Insect Parts Research Articles

Comparison of Two Different DNA Isolation Methods (Quick & Dirty vs. Commercial Kit) in Small Insects

The COI gene region is the most commonly employed method for species identification in insects, as in all animals. The importance of DNA isolation methods is increasing, and they are of great importance for identifying insects. Unlike other large animals, DNA isolation from insects, especially from agricultural pests with very small structures, is possible with expensive commercial kits. In this study, an expensive commercial kit and a fast and economical method were compared in terms of time, cost, DNA quantity and quality. It was found that the success of commercial kits in terms of DNA quality and quantity is unquestionable. However, it was determined that the modified ‘quick and dirty’ method can be successfully used to extract DNA from insects and insect parts of all sizes, especially in studies that do not require long-term storage of DNA. Average isolation time for Q&D was 45 minutes, compared to 4 hours or more for commercial kits. Finally, cost is the most important factor in today’s global economy. The unit cost of DNA isolation using the Q&D method is approximately 88% lower.

Feeding habits and diet composition of Schizothorax plagiostomus in Panjkora River, Malakand region, Pakistan

Snow trout (Schizothorax plagiostomus) is a member of the Cyprinidae familyand commonly found in cold waters. We collected fish samples using cast nets and studied seasonal variations in the food consumption of this species. We analysed the gut content of 160 S. plagiostomus. Gut content revealed that S. plagiostomus feeds mainly on plant parts (45.14 %), followed by stones and muds (30.01 %), and insect parts (13.97 %), while unidentified detritus matter (5.42 %) and algae (5.33 %) are in small volume regarding the average percentage on a monthly basis. Maximum food consumption occurred in the summer and minimal food consumption occurred in winter. Seasonal variation in consumption of foods items showed that in summer it feeds mainly on plant parts (0.54 ± 0.86), followed by animal parts (0.19 ± 0.41), and algae (0.06 ± 0.25). In winter it feeds at a relatively minimal level (0.28 ± 0.56), (0.05 ± 0.22), (0.02 ± 0.16), respectively. Detritus (unidentified) was also observed as part of its diet, with a maximum in summer (0.06 ± 0.24), and less in autumn (0.03 ± 0.18). Lastly, materials uch as stones and mud were observed at a maximum level in winter (0.58 ± 0.76) and a minimum level in summer (0.12 ± 0.34). In conclusion, we found that the diet composition of S. plagiostomus changes with season, revealing a diverse diet that includes plants and animal fragments (caddis flies), algae, detritus, stones, and mud.

Composition and Diversity of the Endobacteria and Ectobacteria of the Invasive Bark Beetle Hylurgus ligniperda (Fabricius) (Curculionidae: Scolytinae) in Newly Colonized Areas.

Hylurgus ligniperda (Fabricius) (Curculionidae: Scolytinae) is a new invasive pest beetle in China, which colonized the Shandong province, causing devastating damage. Originating in Europe, it has spread to Oceania, Asia, North and South America. Bacterial associates have been frequently reported to play a vital role in strengthening the ecological adaptations of bark and ambrosia beetles. The environmental adaptability of H. ligniperda may be supported by their associated bacteria. Bacterial communities colonizing different body parts of insects may have different functions. However, little is known about the bacteria associated with H. ligniperda and their potential involvement in facilitating the adaptation and invasion of the beetles into new environments. In this study, we employed high-throughput sequencing technology to analyze the bacterial communities associated with male and female adults of H. ligniperda by comparing those colonizing the elytra, prothorax, and gut. Results showed that the bacterial communities of male and female adults were similar, and the elytra samples had the highest bacterial diversity and richness, followed by the gut, while the prothorax had the lowest. The dominant phyla were Proteobacteria, Firmicutes, and Actinobacteriota, while the dominant genera were Serratia, Lactococcus, Rhodococcus, unclassified Enterobacteriaceae, and Gordonia. Among these, Rhodococcus and Gordonia were the specific genera of endobacteria and ectobacteria, respectively. Differences in the distribution of associated bacteria may suggest that they have different ecological functions for H. ligniperda. The results of functional prediction showed that bacteria were enriched in terpenoid backbone biosynthesis, degradation of aromatic compounds, limonene and pinene degradation, neomycin, kanamycin and gentamicin biosynthesis, indicating that they may assist their beetles in synthesizing pheromones, degrading toxic secondary metabolites of host trees, and antagonizing pathogenic fungi. These results help us understand the interaction between H. ligniperda and bacteria and highlight possible contributions to the invasion process.

Non-invasive characterization of the elastic protein resilin in insects using Raman spectroscopy

Resilin is an extremely efficient elastic protein found in the moving parts of insects. Despite many years of resilin research, we are still only just starting to understand its diversity, native structures, and functions. Understanding differences in resilin structure and diversity could lead to the development of bioinspired elastic polymers, with broad applications in materials science. Here, to better understand resilin structure, we offer a novel methodology for identifying resilin-rich regions of the insect cuticle using non-invasive Raman spectroscopy in a model species, the desert locust (Schistocerca gregaria). The Raman spectrum of the resilin-rich semilunar process of the hind leg was compared with that of nearby low-resilin cuticle, and reference spectra and peaks assigned for these two regions. The main peaks of resilin include two bands associated with tyrosine at 955–962 and 1141–1203 cm−1 and a strong peak at 1615 cm−1, attributed to the α-Amide I group associated with dityrosine. We also found the chitin skeletal modes at ~485–567 cm−1 to be significant contributors to spectra variance between the groups. Raman spectra were also compared to results obtained by fluorescence spectroscopy, as a control technique. Principal component analysis of these resulting spectra revealed differences in the light-scattering properties of resilin-rich and resilin-poor cuticular regions, which may relate to differences in native protein structure and relative abundance.

Butterfly eyespots exhibit unique patterns of open chromatin.

Background: How the precise spatial regulation of genes is correlated with spatial variation in chromatin accessibilities is not yet clear. Previous studies that analysed chromatin from homogenates of whole-body parts of insects found little variation in chromatin accessibility across those parts, but single-cell studies of Drosophila brains showed extensive spatial variation in chromatin accessibility across that organ. In this work we studied the chromatin accessibility of butterfly wing tissue fated to differentiate distinct colors and patterns in pupal wings of Bicyclus anynana. Methods: We dissected small eyespot and adjacent control tissues from 3h pupae and performed ATAC-Seq to identify the chromatin accessibility differences between different sections of the wings. Results: We observed that three dissected wing regions showed unique chromatin accessibilities. Open chromatin regions specific to eyespot color patterns were highly enriched for binding motifs recognized by Suppressor of Hairless (Su(H)), Krüppel (Kr), Buttonhead (Btd) and Nubbin (Nub) transcription factors. Genes in the vicinity of the eyespot-specific open chromatin regions included those involved in wound healing and SMAD signal transduction pathways, previously proposed to be involved in eyespot development. Conclusions: We conclude that eyespot and non-eyespot tissue samples taken from the same wing have distinct patterns of chromatin accessibility, possibly driven by the eyespot-restricted expression of potential pioneer factors, such as Kr.

An Investigation on the Vestiges of Lyroderma lyra and Taphozous melanopogon Guano in Tirunelveli District of Tamil Nadu, India

Chiropterans are the major contributors to mammalian biodiversity. They play a dynamic role in the ecosystem as pollinators, seed dispersers and pest controllers. Among the biocontrol agent of the agro ecosystem, the bats play a major role as a control agent. Their roosting places are mostly near the human habitation and agricultural fields. They forage among the dry deciduous forest and also in the agro ecosystem of the plains. The purpose of this study was to determine the dietary content in the fecal matter of Lyroderma lyra and Taphozous melanopogon in Tirunelveli district, Tamil Nadu. Agriculture is the main resource in this area. The undigested parts in the guano was microscopically observed and identified up to order level. As L. lyra and T. melanopogon are the microbats their Pellet contain large amount of partly digested insect parts. Among them, the order Coleoptera was the most dominant food of L. lyra followed by the other orders whereas for T. melanopogon the most dominantly identified order is lepidopteran followed by the remaining orders. The bats play an important role as pest controller in the ecosystem and hence they need to be protected.

Bags of Stories: Thinking with Household Casebearers in the Anthropocene

Abstract Household casebearers are a genus of moths primarily distinguished by the spindle-shaped cases they carry and live in throughout their larval life. The cases, woven from household dust, typically comprise an array of materials from textile fibers to dead insect parts. As they thrive in domestic spaces in tropical climates, they are commonly viewed as a domestic pest. Anthropocentrism as such has led to a fundamental imbalance of knowledge concerning these creatures: we are more knowledgeable in their capacity for damage than we are in understanding how they live, even as we cohabit with them very closely, at home. In presenting a series of macro photography of their larval cases, this project invites readers to be attentive to the material and ecological entanglements on display on their intricate creations. The home is already a wilderness as household casebearers rebuild their houses from the dusty ruins of ours.

Diet Composition and Dynamics in Fish Species of Ogun Coastal Water, Southwest, Nigeria

Diets composition and dynamics of Eugerres plumieri, Gobioides broussonnetii, Elops aurus, Oreochromis niloticus and Heterotis niloticus in Ogun Coastal water were examined. The fish species were obtained from local fishermen fortnightly between August and October, 2021. The fishes were immediately placed on iced chess after collection and identification before transporting to the laboratory for further examination. All the stomachs of the fishes examined and the contents were analysed using numerical and frequency of occurrence methods. Results indicated that O. niloticus and E. aurus fed on analogous foods which were principally macrophytes, Chlamydomonas species and Spirogyra. Other food items observed in all the fish species includes detritus, sand grains and insect parts. High similarity in the diets dynamics of E. aurus and E. plumieri indicated food competition between the fish species which they both showed high level of trophic flexibility and probably possess same ecological niche.

Diet of Psalidodon aff. fasciatus (Cuvier, 1819) (Teleostei: Characidae) in a neotropical river before reservoir formation

The main objective of this study was to identify spatial and seasonal variations on the diet of Psalidodon aff. fasciatus from the Tibagi River (South Brazil) before the construction of the Tibagi Montante hydropower plant. Fish were collected quarterly between October 2017 and July 2019. 536 stomachs containing feeding items and identified to the lowest taxonomic level as possible have been analyzed. Results showed that plants, Hymenoptera, and insect parts in general were the most consumed items. The analysis of feeding strategy showed a diet based on rare items but with individuals varying among specialist, generalist, and opportunistic trends depending on the season. The non-metric multidimensional scaling (NMDS) revealed diet overlap in both spatial and seasonal terms, which was confirmed by the permutational analysis of variance (PERMANOVA). The indicator value analysis (IndVal) identified 15 items as the most important components of this species’ diet such as superior plants, Hymenoptera and insect parts. Therefore, before the formation of the reservoir, P. aff. fasiatus could be characterized as predominantly herbivore with a strong trend for insectivory. Across seasons, this species had a specialized diet all year, although with more specialized preferences in the spring when the consumption of plants was increased.

Establishing Modern Peat Analogs to Decipher Mangal Sub-Habitats From Historical Peats

In mangroves of South Florida, plant debris accumulates and humifies to form peat. The structure and composition of mangrove peat differs among mangal sub-habitats, leading to categorically distinct peat types reflective of the taphonomically active zone (TAZ). Here, taphonomic processes degrade and shape the peat until it is sequestered in the depth of final burial (DFB). Sequestered peats provide historical archives of the mangal depositional environment and the palaeoecological context of peat formation that are used to reconstruct mangal sub-habitats. However, as peat passes through the TAZ, information about the precursor mangal sub-habitat is reduced, which may skew mangrove community reconstructions. To better understand the influence of the TAZ on peat formation, we analyzed plant organ- and taxon-based measures by characterizing surficial mangrove peats from two contrasting mangal sub-habitats in Barnes Sound, Florida: a tidally influenced, Rhizophora-dominated fringe sub-habitat; and an inundated, interior mixed forest basin sub-habitat. We found (1) peats formed in basin sites have greater amounts of leaf litter, which correlates with reduced tidal activity and restricted detritivore access to the litter layer; (2) peats formed in fringe sites have higher root percentages, or root–shoot ratios, which provide a reliable method to differentiate between peats at depth, and (3) mangal sub-habitats differ in preserved organismal signals, such as foraminifera and insect parts. Further, we compare our surficial core samples to historical, deep core samples from other South Florida mangrove peat deposits to establish modern peat analogs needed to decipher preserved mangrove peats. These comparisons suggest that few aerial plant organs survive the TAZ and sequestered peats are biased towards root-rich peats characteristic of fringe sub-habitats; however, sequestered peats with lower root-shoot ratios indicate leaf litter-rich peats formed in basin sub-habitats.

The influence of the taphonomically active zone on peat formation: Establishing modern peat analogs to decipher mangrove sub-habitats from historical peats

Mangroves create unique and highly productive wetland communities in intertidal zones of tropical and subtropical coastlines. Despite their many ecosystem services, such as carbon sequestration, mangroves remain threatened by climate change, sea-level rise, and human development. The inclusion of conservation paleobiology and long-term perspectives on how these ecosystems have responded to past environmental change can inform current policy and lead to more effective conservation and restoration management strategies for modern mangrove communities. In South Florida, humified plant debris, or peat, in mangroves provides this historical record. Our research takes a novel paleobiological approach by using plant organ- and taxon-based measures to describe the influence of the taphonomically active zone (TAZ: the zone near the surface of the substrate where taphonomic processes actively formation and degrade accumulated detritus) on the decomposition of mangrove peat with depth. This allows us to understand the taphonomic biases imposed on mangrove peat as it is sequestered into the sedimentological record and provides us with the paleoecological context to better interpret preserved peats and reconstruct past mangrove sub-habitats from peat cores. Accordingly, we collected modern surficial peat cores from two contrasting mangrove sub-habitats in Barnes Sound, FL. These surficial cores were characterized and compared to historical, deep cores from other South Florida mangrove peat deposits. By comparing the proportional abundance of mangrove peat constituents in these samples, we established modern analogs needed to interpret changes in the depositional environment of historical mangrove peats found in sediment cores, which is critical for understanding shoreline responses of mangroves to sea-level rise and anthropogenic change. We demonstrate that (1) leaf mat thickness may be a relative indicator of surficial peat decomposition rates because it correlates with the degree of tidal activity and detritivore access to the leaf litter layer; (2) root percentages are valid tools to differentiate between peats at depth, and can be used as relative indicators for the distance of in situ peat from shorelines; and (3) organismal signals, such as foraminifera and insect parts, provide a means for deciphering precursor mangrove sub-habitats from sequestered peats.

A Polyimide Film-Based Simple Force Plate for Measuring the Body Mass of Tiny Insects

Insects exhibit excellent maneuvers such as running and flying despite their small bodies; therefore, their locomotion mechanism is expected to provide a design guideline for micromachines. Numerical simulations have been performed to elucidate this mechanism, whereby it is important to develop a model that is physically identical to the target insect's parts to reproduce kinematic dynamics. In particular, in flight, the shape and mass of wings, which flap at high frequencies, are significant parameters. However, small insects such as fruit flies have small, thin, and light wings; thus, their mass cannot be easily measured. In this study, we proposed a high-resolution and simple force plate to measure the mass of each part of a tiny insect. The device consists of a circular plate supported by flat spiral springs made of polyimide film, and a laser displacement meter that detects the displacement of the center of the plate. The simple plate fabrication process requires only a couple of minutes. A fabricated force plate with a sub-N/m spring constant achieved a resolution of less than 2 µg. As a demonstration, the wing mass of the fruit flies was measured. The experimental results suggest that the wings accounted for approximately 0.4% of the body mass.

Identification and characterization of a recombinant cysteine peptidase (AsCathL) from leaf-cutting ant Atta sexdens Linnaeus, 1758 (Hymenoptera, Formicidae)

Cysteine peptidases are involved in physiological processes of insect development and have been considered as potential targets for the development of insect control strategies. In this study, we obtained a recombinant cysteine cathepsin L (AsCathL) from leaf-cutting ant (Atta sexdens), a species from the order Hymenoptera who causes enormous damage to crops, natural forests and reforested areas. RT-qPCR showed AsCathL expression throughout insect development and in all body parts of the adult insect analysed, suggesting its role as a lysosomal cathepsin. AsCathL encodes a protein of 320 amino acid residues consisting of a pro-peptide and the mature with amino acids sequence over 67% similarity with lysosomal cathepsin L of species from Lepidoptera and Diptera. Phylogenetic tree revealed that AsCathL is very similar to predicted cathepsins found in other ants. Recombinant AsCathL was expressed in insoluble form by Escherichia coli Arctic Express (DE3) RIL, purified under denaturing conditions and refolded. The enzyme showed hydrolytic activity in vitro towards synthetic substrate Z-Phe-Arg-AMC at acidic pH. Synthetic inhibitor E−64 acted against peptidase activity and a study regarding the interaction between E−64 and AsCathL using nuclear magnetic resonance (NMR) revealed that 83.18% from all E−64 molecules are irreversibly bound to AsCathL. In addition, the proteolytic activity of AsCathL was strongly inhibited by recombinant sugarcane cystatins with Ki ranging from 0.6 nM to 2.95 nM. To the best of our knowledge this is the first report characterizing a cysteine peptidase from leaf-cutting ants, which may contribute to future studies of ants’ cathepsins.

Let's make a mess, maybe no one will notice. The impact of bioturbation activity on the urn fill condition.

The research was carried out at the cremation cemetery of the Lusatian culture in Wtórek, Ostrów Wielkopolski district, Wielkopolska province, Poland. Contrary to the so-far-studied topics related to the CT imaging of burnt bones and their virtual exploration, we concentrated on the analysis of the structures formed by the soil fauna activity in the fills of urns and additional vessels, and reconstruction of the dynamics of the ecosystem variability within the cemetery area based on thereof. We also demonstrated the impact of macrofaunal activity on stratigraphy and bone fragmentation. From the total of 222 excavated burials in 18 urns and one additional vessel, the remains of macrofauna or its bioturbation activity were identified. Out of 19 vessels subjected to CT examinations, traces of macrofaunal activity were demonstrated in 13: in five vessels animal bioturbative activity was not observed and in one, observations was impossible (due to significant metal-related artifacts). In two vessels both macrofaunal remains and traces of activity were identified. Discovered bioturbations were associated with specific species or genera. Nests or their parts of the genus Geotrupes sp. beetles were the most frequently observed traces of macrofaunal activity. Tunnels and aestivation chambers of earthworms and chambers of the genus Harpalus sp. beetles filled with Setaria sp. caryopses were discovered. The chitinous parts of other insects and the humerus bones of the vole of the genus Microtus sp. were also identified. It was shown, especially due to the non-destructive method, that rodents activity had the most destructive effect on the bone stratigraphy as well as on the movement and fragmentation of the burnt bones. The chances of visualizing bioturbations decreased with time since their creation. The process of disappearance of traces of macrofaunal activity concerned both traces of rodent activity and nests set up by Geotrupes sp. and other species.

Ceratocystiopsis quercina sp. nov. Associated with Platypus cylindrus on Declining Quercus suber in Portugal.

Simple SummaryThe presence of the oak pinhole borer, the insect Platypus cylindrus, in Portuguese cork oak stands has drastically increased in the past few decades. This beetle excavates long galleries in the trunk while inoculating fungi (called ambrosia fungi) transported in special organs (mycangia) that will serve as food source for its offspring. The combined action of extensive boring into the heartwood and the inoculation of fungi leads to an increase in tree mortality. A new ambrosial fungus, Ceratocystiopsis quercina, was isolated from the insects’ mycangia and from wilting trees, namely from the staining patches it causes on wood.Platypus cylindrus is the most common ambrosia beetle in stands of Quercus suber in Portugal. This insect farms specialized fungi in sapwood galleries, using its mycangia to carry and store these organisms. Some ectosymbiotic fungi carried by P. cylindrus are phytopathogenic and cause extensive tree mortality and severe economic losses. To understand the role of P. cylindrus fungal symbionts in stands of Q. suber we examined beetle galleries present in declining and/or dying cork oak trees during field surveys. Logs with active galleries were obtained in situ and from captured emerging beetles. Insects were aseptically dissected, and their mycangia and intestine were retrieved. Morphological and molecular profiles of fungal isolates obtained from cultured insect parts were carried out to accurately characterize and identify isolated fungi. Molecular characterizations were performed with DNA sequence data from four loci, i.e., LSU, SSU, 5.8S-ITS2-28S, and TUB. Morphological results consistently showed a collection of Ophiostoma-like fungal axenic isolates, while phylogenies inferred that this collection constitutes an undescribed taxon reported herein for the first time in association with P. cylindrus in Portuguese cork oak stands. The novel species was erected as Ceratocystiopsis quercina sp. nov. and constitutes a new phytopathogenic fungal species associated with symptoms of vegetative cork oak decline.

Leveraging machine learning tools and algorithms for analysis of fruit fly morphometrics

Analysis of landmark-based morphometric measurements taken on body parts of insects have been a useful taxonomic approach alongside DNA barcoding in insect identification. Statistical analysis of morphometrics have largely been dominated by traditional methods and approaches such as principal component analysis (PCA), canonical variate analysis (CVA) and discriminant analysis (DA). However, advancement in computing power creates a paradigm shift to apply modern tools such as machine learning. Herein, we assess the predictive performance of four machine learning classifiers; K-nearest neighbor (KNN), random forest (RF), support vector machine (the linear, polynomial and radial kernel SVMs) and artificial neural network (ANNs) on fruit fly morphometrics that were previously analysed using PCA and CVA. KNN and RF performed poorly with overall model accuracy lower than “no-information rate” (NIR) (p value > 0.1). The SVM models had a predictive accuracy of > 95%, significantly higher than NIR (p < 0.001), Kappa > 0.78 and area under curve (AUC) of the receiver operating characteristics was > 0.91; while ANN model had a predictive accuracy of 96%, significantly higher than NIR, Kappa of 0.83 and AUC was 0.98. Wing veins 2, 3, 8, 10, 14 and tibia length were of higher importance than other variables based on both SVM and ANN models. We conclude that SVM and ANN models could be used to discriminate fruit fly species based on wing vein and tibia length measurements or any other morphologically similar pest taxa. These algorithms could be used as candidates for developing an integrated and smart application software for insect discrimination and identification. Variable importance analysis results in this study would be useful for future studies for deciding what must be measured.

Investigation of Leifsonia xyli subsp. xyli in insects

Leifsonia xyli subsp. xyli, the causal agent of ratoon stunting, is an endophytic bacteria that colonize sugarcane xylem vessels. It is generally accepted that sugarcane is the only natural host of ratoon stunting. The objective of this work was to investigate the presence of bacteria in insects associated with sugarcane in an experimental area cultivated with four varieties. The plants were artificially inoculated with bacteria, the samples of insects were collected from the sugarcane crop. Specific PCR was used with DNA extracted from different insect parts (head, abdomen, or whole-body). The DNA of the bacterium was not detected in those investigated insects, confirming that the host range of the bacterium is restricted to Saccharum spp.

Application of insects to wounds of self and others by chimpanzees in the wild

Self-medication refers to the process by which a host suppresses or prevents the deleterious effects of parasitism and other causes of illness via behavioural means1. It has been observed across multiple animal taxa (e.g. bears, elephants, moths, starlings)2, with many case studies in great apes1,3. Although the majority of studies on self-medication in non-human primates concern the ingestion of plant parts or non-nutritional substances to combat or control intestinal parasites4, more recent examples also report topical applications of leaves or other materials (including arthropods) to skin integuments3. Thus far, however, the application of insects or insect parts to an individual's own wound or the wound of a conspecific has never been reported. Here, we report the first observations of chimpanzees applying insects to their own wounds (n = 19) and to the wounds of conspecifics (n = 3).

Fungal Spore Diversity over Garbage Depot of Pimpri Chinchwad, Pune, M.S., India

Aerobiology deals with the airborne particles of biological origin and their effect on living organisms. The atmosphere of the big city including Pimpri Chinchwad is dominated by biopollutants such as grain pollen, fungal grains and piles of dust particles. These days garbage disposal is a major problem in various cities. Many nearby villages are experiencing serious health problems due to elevated levels of aerobiopollutants. Air monitoring within garbage depot has been very rare. Therefore, it was felt that if a continuous survey of aerobiocomponents is conducted, it may be helpful in solving or suggesting a suitable solution. The present study deals with the assessment of aeromicrobiota over the garbage depot of Moshi, Pune for a year (Jan 2019 to Dec 2019). The study aimed to monitor the concentration of various biocomponents in the atmosphere over garbage depot. While scanning the prepared slides of the garbage depot for a year, fungal spores, pollen, hyphal fragments, insect parts, etc. were observed. However, during the present investigation, more emphasis has been given to the fungal components of airspora. The outcome of the present study would ultimately help allergy clinicians in the treatment of allergies and to the Municipal Corporation for designing the dumping site for garbage and developing better garbage disposal mechanisms ultimately bringing comfort to the population of the adjoining area.

Quantifying Farmers’ Exposure to Corn and Soybean Dust in On-Farm Grain Storage Bins

HighlightsOn-farm samples were used to analyze farmers’ exposure to dust while cleaning and unloading their grain bins.Over 18% of samples exceeded the 8-hour time-weighted average (TWA) concentration recommended by ACGIH for respirable dust, and over 27% of samples exceeded the ACGIH recommendation for total suspended particles.The results strengthen the need for relevant agricultural safety education programs to help farm workers understand the health hazards associated with grain dust.Abstract. Grain dust consists of grain particles, insect parts, silica, bacteria, fungi, and mycotoxins. The size of these airborne particulates is a concern because they can become deeply lodged in the respiratory tract. Exposure to grain dust can diminish overall lung function and lead to respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD), organic dust toxic syndrome (ODTS), chronic bronchitis, and hypersensitivity pneumonitis (farmer’s lung). Grain storage and handling facilities are primary work locations with high levels of grain dust concentrations. The objective of this study was to understand farmers’ exposure to grain dust while cleaning and unloading their grain bins. During on-farm dust sampling, researchers visited farms to collect dust samples for analysis. Two types of samples were taken. Integrated samples provided average concentrations of total dust and respirable dust while farmers performed their normal tasks in the grain bin. Real-time samples provided instantaneous concentrations of respirable dust (RESP) and total suspended particles (TSP) and how the variations changed during the farmers’ working periods. From the data collected in corn storage bins, RESP concentrations ranged from 4.1 to 6.6 mg m-3, and TSP concentrations ranged from 33 to 70.7 mg m-3. From the data collected in soybean storage bins, RESP concentrations ranged from 1.6 to 82.3 mg m-3, and TSP concentrations ranged from 8.9 to 146.8 mg m-3. Based on the calculated 8-hour time-weighted average (TWA) concentration of all samples, 18.2% of the 8-hour TWA RESP concentrations exceeded the ACGIH-recommended respirable dust concentration of 3 mg m-3, and 27.3% of the 8-hour TWA TSP concentrations exceeded the ACGIH-recommended total dust concentration of 610 mg m-3. The results strengthen the need for relevant agricultural safety education programs to help farm workers understand the health hazards associated with grain dust. Keywords: Grain dust concentrations, Occupational health, On-farm grain storage bins.