共查询到16条相似文献，搜索用时 15 毫秒
1.
Marco Ferrante Gabor L. Lovei Serena Magagnoli Lenka Minarcikova Elena Larisa Tomescu Giovanni Burgio Ludovit Cagan Mihael Cristin Ichim 《Insect Science》2019,26(3):545-554
Humankind draws important benefits from large-scale ecological processes termed ecosystem services, yet the status of several of them is declining. Reliable monitoring methods are essential for tracking the status of ecosystem services. Predation is the mainstay of natural pest control, a key ecosystem service. We used green plasticine caterpillars to monitor predation pressure, and to obtain baseline data on predator activity in transgenic Bt versus non-Bt maize fields in Old and New World countries. Predation pressure was measured at ground and canopy levels using an identical, small-plot experimental design in four European countries (Denmark, Slovakia, Romania and Italy) and Argentina. Total predation rate in maize was l l.7%d^-1 (min. 7.2%d^-1 in Argentina, max. 29.0%d^-1 in Romania). Artificial caterpillars were attacked both by invertebrates (mostly chewing insects with 42.0% of the attack marks, and ants with 7.1%, but also predatory and parasitoid wasps, spiders and slugs), and vertebrates (small mammals 25.5%, and birds 20.2%). Total predation at ground level (15.7%d^-1) was significantly higher than in maize canopies (6.0%d^-1) in all countries, except Argentina. We found no significant differences between predator pressure in Bt versus non-Bt maize plots. The artificial caterpillar method provided comparable, quantitative data on predation intensity, and proved to be suitable for monitoring natural pest control. This method usefully expands the existing toolkit by directly measuring ecological function rather than structure. 相似文献
2.
A. Mansion‐Vaquié M. Ferrante S. M. Cook J. K. Pell G. L. Lövei 《Journal of Applied Entomology》2017,141(8):600-611
The effectiveness of natural enemies to control pests can be enhanced through habitat manipulation. However, due to the differences in their ecology, generalist and specialist species may respond differently to the same manipulation. Moreover, interactions among natural enemies (i.e. cannibalism, intraguild predation, hyperparasitism) may complicate the assumption that a higher density of natural enemies would increase the level of biological control. We investigated the natural enemy guild composition and the predation rate along flower vs. grass margins at the edge of winter wheat (Triticum aestivum) fields in Denmark. Natural enemies were sampled by pitfall trapping and by suction sampling; predation intensity was measured using two different sentinel prey methods: artificial caterpillars made of plasticine, and sentinel aphid colonies. Specialist and generalist species responded differently to the two margin types: specialists (mostly parasitic wasps) were attracted by the flower margins, while generalists (ground beetles, rove beetles and spiders) were more active in grass margins. The number of artificial caterpillars attacked was significantly greater in grass margins (mean = 48.9%, SD = 24.3) than in flower margins (mean = 30.7%, SD = 17.4). We found a significant positive relationship between the number of artificial caterpillars attacked by chewing insects, and activity density for large (≥15 mm) ground beetles. Predation of sentinel aphids in wheat fields did not vary significantly in relation to margin type. Our results suggest that flowering margins may be beneficial for canopy‐active specialist natural enemies, but grassy margins are more useful for ground‐active generalist predators. 相似文献
3.
Arran Greenop Andreas Cecelja Ben A. Woodcock Andrew Wilby Samantha M. Cook Richard F. Pywell 《Journal of Applied Entomology》2019,143(4):380-386
Sentinel prey (an artificially manipulated patch of prey) are widely used to assess the level of predation provided by natural enemies in agricultural systems. Whilst a number of different methodologies are currently in use, little is known about how arthropod predators respond to artificially manipulated sentinel prey in comparison with predation on free‐living prey populations. We assessed how attack rates on immobilized (aphids stuck to cards) and artificial (plasticine lepidopteran larvae mimics) sentinel prey differed to predation on free‐moving live prey (aphids). Predation was assessed in response to density of the common invertebrate predators, a foliar‐active ladybird Harmonia axyridis (Coleoptera: Coccinellidae), and a ground‐active beetle Pterostichus madidus (Coleoptera: Carabidae). Significant increases in attack rates were found for the immobilized and artificial prey between the low and high predator density treatments. However, an increased predator density did not significantly reduce numbers of free‐living live aphids included in the mesocosms in addition to the alternate prey. We also found no signs of predation on the artificial prey by the predator H. axyridis. These findings suggest that if our assessment of predation had been based solely on the foliar artificial prey, then no increase in predation would have been found in response to increased predator density. Our results demonstrate that predators differentially respond to sentinel prey items which could affect the level of predation recorded where target pest species are not being used. 相似文献
4.
Andrew Howe Gabor L. Lövei & Gösta Nachman 《Entomologia Experimentalis et Applicata》2009,131(3):325-329
5.
The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a serious pest of many crops in North America, particularly sweet corn. The larvae of Coleomegilla maculata (DeGeer) (Coleoptera: Coccinellidae) are the most frequently observed predators of H. zea eggs in sweet corn. Companion cropping strategies have been developed to augment densities of C. maculata in sweet corn plantings. In this study, the importance of predation by C. maculata larvae was evaluated in experiments when larval abundance was manipulated using hand removal and physical exclusion. In 2003 and 2004, sentinel H. zea eggs were exposed on corn for 48 h. Egg mortality was 13.8% greater in the treatment where C. maculata larvae were present. In 2004 and 2005 eggs were exposed on corn under the same hand removal and physical exclusion techniques and monitored at 3-h intervals for 24 h to directly observe predation on sentinel eggs. Coleomegilla maculata larvae were the most frequently observed predators of the eggs, accounting for 45.9% of 85 total observed predation events in the control. Whereas in the treatment where C. maculata larvae were reduced, egg survival was 26.13% greater and only 37 total predation events were observed. All pest eggs were eliminated from individual ears 22.1% more often when C. maculata larvae were present at natural densities indicating that predation by this predator stage lessens crop damage by H. zea. The results of this study suggest that C. maculata larvae are an irreplaceable source of natural mortality for H. zea eggs on sweet corn. 相似文献
6.
G.C. Piubelli C.B. Hoffmann-Campo F. Moscardi S.H. Miyakubo & M.C.N. de Oliveira 《Entomologia Experimentalis et Applicata》2006,119(1):53-60
The velvetbean caterpillar, Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae), the major soybean [Glycine max (L.) Merrill (Fabaceae)] defoliator pest in Brazil can be controlled by a specific and virulent nuclear polyhedrosis virus (AgMNPV). Flavonoids such as rutin (quercetin 3‐O‐rhamnosylglucoside) were identified in soybean; it is known that this compound plays an important role in plant defense against lepidopteran pests. Studies were carried out to evaluate the biological and physiological activity of rutin (0.65 and 1.30%) on populations of A. gemmatalis resistant and susceptible to AgMNPV. Larvae from the resistant population were more negatively influenced by rutin, in comparison to larvae of the susceptible population, even with the addition of the lowest level of the flavonoid (0.65%) to the insect diet. The highest mortality (98%) was observed in the resistant population, when larvae fed on the diet containing 1.30% of rutin. Elongation of the feeding time, smaller initial larval weight, and pupal weight was observed on the virus‐resistant and ‐susceptible populations after adding 0.65 and 1.30% rutin to the diet. Larvae of the resistant population to AgMNPV fed on diet plus rutin 0.65% were also less efficient in the conversion of ingested and digested food into biomass. 相似文献
7.
Patrick F. Dowd Eric T. Johnson Karl E. Vermillion Mark A. Berhow Debra E. Palmquist 《Entomologia Experimentalis et Applicata》2011,141(3):208-215
Tropical plants are often more resistant to insects than temperate plants due to evolution of robust defenses to cope with a more constant insect threat. Coconut [Cocos nucifera L. (Arecaceae)] has very few chewing‐type leaf feeding insect pests and was tested for feeding suitability against two generalist leaf feeding caterpillar species, corn earworm, Helicoverpa zea (Boddie), and fall armyworm, Spodoptera frugiperda (J.E. Smith) (both Lepidoptera: Noctuidae). Feeding on leaf tissues from the most recently expanded leaves of a coconut variety caused significant mortality and reduced growth rates (as indicated by survivor weights) of S. frugiperda and H. zea compared to when they fed on leaves from a typical host, maize [Zea mays L. (Poaceae)], or the standard artificial diet. Proteins or other polymers did not appear to be responsible for the bioactivity noted against the caterpillars. Components responsible for activity were acetone extractable and separable by thin layer chromatography. Extracts from multiple areas of the thin layer chromatography (TLC) plates caused significant reductions in growth rates of S. frugiperda. The most bioactive TLC‐separated component, identified as pheophytin a, caused oxidative browning of test diets, suggesting that cytotoxicity of reactive oxygen species is a likely mode of action against H. zea and S. frugiperda. 相似文献
8.
Andy G. Howe Gösta Nachman Gábor L. Lövei 《Entomologia Experimentalis et Applicata》2015,154(2):161-170
Pest suppression by natural enemies is an important ecosystem service, which is a valuable resource to poor smallholders in developing countries. Diverse natural enemy assemblages of arthropod predators and parasitoids are documented in various regions in Africa, but our knowledge of their impact on herbivores in agroecosystems remains limited. We conducted experiments in cotton, Gossypium hirsutum L. (Malvaceae), under typical local agronomic practices in Uganda to assess levels of predation pressure ascribed to natural enemies. We measured predation rates on artificial caterpillars made of plasticine glued to cotton plants. Predation pressure on cotton fields varied between 1.96 and 4.1% per day, but was not significantly influenced by cotton treatments (insecticide/no insecticide, monocropping/intercropping with Phaseolus spp.). Predation pressure in non‐crop habitats adjacent to cotton fields was up to 12× higher than in the fields. Marks left on the artificial caterpillars revealed that arthropods and birds were largely accountable for predation in cotton fields, whereas arthropods and small mammals were dominant in non‐cultivated habitats. 相似文献
9.
Sentinel prey can provide a direct, quantitative measure of predation under field conditions. Live sentinel prey provides more realistic data but rarely allows the partitioning of the total predation pressure; artificial prey is less natural but traces left by different predators are identifiable, making it suitable for comparative studies. We reviewed the available evidence of the use of both types of invertebrate sentinel prey. Fifty‐seven papers used real prey, usually measuring predation on a focal (often pest) species, with studies overwhelmingly from North America. The median predation was 25.8% d?1. Artificial sentinel prey (45 papers) were used in both temperate and tropical areas, placed more above ground than at ground level. The most commonly used artificial prey imitated a caterpillar. Up to 14 predator groups were identified, registering a median of 8.8% d?1 predation; half the studies reported only bird predation. Predation on real prey was higher than on artificial ones, but invertebrate predation was not higher than vertebrate predation. Invertertebrate but not vertebrate predation was negatively related to prey size. Predation near the Equator was not higher than at higher latitudes, nor in cultivated than noncultivated habitats. The use of sentinel prey is not yet standardised in terms of prey size, arrangement, exposure period or data reporting. Due to the simplicity and ease of use of the method, such standardisation may increase the usefulness of comparative studies, contributing to the understanding of the importance and level of predation in various habitats worldwide. 相似文献
10.
South America is undergoing a rapid and large‐scale conversion of natural habitats to cultivated land. Ecosystem services still remain important but their level and sustainability are not known. We quantified predation intensity in an Argentinian agricultural landscape containing remnants of the original chaco serrano forest using artificial sentinel prey. We sought to identify the main predators and the effect of landscape configuration and maize phenology on predation pressure by invertebrate and vertebrate predators in this landscape. The most common predators were chewing insects (50.4% predation events), birds (22.7%), and ants (17.5%). Overall predation rates in forest fragments (41.6% per day) were significantly higher than in the surrounding maize fields (21.5% per day). Invertebrate predation was higher inside and at the edge of forest fragments than within fields, and did not change with increasing distance from a fragment edge, indicating a lack of spillover from the native habitat remnants to the cultivated matrix at the local scale. Distance from a continuous forest had a positive impact on predation by invertebrates and a negative impact on vertebrate predation. 相似文献
11.
Lise Roy Adrien Taudire Julien Papaïx Rumsais Blatrix Geoffrey Chiron Ghais Zriki Olivier Bonato Jean‐Yves Barnagaud 《Ecology and evolution》2020,10(18):9968-9980
- Pest regulation by natural enemies has a strong potential to reduce the use of synthetic pesticides in agroecosystems. However, the effective role of predation as an ecosystem service remains largely speculative, especially with minute organisms such as mites.
- Predatory mites are natural enemies for ectoparasites in livestock farms. We tested for an ecosystem level control of the poultry pest Dermanyssus gallinae by other mites naturally present in manure in poultry farms and investigated differences among farming practices (conventional, free‐range, and organic).
- We used a multiscale approach involving (a) in vitro behavioral predation experiments, (b) arthropod inventories in henhouses with airborne DNA, and (c) a statistical model of covariations in mite abundances comparing farming practices.
- Behavioral experiments revealed that three mites are prone to feed on D. gallinae. Accordingly, we observed covariations between the pest and these three taxa only, in airborne DNA at the henhouse level, and in mites sampled from manure. In most situations, covariations in abundances were high in magnitude and their sign was positive.
- Predation on a pest happens naturally in livestock farms due to predatory mites. However, the complex dynamics of mite trophic network prevents the emergence of a consistent assemblage‐level signal of predation. Based on these results, we suggest perspectives for mite‐based pest control and warn against any possible disruption of ignored services through the application of veterinary drugs or pesticides.
12.
Many studies in recent years have investigated the relationship between landscape complexity and pests, natural enemies and/or pest control. However, no quantitative synthesis of this literature beyond simple vote-count methods yet exists. We conducted a meta-analysis of 46 landscape-level studies, and found that natural enemies have a strong positive response to landscape complexity. Generalist enemies show consistent positive responses to landscape complexity across all scales measured, while specialist enemies respond more strongly to landscape complexity at smaller scales. Generalist enemy response to natural habitat also tends to occur at larger spatial scales than for specialist enemies, suggesting that land management strategies to enhance natural pest control should differ depending on whether the dominant enemies are generalists or specialists. The positive response of natural enemies does not necessarily translate into pest control, since pest abundances show no significant response to landscape complexity. Very few landscape-scale studies have estimated enemy impact on pest populations, however, limiting our understanding of the effects of landscape on pest control. We suggest focusing future research efforts on measuring population dynamics rather than static counts to better characterise the relationship between landscape complexity and pest control services from natural enemies. 相似文献
13.
Most people agree that arthropod natural enemies are good for insect pest management in agriculture. However, the population suppressive effects of predators, which consume their prey and often leave no direct evidence of their activity, are more difficult to study than the effects of parasitoids, which can be sampled from host populations relatively easily. We critically reviewed field studies which investigated the relationship between lepidopteran pests and their associated predatory fauna, published in 11 leading entomology and applied ecology journals between 2003 and 2008. Each study was appraised to determine whether or not it demonstrated that predators had an impact on prey (pest) populations and, if so, whether it was conducted at an ecological scale relevant to pest management. Less than half (43%) of the 54 field studies adopted methodologies that allowed the impact of predators on target pest populations to be measured. Furthermore, 76% of the studies were conducted at the scale of experimental plots rather than at the ecological scale which determines pest and predator population dynamics or at which pest‐management decisions are made. In almost one‐third of the studies, predator abundance and/or diversity was measured, but this metric was not linked with pest suppression or mortality. We conclude that much current research does not provide evidence that predatory arthropods suppress target lepidopteran pest populations and, consequently, that it has little relevance to pest management. Well‐designed ecological experiments combined with recent advances in molecular techniques to identify predator diets and the emergence of organic agriculture provide both the mechanisms and a platform upon which many predator–prey interactions can be investigated at a scale relevant to pest management. However, benefits will only be reaped from this opportunity if current approaches to research are changed and relevant ecological data are collected at appropriate ecological scales. 相似文献
14.
Md Habibullah Bahar John Stanley Peter Gregg Alice Del Socorro 《Entomologia Experimentalis et Applicata》2013,146(2):224-231
Experiments were conducted in small arenas and on whole plants to explore the effect of cotton aphids, Aphis gossypii Glover (Hemiptera: Aphididae), as alternative prey on the predation of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) larvae by green lacewing larvae, Mallada signatus Schneider (Neuroptera: Chrysopidae). Transgenic Bt (Bollgard II®) and conventional cotton plants were included to explore potential differences in the predator's performance on these cotton types. In small arenas, the presence of 20 aphids reduced predation on H. armigera larvae by 22% (from 5.5 to 3.3 of 10) by a single lacewing larva over a 24‐h period. The presence of H. armigera reduced predation on aphids by ca. 29% (from 16.8 to 11.0 of 20) over 24 h. On whole plants, the presence of alternative prey had no effect on the number of H. armigera larvae or aphids remaining after 3 days. The presence of H. armigera larvae alone, without the predator, caused a 24% reduction in the numbers of aphids on conventional, but not on Bt cotton plants. The combination of Bt cotton and lacewing larvae caused a 96.6% removal of early‐stage H. armigera larvae, a statistically significant increase over the addition of the proportions (91.6%) removed by each factor measured separately, providing evidence of synergism. These studies suggest that the presence of aphids as alternative prey would not necessarily disrupt the predation by green lacewing on larvae of H. armigera, especially on Bt cotton. 相似文献
15.
Mario V. Balzan Gionata Bocci Anna‐Camilla Moonen 《Entomologia Experimentalis et Applicata》2016,158(3):304-319
Increased plant diversity in cropping systems can play an important role in agriculture by enhancing arthropod‐mediated ecosystem services, including biological control and pollination. However, there is limited research investigating the concurrent influence of plant functional diversity within cultivated systems on different arthropod functional groups, the provision of multiple ecosystem services, and crop yield. During a field experiment, repeated over 2 years, we measured the effect of increasing plant functional diversity on community structure of arthropod visitors, the abundance of multiple pests and induced crop damage, and fruit production in two varieties of tomato. Plant resources (floral and extra‐floral nectar and pollen) were included within experimental plots in four levels, with each level increasing the plant functional group richness, based on floral morphology and availability of resources, in a replacement series. The presence of sown flower mixtures in experimental plots was associated with increased abundance and diversity of natural enemy functional groups and an enhanced abundance of bees (Hymenoptera: Apiformes). However, we only detected relatively small variability in arthropod visitors among types of mixtures, and increased abundance of natural enemies did not translate into stronger pest suppression or reduced crop damage. Lepidoptera pest damage was significantly higher in plots adjacent to wildflower strips, an ecosystem disservice, but a significantly higher crop productivity was recorded from these plots. Our results provide evidence that inclusion of non‐crop plant resources in agroecosystems can improve the conservation of beneficial arthropods and may lead to increased crop productivity. 相似文献
16.
Nathaniel J. Walton Matthew J. Grieshop 《Entomologia Experimentalis et Applicata》2016,159(3):375-377