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1.
J Econ Entomol ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38986518

RESUMO

The western corn rootworm, (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae), is a serious pest of corn (Zea mays Linnaeus, Cyperales: Poaceae) in the midwestern United States. Management practices for corn rootworm larvae include crop rotation, transgenic corn producing insecticidal toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt), and soil-applied insecticides. The extent to which combining soil-applied insecticide with Bt corn would be beneficial from the perspective of insect resistance management (IRM) or integrated pest management (IPM) remains uncertain. We conducted a 3-yr field study to characterize the implications of combining a soil-applied insecticide and Bt corn for IRM and IPM of western corn rootworm. Experimental treatments were Bt corn, a soil-applied insecticide, the combination of these factors, and an experimental control in which both factors were absent. Data were collected on root injury to corn by rootworm, survival to adulthood, adult size, and emergence time for western corn rootworm. We found that mortality caused by the soil-applied insecticide was insufficient to delay resistance to Bt corn. While combining Bt corn and a soil-applied insecticide may provide a short-term economic benefit, additional research is needed to determine appropriate economic thresholds for combining these tactics. Additionally, combining a soil-applied insecticide and Bt corn would not be sustainable over multiple growing seasons because of its potential to rapidly select for Bt resistance. In general, a more sustainable IRM strategy for rootworm management would include using crop rotation and alternating between non-Bt corn with soil-applied insecticide and Bt corn without soil-applied insecticide.

2.
Behav Processes ; : 105079, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39025319

RESUMO

This study investigated the influence of group size (individual, groups of five, and 20) on the response of common minnow to visual cues created by vertical black and white stripes over time. The stripes were displayed on a monitor either at one end of an experimental tank, while the other was uniform white, or both ends simultaneously. Reponses were compared with a control (stripes absent). Visual cues were pseudo-randomly presented every 15-minutes over six-hours. Three predictions were made: first, due to more efficient flow of information, larger groups would respond more rapidly (Rate of response) to the visual cues. Second, assuming visual cues provide a proxy for structure and larger groups experience greater benefits of group membership due to reduced predatory risk, there will be stronger association (Strength of association and Final association) with stripes for individuals and smaller groups compared with larger groups. Consequently, the association with visual cues exhibited by larger groups would diminish over time compared to smaller, more risk averse groups. As expected, larger groups exhibited a faster Rate of response to visual cues, and individual fish a greater Strength of association compared with the largest group size. Final association, however, was more common for larger groups compared to both smaller groups and individuals. Contrary to the final prediction, responses to visual cues did not decrease over time for any group size, suggesting innate behaviour or an experimental duration insufficient to observe habituation.

3.
Pest Manag Sci ; 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38940546

RESUMO

BACKGROUND: Transgenic Bt technology in soybean, with plants expressing Cry1Ac, has been adopted as an insect pest management tool. It was first adopted in large areas of South America and Asia in 2013. The risk of resistance in target pests to this technology demands insect resistance management (IRM) programs. In Brazil, a structured refuge (area of non-Bt soybean) planted adjacent to the Bt soybean crop has been an important IRM recommendation, particularly for the primary lepidopteran defoliators Anticarsia gemmatalis (Lepidoptera: Erebidae) and Chrysodeixis includens (Lepidoptera: Noctuidae). The overall goal of this study was to validate IRM recommendations to Bt soybean. The objectives were to document the impact of soybean phenology, cultivar choice and non-Bt soybean defoliation on moth oviposition. In addition, a mark-release-recapture study estimated the dispersal capacity of these species. Five field experiments per species were performed for 3 years. RESULTS: Our results revealed an increase in A. gemmatalis and C. includens oviposition, respectively, on Bt plants as a consequence of the difference in plant growth stage at the time of oviposition. Defoliation of non-Bt plants significantly increased the oviposition preference of both moth species for Bt plants. The mark-release-recapture experiment indicated an average dispersal distance of ~300 m from the release point for A. gemmatalis, with maximum recapture at 1000 m. CONCLUSION: Overall, our findings emphasize the importance of planting synchronization of Bt soybean and the structured refuge. In addition, when operational aspects in large soybean areas challenge this recommendation, the priority should be for planting the refuge area first. This approach will minimize the impact of selective oviposition of A. gemmatalis and C. includens. © 2024 Society of Chemical Industry.

4.
BMC Ophthalmol ; 24(1): 273, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38943095

RESUMO

BACKGROUND: Glaucoma is a worldwide eye disease that can cause irreversible vision loss. Early detection of glaucoma is important to reduce vision loss, and retinal fundus image examination is one of the most commonly used solutions for glaucoma diagnosis due to its low cost. Clinically, the cup-disc ratio of fundus images is an important indicator for glaucoma diagnosis. In recent years, there have been an increasing number of algorithms for segmentation and recognition of the optic disc (OD) and optic cup (OC), but these algorithms generally have poor universality, segmentation performance, and segmentation accuracy. METHODS: By improving the YOLOv8 algorithm for segmentation of OD and OC. Firstly, a set of algorithms was designed to adapt the REFUGE dataset's result images to the input format of the YOLOv8 algorithm. Secondly, in order to improve segmentation performance, the network structure of YOLOv8 was improved, including adding a ROI (Region of Interest) module, modifying the bounding box regression loss function from CIOU to Focal-EIoU. Finally, by training and testing the REFUGE dataset, the improved YOLOv8 algorithm was evaluated. RESULTS: The experimental results show that the improved YOLOv8 algorithm achieves good segmentation performance on the REFUGE dataset. In the OD and OC segmentation tests, the F1 score is 0.999. CONCLUSIONS: We improved the YOLOv8 algorithm and applied the improved model to the segmentation task of OD and OC in fundus images. The results show that our improved model is far superior to the mainstream U-Net model in terms of training speed, segmentation performance, and segmentation accuracy.


Assuntos
Algoritmos , Fundo de Olho , Glaucoma , Disco Óptico , Disco Óptico/diagnóstico por imagem , Humanos , Glaucoma/diagnóstico
5.
J Environ Manage ; 363: 121408, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38852411

RESUMO

With the intensification of climate change, incorporating climate information into protected areas planning has become crucial in reducing biodiversity loss. However, the current natural reserve system in China does not take climate information into account. Therefore, we assessed the effectiveness of existing protected areas through climate refuge and connectivity rankings, and Zonation software was used to identify the ecological priority zone in China by combining climate indicators and human footprint. The results show that the current natural protected areas in China have certain limitations in dealing with climate change, and some protected areas may struggle to maintain their value in biodiversity conservation under climate change. Moreover, China still has lots of important areas that can maintain biodiversity under climate change, but most of them are not covered by protected areas. The results provide support for the planning of China's nature protected area system in response to climate change.


Assuntos
Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais , China
6.
Sci Total Environ ; 945: 174050, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-38906290

RESUMO

Anthelmintic residues in livestock dung can adversely affect beneficial organisms. Targeted selective treatment (TST) of a reduced proportion of livestock with anthelmintics can slow resistance development in gastrointestinal nematodes by providing residue-free dung which could also benefit non-target organisms. We tested effects of TST on survival and reproduction of the dung beetle Onthophagus taurus (Scarabaeidae) in a factorial glasshouse experiment (Experimental treatments: five TST levels, 0.00, 0.25, 0.50, 0.75, 1.00 x four ivermectin concentrations, 125, 250, 375, 500 ppb). Each mesocosm comprised a 60 L bin containing sand, four dung pats and six pairs of adult beetles (F0 generation). No effects of TST level and ivermectin concentration on mortality of F0 adults after one week were observed. F0 adult brood ball production was affected by TST level, particularly at high ivermectin concentrations. Brood ball production increased as more untreated pats became available, with greater increases at higher ivermectin concentrations. We tested for evidence of a reported attraction of dung beetles to ivermectin-treated dung using a novel glitter-marker to trace the origin of dung used in brood balls. Where mesocosms contained both dung types, the proportion of brood balls created from untreated dung showed no statistical difference from the null expectation based on untreated dung availability in the mesocosm. Emergence of F1 adults was affected by the increase in TST, with this effect dependent on concentration. Treatments with concentrations of 250-500 ppb had the lowest emergence rates (ca. 5-20 % in mesocosms where all dung pats were treated) but emergence rates increased with TST level, reaching 68-88 % emergence where no dung pats were treated with ivermectin. Ivermectin-induced mortality occurred predominantly at egg and first instar stages. TST can provide refuges for dung beetles offering a strategy for livestock producers to maintain livestock welfare whilst benefiting from ecosystem services provided by important insects.


Assuntos
Besouros , Fezes , Ivermectina , Gado , Animais , Besouros/efeitos dos fármacos , Fezes/parasitologia , Fezes/química , Anti-Helmínticos/uso terapêutico
7.
J Econ Entomol ; 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38832396

RESUMO

Corn, Zea mays L. (Poales: Poaceae), growers in the US Cotton Belt are required to plant 20% of total corn acres to non-Bt hybrids for resistance management (non-Bt refuge). Most growers do not meet this requirement, in part, because they perceive non-Bt hybrids to yield less than Bt hybrids. We planted multiple non-Bt and Bt hybrids from a single company in small-plot replicated trials at a single location from 2019 to 2023, as well as in small-plot replicated trials at multiple locations during 2022 and 2023. In the single location, we measured kernel injury from corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and we recorded yield at all locations. In the single location trial, yields only separated among hybrids in 3 out of 5 years. In the multiple location trial, yields were variable between both years. We found that Bt hybrids tended to yield higher than non-Bt hybrids overall, but this was influenced by the inclusion of non-Bt hybrids that had a lower overall genetic yield potential in the environments we tested them in. In both tests, when hybrids were analyzed during each year, both Bt and non-Bt hybrids were among the statistically highest yielders. Our study demonstrates the importance of comparing multiple Bt and non-Bt hybrids to draw yield comparisons. This highlights the need for corn seed company breeders to put effort into improving yield for non-Bt hybrids. Hopefully this effort will translate into increased planting of non-Bt refuge corn for growers in the US Cotton Belt.

8.
Geohealth ; 8(6): e2023GH000985, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38912226

RESUMO

The urban heat island effect exacerbates independent climate change-induced shifts toward longer, stronger, and more frequent heat extremes. Environmental inequity, driven by a history of racially motivated urban planning policies, has led particular demographics to bear the worst impacts of urban heat exposure and thus also climate change. These impacts cause adverse health outcomes in the form of heat emergencies. Through a novel demographic and spatial analysis of heat-related illness Emergency Medical Services data from Richmond, Virginia, this study investigates the relationships between heat health emergencies and intra-urban heat islands quantified through three heat exposure metrics. We also evaluate the accessibility of built refuge from urban heat in the form of public transit infrastructure, libraries, and government cooling centers in relation to these emergencies. We found that heat emergencies are inequitably distributed among racial, age, and socioeconomic groups in Richmond, particularly among residents identified as Male, Black or African American, 50+ years old, and experiencing mental health, intoxication, and/or homelessness. We found significant associations between the location of these heat emergencies and urban heat islands as estimated from remotely-sensed surface and community science-derived air temperature metrics, but not a co-estimated heat index. We also found that available refuge facilities are insufficiently located to protect individuals with reduced mobility across areas with the highest number of heat-related health emergencies. Community involvement in the mitigation and management of extreme heat threats, especially for those disproportionately impacted, is necessary to decrease the number of summertime heat illnesses.

9.
Ecol Evol ; 14(6): e11608, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38919644

RESUMO

Genetic diversity can modulate a population's response to a changing environment and plays a critical role in its ecological function. While multiple processes act to maintain genetic diversity, sexual reproduction remains the primary driving force. Eelgrass (Zostera marina) is an important habitat-forming species found in temperate coastal ecosystems across the globe. Recent increases in sea surface temperatures have resulted in shifts to a mixed-annual life-history strategy (i.e., displaying characteristics of both annual and perennial meadows) at its southern edge-of-range. Given that mating systems are intimately linked to standing levels of genetic variation, understanding the scope of sexual reproduction can illuminate the processes that shape genetic diversity. To characterize edge-of-range eelgrass mating systems, developing seeds on flowering Z. marina shoots were genotyped from three meadows in Topsail, North Carolina. In all meadows, levels of multiple mating were high, with shoots pollinated by an average of eight sires (range: 3-16). The number of fertilized seeds (i.e., reproductive success) varied significantly across sires (range: 1-25) and was positively correlated with both individual heterozygosity and self-fertilization. Outcrossing rates were high (approx. 70%) and varied across spathes. No clones were detected, and kinship among sampled flowering shoots was low, supporting observed patterns of reproductive output. Given the role that genetic diversity plays in enhancing resistance to and resilience from ecological disturbance, disentangling the links between life history, sexual reproduction, and genetic variation will aid in informing the management and conservation of this key foundation species.

10.
J Insect Sci ; 24(3)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38703099

RESUMO

This study was carried out in 3 types of biotopes where vegetable crops are not grown to highlight their contribution to the dynamics of vegetable-infesting flies. To this end, a trapping system based on a sexual attractant, the Cuelure associated with an insecticide was set up in 18 biotopes (6 natural areas, 6 mango orchards, and 6 agroforestry parks) in the regions of Hauts Bassins and Cascades in the South-West of Burkina Faso. During the trapping monitoring, which was done every 2 wk to collect insects captured, fruits present in 3 types of biotopes were sampled and incubated for insect emergence. Ten Dacus (Fabricius) [Diptera: Tephritidae] species and Zeugodacus cucurbitae (Coquillett) [Diptera: Tephritidae] were trapped in the study area. The predominant species captured was Z. cucurbitae (52.93%) followed by Dacus punctatifrons (Karsch) [Diptera: Tephritidae] (29.89%) and Dacus humeralis (Bezzi) (12.71%). Six tephritid species were emerged from 6 wild fruit species belonging to Cucurbitaceae, Apocynaceae, and Passifloraceae families. Fruit flies were more abundant from Jul to Nov with peaks observed in Aug or Oct depending on the species. Citrullus colocynthis L. (Cucurbitaceae), Lagenaria sp. (Cucurbitaceae), Passiflora foetida L. (Passifloraceae), and Passiflora sp. acted as reservoir host plants of Dacus ciliatus (Loew), Dacus bivittatus (Bigot), Dacus vertebratus (Bezzi) [Diptera: Tephritidae], D. punctatifrons, and Z. cucurbitae, the major vegetable insect pests in West Africa. The 3 types of biotopes acted as suitable refuge areas of vegetable crop-infesting fruit flies either for the favorable microclimate or for the alternative host plants.


Assuntos
Estações do Ano , Tephritidae , Animais , Tephritidae/fisiologia , Tephritidae/crescimento & desenvolvimento , Burkina Faso , Produtos Agrícolas/crescimento & desenvolvimento , Verduras/crescimento & desenvolvimento , Dinâmica Populacional , Frutas
12.
J Econ Entomol ; 117(3): 1106-1112, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38603568

RESUMO

Transgenic crops producing Bacillus thuringiensis (Bt) toxins are commonly used for controlling insect pests. Nearby refuges of non-Bt host plants play a central role in delaying the evolution of resistance to Bt toxins by pests. Pervasive fitness costs associated with resistance, which entail lower fitness of resistant than susceptible individuals in refuges, can increase the ability of refuges to delay resistance. Moreover, these costs are affected by environmental factors such as host plant suitability, implying that manipulating refuge plant suitability could improve the success of the refuge strategy. Based on results from a previous study of Trichoplusia ni resistant to Bt sprays, it was proposed that low-suitability host plants could magnify costs. To test this hypothesis, we investigated the association between host plant suitability and fitness costs for 80 observations from 30 cases reported in 18 studies of 8 pest species from 5 countries. Consistent with the hypothesis, the association between plant suitability and fitness cost was negative. With plant suitability scaled to range from 0 (low) to 1 (high), the expected cost was 20.7% with a suitability of 1 and the fitness cost increased 2.5% for each 0.1 decrease in suitability. The most common type of resistance to Bt toxins involves mutations affecting a few types of midgut proteins to which Bt toxins bind to kill insects. A better understanding of how such mutations interact with host plant suitability to generate fitness costs could be useful for enhancing the refuge strategy and sustaining the efficacy of Bt crops.


Assuntos
Toxinas de Bacillus thuringiensis , Bacillus thuringiensis , Aptidão Genética , Resistência a Inseticidas , Mariposas , Animais , Resistência a Inseticidas/genética , Mariposas/crescimento & desenvolvimento , Mariposas/genética , Mariposas/fisiologia , Plantas Geneticamente Modificadas , Endotoxinas , Proteínas Hemolisinas , Controle Biológico de Vetores , Proteínas de Bactérias , Produtos Agrícolas
13.
Sci Rep ; 14(1): 9006, 2024 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-38637581

RESUMO

Marine heatwaves are increasing in frequency and duration, threatening tropical reef ecosystems through intensified coral bleaching events. We examined a strikingly variable spatial pattern of bleaching in Moorea, French Polynesia following a heatwave that lasted from November 2018 to July 2019. In July 2019, four months after the onset of bleaching, we surveyed > 5000 individual colonies of the two dominant coral genera, Pocillopora and Acropora, at 10 m and 17 m water depths, at six forereef sites around the island where temperature was measured. We found severe bleaching increased with colony size for both coral genera, but Acropora bleached more severely than Pocillopora overall. Acropora bleached more at 10 m than 17 m, likely due to higher light availability at 10 m compared to 17 m, or greater daily temperature fluctuation at depth. Bleaching in Pocillopora corals did not differ with depth but instead varied with the interaction of colony size and Accumulated Heat Stress (AHS), in that larger colonies (> 30 cm) were more sensitive to AHS than mid-size (10-29 cm) or small colonies (5-9 cm). Our findings provide insight into complex interactions among coral taxa, colony size, and water depth that produce high spatial variation in bleaching and related coral mortality.


Assuntos
Antozoários , Animais , Recifes de Corais , Ecossistema , Água , Temperatura
14.
Ecol Evol ; 14(4): e11191, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38571792

RESUMO

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator-prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide.

15.
J Therm Biol ; 121: 103841, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38552446

RESUMO

Environmental temperatures are increasing worldwide, threatening desert ectotherms already living at their thermal limits. Organisms with flexible thermoregulatory behaviours may be able to mitigate the effects of extreme temperatures by moving among microhabitats, yet little work has tracked movement patterns of desert ectotherms in the wild over diurnal scales or compared behaviour among seasons. Here, we used camera traps to track the thermoregulatory behaviour and microhabitat choices of 30 desert lizards (Messalina bahaldini) in custom, outdoor arenas that provided access to open, rock, and bush microhabitats. We found that in the summer, lizards preferred to move to the shaded microhabitats and remain there under warmer conditions. During winter, however, lizards' activity was not related to temperature, and lizards mostly chose to remain in the open habitat. Interestingly, in both seasons, lizards tended to remain in their current microhabitat and moved infrequently between certain combinations of microhabitats. Our study shows that thermoregulation (shade-seeking behaviour) is a major factor during summer, helping lizards to avoid extreme temperatures, but not during winter, and shows a novel effect of current microhabitat on movement, suggesting that other biotic or abiotic factors may also drive microhabitat choice. Understanding the complex factors at play in microhabitat choice is critical for developing conservation programs that effectively mitigate the negative impacts of climate change on desert animals.


Assuntos
Regulação da Temperatura Corporal , Clima Desértico , Lagartos , Estações do Ano , Animais , Lagartos/fisiologia , Ecossistema , Comportamento Animal , Movimento , Masculino
16.
Biol Lett ; 20(3): 20230285, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38471565

RESUMO

For prey, taking refuge from predators has obvious fitness benefits but may also be costly by impinging on time and effort available for feeding or attracting mates. The antipredator responses of refuge-seeking animals are therefore predicted to vary strategically depending on how threatening they perceive the risk. To test this, we studied the impacts of a simulated predatory threat on the antipredator responses of wild sandy prawn-gobies (Ctenogobiops feroculus) that co-inhabit burrows with Alpheus shrimp (family Alpheidae) in a mutualistic relationship. We exposed goby-shrimp pairs, repeatedly on three separate occasions, to an approaching threat and measured the antipredator behaviours of both partners. We found that re-emerging from the burrow took longer in large compared to small fish. Moreover, quicker re-emergence by small-but not medium or large-sized gobies-was associated with an earlier flight from the approaching threat (i.e. when the threat was still further away). Finally, the goby and shrimp sharing a burrow were matched in body size and their risk-taking behaviour was highly dependent on one another. The findings contribute to our understanding of how an individual's phenotype and perception of danger relates to its risk-taking strategy, and how mutualistic partners can have similar risk sensitivities.


Assuntos
Decápodes , Perciformes , Animais , Simbiose , Peixes/fisiologia , Decápodes/fisiologia , Comportamento Predatório
17.
Child Adolesc Psychiatry Ment Health ; 18(1): 42, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38553764

RESUMO

BACKGROUND: With Russia's invasion of the Ukraine on February 2022, Ukrainian children and adolescents have been exposed to several stressful life events. In addition to the confrontation with war, flight and parent-child separation due to flight and forced displacement, the majority underwent another challenge at the initial phase of the war: the fatherly separation due to conscription. MAIN BODY: In the literature, the negative effects of exposure to war and flight/refuge, parent-child separation due to flight or forced displacement and parental deployment are well established. In the context of self-experienced war, the effects of parent-child separation caused by compulsory military service have not yet been sufficiently taken into account. However, the findings of the literature on the impact of these events on the mental health of children and adolescents show that they are at high risk for developing numerous psychological and behavioral problems. CONCLUSION: As children's and adolescents' mental health might be severely affected by war and its consequences, interventional programs that address the special needs of those children and adolescents are crucial.

18.
Math Biosci Eng ; 21(3): 4554-4586, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38549340

RESUMO

The refuge effect is critical in ecosystems for stabilizing predator-prey interactions. The purpose of this research was to investigate the complexities of a discrete-time predator-prey system with a refuge effect. The analysis investigated the presence and stability of fixed points, as well as period-doubling and Neimark-Sacker (NS) bifurcations. The bifurcating and fluctuating behavior of the system was controlled via feedback and hybrid control methods. In addition, numerical simulations were performed as evidence to back up our theoretical findings. According to our findings, maintaining an optimal level of refuge availability was critical for predator and prey population cohabitation and stability.


Assuntos
Ecossistema , Modelos Biológicos , Animais , Comportamento Predatório , Dinâmica Populacional
19.
Biodivers Data J ; 12: e113125, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38505125

RESUMO

There is no information on the species associated with the mesophotic reefs of Banderas Bay, located in the central Mexican Pacific. This study analysed the reef fish assemblage from three depths (50, 60 and 70 m) in three sampling sites of the southern submarine canyon of the Bay: Los Arcos, Bajo de Emirio and Majahuitas. Several analyses were performed to test the hypothesis that there are important differences in fish abundance and species composition between sites and depths. Twenty-two species of bony fishes grouped in 14 families were recorded. PERMANOVA results showed that there were no significant differences in fish diversity parameters between sites, indicating a certain uniformity in their distribution. However, nine species were exclusive to one site and depth (five singleton species with only one individual recorded and four unique species recorded only once). On the other hand, there were significant differences between depths, mainly between 50 and 70 m. Diversity decreases with depth and species composition changes. SIMPER, Shade Plot and NMDS analysis show the most representative species at each depth, with at least half of the species (11) recorded only at 50 m and four species at the deeper levels (60 - 70 m). The observed assemblage includes several of the most caught species in the shallow water artisanal fishery, which is the most traditional and common type of fishery in the Bay. In addition, the Pomacanthuszonipectus (Cortés angelfish) is of particular interest, as it has a special protection status in the official Mexican standard (NOM-059-SEMARNAT, 2010) due to its use as an ornamental species in aquaria. We hypothesised that the mesophotic zone may serve as a refuge for these fishes, so we propose that the information obtained is an important basis for new research aimed at the sustainable management of fisheries in the area.

20.
Entropy (Basel) ; 26(3)2024 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-38539708

RESUMO

The insect predator-prey system mediates several feedback mechanisms which regulate species abundance and spatial distribution. However, the spatiotemporal dynamics of such discrete systems with the refuge effect remain elusive. In this study, we analyzed a discrete Holling type II model incorporating the refuge effect using theoretical calculations and numerical simulations, and selected moths with high and low growth rates as two exemplifications. The result indicates that only the flip bifurcation opens the routes to chaos, and the system undergoes four spatiotemporally behavioral patterns (from the frozen random pattern to the defect chaotic diffusion pattern, then the competition intermittency pattern, and finally to the fully developed turbulence pattern). Furthermore, as the refuge effect increases, moths with relatively slower growth rates tend to maintain stability at relatively low densities, whereas moths with relatively faster growth rates can induce chaos and unpredictability on the population. According to the theoretical guidance of this study, the refuge effect can be adjusted to control pest populations effectively, which provides a new theoretical perspective and is a feasible tool for protecting crops.

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