Journal articles on the topic 'Insect populations'
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1
Pimentel, David. "Insect population responses to environmental stress and pollutants." Environmental Reviews 2, no. 1 (January 1, 1994): 1–15. http://dx.doi.org/10.1139/a94-001.
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Insects and other related arthropods make up about 90% of all plant and animal species in the world. They are vital to the functioning of the ecosystem and biosphere, and neither of these systems can operate effectively without insect interactions. Because of their major ecological and economic roles in nature and society, the beneficial and pest activities of insects need to be clearly understood. Insect populations are being stressed directly by the action of temperature, moisture, and a wide array of chemical Ö öpollutants (pesticides, fertilizers, air pollutants, and numerous other chemicals) that are dispersed through air, water, and soil. Insects are affected by this same group of stresses indirectly, through their food plants, parasites, and predators. Depending on the species and the particular stress affecting it, insect populations respond by increasing or decreasing in numbers. The responses of insect populations to various direct and indirect environmental stresses and chemical pollutants are assessed. Some insect populations increase, while others decline. The responses were determined by the particular environmental stress, the insect species, and the stage at which they were exposed to the stress.Key words: insects, environment, pollutants, stress, water, herbicides.
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Lancaster, Jill, and Barbara Downes. "Aquatic versus Terrestrial Insects: Real or Presumed Differences in Population Dynamics?" Insects 9, no. 4 (November 1, 2018): 157. http://dx.doi.org/10.3390/insects9040157.
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The study of insect populations is dominated by research on terrestrial insects. Are aquatic insect populations different or are they just presumed to be different? We explore the evidence across several topics. (1) Populations of terrestrial herbivorous insects are constrained most often by enemies, whereas aquatic herbivorous insects are constrained more by food supplies, a real difference related to the different plants that dominate in each ecosystem. (2) Population outbreaks are presumed not to occur in aquatic insects. We report three examples of cyclical patterns; there may be more. (3) Aquatic insects, like terrestrial insects, show strong oviposition site selection even though they oviposit on surfaces that are not necessarily food for their larvae. A novel outcome is that density of oviposition habitat can determine larval densities. (4) Aquatic habitats are often largely 1-dimensional shapes and this is presumed to influence dispersal. In rivers, drift by insects is presumed to create downstream dispersal that has to be countered by upstream flight by adults. This idea has persisted for decades but supporting evidence is scarce. Few researchers are currently working on the dynamics of aquatic insect populations; there is scope for many more studies and potentially enlightening contrasts with terrestrial insects.
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Choo, Juanita. "Potential ecological implications of human entomophagy by subsistence groups of the Neotropics." Terrestrial Arthropod Reviews 1, no. 1 (2008): 81–93. http://dx.doi.org/10.1163/187498308x345442.
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AbstractThe practice of human entomophagy is important to the livelihood of many subsistence cultures. Insect foods are a source of protein in traditional diets and are often considered delicacies. While considerable research has been conducted on the nutritional benefits of insects to human welfare, there has been little focus on understanding how harvests of insect foods can potentially impact local ecology. In this paper, I address the potential ecological consequences of insect harvesting activities with a focus on Neotropical subsistence communities. I confine my discussion to four insect foods - palm weevils, bruchid beetles, ants, and termites. Insect harvesting has the potential to not only influence insect populations but also to alter ecological interactions between plant and insects. I propose that rigorous studies on insect harvest intensity, in space and time, are necessary steps in understanding the full effects of harvesting activities on insect populations and broader forest communities. Research on the ecological implications of insect harvests are important in the face of potential increases in the demand for insect food as a result of rapid population growth within indigenous communities and increased hunting pressures on wild game.
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Okeke, T.E., Ewuim, S.C., Ononye, B.U., Chukwudebelu, A.E., and Mbelede, K.C. "Efficiency of Different Techniques in Collecting Insects in Environments Exposed to Palm Oil and Spent Engine Oil Effluents in Abakiliki, Ebonyi State." Asian Journal of Research in Zoology 7, no. 1 (February 5, 2024): 47–57. http://dx.doi.org/10.9734/ajriz/2024/v7i1139.
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This study investigates the ecological consequences of palm oil and spent engine oil effluents on insect populations, employing a comparative analysis of two widely used collection techniques: pitfall traps and sweep netting. The aim was to assess the effectiveness of these methods in capturing and quantifying insect diversity and abundance in polluted environments. The research was conducted in selected sites exposed to palm oil and spent engine oil effluents, with corresponding control sites for comparison. Pitfall traps and sweep netting were deployed simultaneously to collect insects across various habitats impacted by the aforementioned effluents. The collected specimens were then identified to the lowest taxonomic level possible, and population data were analyzed to evaluate the relative impact of each effluent type on insect communities. Furthermore, statistical analyses were employed to compare the efficiency of pitfall traps and sweep netting in detecting changes in insect populations. The study revealed that pitfall traps recorded significantly higher number of insects (72.93%) than sweep nets (27.07%) in sites exposed to palm oil effluent (P<0.05). The result obtained in the site exposed to spent engine oil effluent showed that pitfall traps recorded significantly higher number of insects (80.61%) than sweep nets (19.39%) (P<0.05). This study contributes to the ecological repercussions of industrial effluents on insect populations, offering a methodological comparison that can enhance the precision of future insect-related environmental assessments.
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Quan, Yudong, Jing Yang, Yueqin Wang, Patricia Hernández-Martínez, Juan Ferré, and Kanglai He. "The Rapid Evolution of Resistance to Vip3Aa Insecticidal Protein in Mythimna separata (Walker) Is Not Related to Altered Binding to Midgut Receptors." Toxins 13, no. 5 (May 20, 2021): 364. http://dx.doi.org/10.3390/toxins13050364.
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Laboratory selection for resistance of field populations is a well-known and useful tool to understand the potential of insect populations to evolve resistance to insecticides. It provides us with estimates of the frequency of resistance alleles and allows us to study the mechanisms by which insects developed resistance to shed light on the mode of action and optimize resistance management strategies. Here, a field population of Mythimna separata was subjected to laboratory selection with either Vip3Aa, Cry1Ab, or Cry1F insecticidal proteins from Bacillus thuringiensis. The population rapidly evolved resistance to Vip3Aa reaching, after eight generations, a level of >3061-fold resistance, compared with the unselected insects. In contrast, the same population did not respond to selection with Cry1Ab or Cry1F. The Vip3Aa resistant population did not show cross resistance to either Cry1Ab or Cry1F. Radiolabeled Vip3Aa was tested for binding to brush border membrane vesicles from larvae from the susceptible and resistant insects. The results did not show any qualitative or quantitative difference between both insect samples. Our data, along with previous results obtained with other Vip3Aa-resistant populations from other insect species, suggest that altered binding to midgut membrane receptors is not the main mechanism of resistance to Vip3Aa.
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Singh, Sujata, Archana Singh, Varsha Baweja, Amit Roy, Amrita Chakraborty, and Indrakant Kumar Singh. "Molecular Rationale of Insect-Microbes Symbiosis—From Insect Behaviour to Mechanism." Microorganisms 9, no. 12 (November 24, 2021): 2422. http://dx.doi.org/10.3390/microorganisms9122422.
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Insects nurture a panoply of microbial populations that are often obligatory and exist mutually with their hosts. Symbionts not only impact their host fitness but also shape the trajectory of their phenotype. This co-constructed niche successfully evolved long in the past to mark advanced ecological specialization. The resident microbes regulate insect nutrition by controlling their host plant specialization and immunity. It enhances the host fitness and performance by detoxifying toxins secreted by the predators and abstains them. The profound effect of a microbial population on insect physiology and behaviour is exploited to understand the host–microbial system in diverse taxa. Emergent research of insect-associated microbes has revealed their potential to modulate insect brain functions and, ultimately, control their behaviours, including social interactions. The revelation of the gut microbiota–brain axis has now unravelled insects as a cost-effective potential model to study neurodegenerative disorders and behavioural dysfunctions in humans. This article reviewed our knowledge about the insect–microbial system, an exquisite network of interactions operating between insects and microbes, its mechanistic insight that holds intricate multi-organismal systems in harmony, and its future perspectives. The demystification of molecular networks governing insect–microbial symbiosis will reveal the perplexing behaviours of insects that could be utilized in managing insect pests.
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Styer, E. L., and J. J. Hamm. "Detection and Identification of Viruses in Economically Important Insects." Microscopy and Microanalysis 6, S2 (August 2000): 666–67. http://dx.doi.org/10.1017/s1431927600035820.
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Economically important insects include pests of plants, animals and stored products as well as insects produced commercially (honey bees, silkworms, insects for fish bait and food for birds and zoo animals). Other insects are produced in large numbers for experimental purposes, biological control of insect pests and weeds and the production of sterile insects for population suppression. Insect viruses may affect morphology, physiology and behavior, often reducing longevity and reproductive potential. Thus insect viruses can be used as biological control agents of pest insects. Insect viruses may also interfere with the production or function of biological control agents (e.g., parasitoids and predators) and insects used for research purposes. Therefore, it is advantageous to screen commercial and research colonies and imported insects for viruses.Electron microscopy of negatively stained specimens (NS EM) offers a relatively rapid and inexpensive means of screening populations of insects for the presence of viruses or viruslike particles and to monitor the progress of virus control programs.
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Wang, Zhengyan, Zhenzhen Chang, Zhiyuan Liu, and Shan Zhang. "Influences of Microbial Symbionts on Chemoreception of Their Insect Hosts." Insects 14, no. 7 (July 14, 2023): 638. http://dx.doi.org/10.3390/insects14070638.
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Chemical communication is widespread among insects and exploited to adjust their behavior, such as food and habitat seeking and preferences, recruitment, defense, and mate attraction. Recently, many studies have revealed that microbial symbionts could regulate host chemical communication by affecting the synthesis and perception of insect semiochemicals. In this paper, we review recent studies of the influence of microbial symbionts on insect chemoreception. Microbial symbionts may influence insect sensitivity to semiochemicals by regulating the synthesis of odorant-binding proteins or chemosensory proteins and olfactory or gustatory receptors and regulating host neurotransmission, thereby adjusting insect behavior. The manipulation of insect chemosensory behavior by microbial symbionts is conducive to their proliferation and dispersal and provides the impetus for insects to change their feeding habits and aggregation and dispersal behavior, which contributes to population differentiation in insects. Future research is necessary to reveal the material and information exchange between both partners to improve our comprehension of the evolution of chemoreception in insects. Manipulating insect chemoreception physiology by inoculating them with microbes could be utilized as a potential approach to managing insect populations.
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Drake, VA. "The influence of weather and climate on agriculturally important insects: an Australian perspective." Australian Journal of Agricultural Research 45, no. 3 (1994): 487. http://dx.doi.org/10.1071/ar9940487.
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Weather and climate affect insects and other arthropods of importance to agriculture in a wide variety of ways. Pest and beneficial insects, and insect vectors of plant and animal diseases, are all influenced both directly and indirectly by temperature, rainfall, wind, etc. These influences can be immediate or cumulative, and they can act either at the production site or, in the case of migrant species, at locations distant from it. Weather and climate influence, often very significantly, the development rate, survival, fitness, and level of activity of individual insects; the phenology, distribution, size, and continuity of insect populations; migration and the re-establishment of populations following local extinction; the initiation of outbreaks; the susceptibility of crops and stock to insect attack; and the capacity of producers to manage insect populations. In Australia, the high variability of rainfall is of particular significance in determining the size and quality of insect populations. Windborne migration can be important for transporting these populations into agricultural regions, and low winter temperatures in the south of the continent limit the distribution of tropical species. Current Australian research on these topics is directed mainly at the development of pest-forecasting systems, and at estimating the impact of global greenhouse warming.
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Doberski, Julian. "Analysing insect populations: what limits insect abundance?" Journal of Biological Education 26, no. 4 (December 1992): 279–86. http://dx.doi.org/10.1080/00219266.1992.9655286.
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Quisenberry, S. S., D. J. Schotzko, P. F. Lamb, and F. L. Young. "Insect Distribution in a Spring Pea-Winter Wheat-Spring Barley Crop Rotation System." Journal of Entomological Science 35, no. 3 (July 1, 2000): 327–33. http://dx.doi.org/10.18474/0749-8004-35.3.327.
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The effects of tillage method (conventional or conservative) and weed management level (recommended or minimum) on insect distribution in a wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and pea (Pisum sativum L.) rotation were studied. Aphids were the major insect species on winter wheat and spring barley, but were not of economic importance. Beneficial species impacted aphid population levels by maintaining their numbers below economic thresholds. Tillage method and weed management level had limited impact on aphid and beneficial insect populations. Pea leaf weevil (Sitonia lineatus [L.]) and pea weevil (Bruchus pisorum [L.]) populations reached economic injury levels in 1992; two insecticide applications were needed. Pea leaf weevil populations did not reach economic levels in 1993; however, pea weevil populations reached an economic level at flowering stage and an insecticide was applied. Pea leaf weevil populations were higher in conventional tillage plots compared with conservation tillage plots. Early-season insecticide applications suppressed beneficial insects in the pea plots.
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Mawan, Amanda, Rizky Nazarreta, Kasmiatun Kasmiatun, Bonjok Istiaji, Purnama Hidayat, and Damayanti Buchori. "Pengaruh cahaya artifisial di malam hari (artificial light at night-ALAN) terhadap serangga." Jurnal Entomologi Indonesia 19, no. 3 (February 3, 2023): 255–60. http://dx.doi.org/10.5994/jei.19.3.255.
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Insect populations have declined significantly over the last few decades. Anthropogenic factors such as deforestation, land-use change, climate change, and pesticides play a major role in insect population decline. In addition to those factors, insects also face challenges from air, noise, and light pollution derived from human activities. Light pollution in the form of artificial light at night (ALAN) is generally known to be one of the factors driving insect declines but it has rarely been studied in Indonesia. In this literature review, we collected empirical evidence from previous studies to provide a comprehensive report on the impact of ALAN on insects. Most studies demonstrate a decline in insect populations in areas with high ALAN intensity, such as urban areas. Furthermore, ALAN was reported to disrupt insect visual systems, which results in disturbances to predator avoidance and foraging movements. Until now, most work related to artificial light in Indonesia have focused on light as a method of controlling pests. Hence, studies related to artificial light as a pollutant are urgently needed to increase our understanding of the effects of ALAN on the survival of organisms, especially insects. Future research must seek suitable solutions to create environmentally and ecologically friendly conditions for various organisms, especially those susceptible to the negative effects of light, such as insects.
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Sandra, Santi, Lizawati Lizawati, and Wilyus Wilyus. "DETEKSI SERANGGA HAMA PADA GUDANG PENYIMPANAN BIJI PINANG (Areca catechu) MENGGUNAKAN BEBERAPA METODEPENGAMBILAN SAMPEL." Jurnal Media Pertanian 6, no. 1 (April 6, 2021): 29. http://dx.doi.org/10.33087/jagro.v6i1.113.
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The research aims to detect insect in betel nut storage (Areca catechu) using some sampling methods. The research was conducted by survey method using three sampling methods, namely hand sampling method, yellow sticky trap method, and dome trap method. The parameters observed were types of insect pests found, insect populations obtained, and abundance of pest insect populations. The research was conducted from July to October 2018 in four betel nut storagesin Jambi City and Muaro Jambi District. Insects found in the betel nut storages with three sampling methods were 28 pest species. In the hand sampling method found 16 types of pest insects, in the yellow sticky trap trap method found 21 types of insect pests, and in the dome trap method found 21 types of insect pests. The dominant insects found in the three sampling methods were Ahasverus advena, Araecerus fasciculatus, Callosobruchus spp., Carpophilus dimidiatus, Cryptolestes ferrugineus, Cryptolestes pusillus, Hypothenemus hampei, Lasioderma serricorne, Lophocateres pusillus, Oryzaephilus mercator, Typhaea stercorea, and Tribolium castaneum.
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Verma, Sweta, Doddachowdappa Sagar, Hemant Kumar, and Sujatha G S. "Abiotic Factors as Game Changer in Sex Ratio Distortion of Insects." International Journal of Environment and Climate Change 14, no. 7 (July 6, 2024): 332–42. http://dx.doi.org/10.9734/ijecc/2024/v14i74274.
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Sex ratios in insect populations are critical in shaping their reproductive dynamics, genetic diversity, and ecological interactions. While genetic factors often determine sex, abiotic factors have emerged as important influencers of sex ratios in insects. The influence of abiotic factors on sex ratios in insects is of scientific interest and holds practical implications for insect conservation and management. As environmental conditions change due to global warming, understanding how sex ratios respond to these changes can aid in predicting population dynamics and designing effective conservation strategies for biocontrol agents as well as the management of insect pests. Abiotic stressors, including fluctuations in temperature, humidity variations, altitude & latitude, nutrition and chemical exposure have been shown to disrupt the precise balance of hormonal and genetic cues governing sex determination in insects. Insects being ectothermic, body temperature depends on the surrounding environmental conditions and are highly vulnerable to the change in climate. This review explores the intricate relationship between abiotic stress and sex determination mechanisms in insects, highlighting recent advances in our understanding of how stress-induced alterations especially environment in hormone signaling, gene expression, and epigenetic modifications can lead to skewed sex ratios and developmental anomalies. Regardless of the advances in this area, notable research gaps are still present. Future studies on the multiple abiotic factors and their synergistic effects will give a more detailed study of insect populations, and their ecosystems. This comprehensive review delves into the multifaceted interactions between abiotic factors and sex differentiation in insects. In conclusion, the abiotic factors especially temperature are indeed game changers in the insect sex ratio dynamics.
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Acharya, Tej P., Gregory E. Welbaum, and Ramón A. Arancibia. "Low Tunnels Reduce Insect Populations, Insecticide Application, and Chewing Insect Damage on Brussels Sprouts." Journal of Economic Entomology 113, no. 5 (July 22, 2020): 2553–57. http://dx.doi.org/10.1093/jee/toaa154.
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Abstract Low tunnels covered with spun-bonded fabric (row covers) provide season extension for vegetable production and also afford a physical barrier against airborne insects and other non-soil pests. Brussels sprouts, Brassica oleracea L. group Gemmifera (Brassicaceae), is a popular vegetable in local markets in Virginia; however, unprotected field production is severely affected by insect pest infestation. This study’s objective was to determine the level of protection low tunnels provide against insect infestation and leaf herbivory injury. The experiment was conducted at the Virginia Tech Eastern Shore Agricultural Research and Extension Center in Painter, Virginia. The experimental design was split-plot with polyethylene soil mulches (white or black) as whole plot factors and production systems (low tunnel or open field) as subplot factors. In this study, low tunnels reduced insect infestation and chewing herbivory leaf injury to Brussels sprouts. Compared to an unprotected open field, infestations of lepidopteran insects and harlequin bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae) were reduced on plants under low tunnels. However, aphids (Hemiptera: Aphidae) infestation occurred under low tunnels in fall. There was no effect of color mulches (white or black) and no interaction between tunnel and mulch color on insect infestation and chewing injury. Fewer insect infestations and feeding injury indicate that low tunnels can be an effective management tool for sustainable vegetable production.
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Ben Dhahbi, Anis, Yassine Chargui, Salah Mahmoud Boulaaras, and Sana Ben Khalifa. "A One-Sided Competition Mathematical Model for the Sterile Insect Technique." Complexity 2020 (July 30, 2020): 1–12. http://dx.doi.org/10.1155/2020/6246808.
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We study a simple mathematical model describing the dynamics of a wild-type pest insects population experiencing competition from sterile insects (one-sided competition). This model can be used for conceiving control strategies based on the Sterile Insect Technique (SIT) or the Incompatible Insect Technique (IIT), aiming to reduce or eradicate Red Palm Weevil (RPW) populations in some target regions. We show that suppression may occur for continuous and periodic release strategies for various intraspecific and interspecific submodels except in the case of a single release strategy where a strong Allee effect is required.
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Hagstrum, David William, and Paul Whitney Flinn. "Modern Stored-Product Insect Pest Management." Journal of Plant Protection Research 54, no. 3 (July 1, 2014): 205–10. http://dx.doi.org/10.2478/jppr-2014-0031.
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Abstract Stored-product entomologists have a variety of new monitoring, decision-making, biological, chemical, and physical pest management tools available to them. Two types of stored-product insect populations are of interest: insects of immediate economic importance infesting commodities, and insects that live in food residues in equipment and facilities. The sampling and control methods change as grain and grain products move from field to consumer. There are also some changes in the major insect pest species to take into consideration. In this review, we list the primary insect pests at each point of the marketing system, and indicate which sampling methods and control strategies are most appropriate. Economic thresholds for insect infestation levels developed for raw commodity storage, processing plants, and retail business allow sampling-based pest management to be done before insect infestations cause economic injury. Taking enough samples to have a representative sample (20-30 samples) will generally provide enough information to classify a population as above or below an economic threshold.
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Schrader, Wayne L., Karen L. Robb, and Valerie J. Mellano. "Protective Border Plantings for Ag/Urban Interfaces." HortScience 33, no. 3 (June 1998): 491d—491. http://dx.doi.org/10.21273/hortsci.33.3.491d.
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Protective border barriers were established at three sites in commercial floriculture, and strawberry fields in San Diego County, Calif. These border plantings were used to provide a physical barrier between agricultural fields and adjacent urban development, and to evaluate the effects of border plantings on insect populations, spray drift, and crop/barrier interactions. Border plantings consisted of native plants with overlapping flowering periods to provide nectar and pollen to beneficial insects throughout the year. Yellow sticky traps were used to monitor insect populations, and water sensitive paper was used to evaluate the reduction of spray drift by the border plantings. Results indicate that protective border plantings: 1) can be used to form attractive physical barriers that reduce visual pollution and spray drift; 2) provide habitat for pests as well as beneficial insects; 3) support beneficial insects that may help reduce the population peaks of pest insects during spring and summer months; and 4) have little effect on adjacent crop fields.
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Hill, M. G., S. J. Dobson, C. M. Mckenna, B. J. Maher, and N. A. Mauchline. "Comparing armoured scale insect (Hemiberlesia spp) populations on male and female Actinidia chinensis vines." New Zealand Plant Protection 62 (August 1, 2009): 274–78. http://dx.doi.org/10.30843/nzpp.2009.62.4795.
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The wood and leaves of Actinidia chinensis Hort16A and two male pollinisers A chinensis Meteor and A chinensis Sparkler from commercial kiwifruit orchards were sampled for the presence of armoured scale insects during winter 2007 and summer 2008/09 The numbers and species of scale insect were recorded Meteor had high armoured scale insect populations on its wood with approximately 10 times more armoured scale insects than Sparkler or Hort16A The leaves of Hort16A vines adjacent to Meteor vines had 44 more armoured scale insects and were 30 more likely to be infested by scale insects than the leaves of Hort16A vines adjacent to Sparkler vines The implications of these findings for armoured scale insect control on Hort16A fruit are discussed
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Campos-Herrera, Raquel, Ignacio Vicente-Díez, Magda Galeano, Maryam Chelkha, María del Mar González-Trujillo, Miguel Puelles, David Labarga, Alicia Pou, Javier Calvo, and José Eduardo Belda. "Intraspecific virulence of entomopathogenic nematodes against the pests Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae)." Journal of Nematology 53, no. 1 (January 1, 2021): 1–14. http://dx.doi.org/10.21307/jofnem-2021-102.
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Abstract Entomopathogenic nematodes (EPN) are excellent biocontrol agents against various insect pests. Novel biotechnological approaches can enhance their utility against insects above-ground, opening a new venue for selecting superior EPN against certain insects. We hypothesize that different populations of the same species but from different origins (habitat, ecoregion) will differ in their virulence. This study aimed to evaluate the virulence of various EPN populations against two pests of worldwide incidence and damage to high value crops: Frankliniella occidentalis (Thysanoptera: Thripidae) and Tuta absoluta (Lepidoptera: Gelechiidae). We tested 10 EPN populations belonging to three EPN species: Heterorhabditis bacteriophora (Koppert, MG-618b, AM-203, RM-102), Steinernema feltiae (Koppert, RS-5, AM-25, RM-107), and Steinernema carpocapsae (Koppert, MG-596a). Each EPN population was tested at two concentrations. Frankliniella occidentalis was tested at 160 and 80 IJs/cm2 and T. absoluta at 21 and 4 IJs/cm2. Control treatments followed the same experimental procedure but only adding distilled water. Overall, whenever different, higher IJs concentration resulted in lower adult emergence, higher larval mortality, and shorter time to kill the insects. Considering the low concentration, S. feltiae provided the best results for both insects and instars investigated, while H. bacteriophora and S. carpocapsae required a high concentration to reach similar or slightly better results. Differences among populations of each of the species were detected, but only the native populations of H. bacteriophora populations showed consistently higher control values against both insects/instar compared with the commercial one. Differences among S. feltiae and S. carpocapsae populations depended on the IJs concentration, insect, and instar. We consider S. feltiae a very promising species for their application against F. occidentalis and T. absoluta, with the Koppert population as the most consistent among the populations tested. Specific EPN-populations of S. carpocapsae and H. bacteriophora were good candidates against certain instar/insects at high concentrations. This study emphasized the importance of intraspecific variability for EPN virulence.
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Páez, David J., and Arietta E. Fleming-Davies. "Understanding the Evolutionary Ecology of host–pathogen Interactions Provides Insights into the Outcomes of Insect Pest Biocontrol." Viruses 12, no. 2 (January 25, 2020): 141. http://dx.doi.org/10.3390/v12020141.
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The use of viral pathogens to control the population size of pest insects has produced both successful and unsuccessful outcomes. Here, we investigate whether those biocontrol successes and failures can be explained by key ecological and evolutionary processes between hosts and pathogens. Specifically, we examine how heterogeneity in pathogen transmission, ecological and evolutionary tradeoffs, and pathogen diversity affect insect population density and thus successful control. We first review the existing literature and then use numerical simulations of mathematical models to further explore these processes. Our results show that the control of insect densities using viruses depends strongly on the heterogeneity of virus transmission among insects. Overall, increased heterogeneity of transmission reduces the effect of viruses on insect densities and increases the long-term stability of insect populations. Lower equilibrium insect densities occur when transmission is heritable and when there is a tradeoff between mean transmission and insect fecundity compared to when the heterogeneity of transmission arises from non-genetic sources. Thus, the heterogeneity of transmission is a key parameter that regulates the long-term population dynamics of insects and their pathogens. We also show that both heterogeneity of transmission and life-history tradeoffs modulate characteristics of population dynamics such as the frequency and intensity of “boom–bust" population cycles. Furthermore, we show that because of life-history tradeoffs affecting the transmission rate, the use of multiple pathogen strains is more effective than the use of a single strain to control insect densities only when the pathogen strains differ considerably in their transmission characteristics. By quantifying the effects of ecology and evolution on population densities, we are able to offer recommendations to assess the long-term effects of classical biocontrol.
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Suinyuy, Terence N., John S. Donaldson, and Steven D. Johnson. "Geographical matching of volatile signals and pollinator olfactory responses in a cycad brood-site mutualism." Proceedings of the Royal Society B: Biological Sciences 282, no. 1816 (October 7, 2015): 20152053. http://dx.doi.org/10.1098/rspb.2015.2053.
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Brood-site mutualisms represent extreme levels of reciprocal specialization between plants and insect pollinators, raising questions about whether these mutualisms are mediated by volatile signals and whether these signals and insect responses to them covary geographically in a manner expected from coevolution. Cycads are an ancient plant lineage in which almost all extant species are pollinated through brood-site mutualisms with insects. We investigated whether volatile emissions and insect olfactory responses are matched across the distribution range of the African cycad Encephalartos villosus . This cycad species is pollinated by the same beetle species across its distribution, but cone volatile emissions are dominated by alkenes in northern populations, and by monoterpenes and a pyrazine compound in southern populations. In reciprocal choice experiments, insects chose the scent of cones from the local region over that of cones from the other region. Antennae of beetles from northern populations responded mainly to alkenes, while those of beetles from southern populations responded mainly to pyrazine. In bioassay experiments, beetles were most strongly attracted to alkenes in northern populations and to the pyrazine compound in southern populations. Geographical matching of cone volatiles and pollinator olfactory preference is consistent with coevolution in this specialized mutualism.
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Tarasova, O. V., and P. A. Krasnoperova. "Spatio-Temporal Connectivity of the Long-Term Dynamics of the Forest Phyllophagus Insects’ Abundance." Лесоведение, no. 2 (March 1, 2023): 161–73. http://dx.doi.org/10.31857/s0024114823020109.
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The study was conducted regarding the conjugation of the population dynamics of different forest insects species under different landscape conditions on the territory of the Krasnoturansky pine forest (South of the Krasnoyarsk Territory). The population dynamics conjugation indicates the presence of an ecological mechanism that leads to the coordination of the temporal series of different species’ population dynamics in one habitat or one species in different habitats. This means that using the conjugation indicators of insect dynamics one can indirectly assess the influence of various factors affecting these populations. To assess the spatio-temporal synchronization of the population dynamics of insects in different landscape conditions, the data of the phyllophagous insects counts for the period from 1979 to 2016 were used. According to the phases of dynamics, although the periods of cyclic fluctuations of phyllophages’ populations in different stows are close, the characteristics of the phyllophagous insects number dynamics still differ in both the absolute values and the phases of dynamics, even when the distance between the test sites is relatively small. The “memory” of the system, expressed in the order of the autoregressive model of the population dynamics, is fairly large for the studied complexes of phyllophagous species: the current value of the phyllophagous populations density can be influenced by the population density values from as far as four years before the counts. Such values of “memory” lead to an increase in the populations’ stability margin, and a decrease in the risks of developing insect outbreaks. The determination coefficients close to 1 for the phyllophages dynamics models in the stows of the Krasnoturansky pine forest indicate a weak influence of modifying factors (such as weather) on the population dynamics.
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Purnomo, Hari, and Moh Dana Parawangsa. "Keragaman Serangga Hama dan Musuh Alami Lahan Pertanian Padi Organik (Oryza Sativa L) Desa Rowosari Kecamatan Sumberjambe Kabupaten Jember." Berkala Ilmiah Pertanian 6, no. 4 (November 1, 2023): 170. http://dx.doi.org/10.19184/bip.v6i4.39180.
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The application of organic rice farming systems is a solution to the negative impacts of using chemicals in the application of conventional farming systems. Organic rice cultivation cannot be separated from the presence of insect pests that attack cultivated plants. Naturally, in an ecosystem that is still good, natural enemies are already present in nature without human intervention. The existence of natural enemies in a field can suppress the existing population of insect pests, so that their presence is very helpful in maintaining the balance of the existing insect pest populations. The stability of insect populations in an agricultural ecosystem is largely determined by the high diversity of insect pests and natural enemies found in a field. Thus there is a need for research on the diversity of insect pests and natural enemies as information about which insect families are found on organic rice farming land in Rowosari Village, as well as a consideration for farmers in applying appropriate control methods. This study used yellow pan trap, sweep net and vacuum cleaner insect monitoring tools. The research was conducted on 3 observation plots in the organic rice fields of Tani Jaya II Group, Rowosari Village, Sumberjambe District, Jember Regency. Observations were made 10 times from the vegetative phase to the generative phase of rice aged 7 to 77 days after planting. Observational data were then identified and then analyzed using the Shanon-Wiener Diversity Index (H), Evenness Evenness Index (E), Simpson Dominance Index (D), and Margalef Species Richness Index (R). The results showed that there were 7 families of Pest Insects found on organic rice farming in Rowosari Village, including Pyralidae, Alydidae, Grylidae, Cicadellidae, Chrysomelidae, Acrididae, and Nymphalidae. Natural Enemy Insects found were 9 families including Coccinellidea, Coenagrionidae, Gomphidae, Penttomidae, Meoidae, Miridae, Ichneumonidae, Staphylinidae, and Sciomyzidae. Neutral insects found were as many as 4 families, including Muscidae, Vespidae, Tephritidae, and Drosophilidae. The population of insect pests and natural enemies of organic rice farming land in Rowosari Village is quite balanced with a Diversity Index (H') of 2.32 and Species Richness Index (R) of 2.98, Evenness index (E') of 0.77 which is in the almost even and Dominance (D) 0.13 which means not dominating.
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Hawkins and Holyoak. "Transcontinental Crashes of Insect Populations?" American Naturalist 152, no. 3 (1998): 480. http://dx.doi.org/10.2307/2463478.
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Albuquerque de Araujo, Anderson L., José L. Boldrini, Roberto C. Cabrales, Enrique Fernández-Cara, and Milton L. Oliveira. "Optimal Control of Insect Populations." Mathematics 9, no. 15 (July 26, 2021): 1762. http://dx.doi.org/10.3390/math9151762.
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We consider some optimal control problems for systems governed by linear parabolic PDEs with local controls that can move along the domain region Ω of the plane. We prove the existence of optimal paths and also deduce the first order necessary optimality conditions, using the Dubovitskii–Milyutin’s formalism, which leads to an iterative algorithm of the fixed-point kind. This problem may be considered as a model for the control of a mosquito population existing in a given region by using moving insecticide spreading devices. In this situation, an optimal control is any trajectory or path that must follow such spreading device in order to reduce the population as much as possible with a reasonable not too expensive strategy. We illustrate our results by presenting some numerical experiments.
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ZENG, BaoSheng, YongPing HUANG, AnJiang TAN, ShuQing CHEN, and Jun XU. "Genetic Regulation of Insect Populations." SCIENTIA SINICA Vitae 43, no. 12 (December 1, 2013): 1098–104. http://dx.doi.org/10.1360/052013-315.
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Hawkins, Bradford A., and Marcel Holyoak. "Transcontinental Crashes of Insect Populations?" American Naturalist 152, no. 3 (September 1998): 480–84. http://dx.doi.org/10.1086/286184.
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BENDELL, BARRY E., and DONALD K. McNICOL. "Estimation of nektonic insect populations." Freshwater Biology 18, no. 1 (August 1987): 105–8. http://dx.doi.org/10.1111/j.1365-2427.1987.tb01298.x.
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Olson, D., and D. Andow. "Patch edges and insect populations." Oecologia 155, no. 3 (December 21, 2007): 549–58. http://dx.doi.org/10.1007/s00442-007-0933-6.
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Pimentel, Marco Aurélio Guerra, Lêda Rita D'Antonino Faroni, Maurílio Duarte Batista, and Felipe Humberto da Silva. "Resistance of stored-product insects to phosphine." Pesquisa Agropecuária Brasileira 43, no. 12 (December 2008): 1671–76. http://dx.doi.org/10.1590/s0100-204x2008001200005.
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The objectives of this work were to assess phosphine resistance in insect populations (Tribolium castaneum, Rhyzopertha dominica, Sitophilus zeamais and Oryzaephilus surinamensis) from different regions of Brazil and to verify if the prevailing mechanism of phosphine resistance in these populations involves reduced respiration rates. Sixteen populations of T. castaneum, 15 of R. dominica, 27 of S. zeamais and eight of O. surinamensis were collected from 36 locations over seven Brazilian states. Each population was tested for resistance to phosphine, based on the response of adults to discriminating concentrations, according to FAO standard method. For each insect species, the production of carbon dioxide of the most resistant and of the most susceptible populations was inversely related to their phosphine resistance. The screening tests identified possible phosphine resistant populations. R. dominica and O. surinamensis were less susceptible to phosphine than the other two species. The populations with lower respiration rate showed a lower mortality at discriminating concentration, possibly related to a phosphine resistance mechanism. Phosphine resistance occurs in stored-product insects, in different regions of Brazil, and the resistance mechanism involves reduced respiration rate.
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Montong, Vivi, and Christina Salaki. "Insects as Carriers of Ralstonia solanacearum Phylotype IV on Kepok Banana Flowers in South Minahasa and Minahasa Districts." International Journal of ChemTech Research 13, no. 1 (2020): 199–205. http://dx.doi.org/10.20902/ijctr.2019.130124.
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The scope of this study is the management of insects that carry the cause of banana blood disease (BBD), Ralstonia solanacearum Phylotype IV. The objectives of this study are: (1) to study the diversity and density of visitor insect populations to the Kepok banana flower, and (2) to identify insects in the Kepok banana flower that act as carriers of R. solanacearum Phylotype IV, and the population density of these bacteria was carried by each insect. Sampling of banana plantations is done based on pusposive sampling method. Insect collection uses a modified insect net, and insect collection uses modified insect nets, and insects were morphologically identified. This bacterial isolation was carried out based on the spread method on NA + TZC media. Inoculation of bacterial isolates was carried out by injection method on the tip of an mature Kepok banana. Density of insects visitors banana flower per tree in South Minahasa and Minahasa regencies are as follows: Oscinella sp. (15.50 and 18.08 individuals), Aphis mellifera (0.50 and 1.58), Chelisoches morio (0.28 and 0.20 individuals, and Dolichoderus sp. (1.44 and 6.21 individuals). All insects on the Kepok banana flower in South Minahasa and Minahasa carry Ralstonia solanacearum Phylotype IV. Oscinella sp., Aphis mellifera, Chelisoches morio, and Dolichoderus sp. in both districts it brought 17,636.39 and 75,533.33 CFU / ml, 15,666.67 and 17,400.00 CFU / ml, 113.33 and 2,667.67 CFU / ml, and 2,400.00 CFU / ml and 21,133.33 CFU / ml.
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Harrod, Victoria L., Russell L. Groves, Matthew A. Maurice, and Jeri D. Barak. "Frankliniella occidentalis facilitate Salmonella enterica survival in the phyllosphere." PLOS ONE 16, no. 2 (February 19, 2021): e0247325. http://dx.doi.org/10.1371/journal.pone.0247325.
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The human enteric bacterial pathogen Salmonella enterica causes approximately 1.35 million cases of food borne illnesses annually in the United States. Of these salmonellosis cases, almost half are derived from the consumption of fresh, raw produce. Although epiphytic S. enterica populations naturally decline in the phyllosphere, a subset of phytophagous insects have recently been identified as biological multipliers, consequently facilitating the growth of bacterial populations. We investigated whether tomato leaves with macroscopic feeding damage, caused by infestation of adult Western flower thrips (Frankliniella occidentalis), support higher S. enterica populations. To explore this hypothesis, we assessed S. enterica populations in response to thrips feeding by varying insect density, plant age, and the gender of the insect. As a reference control, direct leaf damage analogous to thrips feeding was also evaluated using directed, hydraulic pressure. In a supplementary set series of experiments, groups of F. occidentalis infested tomato plants were later inoculated with S. enterica to determine how prior insect infestation might influence bacterial survival and persistence. Following an infestation period, leaves visibly damaged by adult F. occidentalis supported significantly higher S. enterica populations and resulted in greater amounts of electrolyte leakage (measured as electrical conductivity) than leaves lacking visible feeding damage. Plant age did not significantly influence S. enterica populations or estimates of electrolyte leakage, independent of initial infestation. Additionally, the gender of the insect did not uniquely influence S. enterica population dynamics. Finally, applications of aggressive water bombardment resulted in more electrolyte leakage than leaves damaged by F. occidentalis, yet supported comparable S. enterica populations. Together, this study indicates that F. occidentalis feeding is one of the many potential biological mechanisms creating a more habitable environment for S. enterica.
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Landry, Carol L., and Beverly J. Rathcke. "Insect visitation rates and foraging patterns differ in androdioecious and hermaphrodite-only populations of Laguncularia racemosa (Combretaceae) in Florida." Journal of Tropical Ecology 28, no. 4 (June 1, 2012): 343–51. http://dx.doi.org/10.1017/s0266467412000296.
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Abstract:Insect-pollinated Laguncularia racemosa has a variable breeding system; some populations are androdioecious, with male and hermaphroditic plants, while others lack male plants. We observed the foraging behaviours of insects in three androdioecious and three hermaphrodite-only populations of L. racemosa in Florida. In each population, insect visitation rates were estimated from 30–108 timed intervals. We recorded the number of flowers visited by 144–224 insects during foraging bouts made to 15–40 male and hermaphroditic plants. Male plants in androdioecious populations had significantly more visitors than hermaphroditic plants, increasing the number of vectors carrying pollen from male plants. Further, many insects visited few flowers during foraging bouts, which should increase outcrossing frequency. According to mathematical models, male plants benefit from these combined factors. Plants in hermaphrodite-only populations had significantly more visitors than hermaphroditic plants in androdioecious populations. Proportionately more insects visited many flowers during foraging bouts in hermaphrodite-only versus androdioecious populations. The increased likelihood of geitonogamous self-pollination could help explain the lack of male plants in hermaphrodite-only populations. Differences in pollinator assemblages and the relative abundances of several species were responsible for differences in foraging behaviours: Apis mellifera, Bombus sp., Melissodes sp., Xylocopa sp., Euodynerus sp. and a calliphorid species.
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Baliota, Georgia V., Evagelia Lampiri, Evanthia N. Batzogianni, and Christos G. Athanassiou. "Insecticidal Effect of Four Insecticides for the Control of Different Populations of Three Stored-Product Beetle Species." Insects 13, no. 4 (March 25, 2022): 325. http://dx.doi.org/10.3390/insects13040325.
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The protection of stored products from insect pests is mainly based on suppressive methods by using contact and gaseous insecticides, globally. Following their continuous and improper use, insecticide resistance has been observed in several major insect species and pose a continuous threat to the sustainability of a wide range of active ingredients that are currently in use in stored product protection. In the present work, on-site samplings of insect populations were carried out in local warehouses containing different types of cereals. The collected insects, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) and Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), were reared under laboratory conditions to determine tolerance/resistance to widely used insecticides, using different diagnostic protocols. Laboratory populations of the same species were also examined for comparative purposes. Adult knock down and mortality of all populations indicated different patterns of tolerance to phosphine, deltamethrin, cypermethrin, and pirimiphos-methyl. In many cases, the recommended label doses were not able to completely control some of these populations, regardless of their origin, i.e., field-collected or laboratory. The results of the present work underline the importance of population on the efficacy of insecticides that are currently in use in stored product protection.
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Sewify, Gamal H., Maha S. Nada, and Anwar L. Bilgrami. "Entomophthorales Fungi Parasitizing Sucking Insects in Egypt." Asian Journal of Biology 20, no. 7 (June 11, 2024): 25–42. http://dx.doi.org/10.9734/ajob/2024/v20i7421.
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Entomophthorales are insect pathogenic fungi significant biological control potentials due to their high insect toxicity. This review focuses on the survey and morphological descriptions of entomophthoralean species attacking insect pests in Egypt. Until now 10 species of Entomophthorales fungi, belonging to three families (Entomophthoraceae, Neozygitaceae and Ancylistaceace) have been reported to suck insects as their hosts. These fungi are widely distributed in various climatic conditions in several Governorates, representing Lower and Upper Egypt. The fungi are the only pathogens that regularly and effectively control sucking insect populations in the natural ecosystems and agroecosystems. The present review emphasizes more studies and isolations of Entomophthorales species by using modern identification techniques so that their epidemiology and control potentials can be predicated on their role against insect pests under variable climatic conditions in Egypt. The possible relationship between population densities of sucking insect pests and Entomophthorales can be further studied to explore their effective applications under variable climatic conditions in the country.
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Chinnathambi, Rajivganthi, and Fathalla A. Rihan. "Analysis and control of Aedes Aegypti mosquitoes using sterile-insect techniques with Wolbachia." Mathematical Biosciences and Engineering 19, no. 11 (2022): 11154–71. http://dx.doi.org/10.3934/mbe.2022520.
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<abstract><p>Combining Sterile and Incompatible Insect techniques can significantly reduce mosquito populations and prevent the transmission of diseases between insects and humans. This paper describes impulsive differential equations for the control of a mosquito with Wolbachia. Several interesting conditions are created when sterile male mosquitoes are released impulsively, ensuring both open- and closed-loop control. To determine the wild mosquito population size in real-time, we propose an open-loop control system, which uses impulsive and constant releases of sterile male mosquitoes. A closed-loop control scheme is also being investigated, which specifies the release of sterile mosquitoes according to the size of the wild mosquito population. To eliminate or reduce a mosquito population below a certain threshold, the Sterile insect technique involves mass releases of sterile insects. Numerical simulations verify the theoretical results.</p></abstract>
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Ukuda-Hosokawa, Rie, Yasutsune Sadoyama, Misaki Kishaba, Takashi Kuriwada, Hisashi Anbutsu, and Takema Fukatsu. "Infection Density Dynamics of the Citrus Greening Bacterium “Candidatus Liberibacter asiaticus” in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants." Applied and Environmental Microbiology 81, no. 11 (March 27, 2015): 3728–36. http://dx.doi.org/10.1128/aem.00707-15.
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ABSTRACTHuanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, “CandidatusLiberibacter asiaticus,” and vectored by a phloem-sucking insect,Diaphorina citri. We investigated the infection density dynamics of “Ca. Liberibacter asiaticus” in field populations ofD. citriwith experiments using field-collected insects to address how “Ca. Liberibacter asiaticus” infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from “Ca. Liberibacter asiaticus”-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were “Ca. Liberibacter asiaticus” positive. The infections were systemic across head-thorax and abdomen, ranging from 103to 107bacteria per insect. In spring, the infection densities were low in March, at ∼103bacteria per insect, increasing up to 106to 107bacteria per insect in April and May, and decreasing to 105to 106bacteria per insect in late May, whereas the infection densities were constantly ∼106to 107bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with “Ca. Liberibacter asiaticus” infection densities in fieldD. citripopulations. Inoculation experiments with citrus seedlings using field-collected “Ca. Liberibacter asiaticus”-infected insects suggested that (i) “Ca. Liberibacter asiaticus”-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼106bacteria per insect) of “Ca. Liberibacter asiaticus” density inD. citriis required for successful transmission to citrus plants, and (iii)D. citriattaining the threshold infection level transmits “Ca. Liberibacter asiaticus” to citrus plants in a stochastic manner. These findings provide valuable insights into understanding, predicting, and controlling this notorious citrus pathogen.
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Grüning, Maren, Lukas Beule, Stephanie Meyer, Petr Karlovsky, and Anne I.-M.-Arnold. "The Abundance of Fungi, Bacteria and Denitrification Genes during Insect Outbreaks in Scots Pine Forests." Forests 9, no. 8 (August 14, 2018): 497. http://dx.doi.org/10.3390/f9080497.
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Outbreaks of defoliating insects may affect microbial populations in forests and thereby mass balances and ecosystem functioning. Here, we investigated the microbial dynamics in Scots pine (Pinus sylvestris L.) forests during outbreaks of the nun moth (Lymantria monacha L.) and the pine-tree lappet (Dendrolimus pini L.). We used real-time PCR (polymerase chain reaction) to quantify genes that characterize bacterial and fungal abundance and the denitrification processes (nirK, nirS, nosZ clades I and II) in different forest compartments and we analyzed the C and N content of pine needles, insect feces, larvae, vegetation layers, organic layers, and mineral soil horizons. The infestation of the nun moth increased the bacterial abundance on pine needles, in the vegetation layer, and in the upper organic layer, while fungal populations were increased in the vegetation layer and upper organic layer during both outbreaks. In soil, the abundance of nirK increased after insect defoliation, while the C/N ratios decreased. nosZ clades I and II showed variable responses in different soil layers and to different defoliating insects. Our results illustrate changes in the microbial populations in pine forests that were infested by defoliating insects and changes in the chemical soil properties that foster these populations, indicating a genetic potential for increased soil N2O emissions during the defoliation peak of insect outbreak events.
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Gols, Rieta, Gaylord A. Desurmont, and Jeffrey A. Harvey. "Variation in Performance and Resistance to Parasitism of Plutella xylostella Populations." Insects 10, no. 9 (September 11, 2019): 293. http://dx.doi.org/10.3390/insects10090293.
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Two major ecological factors determine the fitness of an insect herbivore: the ability to overcome plant resistance strategies (bottom-up effects) and the ability to avoid or resist attack by natural enemies such as predators and parasitoids (top-down effects). In response to differences in selection pressure, variation may exist in host-plant adaptation and immunity against parasitism among populations of an insect herbivore. We investigated the variation in larval performance of six different Plutella xylostella populations originating from four continents when feeding on a native Dutch plant species, Brassica rapa. One of the used populations has successfully switched its host plant, and is now adapted to pea. In addition, we determined the resistance to attack by the endoparasitoid Diadegma semiclausum originating from the Netherlands (where it is also native) and measured parasitoid performance as a proxy for host resistance against parasitism. Pupal mortality, immature development times, and adult biomass of P. xylostella differed significantly across populations when feeding on the same host plant species. In addition, parasitism success differed in terms of parasitoid adult emergence and their biomass, but not their development times. Variation among natural populations of insects should be considered more when studying interactions between plants and insects up the food chain.
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Rabelo, Marcelo M., Silvana V. Paula-Moraes, Eliseu Jose G. Pereira, and Blair D. Siegfried. "Demographic Performance of Helicoverpa zea Populations on Dual and Triple-Gene Bt Cotton." Toxins 12, no. 9 (August 28, 2020): 551. http://dx.doi.org/10.3390/toxins12090551.
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Insecticidal toxins from Bacillus thuringiensis (Bt) are valuable tools for pest management worldwide, contributing to the management of human disease insect vectors and phytophagous insect pests of agriculture and forestry. Here, we report the effects of dual and triple Bt toxins expressed in transgenic cotton cultivars on the fitness and demographic performance of Helicoverpa zea (Boddie)—a noctuid pest, known as cotton bollworm and corn earworm. Life-history traits were determined for individuals of three field populations from a region where H. zea overwintering is likely. Triple-gene Bt cotton cultivars that express Cry and Vip3Aa toxins killed 100% of the larvae in all populations tested. In contrast, dual-gene Bt cotton that express Cry1Ac+Cry1F and Cry1Ac+Cry2Ab allowed population growth with the intrinsic rate of population growth (rm) 38% lower than on non-Bt cotton. The insects feeding on Bt cotton plants that express Cry1Ac+Cry2Ab, Cry1Ac+Cry1F, or Cry1Ab+Cry2Ae exhibited reduced larval weight, survival rate, and increased development time. Additionally, fitness parameters varied significantly among the insect populations, even on non-Bt cotton plants, likely because of their different genetic background and/or previous Bt toxin exposure. This is the first report of the comparative fitness of H. zea field populations on dual-gene Bt cotton after the recent reports of field resistance to certain Bt toxins. These results document the population growth rates of H. zea from an agricultural landscape with 100% Bt cotton cultivars. Our results will contribute to the development and validation of resistance management recommendations.
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Manopo, Marsela Maria, Caroulus S. Rante, Reity A. G. Engka, and Tommy B. Ogie. "TYPES AND POPULATIONS OF INSECT PESTS IN RICE FIELDS (Oryza Sativa L.) IN MOGOYUNGGUNG VILLAGE, DUMOGA TIMUR DISTRICT, BOLAANG MONGONDOW REGENCY." Jurnal Agroekoteknologi Terapan 2, no. 2 (November 12, 2021): 53. http://dx.doi.org/10.35791/jat.v2i2.35313.
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Insects are one part of the biodiversity that exists on this earth. Insect species and populations have a very important impact on stability in the lowland rice ecosystem. The sedated insects are placed on white paper and then counted in numbers and put in a collection bottle containing alcohol and labeled on the bottle. The things that were observed were the type and population of insect pests. The results of observations of the types and populations of insect pests found in the village of Mogoyunggung District Dumoga Bolaang Mongondow district found 6 (six) types of insect pests. In the vegetative phase found 5 (five) types of insects namely Scotinophara coartata, Paraeucosmetus pallicornis, Sogatela furcifera, Oxya sp. and Scirpophaga innotata, while the generative phase of the insect species found were Leptocorisa oratorius, S. coartata, P. pallicornis, S. furcifera, and Oxya sp. Keywords: Diversity; insect; pests; Oryza sativa L AbstrakSerangga merupakan salah satu bagian dari keanekaragaman hayati yang ada dimuka bumi ini. Jenis dan populasi serangga memiliki dampak yang sangat penting bagi kestabilan di dalam ekosistem padi sawah. Indeks keanekaragaman dapat digunakan untuk menyatakan hubungan kelimpahan spesies dalam suatu komunitas. Penelitian bertujuan mengetahui jenis, populasi dan keanekaragaman serangga hama pada tanaman padi di Desa Mogoyunggung, Kecamatan Dumoga Timur, Kabupaten Bolaang Mongondow. Serangga yang telah terbius diletakkan pada kertas putih kemudian dihitung jumlahnya dan dimasukkan dalam botol koleksi yang berisi alkohol dan diberi label pada botol tersebut. Hal-hal yang diamati yakni jenis dan populasi serangga hama yang terjaring dalam net serangga. Hasil pengamatan jenis serangga hama di Desa Mogoyunggung Kecamatan Dumoga Kabupaten Bolaang Mongondow ditemukan 6 (enam) jenis serangga hama. Pada fase vegetatif ditemukan 5 (lima) jenis serangga yakni Scotinophara coartata (kepinding tanah), Paraeucosmetus pallicornis (kepik hitam), Sogatela furcifera (wereng punggung putih), Oxya sp. (belalang) dan Scirpophaga innotata (penggerek batang putih), sedangkan fase generatif jenis serangga yang ditemukan yaitu Leptocorisa oratorius (walang sangit), S. coartata (kepinding tanah), P. pallicornis (kepik hitam), S. furcifera (wereng punggung putih), dan Oxya sp. (belalang).Kata Kunci: Keanekaragaman; serangga; hama; Oryza sativa L.
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GEORGITIS, J., and R. REISMAN. "Venom skin tests in insect-allergic and insect-nonallergic populations." Journal of Allergy and Clinical Immunology 76, no. 6 (December 1985): 803–7. http://dx.doi.org/10.1016/0091-6749(85)90752-3.
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Palmersheim, Michala C., Roger Schürch, Megan E. O’Rourke, Jenna Slezak, and Margaret J. Couvillon. "If You Grow It, They Will Come: Ornamental Plants Impact the Abundance and Diversity of Pollinators and Other Flower-Visiting Insects in Gardens." Horticulturae 8, no. 11 (November 14, 2022): 1068. http://dx.doi.org/10.3390/horticulturae8111068.
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Gardening for pollinators and other flower-visiting insects, where ornamental landscaping plants are added to provide habitats and foraging resources, may provide substantial benefits to declining insect populations. However, plant recommendations often lack empirical grounding or are limited geographically. Here, we created a pollinator garden, replicated across two sites, that contained 25 ornamental landscape plants that were either native or non-native to mid-Atlantic states and perennial or annual. Our objective was to determine the plants that would bring insect abundance and diversity to gardens. We surveyed the number and taxonomy of insects visiting the plants for two summers. We found a significant effect of plant species on both the abundance and diversity of flower-visiting insects. Insects were 42 times more abundant on our most visited plant (black-eyed Susan, Rudbeckia fulgida) versus our least visited plant (petunia, Petunia sp.). There was more than one diversity point difference in the Shannon index between the plant with the most (purple coneflower, Echinacea purpurea) and least (verbena, Verbena bonariensis) diverse visitors. Across our plants, honey bee (Apis mellifera) abundance positively correlated with other insect pollinators, although not specifically with wild bee abundance. Native perennials outperformed non-native perennials and non-native annuals in insect abundance, and both non-native and native perennials attracted more diversity than non-native annuals. Across plants, diversity scores quadratically related to insect abundance, where the highest diversity was seen on the plants with medium abundance. Lastly, we present the weighted sums of all insect visitors per plant, which will allow future gardeners to make informed landscaping decisions. Overall, we have shown that gardening schemes could benefit from a data-driven approach to better support abundant and diverse insect populations within ornamental landscape gardens.
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Agrawal, Anurag A., Amy P. Hastings, Marc T. J. Johnson, John L. Maron, and Juha-Pekka Salminen. "Insect Herbivores Drive Real-Time Ecological and Evolutionary Change in Plant Populations." Science 338, no. 6103 (October 4, 2012): 113–16. http://dx.doi.org/10.1126/science.1225977.
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Insect herbivores are hypothesized to be major factors affecting the ecology and evolution of plants. We tested this prediction by suppressing insects in replicated field populations of a native plant, Oenothera biennis, which reduced seed predation, altered interspecific competitive dynamics, and resulted in rapid evolutionary divergence. Comparative genotyping and phenotyping of nearly 12,000 O. biennis individuals revealed that in plots protected from insects, resistance to herbivores declined through time owing to changes in flowering time and lower defensive ellagitannins in fruits, whereas plant competitive ability increased. This independent real-time evolution of plant resistance and competitive ability in the field resulted from the relaxation of direct selective effects of insects on plant defense and through indirect effects due to reduced herbivory on plant competitors.
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Markina, T. Y. "New approaches to quality control for cultures of insects for rearing." Biosystems Diversity 24, no. 1 (March 4, 2016): 164–72. http://dx.doi.org/10.15421/011620.
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An analytical review of existing methods of quality control for cultures of insects for rearing is presented. It is shown that there is a need to search for new approaches to solving this problem. The suggested methods for quality control for insect cultures are based on the rule of taxis intensity dependence on insect viability level. Testing of new methods of control and prediction of biological material viability was carried out on several breeds of silkworm (Bombyx mori L.) and a laboratory culture of the gypsy moth (Lymantria dispar L.). It was established that the caterpillars of silkworm breeds with high viability show higher chemotaxis intensity. It was found that intensity of taxis manifestation can be considered as a criterion of population condition. Selection of the most promising breeds of silkworm can be carried out at the moment of hatching without expensive rearing. It was shown that testing of neonate caterpillars by chemotaxis intensity provides the control of viability in all stages of insect development. Evaluation of chemotaxis intensity of adult males on female sex pheromone gives the possibility to select the specimens with the highest physiological properties for hybridization as well as to predict viability for progeny. The method of biological material selection by chemotaxis intensity was improved due to decrease the time of selection from 30 to 15 minutes and preliminary starvation of these insects. Positive correlation was evaluated between general viability of silkworm culture and intensity of chemotaxis of neonate larvae to the smell of mulberry leaf during 15 minutes after 12 hours of starvation. A significant increase of viability for silkworm breeds and hybrids was registered using such selection method during the spring and summer rearing. This selection method can be used also for assessment of culture viability. A new express-method of biological material selection for insect cultures establishment has been approbated. It is based on the positive correlation between insect viability parameters and their trophotaxis intensity. It is shown that for establishment of a laboratory culture of gypsy moth it is necessary to obtain the material from populations with the highest chemotaxis intensity. It was experimentally proved that parameters of chemotaxis intensity and insect viability reflect a certain level of population heterozygosity. The higher is the intensity of chemotaxis, the higher is the relative level of population heterozygosity. This fact gives the possibility to determine the level of heterozygosity for artificial insect populations by testing larvae for chemotaxis intensity. This method may be suitable for monitoring of natural populations condition in zones with intensive anthropogenic loading.
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Liu, Jinwen, Xiujuan Yan, Xinyuan Song, Jiamei Zhang, Donghui Wu, and Meixiang Gao. "Distribution characteristics of insect diversity in long-term fixed monitoring plots in Northeast China." PLOS ONE 16, no. 8 (August 18, 2021): e0250689. http://dx.doi.org/10.1371/journal.pone.0250689.
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The spatial patterns of field arthropod communities are an essential part of ecology and can provide fundamental data regarding field ecological processes and reveal the mechanism of ecosystem biodiversity maintenance. This study investigated the spatial distribution pattern of field insect communities to detect the spatial relationships between insect communities in farmland. The study site was located at the Dehui Agro-ecological Experimental Station of Black Soil, Jilin, China. Insect communities and environmental factors were sampled at 121 uniformly distributed points in a 400 × 400 m plot in August, September, and October 2015. The analysis revealed that insect communities from June to October demonstrated significant spatial correlation, and 6085 samples of 47 species and 47 families in 11 orders were collected from the insect community in the farmland. The farmland insect community structure changes and dynamic changes of nutritional function groups occur with time. According to the 400 x 400 m plot, the diversity of farmland insect communities and functional groups is maintained at a relatively high and stable level. In this study, a total of 6085 samples of corn farmland insects were obtained using the fluke method and direct observation method, including 11 orders, 26 families and 47 species, 4 absolute dominant populations, 6 main dominant populations, and 37 other populations. These studies can provide help for pest control in the spring corn area of Northeast China.
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Ben Dhahbi, Anis, Yassine Chargui, Salah Mahmoud Boulaaras, Sana Ben Khalifa, Waleed Koko, and Faisal Alresheedi. "Mathematical Modelling of the Sterile Insect Technique Using Different Release Strategies." Mathematical Problems in Engineering 2020 (November 6, 2020): 1–9. http://dx.doi.org/10.1155/2020/8896566.
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We study simple mathematical models for the dynamics of interactive wild and sterile insect populations. As well as being mathematically tractable, these models can be used as first approximations to real situations occurring with the Sterile Insect Technique (SIT) in which sterile males are released to reduce or eradicate a pest population. This is a method of biological control which can effectively help contain the spread of many pest insects such as the Red Palm Weevil (RPW). Models formulated in this paper are continuous-time, include a strong Allee effect that captures extinction events, and incorporate different strategies of releasing sterile insects. We perform basic studies of dynamical features of these models, with an emphasis on the condition of excitation, and the impact of the different release methods is investigated. Our findings are also demonstrated with some numerical examples.
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Castro, Mauricio, and Edgar Chambers. "Consumer Avoidance of Insect Containing Foods: Primary Emotions, Perceptions and Sensory Characteristics Driving Consumers Considerations." Foods 8, no. 8 (August 17, 2019): 351. http://dx.doi.org/10.3390/foods8080351.
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Why do many human beings find bugs repulsive? Disgust, a psychological factor, is believed to be the main reason why consumers would not consider eating foods containing insect ingredients. This study aimed to understand specific consumers’ behaviors toward insect based products. A global survey was launched in 13 different countries. The participants (n = 630 from each country) completed the survey that included demographic questions and questions about why they would or would not eat insect-based products. The results show, particularly for some of the Asian countries, that it is necessary to start exposing and familiarizing the populations about insects in order to diminish the disgust factor associated with insects. It is strongly recommended that an insect-based product should not contain visible insect pieces, which trigger negative associations. The exceptions were consumers in countries such as Mexico and Thailand, evaluated in this study, which did not show significant negative beliefs associated with including insects in their diets. Additional research to promote insect-based product consumption with popular product types might be the first strategy to break the disgust barriers and build acquaintance about insect-based products. The need to educate consumers that not all insects are unhygienic is crucial to eliminating the potentially erroneous concepts from consumer mindsets.
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Amir, Rahmat Thabrani Ashari, Humairah Madani, and Resky Aqriani. "Insect pests population of stored maize in four regencies of South Sulawesi." IOP Conference Series: Earth and Environmental Science 1230, no. 1 (September 1, 2023): 012112. http://dx.doi.org/10.1088/1755-1315/1230/1/012112.
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Abstract Information on species, insect pest populations that attack and storage conditions determines the control strategy. This study aims to determine the various types of post-harvest pest s population in maize kernels stored in four in South Sulawesi. Identification of post-harvest insect pests at the Pest Laboratory, Department of Plant Pests and Diseases, Faculty of Agriculture, University of Hasanuddin Makassar. Sampling using the direct capture method (hand sampling) and manual instruments. Sampling was carried out by taking samples of corn kernels in sacks from five points and taking samples of the corn kernels that were scattered on the floor of the warehouse. The results showed that 10 spesies of insects were found including 9 spesies of pests namely Sitophilus sp. Cryptolestes ferrugineus, Corcyra cephalonica, Carpophilus sp, Araecerus fasciculatus, Lophocateres pusillus, Rhyzopertha dominca, Tribolium castaneum and Oryzaephilus surinamensis and one species of parasitoid :Anisopteromalus calandrae. Sitophilus sp. is the most common species found in all districts with a total population of 636 individuals then Cryptolestes ferrugineus with 53 individuals and T. castaneum with 37 individuals. Post-harvest pest populations in all districts were found more commonly around 73% in piles of sacks compared to populations found in spilage commodities, namely around 27%.