Agricultural Habitats Research Articles

Ectoparasites associated with the Bushveld gerbil (Gerbilliscus leucogaster) and the role of the host and habitat in shaping ectoparasite diversity and infestations.

Rodents are known hosts for various ectoparasite taxa such as fleas, lice, ticks and mites. South Africa is recognized for its animal diversity, yet little is published about the parasite diversity associated with wild rodent species. By focusing on a wildlife-human/domestic animal interface, the study aims to record ectoparasite diversity and levels of infestations of the Bushveld gerbil, Gerbilliscus leucogaster, and to establish the relationship between ectoparasite infestation parameters and host- and habitat factors. Rodents (n = 127) were trapped in 2 habitat types (natural and agricultural) during 2014–2020. More than 6500 individuals of 32 epifaunistic species represented by 21 genera and belonging to 5 taxonomic groups (fleas, sucking lice, ticks, mesostigmatan mites and trombiculid mites) were collected. Mesostigmatan mites and lice were the most abundant and fleas and mesostigmatan mites the most prevalent groups. Flea and mesostigmatan mite numbers and mesostigmatan mite species richness was significantly higher on reproductively active male than female rodents. Only ticks were significantly associated with habitat type, with significantly higher tick numbers and more tick species on rodents in the natural compared to the agricultural habitat. We conclude that the level of infestation by ectoparasites closely associated with the host (fleas and mites) was affected by host-associated factors, while infestation by ectoparasite that spend most of their life in the external environment (ticks) was affected by habitat type.

The lure of the big city: smaller Danish rookeries are increasingly associated with urban land cover

Rooks Corvus frugilegus are common and widespread in urban and agricultural habitats in Denmark. Large numbers are killed annually by derogation shooting to control population growth to reduce noise near populated areas and prevent agricultural damage. Responding to increasing public complaints about noise nuisance from urban rookeries, we investigated changes in extent of urban and agricultural habitats within 500 m, 1000 m and 2000 m of all known breeding rook colonies (rookeries) in eastern Jutland, Denmark in 1991 compared to 2021 based on open access land cover GIS layers in 1990 and 2019. Numbers of rookeries increased by 40% from 95 (1991) to 133 (2021) but nest abundance increased only by 6% from 10,299 to 10,887 due to more and significantly smaller rookeries, increasingly associated with urban sites. In both years, the proportion of urban area within distance classes of rookeries was significantly higher, and the area of agriculture significantly lower, than at randomly chosen points in the same region. The proportion of urban area around each rookery decreased with increasing distance, whereas the proportion of agricultural land cover increased. The proportional area of urban land use within the distance classes increased between 1991 and 2021 whereas agricultural land cover decreased. Given no simultaneous major change in overall land use, our results indicate an increasing selection by rooks for smaller urban rookeries over agricultural landscapes, where rookeries have declined. We consider these trends, especially the proliferation of smaller rookeries in urban areas, as a potential explanation for the upsurge in public complaints about rookery noise in residential areas. We urge further research to explain the causes behind these trends before we can provide science-based solutions to resolve such conflicts effectively.

Latitudinal and anthropogenic effects on the structuring of networks linking blood-feeding flies and their vertebrate hosts.

Biting flies (Diptera) transmit pathogens that cause many important diseases in humans as well as domestic and wild animals. The networks of feeding interactions linking these insects to their hosts, and how they vary geographically and in response to human land-use, are currently poorly documented but are relevant to understanding cross-species disease transmission. We compiled a database of biting Diptera-host interactions from the literature to investigate how key interaction network metrics vary latitudinally and with human land-use. Interaction evenness and H2' (a measure of the degree of network specificity) did not vary significantly with latitude. Compared to near-natural habitats, interaction evenness was significantly lower in agricultural habitats, where networks were dominated by relatively few species pairs, but there was no evidence that the presence of humans and their domesticated animals within networks led to systematic shifts in network structure. We discuss the epidemiological relevance of these results and the implications for predicting and mitigating future spill-over events.

Exploring cattle sheds as complementary avifaunal habitat niches in rice dominated agricultural areas in Punjab, India

Avian diversity has often been studied in agricultural habitats, but ornithological aspect of cattle sheds has never been studied. This exploratory study was conducted with the objective of studying the potential of cattle sheds for sustaining avian abundance and diversity in rice dominated agricultural areas. The study was done in Rice Field Ecosystem (System I) and Cattle Shed Ecosystem (System II) during 2019 and 2020 monsoon crop season from selected villages, namely, Dangon, Pakhowal and Sarabha (district Ludhiana), Punjab. It was recorded that 26 avian species (mainly of grassland habitat) were present in cattle sheds from a total 34 avian species (wetland, grassland and open countryside inhabiting species) observed in rice fields, which reflected that cattle sheds support a wide proportion of avian fauna and complement rice fields in supporting and preserving avian abundance and diversity. There is immense need to explore and accordingly lay emphasis on boosting dairy as allied sector so that cattle sheds can be exploited in preservation of diverse avian populations and thereby reinforcing approach of sustainable agriculture. Keywords: Avian diversity, Avian feeding guilds, Cattle Shed, Grassland birds, Rice crop

Invasive Cirsium arvense displays different resource-use strategies along local habitat heterogeneity in thetrans-Himalayan region of Ladakh.

Climate change and anthropogenic pressures have resulted in a significant shift in the invasion susceptibility and frequency of non-native species in mountain ecosystems. Cirsium arvense (L.) Scop. (Family: Asteraceae) is an invasive species that spreads quickly in mountains, especially in the trans-Himalayan region of Ladakh. The current study used a trait-based approach to evaluate the impact of local habitat heterogeneity (soil physico-chemical properties) on C. arvense. Thirteen plant functional traits (root, shoot, leaf, and reproductive traits) of C. arvense were studied in three different habitat types (agricultural, marshy, and roadside). Functional trait variability in C. arvense was higher between, than within habitats (between different populations). All the functional traits interacted with habitat change, except for leaf count and seed mass. Soil properties strongly affect C. arvense's resource-use strategies across habitats. The plant adapted to a resource-poor environment (roadside habitat) by conserving resources and to a resource-rich environment (agricultural and marshy land habitat) by acquiring them. The ability of C. arvense to use resources differently reflects its persistence in introduced habitats. In summary, our study shows that C. arvense invades different habitats in introduced regions through trait adaptations and resource-use strategies in the trans-Himalayan region.

Transmission Mode and Assembly of Seed Fungal Endophyte Communities in Wheat and Wheat Wild Relatives

Seeds acquire fungal endophytes either from the environment or from their progenitors. These transmission modes are central in shaping the microbiome because they affect species composition and balance. We studied fungal endophyte communities (FECs) in three plant species: bread wheat ( Triticum aestivum), wild emmer wheat ( Triticum turgidum dicoccoides), and wild barley ( Hordeum spontaneum). We conducted two experiments to test seed-to-seed transmission: (i) we compared FECs in stems and seeds collected from agricultural and natural habitats and (ii) we grew plants under greenhouse conditions to isolate the effect of vertical transmission on the plant FECs. The analysis of seed communities revealed differences in FEC composition and diversity among plant species; however, Alternaria infectoria dominated FECs in all plant species. In field-collected plants, the number of taxa in the seeds was less than half the number in stems, and close to 90% of the seed taxa were found in stems. The FECs from stems and seeds of greenhouse-grown plants were more diverse than the FECs of original seeds; they lacked a single dominant taxon, and the FECs in the new seeds had a similar richness and diversity to stem FECs, with only 40% overlap. The controlled-environment experiment confirmed vertical transmission of certain species but also showed that external infection of the seeds is the main source for specific taxa. Our results show that many taxa can reach the seeds internally, albeit in different abundance, that both infection sources affect seed FEC composition, and that external conditions affect the balance between FECs within the plant.

Diet of snapper (Chrysophrys auratus) in green‐lipped mussel farms and adjacent soft‐sediment habitats

AbstractWild fish utilise aquaculture habitats for shelter and/or food resources. It is often assumed that fish respond to feed input, the abundance of the farmed species or the associated assemblage of biofouling which naturally colonises the structural habitats. However, few studies have directly analysed the composition of the diet of fish within aquaculture habitats, and of these most have focused on fed finfish aquaculture. Snapper are commonly present as adults within coastal mussel farms and tend to become a resident species of these farms. Therefore, they are a suitable case study species for exploring differences in diet between natural and aquaculture habitats. This study investigated the gut contents of snapper in soft‐sediment habitats within and outside of New Zealand green‐lipped mussel farms. Visual gut analysis and DNA metabarcoding methods were used to provide complementary analyses on the composition of gut contents between the mussel farm and natural (i.e., control) sites. Snapper within mussel farms were consistently found to have consumed different prey groups compared to the control snapper. Prey groups identified from mussel farm snapper gut contents could be directly linked to species commonly present in the farms, that is cultured green‐lipped mussels, blue mussels and barnacle biofouling. There was good alignment between the visual gut and genetic analyses for the key species identified. Overall, the results show that the highly abundant prey groups consumed by snapper in mussel farm habitats are likely to be beneficial to the snapper population, reducing foraging effort and potentially supplying more nutritious prey. These findings provide evidence towards the supporting services of mussel farm habitats through the provision of food resources.

Landscape fires disproportionally affect high conservation value temperate peatlands, meadows, and deciduous forests, but only under low moisture conditions

Landscape fires are a natural component of the Earth System. However, they are of growing global concern due to climate change exacerbating their multiple impacts on biodiversity, ecosystems, carbon storage, human health, economies, and wider society. Temperate regions are predicted to be at greatest risk of increasing fire activity due to climate change, where fires can seriously impact important ecosystems for biodiversity and carbon storage, such as peatlands and forests. There is insufficient literature on the background prevalence, distribution, and drivers of fires in these regions, especially within Europe, to assess and mitigate their risks. Using a global database of fire patches based on the MODIS FireCCI51 product, we address this knowledge gap by quantifying the current prevalence and size of fires in Polesia, a 150,000 km2 area comprising a mosaic of peatland, forest, and agricultural habitats in northern Ukraine and southern Belarus. Between 2001 and 2019, fires burned 31,062 km2 of land, and were most frequent in spring and autumn. Although most fires started in agricultural land, fires disproportionately affected natural and semi-natural land cover types, particularly in protected areas. Over one fifth of protected land burned. Coniferous forests were the most common land cover type in protected areas, but fires mostly occurred in meadows, open peatlands (especially fen and transition mires), and native deciduous forests. These land cover types were highly susceptible to fires under low soil moisture conditions, but the risk of fire was low under average or higher soil moisture conditions. Restoring and maintaining natural hydrological regimes could be an effective nature-based solution to increase the resilience of fire-vulnerable ecosystems and support global biodiversity and carbon storage commitments under the United Nations Framework Conventions on Climate Change and Convention on Biological Diversity.

Habitat suitability mapping of white stork Ciconia ciconia in one of its key European breeding areas

Due to rapid changes of the agricultural practice, the traditionally managed farmland became currently-one of the most endangered habitats in Europe. Species related to the rural landscape have been facing a great challenge of adaptation to quickly changing conditions. Therefore, recognizing and characterizing highly suitable areas for white storks is very important to plan conservation measures in the era of changes in agriculture and land use. Here, combining nest survey data (811 occupied nest), GIS-data on habitat availability and modelling approach, we characterize the current foraging conditions of the white stork Ciconia ciconia, an indicator of the agricultural habitat biodiversity and an umbrella species for organisms associated with agriculture landscape. The studied population breeds in the Warmińska Refuge Natura 2000 site (N Poland), one of the key breeding areas of this species in Europe. Breeding pair presence was predicted by the area of pasture, meadows, field ponds, and linear water within a 1 km buffer around the nest. The main hotspots of habitat suitability were located in the central and western parts of the study area, characterized by a more traditional model of agriculture. The distance to important foraging habitats does not influence white stork fecundity indicating that landscape composition is important when choosing the breeding site. The pairs with higher number of young were located further from other neighbouring pairs and at the areas with lower density of pairs in general. This is probably linked to the lower competition for food between more distant breeding pairs. Our results show that the traditional agricultural use in mosaics of pastures, meadows and aquatic habitats promotes white storks nesting.

An experimental analysis of consumers’ attitudes towards honey: The case of the Sicilian market

The Apis Mellifera is relevant for the structure, composition, and functioning of natural habitats, including agricultural habitats and urban and peri‑urban contexts. Indeed, Apis Mellifera has a massive impact in terms of the positive externalities it brings to the environment in general and especially in fruit trees. In addition to these aspects that determine positive effects on the environment, the production of honey, the consumption of which is of fundamental importance for human health, should not be overlooked. This research aims to investigate the factors that drive consumers to purchase and consume honey. For the purpose of the research, we did a stage sampling by dividing the municipalities in Sicily into three stages. The research results show that 327 out of 527 participants who consume honey because they consider it remarkable for its health and therapeutic properties. This aspect, combined with the positive externalities created by bees, results in the combination of multifunctional agricultural production where production for food purposes (honey) is combined with agricultural production. This aspect has a major value in a perspective of agricultural production that increasingly respects the environment and human health.

City-Region Food Systems and Biodiversity Conservation: The Case Study of the Entre-Douro-e-Minho Agrarian Region

Agriculture is the dominant form of land management with at least half of the species in Europe depending on agricultural habitats. Additionally, there is a growing demand for a more sustainable food system. In that context, food system relocalization and City-Region Food Systems (CRFS) are proposed for food resilience and environmental sustainability. This work represents the first attempt to map the relocalization of the potential foodshed (PF) of the Entre-Douro-e-Minho agrarian region, assessing its impacts on landscape heterogeneity and ecological value. The methodological approach, developed in a Geographic Information System, aimed to (1) map the ecological suitability of the study area, (2) propose a PF relocalization scenario, and (3) assess its impacts on land cover changes and landscape structure through landscape metrics. Outcomes of this research reflect land-use optimization concerning ecological suitability for agrarian uses, depicting the strong presence of temporary crops in the landscape. They also emphasize the need for greater detail in Land Use Plans, due to the vulnerability of coastal areas. Moreover, results revealed an increased landscape heterogeneity and related ecological value, highlighting the integration of landscape ecological properties into CRFS planning as a line of research and contributing to the implementation of land use compatible with biodiversity conservation.

Effects of Low Doses of a Novel dsRNA-based Biopesticide (Calantha) on the Colorado Potato Beetle.

The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) is a destructive pest of the cultivated potato, Solanum tuberosum. Members of this species are well-suited to agricultural habitats because of a suite of physiological adaptations and their ability to evolve resistance to multiple insecticides. Recently, a novel double-stranded RNA (dsRNA) insecticide (Calantha, active ingredient ledprona) has been demonstrated as an effective tool to manage Colorado potato beetle populations through RNA interference (RNAi). Previous studies have demonstrated the lethality of the high doses of ledprona but had not assessed possible effects of low doses that may happen due to product degradation in the environment, incomplete spray coverage, and foliage growth. Exposure of fourth instar larvae to low concentrations of ledprona interfered with their pupation. Exposure of adults significantly reduced their mobility after seven days, as well as their fertility. Reproductive effects were stronger in females, especially when exposed before reaching sexual maturity. The observed effects of low doses of ledprona may aid in the overall management of Colorado potato beetles by reducing the size of resident populations, inhibiting beetle movement within and between fields, and reducing the population growth rate.

The Disappearance of Small Mammal Carcasses in Human-Dominated Habitats: A Field Experiment in Northeastern Japan

Even in human-dominated regions such as urban and agricultural areas, there are organisms involved in the decomposition of animal carcasses. Therefore, it is possible that these complementary decomposition functions occur in different habitats. Here, we clarified the disappearance patterns of small mammal carcasses in forest and human-dominated (urban and agricultural) habitats in northeastern Japan, based on field experiments. All small mammal carcasses in both summer and autumn were removed by different scavengers within 6 days; therefore, there was little difference in the disappearance rate of carcasses between habitats. The scavenger groups that contributed to carcass removal of remains in the summer survey differed between sites, suggesting that the disappearance process varies with landscape and canopy openness conditions. Although many carcasses were removed by vertebrates during the autumn survey, the vertebrate species involved differed among the survey sites. This study suggests that ecological functions related to the decomposition of small mammal carcasses in anthropogenically modified habitats may be maintained by the complementary activities of vertebrates and invertebrates.

Acanthopagrus latus migration patterns and habitat use in Wanshan Islands, Pearl River Estuary, determined using otolith microchemical analysis

IntroductionThe waters surrounding the Wanshan Islands are important traditional fishing grounds in China, with rich habitat types. Acanthopagrus latus is an economically important species in this area; however, the distribution of its spawning grounds and habitat use patterns remain unknown.MethodsThus 100 otolith samples of A. latus were collected from three geographic areas (MW: Qi’ao Island Mangrove Water Habitat; OW: Yamen Estuary Oyster Farm Water Habitat; RW: Dong’ao-Guishan Island Reef Water Habitat), and the concentrations of Sr and Ca along the shortest axis of the vertical otolith annual or lunar rings were measured to span the entire life cycle of A. latus, with the core and edge areas corresponding to environmental characteristics at birth and capture, respectively.Results and discussionAnalysis of covariance (ANCOVA) revealed that the ratios of Sr/Ca in otolith edges of RW samples are significantly higher than those of OW and MW samples; however, both the values of Sr/Ca ratio in otolith cores collected from OW and MW are comparable with those of RW samples. Cluster analysis and non-metric multidimensional scaling (nMDS) indicated that at the juvenile stage, RW and MW individuals in the two main clusters belonged to the same cluster. There was no significant difference between the cores of the RW samples and the edges of the MW and OW samples. Therefore, the spawning area of A. latus in the Wanshan Islands is thought to have originated from low to medium-salinity waters with mangroves and oyster farm habitats in the Pearl River Estuary. A. latus from RW was found to have three distinct habitat-use patterns: 1) Marine Resident (7.2% of sampled fish) fish that remain in marine habitats for life; 2) Marine Migrant (16.4% of sampled fish) juveniles inhabit low to moderate salinity habitats and migrate to marine habitats as they grow; 3) Estuarine Visitor (76.4% of sampled fish) repeated migration between low to moderate salinity and marine habitats. This suggests widespread migration between estuarine and marine habitats throughout the ontogeny. The plasticity of this habitat use and the protection of spawning grounds should be considered in future fisheries management because A. Latus in this area has been the victim of the overexploitation of resources.

A range’s core should not only be important in research

A range’s core should not only be important in research

Assessing the role of invasive weeds in the impact of successional habitats on the bird assemblage in overgrowing agriculture

Agricultural habitats are assumed to be biodiversity refuges. However, some studies treat agricultural land management as a cause of the biodiversity decline, to which habitat loss and heterogeneity may contribute. Between the crops, the successional habitats appear – ruderal plant communities and bush areas. Their influence on farmland biodiversity is unknown. This research assessed the impact of spatial relationships between agricultural areas, semi-natural meadows and successional habitats on the bird species richness, Shannon diversity index, and Faith’s phylogenetic diversity index. An additional habitat variable was the presence of weeds, i.e., invasive Caucasian hogweeds Heracleum sp., treated as crops in the past. The birds and habitats research was on 74 sites set in pairs (invaded vs control) in south-eastern Poland. Results showed that birds assembling in agricultural and semi-natural areas were more diverse and contained protected farmland species, while birds appearing in overgrown habitats (i.e., successional and invaded) were clumped with their habitat requirements. In the presence of plant invaders, ruderal habitats negatively affected the bird phylogenetic diversity index. In invaded sites, bush areas had no positive effects on the Shannon diversity index and species richness of birds, in contrast with control sites. The presented research suggests the need to re-evaluate the importance of successional non-crop habitats considered positive in agricultural landscapes if those habitats develop in areas with plant invasion.

Beyond rural vs urban differences: A close match in european preferences in some basic wildlife management and conservation principles

The EU biodiversity strategy for 2030 sets out a framework of commitments and actions to tackle the main drivers of biodiversity loss. Such framework needs to be built on a whole-of-society approach to biodiversity protection, mobilizing private and public funding. In this context, our goal was estimating societal support and preferences about some basic wildlife management principles, which may be useful to inform EU decision-makers about societal priorities and other additional funding sources for wildlife conservation. A discrete choice experiment was conducted by 2415 inhabitants in six European countries (Spain, France, Italy, UK, Germany, Sweden), including residents in both rural (47% of respondents) and urban areas. Our findings reveal a clear pattern across western Europe with similar trends along the studied countries, and even between rural and urban citizens, on some basic wildlife management principles. According to our survey, payments for environmental services contribute to achieving a higher well-being from European citizens in any of the prospective wildlife programs considered, which suggests it is an acceptable tool to share out funds for biodiversity conservation. In addition, managing scarce species is preferred over managing too abundant species; management in forest, agricultural and aquatic habitats is prioritized over that in urban landscapes; and management in protected areas is preferred over management in non-protected ones. These findings suggest that there is a common culture in Europe related to the management of wildlife even when considering citizens with contrasted ways of life: rural vs urban citizens from northern to southwestern Europe. Overall, this study may help in the design of wildlife management policies that maximize societal acceptability and gather higher support.

Drug Discovery – A New Bioactive Compounds Isolated from Natural Sources

"A rise in mortality due to fungal infections in an immunocompromised population has been observed lately. Nowadays, due to increased fungal infections, the limitations encountered in their treatment like resistance, side-effects, and high toxicity, the rising prescription and overuse of conventional antifungals all stimulate a search for alternative natural drugs therefore we are in dire need of natural newer strategies that involve reliable agents for the treatment of fungal diseases such as essential oils are known for their anti-microbial properties and are multi-component. Materials & Methods: Soil samples (66 samples) were collected from different agricultural fields and animals habitat of Saharanpur (U.P.) Isolation of keratinophilic fungi was carried out by the hair-baiting technique. Extraction of Mentha piperita & Cinnamonum vernum essential oil was carried out by hydrodistillation method and the chemical composition of both extracted essential oils was determined by Gas ChromatographyMass Spectrophotometry. Antimycotic studies of essential oils were done by the standard disc diffusion method. Results & Discussion: In the present study, the antifungal potential of Mentha piperita & Cinnamonum vernum essential oils were evaluated against three human pathogenic fungi isolated from the soil of agricultural field and animals habitat of Saharanpur (U.P.) i.e Trichophyton mentagrophytes, T.tonsurans, and T.equinum. The chemical composition of Mentha piperita & Cinnamonum vernum EO was analyzed by GC-MS. Menthol (53.28%) was the major compound of the Mentha piperita EO followed by Menthyl acetate (15.1%) and Menthofuran (11.18%). Major constituents of Cinnamonum vernum EO were linalool (8%), (E)- cinnamaldehyde (7.2%), β-caryophyllene (7.4%), eucalyptol (6.4%), and eugenol (5.6%). Conclusion: Essential oils of Mentha piperita & Cinnamonum vernum have been found to have remarkable & excellent antifungal activity against these pathogenic fungi. Present findings conclude that natural products like plant-derived EOs instead of chemotherapy and the emergence of resistance to antifungal drugs can be regarded as an environmental safety mode of disease control against pathogens. "

Fine-Scaled Selection of Resting and Hunting Habitat by Leopard Cats (Prionailurus bengalensis) in a Rural Human-Dominated Landscape in Taiwan.

Wildlife is increasingly forced to live in close proximity to humans, resulting in human-wildlife conflict and anthropogenic mortality. Carnivores persisting in human-dominated landscapes respond to anthropogenic threats through fine-scaled spatial and temporal behavioral adjustments. Although crucial for conservation, quantitative information on these adjustments is scarce. Taiwan's endangered leopard cat occurs in rural human-dominated landscapes with a high anthropogenic mortality risk. To survive, the nocturnal leopard cat needs suitable habitats for foraging and safe refuge for resting during daytime hours when human activity peaks. In this study, we tracked seven VHF-collared leopard cats. To determine habitat selection patterns, we compared land use at nighttime locations and daytime resting sites with random points and fine-scaled vegetation characteristics at daytime resting sites with random points. Leopard cats selected natural habitats for nighttime hunting and avoided manmade and, to a lesser extent, agricultural habitats or used them according to availability. For daytime resting, leopard cats selected natural habitats and, to a lesser extent semi-natural habitats, such as unused land and abandoned orchards. Resting sites were preferentially situated in natural habitats, with little visibility (<2 m), shrubs, reed and stones, away from areas with high levels of human activity. This suggests leopard cats use a proactive strategy to avoid human encounters, which was supported by the reduced temporal overlap with humans and domestic dogs on agricultural land. Resting sites were placed ca. 1 km apart, 12.9 ± 0.3 m (mean ± SE) from the patch's edges, in patches with a size of 1.21 ± 0.04 ha (mean ± SE). Our results will assist in identifying and preserving suitable resting habitats to support leopard cat conservation.

Apparent niche differences between native and exotic lady beetles

Generalist predators can enhance biological control by filling unique niches and complementing other natural enemies, or disrupt it by preying upon other predators and parasitoids, complicating their net value for biological control. We searched for evidence of complementarity and/or interference between native (primarily Eriopis chilensis and E. eschscholtzi) and exotic (primarily Hippodamia variegata and Harmonia axyridis) lady beetles attacking aphids in alfalfa (Medicago sativa) fields near Santiago, Chile. Across 60 fields and three growing seasons, exotic lady beetle adults and larvae reached peak abundance relatively earlier in the growing season than the natives. Furthermore, exotic lady beetle peaks aligned more closely with aphid peak abundance than did native lady beetle peaks. Abundances of native lady beetle adults and larvae were weakly positively correlated with those of exotics, and peak aphid densities were generally lowest in fields where native and non-native lady beetle adults were similarly abundant. Therefore, we did not see evidence of strong interference between exotics and natives. Natural-agricultural habitat edges reduced native, but not exotic, larval lady beetle lag behind aphid peaks and was associated with greater lady beetle and lower aphid densities. Moreover, farms embedded in landscapes with greater natural habitat cover supported more exotic, but not native, lady beetles, and increased the lag between larval lady beetles and aphids for natives but not exotics. These findings support the idea that farms embedded within mosaics of natural and agricultural habitats may provide greater interaction potential between native lady beetles and aphid pests on farms as they move across the landscape, leading to greater top-down control. In contrast, exotic lady beetle lags were unaffected by landscape composition or configuration, but their greater densities in farms surrounded by more natural habitats might reflect a 'concentration effect' whereby exotic lady beetle abundance becomes concentrated in the agricultural habitats that they prefer. Our findings suggest that some lady beetles introduced for biocontrol may be better adapted to intensively managed habitats than natives, possibly leading to spatiotemporal complementarity between native and exotic lady beetles.