Insects

11 pages, 891 KiB

Open AccessArticle

New Strains of the Entomopathogenic Nematodes Steinernema scarabaei, S. glaseri, and S. cubanum for White Grub Management

by Albrecht M. Koppenhöfer and Ana Luiza Sousa

Insects 2024, 15(12), 1022; https://doi.org/10.3390/insects15121022 - 23 Dec 2024

Viewed by 534

Abstract

White grubs possess natural defense mechanisms against entomopathogenic nematodes (EPNs). Hence, EPN isolates that naturally infect white grubs tend to be among the most effective biological control agents of white grubs. We tested the virulence of four EPN isolates recently isolated from infected [...] Read more.

White grubs possess natural defense mechanisms against entomopathogenic nematodes (EPNs). Hence, EPN isolates that naturally infect white grubs tend to be among the most effective biological control agents of white grubs. We tested the virulence of four EPN isolates recently isolated from infected white grubs in turfgrass areas in central New Jersey, USA against third-instar larvae of Anomala orientalis, Popillia japonica, and Cyclocephala borealis, which are pests of turfgrass and ornamental plants in the northeastern USA. Against A. orientalis and P. japonica larvae, the Steinernema scarabaei Ad and S. scarabaei SL isolates were highly virulent in laboratory tests, whereas S. cubanum HF was less virulent and S. glaseri SH the least virulent. None of the isolates caused high mortality of C. borealis larvae. EPN efficacy in greenhouse tests against A. orientalis followed the same pattern. The original isolate of S. scarabaei, the AMK001 strain, that had been maintained in the laboratory on A. orientalis and P. japonica larvae for 19 years showed the same virulence level against A. orientalis larvae as it did soon after its first isolation and was also as virulent as the fresh S. scarabaei Ad isolate; both isolates were more virulent than S. scarabaei SL. Future tests should determine the ability of these white grub-adapted isolates to provide long-term suppression of white grub populations. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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43 pages, 2914 KiB

Open AccessArticle

Insect Decline—Evaluation of Potential Drivers of a Complex Phenomenon

by Michael E. Grevé, Michael Thomas Marx, Sascha Eilmus, Matthias Ernst, John D. Herrmann, Christian Ulrich Baden and Christian Maus

Insects 2024, 15(12), 1021; https://doi.org/10.3390/insects15121021 - 23 Dec 2024

Viewed by 2516

Abstract

The decline of insects is a global concern, yet identifying the factors behind it remains challenging due to the complexity of potential drivers and underlying processes, and the lack of quantitative historical data on insect populations. This study assesses 92 potential drivers of [...] Read more.

The decline of insects is a global concern, yet identifying the factors behind it remains challenging due to the complexity of potential drivers and underlying processes, and the lack of quantitative historical data on insect populations. This study assesses 92 potential drivers of insect decline in West Germany, where significant declines have been observed. Using data from federal statistical offices and market surveys, the study traces changes in landscape structure and agricultural practices over 33 years. Over the years, the region underwent major landscape changes, including reduced cropland and grassland and increased urbanization and forest areas. Potential detected drivers of insect decline include: (1) urban expansion, reducing insect habitats as urban areas increased by 25%; (2) intensified grassland management; (3) shifts in arable land use towards bioenergy and feed crop cultivation, particularly corn, driven by dairy farming intensification and renewable energy policies. While the toxic load of pesticide application has decreased, land-use changes, most likely driven by market demands and shifts in national and EU policies, have reduced habitat availability and suitability for insects. This study highlights how these landscape and land management changes over the past 33 years align with the observed decline in insect biomass in the region. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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11 pages, 2061 KiB

Open AccessArticle

Genetic Diversity and Differentiation of Silkworm (Bombyx mori) Local Germplasm Resources in China and Uzbekistan

by Xia Xu, Xin Du, Jine Chen, Lusong Yao, Xiuling He, Linbao Zhu, Shaofang Yu, Valiev Sayfiddin Tojiddinovich, Baxtiyar Ubaydullayevich Nasirillayev, Ismatullaeva Diloram Adilovna, Khudjamatov Safarali Khasanboy ugl and Yongqiang Wang

Insects 2024, 15(12), 1020; https://doi.org/10.3390/insects15121020 - 23 Dec 2024

Viewed by 517

Abstract

Silkworm (Bombyx mori) is an economically significant insect that produces silk and makes important contributions to the development of silk-producing countries. The genetic diversity and unique adaptive traits of silkworm germplasm resources form the foundation for breeding efforts. In various geographical [...] Read more.

Silkworm (Bombyx mori) is an economically significant insect that produces silk and makes important contributions to the development of silk-producing countries. The genetic diversity and unique adaptive traits of silkworm germplasm resources form the foundation for breeding efforts. In various geographical regions, silkworm have developed distinct traits through long-term adaptive selection. In this study, we focused on identifying and evaluating representative silkworm germplasm resources from both China and Uzbekistan. We discovered notable differences in the morphology and production traits of local silkworm strains, likely influenced by differing geographical environments. It is also possible that China has a long history of silkworm rearing and after a long time of breeding selection, the diversity of silkworm morphology is less than that of Uzbekistan, but the production characteristics are more suitable for silk utilization. Phylogenetic analysis based on genomic comparisons revealed that Uzbekistan’s local silkworm strains are positioned between China’s local and improved strains. This suggests that Uzbekistan silkworms primarily originated from China. The further analysis of genetic diversity and strain differentiation highlights the unique differences of each country’s silkworms, especially in terms of genetic diversity on chromosome 1 (sex chromosome). By identifying and evaluating these germplasm resources and linking them to unique advantageous traits, it provides a scientific basis for improving cocoon silk quality and optimizing sericulture productivity. Full article

(This article belongs to the Special Issue Genomics and Molecular Biology in Silkworm)

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13 pages, 9076 KiB

Open AccessArticle

Antimicrobial Activity of Compounds Isolated from the Nest Material of Crematogaster rogenhoferi (Mayr) (Hymenoptera: Formicidae)

by Weihui Bai, Baihe Chen, Huimei Chen, Lei Nie, Mingrong Liang, Yijuan Xu, Yongyue Lu and Lei Wang

Insects 2024, 15(12), 1019; https://doi.org/10.3390/insects15121019 - 23 Dec 2024

Viewed by 466

Abstract

Ants as social insects live in groups, which increases the risk of contagious diseases. In response to the threat of pathogens, ants have evolved a variety of defense mechanisms, including incorporating antimicrobial chemicals into nest material for nest hygiene. Crematogaster rogenhoferi is an [...] Read more.

Ants as social insects live in groups, which increases the risk of contagious diseases. In response to the threat of pathogens, ants have evolved a variety of defense mechanisms, including incorporating antimicrobial chemicals into nest material for nest hygiene. Crematogaster rogenhoferi is an arboreal ant, building its nest using plant tissues. It is still unclear how C. rogenhoferi is protected against pathogens in its nest. Two main chemicals, 2,2′-methylenebis[6-(1,1-dimethylethyl)-4-methyl-phenol] (MP) and lup-20(29)-en-3-one (LP), isolated from nest materials of C. rogenhoferi were used to investigate ants’ anti-pathogenic activity against the entomopathogenic fungus Beauveria bassiana and the entomopathogenic bacteria Serratia marcescens. The results showed that MP and LP can inhibit the growth of B. bassiana through direct contact and fumigation. However, neither MP nor LP had any negative effect on S. marcescens growth. Subsequent analysis showed that MP was found in both the abdomen part and the head part of C. rogenhoferi workers, and LP was not detected in C. rogenhoferi workers. Since LP is a common plant secondary metabolite, it is implied that LP may originate from the plant tissue of C. rogenhoferi nest materials. Our results showed that C. rogenhoferi capitalizes on its own antimicrobial chemicals and probably the chemical defenses which have evolved in plants to protect itself against pathogens. Full article

(This article belongs to the Collection Insect Immunity: Evolution, Genomics and Physiology)

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9 pages, 7514 KiB

Open AccessArticle

Davimacrocera, a New Extant Genus of Keroplatidae, with Notes on the Fossil Genus Burmacrocera (Diptera)

by Jan Ševčík

Insects 2024, 15(12), 1018; https://doi.org/10.3390/insects15121018 - 22 Dec 2024

Viewed by 782

Abstract

A new extant genus of Keroplatidae (Diptera: Bibionomorpha), Davimacrocera gen. nov., is described in this paper, which includes two new species, Davimacrocera davidi sp. nov. (Brunei, type species of the genus) and D. taiwanensis sp. nov. (Taiwan, China). Its relationships to other extant [...] Read more.

A new extant genus of Keroplatidae (Diptera: Bibionomorpha), Davimacrocera gen. nov., is described in this paper, which includes two new species, Davimacrocera davidi sp. nov. (Brunei, type species of the genus) and D. taiwanensis sp. nov. (Taiwan, China). Its relationships to other extant genera and possible phylogenetic position are briefly discussed, including a comparison with the fossil genus Burmacrocera Cockerell, 1917 from the mid-Cretaceous amber of Myanmar. The identity of Burmacrocera remains unclear, pending further studies of Keroplatidae in Burmese amber. Full article

(This article belongs to the Special Issue Revival of a Prominent Taxonomy of Insects)

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25 pages, 729 KiB

Open AccessReview

Entomopathogenic Fungi as Alternatives to Chemical Acaricides: Challenges, Opportunities and Prospects for Sustainable Tick Control

by Mahvish Rajput, Muhammad Sohail Sajid, Nasir Ahmed Rajput, David Robert George, Muhammad Usman, Muhammad Zeeshan, Owais Iqbal, Bachal Bhutto, Muhammad Atiq, Hafiz Muhammad Rizwan, Ian Kirimi Daniel and Olivier Andre Sparagano

Insects 2024, 15(12), 1017; https://doi.org/10.3390/insects15121017 - 22 Dec 2024

Viewed by 656

Abstract

Entomopathogenic fungi (EPFs) can infect and kill a diverse range of arthropods, including ticks (Acari: Ixodidae) that can transmit various diseases to animals and humans. Consequently, the use of EPFs as a biocontrol method for managing tick populations has been explored as an [...] Read more.

Entomopathogenic fungi (EPFs) can infect and kill a diverse range of arthropods, including ticks (Acari: Ixodidae) that can transmit various diseases to animals and humans. Consequently, the use of EPFs as a biocontrol method for managing tick populations has been explored as an alternative to chemical acaricides, which may have harmful effects on the environment and non-target species. This review summarizes studies conducted on EPFs for tick control between 1998 and 2024, identifying 9 different EPF species that have been used against 15 different species of ticks. One of the most well-known and widely researched EPFs used against ticks is Metarhizium anisopliae, a fungus known for its ability to infect and kill various arthropods. When applied to tick-infested areas, M. anisopliae spores attach to the tick’s cuticle, germinate, and penetrate through the cuticle, leading to the eventual death of the tick due to the fungal infection. Whilst a number of studies support the potential of this and other EPF species against ticks, this review suggests that limitations to their effective use may include factors such as heat, humidity, and ultraviolet light (UV-A and UV-B). This comprehensive review aims to provide an overview of the literature on the potential of EPFs in tick control, focusing on their mode of action, previous field successes/failures, advantages, potential applications, and prospects for future practical developments. Full article

(This article belongs to the Section Insect Behavior and Pathology)

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13 pages, 7062 KiB

Open AccessArticle

Expression of Drosophila melanogaster V-ATPases in Olfactory Sensillum Support Cells

by Kalpana Jain, Sinisa Prelic, Bill S. Hansson and Dieter Wicher

Insects 2024, 15(12), 1016; https://doi.org/10.3390/insects15121016 - 22 Dec 2024

Viewed by 542

Abstract

V-ATPases are ubiquitous and evolutionarily conserved rotatory proton pumps, which are crucial for maintaining various biological functions. Previous investigations have shown that a V-ATPase is present in the support cells of moth trichoid sensilla and influences their olfactory sensory neuron performance. Generally, V-ATPases [...] Read more.

V-ATPases are ubiquitous and evolutionarily conserved rotatory proton pumps, which are crucial for maintaining various biological functions. Previous investigations have shown that a V-ATPase is present in the support cells of moth trichoid sensilla and influences their olfactory sensory neuron performance. Generally, V-ATPases are thought to regulate the pH value within the sensillum lymph, and aid K⁺ homeostasis within the sensillum. This, in turn, could influence various mechanisms involved within the support cells, like maintaining the receptor membrane potential (receptor current), nutrient and ion transport, odorant solubility, and various signaling mechanisms. In this study, we identify V-ATPase expression and localization in the Drosophila melanogaster antenna using bioinformatics and immunohistochemistry. Elucidating an olfactory V-ATPase function will improve our current understanding of how support cells contribute to Drosophila’s sense of smell. Full article

(This article belongs to the Collection Insect Sensory Biology)

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15 pages, 11046 KiB

Open AccessArticle

The First Report of the Aphid Genus Macromyzus (Hemiptera: Aphididae) from Laos, with a Description of a New Species and Its Taxonomic Position

by Minho Lee, Mariusz Kanturski, Chitpasong Santammavong and Seunghwan Lee

Insects 2024, 15(12), 1015; https://doi.org/10.3390/insects15121015 - 22 Dec 2024

Viewed by 461

Abstract

In this paper, the aphid genus Macromyzus Takahashi, 1960 is reported for the first time from Laos. A detailed description of the apterous viviparous female of a new species, Macromyzus (Macromyzus) diplazius sp. nov. associated with Diplazium esculentum is provided. For [...] Read more.

In this paper, the aphid genus Macromyzus Takahashi, 1960 is reported for the first time from Laos. A detailed description of the apterous viviparous female of a new species, Macromyzus (Macromyzus) diplazius sp. nov. associated with Diplazium esculentum is provided. For the first time, we conduct scanning electron microscopy (SEM) to examine the morphology and sensilla (antennae, mouthparts, and legs) of the representative of this genus. Furthermore, we update the taxonomic definition of the subgenus Macromyzus based on morphological characteristics, discuss the taxonomic position of the new species, and provide an identification key to all known Macromyzus species. Full article

(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)

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15 pages, 3307 KiB

Open AccessArticle

Lack of Vertical Transmission of Grapevine Red Blotch Virus by Spissistilus festinus and Sex-Associated Differences in Horizontal Transmission

by Victoria J. Hoyle, Mackenzi Schultz, Elliot J. McGinnity Schneider, Brandon G. Roy and Marc Fuchs

Insects 2024, 15(12), 1014; https://doi.org/10.3390/insects15121014 - 21 Dec 2024

Viewed by 507

Abstract

Grapevine red blotch is an emerging disease that threatens vineyard productions in North America. Grapevine red blotch virus (GRBV, species Grablovirus vitis, genus Grablovirus, family Geminiviridae), the causal agent of red blotch disease, is transmitted by Spissistilus festinus (Hemiptera: Membracidae) [...] Read more.

Grapevine red blotch is an emerging disease that threatens vineyard productions in North America. Grapevine red blotch virus (GRBV, species Grablovirus vitis, genus Grablovirus, family Geminiviridae), the causal agent of red blotch disease, is transmitted by Spissistilus festinus (Hemiptera: Membracidae) in a circulative, non-propagative mode. To gain new insight into GRBV-S. festinus interactions, we delved into vertical transmission and documented a lack of transovarial transmission. In addition, we investigated S. festinus sex differences in the horizontal transmission of GRBV by creating small arenas with 30 detached trifoliates of common snap bean, an experimental host of GRBV, and a preferred feeding host of S. festinus. Tracking the movement of viruliferous males, females, or a combination of the two sexes over two weeks in replicated experiments demonstrated that male S. festinus dispersed more than females with specimens of both sexes predominantly grouping together on trifoliates spatially surrounding the trifoliate onto which they were released. These behaviors resulted in a greater rate of GRBV transmission by S. festinus males (17%, 20 of 120) than females (4%, 5 of 120) or mixed-sex cohorts (9%, 17 of 180). In arenas with aviruliferous S. festinus and one (single) or four (hotspot) GRBV-infected trifoliates out of 30 total trifoliates, a higher GRBV transmission rate by males was confirmed in both single infection (50%, 30 of 60) and hotspot infection (83%, 50 of 60) arenas than by females in single infection (35%, 21 of 60) and hotspot infection (67%, 40 of 60) arenas. These findings highlighted sex-associated differences in the transmission of GRBV by S. festinus and a positive correlation between the initial virus prevalence and the rate of transmission. Finally, the secondary spread of GRBV resulted primarily from S. festinus dispersal by walking or jumping. Together, these unique GRBV transmission features support the need to characterize dispersal behaviors of S. festinus in vineyard ecosystems. Full article

(This article belongs to the Special Issue Plant–Insect Vector–Pathogen Interactions)

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11 pages, 3865 KiB

Open AccessArticle

Determination of Larval Instars of Dastarcus helophoroides (Coleoptera: Bothrideridae) Using Head Capsule Width Frequency Distribution

by Tayyab Shaheen, Jiali Guo, Yun Wang, Jiaojiao Zhou, Guanghui Tang and Zhengqing Zhang

Insects 2024, 15(12), 1013; https://doi.org/10.3390/insects15121013 - 20 Dec 2024

Viewed by 563

Abstract

Long-horned beetles are among the major insect pests that can cause significant economic and ecological damage globally. The control of long-horned beetles is crucial to sustain the forest ecosystem. Dastarcus helophoroides, an economically important ectoparasitoid of long-horned beetles, is widely utilized in [...] Read more.

Long-horned beetles are among the major insect pests that can cause significant economic and ecological damage globally. The control of long-horned beetles is crucial to sustain the forest ecosystem. Dastarcus helophoroides, an economically important ectoparasitoid of long-horned beetles, is widely utilized in biological control strategies. However, the number of larval instars in D. helophoroides remains underexplored. Larval instar determination is crucial for constructing growth prediction models and ecological life tables for insect populations. In this study, we analyzed the frequency distribution of head capsule widths utilizing a visual approach, followed by a non-linear least squares (NLLS) estimation, and found that D. helophoroides undergo four larval instars before entering the pupal stage. The theoretical and observed data for each larval instar yielded identical mean Brooks–Dyar’s ratios (1.80). Re-correlation of the number of instars with their respective mean head capsule widths using linear regression (R²) verified that no larval instar was missed. The Crosby’s growth ratio (1% and 2%) indicates a very low likelihood of misclassifying an instar into an adjacent one. Given that the accurate determination of larval instars is crucial for developing effective control programs and predicting future population levels, our findings provide valuable insights for implementing biological control strategies against long-horned beetles. Full article

(This article belongs to the Special Issue Revival of a Prominent Taxonomy of Insects)

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20 pages, 13788 KiB

Open AccessArticle

Predicting the Potential Distribution of Cheirotonus jansoni (Coleoptera: Scarabaeidae) Under Climate Change

by Yali Yu and Zhiqiang Li

Insects 2024, 15(12), 1012; https://doi.org/10.3390/insects15121012 - 20 Dec 2024

Viewed by 500

Abstract

Cheirotonus jansoni (Jordan, 1898), a beetle species of ecological and ornamental significance, is predominantly found in southern China. With limited dispersal ability, it is classified as a Class 2 protected species in China. In this study, the widely employed maximum entropy (MaxEnt) model [...] Read more.

Cheirotonus jansoni (Jordan, 1898), a beetle species of ecological and ornamental significance, is predominantly found in southern China. With limited dispersal ability, it is classified as a Class 2 protected species in China. In this study, the widely employed maximum entropy (MaxEnt) model and the ensemble Biomod2 model were applied to simulate C. jansoni habitat suitability in China under current environmental conditions based on available distribution data and multiple environmental variables. The optimized MaxEnt model demonstrated improved accuracy and robust predictive capabilities, making it the preferred choice for simulating dynamic changes in potentially suitable habitats for C. jansoni under future climate scenarios. Protection gaps were further identified through analyses of the overlap between nature reserves and highly suitable areas for C. jansoni. The established models indicated that this species primarily resides in southeastern mountainous regions of China below 2000 m, with a preferred altitude of 1000–2000 m. Future climate scenarios suggest a reduction in the overall suitable habitat for C. jansoni with an increase in temperature, underscoring the urgent need for enhanced conservation efforts for this beetle species. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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22 pages, 6100 KiB

Open AccessArticle

Ant-Plant Mutualism in Mauritia flexuosa Palm Peat Swamp Forests: A Study of Host and Epiphyte Diversity in Ant Gardens

by Yakov Quinteros-Gómez, Jehoshua Macedo-Bedoya, Abel Salinas-Inga, Flavia Anlas-Rosado, Victor Santos-Linares, Geancarlo Alarcon-Iman, Doris Gómez-Ticerán, Franco Angeles-Alvarez, Sergio Olórtegui-Chamolí, Julio Solis-Sarmiento, Enoc Jara-Peña and Octavio Monroy-Vilchis

Insects 2024, 15(12), 1011; https://doi.org/10.3390/insects15121011 - 20 Dec 2024

Viewed by 577

Abstract

Mutualisms characterized by reciprocal benefits between species are a fundamental relationship of tropical ecosystems. Ant Gardens (AGs) represent an interesting ant-plant mutualism, involving specialized interactions between vascular epiphytes and ants. While this relationship has been extensively studied in various tropical regions, the available [...] Read more.

Mutualisms characterized by reciprocal benefits between species are a fundamental relationship of tropical ecosystems. Ant Gardens (AGs) represent an interesting ant-plant mutualism, involving specialized interactions between vascular epiphytes and ants. While this relationship has been extensively studied in various tropical regions, the available information on Peruvian ecosystems is limited. The objective of this study was to identify the ant and epiphyte species that constitute AGs. From February 2023 to January 2024, a study was conducted on two 50 × 10 m transects within the Mauritia flexuosa peat swamp forest, located within the Water Association Aguajal Renacal del Alto Mayo (ADECARAM) Tingana in San Martín, Peru. A total of 69 ant gardens were documented, comprising 18 phorophyte species, 19 epiphyte species, and three ant species. The results demonstrated that neither the height nor the diameter at breast height (DBH) of phorophytes exhibited a statistically significant correlation with the number of AGs per host. However, a positive correlation was observed between the length and width of the AGs and the number of ants per AG. The findings of this study contribute to the understanding of AG mutualism in Peruvian ecosystems. Full article

(This article belongs to the Special Issue Ecologically Important Symbioses in Insects)

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16 pages, 7129 KiB

Open AccessArticle

Genomic Analysis Reveals Novel Genes and Adaptive Mechanisms for Artificial Diet Utilization in the Silkworm Strain Guican No.5

by Lei Xin, Delong Guan, Nan Wei, Xiaoyan Zhang, Weian Deng, Xiaodong Li and Jing Song

Insects 2024, 15(12), 1010; https://doi.org/10.3390/insects15121010 - 20 Dec 2024

Viewed by 577

Abstract

The transition from traditional mulberry leaf feeding to artificial diet cultivation represents a major advancement in modern sericulture, yet the genetic mechanisms driving this adaptation remain largely unexplored. This study investigates the genomic basis of artificial diet adaptation in the silkworm strain Guican [...] Read more.

The transition from traditional mulberry leaf feeding to artificial diet cultivation represents a major advancement in modern sericulture, yet the genetic mechanisms driving this adaptation remain largely unexplored. This study investigates the genomic basis of artificial diet adaptation in the silkworm strain Guican No.5 through whole-genome resequencing and transcriptome analysis. We identified 8,935,179 single-nucleotide polymorphisms (SNPs) across all chromosomes, accounting for 2.01% of the genome, with particularly high densities observed in chromosomes 23, 26, and 28. Our analysis also revealed 879 novel transcripts, many of which are involved in digestion, detoxification, and stress response pathways. Key novel genes, including three carboxylesterases, two cytochrome P450s, one heat shock protein, and one copper/zinc superoxide dismutase, exhibited varying degrees of sequence similarity to known proteins, suggesting modifications to existing genetic frameworks. Notably, one novel P450 gene displayed only 74.07% sequence identity with its closest homolog, indicating the emergence of a new protein sequence. Additionally, several key genes showed high similarity to wild silkworm (Bombyx mandarina) proteins, underscoring their evolutionary origins. These findings provide valuable insights into the molecular mechanisms underpinning artificial diet adaptation in silkworms and offer genomic resources to enhance artificial diet formulations and breeding programs in sericulture. Full article

(This article belongs to the Special Issue Genomics and Molecular Biology in Silkworm)

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15 pages, 2567 KiB

Open AccessArticle

Wild Bee Diversity and Bee–Plant Interactions in Tropical and Temperate Forest Clearings in a Natural Protected Area in Central West Mexico

by Alvaro Edwin Razo-León, Alejandro Muñoz-Urias, Claudia Aurora Uribe-Mú, Francisco Martín Huerta-Martínez, Hugo Eduardo Fierros-López, Miguel Vásquez-Bolaños, Gustavo Moya-Raygoza and Pablo Carrillo-Reyes

Insects 2024, 15(12), 1009; https://doi.org/10.3390/insects15121009 - 20 Dec 2024

Viewed by 830

Abstract

Background: Bees rely on plants for nutrition and reproduction, making the preservation of natural areas crucial as pollinator reservoirs. Seasonal tropical dry forests are among the richest habitats for bees, but only 27% of their original extent remains in Mexico. In contrast, temperate [...] Read more.

Background: Bees rely on plants for nutrition and reproduction, making the preservation of natural areas crucial as pollinator reservoirs. Seasonal tropical dry forests are among the richest habitats for bees, but only 27% of their original extent remains in Mexico. In contrast, temperate forests harbor fewer bee species and face high deforestation rates, with 40% of their area converted to other land uses. This study aimed to estimate the α and β diversities of wild bees and compare bee–plant interaction networks between these two vegetation types. Methods: Wild bees and their interactions with plants were monitored for one year in four sites within the Área de Protección de Flora y Fauna Sierra de Quila. Two sites corresponded to seasonal tropical dry forest and two to temperate forest. α and β diversity, connectance, nestedness, web asymmetry, and niche overlap were analyzed. Results: Sierra de Quila harbors high bee diversity, with 155 species in tropical dry forest and 103 in temperate forest. Species turnover between vegetation types was high, although nine species used floral resources in both forests, connecting the interaction networks. Conclusions: Sierra de Quila diverse habitats promote high bee diversity, with niche partitioning and low connectance facilitating coexistence across different vegetation types. Full article

(This article belongs to the Section Social Insects)

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16 pages, 4247 KiB

Open AccessArticle

Rapid and Accurate Detection of Chrysomya megacephala (Diptera: Calliphoridae) Using Recombinase Polymerase Amplification Combined with Lateral Flow Dipstick

by Chengxin Ye, Xuan Tang, Fengqin Yang, Xiangyan Zhang, Yanjie Shang, Yang Xia, Yuanxing Wang, Shaojiang Guo, Lagabaiyila Zha, Yadong Guo and Dan Wen

Insects 2024, 15(12), 1008; https://doi.org/10.3390/insects15121008 - 20 Dec 2024

Viewed by 581

Abstract

Estimating the postmortem interval (PMI) is critical in the field of forensic science, and necrophagous insects play a significant role in this process. Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) is a common necrophagous insect species, making its rapid and accurate identification essential. However, commonly [...] Read more.

Estimating the postmortem interval (PMI) is critical in the field of forensic science, and necrophagous insects play a significant role in this process. Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) is a common necrophagous insect species, making its rapid and accurate identification essential. However, commonly used molecular biology methods, such as DNA barcode, still have some limitations in identifying necrophagous insects as they are often complex, time-consuming, and reliant on laboratory instruments. Therefore, in this study, we have developed an innovative detection system for the rapid and accurate identification of C. megacephala based on the Cytochrome b gene using recombinase polymerase amplification (RPA) and lateral flow dipstick (LFD) in combination. The developed RPA-LFD detection system achieved complete amplification in just 15 min at 37 °C with good sensitivity and specificity. Only 7.8 × 10⁻⁴ ng or more of target DNA fragments were required, and a positive detection rate of 100% was achieved in 18 C. megacephala samples from actual cases. In addition, the ability of the developed RPA-LFD detection system in combination with rapid DNA extraction methods to enable on-site detection was preliminarily explored. The results suggested that when the RPA-LFD detection system was combined with the grinding ddH₂O extraction method (a rapid DNA extraction method), the process from species acquisition to visualization of detection results could be completed in less than 20 min. In conclusion, this innovative RPA-LFD detection system outperforms commonly used molecular biology methods for C. megacephala identification in terms of speed, sensitivity and convenience, making it suitable for direct application at crime scenes, promising to provide important assistance in estimating PMI and expanding the impact of forensic entomological evidence. Full article

(This article belongs to the Special Issue Forensic Entomology: From Basic Research to Practical Applications)

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9 pages, 1471 KiB

Open AccessArticle

De Novo miRNAs from Anisopteromalus calandrae (Hymenoptera: Pteromalidae) Conserved in the Order Hymenoptera

by Mariana Lizbeth Jiménez-Martínez, María de Lourdes Ramírez-Ahuja, Daniel Rafael Saldaña-Torres, Margarita L. Martinez-Fierro, Ivan Delgado-Enciso, Adriana E. Flores-Suarez, Diana Reséndez-Pérez, Antonio Guzmán-Velasco and Iram Pablo Rodríguez-Sánchez

Insects 2024, 15(12), 1007; https://doi.org/10.3390/insects15121007 - 20 Dec 2024

Viewed by 690

Abstract

The parasitoid wasp Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) has the potential for biological control against insect pests in stored grains, mainly of the orders Coleoptera and Lepidoptera. microRNAs (miRNAs) are small non-coding RNA fragments of importance in the regulation of gene translation in [...] Read more.

The parasitoid wasp Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) has the potential for biological control against insect pests in stored grains, mainly of the orders Coleoptera and Lepidoptera. microRNAs (miRNAs) are small non-coding RNA fragments of importance in the regulation of gene translation in most physiological processes, and the study of miRNAs in wasps can be useful for understanding the physiology of these insects. The objective of this study was to evaluate for the first time the miRNomic profile of A. calandrae and to determine its conservation in five species of the order Hymenoptera (Apis mellifera, Dinoponera quadriceps, Nasonia giraulti, N. longicornis and N. vitripennis). Using molecular techniques and bioinformatics tools, a total of 108 miRNAs were identified (75 conserved between species and 34 de novo). These miRNAs were found to be related to embryogenesis, signaling, metabolic, biological and immune functions. The miRNomic signature of A. calandrae is important for the study of the physiology of wasps and the order Hymenoptera. Full article

(This article belongs to the Section Insect Molecular Biology and Genomics)

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15 pages, 4821 KiB

Open AccessArticle

Alternative Splicing and Alternative Polyadenylation-Regulated Cold Stress Response of Apis cerana

by Yuanchan Fan, Dan Yao, Jinmeng Ma, Fangdong You, Xiaoping Wei and Ting Ji

Insects 2024, 15(12), 1006; https://doi.org/10.3390/insects15121006 - 19 Dec 2024

Viewed by 683

Abstract

Temperature is a pivotal ecological factor in the regulation of insect survival and reproduction [...] Full article

(This article belongs to the Special Issue Biology and Conservation of Honey Bees)

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14 pages, 1463 KiB

Open AccessArticle

by Jisheng Liu, Weijian Chen, Sihua Chen, Shuqiang Li and Luc Swevers

Insects 2024, 15(12), 1005; https://doi.org/10.3390/insects15121005 - 19 Dec 2024

Viewed by 506

Abstract

Toll receptors play important roles in the development and innate immunity of insects. Previously, we reported the immunological function of BmToll9-2 in silkworm, Bombyx mori, larvae. In this study, we focused on the role of BmToll9-2 as a regulator in the Toll [...] Read more.

Toll receptors play important roles in the development and innate immunity of insects. Previously, we reported the immunological function of BmToll9-2 in silkworm, Bombyx mori, larvae. In this study, we focused on the role of BmToll9-2 as a regulator in the Toll signaling pathway. The expressions of most signaling genes in the Toll pathway, as well as immune effectors, were reduced after the RNAi of BmToll9-2. Coincidentally, hemolymph from BmToll9-2-silenced larvae exhibited decreased antibacterial activity in the growth of Escherichia coli, demonstrated either by growth curve or inhibitory zone experiments. The oral administration of heat-inactivated E. coli and Staphylococcus aureus following the RNAi of BmToll9-2 up-regulated the expression of most signaling genes in the Toll pathway and downstream immune effectors. The above results indicate that BmToll9-2 is positively involved in the Toll signaling pathway. As a positive regulator, BmToll9-2 is shown to be activated preferentially against E. coli and, in turn, positively modulates the humoral immune response in antibacterial activity. Full article

(This article belongs to the Collection Insect Immunity: Evolution, Genomics and Physiology)

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8 pages, 633 KiB

Open AccessBrief Report

Larval Feeding Habits of Five Firefly Species Across Aquatic, Semi-Aquatic, and Terrestrial Lineages

by Lin-Yu Yang, Da-Rui Tang, Fu-Xin Li, Shi-Qi Luo, Cheng-Quan Cao and Qi-Lin Zhang

Insects 2024, 15(12), 1004; https://doi.org/10.3390/insects15121004 - 18 Dec 2024

Viewed by 520

Abstract

While adult fireflies are terrestrial, their larvae inhabit various habitat types, and a lack of comprehensive research on the feeding habits of these larvae across different habitats has greatly impeded the development of artificial diets. Here, we tested 14 types of foods, primarily [...] Read more.

While adult fireflies are terrestrial, their larvae inhabit various habitat types, and a lack of comprehensive research on the feeding habits of these larvae across different habitats has greatly impeded the development of artificial diets. Here, we tested 14 types of foods, primarily covering gastropods, vertebrates, and fruit, to survey feed for aquatic (Aquatica leii and Sclerotia substriata), semi-aquatic (Pygoluciola qingyu and Pygoluciola sp.), and terrestrial (Pyrocoelia analis) fireflies. The results show that A. leii, S. substriata, P. qingyu, Pygoluciola sp., and P. analis fed on 12, 6, 10, 10, and 7 different foods, respectively, showing an obvious difference in feeding range among various inhabit types of fireflies. Aquatic lineages preferred to consume freshwater snails, followed by pork meat and land slugs, while semi-aquatic fireflies favored freshwater snails, followed by fish and shrimp. Favorite foods were thus freshwater snails such as Cipangopaludina chinensis for both aquatic and semi-aquatic fireflies, but feeding preference differed for second favorite foods (e.g., pork vs. fish meat). Terrestrial Pyrocoelia analis showed different feeding preferences compared withthe other two habitat lineages, with terrestrial snails and slugs as their favorite foods, followed by freshwater snails, such as C. chinensis. These findings not only uncovered larval feeding habits of fireflies across various inhabit types but also indicated that readily available and affordable C. chinensis products can serve as wild snail alternatives in the artificial feeding of fireflies. This study is the first to explore the feeding habits of firefly species inhabiting water and land habitat types, adding to the understanding of the feeding characteristics of fireflies. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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12 pages, 3140 KiB

Open AccessArticle

Age-Stage, Two-Sex Life Tables of Megalurothrips usitatus (Bagnall) and Frankliniella intonsa (Trybom) on Different Bean Pods Under Laboratory Conditions: Implications for Their Competitive Interactions

by Mengni Li, Zhengke Peng, Chaosong Guo, Yong Xiao, Fei Yin, Haibin Yuan, Zhenyu Li and Myron P. Zalucki

Insects 2024, 15(12), 1003; https://doi.org/10.3390/insects15121003 - 18 Dec 2024

Viewed by 754

Abstract

As two major pests of cowpea in South China, bean flower thrips [Megalurothrips usitatus (Bagnall)] and flower thrips [Frankliniella intonsa (Trybom)] always occur on the same plant. In this study, the two-sex life table parameters of these two species were investigated [...] Read more.

As two major pests of cowpea in South China, bean flower thrips [Megalurothrips usitatus (Bagnall)] and flower thrips [Frankliniella intonsa (Trybom)] always occur on the same plant. In this study, the two-sex life table parameters of these two species were investigated on three bean pods: cowpea (Vigna unguiculata L. var. Chunqiu Wujiadou), snap bean (Phaseolus vulgaris L. var. Yonglong 3), and green bean (Phaseolus vulgaris L. var. Linghangzhe) using standard cut bean protocols. Longevity of female adult M. usitatus showed no significant difference on cowpea and snap bean, but was shortest on green bean, with the highest fecundity on snap bean, followed by cowpea and green bean. Longevity and fecundity of female adult F. intonsa were both highest on cowpea, followed by snap bean and green bean. On snap bean, the population parameters (R₀, GRR, T) of M. usitatus were higher than F. intonsa, whereas r and λ were not different, suggesting that M. usitatus were more competitive on snap bean. On cowpea, the population parameters (R₀, GRR, r, λ) of F. intonsa were higher than M. usitatus, suggesting a competitive advantage of F. intonsa on cowpea. To better mimic field conditions, we investigated the survival and fecundity of adult M. usitatus under two distinct scenarios: when they could feed directly on cut surfaces of cowpeas (standard lab protocol), and when they could not. Adult survival of M. usitatus is not significantly influenced by whether or not they fed directly on cut surfaces of cowpeas. However, a notable decrease in fecundity was observed in M. usitatus that fed on surface-covered cut pods. This suggested that direct feeding on cut surfaces of cowpea did have an impact on thrips’ fecundity, offering fresh perspectives for future research into the growth and development of thrips in a laboratory. Our study suggests that experiments involving cut surfaces may be misleading, and further investigations are ongoing to address these concerns. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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13 pages, 3650 KiB

Open AccessArticle

Dung Beetles, Dung Burial, and Plant Growth: Four Scarabaeoid Species and Sorghum

by Hasnae Hajji, Mariyem Rehali, Abdelkhaleq Fouzi Taybi, Jean-Pierre Lumaret and Youness Mabrouki

Insects 2024, 15(12), 1002; https://doi.org/10.3390/insects15121002 - 18 Dec 2024

Viewed by 714

Abstract

This study examined the impact of dung beetles on both sorghum growth and the physico-chemical properties of the soil over a two-month period. Four dung beetle species (Onthophagus vacca, Onthophagus marginalis subsp. andalusicus, Euonthophagus crocatus, and Gymnopleurus sturmi) [...] Read more.

This study examined the impact of dung beetles on both sorghum growth and the physico-chemical properties of the soil over a two-month period. Four dung beetle species (Onthophagus vacca, Onthophagus marginalis subsp. andalusicus, Euonthophagus crocatus, and Gymnopleurus sturmi) were introduced into experimental setups, consisting of containers filled with sterilised clay-loam soil, with three treatment groups: [cow dung + beetles], [cow dung only], and a control group (no dung nor beetles), in order to evaluate their effects on various growth parameters, including the plant height, biomass, leaf area, and chlorophyll concentration. Additionally, changes in soil properties were assessed, focusing on the organic matter content, pH, conductivity, enzyme activities (e.g., urease, phosphatase), and microbial load. The results revealed significant increases in all the measured parameters across the treatments involving dung beetles, emphasising their role in enhancing soil fertility and plant productivity. The study also highlights the variation in effectiveness among the species, suggesting that beetle diversity plays a crucial role in nutrient cycling. Integrating dung beetles into sustainable farming practices could, therefore, serve as a key strategy to promote resilient agriculture. Full article

(This article belongs to the Special Issue Beetles in Integrative Entomology: Biology, Taxonomy, and Conservation)

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20 pages, 4474 KiB

Open AccessArticle

Bacteria Derived from Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), Gut Regurgitant Negatively Regulate Glucose Oxidase-Mediated Anti-Defense Against Host Plant

by Qingxuan Qiao, Huiting Feng, Lu Jiao, Uroosa Zaheer, Chanqin Zheng, Li Zhou, Guifang Lin, Xiujuan Xiang, Huang Liao, Shanyu Li, Haiyan Lu, Anyuan Yin, Yussuf Mohamed Salum, Hui Wei, Wei Chen, Weiyi He and Feiying Yang

Insects 2024, 15(12), 1001; https://doi.org/10.3390/insects15121001 - 17 Dec 2024

Viewed by 649

Abstract

The ongoing interplay among plants, insects, and bacteria underscores the intricate balance of defense mechanisms in ecosystems. Regurgitant bacteria directly/indirectly impact plant immune responses, but the underlying mechanism is unclear. Here, we focus on the interaction between regurgitant bacteria, diamondback moth (DBM), and [...] Read more.

The ongoing interplay among plants, insects, and bacteria underscores the intricate balance of defense mechanisms in ecosystems. Regurgitant bacteria directly/indirectly impact plant immune responses, but the underlying mechanism is unclear. Here, we focus on the interaction between regurgitant bacteria, diamondback moth (DBM), and plant. Six culturable bacteria were isolated from DBM gut regurgitant, including three Enterobacter strains (RB1-3), Micrococcus sp. (RB4), Staphylococcus haemolyticus (RB5), and Bacillus cereus (RB6). These RB strains suppressed genes related to jasmonic acid and glucosinolate signaling pathways but had little effect on salicylic acid signaling pathway genes in Arabidopsis thaliana wounds. RB1 and RB5 inhibited DBM development on A. thaliana but not on an artificial diet. RB1 and RB5 significantly suppressed GOX genes and proteins in DBMs. However, the Pxgox2 insect mutant strain inoculated with RB1 or RB5 did not significantly affect DBM feeding on A. thaliana compared to the wild type. Six RB have been functionally identified, with RB1 and RB5 negatively regulating GOX-mediated host adaptability. The deliberate addition of RB1 and RB5 can negatively affect DBM herbivory and fitness. Our study provides a molecular basis for the further application of RB for insect pest management by modulating insect–plant interactions. Full article

(This article belongs to the Special Issue Effects of Environment and Food Stress on Insect Population)

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19 pages, 3730 KiB

Open AccessArticle

Silencing ACE1 Gene with dsRNA of Different Lengths Impairs Larval Development in Leptinotarsa decemlineata

by Brenda Julian-Chávez, Tania S. Siqueiros-Cendón, Jorge Ariel Torres-Castillo, Sugey Ramona Sinagawa-García, María Jazmín Abraham-Juárez, Carmen Daniela González-Barriga, Quintín Rascón-Cruz, Luis Ignacio Siañez-Estrada, Sigifredo Arévalo-Gallegos and Edward Alexander Espinoza-Sánchez

Insects 2024, 15(12), 1000; https://doi.org/10.3390/insects15121000 - 17 Dec 2024

Viewed by 875

Abstract

In the search for effective strategies to control the Colorado Potato Beetle, RNA interference technology has emerged as a promising method due to its capacity to suppress genes selectively. Factors such as the target gene and double-stranded RNA (dsRNA) length are critical for [...] Read more.

In the search for effective strategies to control the Colorado Potato Beetle, RNA interference technology has emerged as a promising method due to its capacity to suppress genes selectively. Factors such as the target gene and double-stranded RNA (dsRNA) length are critical for optimizing gene silencing efficiency. In this study, we designed and synthesized in vitro dsRNAs of varying lengths targeting the ACE1 gene, which encodes the AChE1 isoform of acetylcholinesterase in the beetle. All tested dsRNA lengths (222 bp, 543 bp, 670 bp, and 870 bp) promoted transcript reduction. The 670 bp dsRNA was the most effective, reducing transcript levels by approximately 40% by day seven, followed by the 543 bp dsRNA. No significant differences were observed between the 222 bp and 870 bp dsRNAs. Furthermore, all of the dsRNA lengths resulted in reduced weight gain and increased mortality in larvae, with the 670 bp dsRNA showing the highest mortality rate, leaving only 63% larval survival, a trend that persisted through day nine. These findings emphasize that dsRNA length is a key factor in the silencing response, underscoring the importance of selecting the optimal length while considering the gene’s target, stability, and delivery methods. This study contributes to establishing design criteria for dsRNA, aiding in the development of more effective and sustainable pest management strategies. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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14 pages, 1176 KiB

Open AccessArticle

The Stress Response of Aphids to the Accumulation of Heavy Metals Along Vicia faba L. Under Cadmium Treatment

by Yexin Xie, Shasha Wang, Sijing Wan, Liya Chen, Qintian Shen, Keting Zhao, Shiyu Tao, Wenjing Zhou, Xinyi Zhang, Xiaoling Tan, Binghua Xie and Bin Tang

Insects 2024, 15(12), 999; https://doi.org/10.3390/insects15120999 - 16 Dec 2024

Viewed by 574

Abstract

Due to the intensification of human activities, the ecosystems are being polluted by heavy metals. The pollution of heavy metals in agricultural systems has become a serious issue of global concern. This study detected the bioaccumulation of cadmium (Cd) in broad beans and [...] Read more.

Due to the intensification of human activities, the ecosystems are being polluted by heavy metals. The pollution of heavy metals in agricultural systems has become a serious issue of global concern. This study detected the bioaccumulation of cadmium (Cd) in broad beans and aphids through continuous exposure to varying concentrations of Cd pollution (0, 3.125, 6.25, 12.5, 25, 50 mg/L) and subsequently examined its effects on aphid energy metabolism and reproductive ability. The results showed that Cd can be transmitted and accumulated between Vicia faba L. and aphids along the food chain, and the amount of accumulation was related to the Cd treatment concentration. Quantitative real-time PCR results showed that the expression levels of trehalase (TRE) and trehalose-6-phosphate synthase (TPS) in F1 were significantly upregulated, and those of vitellogenin (Vg) were varied across the five generations of aphids after Cd treatment, which were up-regulated, and others down-regulated. Compared with the control group, the glycogen content and two types of trehalase activities of the first-generation Cd-treatment aphids were decreased, while trehalose content increased; there was no significant change in the carbohydrate content and trehalase activity of the fourth and fifth generations of aphids. In addition, the reproduction of female aphids was inhibited. This research is helpful for studying the toxic effects of heavy metals on insects and the adaptation mechanisms of insects to extreme environments. It also provides a theoretical basis for further exploring the molecular mechanisms of Cd homeostasis in plants and insects under Cd stress. Full article

(This article belongs to the Special Issue Effects of Environment and Food Stress on Insect Population)

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14 pages, 1860 KiB

Open AccessArticle

Preparation of β-Myrcene-Chitosan Nanoparticles and Their Uptake and Toxicity in Aedes aegypti Larvae

by Lara T. M. Costa, Bruna L. Rocha, Cleidiane C. Teixeira, Hemilly C. Martins, Mauren Cristine A. Silveira, Benedito Albuquerque, Alex Sander R. Cangussu, Peng He, Raimundo Wagner S. Aguiar, Ana Maria S. Maia, Guy Smagghe and Eugênio E. Oliveira

Insects 2024, 15(12), 998; https://doi.org/10.3390/insects15120998 - 16 Dec 2024

Viewed by 854

Abstract

Mosquito control still relies heavily on synthetic molecules, which can lead to the selection of resistant populations and undesirable environmental problems. This study described the preparation of a nanoparticle of the plant-derived molecule, β-myrcene, with chitosan, and the assessment of its toxicity [...] Read more.

Mosquito control still relies heavily on synthetic molecules, which can lead to the selection of resistant populations and undesirable environmental problems. This study described the preparation of a nanoparticle of the plant-derived molecule, β-myrcene, with chitosan, and the assessment of its toxicity against larvae of the yellow fever mosquito, Aedes aegypti. By producing fluorescent chitosan nanoparticles, we were able to observe their distribution in the digestive tract of larvae of Ae. aegypti. Chitosan-based nanoparticles containing β-myrcene (238 mg/L) could kill 100% of the larvae tested, whereas the blank control (i.e., the nanoparticle without β-myrcene) showed no larvicidal activity. The chitosan nanoparticles with β-myrcene had a zeta potential of +15 mV and a hydrodynamic diameter ranging from 30 to 2800 nm. The blank control, without β-myrcene, had a zeta potential of +26 mV and a diameter of 30 to 830 nm. Fluorescence analysis showed that the nanoparticles were efficiently absorbed and distributed in the digestive tract organs of the Ae. aegypti larvae. In short, our results reinforce the benefits of using chitosan to carry molecules of plant-derived-molecules, such as β-myrcene, in mosquito control, suggesting a broad internal distribution that contributes to their toxicity. Full article

(This article belongs to the Section Medical and Livestock Entomology)

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14 pages, 1849 KiB

Open AccessArticle

The Ability to Digest Cellulose Can Significantly Improve the Growth and Development of Silkworms

by Jinxin Wu, Yungui Zhang, Han Chen, Qingyou Xia, Ping Zhao, Ying Lin and Guanwang Shen

Insects 2024, 15(12), 997; https://doi.org/10.3390/insects15120997 - 16 Dec 2024

Viewed by 728

Abstract

Cellulose is essential in the growth and development of herbivores. However, its limited utilization by herbivores is a key factor restricting their feed conversion rates. Cellulase can hydrolyze cellulose into glucose, and the addition of exogenous cellulase preparations to feed is an effective [...] Read more.

Cellulose is essential in the growth and development of herbivores. However, its limited utilization by herbivores is a key factor restricting their feed conversion rates. Cellulase can hydrolyze cellulose into glucose, and the addition of exogenous cellulase preparations to feed is an effective method for improving the cellulose utilization rate of ruminants. Nevertheless, the decomposition efficiency of exogenous cellulase is unstable and susceptible to various external factors. In this study, the endoglucanase III gene from Apriona germari (AgEGase III) was introduced into silkworms to investigate whether transgenic silkworms with cellulose-digesting capabilities outperformed normal silkworms in terms of growth, reproduction, and economic traits. The results show that the transgenic silkworms exhibited increased body size, weight, feeding efficiency, and digestibility compared to the wild-type silkworms. The cocoon weight, shell weight, cocoon–shell ratio, and pupa weight were notably elevated by 11%, 37%, 23%, and 9%, respectively. Additionally, the egg weight and egg-laying quantity of the female moth were also significantly increased compared to those of the wild type. Furthermore, feeding transgenic silkworms with an artificial feed containing additional cellulose demonstrated their ability to digest and utilize cellulose, leading to improved growth and development. This study offers theoretical support for the development of transgenic ruminant species that express cellulolytic enzymes. Full article

(This article belongs to the Section Insect Physiology, Reproduction and Development)

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5 pages, 186 KiB

Open AccessEditorial

Impact of Environmental Factors and Management Practices on Bee Health

by Ivana Tlak Gajger and Franco Mutinelli

Insects 2024, 15(12), 996; https://doi.org/10.3390/insects15120996 - 16 Dec 2024

Viewed by 917

Abstract

The honey bee is a symbol of One Health, a holistic approach to animal, human and environment health, and beekeeping is an economic branch of exceptional importance for public health [...] Full article

(This article belongs to the Special Issue Impact of Environmental Factors and Management Practices on Bee Health)

16 pages, 1540 KiB

Open AccessArticle

The Effect of Cropping Systems on the Dispersal of Mycotoxigenic Fungi by Insects in Pre-Harvest Maize in Kenya

by Ginson M. Riungu, James Muthomi, Maina Wagacha, Wolfgang Buechs, Esther S. Philip and Torsten Meiners

Insects 2024, 15(12), 995; https://doi.org/10.3390/insects15120995 - 16 Dec 2024

Viewed by 787

Abstract

Maize productivity has remained low and has worsened in the wake of a changing climate, resulting in new invasive pests, with pests that were earlier designated as minor becoming major and with pathogens being transported by pests and/or entering their feeding sites. A [...] Read more.

Maize productivity has remained low and has worsened in the wake of a changing climate, resulting in new invasive pests, with pests that were earlier designated as minor becoming major and with pathogens being transported by pests and/or entering their feeding sites. A study was conducted in 2021 in the Kisumu and Makueni counties, Kenya, to determine how different maize cropping systems affect insect diversity, insect damage to maize, and insects’ ability to spread mycotoxigenic fungi in pre-harvest maize. The field experiments used a randomized complete block design, with the four treatments being maize monocrop, maize intercropped with beans, maize–bean intercrop with the addition of Trichoderma harzianum at planting, and push–pull technology. The FAW, Spodoptera frugiperda (J.E Smith) (Lepidoptera: Noctuidae), was the most damaging pest in the two regions. The push–pull and the maize–bean intercropping technologies significantly reduced the maize foliage and ear damage caused by the FAW. Beetles passively spread mycotoxigenic Aspergillus spp. and Fusarium verticillioides on pre-harvest maize. Maize weevils, namely, Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae), and Carpophilus dimidiatus Fabricius, 1792 (Coleoptera: Nitidulidae), earwigs, namely, Forficula spp. L. (Dermaptera: Forficulidae), and carpenter ants, namely, Camponotus spp. L. (Hymenoptera: Formicidae) carried the highest number of spores on their exoskeletons. This study stresses the role of insects in the spread of fungi on pre-harvest maize and their possible control by intercropping and other cropping technologies. Full article

(This article belongs to the Section Insect Pest and Vector Management)

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21 pages, 11953 KiB

Open AccessArticle

Ecological Profile of the Flea Beetle Genus Calotheca Heyden in South Africa (Chrysomelidae, Galerucinae, Alticini)

by Maurizio Biondi, Mattia Iannella and Paola D’Alessandro

Insects 2024, 15(12), 994; https://doi.org/10.3390/insects15120994 - 15 Dec 2024

Viewed by 763

Abstract

In this work, the 25 species of the flea beetle genus Calotheca Heyden recorded for South Africa are considered. Starting from the updated species distribution and the topographic, temperature, and precipitation variables, as well as the vegetation types in the occurrence sites, through [...] Read more.

In this work, the 25 species of the flea beetle genus Calotheca Heyden recorded for South Africa are considered. Starting from the updated species distribution and the topographic, temperature, and precipitation variables, as well as the vegetation types in the occurrence sites, through an analysis of ecological niche modelling, a possible ecological profile is provided, both for each species and the entire genus, highlighting some of the factors that drive their occurrence and distribution patterns. Along with the vegetation type, some climatic variables were found to be particularly influential, such as the mean temperature of both the wettest and driest quarters and also the mean precipitation of the wettest period. Finally, comparing the distribution of the areas of highest suitability returned by the model obtained for Calotheca, they largely overlap with the highest-density areas of Searsia, genus of Anacardiaceae, including the main host plants for these flea beetles. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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18 pages, 4131 KiB

Open AccessArticle

Influence of Floral Strip Width on Spider and Carabid Beetle Communities in Maize Fields

by Jia-Lu Li, Lan-Mei Huang, Zi-Yi Xiang, Jian-Ning Zhao, Dian-Lin Yang, Hui Wang and Yan-Jun Zhang

Insects 2024, 15(12), 993; https://doi.org/10.3390/insects15120993 - 15 Dec 2024

Viewed by 760

Abstract

The study explored the impact of floral strip width on the spider and carabid beetle communities in maize fields over two years. Three widths of floral strips (2 m, 4 m, and 6 m) were compared with maize-only control strips to evaluate species [...] Read more.

The study explored the impact of floral strip width on the spider and carabid beetle communities in maize fields over two years. Three widths of floral strips (2 m, 4 m, and 6 m) were compared with maize-only control strips to evaluate species diversity and distribution. The results showed significant differences in both spider and carabid populations between floral and control strips, with 4 m and 6 m widths consistently harboring higher biodiversity. The results also showed distinct community clustering within floral strips in 2021, which became more cohesive by 2022. Further analysis validated significant community dissimilarities between different strip widths and controls, highlighting the ecological advantages of wider floral strips for enhancing natural enemy biodiversity. Spider activity density was notably higher in floral strips than in adjacent farmland, peaking at the edges of 4 m-wide strips and decreasing in 6 m-wide strips, with the lowest density in 2 m-wide strips. Carabid beetle activity density varied considerably with strip width and proximity to the edge, typically peaking at the edges of wider strips. Spiders were more responsive to strip width than carabid beetles. Based on these findings, we suggest using 4 m- or 6 m-wide floral strips to enhance biodiversity and natural pest control in agricultural landscapes; the floral strips narrower than 4 m (such as 2 m) could not support optimal biodiversity, as spiders and carabid beetles do not disperse far into the maize field, with spiders having dispersal distances of less than 3 m and carabid beetles less than 10 m. Vegetation characteristics significantly influenced spider and carabid communities, impacting species richness, diversity indices, and community structures across two study years. These insights highlight the necessity of thoughtfully designing floral strips to enhance biodiversity and natural pest control in agricultural landscapes. Full article

(This article belongs to the Section Insect Ecology, Diversity and Conservation)

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