Levels Of Parasitism Research Articles

Automated Life Stage Classification of Malaria Using Deep Learning

INTRODUCTION: Malaria, an infectious illness spread by mosquitoes, is a serious hazard to humans and animals, with an increasing number of cases recorded yearly. Prompt and precise diagnosis, as well as preventative actions, are critical for effectively combating this condition. Malaria is now diagnosed using standard techniques. Microscopy of blood smears, which consists of small pictures, is used by trained specialists to identify diseased cells and define their life phases. The World Health Organisation (WHO) has approved this microscopy-based malaria diagnostic method. Drawing a blood sample from the finger, pricking it, spreading it onto a clean glass slide, and allowing it to dry naturally are all steps in the method. Thin blood smears were previously used to identify parasites under the microscope, but thick blood smears are utilized when parasite levels are low. OBJECTIVES: Due to its reliance on medical knowledge, high prices, time-consuming nature, and unsatisfactory outcomes, this technique has significant disadvantages. However, as deep learning algorithms progress, these activities may be completed more effectively and with fewer human resources. METHODS: This study demonstrates the usefulness of transfer learning, a type of deep learning, in categorizing microscopic pictures of parasitized versus uninfected malaria cells. Six models were evaluated using the publicly accessible NIH dataset, proving the usefulness of the suggested technique. RESULTS: VGG19 model fared better than its competitors, obtaining 95.05% accuracy, 92.83% precision, 96.88% sensitivity, 93.46% specificity, and 94.81% F1-score. CONCLUSION: This categorization of malaria cell photos will benefit microscopists in particular, as it will improve their workflow and provide a viable alternative for detecting malaria using microscopic cell images.

Biotic resistance towards Hydrellia egeriae, a biological control agent for the aquatic weed Egeria densa, in South Africa

Egeria densa is a submerged aquatic weed that can grow into dense monocultures in rivers and dams in South Africa, which negatively affects ecosystem functioning and services. The biological control agent Hydrellia egeriae Rodrigues-Júnior (Diptera: Ephydridae) was first released against Egeria densa Planchon (Hydrocharitaceae) in South Africa in 2018. Biotic resistance in an introduced range can have negative impacts on the ability of a biological control agent to establish and exert top-down pressure. Dipteran and lepidopteran species that are used as biological control agents are often susceptible to higher levels of parasitism in their introduced range than biological control agents from other insect orders. In addition, ecological analogues that are present in South Africa, make H. egeriae particularly vulnerable to biotic resistance. Considering this, post-release surveys were conducted to investigate if native parasitoids will extend their host range to include H. egeriae. Chaenusa seminervata van Achterberg, C. anervata van Achterberg (Braconidae: Alysiinae: Dacnusini) and Ademon lagarosiphonae van Achterberg (Braconidae: Opiinae) were reared from field-collected H. egeriae pupae, within a year of its release. These braconid parasitoids were previously recorded from a native herbivore, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae). Parasitism levels of H. egeriae ranged from 50 to 74% in cold months and 0 to 60% in warmer months, with higher levels of parasitism at a site where H. lagarosiphon naturally occurs. This study also found that cumulative release events of the biological control agent increase the probability of parasitism of field populations, by directly increasing the host pool. However, biological control efficacy can potentially be increased by limiting release efforts to a maximum of two release events per site per season, with particular focus on releasing in warm (i.e. spring/summer) months. Continued post-release surveys are necessary to not only monitor H. egeriae’s impact on E. densa, but also to obtain a better understanding of seasonal parasitism levels across E. densa-invaded sites in South Africa.

Effect of Environmental Factors on Strepsipteran Parasite Abundance in Vespine Wasps (Hymenoptera: Vespidae)

Xenos is a strepsipteran genus parasitizing hornets of the Vespa spp. In Japan, parasitism levels in hornets have been examined for two Xenos species. These studies have indicated that parasitism levels vary with the seasons but are inconsequential compared to other potential factors that reduce the number of host colonies. However, a comprehensive analysis of parasitism levels accounting for various factors such as host species, seasons, and years was not conducted. To address this gap, we conducted a four-year study in which we collected Vespa spp. using bait traps and assessed parasitism levels concerning those factors. Additionally, we evaluated the number of male and female Xenos parasites throughout the seasons. A total of 11,766 wasps from six hornet species were collected, with three of the species conspicuously parasitized by two Xenos parasites: Vespa analis (Fabricius, 1775) parasitized by Xenos oxyodontes (Nakase & Kato, 2013) and Vespa mandarinia (Smith, 1852) and Vespa ducalis (Smith, 1852) parasitized by Xenos moutoni (Buysson, 1903). Levels of parasitism by X. oxyodontes exceeded those by X. moutoni. Seasonal and yearly variations influenced the levels of parasitism by the two Xenos spp. We observed that male and female Xenos parasites emerged simultaneously over 2 – 3 months, suggesting the likelihood of multivoltinism in temperate regions. Our study also examined several key factors influencing the fluctuations in the population size of these parasites.

74 Effect of grazing native warm season grasses on parasitism and growth in weaned Katahdin lambs

Abstract Parasitism in lambs during the post-weaning period has effects on growth, survival, and sheep enterprise profitability. Opportunities to minimize exposure to infective larvae during this period may reduce clinical effects and improve lamb performance. Native warm season grasses (NWSG) offer increased growth during summer months and taller plants that allow grazing at greater heights. The objective here was to evaluate NWSG as a forage for post-weaning development of lambs in spring lambing, forage-based systems. Over 2 yr, Katahdin lambs (Yr 1, n = 30; Yr 2, n = 31) were managed at a producer farm in the piedmont region of North Carolina. Beginning 2 wk post-weaning, lambs were randomly assigned to graze on either NWSG (Big Bluestem and Indiangrass) or cool season grass (CSG, Kentucky 31 Tall Fescue base) pasture. Lambs were continuously grazed for 70 d in Yr 1 and 55 d in Yr 2. Fecal egg count (FEC), FAMACHA score, and body weight (BW) were measured every two weeks. Lambs were dewormed at FAMACHA ≥ 3. Forage analysis was conducted at the start and end of the grazing period. Statistical analysis were performance using the PROC Mixed procedure of SAS. Lambs in each group were raised in similar litter sizes and sire and sex were evenly distributed between groups. Fecal egg count and growth estimated breeding values (EBV) were similar between NWSG and CSG groups. In Yr 1 and 2, no differences were observed in FEC between grazing groups (P > 0.05). However, FEC did increase in both groups throughout the grazing period (P < 0.05). In Yr 1, no differences were observed in total BW gain (P = 0.74). However, in Yr 2, lambs grazing CSG had greater total BW gain than the NWSG group (P < 0.05). In both years, there were no differences in the percentage of lambs requiring deworming (Yr 1, P = 0.36; Yr 2, P = 0.47) but lambs requiring treatment had greater FEC EBVs (P < 0.05). Nutrient quality of NWSG pasture was reduced compared with CSG pastures. Total digestible nutrients and crude protein were less in NWSG compared with CSG pastures (Yr 2: 61.5% vs. 63.9% and 8.9% vs. 13.6%, respectively) and neutral detergent fiber was greater (Yr 2: 74.1% vs. 65.2%, respectively) resulting in decreased nutrient availability for NWSG group. While NWSG may provide additional biomass for summer grazing, rapid maturity rates may limit nutrient availability for lambs resulting in decreased growth performance despite similar levels of parasitism. Lamb FEC EBV may have a role in parasite resistance and deworming requirements regardless of forage type. Thus, genetics must be considered along with grazing management as part of an integrated parasite management plan.

A conserved trypanosomatid differentiation regulator controls substrate attachment and morphological development in Trypanosoma congolense.

Trypanosomatid parasites undergo developmental regulation to adapt to the different environments encountered during their life cycle. In Trypanosoma brucei, a genome wide selectional screen previously identified a regulator of the protein family ESAG9, which is highly expressed in stumpy forms, a morphologically distinct bloodstream stage adapted for tsetse transmission. This regulator, TbREG9.1, has an orthologue in Trypanosoma congolense, despite the absence of a stumpy morphotype in that parasite species, which is an important cause of livestock trypanosomosis. RNAi mediated gene silencing of TcREG9.1 in Trypanosoma congolense caused a loss of attachment of the parasites to a surface substrate in vitro, a key feature of the biology of these parasites that is distinct from T. brucei. This detachment was phenocopied by treatment of the parasites with a phosphodiesterase inhibitor, which also promotes detachment in the insect trypanosomatid Crithidia fasciculata. RNAseq analysis revealed that TcREG9.1 silencing caused the upregulation of mRNAs for several classes of surface molecules, including transferrin receptor-like molecules, immunoreactive proteins in experimental bovine infections, and molecules related to those associated with stumpy development in T. brucei. Depletion of TcREG9.1 in vivo also generated an enhanced level of parasites in the blood circulation consistent with reduced parasite attachment to the microvasculature. The morphological progression to insect forms of the parasite was also perturbed. We propose a model whereby TcREG9.1 acts as a regulator of attachment and development, with detached parasites being adapted for transmission.

Pyridoxal kinase gene deletion leads to impaired growth, deranged redox metabolism and cell cycle arrest in Leishmania donovani

Pyridoxal kinase (PdxK) is a vitamin B6 salvage pathway enzyme which produces pyridoxal phosphate. We have investigated the impact of PdxK deletion in Leishmania donovani on parasite survivability, infectivity and cellular metabolism. LdPdxK mutants were generated by gene replacement strategy. All mutants showed significant reduction in growth in comparison to wild type. For PdxK mediated biochemical perturbations, only heterozygous mutants and complementation mutants were used as the growth of null mutants were compromised. Heterozygous mutant showed reduction invitro infectivity and higher cytosolic and mitochondrial ROS levels. Glutathione levels decreased significantly in heterozygous mutant indicating its involvement in cellular oxidative metabolism. Pyridoxal kinase gene deletion resulted in reduced ATP levels in parasites and arrest at G0/G1 phase of cell cycle. All these perturbations were rescued by PdxK gene complementation. This is the first report to confirm that LdPdxK plays an indispensable role in cell survival, pathogenicity, redox metabolism and cell cycle progression of L. donovani parasites. These results provide substantial evidence supporting PdxK as a therapeutic target for the development of specific antileishmanial drug candidates.

Pierid Butterflies, Legume Hostplants, and Parasitoids in Urban Areas of Southern Florida.

Are parasitoids less likely to find their Lepidoptera hosts on non-native hostplants than native hostplants? We predicted that with longer periods of coevolution between herbivores and the plants they consume, the parasitoids that provide top-down control would be more attuned to finding their hosts on native plants. To test this hypothesis, we collected immature stages of sulfur butterflies (the cloudless sulfur (Phoebis sennae) and the orange-barred sulfur (Phoebis agarithe) over a three-year period (2008-2011) from native and ornamental hostplants in the genus Senna in three different parts of the urban landscape of Miami, Florida, USA. We reared the immature specimens to pupation and either eclosion of adults or emergence of parasitoids and compared the levels of parasitization among the three areas, and among native vs. exotic hostplants. We found, contrary to our prediction, that caterpillars feeding on non-native leguminous hostplant species were more likely to be parasitized than those feeding on native hostplants. We discuss this surprising finding in the light of recent findings in other plant/herbivore/parasitoid systems.

Host-instar selection, interspecific competition, and reproductive capacity of extant and novel parasitoids (Hymenoptera: Braconidae) on Egyptian cotton leafworm

Abstract Background Cotesia marginiventris (Cresson) and Microplitis rufiventris Kok. (Hymenoptera: Braconidae) are larval endoparasitoids of Spodoptera frugiperda (Smith) and S. littoralis (Boisd.), respectively. Cotesia marginiventris was introduced in Egypt to control the recent invasive pest, S. frugiperda and local one, S. littoralis. Therefore, competition between the two parasitoid species may occur. Results When single females of C. marginiventris (Exp. 1), single females of M. rufiventris (Exp. 2), and one female each of C. marginiventris and M. rufiventris (Exp. 3) were offered a choice of 60 1st, 60 2nd, and 60 3rd instars, of the tested host species, S. littoralis and different parasitization levels were obtained. In the non-competitive context (Exps. 1, 2), all instars were parasitized, but C. marginiventris and M. rufiventris parasitized primarily 2nd and 3rd instar host larvae, respectively. In the competitive context (Exp. 3), the same preference pattern emerged but the percentage of parasitism was lower than in each of the two non-competitive contexts. Conclusions M. rufiventris appears to be a superior competitor when simultaneously exploiting the host with the other parasitoid species. The knowledge of this work can be used to predict and/or understand possible outcomes of a biological control program using the two biocontrol agents against one or the two pests species, and to gain insight into possible biotic interference between species at the same trophic level exploiting the same host. Graphical abstract

Distinct transcriptomic signatures define febrile malaria depending on initial infective states, asymptomatic or uninfected

BackgroundCumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate the maintenance of chronic symptomless infections that sustain malaria transmission.MethodsHere, we determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children (< 15 years). We compared children who were defined as uninfected, asymptomatic and those with febrile malaria.ResultsChildren with asymptomatic infections had a parasite transcriptional profile characterized by a bias toward trophozoite stage (~ 12 h-post invasion) parasites and low parasite levels, while early ring stage parasites were characteristic of febrile malaria. The host response of asymptomatic children was characterized by downregulated transcription of genes associated with inflammatory responses, compared with children with febrile malaria,. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses.ConclusionsThe priming effect of prior asymptomatic infection may explain the blunted acquisition of antibody responses seen to malaria antigens following natural exposure or vaccination in malaria endemic areas.

Assessing the sub‐lethal impacts of insecticides on aphid parasitoids through laboratory‐based studies

AbstractAphids are a major pest of cropping systems throughout the world. In most cases, crop aphids are controlled with broad‐spectrum insecticides; although generally very effective at preventing yield loss, this approach risks non‐target damage to beneficial organisms. In the last 20 years, a number of selective insecticides have become available to control aphids while minimising harm to other arthropods. Previous studies have found that two such insecticides, flonicamid and afidopyropen, cause only low‐level acute mortality impacts on aphid parasitoids in Australian grain crops. However, little research has examined the sub‐lethal effects of these chemicals, which could induce various physiological changes that impact pest control. We hypothesised that both flonicamid and afidopyropen have negative effects that extend beyond the immediate acute mortality previously published. To test this hypothesis, we undertook a series of experiments to determine the effects of flonicamid and afidopyropen, along with the synthetic pyrethroid gamma‐cyhalothrin, on aphid parasitism (mummification) rate, emergence rate of the next generation and the next generation sex ratio in three important aphid parasitoids, Aphidius colemani (Viereck), Diaeretiella rapae (M'Intosh) and Aphelinus abdominalis (Dalman). Analogous with previous research, our acute toxicity bioassays showed that all three insecticides had low (&lt;30%) mortality impacts. Although sub‐lethal impacts could not be assessed for D. rapae due to the low level of aphid parasitism by that species, our findings showed negative impacts on fecundity in surviving A. abdominalis and A. colemani. Of particular note is the increase in International Organisation for Biological Control ratings to moderate (30%–80% mortality and/or reproductive reduction) when mortality and reduced fecundity effects were combined to determine overall fitness impacts. Gamma‐cyhalothrin typically resulted in higher negative impacts on A. abdominalis and A. colemani (compared with flonicamid and afidopyropen); however, quite surprisingly, these impacts were not rated as highly toxic. Taken together, our results suggest that, even when sub‐lethal impacts are considered, flonicamid and afidopyropen are useful tools for farmers targeting aphid populations while minimising the non‐target impacts on parasitoids. We recommend semi‐field and/or field trials to further assess the impacts of these insecticides on aphid parasitoid populations.

Parasite assemblages of lanternfishes (Myctophidae) in deep subantarctic waters: Potential indicators for ecosystem monitoring

The Agujero Azul (Blue Hole) is an oceanic region located on the edge of the Southwestern Atlantic continental shelf that is especially impacted by intense fishing activity. It harbours a high biodiversity, including the mesopelagic lanternfishes of the numerically abundant family Myctophidae. Due to their high abundance and relevance in food webs, monitoring changes in the population and community structure of mesopelagic fishes is a valuable tool to trace changes in a warming world, especially in a highly exploited ecosystem where the effects of global change have been documented. Parasite communities of the lanternfishes Gymnoscopelus nicholsi and Electrona subaspera, caught at the Agujero Azul are analyzed. The aims of this work were to assess their value as indicators of host population structure and to establish a baseline for monitoring ecosystem variations under future scenarios of global change. The connectivity with the population of G. nicholsi from around South Georgia was also evaluated by comparing their parasite faunas. A parasitological study of 170 G. nicholsi and 31 of E. subaspera showed low parasite abundance and species richness, with significantly higher levels of parasitism in larger fishes. The paucity of parasitism in G. nicholsi from South Georgia compared to Agujero Azul suggests the existence of two discrete stocks. On the other hand, comparison with literature data supports a connection between fish from the Patagonian shelf and South Shetland Islands (Antarctica). Comparison across samples from Agujero Azul showed homogeneity in parasite assemblages, regardless of the distance separating them, ensuring that parasites are reliable representatives of such physical conditions. Thus, this representability suggests that parasites can be suitable indicators to estimate the amplitude of future changes due to global warming and other anthropogenic stressors in this region. This work provides a baseline for using the parasites of G. nicholsi as indicators to trace these ongoing and predicted changes.

Assessing Natural Incidence of Resident Pupal Parasitoids on the Drosophila suzukii (Diptera: Drosophilidae) Population in Non-crop Fruits.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), world-renowned as spotted-wing drosophila, is an invasive pest mainly affecting healthy, soft and stone fruit crops throughout Argentinian fruit-growing regions. Natural environments overgrown by exotic feral host plants apparently favour D. suzukii proliferation. This is common in the subtropical northwestern Argentina's berry-producing region. An assemblage of resident parasitoid species has been associated with D. suzukii in crop and non-crop areas of Tucumán, the Argentina's leading berries producer and exporter. Consequently, the hypothesis that the combined action of two pupal parasitoid species, Pachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) and Trichopria anastrephae Lima (Hymenoptera: Diapriidae), occurring in non-crop fruit areas, has a significant impact on D. suzukii natural regulation in such invaded habitats was tested. A survey of D. suzukii puparia from both feral peach [Prunus persica (L.) Batsch] (Rosaceae) and guava (Psydium guajava L.) (Myrtaceae) fallen fruits and soil surrounding them was performed in a wilderness area of Tucumán. Abundance of D. suzukii and associated parasitoids, and parasitism levels were assessed. Whole of 3437 D. suzukii puparia were recovered; 78% and 22% were surveyed from fruits and soil underneath the fruit, respectively. Tested fruits are important D. suzukii multiplying hosts. Both P. vindemiae and T. anastrephae accounted for 99.8% of total parasitoid individuals. Pupal parasitoids contribute to the D. suzukii natural mortality, as they killed a quarter of all puparia. Mostly T. anastrephae foraged on host puparia located in the fruit and P. vindemiae in both microhabitats. This information supports an augmentative biological control strategy in non-crop areas.

Too much information? Males convey parasite levels using more signal modalities than females utilise.

Elaborate sexual signals are thought to have evolved and be maintained to serve as honest indicators of signaller quality. One measure of quality is health, which can be affected by parasite infection. Cnemaspis mysoriensis is a diurnal gecko that is often infested with ectoparasites in the wild, and males of this species express visual (coloured gular patches) and chemical (femoral gland secretions) traits that receivers could assess during social interactions. In this paper, we tested whether ectoparasites affect individual health, and whether signal quality is an indicator of ectoparasite levels. In wild lizards, we found that ectoparasite level was negatively correlated with body condition in both sexes. Moreover, some characteristics of both visual and chemical traits in males were strongly associated with ectoparasite levels. Specifically, males with higher ectoparasite levels had yellow gular patches with lower brightness and chroma, and chemical secretions with a lower proportion of aromatic compounds. We then determined whether ectoparasite levels in males influence female behaviour. Using sequential choice trials, wherein females were provided with either the visual or the chemical signals of wild-caught males that varied in ectoparasite level, we found that only chemical secretions evoked an elevated female response towards less parasitised males. Simultaneous choice trials in which females were exposed to the chemical secretions from males that varied in parasite level further confirmed a preference for males with lower parasites loads. Overall, we find that although health (body condition) or ectoparasite load can be honestly advertised through multiple modalities, the parasite-mediated female response is exclusively driven by chemical signals.

A method for sampling parasitized Drosophila suzukii (Diptera: Drosophilidae) puparia from soil.

Methods to measure the diversity and biological control impact of parasitoids for the control of spotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) are being developed in support of biological control programs around the world. Existing methods to determine parasitism levels and parasitoid species composition focus on sampling D. suzukii within fresh and rotting fruit. However, many D. suzukii pupate in the soil or in dropped fruit, where additional parasitism could occur and where their parasitoids are thought to overwinter. Here we introduce a method for extracting parasitized D. suzukii puparia from the soil through a sieve and flotation system, allowing for effective collection of puparia, from which parasitoids can then be reared. Although the method considerably underestimates the absolute number of puparia in soil samples, it nonetheless yields a high number of puparia relative to sampling effort and provides a robust estimate of the relative abundance of puparia among samples. Using this method, we confirmed that at least 5 species of parasitoids, including some that have rarely been detected in past studies, overwinter in their immature stages inside D. suzukii puparia in south coastal British Columbia, Canada. The ability to sample puparia from the soil will lead to a more comprehensive view of both D. suzukii and parasitoid abundance throughout the season, help confirm parasitoid establishment following intentional releases, and provide a way to measure the diversity of parasitoid species and potential interactions among parasitoids (e.g., hyper- or klepto-parasitism) that may often occur on the soil surface.

Fundamental limits of parasitoid-driven host population suppression: Implications for biological control.

Parasitoid wasps are increasingly being used to control insect pest populations, where the pest is the host species parasitized by the wasp. Here we use the discrete-time formalism of the Nicholson-Bailey model to investigate a fundamental question-are there limits to parasitoid-driven suppression of the host population density while still ensuring a stable coexistence of both species? Our model formulation imposes an intrinsic self-limitation in the host's growth resulting in a carrying capacity in the absence of the parasitoid. Different versions of the model are considered with parasitism occurring at a developmental stage that is before, during, or after the growth-limiting stage. For example, the host's growth limitation may occur at its larval stage due to intraspecific competition, while the wasps attack either the host egg, larval or pupal stage. For slow-growing hosts, models with parasitism occurring at different life stages are identical in terms of their host suppression dynamics but have contrasting differences for fast-growing hosts. In the latter case, our analysis reveals that wasp parasitism occurring after host growth limitation yields the lowest pest population density conditioned on stable host-parasitoid coexistence. For ecologically relevant parameter regimes we estimate this host suppression to be roughly 10-20% of the parasitoid-free carrying capacity. We further expand the models to consider a fraction of hosts protected from parasitism (i.e., a host refuge). Our results show that for a given host reproduction rate there exists a critical value of protected host fraction beyond which, the system dynamics are stable even for high levels of parasitism that drive the host to arbitrary low population densities. In summary, our systematic analysis sheds key insights into the combined effects of density-dependence in host growth and parasitism refuge in stabilizing the host-parasitoid population dynamics with important implications for biological control.

Landscape complexity effects on Brassicogethes aeneus abundance and larval parasitism rate: a two-year field study

Global biodiversity has suffered a decline primarily attributed to landscape simplification and intensified agricultural practices. Agricultural environments, characterized by homogeneity and frequent disturbances, are often suboptimal habitats for various insect species. While agricultural fields do favour pests, they generally fail to provide suitable habitats for natural enemies. The inclusion of diverse supporting habitats, such as semi-natural habitats, grassy and woody field margins etc. surrounding agricultural fields, play a crucial role in fostering effective biodiversity conservation. Moreover, determining the influence of different adjacent habitat types is essential in elucidating their influence on pest abundance and parasitism rates. Our two-year field study focused on assessing the abundance of Brassicogethes aeneus and its parasitism rate. The findings revealed that the adjacent habitat type did not significantly increase pest abundance and the parasitism rate of B. aeneus larvae consistently stayed over the threshold for effective biological control throughout the fields. This was attributed to the high proportion (35 and 38% in the 2 study years) of semi-natural habitats within most of the 1 km radius study areas. While our study did not identify any specific adjacent habitat type or habitat within a 1 km radius that directly impacted B. aeneus abundance, it emphasises the intricate interplay between the pests, parasitism and the surrounding environment because the interactive effect of distance from the crop edge and habitat type had a significant influence on B. aeneus infestation levels but not on parasitism. Decision tree analysis suggests that > 18% semi-natural habitat is needed to ensure sufficient levels of parasitism for effective biological control. A comprehensive understanding of habitats that influence not only B. aeneus but also other pests is critical for the successful implementation of IPM strategies and conservation initiatives within the agricultural sector.

Natural Control of Sugarcane Top Borer Scirpophaga excerptalis Walker (Crambidae: Lepidoptera) by Its Egg Parasitoids

The sugarcane shoot borer (Scirpophaga excerptalis) is an herbivorous insect that primarily infests sugarcane plants, leading to the development of dead heart symptoms. This study aimed to investigate the contribution of egg parasitoids in mitigating the occurrence of dead heart caused by S. excerptalis infestation. The research was conducted in Asembagus and Malang, East Java, Indonesia. The samples collection of shoot borer eggs were done twice in Asembagus, and three times in Malang. The collected eggs were examined to determine the percentage of parasitism, and the emerged parasitoids were identified. The infestation level of shoot borers was evaluated by counting the dead heart symptoms within 5 m2 observation units, comprising 18 and 15 units in Asembagus and Karangploso, respectively. Three species of parasitoids, namely Telenomus sp., Trichogramma chilonis, and Tetrastichus sp., were found to parasitize S. excerptalis eggs. The average parasitism levels by Telenomus sp., T. chilonis, and Tetrastichus sp. were 74% (ranged: 50-100%), 0.6% (ranged: 0-4.4%), and 14.3% (ranged: 0-100%), respectively. Telenomus sp. was the predominant egg parasitoid observed in all observations at both sites. There was an inverse relationship between the mortality of shoot borer eggs by parasitoids and the occurrence of dead heart symptoms. Higher levels of parasitism were associated with reduced dead shoot symptoms. The natural control of S. excerptalis through the complex of egg parasitoids holds a promise for effective management of sugarcane shoot borers and promoting sustainable agriculture.

Role of Mermithid Nematodes in the Management of Agricultural and Household Insect Pests: A review

The increasing challenges associated with using chemicals in managing agricultural and household insect pests has prompted a re-evaluation of previous approaches and the search for new ones as alternatives or supplements to the present management programmes. The introduction and release of bio-agents, like fungi, bacteria, viruses, nematodes, and insects for the control of pests is a novel biological control strategy. Among bio-agents, the role of mermithid nematodes in insect-pest management has been considered. Mermithids are prime candidates for biocontrol of insects due to their adaptability to the life cycle of the host, a high degree of host specificity often limited to one or more species of insects, high reproductive potential, free swimming behavior making dissemination of pre-parasitic stage easy, pathogenic ability and high levels of parasitism. Another useful trait favoring their employability is their non-feeding habit soon after emerging from the host body, making their handling simple. The morphological, physiological, and behavioral responses of host insects are significantly disrupted by mermithid infective juveniles often the J2 stage. Many mermithid infections cause abdominal distortion, discolored cuticle/integument, and a decrease in total fat body content of the host. The parasitism by these nematodes can lead to formation of intersexual conditions in the host insects which also create distortion to endocrine system. Owing to such mechanism of parasitism of mermithids, these nematodes are one the best considerations as bio-control agents.

Volatile blooms of Aleurodicus rugioperculatus Martin infested coconut and banana leaves attracting parasitoid Encarsia guadeloupae Viggiani

Invasive whitefly species in coconut plantations have become a matter of concern in the last half a decade as they cause direct and indirect infestation on the palms. The Rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin infestation was high on Cocos nucifera L. (coconut) followed by Dypsis lutescens (H. Wendl.) (Butterfly palm) and Annona squamosa L. (custard apple). The coconut varieties Malayan Yellow Dwarf and Chowghat Orange Dwarf were observed with higher infestation index while that of West coast tall was the lowest. Higher RSW parasitization levels were observed on Musa paradisiaca L. (banana) and Canna indica L. (Indian shot), with 85.96 and 71.59% parasitization, respectively. Identification of volatile organic compounds (VOCs) between healthy and RSW-infested coconut plants revealed the emission of 56 VOCs from the healthy coconut plant and 47 VOCs from RSW infested plant. 22 VOCs were common in both samples, and 25 VOCs were unique to RSW-infested coconut plants. The presence of 42 VOCs was identified from the headspace extracts of RSW-infested bananas. Differences in the VOCs emitted from RSW-infested banana and coconut plants revealed higher emission of terpenoids like β-Caryophyllene, (E, Z)-2,6-dimethyl-2,4,6-Octatriene, Humulene, α-Pinene, Farnesane, α-Copaene and β-cis-Ocimene from RSW infested banana plants that proved to be more attractive to the parasitoid. Identifying specific blends of volatile compounds influencing Encarsia guadeloupae Viggiani could help to augment the parasitotic for RSW management in coconut plantations.

IMAGING: a novel automated system for malaria diagnosis by using artificial intelligence tools and a universal low-cost robotized microscope

IntroductionMalaria is one of the most prevalent infectious diseases in sub-Saharan Africa, with 247 million cases reported worldwide in 2021 according to the World Health Organization. Optical microscopy remains the gold standard technique for malaria diagnosis, however, it requires expertise, is time-consuming and difficult to reproduce. Therefore, new diagnostic techniques based on digital image analysis using artificial intelligence tools can improve diagnosis and help automate it.MethodsIn this study, a dataset of 2571 labeled thick blood smear images were created. YOLOv5x, Faster R-CNN, SSD, and RetinaNet object detection neural networks were trained on the same dataset to evaluate their performance in Plasmodium parasite detection. Attention modules were applied and compared with YOLOv5x results. To automate the entire diagnostic process, a prototype of 3D-printed pieces was designed for the robotization of conventional optical microscopy, capable of auto-focusing the sample and tracking the entire slide.ResultsComparative analysis yielded a performance for YOLOv5x on a test set of 92.10% precision, 93.50% recall, 92.79% F-score, and 94.40% mAP0.5 for leukocyte, early and mature Plasmodium trophozoites overall detection. F-score values of each category were 99.0% for leukocytes, 88.6% for early trophozoites and 87.3% for mature trophozoites detection. Attention modules performance show non-significant statistical differences when compared to YOLOv5x original trained model. The predictive models were integrated into a smartphone-computer application for the purpose of image-based diagnostics in the laboratory. The system can perform a fully automated diagnosis by the auto-focus and X-Y movements of the robotized microscope, the CNN models trained for digital image analysis, and the smartphone device. The new prototype would determine whether a Giemsa-stained thick blood smear sample is positive/negative for Plasmodium infection and its parasite levels. The whole system was integrated into the iMAGING smartphone application.ConclusionThe coalescence of the fully-automated system via auto-focus and slide movements and the autonomous detection of Plasmodium parasites in digital images with a smartphone software and AI algorithms confers the prototype the optimal features to join the global effort against malaria, neglected tropical diseases and other infectious diseases.