Number Of Predators Research Articles

Optimal control problem of a discrete spatiotemporal prey–predator three-species fishery model

In this work, we discuss a spatiotemporal discrete prey–predator model. It consists of three compartments: prey, predator, and super-predator. The proposed model describes the interaction between prey, predator, and super-predator in a region with a discrete displacement. We also provide research on appropriate regional control strategies. The controls are applied to the predator and the super-predator, respectively; they represent catching these in measured quantities in a space and a time chosen. The aim is to increase the number of prey and reduce the number of predators, restore the food chain system, and ensure its sustainability. Finally, we provide graphical visuals and numerical simulations to support our analytical findings.

Smallholder agriculture in African dryland agroecosystems has limited impact on trophic group composition, but affects arthropod provision of ecosystem services

Agricultural intensification is a major driver of biodiversity loss, but the majority of studies highlighting these threats come from industrialised agriculture in temperate countries of the global North. However, more than 30% of global food production is produced by smallholder farmers, particularly in Africa. We know very little about the impact of these farming practices on arthropod communities and associated ecosystems in dryland agroecosystems. We investigated the trophic group composition of arthropod communities (detritivorous, herbivorous, predatory & mixed feeders) and levels of associated ecosystem functions in replicated maize fields, paired adjacent natural bushveld habitats and the edge habitats between them in north-eastern Namibia and central-eastern Botswana during the dry and wet seasons. Predator activity densities differed significantly between habitats depending on the season, with higher numbers in natural habitats in the wet season but lower numbers in the dry season compared to maize fields. In general, edge habitats had higher numbers of predators than the other habitats. Predator attack rates on artificial caterpillars in both seasons and dung removal in the wet season were higher in habitats with natural vegetation (natural and edge). However, dung removal in the dry season and herbivory in the wet season were highest in the maize fields, the latter due to high level of fall armyworm infestation. Wet season multifunctionality was higher in natural habitats in Botswana, and to a lesser extent in Namibia, than in maize fields. Smallholder agriculture is not detrimental to decomposers, herbivores and mixed feeders compared to adjacent natural habitats, but may be detrimental to the provision of some ecosystem services. These results highlight the challenge of sustainably managing dryland agricultural land that is marginal for crop production, while providing smallholders with an optimal environment to benefit from the ecosystem services associated with arthropod communities. New conservation agriculture practices need to support the production of higher and more stable yields over time, while maintaining the limited impact of smallholder agriculture on biotic communities.

Rapid population decline in McKay’s Bunting, an Alaskan endemic, highlights the species’ current status relative to international standards for vulnerable species

Abstract The McKay’s Bunting (Plectrophenax hyperboreus) is endemic to Alaska, breeds solely on the remote and uninhabited St. Matthew and Hall islands (332 km2) in the central Bering Sea, and is designated as a species of high conservation concern due to its small population size and restricted range. A previous hypothesized population estimate (~2,800 to 6,000 individuals) was greatly increased (~31,200 individuals) after systematic surveys of the species’ entire breeding range in 2003, establishing McKay’s Bunting as one of the rarest passerines in North America. In 2018, we replicated the 2003 surveys and used density surface models to estimate breeding season densities, distributions, and population change over the intervening time period. Our results indicate that the McKay’s Bunting population declined by 38% (95% CI: 27 to 48%) from ~31,560 to 19,481 individuals since 2003. Spatial model predictions showed no areas with an increase of birds on either St. Matthew or Hall islands but revealed declines across 13% (42 km2) of St. Matthew Island. Declines disproportionately occurred both in marginal habitats with reduced rocky nesting substrate and in high-density hotspots along the coast of St. Matthew Island. The total area occupied by breeding adults decreased by 8%, and high-density hotspots shifted inland from the coast of St. Matthew Island to higher elevations on both islands, the latter potentially responses to exceptionally warm weather and reduced spring snow cover in 2018. Additionally, we observed low numbers of predators and interspecific competitors in 2018, suggesting that these did not cause the decline. Our findings indicate that McKay’s Bunting meets international standards for elevating its conservation status from Least Concern to Endangered based on the International Union for Conservation of Nature Red List of Threatened Species ranking criteria. Additional population monitoring and studies to identify the causal mechanisms of the recent population decline of this rare species could assist future population assessments.

Rove beetle communities (Coleoptera: Staphylinidae) in the rock dumps after coal mining

Rock dumps formed as a result of coal mining are unique model for studying the rove beetle communities. In total 60 species, 38 genera, 7 subfamilies of rove beetles were registered using soil traps. The greatest diversity of rove beetles was noted in forb-grass meadows (H` = 2.89) and pine plantations (H` = 2.39). The diversity of rove beetles was low (H` = 1.11) in birch and aspen-fir forests despite the greater number of revealed species. Only two eurytopic and mesophilic species (Drusilla canaliculata and Xantholinus linearis) were dominant in the rock dumps. Most of the rove beetles were eurytopic or forest species, zoophagous or mixophagous, mesophilous or hygrophilous. The number of eurytopic species and obligate predators increased, and the dynamic density of beetles decreased from older to younger dumps. The number of rove beetles depended on the soil temperature and humidity and the vegetation cover. Rove beetle communities are good indicators for monitoring the restoration of areas that have been technically degraded.

Kin-recognition and predation shape collective behaviors in the cannibalistic nematode Pristionchus pacificus.

Kin-recognition is observed across diverse species forming an important behavioral adaptation influencing organismal interactions. In many species, the molecular mechanisms involved are difficult to characterize, but in the nematode Pristionchus pacificus molecular components regulating its kin-recognition system have been identified. These determine its predatory behaviors towards other con-specifics which prevents the killing and cannibalization of kin. Importantly, their impact on other interactions including collective behaviors is unknown. Here, we explored a high altitude adapted clade of this species which aggregates abundantly under laboratory conditions, to investigate the influence of the kin-recognition system on their group behaviours. By utilizing pairwise aggregation assays between distinct strains of P. pacificus with differing degrees of genetic relatedness, we observe aggregation between kin but not distantly related strains. In assays between distantly related strains, the aggregation ratio is frequently reduced. Furthermore, abolishing predation behaviors through CRISPR/Cas9 induced mutations in Ppa-nhr-40 result in rival strains successfully aggregating together. Finally, as Caenorhabditis elegans are found naturally occurring with P. pacificus, we also explored aggregation events between these species. Here, aggregates were dominated by P. pacificus with the presence of only a small number of predators proving sufficient to disrupt C. elegans aggregation dynamics. Thus, aggregating strains of P. pacificus preferentially group with kin, revealing competition and nepotism as previously unknown components influencing collective behaviors in nematodes.

Biodiversity and Succession of Insects of Blackgram (Vigna mungo (L.) Hepper) During rabi in the Western Undulating Zone of Odisha

The field experiment was conducted to study about insect biodiversity and their succession in blackgram crop at the crop research farm, College of Agriculture, OUAT, Bhawanipatna during rabi 21. Twenty seven insects belong to seven orders and twenty two families were recorded during different growth stages of crop in an overlapping manner. Beside the insects twelve numbers of predators, three numbers of parasitoids and two pollinators were also noticed. The highest diversity index and evenness of insects were recorded at 42 SMW (0.902 and 1.000) followed by 50 SMW (0.833 and 0.710) respectively. The diversity of insects was almost uniform because of the evenness of the species. The insect order homoptera and the insect white fly came under superdominant class of dominance during all the growth stages of crop, whereas coleoptera and hemiptera were categorized under sub-dominant class at vegetative stage and flowering to podding stage of crop growth respectively. The insect orders hemiptera, coleoptera, diptera and hymenoptera and the insects i.e., galerucid beetle, jassid, stem fly, aphids and thrips came under recedent class of dominance. The relative abundance and dominant status of insect’s revealed that the maximum numbers of insects were belongs to orders homoptera (75.22%) followed by hemiptera (7.92%), coleoptera (6.30%), diptera (4.62%), hymenoptera (4.05%), orthoptera (0.89%), lepidoptera (0.86%) and odonata (0.09%).Chrysomelid beetles were noticed first during the early vegetative stage of crop followed by stem fly, white fly, leaf webber and semiloopers at the vegetative stage, tobacco caterpillar from late vegetative to pod filling stage, thrips in flowering stage, pod borers, pod bugs, aphids, pentatomid bugs and bihar hairy caterpillar from flowering to crop maturity stage and the pod fly and pod wasp from pod filling to pod maturity stage of the crop. Jassids, grasshoppers and predators like spiders, coccinellids beetles and parasitoids were appeared from mid vegetative stage and continued till fag end of the crop. The peak activities of insects were recorded from flowering to pod maturity stage of the crop.

Bioaccumulation and biomagnification of heavy metals in marine micro-predators

Nematodes represent >3/5 of the abundance of the world’s metazoans and usually account for nearly 90% of the total benthic fauna, playing a key ecological role in the benthic ecosystem functioning on a global scale. These small metazoans include a relevant number of microscopic predators and, in turn, are the most abundant preys of macro-megafauna and fish juveniles thus playing a key role in marine food webs. Here, using two independent approaches, we test the bioaccumulation in marine nematodes of several heavy metals present in contaminated sediments. We report here that nematodes, despite their short life cycle and small size, bioaccumulate significantly heavy metals. Bioaccumulation increases from deposit feeders and microalgal grazers to predators of microbes and other tiny metazoans. These results suggest that nematodes also contribute to their biomagnification along the food webs and can contribute to increase the transfer of contaminants from the sediments to larger organisms.

Dynamics of Zooplankton Consumption by the Three-speed Stickleleback <i>Gasterosteus aculeatus</i> (Linnaeus, 1758) at Different Densities of the Predator

An experiment was set up to estimate the rate of zooplankton consumption by the three-spined stickleback Gasterosteus aculeatus (Linnaeus, 1758) at different predator densities. A differential equation describes the dynamics of zooplankton abundance depending on duration of predator feeding. The derived function accurately characterizes the rate of zooplankton consumption by stickleback in the experiment, demonstrating a good agreement between the theoretical prerequisites and the experimental results. The relationship between changing a number of prey during predation, its mortality and consumption rate was revealed. The hypothesis of consumption rate proportional to the number of predators was tested. A comparative analysis of ingestion rate as a function of time and a function of prey density was performed.

Features of the vital activity of cereal aphids in the North-West of Russia

The publication presents data on long-term monitoring of the dynamics of the number of cereal aphids on spring grain crops in the Pushkinsky district of St. Petersburg and the Tosnensky district of the Leningrad region. The appearance of winged parthenogenetic females in the fields in the biotope of grain crops was noted in the first decade of June, the maximum number of aphids - in the second decade. Over the years of observations, outbreaks of mass reproduction were in 1999, 2002, and 2021. The analysis is carried out of the dependence of the number of aphids Rh. padi on the weather conditions of the region. The correlation between the number of aphids on wheat plants and the average monthly April air temperatures was low (r= 0.31), it was higher between the number of insects and the June average monthly air temperatures (r=0.57). At the same time, the average monthly air temperature in April and June 1999 and 2002 were higher than the average long-term indicators. This indicator turned out to be the most effective between the sum of effective temperatures for the spring-summer period (April May, June) and the number of aphids (r= 0.77). The correlation coefficient between the amount of precipitation during this period and, accordingly, the number of aphids turned out to be negative (– 0.6). It is assumed that the degree of pest population of plants in the summer period depends on the number of eggs laid by oviparous females in the previous autumn. In our studies, the correlation coefficient between these indicators was 0.52. One of the most important entomophages of cereal aphids is the beetle Coccinella septempunctata L. Over the years of observations, the number of predators varied from 0.2 to 5 individuals per 1 model site. During the years of mass reproduction of aphids in 2002 and 2021, the number of coccinellids per model site was low and equal to 0.2-0.5. The large grass aphid Sitobion avenae F. appears in the fields of the region in early July. The largest number of species was recorded in 2016, 2020,2022. In the experiments of 2022, the insect preferred spring wheat and oats, compared with barley.

Threshold dynamics and probability density functions of a stochastic predator–prey model with general distributed delay

Predator–prey interactions are among the most complicated interactions between biological species, in which there may be both delay digestion and stochastic fluctuation. In the literature, due to the computational complexity and the lack of available methods, few papers have directly considered the predator–prey model for the combination of general infinite time delays with stochasticity. In this sense, this work is devoted to studying the long-term qualitative behavior of a stochastic predator–prey system with general infinite distributed delay. First, we establish sufficient and necessary conditions for exponential extinction and persistence of species. Notably, not only do our results cover the predator–prey model without stochastic noises and time delays, but also reveal the impact of environmental noises on population dynamics. Moreover, there are some challenges to analyze the stationary distribution of the numbers of prey and predator under species persistence. Based on the recent work (Zhou et al., 2020) where the density function of a three-dimensional avian influenza model with non-degenerate diffusion is concerned, we further generalize the relevant theories to a five-dimensional population system with degenerate diffusion. Via solving the corresponding Fokker–Planck equations, several approximate expressions of the density function of the stochastic predator–prey system with special distribution delay kernels are obtained. Finally, we provide some numerical simulations to supplement the analytical results and study the impact of stochastic noises.

High order sliding mode control for restoration of a population of predators in a Lotka-Volterra system.

Human-induced extinction and rapid ecological changes require the development of techniques that can help avoid extinction of endangered species. The most used strategy to avoid extinction is reintroduction of the endangered species, but only 31% of these attempts are successful and they require up to 15 years for their results to be evaluated. In this research, we propose a novel strategy that improves the chances of survival of endangered predators, like lynx, by controlling only the availability of prey. To simulate the prey-predator relationship we used a Lotka-Volterra model to analyze the effects of varying prey availability on the size of the predator population. We calculate the number of prey necessary to support the predator population using a high-order sliding mode control (HOSMC) that maintains the predator population at the desired level. In the wild, nature introduces significant and complex uncertainties that affect species' survival. This complexity suggests that HOSMC is a good choice of controller because it is robust to variability and does not require prior knowledge of system parameters. These parameters can also be time varying. The output measurement required by the HOSMC is the number of predators. It can be obtained using continuous monitoring of environmental DNA that measures the number of lynxes and prey in a specific geographic area. The controller efficiency in the presence of these parametric uncertainties was demonstrated with a numerical simulation, where random perturbations were forced in all four model parameters at each simulation step, and the controller provides the specific prey input that will maintain the predator population. The simulation demonstrates how HOSMC can increase and maintain an endangered population (lynx) in just 21-26 months by regulating the food supply (hares), with an acceptable maximal steady-state error of 3%.

What constrains food webs? A maximum entropy framework for predicting their structure with minimal biases.

Food webs are complex ecological networks whose structure is both ecologically and statistically constrained, with many network properties being correlated with each other. Despite the recognition of these invariable relationships in food webs, the use of the principle of maximum entropy (MaxEnt) in network ecology is still rare. This is surprising considering that MaxEnt is a statistical tool precisely designed for understanding and predicting many types of constrained systems. This principle asserts that the least-biased probability distribution of a system's property, constrained by prior knowledge about that system, is the one with maximum information entropy. MaxEnt has been proven useful in many ecological modeling problems, but its application in food webs and other ecological networks is limited. Here we show how MaxEnt can be used to derive many food-web properties both analytically and heuristically. First, we show how the joint degree distribution (the joint probability distribution of the numbers of prey and predators for each species in the network) can be derived analytically using the number of species and the number of interactions in food webs. Second, we present a heuristic and flexible approach of finding a network's adjacency matrix (the network's representation in matrix format) based on simulated annealing and SVD entropy. We built two heuristic models using the connectance and the joint degree sequence as statistical constraints, respectively. We compared both models' predictions against corresponding null and neutral models commonly used in network ecology using open access data of terrestrial and aquatic food webs sampled globally (N = 257). We found that the heuristic model constrained by the joint degree sequence was a good predictor of many measures of food-web structure, especially the nestedness and motifs distribution. Specifically, our results suggest that the structure of terrestrial and aquatic food webs is mainly driven by their joint degree distribution.

A predator breeding station for augmentative biological control of scolytine crop pests

The square-necked grain beetle, Cathartus quadricollis (Coleoptera: Silvanidae), is a predator of two significant crop pests in Hawaii: the coffee berry borer, Hypothenemus hampei, in coffee and the tropical nut borer, H. obscurus (Coleoptera: Curculionidae: Scolytinae) in macadamia nut. C. quadricollis is also a stored grain pest and is known to respond to its aggregation pheromone (i.e., quadrilure). Field tests were conducted in a macadamia nut orchard using sticky traps to identify the best lure dispenser and trap color based on captures of adult C. quadricollis. When quadrilure was released in different dispenser types, in combination with a fungal volatile blend released from a pouch, we found that a membrane-type quadrilure release dispenser (wafer) was superior to a red septa, gray septa, or open vial dispenser in attracting C. quadricollis. In subsequent tests, the combination of a quadrilure lure and a lure releasing a blend of fungal volatiles caught more C. quadricollis than the quadrilure lure alone. Also, we found that black sticky traps caught more C. quadricollis than did blue, green, red, yellow, white, or clear sticky traps. A predator breeding station consisting of a screened and sheltered enclosure containing food (250 g of cracked corn: cornmeal [4:1, w:w] mix) and the membrane-type quadrilure lure was developed to augment predator numbers in coffee and macadamia fields. In the laboratory, stocking a breeding station with 100 C. quadricollis resulted in production and dispersal of about 10,000 adults per station over a four-month period at 25 °C. In field tests, use of the quadrilure lure plus a fungal volatiles lure or the quadrilure lure alone were placed in breeding stations in a coffee field to attract naturally occurring wild adults for a five-week period, then returned to the laboratory where they both produced roughly 3,000 adults per station over a five-month period. The predator breeding station was an efficient way to multiply C. quadricollis numbers in the field and could be used to augment biological control of the coffee berry borer in coffee and tropical nut borer in macadamia nut.

Emergence of the subtropical sea urchin Centrostephanus rodgersii as a threat to kelp forest ecosystems in northern New Zealand

Marine protected areas have long been proposed as a key tool to restore lost food web interactions and increase the resilience of ecosystems to climate change impacts. However, a changing climate can result in the arrival of new species or differentially affect native species, which can alter ecosystem dynamics and make it difficult to predict how ecosystems will respond to protection. The long-spined sea urchin Centrostephanus rodgersii is a well-known range extender with large impacts on kelp forest ecosystems, yet its response to warming and long-term marine protection has not been examined within its native range. We examine long-term trends in C. rodgersii and the endemic sea urchin Evechinus chloroticus following no-take protection within the Poor Knights Islands Marine Reserve, in northeastern Aotearoa New Zealand, from 1999-2022, and compare with population trends at an unprotected island group. Within the marine reserve, E. chloroticus decreased in density, became more cryptic, and urchin barrens associated with this species largely disappeared, whereas in fished areas, populations and extent of barrens remained stable. This differing response between the reserve and fished location is consistent with a top-down effect and greater abundance of predatory fish in the reserve. In contrast, the subtropical sea urchin C. rodgersii increased in abundance by 9.3 times in the Poor Knights Island Marine Reserve and 4.3 times at the fished location, with areas of urchin barrens associated with this species developing at both locations. This increase coincides with substantial warming over the monitoring period (0.25°C decade-1) and low numbers of key predators (rock lobster) at both reserve and fished locations. This highlights the emerging threat of C. rodgersii to rocky reefs in the region and how marine protection alone may not increase resilience to this threat. This suggests multifaceted management approaches are needed to mitigate the impacts of emerging pest species and increase the resilience of temperate reef ecosystems in a warming climate.

Effects of prey refuge and predator cooperation on a predator–prey system

ABSTRACT We develop and investigate a discrete-time predator–prey model with cooperative hunting among predators and a spatial prey refuge. The system can exhibit two positive equilibria if the magnitude of cooperation is large and the maximal reproduction number of predators is less than one. In such a scenario, the predator population may exhibit a strong Allee effect, and therefore the predator may survive if its density is above the threshold. When the positive equilibrium is unique, we prove that hunting cooperation can destabilize the equilibrium through a Neimark–Sacker bifurcation. Numerical findings indicate that a high degree of predator hunting cooperation can help rescue the predator population if the proportion of prey refuge is large, while hunting cooperation becomes destabilizing when the proportion of refuge is small. Despite hunting cooperation's destabilizing effect, it can facilitate predator persistence, particularly with a large proportion of prey refuge. Furthermore, there exists a wide parameter space where the predator–prey interaction may exhibit chaotic behaviour.

Іле өзенінің жайылмасында кездесетін жыртқыш аңдардың (Carnivora: Canidae, Mustelidae) сапалық құрамы мен орналасу ерекшеліктері

The article presents for the first time new data on habitats, shelters and the dynamics of the number of 6 species of predators found in the floodplain of the Ile River and adjacent territories in the spring and summer months (during the breeding season) in 2007-2019, 2022. The research was carried out using classical methods of theriological science. These predators can be divided into 2 groups: 1-sedentary and 2-nomads. The first group includes 3 species (jackal, fox, badger), and the second group includes 3 species (wolf, dressing, weasel). The share of predators in the use of biotopes is different: 3 species in floodplains of rivers (jackal, fox, badger), 1 species among reeds on islands (jackal), 3 species in fortified hilly sands (wolf, fox, bandaging), one species in open steppes of rare vegetation (weasel), 4 species in rocky-rocky places (wolf, fox, badger, weasel) and in localities there are 2 species (jackal, weasel). By the nature of the use of shelters, predators are divided into lairs, burrows and "freeloaders" (occupying other people's burrows). Lairs include one species (wolf), burrowers 3 species (jackal, fox, badger), 2 species (dressing, weasel) occupy other people's burrows. The number of predators fluctuated between 2017 and 2019 under the influence of various factors (food supply, excessive anxiety, poaching). During these years, on a 10-kilometer route (only 90 km), the average number of wolves was 0.33 individuals, jackals – 5.3, foxes-3.7, badgers-2, bandages -0.67 and weasels -1.0 individuals.

Landscapes of nausea: Successful conditioned taste aversion in a wild red fox population

AbstractPredation by invasive mammalian species is one of the key drivers of native species' population declines and extinctions. Current management of invasive species focuses on their removal from the landscape. However, total removal can be difficult, costly and even impossible. If eradication is not achieved, reductions in predator numbers are often temporary. New tactics are needed to target predators in situ, to reduce their negative impacts. We test the efficacy of conditioned taste aversion (CTA), a tactic that could reduce the impact of predation on target prey species. By associating nausea with a specific food source, it may be possible to condition an aversion to a target bait, and ultimately to live animals in the wild. To assess if wild invasive red foxes (Vulpes vulpes) can be conditioned to avoid a specific food source, we used baits (fried deboned chicken) containing encapsulated levamisole, an anthelmintic agent known to induce nausea leading to emesis and/or diarrhea at high dosages with no long‐term side effects. We buried baits at 30 stations across an open landscape. After treatment, reductions in control baits taken (at least 30%) were observed for 68 days, indicating the use of CTA had successfully reduced bait consumption by red foxes in a wild context. To our knowledge, this study represents the first successful test of CTA to a meat bait in a wild red fox population. Our results suggest that CTA shows promise as a tool to reduce the predation of vulnerable animals providing an alternative tactic to manage the impacts of invasive mammalian predators where eradication is currently impossible.

Big value of a small natural monument of regional signifi cance Mys Devich’y Peski (Primorsky Krai, Russia)

This is the fi rst biota description of the regional nature monument Mys Devich’y Peski, located on the west coast of Lake Khanka (Primorsky Krai, Russia). The Amur softshell turtle Pelodiscus maackii (Brandt, 1857) and a large bivalve mollusk Lanceolaria chankensis Moskvicheva, 1973, listed in the Red Book of the Russian Federation, inhabit the coastal waters, while Oxytropis chankaensis Jurtz., a coastal endemic of Lake Khanka, grows on the sandy beaches. This natural monument is one of the few places of successful breeding of the Amur softshell turtle after the catastrophic rise of water in the lake. The local group of P. maackii is dominated by mature individuals of medium size with a track width of 190–229 mm. Average number of tracks of these reptiles per 1 km of coastline is 38.2, maximum is 60 (n = 109). We have noted a high number of predators – raccoon dogs Nyctereutes procyonoides (Gray, 1834) and otters Lutra lutra Linnaeus, 1758, ravaging turtle clutches.The geographical location of the Mys Devich’y Peski natural monument should be clarifi ed in its cadastral case, and the monument should be assigned with a zoological profi le.

Wildflower plantings have mixed effects on insect herbivores and their natural enemies

Flower strips are advocated as a strategy to promote beneficial insects as well as the services they deliver to adjacent crops. Flower strips have, however, often been developed separately for pollinators and natural enemies and, additionally, little consideration has been given to effects on insect herbivores. We sampled insect herbivores, their natural enemies and parasitism of pest eggs using vacuum sampling, sticky cards and egg cards in nine pairs of bee-attractive wildflower plantings and control field borders, as well as in adjacent tomato and watermelon crop fields in Yolo County, California 2015–2016. Control field borders had a higher total number of herbivores on sticky traps than did wildflower plantings, a pattern that was driven by more aphids, hoppers, psyllids and whiteflies, whereas wildflower plantings had more lace bugs and Lygus bugs. The total number of herbivores in the adjacent crop fields did not differ between treatments, but there were more leaf beetles near (at 10 m but not 50 m from) wildflower plantings. Control field borders had a higher total number of predators, driven by more big-eyed bugs, lady beetles and minute pirate bugs, whereas spiders were more common in wildflower plantings. The total number of predators in adjacent crop fields was, however, higher in those next to wildflower plantings, which was driven by more minute pirate bugs. Parasitoid wasps were more common in wildflower plantings and at 10 m but not 50 m into adjacent crop fields. Stink bug egg parasitism rate did not differ between treatments, either in the borders or in the crop fields. In conclusion, wildflower plantings clearly affect the insect herbivore and natural enemy community, but do so in a highly taxon-specific manner, which can lead to both positive and negative outcomes for pest control as a result.

Spatio-Temporal Patterns of Livestock Predation by Leopards in Bardia National Park, Nepal

Human–wildlife conflict is a challenging issue that requires the attention of conservationists worldwide. Habitat fragmentation and encroachment reduce the abundance of prey species, and an increase in the number of predators leads to a higher risk of conflict with large cats such as leopards, jeopardizing conservation efforts. This study explored the spatio-temporal pattern of the human–leopard conflict in Bardia National Park, Nepal, from 2000 to 2020. To analyze the conflict with leopards, we used data (compensation cases filed in the park) from the buffer zone management office, the National Trust for Nature Conservation (NTNC), and the Department of National Park and Wildlife Conservation (DNPWC). Leopard attacks on livestock are increasing exponentially, with 3335 livestock killed in 2652 attacks occurring during the study period. Although livestock depredation by leopards occurred all over the park, the southern cluster has most documented livestock damage (64.01%). The eastern and northern clusters reported fluctuating and dispersed predation events, respectively. Our spatial analysis indicated no effect of topography (slope) on livestock depredation by leopards. We recorded the highest number of leopard attacks and predation during the dry winter season when the nights are longer and livestock remain in their sheds. This carnivore mostly limited its prey to small-sized livestock (95.77%) such as goats, sheep, and pigs, whereas attacks on large-sized (cow and buffalo) livestock were least frequent. Among small-sized livestock, goats are the most predated (66.92%), followed by pigs (20.30%), in all seasons. The escalating human–leopard conflict in BNP is thus a severe threat to conservation efforts as the park has already invested a substantial amount of money (approx. USD 80,000) compensating for livestock lost in leopard attacks over the last two decades. Improving habitat conditions to reduce competition inside the park, developing an insurance scheme for livestock and humans, providing support for upgraded sheds, and the development of practical and feasible strategies that focus on specific animals and clusters of the national park are needed to reduce conflicts to maintain the co-existence between wildlife and human beings.