as cover cropping, rotations, and variations in weed control associated with tillage. Because different modes of tillage tend to affect different carabid species, the diversification of tillage operations within a farm or region may contribute to the overall diversity of carabid communities.
... Carabids have been shown to lower grain and sugar beet aphid populations in the field, mostly by preying on aphids that have fallen off the plant during their early colonization phase (Gailis et al., 2017;Wang, 2017;Kosewska et al., 2020;Hassan, 2021). Predation on Dipteran eggs, such as those of the cabbage root fly, has been exaggerated in previous work (El-Danasoury et al., 2017;El-Danasoury and Iglesias-Piñeiro, 2018). Carabid foraging on some coleopteran pest larvae is indicated by scattered evidence (Deroulers et al., 2020;Gareau et al., 2020;Halimov, 2020;Oliveira-Hofman et al., 2020;Cividanes, 2021). ...
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Article
Ground beetles (Carabid beetles) may be found in virtually all of the world's habitats. They are one of the three most diverse families of extant beetles, with 34,275 species documented, and they serve as vital ecological markers in all environments. Edaphic living beetles catch and eat a wide variety of arthropods that live in the soil. In the case of weeds, most of the ground beetles eat their seeds and help regulate their populations. The findings of a field study in agrocenoses in SouthEast Kazakhstan from 2019 to 2020 are presented in this article. Twenty-seven ground beetle species from 9 genera were discovered as a consequence of the study. 670 soil traps yielded a total of 1012 beetles. Polytopic mesophilic beetles provide the foundation of the agrocenoses fauna. Hygrophils, mesophiles, and eurybionts are among the beetles found in irrigated areas, as are mixed and herbivorous species. The Carabidae family of beetles is the most numerous in fields and steppe settings. As a result, mixed-diet beetles can be found depending on the habitat and air temperature. The species of beetles in all fields in the investigation area are in accordance with the insects' complex. During the growth season, the diet of beetles shifts: predatory beetles take precedence initially, followed by mixed-diet beetles.
... Harpalus rufipes (Degeer, 1774) is a mixophytophage that consumes agricultural pests [47], in addition to being a pest of grain crops [48][49][50]. According to Lindroth [33], in the conditions of Scandinavian countries, the species usually occurs in cultivated lands [51], pastures, gardens, polluted areas [52][53][54], and residential areas [55][56][57][58][59]. ...
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Article
The ground beetles Zabrus tenebrioides and Harpalus rufipes (Coleoptera, Carabidae) are two of the most prevalent pests of wheat and other grasses. This article presents current data on their distribution and the results of modelling the bioclimatic ranges of these species using the maximum entropy method. To improve the model, we used various RStudio packages including the R script “thin points 4-1-18.R” package spThin and the «Raster» RStudio package. We determined the climatic parameters that promote the dispersal of the species, as well as the optimum conditions for the growth of Z. tenebrioides and H. rufipes. Maps forecasting the distribution of the studied species were generated through the perspective of two climate scenarios: RCP 2.6 and RCP 8.5. For the modelling, we utilised 435 geographic points of Z. tenebrioides occurrence and 653 points of H. rufipes occurrence. Both species have similar bioclimatic ranges, and the most favourable conditions for them are fields of grain crops. The most significant parameters influencing Z. tenebrioides are those of moisture, whereas H. rufipes is most sensitive to the temperature parameters. According to the generated climatic models for both species, a decrease in the areas of their ranges would occur in their eastern, more continental areas, with a slight shift towards the north.
... Harpalus rufipes, for example, preys on a variety of seeds but also on slugs, spiders, and insects. Moreover, prey spectrum and the degree of specialization vary across seasons (El-Danasoury, Cerecedo, Córdoba, & Iglesias-Piñeiro, 2017;Loughridge & Luff, 1983;Roubinet et al., 2018). Amara similata is known to feed on aphids, but granivory plays a vital role in its diet (Jorgensen & Toft, 1997). ...
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Article
Closely related species are often assumed to be functionally similar. Phylogenetic information is thus widely used to infer functional diversity and assembly of communities. In contrast, evolutionary processes generating functional similarity of phylogenetically distinct taxa are rarely addressed in this context. To investigate the impact of convergent evolution on functional diversity (FD) and phylogenetic diversity (PD), we reconstructed the phylogenetic structure of carabid trophic groups. We then analyzed the mandible shapes using geometric morphometrics to link specialization in functional morphology with feeding specialization among herbivores, generalist carnivores, and specialized consumers of Collembola. Our results show that carabid feeding groups are paraphyletic. Herbivory evolved at least twice and specialization to Collembola predation at least three times. Species within feeding groups share a remarkably similar mandible morphology, which evolved convergently. While specialized mandibles of herbivores and collembolan specialists represent an adaptation to their main food source, the particular mandible morphologies do not necessarily reflect the degree of food specialization within feeding groups. Only a few species with a specialized herbivorous mandible may occasionally feed on animals, but the range of specific food resources in generalist carnivore species is large, despite an almost identical mandible shape. Thus, convergent evolution in specialized feeding groups reverses the relationship between PD and functional similarity compared with generalist carnivores. We conclude that phylogenetic relationship is a poor proxy of FD in carabids. Moreover, the inconsistencies between relatedness, morphological adaptation, and ecological function require caution in the characterization of functional groups. Rather than assuming general relationships between PD and FD, we suggest integrating the analysis of evolutionary processes into functional community analyses.
... This ground beetle is one of the most frequent generalist predators in agricultural ecosystems, widely distributed over the Western Palaearctic from North-Western Africa (Holland and Luff, 2000;Kromp, 1999). It is involved in weed and pest control as a predator of seeds and invertebrates such as dipterans (Monzó et al., 2011), aphids and slugs (Birthisel et al., 2014;Brygadyrenko and Reshetniak, 2014;El-Danasoury et al., 2017;Loughridge and Luff, 1983;Macé et al., 2019), therefore it comes in close contact with contaminated soils and preys in conventionally treated croplands (Purchart and Kula, 2007). Moreover, recent studies suggested that this species is a useful bioindicator to provide early warnings of pesticide sublethal effects in the field exposure Giglio et al., 2019). ...
Article
The continuous and extensive application of agrochemicals leads to the accumulation of heavy metals (HMs) and rare earth elements (REEs) in agricultural soils and their transfer in the food web with consequent relevant risks for human and ecosystem health. In this study, HM and REE concentrations were quantified in the soil of wheat crop fields conventionally managed in the agricultural areas of Sila Mountain (Southern Italy) and compared with the concentration in a field of wild herbs, used as control. Statistical analyses and principal component analysis suggested that the use of pesticides, herbicides and fertilizers contributes to the accumulation of HMs and REEs in the soil. Different accumulation patterns were recorded in treated fields as a consequence of the type and amount of agrochemical used and the crop rotation. The exposure risk associated with the transfer through the tropic levels of agroecosystem was carried out measuring the concentration of HMs and REEs in adults of Harpalus (pseudoophonus) rufipes (De Geer, 1774) collected from each monitored site. Different accumulation patterns found in specimens from the monitored sites highlighted the ability of this generalist predator to regulate metal uptake under field conditions. The values of bioaccumulation factor (BAF) allow to defining the order of accumulation in P. rufipes which was classified as a macroconcentrator of Cd, Cu, Mg and Zn. Our results can supplement the limited information regarding the REE accumulation in soil invertebrates and may provide reference data for assessing potential environmental risks in croplands.
... Based on the current understanding of taxonomy and species interactions (Chen and Wise, 1999;Ponsard and Arditi, 2000;Scheu and Falca, 2000;Larochelle, 1990;El-Danasoury et al., 2017), invertebrates were grouped into the following categories: (1) herbivores feeding on living plant material, (2) detritivores feeding on dead plant material in the litter layer, (3) omnivores with variable diets (both animal and plant matter), and (4) predators with prey sources (Supplement 1); litter was assumed to be the basal resource of the detritusbased food web. ...
Article
To date, the field of ecological stoichiometry has focused mainly on macro-elements in aquatic systems. We investigated terrestrial systems and included micro-elements in the study to assess the elemental transfer in a detritivorous food web. We compared the food webs of six sites differing in the type and degree of metal pollution along two forest transects contaminated with copper or zinc. We measured 11 elements in the litter, herbivores, detritivores, predators and omnivores. Based on the concentrations of the elements, the differences between the trophic groups were visualized using PCA. At all the sites, the litter C:N, C:P, C:K and C:Na ratios were higher than those in the animals. The C:Cu, C:Zn and C:Ca ratios of the invertebrate trophic groups were significantly different from each other. The calculated resource:consumer N:P ratio suggests that invertebrates in the studied forests are N limited but not P limited. The presence of similar patterns at all the sites suggests that metal pollution at the studied intensity somewhat affects the transfer of elements in terrestrial macro-invertebrate food webs.
... Carabids are a diverse group of beetles that have been widely studied as biocontrol of pests such as aphids (Lang 2003;Staudacher et al. 2016;Roubinet et al. 2017), slugs (Bohan et al. 2000;Symondson et al. 2002;Thomas et al. 2009;Fusser et al. 2016;El-Danasoury et al. 2017) and Britta Frei and Yasemin Guenay: Joint first co-authorship. a variety of other pests (Sunderland 2002). ...
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Article
Carabid beetles are abundant in temperate agroecosystems and can play a pivotal role as biocontrol agents. While there is good knowledge regarding their effects on invertebrate pests in some systems, comparably little is known on the rate of seed feeding under field conditions. Molecular approaches are ideally suited for investigating carabid feeding interactions; to date, however, they have only been applied to animal prey. We sampled adult carabid beetles in organic cereal fields in three regions along a Central European transect. Regurgitates from populations of the three most common species, Poecilus cupreus, Pseudoophonus rufipes and Pterostichus melanarius, were screened for plant DNA, cereal aphids, collembolans and earthworms. The frequency of carabid individuals positive for plant DNA was high (> 70%) and independent of carabid species, sex, region and the time point of sampling. Detections for non-pest and pest prey were comparably lower, with 21.6% for collembolans, 18.1% for earthworms and 4.2% for aphids, respectively. Despite the prolonged detection period of plant DNA in carabid guts, as compared to animal prey, these first results suggest that weed seeds form an important part of the adult carabid diet. It would also lend support to the hypothesis that seed-feeding carabids are biocontrol agents of weeds, with effects of regulation on the weed seedbank that depend on behavioural and contextual factors including carabid species preferences for weed seed species, their life stage and tillage practices.
... Harpalus rufipes, for example, preys on a variety of seeds but also on slugs, spiders, and insects. Moreover, prey spectrum and the degree of specialization vary across seasons (El-Danasoury, Cerecedo, Córdoba, & Iglesias-Piñeiro, 2017;Loughridge & Luff, 1983;Roubinet et al., 2018). Amara similata is known to feed on aphids, but granivory plays a vital role in its diet (Jorgensen & Toft, 1997). ...
Article
https://authors.elsevier.com/c/1YOsG1R~eAtIg (free access until March 03, 2019). Agri-environmental schemes aim to promote biodiversity in agricultural landscapes. However, knowledge about the impact of these measures on diversity components beyond species richness, especially for non-target species and their ecological functions, is still very poor. Here, we investigated the response of ground beetle communities to the conversion of arable land into flowering fields, which are primarily installed to counteract pollinator loss in agricultural landscapes. We are focusing on the relationship between biodiversity components and the evolutionary relationship among functional groups. Land-use conversion from arable land to flowering fields has changed the phylogenetic community composition of ground beetles towards a phylogenetically clustered community. This is due to an increase in closely related medium-sized herbivorous species and a decrease in evolutionarily distinct small carnivorous species. Phylogenetic clustering did not result in a reduction of functional richness, but it increased the number of unique trait combinations of species within the local communities. This suggests a low ecological redundancy among herbivorous species. Because species richness, functional richness and phylogenetic diversity were unaffected by conversion, phylogenetic community structuring was predominantly driven by species turnover rather than by numerical changes. Flowering fields can act as refuges for herbivorous carabids that potentially affect the surrounding agricultural landscape by providing important ecosystem services such as weed control. To understand the impact of habitat transformation on carabid biodiversity, it was more informative to relate response traits to phylogenic and functional diversity than to use single diversity measures such as species richness. This conclusion might also apply to many other taxa.
... Compared to specialists, they are already present in a field at the pest's arrival and thus have the potential to prevent pest outbreaks (Chang & Kareiva, 1999;Symondson, Sunderland, et al., 2002;Wissinger, 1997). Carabids are widely recognized as important beneficial organisms in arable land, known to provide regulation services on aphids (Lang, 2003;Roubinet et al., 2017;Staudacher, Jonsson, & Traugott, 2016), pest slugs (Bohan, Bohan, Glen, Symondson, & Wiltshire, 2000;El-Danasoury, Cerecedo, Córdoba, & Iglesias-Piñeiro, 2017;Fusser, Pfister, Entling, & Schirmel, 2016;Symondson, Glen, Ives, Langdon, & Wiltshire, 2002;Thomas, Harwood, Glen, & Symondson, 2009), and weed seeds (Bohan, Boursault, Brooks, & Petit, 2011;Honek, Martinkova, & Jarosik, 2003;Tooley & Brust, 2002). According to a national-scale study, the turnover of the weed seedbank in individual fields is negatively correlated to the abundance of carabids (Bohan et al., 2011). ...
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Article
Carabids are abundant in temperate agroecosystems and play a pivotal role as biocontrol agents for weed seed and pest regulation. While there is good knowledge regarding their effects on invertebrate pests, direct evidence for seed predation in the field is missing. Molecular approaches are ideally suited to investigate these feeding interactions; however, the effects of an omnivorous diet, which is characteristic for many carabid species, and seed identity on the detection success of seed DNA has not yet been investigated. In a series of feeding experiments, seeds of six different Central European weed species were fed to beetles of the species Pseudoophonus rufipes, to determine post‐feeding seed DNA detection rates and how these are affected by plant identity, meal size, and chemical seed composition. Moreover, we investigated the effect of a mixed diet of seeds and mealworm on prey DNA detection. Four out of six seed species were detectable for up to five days after consumption, and seed species identity significantly affected post‐feeding detection rates. Detectability was negatively influenced by protein content and seed mass, whereas oil content and meal size had a positive effect. The mixed diet led to both increased detection rates and post‐feeding detection intervals of seed DNA. This suggests that mixed feeding leads to an enhancement of food detection intervals in carabid beetles and that seed identity, their chemical composition, and meal size can affect DNA detection of consumed seeds. These aspects and potential implications of this non‐invasive approach are discussed as they can become highly relevant for interpreting field‐derived data.
... Carabids are mainly ground-dwelling predators (Kromp, 1999), and a number of species predate slug eggs (Ayre, 2001;Hatteland et al., 2010;Pianezzola, Roth, & Hatteland, 2013). Harpalus rufipes (De Geer, 1774) and Poecilus cupreus (Linnaeus, 1758) are two polyphagous carabids abundant and widespread in agroecosystems of the temperate Northern Hemisphere (Kromp, 1999), which are known to destroy eggs of D. reticulatum in the laboratory (El-Danasoury, Cerecedo, Córdoba, & Iglesias-Piñeiro, 2017;. It is also known that temperature has a positive effect on the predatory activity of these and other generalist carabids when preying on live, moving prey, in the laboratory (Ayre, 2001;Frank & Bramböck, 2016;Kielty, Allen-Williams, & Underwood, 1999). ...
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Harpalus rufipes and Poecilus cupreus are two widespread polyphagous carabids which are known to destroy eggs of the pest slug Deroceras reticulatum in the laboratory. To examine the effect of temperature on the predation of the eggs of D. reticulatum by H. rufipes and P. cupreus, a laboratory experiment with different temperatures and a semi-field experiment including simulated warming were performed. In both experiments, H. rufipes killed more eggs than P. cupreus, and the predatory activity of the former increased significantly with increasing temperature. To our knowledge, this is the first study on predatory activity of polyphagous carabids on the eggs of a pest slug performed under a climate warming scenario. Results suggest that biological pest control performed by polyphagous carabids such as H. rufipes upon pest slugs may be enhanced under predicted climate warming conditions.
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Two-choice experiments on prey preferences of a generalist predator Pterostichus melanarius, and five species of slug prey, were conducted in the laboratory. Different preferences of P. melanarius for each of the slug species are described. They are interpreted as the outcome of differing slug species-specific defence mechanisms. The influence of hunger level, temperature, day/light period, condition of slugs and beetles, weight of slugs and beetles, and the sex of beetles were controlled experimentally or statistically. The order of slug species preference for predation by P. melanarius was: Deroceras reticulatum (Agriolimacidae), Malacolimax tenellus, Lehmania marginata (Limacidae), Arion distinctus and A. subfuscus (Arionidae). Efficiency of slugs’ speciesspecific defence mechanisms reflected their phylogeny. Defence mechanisms of slugs from the superfamily Arionoidea were significantly more effective at deterring an attack of non-specialised ground beetles than the defence mechanisms of slugs from Limacoidea superfamily. P. melanarius significantly preferred Agriolimacidae to Limacidae, and Limacidae to Arionidae. Slug species was the strongest factor influencing prey preferences of P. melanarius amongst slug prey. Surprisingly, this preference was much more significant than the slug weight. Weight and sex of P. melanarius had no impact on its prey preference.
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Agriculture relies on ecosystem services, such as biological control of pests, for economic success and sustainability. Commercially managed lowbush blueberries are an important crop in eastern North America, but pest control by natural enemies has not been well studied. In this paper we address questions about consumption of two blueberry pests by ground beetles (Carabidae) that are common in blueberry fields. In the first experiment, a Poecilus l. lucublandus, Carabus nemoralis, or Pterosti-chus mutus beetle was placed with two blueberry span-worm larvae, Itame argillacearia, in a simple (cup only or cup ? soil) or more complex (cup ? soil ? blueberry sprigs) treatment arena. In most cases, probability of spanworm consumption reached 100 % in simple arenas by the end of the experiment (48 h) but was 25–50 % lower in more complex arenas. In a second experiment, a male or female Pterostichus melanarius or Harpalus rufipes beetle was placed in a plastic container with saturated or dry soil into which mature blueberry maggots, Rhagoletis mendax, dropped from blueberries to pupate. Approximately 40–80 and 35 % fewer pupae were recovered when a P. mel-anarius and H. rufipes beetle was present, respectively, but soil moisture and beetle sex were not significant factors. Our results demonstrate that ground beetles can prey upon important blueberry pests, but suggest that consumption may be influenced by microhabitat structure.
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Carabid beetles were pitfall-trapped in soybean, Glycine max (L.) Merr., fields hosting populations of soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in central New York state in July and August 2004 and 2006. Carabids were collected from five fields located in three counties in 2004 and from two fields both located at the same farm in 2006. In total, adults of 60 carabid species were collected, 10 of which represent introductions from Europe. Agonum muelleri (Herbst), a Palearctic native, was the dominant carabid species both years, a role not previously reported in U.S. carabid assemblages. Both years, A. muelleri was the most abundantly trapped species, and it was collected in more than half of the pitfall traps. The majority of carabid individuals trapped, including A. muelleri, belonged to species overwintering as adults. The most common larval overwinterer, the European native Pterostichus melanarius (Illiger), made up only 6.0% (2004) and 5.5% (2006) of the total carabids species caught, yet this species was relatively broadly distributed (in 40.1% of traps in 2004 and 26.0% of traps in 2006). In three no-tillage fields with canopy closure, densities of the seven most common carabid species were high at the beginning of the season, but they decreased in early August as aphid densities began increasing. A significant negative exponential relationship described this relationship between activity density of carabids and aphid density. A no-choice feeding assay confirmed that the dominant species A. muelleri readily eats soybean aphids, which is consistent with carabid predation on soybean aphid populations. Pitfall traps were arrayed to allow comparisons of carabid beetle distributions among field edges, and distances 10 and 20 m into fields. Among the seven most common species, significantly more adults of A. muelleri, Poecilus chalcites (Say), Poecilus lucublandus (Say), and Pt. melanarius were trapped within fields compared with at field edges.
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Arion vulgaris Moquin-Tandon 1855 is one of the most important invasive species in Europe, affecting both biodiversity and agriculture. The species is spreading in many parts of Europe, inflicting severe damage to horticultural plants and cultivated crops partly due to a lack of satisfactory and effective management solutions. Molluscicides have traditionally been used to manage slug densities, although the effects are variable and some have severe side-effects on other biota. Thus, there is a need to explore potential alternatives such as biological control. The nematode Phasmarhabditis hermaphrodita is the only biological agent that has been applied commercially so far. However, other biological control agents such as carabid beetles have also been found to be promising. In addition, some carabid species have been shown to feed on A. vulgaris in the field as well as in the laboratory. Two species in particular have been found to be important predators of A. vulgaris, and these species are also common in agricultural environments: Pterostichus melanarius and Carabus nemoralis. This study is the first to use semi-field experiments in a strawberry field, manipulating densities, to investigate how P. melanarius and C. nemoralis affect densities of A. vulgaris eggs and juveniles, respectively. Gut contents of C. nemoralis were analysed using multiplex PCR methods to detect DNA of juvenile slugs. Results show that both P. melanarius and C. nemoralis significantly affect densities of slug eggs and juvenile slugs under semi-field conditions and that C. nemoralis seems to prefer slugs smaller than one gram. Carabus nemoralis seems to be especially promising in reducing densities of A. vulgaris, and future studies should investigate the potential of using this species as a biological control agent.
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Laboratory research is reported in which eggs of the pest slug Deroceras reticulatum were incubated on filter paper moistened with solutions of cupric sulphate, aluminium sulphate, ferric chloride and zinc sulphate at different concentrations. After four or more days exposure, the median lethal doses (LD50) were below 10 mu g metal ion/cm(2) for the four metals tested. Copper showed the highest toxicity with LD50 values below 5 mu g metal ion/cm(2).
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Predation on slugs, Arion lusitanicus (Mabille) and Deroceras reticulatum (Müller), and their eggs by the carabid beetles Pterostichus melanarius (Illiger) and Poecilus cupreus (L.) was investigated in the laboratory. Slugs of different size and slug eggs were offered to the beetles in petri dishes with and without several alternative prey. Pterostichus melanarius destroyed eggs of D. reticulatum and A. lusitanicus, with a clear preference for D. reticulatum eggs. The availability of some alternative prey types adversely affected feeding on D. reticulatum eggs by P. cupreus and feeding on A. lusitanicus eggs by P. melanarius. Yet consumption of D. reticulatum eggs by P. melanarius was not significantly influenced by any alternative prey. Only P. melanarius killed small D. reticulatum in the presence of alternative prey. This suggests that P. melanarius and P. cupreus may have the potential to reduce slug populations in the field by destroying slug eggs and, in the case of P. melanarius, killing freshly hatched slugs.
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Surface traps are recommended to monitor slugs in arable crops, but pastureland differs from arable land in many respects and these may affect the performance of sampling methods. Here, we report on the performance of non-baited mat refuge traps, permanently placed at the same position over more than 2 years in four established pastures, for the assessment of slug numbers and biomass, in comparison with soil sampling and flooding over 3 days. Despite the high availability of alternative shelters provided by the vegetation, a great many slugs were captured in the traps over the study period and over a wide range of temperatures recorded under the traps. The catches of slugs in traps and soil samples showed significant positive relationships in terms of numbers and biomass per sample unit and also for the mean weight of the slugs registered in each type of sample, but traps showed a bias towards the larger individuals and underestimated the numbers of smallest slugs of each species (Deroceras reticulatum, Deroceras panormitanum, Deroceras laeve and Arion intermedius). The relationships between the temperature under the traps at the time of collecting and the numbers of trapped slugs were found to be species-dependent. Besides the slugs, abundant slug eggs were regularly found beneath the traps at the four study sites, suggesting that permanent mat traps could be used to provide useful information about oviposition activity of slugs in the field.
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Harpalus rufipes (Degeer) was studied in a strawberry plot in Northumberland from 1973 to 1978 by pitfall trapping, and in the laboratory. Adults were active from April until November. Overwintered male beetles predominated at the beginning of each season until May, followed by overwintered females in June and July. Newly emerged, mainly female, beetles were active from August onwards. Overwintered females matured during early summer and laid eggs in August with a fecundity of 10–15 eggs/female. In the laboratory about 30% of beetles survived from one breeding season to the next. First- and second-instar larvae were caught in pitfall traps in autumn; in the laboratory they made approximately vertical burrows in which they stored seeds taken from the soil surface. Third-instar larvae fed on these seeds and were not active on the surface. Preferred seeds were those of grasses and Chenopodium album L. Larvae were usually aggregated in the soil at densities of 3–20/m2.
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This book, which contains 15 chapters, draws together the available information on the diversity of organisms that constitute the natural enemies of terrestrial gastropods. In a series of review chapters, it provides an authoritative synthesis of current knowledge and research for predators, parasites and pathogens. This book is for both students and professionals concerned with the conservation of gastropod communities in natural habitats and management of pestiferous species.
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This 19-chapter book discusses the biology (including reproduction, life history, feeding preferences and sexual behaviour) of molluscs as pests of horticultural, field and fodder crops, and outlines the development of appropriate mechanisms for the control of these pests (mainly biological, cultural and chemical). Two chapters review progress towards the development of chemical control strategies, one addressing the toxicology of chemicals, the other the deployment of molluscicides in baits. These chapters also highlight the statistical and biological procedures for screening and evaluating molluscicides which are not a component of the standard procedure of mollusc control. A series of chapters focus on specific crop situations, providing a synopsis of the current pest status of gastropod species or species groups.
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Myiasis is the infestation of live human and vertebrate animals with dipterous larvae, which, at least for a certain period, feed on the host’s dead or living tissue, liquid body-substances or ingested food (Zumpt, 1965). The different forms of myiasis have been classified in two ways. Firstly, in clinical terms, based upon the part of the host’s body that is infested, and secondly, in parasitological terms, according to the type of host-parasite relationship (Patton, 1922a). The first classification can provide a convenient short-cut to identification of the fly species concerned for practical diagnosis, but the second gives a better understanding of the biology of the fly as a guide to treatment or prevention as well as providing information on the evolution of the habit. A clinical classification of myiasis based on the parts of the host affected, but which also takes account of the parasite-host relationship, is given in Table 12.1.
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The calyptrate Diptera are relatively homogenous in their appearance compared to the Nematocera, being mostly robust flies with conspicuous bristles — in fact the epitome of the popular idea of flies′. The 18 000 or so described species form a natural group (′subsection′) within the higher Diptera (i.e. the infraorder Muscomorpha). Their classification is described in brief in Chapter 3.
Article
(1) The ability of Harpalus rufipes (Degeer) to feed on aphids was tested in laboratory experiments, and compared with evidence of aphid feeding on cereals and other crops in small outdoor plots. (2) In the laboratory, adult H. rufipes ate up to 130 Myzus persicae Sulz. per day. There was no apparent preference for any instar but more apterae were eaten than alatae. (3) Functional response curves were derived using both the disc equation and the random predator equation. A typical type II curve was obtained for H. rufipes. Actual feeding time on each aphid was just over one minute, and comprised about half the estimated total handling time (1.63-2.04 min). Feeding time increased when the beetle had already fed on many aphids. (4) H. rufipes was observed in the laboratory to be active on oat plants infested with Rhopalosiphum padi L. This activity increased with aphid density and males were not seen on plants at densities below fifty aphids per plant. Activity on plants also increased with temperature, with a lower threshold of below 10 ⚬C. (5) Up to 35% of H. rufipes caught weekly in the field in dry pitfall traps had fed on aphids, but the mean percentage overall was only 1.24%. The percentage which had fed on aphids increased with increasing aphid density; 34% of H. rufipes caught in a formalin-filled time-sorting trap had fed on aphids. (6) H. rufipes was swept from cereal plants at night above a threshold minimum temperature of about 6 ⚬C; 35% of swept specimens had fed on aphids. (7) It is concluded that H. rufipes has potential as an aphid predator, but the aphid density and temperature thresholds limit its usefulness at the time of year when predation would be of most benefit.
Article
This paper is the first of a series describing the effect of DDT on a population of Pieris rapae and on some of the other species inhabiting the crop. The natural mortality of Pieris has been studied to provide background information on the interrelationships of different species and the pest. Life tables have been constructed for three generations of Pieris. These show that there is a mortality of about 90% between egg and pupal stages. Over half of this mortality occurred during the first two larval instars and was primarily due to arthropod predators. Twelve species were shown, by means of the precipitin test, to have fed on Pieris. By far the most important were the ground beetle, Harpalus rufipes, and the harvestman, Phalangium opilio. As the caterpillars grew, so arthropod predation became less important. It was estimated that birds took about 20% of the larvae. Birds tended to take the larger caterpillars, so mortality due to them was only important during the last two larval stages. Four species of insect parasite attacked the caterpillars of Pieris. These were two species of Apanteles (A. rubecula and A. glomeratus) and two species of tachinid fly (Phryxe vulgaris and Epicampocera succinata). None of these contributed significantly to the total generation mortality of Pieris, although Apanteles rubecula killed about 20% of the fourth stage larvae in 1964. Two disease organisms were recorded. Of these a fungus (Metarrhizium anisophliae) had an insignificant effect, while a granulosis virus (probably Bergoldia virulenta) killed from 1% to 4% of the caterpillars. In all years a few larvae drowned during heavy rain, but the main effect of weather on the Pieris population was not on mortality but on fecundity. The number of eggs laid appears to be closely dependent on weather, and can be greatly reduced by cool, cloudy conditions.
Article
1. Interactions between the polyphagous carabid predator Pterostichus melanarius (Illiger) and slugs were investigated from July to September 1992, before and after harvesting a rape crop. The experimental site comprised a long-term field study of the effects of different forms of cultivation (ploughing vs. non-inversion tillage), and methods of straw disposal (baling vs. incorporation of chopped straw) upon invertebrate populations and crop yields. Direct-drilling was also included as a no-tillage base-line. 2. Beetles (total 2078) were collected by pitfall trapping twice weekly. Each beetle was dissected, and its crop contents weighed and tested by enzyme-linked immunosorbent assay (ELISA) to determine the concentration and quantity of slug haemolymph it contained. Slugs [Deroceras reticulatum (Muller) and Arion intermedius Normand] were extracted from soil samples by gradual flooding, to estimate both numbers and biomass. 3. Significantly more P. melanarius were trapped in direct-drilled plots than in the tilled treatments. Within the tilled treatments, greater numbers of beetles were trapped where straw was incorporated by non-inversion tillage. 4. Crop weights were significantly greater in beetles from direct-drilled plots than in those from tilled treatments, as were both the concentrations and quantities of slug haemolymph they contained. Overall, ≈84% of beetles contained slug remains. 5. Greatest concentrations and quantities of slug remains were detected prior to the disposal of rape residues at the end of July, by baling or shallow incorporation in the soil. Cultivation had both short- and long-term effects upon the proportion of the diet of the beetles that was slugs. 6. Slug biomass declined following disposal of rape residues and it was only after this time that significant treatment differences emerged. 7. Positive relationships were found between the biomass of slugs in the soil and numbers of beetles trapped, the proportion of the beetles' diet that was slugs and the quantities of slug haemolymph in beetle crops. 8. Our results strongly suggest aggregation of P. melanarius to areas of high slug biomass in the soil and preferential feeding in such areas upon slugs. As this carabid is probably the commonest large predatory beetle in arable crops in Britain, these results clearly identify P. melanarius as a potentially important slug control agent.
Article
The carabid beetle Harpalus rufipes has been examined with respect to food preference and food quality. Three different experiments were performed to clarify the role of weedy seeds and insects as food for H. rufipes: 1) adult's food preference, 2) fecundity dependent on diet, and 3) larval development dependent on diet.
Article
The carabid beetle Harpalus rufipes has been examined with respect to food preference and food quality. Three different experiments were performed to clarify the role of weedy seeds and insects as food for H. rufipes: 1) adult's food preference, 2) fecundity dependent on diet, and 3) larval development dependent on diet. No direct relation between food preference and food value was found. The seeds of Taraxacum spl were the most preferred among all the food types tested. Among the insects the cereal aphid Metopolophium dirhodum and Drosophila were highly preferred. The value of insects as a food source was much lower than the value of seeds, for the larvae as well as for the adults. Survival was identical, however, on a mixed insect diet and a mixed seed diet, but the developmental time for first and second larval instar was about twice as long on the mixed insect diet. The single species diets also differed in value. Seeds of Poa annua were of high value whereas the aphid Rhopalosiphum padi was of extremely low value.
Article
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.
Article
The effect of mucus exudation on the survival of Arion fasciatus and Deroceras reticulatum was studied by exposing mechanically stimulated and control slugs to Carabidae beetles for 24 hours. A light stimulation, lasting three minutes, exhausted the copious flow of mucus for one day. A generalist, Pterostichus niger, significantly preferred stressed D. reticulatum over control ones. Similarly, P. niger exclusively ate stressed individuals of A. fasciatus. Two beetles which specialize in gastropods, Cychrus caraboides and Carabus violaceus, consumed an equal number of stressed and control D. reticulatum and A. fasciatus. The susceptibility of the slug species to predation was different: for each beetle species, the proportion of available D. reticulatum preyed upon was significantly higher than that of A. fasciatus. The differences in the behaviour of A. fasciatus and D. reticulatum in defending themselves against attacks is described. The main reason why specialist beetles are able to hunt slugs successfully is their ability to prevent the slugs from exuding large amounts of mucus. This may succeed by different means: C. violaceus targeted their killing strokes against the posterior part of the mantle while C. caraboides hit the head of the slug. In both case the strokes seemed to paralyze the slugs.
Article
A nematode, Phasmarhabditis hermaphrodita, known to be associated with slugs but not previously thought to be parasitic, was shown to be a parasite capable of killing the pest slug Deroceras reticulatum. The parasite infects slugs in the area beneath the mantle surrounding the shell, causing a disease with characteristic symptoms, particularly swelling of the mantle. Infection leads to death of the slug, usually between seven and 21 days afterwards. The nematode then spreads and multiplies in the cadaver. In an experiment where individual D. reticulatum were exposed to different numbers of P. hermaphrodita, a significant positive relationship was found between nematode dose and slug mortality. In two experiments on host range, the nematode was found to infect and kill all pest slug species tested: Deroceras caruanae, Arion distinctus, Arion silvaticus, Arion intermedius, Arion ater, Tandonia sowerbyi and T. budapestensis, in addition to D. reticulatum.
Article
The nematode Phasmarhabditis hermaphrodita is an effective biocontrol agent for slugs. It is produced in liquid fermenters, harvested and formulated. The formulation is applied to soil as a spray or drench at a rate of 3-109 ha-1 (30 cm-2). In laboratory bioassays, it has killed all species of pest slug tested, as well as several snail species, but it was harmless to other invertebrates. In initial field trials, its use as a biocontrol agent did not threaten snails of conservation interest. It is effective in protecting plants from slug damage when it is sprayed onto moist soil at, or shortly before, the time of sowing or planting susceptible crops. When the soil surface is dry, efficacy can be improved by shallow incorporation into soil. Slugs avoid feeding or resting on areas of soil treated with nematodes, suggesting that it may be possible to target applications around individual plants or along crop rows.
Article
Laboratory studies of the food preferences of several adult carabids showed that Amara aenea DeG., Anisodactylus sanctaecrucis F., Harpalus affinis Schr., and Stenolophus comma F. were polyphagous and readily fed on the seeds of several weeds as well as on young codling moth larvae and apple maggot pupae. H. affinis also attacked 4th and 5th instar codling moth larvae and pupae more readily than the other species. Pterostichus melanarius III. showed a strong preference for the larger prey such as 5th instar codling moth larvae, earthworms, and scarabaeid larvae. The potential of these species as predators of the codling moth and the apple maggot is discussed.
Article
It could be shown, that the differences between two carabid populations on rape fields under intensive management and reduced management (50% N-input, no insecticide application) were not as striking as one might expect. Despite the fact that total individual numbers of the carabid populations, total species numbers, and number of dominant species were clearly higher in the field under reduced management, RENKONEN’s Re showed only a slight difference between the fields with nearly three-quarter correspondence in dominance structure. The presence of five more carabid species on the field under reduced management is underlined by the low values of JACCARD’s species identity and WAINSTEIN’s Kw index of similarity. On the other hand, according to SHANNON-WEAVER’s Hs for species diversity and SHANNON’s Es for evenness, the differences between the fields are minor. Even if only the dominant species were taken into account, the similarity between both fields was obvious, despite the fact that in the field under reduced management two more dominant carabid species were found. In both fields, phytophagous Amara similata was the most abundant species. Nevertheless, a special oil seed rape carabid coenosis seems to exist as well, as one was found for cereal crops and for root crops, which might consist of A. similata, Amara aenea, Harpalus affinis, Poecilus cupreus, Pseudophonus rufipes, and Pterostichus melanarius.
Data
Agriculture relies on ecosystem services, such as biological control of pests, for economic success and sustainability. Commercially managed lowbush blueberries are an important crop in eastern North America, but pest control by natural enemies has not been well studied. In this paper we address questions about consumption of two blueberry pests by ground beetles (Carabidae) that are common in blueberry fields. In the first experiment, a Poecilus l. lucublandus, Carabus nemoralis, or Pterosti-chus mutus beetle was placed with two blueberry span-worm larvae, Itame argillacearia, in a simple (cup only or cup ? soil) or more complex (cup ? soil ? blueberry sprigs) treatment arena. In most cases, probability of spanworm consumption reached 100 % in simple arenas by the end of the experiment (48 h) but was 25–50 % lower in more complex arenas. In a second experiment, a male or female Pterostichus melanarius or Harpalus rufipes beetle was placed in a plastic container with saturated or dry soil into which mature blueberry maggots, Rhagoletis mendax, dropped from blueberries to pupate. Approximately 40–80 and 35 % fewer pupae were recovered when a P. mel-anarius and H. rufipes beetle was present, respectively, but soil moisture and beetle sex were not significant factors. Our results demonstrate that ground beetles can prey upon important blueberry pests, but suggest that consumption may be influenced by microhabitat structure.
Article
The carabid predator Pterostichus melanarius (Illiger) is known to consume slugs in arable fields and may be a significant natural slug control agent. However, any quantitative study of the dynamics of this predator-prey relationship will require information on the size range of the slugs consumed. Individual P. melanarius were confined with individual slugs, Deroceras reticulatum (Mu¨ller), of different sizes (ranging form newly hatched to adults) in arenas. They readily attacked, killed and consumed slugs weighing < 40 mg. Slugs > 40 mg were killed by the beetles after prolonged exposure to attack where the slugs had no means of escape. In a second experiment, in larger laboratory arenas, P. melanarius demonstrated a strong preference for the smallest individuals, when offered a choice of slugs < 40 mg. The implications of these data are discussed with regard to optimal foraging theory and the potential impact of P. melanarius on slug populations in the field.
Article
It is the purpose of this paper to present data bearing upon the life-history of a single species of land Pulmonate, Agriolimax agrestis L., to enlarge upon certain aspects of the embryology of this species, and to demonstrate the structural and functional changes of the larva which have accompanied the transition from an aquatic to a terrestrial breeding habit.(Received March 16 1938)(Revised May 27 1938)