Insects

12 pages, 843 KiB

Open AccessArticle

Insecticidal and Repellent Activity of Plant Powders on the Weevil (Sitophilus zeamais) in Stored Corn Grains in a Rural Community of Oaxaca, Mexico

by Citlaly Peña-Flores, Arturo Zapién-Martínez, Gabriel Sánchez-Cruz, Leobardo Reyes-Velasco, Aristeo Segura-Salvador, Jaime Vargas-Arzola, Luis Alberto Hernández-Osorio, Honorio Torres-Aguilar and Héctor Ulises Bernardino-Hernández

Insects 2025, 16(3), 329; https://doi.org/10.3390/insects16030329 - 20 Mar 2025

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Abstract

The bioinsecticidal and repellent effect of four plant powders (Chenopodium ambrosioides, Piper auritum, Laurus nobilis, and Origanum vulgare) was evaluated in the control of Sitophilus zeamais adults in corn grains stored in the rural community of Santa María [...] Read more.

The bioinsecticidal and repellent effect of four plant powders (Chenopodium ambrosioides, Piper auritum, Laurus nobilis, and Origanum vulgare) was evaluated in the control of Sitophilus zeamais adults in corn grains stored in the rural community of Santa María Zacatepec, Oaxaca, Mexico. Using completely randomized experimental designs, concentrations of 1%, 2%, and 3% by mass of corn grains infested with adults of S. zeamais were tested; the controls were corn without powder and aluminum phosphide. The analysis was performed using ANOVA with Tukey’s post hoc and Student’s t-tests. The highest mortality (>80%) and repellent effect (Repellent Index < 0.3) that were statistically significant were obtained with C. ambrosioides and P. auritum at 3%. Both plant species have the potential for weevil control in stored corn and represent a friendly alternative for the environment and public health in the rural community where the study was conducted. Full article

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

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30 pages, 123003 KiB

Open AccessArticle

Trechus from Ethiopia with Aedeagus Right Side Superior in Repose, an Unusual Character State in Trechine Beetles (Coleoptera: Carabidae)

by Joachim Schmidt, Yeshitla Merene, Yitbarek Woldehawariat and Arnaud Faille

Insects 2025, 16(3), 328; https://doi.org/10.3390/insects16030328 - 20 Mar 2025

Viewed by 291

Abstract

The Miocene volcano Mt. Choke in northern Ethiopia is known for its very species-rich Trechus fauna. In addition, the enormous morphological diversity that is expressed within a single subgenus, Abyssinotus, which is endemic to northern Ethiopia, is unique within the global Trechus [...] Read more.

The Miocene volcano Mt. Choke in northern Ethiopia is known for its very species-rich Trechus fauna. In addition, the enormous morphological diversity that is expressed within a single subgenus, Abyssinotus, which is endemic to northern Ethiopia, is unique within the global Trechus fauna. In this paper, we describe eight additional new species and three subspecies of the Trechus subgenus Abyssinotus, all of which are endemic to Mt. Choke. These species belong to two different lineages within Abyssinotus, each differing from other lineages of the subgenus by certain morphological character states described in this paper and alternatively named the T. lobeliae and the T. basilewskianus subgroups. Several species of these subgroups are characterised by an apomorphical inverse male genital, with the right side up in repose. The T. lobeliae subgroup comprises two species and is monomorphic with respect to this character. The T. basilewskianus subgroup comprises eight species, including six species with monomorphically inverse male genitalia and two species with male genitalia monomorphically in the ‘normal’ position. These are the first examples within Trechinae in which inverse male genitalia are a species- or even group-specific characteristic. A brief summary of the distribution of this trait within the Carabidae is provided. We also present a new identification key for the Trechus species known so far from Mt. Choke. Full article

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

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9 pages, 1409 KiB

Open AccessArticle

Cuticular and Exuvial Biomass and Nitrogen Economy During Assimilation and Growth of the American Grasshopper, Schistocerca americana

by Donald E. Mullins and Sandra E. Gabbert

Insects 2025, 16(3), 327; https://doi.org/10.3390/insects16030327 - 20 Mar 2025

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Abstract

The role of nitrogen metabolism during insect development and reproduction is of primary importance for the success of a species. We conducted a study designed to examine the nitrogen economy of Schistocerca americana from hatching to adulthood, focusing on the processes associated with [...] Read more.

The role of nitrogen metabolism during insect development and reproduction is of primary importance for the success of a species. We conducted a study designed to examine the nitrogen economy of Schistocerca americana from hatching to adulthood, focusing on the processes associated with the assimilation and growth linked to cuticular nitrogen investment, as well as the exuvial nitrogen losses resulting from molting. During development, the grasshopper biomass from the egg stage to the adult stage increased 7-fold for males and 9-fold for females, while their total body nitrogen content increased 23-fold for males and 25-fold for females. During the growth process, the total biomass lost from molting as discarded exuvia was 13% for males and 12% for females. Similarly, the exuvial nitrogen lost during the molting process was 11% for males and 11% for females. Full article

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

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13 pages, 1093 KiB

Open AccessReview

Plasticity in Caste-Fate Determination During the Adult Stage in Temperate Polistes Wasps

by Hideto Yoshimura and Ken Sasaki

Insects 2025, 16(3), 326; https://doi.org/10.3390/insects16030326 - 19 Mar 2025

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Abstract

The reproductive division of labor is a fundamental characteristic of eusociality; thus, understanding the caste determination system underlying the reproductive division of labor would shed more light on the evolution of eusociality. In this review, we summarize the factors associated with caste determination [...] Read more.

The reproductive division of labor is a fundamental characteristic of eusociality; thus, understanding the caste determination system underlying the reproductive division of labor would shed more light on the evolution of eusociality. In this review, we summarize the factors associated with caste determination in temperate Polistes paper wasps and focus on life histories associated with the loss or maintenance of caste plasticity during the adult stage among eusocial Hymenoptera. In many species of eusocial Hymenoptera, caste trajectories are differentiated by nutrition during the larval stages, indicating that caste plasticity is either absent or has not yet been confirmed. However, in temperate Polistes wasps, nutrition during the larval stage only causes biases in caste trajectory, with castes ultimately determined by environmental factors, such as day length and temperature, and colony conditions during the adult stage, indicating high caste plasticity during this stage. Therefore, morphological dimorphism and physiological differences between castes, such as in dopamine levels, have not been found in temperate Polistes wasps at emergence. This plasticity in temperate paper wasps could reflect the fact that females destined to be workers also have a chance to mate with males (especially early males) after emergence, leaving the possibility that they can produce daughters in the emerging year. Full article

(This article belongs to the Section Social Insects and Apiculture)

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15 pages, 1616 KiB

Open AccessArticle

Comparison Between Worker and Soldier Transcriptomes of Termite Neotermes binovatus Reveals Caste Specialization of Host–Flagellate Symbiotic System

by Yu-Hao Huang, Miao Wang, Xiu-Ping Chang, Yun-Ling Ke and Zhi-Qiang Li

Insects 2025, 16(3), 325; https://doi.org/10.3390/insects16030325 - 19 Mar 2025

Viewed by 385

Abstract

Termites are eusocial insects with functionally specialized workers and soldiers, both sharing the same genotype. Additionally, lower termites host flagellates in their hindguts that assist in wood digestion. However, worker-biased and soldier-biased gene expression patterns of the host–flagellate symbiotic system remain underexplored in [...] Read more.

Termites are eusocial insects with functionally specialized workers and soldiers, both sharing the same genotype. Additionally, lower termites host flagellates in their hindguts that assist in wood digestion. However, worker-biased and soldier-biased gene expression patterns of the host–flagellate symbiotic system remain underexplored in most taxonomic groups. In this study, we sequenced high-depth transcriptomes from the workers and soldiers of a lower termite, Neotermes binovatus (Kalotermitidae), to investigate the differentially expressed termite transcripts, flagellate transcript abundance, and co-expression patterns of the host–flagellate transcript pairs in both castes. The worker-biased transcripts were enriched in functions related to cuticle development, nervous system regulation, pheromone biosynthesis, and metabolism, whereas the soldier-biased transcripts were predominantly involved in muscle development and kinesis, body morphogenesis, protein modification, and aggression. Flagellate transcripts from the orders Cristamonadida, Trichomonadida, Tritrichomonadida, and Oxymonadida were identified in both workers and soldiers, with the abundance of most flagellate transcripts tending to be higher in workers than in soldiers. Furthermore, we observed a much larger number of strong co-expression correlations between the termite and flagellate transcripts in workers than in soldiers, suggesting the possibility that soldiers depend more on food processed by worker holobionts than on their own symbiotic system. This research provides insights into the functional specialization of the host–flagellate symbiotic system in the worker and soldier castes of termites, supporting the workers’ roles in nest maintenance, preliminary food processing, and communication, while emphasizing the defensive role of soldiers. Additionally, it offers new perspectives on the potential termite-flagellate interactions and underscores the need for whole-genome data of termite flagellates in further studies. Full article

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

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23 pages, 11199 KiB

Open AccessArticle

Transformation of Internal Thoracic Structures of Callobruchus maculatus (Coleoptera: Bruchidae) from Larva to Adult

by Sipei Liu, Xiaokun Liu, Lijie Zhang, Xieshuang Wang, Xinying Zhang, Le Zong, Wenjie Li, Zhengzhong Huang, Xin Liu and Siqin Ge

Insects 2025, 16(3), 324; https://doi.org/10.3390/insects16030324 - 19 Mar 2025

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Abstract

Callobruchus maculatus is a major quarantine pest of stored legumes in China. As a holometabolous insect, it lives inside the bean it burrows into in both its larval and pupal stages. This study utilized micro-CT and 3D reconstruction to document thoracic morphological transformation [...] Read more.

Callobruchus maculatus is a major quarantine pest of stored legumes in China. As a holometabolous insect, it lives inside the bean it burrows into in both its larval and pupal stages. This study utilized micro-CT and 3D reconstruction to document thoracic morphological transformation during larval and pupal stages. The multi-peak fitting of cranial width was applied to determine larval instars. The results indicate that the first-instar larvae bore into beans using prothoracic muscles and those connecting the head to the mesothorax. The second-instar larva possessed the highest number of thoracic muscles, likely correlating with peak boring activity. The prepupa and the initial pupa exhibited minimal musculature, suggesting larval muscle degradation prior to pupation. Muscles unique to prepupae might homologize with indirect flight muscles in pupae, implying that adult flight capability is determined in the final larval stage. The muscles of both larvae and pupae undergo changes in attachment site, shape and curvature throughout development. At the same time, changes also occur in the larval cuticle and pupal endoskeleton. During the larval stage, muscle growth and degradation occur simultaneously, influencing muscle volume. In the pupal stage, the progressive increase in both absolute and relative thoracic muscle volumes prepare the weevil for movement after emergence. Meanwhile, the other thoracic organs, including the gut, air sacs and nerves, also change during development. Full article

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

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21 pages, 13049 KiB

Open AccessArticle

Population Genetics, Demographic History, and Potential Distributions of the New Important Pests Monolepta signata (Coleoptera: Chrysomelidae) on Corn in China

by Yang Liu, Yacong Ge, Liming Wang, Jingao Dong, Zhenying Wang and Yuyu Wang

Insects 2025, 16(3), 323; https://doi.org/10.3390/insects16030323 - 19 Mar 2025

Viewed by 396

Abstract

Monolepta signata are polyphagous pest widely distributed in China, and the damage as well as economic losses it caused were increasing in recent years. Knowledge of species diversity, population structure and habitat suitability could enhance the efforts of pest control. Here, we sampled [...] Read more.

Monolepta signata are polyphagous pest widely distributed in China, and the damage as well as economic losses it caused were increasing in recent years. Knowledge of species diversity, population structure and habitat suitability could enhance the efforts of pest control. Here, we sampled the populations of M. signata in almost all of China’s major corn-producing regions. A total of 568 sequences were obtained from each gene. There were 48, 29, and 30 haplotypes of COI, ITS2 and EF-1α, respectively. The genetic distance between the HuangHuaiHai population and other populations was the largest. There were 61.90%, 71.43% and 61.90% of Nm values smaller than 1 in COI, ITS2 and EF-1α, respectively, which indicated that gene flow between most populations was weak. The degree of differentiation in most populations of M. signata was relatively high. The population of M. signata has also experienced rapid expansion. Population history dynamic analysis showed that the effective population size of M. signata remained relatively stable before 0.075 Ma. There was a slow contraction trend from 0.075 to 0.010 Ma. It has been rapidly and continuously expanding since 0.010 Ma. Among the investigated geographical populations, the “yellow-spot type” was only present in the populations of southern and southwestern regions, while the “two-spot type” and “four-spot type” were widely distributed in all other geographical populations. Predictions of the potential distribution areas of M. signata indicated that the northeast and north China regions will remain being the high suitability areas of M. signata in the future. Our results will not only facilitate studies on the phylogeography of M. signata but also benefit the effective monitoring and management of this agricultural pest. Full article

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

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15 pages, 5432 KiB

Open AccessArticle

Exploring the Genetic Diversity of the Jewel Beetles Sternocera aequisignata Saunders, 1866, and S. ruficornis Saunders, 1866 (Coleoptera: Buprestidae) in Thailand and Lao PDR

by Anisanee Thaenasa, Nakorn Pradit, Warayutt Pilap, Chavanut Jaroenchaiwattanachote, Komgrit Wongpakam, Khamla Inkhavilay, Jatupon Saijuntha, Wittaya Tawong, Warong Suksavate, Chairat Tantrawatpan and Weerachai Saijuntha

Insects 2025, 16(3), 322; https://doi.org/10.3390/insects16030322 - 19 Mar 2025

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Abstract

Jewel beetles of the genus Sternocera are widely distributed across tropical regions, including Thailand and Lao PDR, where the green-legged S. aequisignata Saunders, 1866, and red-legged S. ruficornis Saunders, 1866, are commonly found. These jewel beetles have significant economic importance, as they are [...] Read more.

Jewel beetles of the genus Sternocera are widely distributed across tropical regions, including Thailand and Lao PDR, where the green-legged S. aequisignata Saunders, 1866, and red-legged S. ruficornis Saunders, 1866, are commonly found. These jewel beetles have significant economic importance, as they are edible, and their iridescent wings are used to create jewelry, leading to high market demand and intensive harvesting. Additionally, their habitats are being rapidly destroyed, resulting in population decline. However, genetic information on these species remains limited. This study aims to investigate the genetic diversity of S. aequisignata and S. ruficornis from various localities in Thailand and Lao PDR using mitochondrial cytochrome c oxidase subunit 1 (CO1) and 16S ribosomal DNA (16S rDNA) sequences. High genetic diversity was observed, with 45 and 62 CO1 haplotypes and 35 and 28 16S rDNA haplotypes identified in S. aequisignata and S. ruficornis populations, respectively. Haplotype network and phylogenetic analyses clearly distinguish S. aequisignata from S. ruficornis. Based on CO1 sequences, S. aequisignata was divided into three distinct haplogroups (GG1–GG3). Haplogroup GG1 was the most widespread, occurring in both Thailand and Lao PDR, while haplogroups GG2 and GG3 were restricted to some localities in northern, western, and northeastern Thailand, as well as Lao PDR. These findings suggest the presence of cryptic diversity within S. aequisignata, with at least three genetically distinct groups. Further comprehensive studies on the biology, ecology, and genetic diversity of these jewel beetles across their distribution range are essential to better understand their evolutionary dynamics. Full article

(This article belongs to the Special Issue Genetic Diversity of Insects)

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31 pages, 39485 KiB

Open AccessArticle

Subfossil Insects of the Kebezen Site (Altai Mountains): New Data on the Last Deglaciation Environment

by Anna A. Gurina, Natalia I. Agrikolyanskaya, Roman Yu. Dudko, Yuri E. Mikhailov, Alexander A. Prokin, Sergei V. Reshetnikov, Alexey S. Sazhnev, Alexey Yu. Solodovnikov, Evgenii V. Zinovyev and Andrei A. Legalov

Insects 2025, 16(3), 321; https://doi.org/10.3390/insects16030321 - 19 Mar 2025

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Abstract

This paper focuses on insect remains found at the Kebezen site (51.93600° N, 87.09665° E) on the Turachak stream, Altai Republic, Russia, in layers ranging in age from 20.1 to 19.3 cal ky BP, corresponding to the onset of the last deglaciation. Coleoptera, [...] Read more.

This paper focuses on insect remains found at the Kebezen site (51.93600° N, 87.09665° E) on the Turachak stream, Altai Republic, Russia, in layers ranging in age from 20.1 to 19.3 cal ky BP, corresponding to the onset of the last deglaciation. Coleoptera, represented by 105 species from 21 families, predominate in the sediments, with the families Carabidae, Staphylinidae, Chrysomelidae and Scolytidae being the most numerous. The insect assemblage of Kebezen contrasts sharply with the Late Pleistocene entomofauna of the West Siberian Plain, but it is similar with the assemblages of the geographically close Lebed site (Oldest and Older Dryas). Also, it corresponds well with the modern middle-altitude entomofauna of the mountains of north-eastern Altai. Based on such entomological data, boreal forests with a predominance of Picea and alpine meadows, as well as a cold and humid climate, were reconstructed for the Kebezen site. Changes in the ecological composition of beetles were traced during sedimentation: the most complete spectrum of the basal layer was replaced by a complex with a significant predominance of meadow and water-edge species, after which the proportions of shrub species, bryophilous species, and forest species consistently increased. Such changes correspond to the course of primary succession initiated by a catastrophic factor such as a megaflood. Full article

(This article belongs to the Special Issue Fossil Insects: Diversity and Evolutionary History)

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24 pages, 4805 KiB

Open AccessArticle

A Computational Analysis Based on Automatic Digitization of Movement Tracks Reveals the Altered Diurnal Behavior of the Western Flower Thrips, Frankliniella occidentalis, Suppressed in PKG Expression

by Chunlei Xia, Gahyeon Jin, Falguni Khan, Hye-Won Kim, Yong-Hyeok Jang, Nam Jung, Yonggyun Kim and Tae-Soo Chon

Insects 2025, 16(3), 320; https://doi.org/10.3390/insects16030320 - 19 Mar 2025

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Abstract

The western flower thrips, Frankliniella occidentalis, a worldwide insect pest with its polyphagous feeding behavior and capacity to transmit viruses, follows a diurnal rhythmicity driven by expression of the circadian clock genes. However, it remained unclear how the clock signal triggers the [...] Read more.

The western flower thrips, Frankliniella occidentalis, a worldwide insect pest with its polyphagous feeding behavior and capacity to transmit viruses, follows a diurnal rhythmicity driven by expression of the circadian clock genes. However, it remained unclear how the clock signal triggers the thrips behaviors. This study posed a hypothesis that the clock signal modulates cGMP-dependent protein kinase (PKG) activity to mediate the diurnal behaviors. A PKG gene is encoded in F. occidentalis and exhibits high sequence homologies with those of honeybee and fruit fly. Interestingly, its expression followed a diel pattern with high expression during photophase in larvae and adults of F. occidentalis. It is noteworthy that PKG expression was clearly observed in the midgut during photophase but not in scotophase from our fluorescence in situ hybridization analysis. A prediction of protein–protein interaction suggested its functional association with clock genes. To test this functional link, RNA interference (RNAi) of the PKG gene expression was performed by feeding a gene-specific double-stranded RNA, which led to significant alteration of the two clock genes (Clock and Period) in their expression levels. The RNAi treatment caused adverse effects on early-life development and adult fecundity. To further analyze the role of PKG in affecting diurnal behavior, the adult females were continuously observed for a 24 h period with an automatic digitization device to obtain movement parameters and durations (%) in different micro-areas in the observation arena. Diel difference was observed with speed in RNAi-control females at 0.16 mm/s and 0.08 mm/s, in photo- and scotophase, respectively, whereas diel difference was not observed for the PKG-specific RNAi-treated females, which showed 0.07 mm/s and 0.06 mm/s, respectively. The diel difference was also observed in durations (%) in the control females, more strongly in the intermediate area in the observation arena. Speed and durations in the different micro-areas in mid-scotophase were significantly different from most photophase in the control females, while speed was significantly different mainly during late photophase when comparing effects of control and RNAi treatments in each light phase. Three sequential stages consisting of high activity followed by feeding and visiting of micro-areas were observed for the control females. For RNAi-treated females, the three phases were disturbed with irregular speed and visits to micro-areas. These results suggest that PKG is associated with implementing the diurnal behavior of F. occidentalis by interacting with expressions of the circadian clock genes. Full article

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

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14 pages, 2835 KiB

Open AccessArticle

Marigold, Tagetes patula, a Trap Plant for Western Flower Thrips, Frankliniella occidentalis, in Ornamental Bedding Plants Under Controlled Greenhouse Conditions

by Cheryl Frank Sullivan, Bruce L. Parker and Margaret Skinner

Insects 2025, 16(3), 319; https://doi.org/10.3390/insects16030319 - 19 Mar 2025

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Abstract

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) [Thysanoptera: Thripidae], is a destructive pest of greenhouse ornamentals. Flowering yellow marigolds, Tagetes patula (L.) [Asterales: Asteraceae], have been shown to be attractive to WFT, implicating their suitability as a trap plant. However, functionality may vary [...] Read more.

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) [Thysanoptera: Thripidae], is a destructive pest of greenhouse ornamentals. Flowering yellow marigolds, Tagetes patula (L.) [Asterales: Asteraceae], have been shown to be attractive to WFT, implicating their suitability as a trap plant. However, functionality may vary in part due to crop variety, the growth stage of the crop in which the marigold trap plant is deployed and whether or not the crop plants have flowers present. The attractiveness of yellow marigolds was tested within several varieties of mature, flowering ornamental bedding plants that were flowering or had their flowers removed: Calibrachoa spp. Petunia spp. Verbena spp., Osteospermum spp., Impatiens haekeri and other marigolds. Trials were conducted in cages under controlled greenhouse conditions for six weeks. The effectiveness of orange vs. yellow marigolds as a trap plant was also assessed. The results showed that WFT were attracted to flowering marigolds and, over time, were present in greater numbers on these than crop plants for all crop species and varieties tested at varying levels of significance. Yellow marigold trap plants were the least effective when deployed within other marigold varieties. In crops with flowers, it took up to five weeks for the number of WFT on trap plants to surpass numbers on crop plants. In contrast, in crop varieties with their flowers removed, trap plants attracted WFT earlier, within one to two weeks, and harbored them in greater numbers over time. Orange, flowering marigolds were a less effective trap plant compared to yellow marigolds. These results confirm that flowering yellow marigolds are attractive to WFT and have potential as a trap plant in greenhouse ornamentals, particularly when crop plants do not have flowers. Full article

(This article belongs to the Special Issue Insects Vectors of Phytopathogenic Agents: Biology, Host-Plant Interactions, and Management)

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13 pages, 1345 KiB

Open AccessArticle

trans-α-Necrodyl Acetate: Minor Sex Pheromone Component of the Invasive Mealybug Delottococcus aberiae (De Lotto)

by Javier Marzo Bargues, Sandra Vacas, Ismael Navarro Fuertes, Daniel López-Puertollano, Jaime Primo, Antonio Abad-Somovilla and Vicente Navarro-Llopis

Insects 2025, 16(3), 318; https://doi.org/10.3390/insects16030318 - 19 Mar 2025

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Abstract

Reported in Europe in the early 2000s, Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is an invasive mealybug pest that is causing severe damage to citrus production in eastern Spain. Once its main sex pheromone component was identified in a previous work as (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl [...] Read more.

Reported in Europe in the early 2000s, Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is an invasive mealybug pest that is causing severe damage to citrus production in eastern Spain. Once its main sex pheromone component was identified in a previous work as (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate 1, the revision of virgin female effluvia is here reported to improve knowledge about the biology of D. aberiae. A new minor component has been identified in the volatile samples collected from virgin females as ((1R, 4R)-3,4,5,5-tetramethylcyclopent-2-en-1-yl)methyl acetate (trans-α-necrodyl acetate, (1R, 4R)-2), a compound also found in the essential oil of Lavandula stoechas subsp. luisieri. Bioassay testing of the activity of this compound showed that a synthetic sample of the racemate (±)-(trans)-2 was attractive to D. aberiae males both in the laboratory and field but with a lower attractant power than enantiopure (1R, 4R)-2 and (±)-(1). The 1:1 mixture of (1R, 4R)-2 and (±)-1 provided a slight additive effect. Further trials are needed to know the pest control potential of this minor compound but the possibility of obtaining this substance from a natural source could pose an important advantage to implement new methods for the sustainable control of D. aberiae. Full article

(This article belongs to the Special Issue Inter- and Intra-specific Interactions by Semiochemicals in Arthropods)

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18 pages, 2573 KiB

Open AccessArticle

In Silico Analysis of Potential Off-Target Effects of a Next-Generation dsRNA Acaricide for Varroa Mites (Varroa destructor) and Lack of Effect on a Bee-Associated Arthropod

by Mariana Bulgarella, Aiden Reason, James W. Baty, Rose A. McGruddy, Eric R. L. Gordon, Upendra K. Devisetty and Philip J. Lester

Insects 2025, 16(3), 317; https://doi.org/10.3390/insects16030317 - 19 Mar 2025

Viewed by 505

Abstract

Double-stranded RNA (dsRNA) biopesticides offer the potential for highly targeted pest control with minimal off-target impacts. Varroa mites (Varroa destructor) are an important pest of honey bees (Apis mellifera) that are primarily managed by synthetic pesticides. A next-generation treatment [...] Read more.

Double-stranded RNA (dsRNA) biopesticides offer the potential for highly targeted pest control with minimal off-target impacts. Varroa mites (Varroa destructor) are an important pest of honey bees (Apis mellifera) that are primarily managed by synthetic pesticides. A next-generation treatment using a varroa-active dsRNA, vadescana, has been developed to target calmodulin expression in varroa. We evaluated the potential exposure of non-target species to vadescana. First, we assessed potential gene silencing effects on 39 arthropods with known genomes via bioinformatics. Three mite species, monarch butterflies (Danaus plexippus), fruit flies (Drosophila melanogaster), and European earwigs (Forficula auricularia) showed theoretical potential for off-target effects. These in silico results could be used to help inform risk assessments. Second, we conducted vadescana feeding trials on the greater wax moth (Galleria mellonella), a common beehive associate. There were no significant differences in wax moth reproduction, survival, or adult F2 wing length between vadescana-fed and control groups. Male F2 body weight was slightly but significantly lower in wax moths exposed to the highest vadescana dose, with no such effect observed in female moths. Calmodulin gene expression was unaffected in wax moths. Our hazard assessment of vadescana’s lethal and sublethal effects on wax moths indicates minimal impact following continuous dietary exposure far greater than any exposure that might be expected in the field, in line with the bioinformatics findings. This biopesticide appears highly varroa-specific and likely has fewer non-target effects than many current varroa control methods. Full article

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

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20 pages, 12053 KiB

Open AccessArticle

Integrated mRNA and miRNA Omics Analyses Reveal Transcriptional Regulation of the Tolerance Traits by Aquatica leii in Response to High Temperature

by Chao Liu, Jiapeng Li, Lihong Yan, Yuting Zhu, Zikun Li, Chengquan Cao and Yiping Wang

Insects 2025, 16(3), 316; https://doi.org/10.3390/insects16030316 - 18 Mar 2025

Viewed by 329

Abstract

Within the context of global warming, understanding the molecular mechanisms behind physiological plasticity and local adaptation is essential for insect populations. This study performed an integrated miRNA and mRNA analysis on Aquatica leii larvae exposed to temperatures of 20 °C, 24 °C, 28 [...] Read more.

Within the context of global warming, understanding the molecular mechanisms behind physiological plasticity and local adaptation is essential for insect populations. This study performed an integrated miRNA and mRNA analysis on Aquatica leii larvae exposed to temperatures of 20 °C, 24 °C, 28 °C, and 32 °C. Under varying thermal conditions, 1983 genes exhibited differential expression (i.e., DEGs). These genes showed significant enrichment in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to carbohydrate metabolism, glycan biosynthesis and metabolism. Notably, we detected that the “neuroactive ligand–receptor interaction” signaling pathway, which is involved in environmental information processing, was significantly upregulated in the 28 °C and 32 °C treatment groups. This indicates that starting at 28 °C, A. leii needs to maintain normal cellular physiological functions by regulating ligand–receptor binding and signal transduction. Furthermore, 220 differentially expressed miRNAs (DEMs) were detected under the different temperature treatment conditions. An interaction network was constructed between key DEMs and DEGs, revealing 12 significant DEM-DEG regulatory pairs in A. leii under different temperature treatments. We found three miRNA-mRNA candidate modules that could be involved in A. leii’s response to high temperature, including ggo-miR-1260b and ptr-miR-1260b/RN001_010114, CM069438.1_43851/RN001_014852, and CM069438.1_43851/RN001_014877. Our data provide deeper insights into the molecular responses of A. leii to the high temperature at the miRNA and mRNA levels. Full article

(This article belongs to the Special Issue Aquatic Insects: Ecology, Diversity and Conservation)

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11 pages, 1273 KiB

Open AccessArticle

Screening the Resistance of Male Aedes aegypti and Anopheles coluzzii to Insecticides in the Context of Using Genetic Control Tools in Burkina Faso

by Hamidou Maiga, Abel Souro Millogo, Koama Bayili, Etienne Bilgo, Inoussa Toe, Roch Kounbobr Dabiré, Jeremy Bouyer and Abdoulaye Diabaté

Insects 2025, 16(3), 315; https://doi.org/10.3390/insects16030315 - 18 Mar 2025

Viewed by 336

Abstract

Background: Genetic control tools, such as the sterile insect technique (SIT) and genetically modified mosquitoes (GMMs), require releasing males comparable to their wild counterparts. Ensuring that released males do not exhibit higher insecticide resistance is critical. This study assessed the phenotypic characteristics and [...] Read more.

Background: Genetic control tools, such as the sterile insect technique (SIT) and genetically modified mosquitoes (GMMs), require releasing males comparable to their wild counterparts. Ensuring that released males do not exhibit higher insecticide resistance is critical. This study assessed the phenotypic characteristics and insecticide susceptibility of key dengue and malaria vector species. Methods: Phenotypic resistance to deltamethrin (0.05%) was tested in two-to-five-day-old male and female Aedes aegypti (Linnaeus, 1762) (Borabora and Bobo strains) and Anopheles coluzzii (Coetzee & Wilkerson, 2013) (Vallee du Kou strain) using WHO susceptibility guidelines. Wing measurements of live and dead mosquitoes were used to assess body size. Results: Mortality rates were similar between male and female Ae. aegypti (Bobo strain) and An. coluzzii, while Ae. aegypti Borabora was fully susceptible in both sexes. Females were consistently larger than males, with significantly larger live females than dead ones in the Ae. aegypti Bobo strain. Conclusion: This study highlights sex-specific differences in body size and insecticide susceptibility. Integrating these analyses into vector management programs is essential for the success and sustainability of SIT- and GMM-based interventions targeting malaria and dengue vectors. Implications for integrating genetic control strategies are discussed. Full article

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

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17 pages, 2416 KiB

Open AccessArticle

The First Cavernicolous Species of Arrhopalites (Collembola, Symphypleona, Arrhopalitidae) from China and Its Phylogenetic Position

by Nerivania Nunes Godeiro, Yun Bu, Gleyce da Silva Medeiros, Yan Gao and Robert S. Vargovitsh

Insects 2025, 16(3), 314; https://doi.org/10.3390/insects16030314 - 18 Mar 2025

Viewed by 285

Abstract

Arrhopalites Börner, 1906 includes 40 valid species, with 20 considered troglobionts, exclusive to caves. Arrhopalites beijingensis sp. nov. is the third species from China and the first from a cave habitat, collected in the Xianrendong Cave, Beijing, Junzhuang Town. It resembles several species [...] Read more.

Arrhopalites Börner, 1906 includes 40 valid species, with 20 considered troglobionts, exclusive to caves. Arrhopalites beijingensis sp. nov. is the third species from China and the first from a cave habitat, collected in the Xianrendong Cave, Beijing, Junzhuang Town. It resembles several species of the Caecus group, possessing spine-like chaetae on the head, five to seven subsegments on Ant IV with annulated separations, and lacking cuticular spines on Abd VI; it differs from these species in its various characteristics. The mitogenome of A. beijingensis sp. nov. was assembled (14,774 bp in length), marking the first made available from the genus. Due to the incipient number of published mitochondrial genomes of Symphypleona, we downloaded raw sequencing data and performed the assemblies and annotations of 11 species. Our phylogenetic analyses comprised 24 mitogenomes in total; of those, 22 were of Symphypleona and 2 were of outgroups. A. beijingensis sp. nov. was placed closer to Pygmarrhopalites spinosus (Rusek, 1967), with high support. Arrhopalitidae was found as a sister group to Katiannidae, both part of Katiannoidea. The two species of Sminthuridida were placed as a sister group to all other Appendiciphora. More systematic analyses and enhanced sampling from key lineages are needed to better understand Symphypleona’s internal relationships and evolution. Full article

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

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24 pages, 427 KiB

Open AccessReview

Ecology of Ahasverus advena in Stored Products and Other Habitats

by David W. Hagstrum and Bhadriraju Subramanyam

Insects 2025, 16(3), 313; https://doi.org/10.3390/insects16030313 - 18 Mar 2025

Viewed by 342

Abstract

The foreign grain beetle, Ahasverus advena (Waltl) (Coleoptera: Silvanidae), has been reported from 110 countries on more than 162 commodities, more than 35 types of facilities, and 14 other habitats such as compost heaps and haystacks or manure. Compost heaps, haystacks, and manure [...] Read more.

The foreign grain beetle, Ahasverus advena (Waltl) (Coleoptera: Silvanidae), has been reported from 110 countries on more than 162 commodities, more than 35 types of facilities, and 14 other habitats such as compost heaps and haystacks or manure. Compost heaps, haystacks, and manure heated by fermentation may allow overwintering in cold climates, making them important sources of infestation. From these sources the A. advena can fly and infest grain storage and processing facilities. A. advena has been found in empty grain storage bins, is often found in wheat immediately after harvest, and is most abundant early in wheat storage. Larvae and adults of A. advena are well adapted to feeding on several species of fungi and have higher chitinase levels and greater tolerance for fungal aflatoxins than other species. A. advena lay more eggs on the fungal species on which their offspring can develop most successfully. They are attracted to fungal odors and high moisture commodities and have the capability to disseminate grain fungi that cause hot spots within the grain mass. The presence of fungus beetles is indicative of poor storage conditions. A. advena is capable of feeding on some commodities and is a predator that may have a potential role in biological control. They are strong fliers but are distributed extensively with the movement of commodities in the marketing system. In countries with a zero tolerance for insects, their presence is sufficient for rejection of a load and associated economic losses. In other countries, contamination by A. advena is a problem, and in India, it is listed as a quarantine pest. Extension agents have had many requests for the identification of this species, and two other species of the same genus have been found in stored products. Some information is available for the effectiveness of nine pest management methods for A. advena. Full article

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

14 pages, 1919 KiB

Open AccessArticle

Temporal and Spatial Patterns of Mating in Rhodnius prolixus

by Franco Divito, Gabriel A. De Simone, Lorena Pompilio and Gabriel Manrique

Insects 2025, 16(3), 312; https://doi.org/10.3390/insects16030312 - 18 Mar 2025

Viewed by 343

Abstract

The kissing bug Rhodnius prolixus is a nocturnal species; however, its temporal mating patterns remain unexplored. Copulation lasts about fifty minutes, during which time the couple remains almost motionless. We hypothesized that R. prolixus copulates within shelters to reduce its vulnerability. To test [...] Read more.

The kissing bug Rhodnius prolixus is a nocturnal species; however, its temporal mating patterns remain unexplored. Copulation lasts about fifty minutes, during which time the couple remains almost motionless. We hypothesized that R. prolixus copulates within shelters to reduce its vulnerability. To test this, we examined the spatial and temporal patterns of its copulation, as well as the potential endogenous regulation of its circadian rhythm, under three conditions: a light:dark cycle (L/D), constant light (L/L), and constant darkness (D/D). Over ten days, the number and the timing of copulation of pairs in arenas containing a shelter were video-recorded. Under the L/D cycle, the pairs mated mainly during daylight hours. This rhythm persisted under the D/D cycle, with a peak extending from the first half of the subjective day to the first half of the subjective night. No rhythm was observed under the L/L cycle. A greater proportion of mating occurred within the shelters during the L/D and L/L cycles, whereas its spatial distribution was random under the D/D cycle. Our results reveal an endogenously controlled circadian rhythm of mating behavior, with mating activity mainly occurring during daylight hours. Additionally, we showed that the pairs copulated inside the shelters. These results provide new insights into the reproductive behavior of R. prolixus. Full article

(This article belongs to the Special Issue Arthropod Reproductive Biology)

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24 pages, 1315 KiB

Open AccessReview

How Insects Balance Reproductive Output and Immune Investment

by Jimena Leyria, Leonardo L. Fruttero, Pedro A. Paglione and Lilián E. Canavoso

Insects 2025, 16(3), 311; https://doi.org/10.3390/insects16030311 - 17 Mar 2025

Viewed by 1498

Abstract

Insects face the constant challenge of balancing energy allocation between reproduction and immune responses, both of which are highly energy-demanding processes. Immune challenges frequently result in decreased fecundity, reduced egg viability, and delayed ovarian development. Conversely, heightened reproductive activity often suppresses immune functions. [...] Read more.

Insects face the constant challenge of balancing energy allocation between reproduction and immune responses, both of which are highly energy-demanding processes. Immune challenges frequently result in decreased fecundity, reduced egg viability, and delayed ovarian development. Conversely, heightened reproductive activity often suppresses immune functions. This trade-off has profound ecological and evolutionary consequences, shaping insects’ survival, adaptation, and population dynamics. The intricate interplay between reproduction and immunity in insects is regulated by the neuroendocrine and endocrine systems, which orchestrate resource distribution alongside other biological processes. Key hormones, such as juvenile hormone and ecdysteroids, serve as central regulators, influencing both immune responses and reproductive activities. Additionally, macromolecules like vitellogenin and lipophorin, primarily known for their functions as yolk protein precursors and lipid carriers, play crucial roles in pathogen recognition and transgenerational immune priming. Advancements in molecular and omics tools have unveiled the complexity of these regulatory mechanisms, providing new insights into how insects dynamically allocate resources to optimize their fitness. This delicate balance underscores critical evolutionary strategies and the integration of physiological systems across species. This review synthesizes insights from life history theory, oogenesis, and immunity, offering new perspectives on the trade-offs between reproductive output and immune investment. Full article

(This article belongs to the Special Issue Arthropod Reproductive Biology)

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14 pages, 1919 KiB

Open AccessArticle

Temperature Effects on the Survival and Oviposition of an Invasive Blow Fly Chrysomya rufifacies Macquart (Diptera: Calliphoridae)

by Travis W. Rusch, Samantha J. Sawyer, Abigail E. Orr, Nicholas Richter, David Sohn, Lauren Gagner, Alexandria Smith, Jeffery K. Tomberlin and Aaron M. Tarone

Insects 2025, 16(3), 310; https://doi.org/10.3390/insects16030310 - 17 Mar 2025

Viewed by 390

Abstract

The globally increased severity and frequency of elevated temperatures are altering native species’ geographic distributions and local abundances while also increasing the invasion of new areas by exotic species. These distributional shifts have affected native species. Through two experiments, we investigated the effects [...] Read more.

The globally increased severity and frequency of elevated temperatures are altering native species’ geographic distributions and local abundances while also increasing the invasion of new areas by exotic species. These distributional shifts have affected native species. Through two experiments, we investigated the effects of temperature on the survival and oviposition of the hairy maggot blow fly Chrysomya rufifacies (Macquart), a highly competitive and predatory invasive blow fly of ecological, economic, and forensic importance. In our first experiment, we exposed mixed-sex colonies of C. rufifacies to a given temperature (10–45.0 °C) for 24 h. High survival (≥90%) was observed from 10 to 40 °C, with moderate mortality at 42.5 °C (29.2%) and high mortality at 43.5 °C (75.4%). All flies died when exposed to 44.5 or 45.0 °C for 24 h. Oviposition occurred from 22.5 to 42.5 °C, with the greatest occurrences (100%) at 30 and 35 °C and the greatest number of eggs (2035) occurring at 30 °C. Although oviposition occurred from 22.5 to 42.5 °C, egg viability was only observed from 22.5 to 37.5 °C. Thus, C. rufifacies has distinct thermal limits for survival, and oviposition may exhibit a bet-hedging strategy in response to temperature exposure. In our second experiment, we assessed the effects of an acute heat shock on C. rufifacies oviposition performance. Adult virgins (males and females) were exposed to 25.0 °C, 42.0 °C, or 44.0 °C for 1 h, and then maintained at ~25 °C in mixed-sex colonies for 14 d. Pre-breeding heat exposure had no effect on male or female reproductive success, except for females exposed to 44.0 °C. Females exposed to this temperature before breeding oviposited sooner (2.5 ± 0.0 d, 37.5% decrease), more frequently (0.5 ± 0.4, 33.3% increase), and produced more eggs (10,772.9 ± 2258.6 eggs, 73.3% increase) than female flies exposed to 25 °C. The combined results show that C. rufifacies survives exposures up to 43.5 °C, successfully oviposits up to 37.5 °C, and accelerates both oviposition timing and intensity following brief exposure to near upper lethal temperatures (44.0 °C), potentially provides C. rufifacies a competitive advantage over native calliphorids in warming environments. Full article

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

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29 pages, 6044 KiB

Open AccessArticle

Collembola from the Gypsum Karst of Sorbas (Almería, Spain), with Descriptions of Three New Species

by Enrique Baquero, Pablo Barranco and Rafael Jordana

Insects 2025, 16(3), 309; https://doi.org/10.3390/insects16030309 - 16 Mar 2025

Viewed by 543

Abstract

The gypsum karst of Sorbas (Almería, Spain) is home to a diverse community of Collembola. Over seven years of sampling, 7875 specimens were collected from 83 cave visits, representing four orders: Symphypleona (5251 specimens), Entomobryomorpha (2552), Poduromorpha (32), and Neelipleona (29). A total [...] Read more.

The gypsum karst of Sorbas (Almería, Spain) is home to a diverse community of Collembola. Over seven years of sampling, 7875 specimens were collected from 83 cave visits, representing four orders: Symphypleona (5251 specimens), Entomobryomorpha (2552), Poduromorpha (32), and Neelipleona (29). A total of 25 species were identified. The most abundant are listed in descending order of abundance: Pygmarrhopalites ruizporteroae sp. nov., Pseudosinella najtae, Pygmarrhopalites subbifidus, Troglopedetes machadoi, Pseudosinella sexocellata sp. nov., Pygmarrhopalites torresi sp. nov., and Heteromurus major. Additionally, partial redescriptions of Pseudosinella najtae and Troglopedetes machadoi are provided. This research enhances the taxonomic framework of subterranean Collembola and provides new insights into species differentiation and adaptation. The methodologies applied allow for high-resolution morphological characterization, essential for species delimitation. The results highlight the potential for further discoveries in gypsum caves and emphasize the need for advanced imaging techniques in Collembola taxonomy. Full article

(This article belongs to the Section Other Arthropods and General Topics)

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17 pages, 1487 KiB

Open AccessArticle

The Role of Parental and Institutional Approaches in the Persistence of Pediculosis Capitis in Early Childhood Education Settings: A General Survey

by Marzena Kotus, Aleksandra Sędzikowska, Joanna Kulisz, Zbigniew Zając, Agnieszka Borzęcka-Sapko, Aneta Woźniak, Andrzej Tytuła and Katarzyna Bartosik

Insects 2025, 16(3), 308; https://doi.org/10.3390/insects16030308 - 16 Mar 2025

Viewed by 486

Abstract

Pediculus humanus capitis infestation is one of the most underestimated parasitoses still constituting a current epidemiological and social problem. Haematophagous insects, the etiological factor of pediculosis capitis, spread most easily in preschool children, which is determined by social and behavioural aspects. The study [...] Read more.

Pediculus humanus capitis infestation is one of the most underestimated parasitoses still constituting a current epidemiological and social problem. Haematophagous insects, the etiological factor of pediculosis capitis, spread most easily in preschool children, which is determined by social and behavioural aspects. The study aimed to search for factors contributing to pediculosis capitis persistence in kindergartens located in south-eastern Poland. For this purpose, anonymous surveys among the management staff of preschool institutions were conducted. Head lice infestations were reported in 87.0% of the 561 surveyed facilities. A positive correlation was confirmed between the prevalence of head lice and a higher number of children in these facilities. Additionally, in 69.3% of the facilities where cases of pediculosis capitis were reported, it was noted that the infestation was associated with the child’s attendance at preschool. Familial and occupational transmission was observed in 78.5% and 25.2% of the facilities, respectively. In contrast, in 93.2% of preschools where no cases of infestation were reported, all parents consented to periodic head inspections. Parents’ attitudes and their perception of head lice as a health issue, rather than an embarrassing problem, appear to be key factors in effectively limiting the spread of head lice in the studied kindergartens. Full article

(This article belongs to the Collection Humans and Arthropod Bites and Stings: Venom and Envenomation)

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11 pages, 1929 KiB

Open AccessArticle

Field Evaluation of Synthetic Components of the Sex Pheromone of the Tea Pest Helopeltis cinchonae Mann (Hemiptera: Miridae)

by Fida Hussain Magsi, David R. Hall, Zongxiu Luo, Xiangfei Meng, Chunli Xiu, Zhaoqun Li, Lei Bian, Nanxia Fu, Jianlong Li, Zongmao Chen and Xiaoming Cai

Insects 2025, 16(3), 307; https://doi.org/10.3390/insects16030307 - 16 Mar 2025

Viewed by 418

Abstract

Helopeltis cinchonae is an emerging pest of tea and causes severe damage to tea plantations in China. The female of H. cinchonae has been reported to produce a sex pheromone consisting of two components, hexyl (3R)-3-acetoxybutyrate and (5R)-1-acetoxy-5-butyroxyhexane, and [...] Read more.

Helopeltis cinchonae is an emerging pest of tea and causes severe damage to tea plantations in China. The female of H. cinchonae has been reported to produce a sex pheromone consisting of two components, hexyl (3R)-3-acetoxybutyrate and (5R)-1-acetoxy-5-butyroxyhexane, and lures containing the synthetic compounds have been shown to attract male H. cinchonae to traps in the field. This is the first time that components of the sex pheromone have been identified for a species of Helopeltis bug, but their field application has not been evaluated in detail. The present study shows that a blend of both compounds loaded into a polyethylene vial at 0.2 and 2 mg, respectively, caught significantly more male H. cinchonae bugs than the individual compounds and all the other tested blends. Sticky wing traps baited with the binary blend of compounds at the optimized ratio and dosage caught more bugs than bucket funnel or delta traps, and traps hung at a height of 10 cm above the tea shoots caught more bugs than those at other heights. The optimized traps and lures were used for monitoring the pest and two distinct population peaks of H. cinchonae were observed, the first one during mid-May to early June, and the other one in mid-September. Overall, the results of this study contribute to an environmentally-friendly approach to monitoring and managing H. cinchonae in the field. Full article

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

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14 pages, 2961 KiB

Open AccessArticle

Cadmium Contaminants in Pollen and Nectar Are Variably Linked to the Growth and Foraging Behaviors of Honey Bees

by Dawei Li, Jia Liu, Yibin Yuan, Juanli Chen and Junpeng Mu

Insects 2025, 16(3), 306; https://doi.org/10.3390/insects16030306 - 15 Mar 2025

Viewed by 615

Abstract

Cadmium (Cd) is a heavy metal present in pollen and nectar that affects pollinator attributes. Honey bees possess the ability to eliminate Cd from honey. Consequently, the concentration of Cd in pollen, rather than nectar, is the critical factor influencing the growth and [...] Read more.

Cadmium (Cd) is a heavy metal present in pollen and nectar that affects pollinator attributes. Honey bees possess the ability to eliminate Cd from honey. Consequently, the concentration of Cd in pollen, rather than nectar, is the critical factor influencing the growth and foraging behavior of honey bees. However, there is a dearth of studies regarding the specific association by which the impact on bee growth and foraging behavior fluctuates in relation to the Cd dosage of pollen or nectar. We hypothesized that at low exposure levels, the amount of Cd in pollen would affect honey bee growth, and the amount of nectar influences honey bee foraging behavior. At high exposure levels, the amount of Cd in pollen and nectar would affect both honey bee growth and foraging behavior. A field experiment was performed in Sichuan (the average background value of Cd in soil is 5.6 times higher than other regions in China) to examine the impact of different soil Cd concentrations (low: 0.60 ± 0.05 mg·kg⁻¹ (average ± SD); middle: 1.32 ± 0.08 mg·kg⁻¹; high: 1.76 ± 0.10 mg·kg⁻¹) on the Cd levels in plant organs (Brassica campestris), alongside the body mass and visitation rates of honey bees (Apis mellifera). Our results indicated in honey bees in the habitats with low concentrations of soil Cd that the Cd content in pollen was inversely correlated with the body mass of larvae, pupae, and worker bees. The quantity of nectar governed the foraging activity of honey bees in the habitats with low levels of soil Cd. At middle to high exposure levels, Cd concentrations in pollen and honey exerted a negative influence on honey bee development and foraging behavior. These findings offer novel insights into the impact of Cd on pollinator attributes, and the global decline of pollinators. Full article

(This article belongs to the Special Issue Bee Conservation: Behavior, Health and Pollination Ecology)

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31 pages, 19158 KiB

Open AccessArticle

Faunal and Ecological Analysis of Gamasid Mites (Acari: Mesostigmata) Associated with Small Mammals in Yunnan Province, Southwest China

by Peng-Wu Yin, Pei-Ying Peng, Xian-Guo Guo, Wen-Yu Song, Tian-Guang Ren, Ya-Fei Zhao, Wen-Ge Dong and Dao-Chao Jin

Insects 2025, 16(3), 305; https://doi.org/10.3390/insects16030305 - 15 Mar 2025

Viewed by 438

Abstract

Gamasid mites (Acari: Mesostigmata) are ecologically diverse arthropods, many of which act as vectors for zoonotic diseases such as rickettsial pox and hemorrhagic fever with renal syndrome. This study investigates the faunal and ecological patterns of gamasid mites across five zoogeographic microregions in [...] Read more.

Gamasid mites (Acari: Mesostigmata) are ecologically diverse arthropods, many of which act as vectors for zoonotic diseases such as rickettsial pox and hemorrhagic fever with renal syndrome. This study investigates the faunal and ecological patterns of gamasid mites across five zoogeographic microregions in Yunnan Province, China, a biodiversity hotspot with complex topography. From 1990 to 2022, 18,063 small mammal hosts (primarily rodents) were surveyed, yielding 167 mite species (141,501 specimens). The key findings include the following: (1) Low host specificity: most mite species parasitized >10 host species, with Laelaps nuttalli, L. echidninus, Dipolaelaps anourosorecis, L. guizhouensis, L. turkestanicus, and L. chini dominating (>76.59% abundance). (2) Environmental heterogeneity: mountainous and outdoor habitats exhibited higher mite diversity than flatland/indoor environments. (3) Zoonotic risks: thirteen vector species with low host specificity were identified, potentially amplifying disease transmission. (4) Ecological niche dynamics: high niche overlaps (e.g., Laelaps guizhouensis vs. L. xingyiensis: O_ik = 0.997) and positive interspecific correlations (e.g., L. echidninus vs. L. nuttalli: R = 0.97, p < 0.01) suggest co-occurrence trends on shared hosts. (5) Biogeographic patterns: mite communities were clustered distinctly by microregion, with the highest similarity being obtained between western/southern plateaus (IV and V) and unique diversity in the Hengduan Mountains (I). (6) Chao 1 estimation predicted 203 total mite species in Yunnan, 36 of which were undetected in the current sampling. These results highlight the interplay of biogeography, host ecology, and environmental factors in shaping mite distributions, with implications for zoonotic disease surveillance in biodiverse regions. Full article

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

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11 pages, 3209 KiB

Open AccessBrief Report

Functional Investigation of the Receptor to the Major Pheromone Component in the C-Strain and the R-Strain of the Fall Armyworm Spodoptera frugiperda

by Arthur Comte, Alizée Delarue, Marie-Christine François, Christelle Monsempes, Camille Meslin, Nicolas Montagné and Emmanuelle Jacquin-Joly

Insects 2025, 16(3), 304; https://doi.org/10.3390/insects16030304 - 14 Mar 2025

Viewed by 423

Abstract

The fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important invasive polyphagous crop pest that has been invading the world since 2016. This species consists of two strains adapted to different host plants, the corn strain and the rice strain, which also exhibit [...] Read more.

The fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important invasive polyphagous crop pest that has been invading the world since 2016. This species consists of two strains adapted to different host plants, the corn strain and the rice strain, which also exhibit differences in their mating behavior, pheromone composition, and pheromone receptor sequences. A way to monitor invasion and control this pest is the use of synthetic sex pheromones to trap adults and disturb the mate-finding process via the release of large amounts of pheromones in the air. However, the efficiency of these methods depends on the specificity and sensitivity of the corresponding pheromone receptors. Yet, only pheromone receptors of the corn strain have been characterized, and nothing is known about the specificity and sensitivity of the rice strain orthologues. To address this gap, we functionally expressed the receptors to the major sex pheromone component of the two strains in Drosophila olfactory sensory neurons and challenged them with a large panel of pheromone compounds using single-sensillum recordings. Although their sequences present subtle mutations, we revealed that they share similar response spectra and sensitivity. The implications of these results on pheromone-based pest management strategies are discussed. Full article

(This article belongs to the Special Issue Inter- and Intra-specific Interactions by Semiochemicals in Arthropods)

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19 pages, 8397 KiB

Open AccessArticle

Risk Assessment of Effects of Essential Oils on Honey Bees (Apis mellifera L.)

by Joel Caren, Yu-Cheng Zhu, Quentin D. Read and Yuzhe Du

Insects 2025, 16(3), 303; https://doi.org/10.3390/insects16030303 - 14 Mar 2025

Viewed by 574

Abstract

The toxicity of synthetic pesticides to non-target organisms has prompted a shift towards more environmentally friendly agricultural pest control methods, including the use of essential oils as possible biopesticides. Before these natural chemicals can be widely adopted for protecting food supplies and human [...] Read more.

The toxicity of synthetic pesticides to non-target organisms has prompted a shift towards more environmentally friendly agricultural pest control methods, including the use of essential oils as possible biopesticides. Before these natural chemicals can be widely adopted for protecting food supplies and human health, it is crucial to evaluate their impacts on pollinators, such as honey bees. In this study, we examined the effects of one commercially available essential oil mixture (EcoTec+) and four essential oil components (β-bisabolene, cinnamaldehyde, 1,8-cineole, and eugenol) on honey bee workers using feeding or spray treatment. We then assessed the responses of esterase (EST), glutathione-S-transferase (GST), acetylcholine esterase (AChE), and P450. EcoTec+ increased the P450 transcript, while bisabolene inhibited EST and AChE, increased GST, and caused a mixed P450 response without being lethal. Cinnamaldehyde exhibited toxicity when ingested, suppressing P450 and eliciting a mixed response in AChE. Cineole inhibited EST but caused a mixed P450 response. Eugenol suppressed EST and AChE and was toxic on contact. We also assayed combinations of each compound with four synthetic formulations representative of the major pesticide categories, though no significant interactions were found. Overall, the essential oils tested did not cause acute lethal toxicity to honey bees; however, their biochemical effects varied, mostly remaining sublethal. These findings suggest that these essential oils could be considered safe for use around honey bees. Full article

(This article belongs to the Section Social Insects and Apiculture)

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14 pages, 10114 KiB

Open AccessArticle

A New Species Amecephala micra sp. nov. (Hemiptera: Liadopsyllidae) from Mid-Cretaceous Myanmar Amber

by Jowita Drohojowska, Marina Hakim, Diying Huang and Jacek Szwedo

Insects 2025, 16(3), 302; https://doi.org/10.3390/insects16030302 - 13 Mar 2025

Viewed by 650

Abstract

The new species Amecephala micra sp. nov. is described and illustrated on the basis of a well-preserved male psyllid (Liadopsyllidae) in a piece of Cretaceous Myanmar amber. This second species of the genus Amecephala Drohojowska, Szwedo, Müller et Burckhardt, 2020 exhibits a combination [...] Read more.

The new species Amecephala micra sp. nov. is described and illustrated on the basis of a well-preserved male psyllid (Liadopsyllidae) in a piece of Cretaceous Myanmar amber. This second species of the genus Amecephala Drohojowska, Szwedo, Müller et Burckhardt, 2020 exhibits a combination of features that have not been previously recognised among Liadopsyllidae. These features include details of the antennae, hind legs and their armature, and hind wings. The presence of a short apical spine on the apex of the metatibia suggests that it was likely capable of jumping, and the strengthening of the claval margin of the hind wing may be interpreted as part of the apparatus for vibrational communication. These issues are discussed in relation to modern Psylloidea and Liadopsyllidae. The finding offers an important contribution to knowledge of the disparity and taxonomic diversity of Liadopsyllidae and their evolutionary traits. Full article

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

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31 pages, 35205 KiB

Open AccessArticle

New Species of the Purse-Web Spider Genus Atypus Latreille, 1804 from Southern China (Araneae, Atypidae), with the General Natural History of Atypus Spiders

by Yecheng Wu, Yang Liu, Zongguang Huang, Haiqiang Yin and Xiang Xu

Insects 2025, 16(3), 301; https://doi.org/10.3390/insects16030301 - 13 Mar 2025

Viewed by 428

Abstract

Three species of the purse-web spider genus Atypus Latreille, 1804, collected from Hunan and Sichuan Provinces of China, are diagnosed and described as new to science: A. yaozu sp. nov. (♂♀), A. siyiensis sp. nov. (♂♀) and A. yanjingensis sp. nov. (♂♀). Detailed [...] Read more.

Three species of the purse-web spider genus Atypus Latreille, 1804, collected from Hunan and Sichuan Provinces of China, are diagnosed and described as new to science: A. yaozu sp. nov. (♂♀), A. siyiensis sp. nov. (♂♀) and A. yanjingensis sp. nov. (♂♀). Detailed descriptions, photographs and DNA barcodes of the three new species and a distribution map of Atypus species in China are provided. Additionally, we enrich the general natural history of the genus Atypus through a decade of observation. Full article

(This article belongs to the Topic Arthropod Biodiversity: Ecological and Functional Aspects, 2nd Edition)

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21 pages, 3037 KiB

Open AccessArticle

Remodeling of Cellular Respiration and Insulin Signaling Are Part of a Shared Stress Response in Divergent Bee Species

by Nicole C. Rondeau, Joanna Raup-Collado, Helen V. Kogan, Rachel Cho, Natalie Lovinger, Fatoumata Wague, Allison J. Lopatkin, Noelle G. Texeira, Melissa E. Flores, David Rovnyak and Jonathan W. Snow

Insects 2025, 16(3), 300; https://doi.org/10.3390/insects16030300 - 13 Mar 2025

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Abstract

The honey bee (Apis mellifera) is of paramount importance to human activities through the pollination services they provide in agricultural settings. Honey bee colonies in the United States have suffered from an increased rate of annual die-off in recent years, stemming [...] Read more.

The honey bee (Apis mellifera) is of paramount importance to human activities through the pollination services they provide in agricultural settings. Honey bee colonies in the United States have suffered from an increased rate of annual die-off in recent years, stemming from a complex set of interacting stressors that remain poorly described. Defining the cellular responses that are perturbed by divergent stressors represents a key step in understanding these synergies. We found that multiple model stressors induce upregulated expression of the lactate dehydrogenase (Ldh) gene in the midgut of the eusocial honey bee and that the Ldh gene family is expanded in diverse bee species. Alterations in Ldh expression were concomitant with changes in the expression of other genes involved in cellular respiration and genes encoding insulin/insulin-like growth factor signaling (IIS) pathway components. Additionally, changes in metabolites in the midgut after stress, including increased levels of lactate, linked metabolic changes with the observed changes in gene expression. Select transcriptional changes in response to stress were similarly observed in the solitary alfalfa leafcutting bee (Megachile rotundata). Thus, increased Ldh expression may be part of a core stress response remodeling cellular respiration and insulin signaling. These findings suggest that a conserved cellular response that regulates metabolic demands under diverse stressful conditions may play a protective role in bees regardless of life history. Full article

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

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Insects, Volume 16, Issue 3 (March 2025) – 97 articles

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