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1.
iScience ; 27(4): 109410, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38558941

RESUMO

The tobacco hornworm is a laboratory model that is particularly suitable for analyzing gut inflammation, but a physiological reference standard is currently unavailable. Here, we present a surface atlas of the healthy hornworm gut generated by scanning electron microscopy and nano-computed tomography. This comprehensive overview of the gut surface reveals morphological differences between the anterior, middle, and posterior midgut, allowing the screening of aberrant gut phenotypes while accommodating normal physiological variations. We estimated a total resorptive midgut surface of 0.42 m2 for L5d6 larvae, revealing its remarkable size. Our data will support allometric scaling and dose conversion from Manduca sexta to mammals in preclinical research, embracing the 3R principles. We also observed non-uniform gut colonization by enterococci, characterized by dense biofilms in the pyloric cone and downstream of the pylorus associated with pore and spine structures in the hindgut intima, indicating a putative immunosurveillance function in the lepidopteran hindgut.

2.
Int J Legal Med ; 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38589642

RESUMO

Blow flies (Diptera: Calliphoridae) are generally early colonisers of fresh cadavers, enabling the estimation of a minimum post-mortem interval (minPMI) based on an accurate aging of the oldest immature stages associated with a cadaver. In blow flies, the pupal stage and the subsequent development of the adult take place inside a protective case, the puparium, formed from the hardened and darkened cuticle of the third instar larva. Because the puparium is an opaque structure that shows virtually no external changes, qualitative analyses of the internal tissues can be very informative for determining reliable age-specific morphological markers. Those analyses can be performed using either non-invasive but expensive and not widely accessible techniques, or traditional histological methods, which are invasive as they require the serial sectioning of the sample. Histological methods are often readily available for forensic researchers and practitioners; however, the histological study of blow fly intra-puparial stages has traditionally been hampered by the poor paraffin infiltration of tissues due to the abundance of fat bodies, resulting in usually fragmented sections and the subsequent loss of relevant information. We present here an effective method for the preparation of histological sections of blow fly intra-puparial stages, maximising the paraffin infiltration while enabling the production of clean and entire sections that allow for the use of reliable age-specific morphological markers, thus improving the accuracy of minPMI estimations when access to more costly techniques is not feasible.

3.
iScience ; 27(4): 109541, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38577108

RESUMO

As ectotherms, insects need heat-sensitive receptors to monitor environmental temperatures and facilitate thermoregulation. We show that TRPA5, a class of ankyrin transient receptor potential (TRP) channels absent in dipteran genomes, may function as insect heat receptors. In the triatomine bug Rhodnius prolixus (order: Hemiptera), a vector of Chagas disease, the channel RpTRPA5B displays a uniquely high thermosensitivity, with biophysical determinants including a large channel activation enthalpy change (72 kcal/mol), a high temperature coefficient (Q10 = 25), and in vitro temperature-induced currents from 53°C to 68°C (T0.5 = 58.6°C), similar to noxious TRPV receptors in mammals. Monomeric and tetrameric ion channel structure predictions show reliable parallels with fruit fly dTRPA1, with structural uniqueness in ankyrin repeat domains, the channel selectivity filter, and potential TRP functional modulator regions. Overall, the finding of a member of TRPA5 as a temperature-activated receptor illustrates the diversity of insect molecular heat detectors.

4.
iScience ; 27(5): 109588, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38646171

RESUMO

The seasonal migrations of insects involve a substantial displacement of biomass with significant ecological and economic consequences for regions of departure and arrival. Remote sensors have played a pivotal role in revealing the magnitude and general direction of bioflows above 150 m. Nevertheless, the takeoff and descent activity of insects below this height is poorly understood. Our lidar observations elucidate the low-height dusk movements and detailed information of insects in southern Sweden from May to July, during the yearly northward migration period. Importantly, by filtering out moths from other insects based on optical information and wingbeat frequency, we have introduced a promising new method to monitor the flight activities of nocturnal moths near the ground, many of which participate in migration through the area. Lidar thus holds the potential to enhance the scientific understanding of insect migratory behavior and improve pest control strategies.

5.
Int J Legal Med ; 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38622312

RESUMO

The decomposition of animal remains is a multifaceted process, involving ecological, biological, and chemical interactions. While the complexity is acknowledged through concepts like the necrobiome, it's unclear if this complexity is reflected in research. Appreciation of the complexity of decomposition is crucial for identifying sources of variation in estimations of time since death in medico-legal science, as well as building broader ecological knowledge of the decomposition process. To gain insights into the extent of multidisciplinary research in the field of decomposition science, we conducted an examination of peer-reviewed literature on four key drivers of variation: volatile organic compounds, microbes, drugs/toxins, and insects. Among 650 articles, we identified their scientific discipline, driver/s of variation investigated, and year of publication. We found that 19% explored relationships between two drivers, while only 4% investigated interactions between three. None considered all four drivers. Over the past three decades, there has been a steady increase in decomposition research publications, signifying its growing importance. Most research (79%) was linked to forensic science, highlighting opportunities for interdisciplinary collaboration in decomposition science. Overall, our review underscores the need to incorporate multidisciplinary approaches and theory into contemporary decomposition research.

6.
Adv Sci (Weinh) ; : e2400844, 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38613834

RESUMO

Scaling in insect wings is a complex phenomenon that seems pivotal in maintaining wing functionality. In this study, the relationship between wing size and the size, location, and shape of wing cells in dragonflies and damselflies (Odonata) is investigated, aiming to address the question of how these factors are interconnected. To this end, WingGram, the recently developed computer-vision-based software, is used to extract the geometric features of wing cells of 389 dragonflies and damselfly wings from 197 species and 16 families. It has been found that the cell length of the wings does not depend on the wing size. Despite the wide variation in wing length (8.42 to 56.5 mm) and cell length (0.1 to 8.5 mm), over 80% of the cells had a length ranging from 0.5 to 1.5 mm, which was previously identified as the critical crack length of the membrane of locust wings. An isometric scaling of cells is also observed with maximum size in each wing, which increased as the size increased. Smaller cells tended to be more circular than larger cells. The results have implications for bio-mimetics, inspiring new materials and designs for artificial wings with potential applications in aerospace engineering and robotics.

7.
Neotrop Entomol ; 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38656589

RESUMO

Currently, according to the most recent Simuliidae World Inventory, there are 97 valid species of blackflies recorded in Brazil, some of which act as vectors for zoonoses such as human onchocerciasis and mansonellosis in the northern and central-western regions of the country. Meanwhile, other species can cause serious socioeconomic problems due to the nuisance of female bites. Therefore, accurate knowledge of their distribution is crucial for the development and implementation of successful preventive strategies. With this aim, this study reviewed and updated the geographical distribution of the blackfly fauna throughout the Brazilian states. The data were compiled from three main sources: geographic information of material deposited at the Simuliidae Collection of the Instituto Oswaldo Cruz (CSIOC-IOC), a comprehensive review of scientific literature, and online biodiversity databases. We present a total of 71 new distribution records of 38 different Simuliidae species for 24 Brazilian states. Neither of these sets of records has been included in the Simuliidae World Inventory. Consequently, an updated Brazilian Simuliidae checklist, comprising a total of 98 valid species, is presented, highlighting these new distribution records. We also discuss six dubious records for the country and the implications of this updated data for the Simuliidae species richness of Brazil, its states, and biomes. This information is essential for future studies in the taxonomy, systematics, and biogeography of this family in Brazil.

8.
Proc Natl Acad Sci U S A ; 121(18): e2317646121, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38648486

RESUMO

Long-distance migrations of insects contribute to ecosystem functioning but also have important economic impacts when the migrants are pests or provide ecosystem services. We combined radar monitoring, aerial sampling, and searchlight trapping, to quantify the annual pattern of nocturnal insect migration above the densely populated agricultural lands of East China. A total of ~9.3 trillion nocturnal insect migrants (15,000 t of biomass), predominantly Lepidoptera, Hemiptera, and Diptera, including many crop pests and disease vectors, fly at heights up to 1 km above this 600 km-wide region every year. Larger migrants (>10 mg) exhibited seasonal reversal of movement directions, comprising northward expansion during spring and summer, followed by southward movements during fall. This north-south transfer was not balanced, however, with southward movement in fall 0.66× that of northward movement in spring and summer. Spring and summer migrations were strongest when the wind had a northward component, while in fall, stronger movements occurred on winds that allowed movement with a southward component; heading directions of larger insects were generally close to the track direction. These findings indicate adaptations leading to movement in seasonally favorable directions. We compare our results from China with similar studies in Europe and North America and conclude that ecological patterns and behavioral adaptations are similar across the Northern Hemisphere. The predominance of pests among these nocturnal migrants has severe implications for food security and grower prosperity throughout this heavily populated region, and knowledge of their migrations is potentially valuable for forecasting pest impacts and planning timely management actions.

9.
J Econ Entomol ; 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38518379

RESUMO

This study determined a cost-effective larval diet for rearing Calliphora dubia Macquart for use as a potential managed pollinator in Australia. This fly has potential as a pollination species to support honey bees (Apis mellifera). Larvae of C. dubia were reared mostly in meat meals with varying amounts of either whole egg powder, whole eggs (+ shell), bran flakes, skimmed milk powder, brewer's yeast, or poultry oil. This was done from an economic and production perspective to support commercial rearing. Several laboratory-based studies determined the growth and output from various ingredient combinations. Larvae fed 90% meat meal and 10% whole egg powder developed rapidly through to pupation with a high pupation rate, adult size, and percent adult emergence. Given the high cost and difficulty in sourcing whole egg powder, media comprising mostly meat meals with the addition of bran flakes and whole eggs also supported rapid larval development, pupation rate, and adult emergence. The ideal amount of media/larvae was 0.5 g/larvae to support high pupation rates and adult emergence. Adult eclosion occurred over 4-5 days, even when larvae were laid and fed within 1 h on ample media. Commercial mass rearing would then require daily cohorts of larvae to ensure peak adult fly emergence over 1-2 days for release into a crop. Mass-rearing C. dubia should use meat meal as the base ingredient with bran flakes and whole eggs added and fed at 0.5 g of media/larvae. Based on the current media ingredient costs, rearing 1-m adult C. dubia would cost just over $500 (US$342).

10.
Gac Sanit ; 2024 Mar 06.
Artigo em Espanhol | MEDLINE | ID: mdl-38519323

RESUMO

The first detection of the tiger mosquito, Aedes (Stegomyia) albopictus (Skuse, 1894), in the autonomous community of Galicia (Spain) is reported. The finding has been possible thanks to the collaboration between citizens, the citizen science application Mosquito Alert and the Rede Galega de Vixilancia de Vectores (ReGaViVec). At the beginning of August 2023, a same person submitted through the app several reports consistent with the tiger mosquito in the municipality of Moaña, in Pontevedra. The ReGaViVec entomological team confirmed the species and conducted vector surveillance in the area by placing traps (11 ovitraps and 3 BG-Sentinel 2 with BG-Lure attractant) with a weekly collection frequency. This finding represents the most northwestern detection of the tiger mosquito in the Iberian Peninsula and shows the crucial role of citizen science in vector surveillance.

11.
iScience ; 27(4): 109336, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38500827

RESUMO

Temperature is thought to be a key factor influencing global species richness patterns. We investigate the link between temperature and diversification in the butterfly family Pieridae by combining next generation DNA sequences and published molecular data with fine-grained distribution data. We sampled nearly 600 pierid butterfly species to infer the most comprehensive molecular phylogeny of the family and curated a distribution dataset of more than 800,000 occurrences. We found strong evidence that species in environments with more stable daily temperatures or cooler maximum temperatures in the warm seasons have higher speciation rates. Furthermore, speciation and extinction rates decreased in tandem with global temperatures through geological time, resulting in a constant net diversification.

12.
Ann Entomol Soc Am ; 117(2): 92-106, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38486925

RESUMO

Pollinators are critical for agricultural production and food security, leading to many ongoing surveys of pollinators (especially bees) in crop and adjacent landscapes. These surveys have become increasingly important to better understand the community of potential pollinators, quantify relative insect abundance, and secure crop ecosystem services. However, as some bee populations are declining, there is a need to align and improve bee survey efforts, so that they can best meet research and conservation goals, particularly in light of the logistical and financial constraints of conducting such studies. Here, we mined the existing literature on bee surveys in or around agricultural lands to better understand how sampling methods can be optimized to maximize estimates of 2 key measures of bee communities (abundance and richness). After reviewing 72 papers spanning 20 yr of publication, we found that study duration, number of sites, sampling time, and sampling method most significantly influenced abundance, while the number of trips per year and collection method significantly influenced richness. Our analysis helps to derive thresholds, priorities, and recommendations that can be applied to future studies describing bee communities in agroecosystems.

13.
Forensic Sci Int ; 357: 111972, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38430653

RESUMO

The cosmopolitan blow fly Lucilia sericata is often used in forensic case work for estimating the minimum postmortem interval (PMImin). For this, the age of immature specimens developing on the dead body is calculated by measuring the time taken to reach the sampled developmental stage at a given temperature. To test whether regional developmental data of L. sericata is valid on a global scale, the time taken to reach different developmental stages was compared between a population from Mexico and one from Germany at two different constant temperatures. The German population of L. sericata was collected in Frankfurt/Main, while the Mexican population originated near Oaxaca de Juarez and was transported to Germany in the larval stage. Only the F1 generation was used to avoid adaption of the Mexican flies. Eggs were immediately placed at 20 °C and 30 °C. Five times 30 freshly eclosed larvae per replicate (n = 5) were then transferred to a cup of minced meat in separate containers. The larvae were checked every 8 h for migration, pupariation or emergence of adult flies. The time at which the first individual and 50 % of the specimens per container entered each of these stages, was recorded. Significant differences in the time of development between the two populations were observed at both temperatures. At 20 °C, the first specimens of the Mexican population reached all developmental stages a little (< 1 day to < 2 days) earlier than the German L. sericata. At 30 °C, the Mexican flies also reached the post-feeding stage slightly earlier (0.2 days). However, at 30 °C, the German flies started pupariation significantly earlier (after 5 days) than the Mexican flies (6.9 days) and the adults from Germany also emerged earlier (10.5 days compared to 13.1 days). The same pattern was observed when looking at 50 % of the total number of specimens per container. A comparison with previously published developmental studies was difficult as the experimental design varied widely between studies. However, the results were within the range of most studies. Our study has shown that age estimation can vary widely depending on the population on which the reference data used for the calculations are based. This highlights the importance of using local and population-specific developmental data for estimating the age of blow flies in case work.


Assuntos
Calliphoridae , Dípteros , Animais , Entomologia , Larva , Temperatura
14.
Acta Trop ; 253: 107164, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38431136

RESUMO

The anthropization process exerts a profound effect on ecosystems, causing alterations in biodiversity, habitat structure, and species composition, ultimately disrupting the delicate balance of natural environments. The aim of the present study was to explore the ecological dynamics of necrophagous Sarcophagidae and Calliphoridae flies along an anthropization gradient. This research investigated alpha and beta diversity patterns to unravel the impact of human-induced environmental changes on these insect communities and also assesses the dynamics of functional groups in relation to their impact on medical and forensic fields. Five distinct habitats, ranging from urban to forested areas, were surveyed in two Departments in the Province of Chaco, Argentina. Necrophagous flies were collected using van Someren-Rydon canopy traps across three seasons. Two main functional groups were analyzed: oviparous flies (Calliphoridae) and larviparous flies (Sarcophagidae). Results indicated a significant negative correlation between Sarcophagidae species richness and anthropization, whereas Calliphoridae showed increased abundance in highly anthropized sites. The combined assemblage of Calliphoridae+Sarcophagidae exhibited significant relationships across all community parameters evaluated. Beta diversity analysis revealed turnover as the main process shaping dipteran communities along the anthropization gradient, with spatial species replacement dominating. This underscores the importance of interspecific spatial segregation in dipteran community composition. In conclusion, this study enhances our understanding of the ecological adaptations of necrophagous dipterans to anthropogenic disturbances. The observed shifts in diversity and abundance have implications for forensic investigations and public health, emphasizing the need for nuanced monitoring and conservation strategies. This research contributes valuable insights into the intricate ecological interactions of these insect communities within changing ecosystems.


Assuntos
Dípteros , Sarcofagídeos , Humanos , Animais , Ecossistema , Dípteros/fisiologia , Sarcofagídeos/fisiologia , Calliphoridae , Insetos , Biodiversidade
15.
J Forensic Sci ; 69(3): 944-952, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38491762

RESUMO

A carcass is defined as a temporary resource that can support high levels of diversity compared to other resources. The level of diversity often depends on the environmental conditions in which the corpse is found. Calliphoridae (Diptera) are the most important necrophagous insects used in forensic investigations because this family is common, widespread, abundant, and usually the first to colonize a corpse. However, understanding the processes responsible for variation in calliphorid species abundance and richness along gradients in ecology remains a key challenge. In this study, we analyzed the influence of altitude on the abundance and diversity of Calliphoridae species in corpses at three different altitudes (400, 900, and 1500 m a.s.l.) in a mountainous area of southeastern Spain. The results revealed a gradient of decreasing abundance with increasing altitude. An altitudinal substitution of species was observed, with Chrysomya albiceps being found at the lowest altitude and Calliphora vicina at the highest altitude. Seasonal variation was also noted, with Ch. albiceps being the dominant species in the warmer months and C. vicina being the dominant species in winter. Our results confirm the importance of Calliphorids as seasonal, altitudinal, and environmental indicators, given the wide distribution and abundance of this family. This information is of great interest on the interpretation of data in forensic practice.


Assuntos
Altitude , Calliphoridae , Comportamento Alimentar , Entomologia Forense , Estações do Ano , Animais , Espanha , Calliphoridae/crescimento & desenvolvimento , Humanos , Mudanças Depois da Morte , Dípteros
16.
iScience ; 27(4): 109441, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38523795

RESUMO

Insect physiology and reproduction depend on several terpenoid compounds, whose biosynthesis is mainly unknown. One enigmatic group of insect monoterpenoids are mealybug sex pheromones, presumably resulting from the irregular coupling activity of unidentified isoprenyl diphosphate synthases (IDSs). Here, we performed a comprehensive search for IDS coding sequences of the pest mealybug Planococcus citri. We queried the available genomic and newly generated short- and long-read P. citri transcriptomic data and identified 18 putative IDS genes, whose phylogenetic analysis indicates several gene family expansion events. In vitro testing confirmed regular short-chain coupling activity with five gene products. With the candidate with highest IDS activity, we also detected low amounts of irregular coupling products, and determined amino acid residues important for chain-length preference and irregular coupling activity. This work therefore provides an important foundation for deciphering terpenoid biosynthesis in mealybugs, including the sex pheromone biosynthesis in P. citri.

17.
Forensic Sci Res ; 9(1): owad049, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38545404

RESUMO

Postmortem interval may be estimated based on the age of insect evidence collected on a death scene. Reference data that are used in such estimation frequently comprise thermal summation constant (i.e. k), which is equal to the insect age upon completion of immature development expressed in accumulated degree-days or degree-hours (ADD or ADH). Essentially, k is a central point of an insect group and it may poorly represent insect evidence that is near the limits of variation for the group. Accordingly, it was postulated to calibrate k for particular insect evidence and insect size and sex were found to be useful for this purpose in some of the species. However, the calibration is only possible by using the model that correlates k with insect size. Since very few such models were published, this lack of data limits the calibration of k in forensic casework. In this article, we develop a formula that is useful for the calibration of k without the use of "k versus size" model (and related datasets). The formula uses k from the general thermal summation model for a species (with its standard error), size range for the species (retrieved from entomology literature), and size measurements for particular insect evidence. The calibration of k with the formula was validated using the Creophilus maxillosus (Coleoptera: Staphylinidae) and Necrodes littoralis (Coleoptera: Silphidae) datasets. It was particularly useful while analyzing unusually small and large insects, in case of which the formula reduced the inaccuracy of k from the general model on average by ~25 ADD in C. maxillosus and ~40 ADD in N. littoralis. We discuss the limitations and prospects of the calibration protocol that employs the formula.

18.
ACS Biomater Sci Eng ; 10(4): 2088-2099, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38427786

RESUMO

Silk fibers are produced by a wide variety of insects. The silkworm Bombyx mori (Bombyx) was domesticated because the physical properties of its silk fibers were amenable to the production of fine textiles. Subsequently, engineers have regenerated silk fibroin to form biomaterials. The monocular focus on Bombyx silk has underutilized the expanse of diverse silk proteins produced by more than 100,000 other arthropods. This vast array of silk fibers could be utilized for biomedical engineering challenges if sufficient rearing and purification processes are developed. Herein, we show that the moth, Plodia interpunctella (Plodia), represents an alternative silk source that is easily reared in highly regulated culture environments allowing for greater consistency in the silk produced. We controlled the temperature, resource availability (larvae/gram diet), and population density (larvae/mL) with the goal of increasing silk fiber production and improving homogeneity in Plodia silk proteins. We determined that higher temperatures accelerated insect growth and reduced life cycle length. Furthermore, we established initial protocols for the production of Plodia silk with optimal silk production occurring at 24 °C, with a resource availability of 10 larvae/gram and a population density of 0.72 larvae/mL. Population density was shown to be the most prominent driving force of Plodia silk mat formation among the three parameters assessed. Future work will need to link gene expression, protein production and purification, and resulting mechanical properties as a function of environmental cues to further transition Plodia silk into regenerated silk fibroin biomaterials.


Assuntos
Bombyx , Fibroínas , Animais , Seda/metabolismo , Bombyx/genética , Materiais Biocompatíveis , Fenômenos Mecânicos
19.
Heliyon ; 10(5): e26576, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38434386

RESUMO

Members of Sarcophagidae are necrophagous and are commonly found on decaying carcasses; and their developmental forms are important indicators for the approximation of lowest postmortem interval (PMImin). This work describes the biological characteristics of Sarcophaga argyrostoma from Tehran, Iran. Various temperature regimes were applied to estimate the thermal summation constant (k) and thermal requirements for development of S. argyrostoma. Five growth proceedings, containing 1st ecdysis, 2nd ecdysis, wandering, pupariation and eclosion, were investigated under eight fixed temperature regimes (6-30 °C). The effects of fly age, freshness, and availability of oviposition substrate on oviparity and viviparity was studied. At 6 °C, no development occurs, and at 8 °C only the first ecdysis occurs. At temperatures between 10 and 30 °C, all immature stages proceeded to the adult stage, and thus immature development was analyzed at these six remaining temperatures. The development phases needed minimum (Dz ± SE) 5.4(0.4), 8.5(0.26), 5.3(0.44), 3.8(0.1), and 6.6 (0.6)°C to attain one of the succeeding developmental occasion, correspondingly. The approximated K for those five occasions were 15.04 ± 1.12, 12.62 ± 0.65, 140.36 ± 4.35, 14.59 ± 0.6, and 222.8 ± 4.18°-day (DD) accordingly. When the food substrate is available and fresh, the female prefers to lay eggs, no matter how old she is. However, the chance of ovoviviparity increased when no oviposition substrate was available. The truth that S. argyrostoma able to either larviposit or to lay eggs encompasses serious consequences for the precise estimation of the PMImin, as the existence of larvae resulting from eggs laid on the carcass could add hours (based on ambient temperature) to the PMImin.

20.
PeerJ ; 12: e16782, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38435990

RESUMO

Ants belonging to the Monomorium indicum (Formicidae: Hymenoptera) species are ubiquitous insects that are commonly associated with household settings in Pakistan. Packaged foodstuffs are easily destroyed by household ants when packaging is made with materials that have a high susceptibility. This study evaluated the susceptibility of three common flexible plastic packaging materials namely: opaque polyethylene, transparent polyethylene and polypropylene, which were each tested at thicknesses of 0.02 mm for their susceptibility against M. indicum. Except opaque polyethylene which is only available at 0.02 mm thickness, both transparent polyethylene and polypropylene were tested at higher thickness of 0.04 mm and 0.06 mm also against M. indicum. In order to simulate household settings, experiments were conducted at the faculty building of the agriculture and environment department of The Islamia University of Bahawalpur, Pakistan during summer vacations when the building was quiet. Different corners were selected near water sources for maximum exposure to the largest number of ants. Experimental cages used for the experiment were built with wood and 2 mm iron gauze to allow only ants to enter the cages. Daily activity of ants was used as an infestation source in cages. Experiments were run over three time spans of fifteen days each from June 20th 2022 to August 15th 2022. Results showed all packaging materials were susceptible against M. indicum at the 0.02 mm thickness level. Polypropylene was susceptible at 0.04 mm thickness but resistant to ants at 0.06 mm thickness, whereas polyethylene was still susceptible to ants at the higher thickness of 0.06 mm. Correlation of packaging damage with weather factors showed that temperature had a positive relationship, while relative humidity had a negative association with M. indicum attack. Overall correlation of packaging damage with packaging thickness showed packaging thickness was negatively associated with packaging damage from the ants. Because major cutting role is performed by the mandibles, we studied mandibles of ants and three frequent pests of packaged foodstuff namely Rhyzopertha dominica, Tribolium castaneum and Trogoderma granarium. The results showed that ants had the largest mandible and frontal mandibular tooth lengths compared with the mandibles and frontal teeth of the common stored product pests, indicating M. indicum household ants have a higher pest status for packaged foodstuffs compared to common stored product pests. Although the thickness of the flexible plastic packaging was a major factor against household ants, the study results recommend the use of polypropylene with a thickness of at least 0.06 mm as foodstuff packaging against household ants compared with polyethylene packaging, which was found to be susceptible to ants even at 0.06 mm thickness.


Assuntos
Formigas , Besouros , Animais , Polipropilenos , Polietileno
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