Insects

14 pages, 3097 KiB

Open AccessArticle

Breeding Polyommatus icarus Serves as a Large-Scale and Environmentally Friendly Source of Precisely Tuned Photonic Nanoarchitectures

by Gábor Piszter, Zsolt Bálint, Krisztián Kertész, Lajos Szatmári, Gábor Sramkó and László Péter Biró

Insects 2023, 14(8), 716; https://doi.org/10.3390/insects14080716 - 18 Aug 2023

Cited by 5 | Viewed by 1502

Abstract

The colour of the butterfly wing serves as an important sexual and species-specific signal. Some species produce structural colouration by developing wing scales with photonic nanoarchitectures. These nanostructures are highly conservative, allowing only a ±10 nm peak wavelength deviation in the reflectance spectra [...] Read more.

The colour of the butterfly wing serves as an important sexual and species-specific signal. Some species produce structural colouration by developing wing scales with photonic nanoarchitectures. These nanostructures are highly conservative, allowing only a ±10 nm peak wavelength deviation in the reflectance spectra of the blue structural colour in natural Common Blue (Polyommatus icarus) populations. They are promising templates of future artificial photonic materials and can be used in potential applications, too. In this work, we present methodology and infrastructure for breeding laboratory populations of Common Blue as a cost-effective and environmentally friendly source of nanostructures. Our technology enables the production of approximately 7500 wing samples, equivalent to 0.5–1 m² of photonic nanoarchitecture surface within a year in a single custom-made insectarium. To ascertain the reliability of this method, we compared reflectance properties between different populations from distant geographic locations. We also provide genetic background of these populations using microsatellite genotyping. The laboratory population showed genetic erosion, but even after four generations of inbreeding, only minimal shifts in the structural colouration were observed, indicating that wild Common Blue populations may be a reliable source of raw material for photonic surfaces. Full article

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

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10 pages, 884 KiB

Open AccessArticle

A Limiting Factor of Sex Attractants of Bactrocera dorsalis (Diptera: Tephritidae), Verified under Laboratory Conditions

by Qi Chen, Xiaolong Yi, Xiaoyun Wang, Xialin Zheng and Wen Lu

Insects 2023, 14(8), 715; https://doi.org/10.3390/insects14080715 - 18 Aug 2023

Cited by 1 | Viewed by 1325

Abstract

At present, sexual attractants mainly control insect populations by killing males. However, the effect of sex attractants may be limited by the mating ability of the attracted insects. The Oriental fruit fly, Bactrocera dorsalis (Hendel), has a strong reproductive capacity; it brings great [...] Read more.

At present, sexual attractants mainly control insect populations by killing males. However, the effect of sex attractants may be limited by the mating ability of the attracted insects. The Oriental fruit fly, Bactrocera dorsalis (Hendel), has a strong reproductive capacity; it brings great losses to agricultural production, which can be controlled by methods using sex attractant methyl eugenol that mainly attracts males. Therefore, we studied the multiple and continuous (as well as consecutive) mating ability of B. dorsalis through behavioral experiments. The results show that male B. dorsalis can mate 11 times on average, with females mating only 1.93 times, and that 10.81% of males mate more than 20 times. The reproductive capacity of male B. dorsalis decreased significantly after four to five instances of continuous mating. In different mating patterns, the reproductive fitness of polyandry is not the highest, rather, interval mating is the best. A limiting factor of the sex attractant effect was revealed in B. dorsalis through behavioral evidence. Full article

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

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20 pages, 4919 KiB

Open AccessArticle

Evaluation of the Effect of the ENSO Cycle on the Distribution Potential of the Genus Anastrepha of Horticultural Importance in the Neotropics and Panama

by Arturo Batista Degracia, Julián Ávila Jiménez, Anovel Barba Alvarado, Randy Atencio Valdespino and Mariano Altamiranda-Saavedra

Insects 2023, 14(8), 714; https://doi.org/10.3390/insects14080714 - 18 Aug 2023

Cited by 2 | Viewed by 1590

Abstract

Climate variability has made us change our perspective on the study of insect pests and pest insects, focusing on preserving or maintaining efficient production systems in the world economy. The four species of the genus Anastrepha were selected for this study due to [...] Read more.

Climate variability has made us change our perspective on the study of insect pests and pest insects, focusing on preserving or maintaining efficient production systems in the world economy. The four species of the genus Anastrepha were selected for this study due to their colonization and expansion characteristics. Models of the potential distribution of these species are scarce in most neotropical countries, and there is a current and pressing demand to carry out this type of analysis in the face of the common scenarios of climate variability. We analyzed 370 presence records with statistical metrics and 16 bioclimatic variables. The MaxEnt method was used to evaluate the effect of the ENSO cycle on the potential distribution of the species Anastrepha grandis (Macquart), Anastrepha serpetina (Wiedemann), Anastrepha obliqua (Macquart), and Anastrepha striata (Schiner) as imported horticultural pests in the neotropics and Panama. A total of 3472 candidate models were obtained for each species, and the environmental variables with the greatest contribution to the final models were LST range and LST min for A. grandis, PRECIP range and PRECIP min for A. serpentina, LST range and LST min for A. obliqua, and LST min and LST max for A. striata. The percentage expansion of the range of A. grandis in all environmental scenarios was 26.46 and the contraction of the range was 30.80; the percentage expansion of the range of A. serpentina in all environmental scenarios was 3.15 and the contraction of the range was 28.49; the percentage expansion of the range of A. obliqua in all environmental scenarios was 5.71 and the contraction of the range was 3.40; and the percentage expansion of the range of A. striata in all environmental scenarios was 41.08 and the contraction of the range was 7.30, and we selected the best model, resulting in a wide distribution (suitable areas) of these species in the neotropics that was influenced by the variability of climatic events (El Niño, Neutral, and La Niña). Information is provided on the phytosanitary surveillance systems of the countries in areas where these species could be established, which is useful for defining policies and making decisions on integrated management plans according to sustainable agriculture. Full article

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

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15 pages, 2809 KiB

Open AccessEditor’s ChoiceArticle

A New Approach for Detecting Sublethal Effects of Neonicotinoids on Bumblebees Using Optical Sensor Technology

by Vasileia Chatzaki, Marta Montoro, Rámi El-Rashid, Annette Bruun Jensen and Antoine Lecocq

Insects 2023, 14(8), 713; https://doi.org/10.3390/insects14080713 - 17 Aug 2023

Cited by 5 | Viewed by 2056

Abstract

Among insects, bees are important pollinators, providing many vital ecosystem services. The recent pollinator decline is threatening both their diversity and abundance. One of the main drivers of this decline is the extensive use of pesticides. Neonicotinoids, one of the most popular groups [...] Read more.

Among insects, bees are important pollinators, providing many vital ecosystem services. The recent pollinator decline is threatening both their diversity and abundance. One of the main drivers of this decline is the extensive use of pesticides. Neonicotinoids, one of the most popular groups of pesticides, can be toxic to bees. In fact, numerous studies have found that neonicotinoids can cause sublethal effects, which can impair the biology, physiology, and colony survival of the bees. Yet, there are still knowledge gaps, and more research is needed to better understand the interaction between neonicotinoids and bees, especially in the field. A new optical sensor, which can automatically identify flying insects using machine learning, has been created to continuously monitor insect activity in the field. This study investigated the potential use of this sensor as a tool for monitoring the sublethal effects of pesticides on bumblebees. Bombus terrestris workers were orally exposed to field-realistic doses of imidacloprid. Two types of exposures were tested: acute and chronic. The flight activity of pesticide-exposed and non-exposed bumblebees was recorded, and the events of the insect flights recorded by the sensor were used in two ways: to extract the values of the wingbeat frequency and to train machine learning models. The results showed that the trained model was able to recognize differences between the events created by pesticide-exposed bumblebees and the control bumblebees. This study demonstrates the possibility of the optical sensor for use as a tool to monitor bees that have been exposed to sublethal doses of pesticides. The optical sensor can provide data that could be helpful in managing and, ideally, mitigating the decline of pollinators from one of their most major threats, pesticides. Full article

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10 pages, 2538 KiB

Open AccessCommunication

Allometry of Defense: Predator Shift Alters Ontogenetic Growth Patterns in an Antipredator Trait

by Bin Jiang, Yu Yao, Rüdiger Mauersberger and Dirk J. Mikolajewski

Insects 2023, 14(8), 712; https://doi.org/10.3390/insects14080712 - 17 Aug 2023

Cited by 1 | Viewed by 1175

Abstract

Predation is a major factor driving prey trait diversification and promoting ecological speciation. Consequently, antipredator traits are widely studied among prey species. However, comparative studies that examine how different predators shape the ontogenetic growth of antipredator traits are scarce. In larval dragonflies, abdominal [...] Read more.

Predation is a major factor driving prey trait diversification and promoting ecological speciation. Consequently, antipredator traits are widely studied among prey species. However, comparative studies that examine how different predators shape the ontogenetic growth of antipredator traits are scarce. In larval dragonflies, abdominal spines are effective traits against predatory fish in fish lakes, which prefer larger prey. However, defensive spines increase mortality in habitats dominated by invertebrate predators (invertebrate lakes), which prefer smaller prey. Thus, species from fish lakes may accelerate spine growth at a later body size compared to species from invertebrate lakes when growing into the preferred prey size range of predatory fish. In this study, we constructed the allometric relationship between spine length and body size and compared the inflexion point of those growth curves in five species of Leucorrhinia dragonfly larvae. We found that fish-lake Leucorrhinia species accelerated spine growth at a larger body size than congenerics from invertebrate lakes. Further, rather than extending spine length constantly through development, fish-lake species rapidly accelerated spine growth at a larger body size. This is likely to be adaptive for avoiding invertebrate predation at an early life stage, which are also present in fish lakes, though in smaller numbers. Our results highlight that comparative studies of ontogenetic patterns in antipredator traits might be essential to develop an integrated understanding of predator–prey interactions. Full article

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

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13 pages, 2965 KiB

Open AccessReview

The Intricate Role of Ecdysis Triggering Hormone Signaling in Insect Development and Reproductive Regulation

by Pooja Malhotra and Saumik Basu

Insects 2023, 14(8), 711; https://doi.org/10.3390/insects14080711 - 16 Aug 2023

Cited by 4 | Viewed by 3870

Abstract

Insect growth is interrupted by molts, during which the insect develops a new exoskeleton. The exoskeleton confers protection and undergoes shedding between each developmental stage through an evolutionarily conserved and ordered sequence of behaviors, collectively referred to as ecdysis. Ecdysis is triggered by [...] Read more.

Insect growth is interrupted by molts, during which the insect develops a new exoskeleton. The exoskeleton confers protection and undergoes shedding between each developmental stage through an evolutionarily conserved and ordered sequence of behaviors, collectively referred to as ecdysis. Ecdysis is triggered by Ecdysis triggering hormone (ETH) synthesized and secreted from peripheral Inka cells on the tracheal surface and plays a vital role in the orchestration of ecdysis in insects and possibly in other arthropod species. ETH synthesized by Inka cells then binds to ETH receptor (ETHR) present on the peptidergic neurons in the central nervous system (CNS) to facilitate synthesis of various other neuropeptides involved in ecdysis. The mechanism of ETH function on ecdysis has been well investigated in holometabolous insects such as moths Manduca sexta and Bombyx mori, fruit fly Drosophila melanogaster, the yellow fever mosquito Aedes aegypti and beetle Tribolium castaneum etc. In contrast, very little information is available about the role of ETH in sequential and gradual growth and developmental changes associated with ecdysis in hemimetabolous insects. Recent studies have identified ETH precursors and characterized functional and biochemical features of ETH and ETHR in a hemimetabolous insect, desert locust, Schistocerca gregaria. Recently, the role of ETH in Juvenile hormone (JH) mediated courtship short-term memory (STM) retention and long-term courtship memory regulation and retention have also been investigated in adult male Drosophila. Our review provides a novel synthesis of ETH signaling cascades and responses in various insects triggering diverse functions in adults and juvenile insects including their development and reproductive regulation and might allow researchers to develop sustainable pest management strategies by identifying novel compounds and targets. Full article

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

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13 pages, 3415 KiB

Open AccessEditor’s ChoiceArticle

Distribution, Vertical Transmission, and Cooperative Mechanisms of Obligate Symbiotic Bacteria in the Leafhopper Maiestas dorsalis (Hemiptera, Cicadellidea)

by Wei Wu, Jia-Ning Lei, Qianzhuo Mao, Yan-Zhen Tian, Hong-Wei Shan and Jian-Ping Chen

Insects 2023, 14(8), 710; https://doi.org/10.3390/insects14080710 - 14 Aug 2023

Cited by 3 | Viewed by 1530

Abstract

Many insects rely on ancient symbiotic bacterial associations for essential nutrition. Auchenorrhyncha commonly harbor two obligate symbionts: Sulcia (Bacteroidetes) and a proteobacterial partner that supplies essential amino acids lacking in their plant-sap diets. In this study focusing on Maiestas dorsalis, we investigated [...] Read more.

Many insects rely on ancient symbiotic bacterial associations for essential nutrition. Auchenorrhyncha commonly harbor two obligate symbionts: Sulcia (Bacteroidetes) and a proteobacterial partner that supplies essential amino acids lacking in their plant-sap diets. In this study focusing on Maiestas dorsalis, we investigated the distribution and vertical transmission of two obligate symbiotic bacteria, Sulcia and Nasuia, within the leafhopper. Sulcia primarily inhabits the external region of the bacteriome, while Nasuia is restricted to the internal region. Both symbionts progressively infiltrate the ovary through the epithelial plug, ultimately reaching the developing primary oocyte. Furthermore, co-phylogenetic analysis suggests a close correlation between the evolution of Auchenorrhyncha insects and the presence of their obligate symbiotic bacteria. Genomic analysis further unveiled the extreme genome reduction of the obligate symbiotic bacteria, with Sulcia retaining genes involved in basic cellular processes and limited energy synthesis, while Nasuia exhibited further gene loss in replication, transcription, translation, and energy synthesis. However, both symbionts retained the genes for synthesizing the essential amino acids required by the host insect. Our study highlights the coevolutionary dynamics between Sulcia, proteobacterial partners, and their insect hosts, shedding light on the intricate nutritional interactions and evolutionary adaptations in Auchenorrhyncha insects. Full article

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

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16 pages, 3804 KiB

Open AccessArticle

MicroRNA miR-274-5p Suppresses Found-in-Neurons Associated with Melanotic Mass Formation and Developmental Growth in Drosophila

by Hee Kyung Kim, Chae Jeong Kim, Daegyu Jang and Do-Hwan Lim

Insects 2023, 14(8), 709; https://doi.org/10.3390/insects14080709 - 14 Aug 2023

Cited by 1 | Viewed by 1429

Abstract

The hematopoietic system plays a crucial role in immune defense response and normal development, and it is regulated by various factors from other tissues. The dysregulation of hematopoiesis is associated with melanotic mass formation; however, the molecular mechanisms underlying this process are poorly [...] Read more.

The hematopoietic system plays a crucial role in immune defense response and normal development, and it is regulated by various factors from other tissues. The dysregulation of hematopoiesis is associated with melanotic mass formation; however, the molecular mechanisms underlying this process are poorly understood. Here, we observed that the overexpression of miR-274 in the fat body resulted in the formation of melanotic masses. Moreover, abnormal activation of the JNK and JAK/STAT signaling pathways was linked to these consequences. In addition to this defect, miR-274 overexpression in the larval fat body decreased the total tissue size, leading to a reduction in body weight. miR-274-5p was found to directly suppress the expression of found-in-neurons (fne), which encodes an RNA-binding protein. Similar to the effects of miR-274 overexpression, fne depletion led to melanotic mass formation and growth reduction. Collectively, miR-274 plays a regulatory role in the fne–JNK signaling axis in melanotic mass formation and growth control. Full article

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

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17 pages, 1427 KiB

Open AccessArticle

Development of a Diet Production System for Conopomorpha cramerella (Lepidoptera: Gracillariidae), a Major Cocoa Production Pest in Southeast Asia and the Pacific Islands

by Jerome Niogret, Anisah Binti Savantil, Arni Ekayanti, Mavis Peter Jaus, Wulan Wulan, Elviah Mitzo, Jean-Philippe Marelli and Desmond Conlong

Insects 2023, 14(8), 708; https://doi.org/10.3390/insects14080708 - 14 Aug 2023

Viewed by 1516

Abstract

The development of artificial diets for the cocoa pod borer Conopomorpha cramerella, a major pest of cocoa plants, has undergone significant advancements. In this study, we present the success rates of two diet formulations, MM1 and MM4, which have been progressively improved. [...] Read more.

The development of artificial diets for the cocoa pod borer Conopomorpha cramerella, a major pest of cocoa plants, has undergone significant advancements. In this study, we present the success rates of two diet formulations, MM1 and MM4, which have been progressively improved. Nutritional composition analysis revealed that the MM1 diet differed from the natural host, cocoa pods, in several aspects, including protein, carbohydrate, and vitamin C content. To address these differences, modifications were made to the diet compositions, leading to the MM4 diet version. These modifications resulted in improved diet quality and reduced contamination, leading to enhanced success rates in all stages of C. cramerella development. Larval development, pupation success rates, and adult emergence rates were significantly higher in the MM4 diet compared with the MM1 diet. Moreover, the duration of larval development and pupal stage decreased, while adult longevity increased with the MM4 diet. The overall development success of diet-reared insects from egg to adult was comparable with that of insects reared on cocoa pods. However, the cocoon formation, body length and fresh weight of the adults reared on the artificial diets were lower than those reared on cocoa pods. This diet formulation provides a promising approach for laboratory rearing of C. cramerella and opens avenues for further research and mass-rearing initiatives to mitigate the impact of this pest on cocoa production. Full article

(This article belongs to the Special Issue Improved Field Performance of Sterile Male Lepidoptera to Ensure Success in SIT Programmes)

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15 pages, 1918 KiB

Open AccessArticle

Bumble Bees (Bombus terrestris) Use Time-Memory to Associate Reward with Color and Time of Day

by Ozlem Gonulkirmaz-Cancalar, Oded Shertzer and Guy Bloch

Insects 2023, 14(8), 707; https://doi.org/10.3390/insects14080707 - 14 Aug 2023

Cited by 2 | Viewed by 2301

Abstract

Circadian clocks regulate ecologically important complex behaviors in honey bees, but it is not clear whether similar capacities exist in other species of bees. One key behavior influenced by circadian clocks is time-memory, which enables foraging bees to precisely time flower visitation to [...] Read more.

Circadian clocks regulate ecologically important complex behaviors in honey bees, but it is not clear whether similar capacities exist in other species of bees. One key behavior influenced by circadian clocks is time-memory, which enables foraging bees to precisely time flower visitation to periods of maximal pollen or nectar availability and reduces the costs of visiting a non-rewarding flower patch. Bumble bees live in smaller societies and typically forage over shorter distances than honey bees, and it is therefore not clear whether they can similarly associate reward with time of day. We trained individually marked bumble bee (Bombus terrestris) workers to forage for sugar syrup in a flight cage with yellow or blue feeders rewarding either during the morning or evening. After training for over two weeks, we recorded all visitations to colored feeders filled with only water. We performed two experiments, each with a different colony. We found that bees tended to show higher foraging activity during the morning and evening training sessions compared to other times during the day. During the test day, the trained bees were more likely to visit the rewarding rather than the non-rewarding colored feeders at the same time of day during the test sessions, indicating that they associated time of day and color with the sugar syrup reward. These observations lend credence to the hypothesis that bumble bees have efficient time-memory, indicating that this complex behavior is not limited to honey bees that evolved sophisticated social foraging behaviors over large distances. Full article

(This article belongs to the Section Insect Societies and Sociality)

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13 pages, 3794 KiB

Open AccessArticle

Atg2 Regulates Cellular and Humoral Immunity in Drosophila

by Bo Qin, Shichao Yu, Qiming Chen and Li Hua Jin

Insects 2023, 14(8), 706; https://doi.org/10.3390/insects14080706 - 14 Aug 2023

Cited by 2 | Viewed by 1932

Abstract

Autophagy is a process that promotes the lysosomal degradation of cytoplasmic proteins and is highly conserved in eukaryotic organisms. Autophagy maintains homeostasis in organisms and regulates multiple developmental processes, and autophagy disruption is related to human diseases. However, the functional roles of autophagy [...] Read more.

Autophagy is a process that promotes the lysosomal degradation of cytoplasmic proteins and is highly conserved in eukaryotic organisms. Autophagy maintains homeostasis in organisms and regulates multiple developmental processes, and autophagy disruption is related to human diseases. However, the functional roles of autophagy in mediating innate immune responses are largely unknown. In this study, we sought to understand how Atg2, an autophagy-related gene, functions in the innate immunity of Drosophila melanogaster. The results showed that a large number of melanotic nodules were produced upon inhibition of Atg2. In addition, inhibiting Atg2 suppressed the phagocytosis of latex beads, Staphylococcus aureus and Escherichia coli; the proportion of Nimrod C1 (one of the phagocytosis receptors)-positive hemocytes also decreased. Moreover, inhibiting Atg2 altered actin cytoskeleton patterns, showing longer filopodia but with decreased numbers of filopodia. The expression of AMP-encoding genes was altered by inhibiting Atg2. Drosomycin was upregulated, and the transcript levels of Attacin-A, Diptericin and Metchnikowin were decreased. Finally, the above alterations caused by the inhibition of Atg2 prevented flies from resisting invading pathogens, showing that flies with low expression of Atg2 were highly susceptible to Staphylococcus aureus and Erwinia carotovora carotovora 15 infections. In conclusion, Atg2 regulated both cellular and humoral innate immunity in Drosophila. We have identified Atg2 as a crucial regulator in mediating the homeostasis of immunity, which further established the interactions between autophagy and innate immunity. Full article

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

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11 pages, 956 KiB

Open AccessBrief Report

Wide Range of Brachyceran Fly Taxa Attracted to Synthetic and Semi-Synthetic Generic Noctuid Lures and the Description of New Attractants for Sciomyzidae and Heleomyzidae Families

by Antal Nagy, Patrik Katona, Attila Molnár, Zoltán Rádai, Miklós Tóth, Kálmán Szanyi and Szabolcs Szanyi

Insects 2023, 14(8), 705; https://doi.org/10.3390/insects14080705 - 14 Aug 2023

Cited by 1 | Viewed by 1556

Abstract

During field tests implemented in Transcarpathia (West Ukraine) in 2015, 6501 specimens belonging to 26 Brachyceran fly families were collected with traps baited with generic lures (originally developed for noctuid moths) based on fermenting liquid and floral compounds. Isoamyl alcohol-based baits generally attracted [...] Read more.

During field tests implemented in Transcarpathia (West Ukraine) in 2015, 6501 specimens belonging to 26 Brachyceran fly families were collected with traps baited with generic lures (originally developed for noctuid moths) based on fermenting liquid and floral compounds. Isoamyl alcohol-based baits generally attracted more flies than phenylacetaldehyde-based baits and unbaited controls; however, the phenylacetaldehyde-based traps were the most attractive to the Empididae and Milichiidae families. The isoamyl alcohol-based semisynthetic lure showed significant attractivity to the families of Muscidae, Ulidiidae, Sarcophagidae, Calliphoridae, Sciomyzidae, Heleomyzidae, Drosophilidae, Phoridae and Platystomatidae. Additionally, isoamyl alcohol-based semisynthetic lure is the first reported attractant of the Sciomyzidae family. Since our phenylacetaldehyde-based floral lure was also attractive to Heleomyzidae flies, both types of lures can be seen as the first known attractants of this family. Full article

(This article belongs to the Special Issue Chemical Communication in Insects: New Advances in IPM Strategies)

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15 pages, 3143 KiB

Open AccessEditor’s ChoiceArticle

Helmet Shape and Phylogeography of the Treehopper Membracis mexicana

by Marisol De-la-Mora and Daniel Pinero

Insects 2023, 14(8), 704; https://doi.org/10.3390/insects14080704 - 14 Aug 2023

Viewed by 1572

Abstract

Membracis mexicana (Hemiptera: Membracidae) is distributed in four biogeographic provinces of Mexico. Field observations indicate that there are different forms of this species, but the distribution of the phenotype and the genetic variation of this species have not been clarified. The aim of [...] Read more.

Membracis mexicana (Hemiptera: Membracidae) is distributed in four biogeographic provinces of Mexico. Field observations indicate that there are different forms of this species, but the distribution of the phenotype and the genetic variation of this species have not been clarified. The aim of this study was to quantify the phenotypic and genetic variation of M. mexicana and determine whether the configuration of biogeographic provinces impacts the distribution of this variation. To achieve this, we analyzed 307 photographs using 19 landmarks and geometric morphometrics to quantify the phenotypic variation in helmets. We sequenced five molecular markers for 205 individuals to describe the phylogeographic pattern. As a result, we identified three morphological configurations of the helmet of M. mexicana and two genetic lineages. The morphotypes are (1) a large and wide helmet with small dorsal spots, (2) a small and narrow helmet with large dorsal spots, and (3) a small and narrow helmet with small spots. Genetic lineages are distributed in southeast and western Mexico. The western lineage corresponds to two helmet morphotypes (1 and 2) and the southeast lineage to morphotype 3. We found that the larger helmets correspond to the western lineage and are distributed in Trans-Mexican Volcanic Belt and Pacific lowlands provinces, whereas the smallest helmets correspond to the southeast lineage and are present in the Veracruzan and Yucatan Peninsula provinces. Full article

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14 pages, 2259 KiB

Open AccessEditor’s ChoiceArticle

A Rapid Method for Measuring In Vitro Growth in Entomopathogenic Fungi

by Anna R. Slowik, Helen Hesketh, Steven M. Sait and Henrik H. de Fine Licht

Insects 2023, 14(8), 703; https://doi.org/10.3390/insects14080703 - 13 Aug 2023

Cited by 2 | Viewed by 3982

Abstract

Quantifying the growth of entomopathogenic fungi is crucial for understanding their virulence and pathogenic potential. Traditional methods for determining growth, such as biomass determination or colony growth area, are time-consuming and quantitatively and spatially limited in scope. In this study, we introduce a [...] Read more.

Quantifying the growth of entomopathogenic fungi is crucial for understanding their virulence and pathogenic potential. Traditional methods for determining growth, such as biomass determination or colony growth area, are time-consuming and quantitatively and spatially limited in scope. In this study, we introduce a high-throughput method for rapidly measuring fungal growth using spectrophotometry in small-volume, liquid media cultures in 96-well microplates. Optical density (OD) changes were directly correlated with dry weight of samples for six isolates from three species of the genus Metarhizium to validate spectrophotometric growth measurements, and investigate species- and isolate-specific effects. We quantified fungal biomass from the microcultures by extracting, drying, and weighing mycelial mats. From the relationship established between OD and biomass, we generated standard curves for predicting biomass based on the OD values. The OD measurements clearly distinguished growth patterns among six isolates from three Metarhizium species. The logistic growth phase, as captured by the OD measurements, could be accurately assessed within a span of 80 h. Using isolates of M. acridum, M. brunneum, and M. guizhouense, this technique was demonstrated to be an effective, reproducible, and simple method for rapidly measuring filamentous fungal growth with high precision. This technique offers a valuable tool for studying the growth dynamics of entomopathogenic fungi and investigating the factors that influence their growth. Full article

(This article belongs to the Special Issue Insect–Pathogen Interactions in Mass-Reared Insects)

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18 pages, 2466 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Anthropogenic Influence on Moth Populations: A Comparative Study in Southern Sweden

by Markus Franzén, Anders Forsman and Bafraw Karimi

Insects 2023, 14(8), 702; https://doi.org/10.3390/insects14080702 - 11 Aug 2023

Cited by 4 | Viewed by 2132

Abstract

As moths are vital components of ecosystems and serve as important bioindicators, understanding the dynamics of their communities and the factors influencing these dynamics, such as anthropogenic impacts, is crucial to understand the ecological processes. Our study focuses on two provinces in southern [...] Read more.

As moths are vital components of ecosystems and serve as important bioindicators, understanding the dynamics of their communities and the factors influencing these dynamics, such as anthropogenic impacts, is crucial to understand the ecological processes. Our study focuses on two provinces in southern Sweden, Västergötland and Småland, where we used province records from 1974 to 2019 in combination with light traps (in 2020) to record the presence and abundance of moth species, subsequently assessing species traits to determine potential associations with their presence in anthropogenically modified landscapes. This study design provides a unique opportunity to assess temporal changes in moth communities and their responses to shifts in environmental conditions, including anthropogenic impacts. Across the Västergötland and Småland provinces in Sweden, we recorded 776 moth taxa belonging to fourteen different taxonomic families of mainly Macroheterocera. We captured 44% and 28% of the total moth species known from these provinces in our traps in Borås (Västergötland) and Kalmar (Småland), respectively. In 2020, the species richness and abundance were higher in Borås than in Kalmar, while the Shannon and Simpson diversity indices revealed a higher species diversity in Kalmar. Between 1974 and 2019, the colonisation rates of the provinces increased faster in Småland. Ninety-three species were found to have colonised these provinces since 1974, showing that species richness increased over the study period. We reveal significant associations between the probability of a species being present in the traps and distinct traits compared to a provincial species pool. Traits over-represented in the traps included species with a high variation in colour patterns, generalist habitat preferences, extended flight periods, lower host plant specificity, and overwintering primarily as eggs. Our findings underscore the ongoing ecological filtering that favours certain species-specific traits. This study sheds light on the roles of climate change and anthropogenic impacts in shaping moth biodiversity, offers key insights into the ecological processes involved, and can guide future conservation efforts. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects)

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19 pages, 3852 KiB

Open AccessFeature PaperArticle

Transcriptomic Analysis Reveals the Impact of the Biopesticide Metarhizium anisopliae on the Immune System of Major Workers in Solenopsis invicta

by Hongxin Wu, Yating Xu, Junaid Zafar, Surajit De Mandal, Liangjie Lin, Yongyue Lu, Fengliang Jin, Rui Pang and Xiaoxia Xu

Insects 2023, 14(8), 701; https://doi.org/10.3390/insects14080701 - 11 Aug 2023

Viewed by 2061

Abstract

The red imported fire ant (Solenopsis invicta Buren, 1972) is a globally significant invasive species, causing extensive agricultural, human health, and biodiversity damage amounting to billions of dollars worldwide. The pathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin (1883), widely distributed in natural environments, [...] Read more.

The red imported fire ant (Solenopsis invicta Buren, 1972) is a globally significant invasive species, causing extensive agricultural, human health, and biodiversity damage amounting to billions of dollars worldwide. The pathogenic fungus Metarhizium anisopliae (Metchnikoff) Sorokin (1883), widely distributed in natural environments, has been used to control S. invicta populations. However, the interaction between M. anisopliae and the immune system of the social insect S. invicta remains poorly understood. In this study, we employed RNA-seq to investigate the effects of M. anisopliae on the immune systems of S. invicta at different time points (0, 6, 24, and 48 h). A total of 1313 differentially expressed genes (DEGs) were identified and classified into 12 expression profiles using short time-series expression miner (STEM) for analysis. Weighted gene co-expression network analysis (WGCNA) was employed to partition all genes into 21 gene modules. Upon analyzing the statistically significant WGCNA model and conducting Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on the modules, we identified key immune pathways, including the Toll and Imd signaling pathways, lysosomes, autophagy, and phagosomes, which may collectively contribute to S. invicta defense against M. anisopliae infection. Subsequently, we conducted a comprehensive scan of all differentially expressed genes and identified 33 immune-related genes, encompassing various aspects such as recognition, signal transduction, and effector gene expression. Furthermore, by integrating the significant gene modules derived from the WGCNA analysis, we constructed illustrative pathway diagrams depicting the Toll and Imd signaling pathways. Overall, our research findings demonstrated that M. anisopliae suppressed the immune response of S. invicta during the early stages while stimulating its immune response at later stages, making it a potential biopesticide for controlling S. invicta populations. These discoveries lay the foundation for further understanding the immune mechanisms of S. invicta and the molecular mechanisms underlying its response to M. anisopliae. Full article

(This article belongs to the Special Issue Biology, Chemical Ecology and Control of Ants)

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13 pages, 1369 KiB

Open AccessArticle

MicroRNA Expression Prior to Biting in a Vector Mosquito Anticipates Physiological Processes Related to Energy Utilization, Reproduction and Immunity

by Sarah Marzec, Alden Siperstein, Angela Zhou, Christina M. Holzapfel, William E. Bradshaw, Megan E. Meuti and Peter A. Armbruster

Insects 2023, 14(8), 700; https://doi.org/10.3390/insects14080700 - 10 Aug 2023

Cited by 1 | Viewed by 1415

Abstract

Understanding the molecular and physiological processes underlying biting behavior in vector mosquitoes has important implications for developing novel strategies to suppress disease transmission. Here, we conduct small-RNA sequencing and qRT-PCR to identify differentially expressed microRNAs (miRNAs) in the head tissues of two subspecies [...] Read more.

Understanding the molecular and physiological processes underlying biting behavior in vector mosquitoes has important implications for developing novel strategies to suppress disease transmission. Here, we conduct small-RNA sequencing and qRT-PCR to identify differentially expressed microRNAs (miRNAs) in the head tissues of two subspecies of Culex pipiens that differ in biting behavior and the ability to produce eggs without blood feeding. We identified eight differentially expressed miRNAs between biting C. pipiens pipiens (Pipiens) and non-biting C. pipiens molestus (Molestus); six of these miRNAs have validated functions or predicted targets related to energy utilization (miR8-5-p, miR-283, miR-2952-3p, miR-1891), reproduction (miR-1891), and immunity (miR-2934-3p, miR-92a, miR8-5-p). Although miRNAs regulating physiological processes associated with blood feeding have previously been shown to be differentially expressed in response to a blood meal, our results are the first to demonstrate differential miRNA expression in anticipation of a blood meal before blood is actually imbibed. We compare our current miRNA results to three previous studies of differential messenger RNA expression in the head tissues of mosquitoes. Taken together, the combined results consistently show that biting mosquitoes commit to specific physiological processes in anticipation of a blood meal, while non-biting mosquitoes mitigate these anticipatory costs. Full article

(This article belongs to the Special Issue A Commemorative Issue in Appreciation of Professor David L. Denlinger: Great Advances in Insect Physiology)

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13 pages, 6893 KiB

Open AccessArticle

Comparison of Fine Structure of the Compound Eyes in Eucryptorrhynchus scrobiculatus and Eucryptorrhynchus brandti Adults

by Yingying Hao, Qi Wang, Chao Wen and Junbao Wen

Insects 2023, 14(8), 699; https://doi.org/10.3390/insects14080699 - 10 Aug 2023

Cited by 4 | Viewed by 1549

Abstract

Eucryptorrhynchus scrobiculatus and E. brandti are the main borers of Ailanthus altissima, causing serious economic and ecological losses. The external morphology and internal ultrastructure of the compound eyes of two related weevils were investigated with light microscopy, scanning electron microscopy, and transmission [...] Read more.

Eucryptorrhynchus scrobiculatus and E. brandti are the main borers of Ailanthus altissima, causing serious economic and ecological losses. The external morphology and internal ultrastructure of the compound eyes of two related weevils were investigated with light microscopy, scanning electron microscopy, and transmission electron microscopy. E. scrobiculatus and E. brandti possess a pair of reniform apposition compound eyes and contain about 550 ommatidia per eye. The interommatidial angle of E. scrobiculatus and E. brandti are 7.08 ± 0.31° and 4.84 ± 0.49°, respectively. The corneal thickness, rhabdom length, and ommatidium length of E. scrobiculatus are significantly greater than those of E. brandti. Under light-adapted conditions, the pigment granules are mainly distributed at the junction of the cone and the rhabdom, and the diameter and the cross-sectional area of the middle end of the rhabdom is increased in the two weevil species. Under dark-adapted conditions, the pigment granules shift longitudinally and are evenly distributed on both sides of the cone and the rhabdom, and the diameter and cross-sectional area of the middle end of the rhabdom are decreased. The discrepancy in visual structure is beneficial for adaptation to niche differentiation of the two related species. The present results suggest that the two weevils possess different visual organ structures to perceive visual information in the external environment. Full article

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14 pages, 2948 KiB

Open AccessArticle

Enhanced YOLOv5 Object Detection Algorithm for Accurate Detection of Adult Rhynchophorus ferrugineus

by Shuai Wu, Jianping Wang, Li Liu, Danyang Chen, Huimin Lu, Chao Xu, Rui Hao, Zhao Li and Qingxuan Wang

Insects 2023, 14(8), 698; https://doi.org/10.3390/insects14080698 - 9 Aug 2023

Cited by 4 | Viewed by 2233

Abstract

The red palm weevil (RPW, Rhynchophorus ferrugineus) is an invasive and highly destructive pest that poses a serious threat to palm plants. To improve the efficiency of adult RPWs’ management, an enhanced YOLOv5 object detection algorithm based on an attention mechanism is [...] Read more.

The red palm weevil (RPW, Rhynchophorus ferrugineus) is an invasive and highly destructive pest that poses a serious threat to palm plants. To improve the efficiency of adult RPWs’ management, an enhanced YOLOv5 object detection algorithm based on an attention mechanism is proposed in this paper. Firstly, the detection capabilities for small targets are enhanced by adding a convolutional layer to the backbone network of YOLOv5 and forming a quadruple down-sampling layer by splicing and down-sampling the convolutional layers. Secondly, the Squeeze-and-Excitation (SE) attention mechanism and Convolutional Block Attention Module (CBAM) attention mechanism are inserted directly before the SPPF structure to improve the feature extraction capability of the model for targets. Then, 2600 images of RPWs in different scenes and forms are collected and organized for data support. These images are divided into a training set, validation set and test set following a ratio of 7:2:1. Finally, an experiment is conducted, demonstrating that the enhanced YOLOv5 algorithm achieves an average precision of 90.1% ([email protected]) and a precision of 93.8% (P), which is a significant improvement compared with related models. In conclusion, the enhanced model brings a higher detection accuracy and real-time performance to the RPW-controlled pest pre-detection system, which helps us to take timely preventive and control measures to avoid serious pest infestation. It also provides scalability for other pest pre-detection systems; with the corresponding dataset and training, the algorithm can be adapted to the detection tasks of other pests, which in turn brings a wider range of applications in the field of monitoring and control of agricultural pests. Full article

(This article belongs to the Special Issue Palm Ecosystems: Tackling Insect Challenges through Ecology and Conservation Biology, Pest Control and Biotechnology)

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13 pages, 6384 KiB

Open AccessArticle

Novel Lactone-Based Insecticides and Drosophila suzukii Management: Synthesis, Potential Action Mechanisms and Selectivity for Non-Target Parasitoids

by Javier G. Mantilla Afanador, Sabrina H. C. Araujo, Milena G. Teixeira, Dayane T. Lopes, Cristiane I. Cerceau, Felipe Andreazza, Daiana C. Oliveira, Daniel Bernardi, Wellington S. Moura, Raimundo W. S. Aguiar, Ana C. S. S. Oliveira, Gil R. Santos, Elson S. Alvarenga and Eugenio E. Oliveira

Insects 2023, 14(8), 697; https://doi.org/10.3390/insects14080697 - 9 Aug 2023

Cited by 3 | Viewed by 1615

Abstract

Drosophila suzukii, an invasive insect pest, poses a significant threat to various fruit crops. The use of broad-spectrum insecticides to control this pest can reduce the effectiveness of biological control agents, such as the parasitoid Trichopria anastrephae. Here, we evaluated the [...] Read more.

Drosophila suzukii, an invasive insect pest, poses a significant threat to various fruit crops. The use of broad-spectrum insecticides to control this pest can reduce the effectiveness of biological control agents, such as the parasitoid Trichopria anastrephae. Here, we evaluated the toxicity of newly synthesized lactone derivatives on D. suzukii and their selectivity towards T. anastrephae. We used in silico approaches to identify potential targets from the most promising molecules in the D. suzukii nervous system and to understand potential differences in susceptibilities between D. suzukii and its parasitoid. Of the nine molecules tested, (rac)-8 and compound 4 demonstrated efficacy against the fly. Exposure to the estimated LC₉₀ of (rac)-8 and compound 4 resulted in a mortality rate of less than 20% for T. anastrephae without impairing the parasitoid’s functional parasitism. The in silico predictions suggest that (rac)-8 and compound 4 target gamma amino butyric acid (GABA) receptors and transient receptor potential (TRP) channels of D. suzukii. However, only the reduced interaction with TRP channels in T. anastrephae demonstrated a potential reason for the selectivity of these compounds on the parasitoid. Our findings suggest the potential for integrating (rac)-8 and compound 4 into D. suzukii management practices. Full article

(This article belongs to the Special Issue Fly Biology, Ecology, Behavior and Management)

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12 pages, 3219 KiB

Open AccessArticle

First Records of Heartbeats via ECG in a Stingless Bee, Melipona flavolineata (Apidae, Meliponini), during Contention Stress Using Isoflurane as an Anesthetic

by Felipe Andrés León Contrera, Bárbara dos Santos Conceição Lopes, Clarissa Araújo da Paz, Maria Klara Otake Hamoy, Murilo Farias dos Santos, Gabriela Brito Barbosa, Anthony Lucas Gurgel do Amaral, Luiz Henrique Barbosa de Pinho and Moisés Hamoy

Insects 2023, 14(8), 696; https://doi.org/10.3390/insects14080696 - 8 Aug 2023

Cited by 1 | Viewed by 1811

Abstract

The hemodynamic activity of Melipona flavolineata workers was evaluated during restraint stress for a period of 30 min. The observed parameters were power variation in the elapsed time, and subsequently, six periods of one second were divided and called A, B, C, D, [...] Read more.

The hemodynamic activity of Melipona flavolineata workers was evaluated during restraint stress for a period of 30 min. The observed parameters were power variation in the elapsed time, and subsequently, six periods of one second were divided and called A, B, C, D, E and F; in each period, the electrocardiographic parameters were evaluated: spike frequency, amplitude, spike intervals and spike duration. The experiment was carried out with eight worker bees of M. flavolineata, for which electrodes of a nickel–chromium alloy were made. The bees were previously anesthetized with isoflurane and properly contained and fixed in a base for stereotaxis in which the electrode was implanted. All these procedures were performed inside a Faraday cage. The results showed power oscillations during the recording, with the highest energy level being between 300 and 600 s. Spike frequency, spike amplitude, interval between spikes and spike duration parameters underwent changes during the restraint stress period. Thus, the cardiac activity of M. flavolineata can be used as a biomarker and can be used to clarify physiological issues or alterations caused by toxic agents and indicate risk factors for these animals. Full article

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

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14 pages, 2674 KiB

Open AccessArticle

Different Tea Germplasms Distinctly Influence the Adaptability of Toxoptera aurantii (Hemiptera: Aphididae)

by Changhao Lu, Ni Shen, Wenbin Jiang, Bi Xie, Runa Zhao, Guolan Zhou, Degang Zhao, Yingqin He and Wenlong Chen

Insects 2023, 14(8), 695; https://doi.org/10.3390/insects14080695 - 7 Aug 2023

Cited by 4 | Viewed by 1317

Abstract

Aphids are typical phloem-sucking insect pests. A good understanding regarding their feeding behavior and population dynamics are critical for evaluating host adaptation and screening of aphid-resistant resources. Herein, the adaptability of Toxoptera aurantii (Boyer) (Hemiptera: Aphididae) to different hosts was evaluated via electropenetrography [...] Read more.

Aphids are typical phloem-sucking insect pests. A good understanding regarding their feeding behavior and population dynamics are critical for evaluating host adaptation and screening of aphid-resistant resources. Herein, the adaptability of Toxoptera aurantii (Boyer) (Hemiptera: Aphididae) to different hosts was evaluated via electropenetrography and an age-stage, two-sex life table on six tea germplasms: Zikui (ZK), Zhongcha108 (ZC108), Zhongcha111 (ZC111), Qianmei419 (QM419), Meitan5 (MT5), and Fudingdabaicha (FD). Our findings revealed that the feeding activities of T. aurantii differed considerably among the host plants. T. aurantii exhibited significantly more pathway activities on ZK and FD than on the other hosts. However, the duration of feeding of T. aurantii on ZK phloem considerably decreased compared with those of the other germplasms. Life parameters indicated that T. aurantii exhibited the highest intrinsic rate of increase (r), net reproductive rate (R₀), and finite rate of increase (λ) on MT5, and the maximum values of total longevity and oviposition period were recorded on FD; these variables were reduced significantly on ZK. The results of our study demonstrate that T. aurantii can successfully survive on the six tea germplasms; however, ZK was less suitable for T. aurantii and should be considered as a potential source of resistance in breeding and Integrated Pest Management. Full article

(This article belongs to the Special Issue Biology and Molecular Mechanisms of Plant-Aphid Interactions)

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13 pages, 1811 KiB

Open AccessArticle

Coffee Berry Borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae): Activity and Infestation in the High Mountain and Blue Mountain Regions of Jamaica

by Ameka Myrie, Tannice Hall, Denneko Luke, Bhaskar Rao Chinthapalli, Paula Tennant and Dwight Robinson

Insects 2023, 14(8), 694; https://doi.org/10.3390/insects14080694 - 5 Aug 2023

Cited by 3 | Viewed by 1912

Abstract

Jamaica produces coffee marketed as Blue Mountain and high mountain (grown outside the Blue Mountains). Since the discovery of the coffee berry borer (CBB; Hypothenemus hampei) in Jamaica in 1978, chemical control has traditionally been the primary approach used to protect the [...] Read more.

Jamaica produces coffee marketed as Blue Mountain and high mountain (grown outside the Blue Mountains). Since the discovery of the coffee berry borer (CBB; Hypothenemus hampei) in Jamaica in 1978, chemical control has traditionally been the primary approach used to protect the crop from the pest. However, in the last 20 years, there has been an effort to shift towards more sustainable management strategies. The study was conducted to determine CBB activity (trap catch) and field infestation on coffee farms in the high mountains and Blue Mountains of Jamaica, over a crop cycle. A total of 27,929 and 12,921 CBBs were captured at high mountain and Blue Mountain farms, respectively. Peak CBB activity occurred in April in the high mountain region (365 CBBs/trap/month) and February in the Blue Mountain region (129 CBBs/trap/month). The highest levels of infestation were in November (33%) and October (34%) in the high mountain region and Blue Mountain region, respectively. There was no significant difference in the patterns of CBB activity and infestation between the study locations, and neither were related to the temperature or relative humidity. However, there was a significant relationship with rainfall. These data suggest that the population dynamics of the CBB may involve complex interactions among weather conditions, berry development, and agronomic practices. Full article

(This article belongs to the Special Issue Biology, Ecology, and Management of the Coffee Berry Borer (Hypothenemus hampei))

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13 pages, 3746 KiB

Open AccessArticle

Green Manure Crops as Food Source: Impact on the Performance of the Migratory Beet Webworm, Loxostege sticticalis (Lepidoptera: Pyralidae)

by Lin Ma, Yaolu Tang, Lei Zhang and Xingfu Jiang

Insects 2023, 14(8), 693; https://doi.org/10.3390/insects14080693 - 5 Aug 2023

Cited by 1 | Viewed by 1372

Abstract

The application of green manure is crucial for achieving sustainable agriculture and animal husbandry, but pest management is often overlooked. Conducting a risk assessment for insect pests in green manure is essential. The beet webworm, Loxostege sticticalis, a polyphagous insect, is currently [...] Read more.

The application of green manure is crucial for achieving sustainable agriculture and animal husbandry, but pest management is often overlooked. Conducting a risk assessment for insect pests in green manure is essential. The beet webworm, Loxostege sticticalis, a polyphagous insect, is currently experiencing an outbreak in northern China, and represents a significant migratory pest. A two-sex life table and flight mill test approach was used to comprehensively evaluate the effects of three major legume green manure crops (Pisum sativam, Vicia sativa, and Vicia villosa) on the growth, development, fecundity, and flight ability of L. sticticalis in China. Our findings indicate that L. sticticalis cannot utilize V. villosa for generational development. L. sticticalis shows reduced performance on P. sativam and V. sativa compared to its suitable host Chenopodium album. However, both the population parameters (R₀, r, λ, and T) and the population prediction results suggest that L. sticticalis can adapt to P. sativam and V. sativa. In the process of promoting green manure, careful consideration should be given to the selection of appropriate green manure varieties and the implementation of effective pest control measures during their planting. Our findings lay the groundwork for the promotion of green manure and implementation of an ecological management plan for L. sticticalis. Full article

(This article belongs to the Special Issue Recent Advances in Migrant Insect Pests)

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15 pages, 1330 KiB

Open AccessArticle

Local-Scale DNA Barcoding of Afrotropical Hoverflies (Diptera: Syrphidae): A Case Study of the Eastern Free State of South Africa

by Michel Mathurin Kamdem, Mpho Ramoejane and Patricks Voua Otomo

Insects 2023, 14(8), 692; https://doi.org/10.3390/insects14080692 - 4 Aug 2023

Cited by 2 | Viewed by 1288

Abstract

The Afrotropical hoverflies remain an understudied group of hoverflies. One of the reasons for the lack of studies on this group resides in the difficulties to delimit the species using the available identification keys. DNA barcoding has been found useful in such cases [...] Read more.

The Afrotropical hoverflies remain an understudied group of hoverflies. One of the reasons for the lack of studies on this group resides in the difficulties to delimit the species using the available identification keys. DNA barcoding has been found useful in such cases of taxonomical uncertainty. Here, we present a molecular study of hoverfly species from the eastern Free State of South Africa using the mitochondrial cytochrome-c oxidase subunit I gene (COI). The identification of 78 specimens was achieved through three analytical approaches: genetic distances analysis, species delimitation models and phylogenetic reconstructions. In this study, 15 nominal species from nine genera were recorded. Of these species, five had not been previously reported to occur in South Africa, namely, Betasyrphus inflaticornis Bezzi, 1915, Mesembrius strigilatus Bezzi, 1912, Eristalinus tabanoides Jaennicke, 1876, Eristalinus vicarians Bezzi, 1915 and Eristalinus fuscicornis Karsch, 1887. Intra- and interspecific variations were found and were congruent between neighbour-joining and maximum likelihood analyses, except for the genus Allograpta Osten Sacken, 1875, where identification seemed problematic, with a relatively high (1.56%) intraspecific LogDet distance observed in Allograpta nasuta Macquart, 1842. Within the 78 specimens analysed, the assembled species by automatic partitioning (ASAP) estimated the presence of 14–17 species, while the Poisson tree processes based on the MPTP and SPTP models estimated 15 and 16 species. The three models showed similar results (10 species) for the Eristalinae subfamily, while for the Syrphinae subfamily, 5 and 6 species were suggested through MPTP and SPTP, respectively. Our results highlight the necessity of using different species delimitation models in DNA barcoding for species diagnoses. Full article

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

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18 pages, 14282 KiB

Open AccessArticle

Functional Divergence of the Tribolium castaneum engrailed and invected Paralogs

by Summer Blunk, Hector Garcia-Verdugo, Sierra O’Sullivan, James Camp, Michael Haines, Tara Coalter, Terri A. Williams and Lisa M. Nagy

Insects 2023, 14(8), 691; https://doi.org/10.3390/insects14080691 - 4 Aug 2023

Viewed by 1814

Abstract

Engrailed (en) and invected (inv) encode paralogous transcription factors found as a closely linked tandem duplication within holometabolous insects. Drosophila en mutants segment normally, then fail to maintain their segments. Loss of Drosophila inv is viable, while loss of both genes results in asegmental larvae. [...] Read more.

Engrailed (en) and invected (inv) encode paralogous transcription factors found as a closely linked tandem duplication within holometabolous insects. Drosophila en mutants segment normally, then fail to maintain their segments. Loss of Drosophila inv is viable, while loss of both genes results in asegmental larvae. Surprisingly, the knockdown of Oncopeltus inv can result in the loss or fusion of the entire abdomen and en knockdowns in Tribolium show variable degrees of segmental loss. The consequence of losing or knocking down both paralogs on embryogenesis has not been studied beyond Drosophila. To further investigate the relative functions of each paralog and the mechanism behind the segmental loss, Tribolium double and single knockdowns of en and inv were analyzed. The most common cuticular phenotype of the double knockdowns was small, limbless, and open dorsally, with all but a single, segmentally iterated row of bristles. Less severe knockdowns had fused segments and reduced appendages. The Tribolium paralogs appear to act synergistically: the knockdown of either Tribolium gene alone was typically less severe, with all limbs present, whereas the most extreme single knockdowns mimic the most severe double knockdown phenotype. Morphological abnormalities unique to either single gene knockdown were not found. inv expression was not affected in the Tribolium en knockdowns, but hh expression was unexpectedly increased midway through development. Thus, while the segmental expression of en/inv is broadly conserved within insects, the functions of en and inv are evolving independently in different lineages. Full article

(This article belongs to the Special Issue Contributions of Women in Insect Science)

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16 pages, 318 KiB

Open AccessReview

Edible Insects: A Historical and Cultural Perspective on Entomophagy with a Focus on Western Societies

by Marianna Olivadese and Maria Luisa Dindo

Insects 2023, 14(8), 690; https://doi.org/10.3390/insects14080690 - 4 Aug 2023

Cited by 20 | Viewed by 11161

Abstract

The relationship between insects and humans throughout history has always been complex and multifaceted. Insects are both a source of fascination and fear for humans and have played important roles in human culture, economy, and health. Nowadays, there is growing interest in using [...] Read more.

The relationship between insects and humans throughout history has always been complex and multifaceted. Insects are both a source of fascination and fear for humans and have played important roles in human culture, economy, and health. Nowadays, there is growing interest in using insects as a sustainable and environmentally friendly source of protein and other nutrients. Entomophagy can be seen as a new opportunity for the food industry and global food security. In fact, insects require far fewer resources than traditional livestock, and there are many references to insect consumption in human history. The ancient Romans are known to have eaten various insects, including beetles, caterpillars, and locusts. Insects such as crickets, grasshoppers, and ants have been eaten for centuries and are still considered a delicacy in many parts of the world, especially in Africa, Asia, Latin America, and Oceania. Entomophagy has, thus, been a part of human history for thousands of years and continues to be an important food habit for many people around the world. These topics are explored in this article from a historical and cultural perspective (e.g., ecological, nutritional, spiritual, and socio-psychological), with a focus on the progressive acceptance of edible insects in Western societies, since this novel food has also its roots in the Western world. Full article

(This article belongs to the Section Role of Insects in Human Society)

18 pages, 8904 KiB

Open AccessFeature PaperArticle

Poor Air Quality Is Linked to Stress in Honeybees and Can Be Compounded by the Presence of Disease

by Christopher Mayack, Sarah E. Cook, Bernardo D. Niño, Laura Rivera, Elina L. Niño and Arathi Seshadri

Insects 2023, 14(8), 689; https://doi.org/10.3390/insects14080689 - 4 Aug 2023

Cited by 4 | Viewed by 2430

Abstract

Climate change-related extreme weather events have manifested in the western United States as warmer and drier conditions with an increased risk of wildfires. Honeybees, essential for crop pollination in California, are at the center of these extreme weather events. We associated the maximum [...] Read more.

Climate change-related extreme weather events have manifested in the western United States as warmer and drier conditions with an increased risk of wildfires. Honeybees, essential for crop pollination in California, are at the center of these extreme weather events. We associated the maximum daily temperature and air quality index values with the performance of colonies placed in wildfire-prone areas and determined the impact of these abiotic stressors on gene expression and histopathology. Our results indicate that poor air quality was associated with higher maximum daily temperatures and a lower gene expression level of Prophenoloxidase (ProPO), which is tied to immune system strength; however, a higher gene expression level of Vitellogenin (Vg) is tied to oxidative stress. There was a positive relationship between Varroa mites and N. ceranae pathogen loads, and a negative correlation between Varroa mites and Heat Shock Protein 70 (HSP70) gene expression, suggesting the limited ability of mite-infested colonies to buffer against extreme temperatures. Histological analyses did not reveal overt signs of interaction between pathology and abiotic stressors, but N. ceranae infections were evident. Our study provides insights into interactions between abiotic stressors, their relation to common biotic stressors, and the expression of genes related to immunity and oxidative stress in bees. Full article

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11 pages, 1377 KiB

Open AccessArticle

Suppression Trial through an Integrated Vector Management of Aedes albopictus (Skuse) Based on the Sterile Insect Technique in a Non-Isolated Area in Spain

by Carlos Tur, David Almenar, Mario Zacarés, Sandra Benlloch-Navarro, Ignacio Pla and Vicente Dalmau

Insects 2023, 14(8), 688; https://doi.org/10.3390/insects14080688 - 3 Aug 2023

Viewed by 1765

Abstract

In recent years, Aedes albopictus (Skuse, 1984) has expanded its distribution globally due to its high ecological plasticity. This expansion has increased the population’s susceptibility to contracting diseases such as dengue, Zika, and chikungunya, among others, which are transmitted by this mosquito species. [...] Read more.

In recent years, Aedes albopictus (Skuse, 1984) has expanded its distribution globally due to its high ecological plasticity. This expansion has increased the population’s susceptibility to contracting diseases such as dengue, Zika, and chikungunya, among others, which are transmitted by this mosquito species. In the absence of effective control methods, the application of the sterile insect technique (SIT) is proposed as part of an integrated vector management (IVM) program. From 2007 to 2020, this strategy has been tested in a non-isolated mosquito population urban area of 45 ha, representative of the municipalities of the Valencian region (Spain). The population levels of adult females and eggs collected in the traps have been reduced by 70–80% compared to the control area, demonstrating its efficacy in reducing mosquito populations. This work analyzes the impact of the migration of the wild mosquito population from the peri-urban area to the urban core. Full article

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

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14 pages, 10406 KiB

Open AccessArticle

Ultrastructural and Descriptive Study on the Adult Body Surface of Heortia vitessoides (Lepidoptera: Crambidae)

by Lei Liu, Yan Zhang, Shan-Chun Yan, Bin Yang and Gui-Rong Wang

Insects 2023, 14(8), 687; https://doi.org/10.3390/insects14080687 - 3 Aug 2023

Cited by 2 | Viewed by 1593

Abstract

Heortia vitessoides Moore, 1885 (Lepidoptera: Crambidae) is an economically important lepidopteran pest that caused severe damage to the plantation area of Aquilaria sinensis (Lour.) Gilg, 1825 (Thymelaeaceae), resulting in extensive defoliation of the trees during an epidemic. In this study, we used scanning [...] Read more.

Heortia vitessoides Moore, 1885 (Lepidoptera: Crambidae) is an economically important lepidopteran pest that caused severe damage to the plantation area of Aquilaria sinensis (Lour.) Gilg, 1825 (Thymelaeaceae), resulting in extensive defoliation of the trees during an epidemic. In this study, we used scanning electron microscopy (SEM) to analyze the external morphology and ultrastructure of sensilla on various body parts of H. vitessoides. Specifically, seven, four, four, and five types of sensilla were found, respectively, on the antennae, proboscis, labial palps, and legs. We described the types, distributions, and sexual dimorphism of these sensilla on antennae, and found that the number and size of sensilla differed significantly between males and females. This study provides crucial information for future investigations into the function of these sensilla in H. vitessoides. Full article

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