Natural enemies depend on remnant habitat size in agricultural landscapes

In agricultural landscapes, non-crop habitats, such as forest fragments, may not only play an important role for natural enemies, but may also favor some pests. However, there is a lack of studies in Neotropical regions about these interactions. Thus, the aim of this study was to investigate aphid parasitoidism at two distances (25 m and 525 m) from edges of forest fragments adjacent to wheat crops. This research was carried out in four wheat fields in the north of the Parana state, Brazil, during the planting season of 2009. In total, 8,392 aphids were counted, representing two species. There were 589 total aphid-parasitized (“mummies”), represented by six species. In all four areas, aphid abundance and parasitoidism showed no clear relationship to distance from forest fragments (25 m and 525 m). In addition, inverse density dependence between aphids and parasitoidism was observed. In summary, this study does not support the hypothesis of higher parasitoidism of aphids near edges of forest fragments. However, this is the first study in the Neotropical region and more research must be done to better understand this tritrophic interaction.

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Effects of distance from semi-natural habitat on fall armyworm (Spodoptera frugiperda, J. E. Smith) and its potential natural enemies in Ghana

Bulletin of Entomological Research ◽

10.1017/s0007485321000894 ◽

2021 ◽

pp. 1-11

Author(s):

Matthew W. Jordon ◽

Talya D. Hackett ◽

Fred Aboagye-Antwi ◽

Vincent Y. Eziah ◽

Owen T. Lewis

Keyword(s):

Natural Enemies ◽

Spodoptera Frugiperda ◽

Natural Habitat ◽

Fall Armyworm ◽

Agricultural Landscapes ◽

Sub Saharan Africa ◽

Leaf Damage ◽

Crop Damage ◽

Biological Pest Control ◽

Sub Saharan

Abstract Insect crop pests are a major threat to food security in sub-Saharan Africa. Configuration of semi-natural habitat within agricultural landscapes has the potential to enhance biological pest control, helping to maintain yields whilst minimising the negative effects of pesticide use. Fall armyworm (Spodoptera frugiperda, J. E. Smith) is an increasingly important pest of maize in sub-Saharan Africa, with reports of yield loss between 12 and 45%. We investigated the patterns of fall armyworm leaf damage in maize crops in Ghana, and used pitfall traps and dummy caterpillars to assess the spatial distribution of potential fall armyworm predators. Crop damage from fall armyworm at our study sites increased significantly with distance from the field edge, by up to 4% per m. We found evidence that Araneae activity, richness and diversity correspondingly decreased with distance from semi-natural habitat, although Hymenoptera richness and diversity increased. Our preliminary findings suggest that modifying field configuration to increase the proximity of maize to semi-natural habitat may reduce fall armyworm damage and increase natural enemy activity within crops. Further research is required to determine the level of fall armyworm suppression achievable through natural enemies, and how effectively this could safeguard yields.

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Edges in Agricultural Landscapes: Species Interactions and Movement of Natural Enemies

PLoS ONE ◽

10.1371/journal.pone.0059659 ◽

2013 ◽

Vol 8 (3) ◽

pp. e59659 ◽

Cited By ~ 48

Author(s):

Sarina Macfadyen ◽

Warren Muller

Keyword(s):

Natural Enemies ◽

Species Interactions ◽

Agricultural Landscapes

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Linear woody landscape elements may help to mitigate leaf surface loss caused by the cereal leaf beetle

Landscape Ecology ◽

10.1007/s10980-020-01097-3 ◽

2020 ◽

Vol 35 (10) ◽

pp. 2225-2238

Author(s):

Károly Lajos ◽

Orsolya Császár ◽

Miklós Sárospataki ◽

Ferenc Samu ◽

Ferenc Tóth

Keyword(s):

Biological Control ◽

Natural Enemies ◽

Natural Enemy ◽

Leaf Surface ◽

Leaf Beetle ◽

Agricultural Landscapes ◽

Natural Habitats ◽

Landscape Elements ◽

Surface Loss ◽

Cereal Leaf Beetle

Abstract Context Woody semi-natural habitats serve as permanent habitats and hibernation sites for natural enemies and, through spillover processes, they play an important role in the biological control of insect pests. However, this service is also dependent on the amount and configuration of the dominating woody habitat types: linear landscape elements (hedgerows, shelterbelts), and more evenly extended plantations. Relating natural enemy action to the landscape context can help to identify the effect of woody habitats on biological control effectiveness. Objectives In the Central European agricultural landscapes such as in the Hungarian lowlands, where our study took place, woody linear elements are characterised by high, while woody areal elements, mostly plantations, by low biological and structural diversity. In this study, we aimed to determine which composition and configuration of woody linear and areal habitats in the landscape may enhance the effect of natural enemy action on plant damage caused by the cereal leaf beetle (CLB, Oulema melanopus). Methods Herbivory suppression by natural enemies was assessed from the leaf damage difference between caged and open treatments. These exclusion experiments were carried out in 34 wheat fields on plants with controlled CLB infections. The results were related to landscape structure, quantified by different landscape metrics of both woody linear and areal habitats inside buffers between 150 and 500 m radii, surrounding the wheat fields. Results The exclusion of natural enemies increased the leaf surface loss caused by CLBs in all fields. Shelterbelts and hedgerows in 150–200 m vicinity of the wheat fields had a strong suppressing effect on CLB damage, while the presence of plantations at 250 m and further rather impeded natural enemy action. Conclusions Our results indicate that shelterbelts and hedgerows may provide a strong spillover of natural enemies, thus contribute to an enhanced biological control of CLBs.

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Association between patterns in agricultural landscapes and the abundance of wheat aphids and their natural enemies

EUROPEAN JOURNAL OF ENVIRONMENTAL SCIENCES ◽

10.14712/23361964.2015.12 ◽

2013 ◽

Vol 3 (2) ◽

pp. 101-108

Author(s):

Jun-He Liu ◽

Ming-Fu Yu ◽

Wen-Yi Cui ◽

Li Song ◽

Zi-Hua Zhao ◽

...

Keyword(s):

Natural Enemies ◽

Agricultural Landscapes

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Organic farming expansion drives natural enemy abundance not diversity in agricultural landscapes

10.1101/688481 ◽

2019 ◽

Author(s):

Lucile Muneret ◽

Arthur Auriol ◽

Olivier Bonnard ◽

Sylvie Richart-Cervera ◽

Denis Thiéry ◽

...

Keyword(s):

Biodiversity Conservation ◽

Organic Farming ◽

Natural Enemies ◽

Natural Enemy ◽

Farming Systems ◽

Crop Productivity ◽

Agricultural Landscapes ◽

List Type ◽

Natural Habitats ◽

Ecological Intensification

AbstractOrganic farming is seen as a prototype of ecological intensification able to conciliate crop productivity and biodiversity conservation in agricultural landscapes. However, how natural enemies, an important functional group supporting pest control services, respond to organic farming at different scales and in different landscape contexts remain unclear.Using a hierarchical design within a vineyard-dominated region located in southwestern France, we examine the independent effects of organic farming and semi-natural habitats at the local and landscape scales on natural enemies.We show that the proportion of organic farming is a stronger driver of species abundance than the proportion of semi-natural habitats and is an important facet of landscape heterogeneity shaping natural enemy assemblages. Although our study highlight a strong taxonomic group-dependency about the effect of organic farming, organic farming benefits to dominant species while rare species occur at the same frequency in the two farming systems.Independently of farming systems, enhancing field age, reducing crop productivity, soil tillage intensity and pesticide use are key management options to increase natural enemy biodiversity.Synthesis and Applications. Our study indicates that policies promoting the expansion of organic farming will benefit more to ecological intensification strategies seeking to enhance ecosystem services than to biodiversity conservation.

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Screening Drought-Tolerant Native Plants for Attractiveness to Arthropod Natural Enemies in the U.S. Great Lakes Region

Environmental Entomology ◽

10.1093/ee/nvz134 ◽

2019 ◽

Author(s):

Daniel R Gibson ◽

Logan Rowe ◽

Rufus Isaacs ◽

Douglas A Landis

Keyword(s):

Great Lakes ◽

Plant Species ◽

Natural Enemies ◽

Native Species ◽

Habitat Management ◽

Echinacea Purpurea ◽

Agricultural Landscapes ◽

Floral Resources ◽

Great Lakes Region ◽

Monarda Fistulosa

Abstract Arthropods provide a variety of critical ecosystem services in agricultural landscapes; however, agricultural intensification can reduce insect abundance and diversity. Designing and managing habitats to enhance beneficial insects requires the identification of effective insectary plants that attract natural enemies and provide floral resources. We tested the attractiveness of 54 plant species with tolerance to dry soils, contrasting perennial forbs and shrubs native to the Great Lakes region to selected non-native species in three common garden experiments in Michigan during 2015–2016. Overall, we found 32 species that attracted significantly more natural enemies than associated controls. Among these, Achillea millefolium and Solidago juncea were consistently among the most attractive plants at all three sites, followed by Solidago speciosa, Coreopsis tripteris, Solidago nemoralis, Pycnanthemum pilosum, and Symphyotrichum oolantangiense. Species which attracted significantly more natural enemies at two sites included: Asclepias syriaca, Asclepias tuberosa, Monarda fistulosa, Oligoneuron rigidum, Pycnanthemum virginianum, Dasiphora fruticosa, Ratibida pinnata, Asclepias verticillata, Monarda punctata, Echinacea purpurea, Helianthus occidentalis, Silphium integrifolium, Silphium terebinthinaceum, Helianthus strumosus, and Symphyotrichum sericeum. Two non-native species, Lotus corniculatus, and Centaurea stoebe, were also attractive at multiple sites but less so than co-blooming native species. Parasitic Hymenoptera were the most abundant natural enemies, followed by predatory Coleoptera and Hemiptera, while Hemiptera (Aphidae, Miridae, and Tingidae) were the most abundant herbivores. Collectively, these plant species can provide floral resources over the entire growing season and should be considered as potential insectary plants in future habitat management efforts.

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Effects of Flower-Enriched Ecological Focus Areas on Functional Diversity Across Scales

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.629124 ◽

2021 ◽

Vol 9 ◽

Author(s):

Lovisa Nilsson ◽

Björn K. Klatt ◽

Henrik G. Smith

Keyword(s):

Natural Enemies ◽

Critical Issue ◽

Solitary Bees ◽

Agricultural Landscapes ◽

Negative Results ◽

Ecological Focus Areas ◽

Environmental Measures ◽

Intensively Managed ◽

Cereal Fields ◽

Solitary Bees And Wasps

Ecological Focus Areas (EFAs) to benefit biodiversity became mandatory in intensively farmed landscapes after the reform of the European Common Agricultural Policy (CAP) in 2013. The implementation of EFAs as uncropped field margins has been criticized as ineffective but created a window of opportunity to test if augmenting them with annual flower strips can benefit biodiversity. In this study, we investigated if annual flower strips on EFAs benefited functional biodiversity in intensively farmed landscapes. To this end we established eleven annual flower strips with a seed mixture targeted for both natural enemies and pollinators, on areas were farmers had planned for EFAs. We determined effects on aphids and their natural enemies in cereal fields close to six of the flower strips, and for solitary bees and wasp close to and in the surroundings of all eleven flower strips. We found that annual flower strips benefited the abundance of hoverfly larvae and possibly also that of solitary bees. However, there were neither any significant effects on natural enemies (other than hoverfly larvae), nor any difference in natural pest control as shown by lack of differences in aphid numbers and parazitation rates. Abundances of solitary bees and wasps in the surrounding landscapes were unaffected, although there was a tendency for more solitary bee cells closer to the strips. We suggest that the critical issue leading to the mostly negative results is the lack of permanent structures to sustain populations of arthropods that in turn can benefit from annual flower strips. Hence, future agri-environmental policies need to carefully consider if and how annual agri-environmental measures should be implemented in intensively managed agricultural landscapes, e.g., by combining them with more permanent structures.

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The behaviour of hoverfly larvae (Diptera, Syrphidae) lessens the effects of floral subsidy in agricultural landscapes

10.1101/045286 ◽

2016 ◽

Author(s):

Elsa A. Laubertie ◽

Steve D. Wratten ◽

Alexandra Magro ◽

Jean Louis RGM Hemptinne

Keyword(s):

Biological Control ◽

Natural Enemies ◽

Laboratory Experiments ◽

Landscape Management ◽

Agricultural Landscapes ◽

Floral Resources ◽

Insect Behaviour ◽

Resource Concentration ◽

Conspecific Density ◽

Set Up

Modern agricultural landscapes favour crop pests: herbivores benefit from resource concentration and/or the absence of natural enemies in large areas of intensively farmed fields interspersed by small fragments of natural or non-crop habitats. Conservation biological control (CBC) aims at increasing the functional diversity of agricultural landscapes to make them more hospitable to natural enemies, and less to herbivores. Although natural enemies readily respond to this management, very few studies assess if they succeed in effectively protecting crops. We set up a field experiment to study if an ecological infrastructure varying in size and consisting of the provision of floral resources at the centre of lettuce plots would influence the number of eggs laid by hoverflies, and ultimately the control of lettuce aphids. We found that the hoverfly females lay more eggs in the plots with the larger flower resource compared to the control. However, this response had no impact on the abundance of aphids on the lettuces. We designed two laboratory experiments to understand this absence of response. We found mutual interference between hoverfly larvae, and suggest it may undermine the biological control of aphids. This mismatch between landscape management and the response of hoverflies indicates CBC should take into account insect behaviour, particularly their response to conspecific density, additionally to landscape ecology.

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