Insects

13 pages, 4882 KiB

Open AccessArticle

Newly Emerging Pest in China, Rhynchaenusmaculosus (Coleoptera: Curculionidae): Morphology and Molecular Identification with DNA Barcoding

by Rui-Sheng Yang, Ming-Yang Ni, Yu-Jian Gu, Jia-Sheng Xu, Ying Jin, Ji-Hui Zhang, Yong Wang and Li Qin

Insects 2021, 12(6), 568; https://doi.org/10.3390/insects12060568 - 21 Jun 2021

Cited by 2 | Viewed by 2593

Abstract

The oak flea weevil, Rhynchaenusmaculosus Yang et Zhang 1991, is a newly emerging pest that severely damages oak (genus Quercus) in China. The first R. maculosus outbreak occurred in 2020 and caused spectacular damage to all oak forests in Jilin province, [...] Read more.

The oak flea weevil, Rhynchaenusmaculosus Yang et Zhang 1991, is a newly emerging pest that severely damages oak (genus Quercus) in China. The first R. maculosus outbreak occurred in 2020 and caused spectacular damage to all oak forests in Jilin province, northeast China. The lack of key morphological characters complicates the identification of this native pest, especially in larva and pupa stages. This is problematic because quick and accurate species identification is crucial for early monitoring and intervention during outbreaks. Here, we provided the first detailed morphological description of R. maculosus at four life stages. Additionally, we used DNA barcodes from larva and pupa specimens collected from three remote locations for molecular identification. The average pairwise divergence of all sequences in this study was 0.51%, well below the 2% to 3% (K-2-parameter) threshold set for one species. All sample sequences matched the R. maculosus morphospecies (KX657706.1 and KX657707.1), with 99.23% to 100% (sequence identity, E value: 0.00) matching success. The tree based on barcodes placed the specimens into the Rhynchaenus group, and the phylogenetic relationship between 62 sequences (30 samples and 32 from GeneBank) had high congruence with the morphospecies taxa. The traditional DNA barcodes were successfully transformed into quick response codes with larger coding capacity for information storage. The results showed that DNA barcoding is reliable for R. maculosus identification. The integration of molecular and morphology-based methods contributes to accurate species identification of this newly emerging oak pest. Full article

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

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17 pages, 696 KiB

Open AccessArticle

High Survivorship of First-Generation Monarch Butterfly Eggs to Third Instar Associated with a Diverse Arthropod Community

by Misty Stevenson, Kalynn L. Hudman, Alyx Scott, Kelsey Contreras and Jeffrey G. Kopachena

Insects 2021, 12(6), 567; https://doi.org/10.3390/insects12060567 - 21 Jun 2021

Cited by 4 | Viewed by 5949

Abstract

Based on surveys of winter roost sites, the eastern migratory population of the monarch butterfly (Danaus plexippus) in North America appears to have declined in the last 20 years and this has prompted the implementation of numerous conservation strategies. However, there [...] Read more.

Based on surveys of winter roost sites, the eastern migratory population of the monarch butterfly (Danaus plexippus) in North America appears to have declined in the last 20 years and this has prompted the implementation of numerous conservation strategies. However, there is little information on the survivorship of first-generation monarchs in the core area of occupancy in Texas, Oklahoma, and Louisiana where overwinter population recovery begins. The purpose of this study was to determine the survivorship of first-generation eggs to third instars at a site in north Texas and to evaluate host plant arthropods for their effect on survivorship. Survivorship to third instar averaged 13.4% and varied from 11.7% to 15.6% over three years. The host plants harbored 77 arthropod taxa, including 27 predatory taxa. Despite their abundance, neither predator abundance nor predator richness predicted monarch survival. However, host plants upon which monarchs survived often harbored higher numbers of non-predatory arthropod taxa and more individuals of non-predatory taxa. These results suggest that ecological processes may have buffered the effects of predators and improved monarch survival in our study. The creation of diverse functional arthropod communities should be considered for effective monarch conservation, particularly in southern latitudes. Full article

(This article belongs to the Collection Butterfly Diversity and Conservation)

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16 pages, 2547 KiB

Open AccessArticle

Analysis of Honeybee Drone Activity during the Mating Season in Northwestern Argentina

by Maria Marta Ayup, Philipp Gärtner, José L. Agosto-Rivera, Peter Marendy, Paulo de Souza and Alberto Galindo-Cardona

Insects 2021, 12(6), 566; https://doi.org/10.3390/insects12060566 - 21 Jun 2021

Cited by 7 | Viewed by 4262

Abstract

Males in Hymenopteran societies are understudied in many aspects and it is assumed that they only have a reproductive function. We studied the time budget of male honey bees, drones, using multiple methods. Changes in the activities of animals provide important information on [...] Read more.

Males in Hymenopteran societies are understudied in many aspects and it is assumed that they only have a reproductive function. We studied the time budget of male honey bees, drones, using multiple methods. Changes in the activities of animals provide important information on biological clocks and their health. Yet, in nature, these changes are subtle and often unobservable without the development and use of modern technology. During the spring and summer mating season, drones emerge from the hive, perform orientation flights, and search for drone congregation areas for mating. This search may lead drones to return to their colony, drift to other colonies (vectoring diseases and parasites), or simply get lost to predation. In a low percentage of cases, the search is successful, and drones mate and die. Our objective was to describe the activity of Apis mellifera drones during the mating season in Northwestern Argentina using three methods: direct observation, video recording, and radio frequency identification (RFID). The use of RFID tagging allows the tracking of a bee for 24 h but does not reveal the detailed activity of drones. We quantified the average number of drones’ departure and arrival flights and the time outside the hive. All three methods confirmed that drones were mostly active in the afternoon. We found no differences in results between those obtained by direct observation and by video recording. RFID technology enabled us to discover previously unknown drone behavior such as activity at dawn and during the morning. We also discovered that drones may stay inside the hive for many days, even after initiation of search flights (up to four days). Likewise, we observed drones to leave the hive for several days to return later (up to three days). The three methods were complementary and should be considered for the study of bee drone activity, which may be associated with the diverse factors influencing hive health. Full article

(This article belongs to the Special Issue Electronic Monitoring of Insects)

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13 pages, 1471 KiB

Open AccessArticle

Impact of Temperature on Survival Rate, Fecundity, and Feeding Behavior of Two Aphids, Aphis gossypii and Acyrthosiphon gossypii, When Reared on Cotton

by Jinping Liu, Chen Wang, Nicolas Desneux and Yanhui Lu

Insects 2021, 12(6), 565; https://doi.org/10.3390/insects12060565 - 21 Jun 2021

Cited by 15 | Viewed by 3795

Abstract

Aphid performance is sensitive to temperature changes. Previous studies found that Acyrthosiphon gossypii (Mordviiko) was more sensitive to high temperature than Aphis gossypii (Glover). However, the effects of high temperatures on the survival, fecundity, and feeding behavior of these two aphid adults are [...] Read more.

Aphid performance is sensitive to temperature changes. Previous studies found that Acyrthosiphon gossypii (Mordviiko) was more sensitive to high temperature than Aphis gossypii (Glover). However, the effects of high temperatures on the survival, fecundity, and feeding behavior of these two aphid adults are not clear. This study examined the effect of different temperatures (29 °C, 32 °C, and 35 °C) on the adult survival rate, fecundity, and feeding behavior of these two aphid species. Our results showed that the adverse effects of high temperatures (32 °C and 35 °C) on aphid adult survival and fecundity were greater for Ac. gossypii than Ap. gossypii. The electrical penetration graph (EPG) data showed that Ac. gossypii spent more time feeding on xylem than phloem under all temperature treatments, which contrasted with Ap. gossypii. The time of phloem ingestion by Ap. gossypii at 32 °C was significantly higher than at 29 °C, while for Ac. gossypii, this value significantly decreased when temperature increased. These feeding patterns indicate that Ac. gossypii obtains less nutrition from phloem in support of its development and fecundity. Data generated in this study will serve as the basis for predicting the effects of increased temperature on these two cotton aphids. Full article

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16 pages, 1292 KiB

Open AccessArticle

Bioactivity of Wild Hop Extracts against the Granary Weevil, Sitophilus granarius (L.)

by Gianluca Paventi, Giuseppe Rotundo, Marco Pistillo, Ilaria D’Isita and Giacinto Salvatore Germinara

Insects 2021, 12(6), 564; https://doi.org/10.3390/insects12060564 - 19 Jun 2021

Cited by 7 | Viewed by 2017

Abstract

The use of bioinsecticides, rather than synthetic compounds, appears a goal to be pursued in pest control, especially for species such as Sitophilus granarius (L.) which attack stored products. Since Humulus lupulus (L.) is a remarkable source of bioactive compounds, this study investigated [...] Read more.

The use of bioinsecticides, rather than synthetic compounds, appears a goal to be pursued in pest control, especially for species such as Sitophilus granarius (L.) which attack stored products. Since Humulus lupulus (L.) is a remarkable source of bioactive compounds, this study investigated the bioactivity of hop flower extracts against S. granarius adults by evaluating toxic (contact, inhalation, and ingestion), repellent, antifeedant, and nutritional effects as well as their anticholinesterase activity and olfactory sensitivity. Hop extracts were obtained by soaking dried and ground hop cones in solvents of decreasing polarity: methanol, acetone, and n-hexane. Dried crude extracts were resuspended in each solvent, and used in topical application, ingestion, and fumigation toxicity assays, as well as in contact and short-range repellency tests, in vitro anticholinesterase activity evaluation, and electroantennographic tests. No inhalation toxicity for the extracts was found. On the contrary, all extracts showed adult contact toxicity 24 h after treatment (LD_50/LD₉₀ 16.17/33.20, 25.77/42.64, and 31.07/49.48 µg/adult for acetone, n-hexane, and methanol extracts, respectively); negligible variations for these values at 48 h were found. The anticholinesterase activity shown by all extracts suggested that the inhibition of this enzyme was one of the mechanisms of action. Interestingly, flour disk bioassays revealed a significant ingestion toxicity for the acetone extract and a lower toxicity for the other two extracts. Moreover, all extracts affected insect nutritional parameters, at the highest dose checked. Filter paper and two-choice pitfall bioassays showed repellent activity and a strong reduction of insect orientation to a highly attractive food odor source, with minor differences among extracts, respectively. Finally, the presence of volatile compounds in the different extracts that are perceived by insect antennae was confirmed by electroantennography. All these findings strongly suggest a possible use of hop cone extracts against S. granarius, thus further confirming this plant as an interesting species for pest control. Full article

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23 pages, 1045 KiB

Open AccessArticle

The Draft Genome of Yellow Stem Borer, an Agriculturally Important Pest, Provides Molecular Insights into Its Biology, Development and Specificity Towards Rice for Infestation

by Divya Kattupalli, Kalyani M. Barbadikar, Vishalakshi Balija, Suneel Ballichatla, Athulya R, Ayyagari Phani Padmakumari, Swati Saxena, Kishor Gaikwad, Sridhar Yerram, Premalatha Kokku and Maganti Sheshu Madhav

Insects 2021, 12(6), 563; https://doi.org/10.3390/insects12060563 - 19 Jun 2021

Cited by 6 | Viewed by 3607

Abstract

Yellow stem borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), a major monophagous insect pest of rice, causes significant yield losses. The rice–YSB interaction is very dynamic, making it difficult for management. The development of resistant lines has been unsuccessful as there are no [...] Read more.

Yellow stem borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), a major monophagous insect pest of rice, causes significant yield losses. The rice–YSB interaction is very dynamic, making it difficult for management. The development of resistant lines has been unsuccessful as there are no effective resistant sources in the germplasm. Genome information is necessary for a better understanding of interaction with rice in terms of its recognition, response, and infestation mechanism. The draft genome of YSB is predicted to have 46,057 genes with an estimated size of 308 Mb, being correlated with the flow cytometry analysis. The existence of complex metabolic mechanisms and genes related to specific behavior was identified, being conditioned by a higher level of regulation. We deciphered the possible visual, olfactory, and gustatory mechanisms responsible for its evolution as a monophagous pest. Comparative genomic analysis revealed that YSB is unique in the way it has evolved. The obvious presence of high-immunity-related genes, well-developed RNAi machinery, and diverse effectors provides a means for developing genomic tools for its management. The identified 21,696 SSR markers can be utilized for diversity analysis of populations across the rice-growing regions. We present the first draft genome of YSB. The information emanated paves a way for biologists to design novel pest management strategies as well as for the industry to design new classes of safer and specific insecticide molecules. Full article

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15 pages, 4743 KiB

Open AccessArticle

Induction of a Compensatory Photosynthetic Response Mechanism in Tomato Leaves upon Short Time Feeding by the Chewing Insect Spodoptera exigua

by Julietta Moustaka, Nicolai Vitt Meyling and Thure Pavlo Hauser

Insects 2021, 12(6), 562; https://doi.org/10.3390/insects12060562 - 18 Jun 2021

Cited by 30 | Viewed by 2951

Abstract

In addition to direct tissue consumption, herbivory may affect other important plant processes. Here, we evaluated the effects of short-time leaf feeding by Spodoptera exigua larvae on the photosynthetic efficiency of tomato plants, using chlorophyll a fluorescence imaging analysis. After 15 min of [...] Read more.

In addition to direct tissue consumption, herbivory may affect other important plant processes. Here, we evaluated the effects of short-time leaf feeding by Spodoptera exigua larvae on the photosynthetic efficiency of tomato plants, using chlorophyll a fluorescence imaging analysis. After 15 min of feeding, the light used for photochemistry at photosystem II (PSII) (Φ_PSII), and the regulated heat loss at PSII (Φ_NPQ) decreased locally at the feeding zones, accompanied by increased non-regulated energy losses (Φ_NO) that indicated increased singlet oxygen (¹O₂) formation. In contrast, in zones neighboring the feeding zones and in the rest of the leaf, Φ_PSII increased due to a decreased Φ_NPQ. This suggests that leaf areas not directly affected by herbivory compensate for the photosynthetic losses by increasing the fraction of open PSII reaction centers (q_p) and the efficiency of these centers (Fv’/Fm’), because of decreased non-photochemical quenching (NPQ). This compensatory reaction mechanism may be signaled by singlet oxygen formed at the feeding zone. PSII functionality at the feeding zones began to balance with the rest of the leaf 3 h after feeding, in parallel with decreased compensatory responses. Thus, 3 h after feeding, PSII efficiency at the whole-leaf level was the same as before feeding, indicating that the plant managed to overcome the feeding effects with no or minor photosynthetic costs. Full article

(This article belongs to the Collection Plant Responses to Insect Herbivores)

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14 pages, 2189 KiB

Open AccessEditor’s ChoiceArticle

Molecular Evolution of Phototransduction Pathway Genes in Nocturnal and Diurnal Fireflies (Coleoptera: Lampyridae)

by Gavin J. Martin, Sarah E. Lower, Anton Suvorov and Seth M. Bybee

Insects 2021, 12(6), 561; https://doi.org/10.3390/insects12060561 - 18 Jun 2021

Cited by 2 | Viewed by 3493

Abstract

Most organisms are dependent on sensory cues from their environment for survival and reproduction. Fireflies (Coleoptera: Lampyridae) represent an ideal system for studying sensory niche adaptation due to many species relying on bioluminescent communication; as well as a diversity of ecologies. Here; using [...] Read more.

Most organisms are dependent on sensory cues from their environment for survival and reproduction. Fireflies (Coleoptera: Lampyridae) represent an ideal system for studying sensory niche adaptation due to many species relying on bioluminescent communication; as well as a diversity of ecologies. Here; using transcriptomics; we examine the phototransduction pathway in this non-model organism; and provide some of the first evidence for positive selection in the phototransduction pathway beyond opsins in beetles. Evidence for gene duplications within Lampyridae are found in inactivation no afterpotential C and inactivation no afterpotential D. We also find strong support for positive selection in arrestin-2; inactivation no afterpotential D; and transient receptor potential-like; with weak support for positive selection in guanine nucleotide-binding protein G(q) subunit alpha and neither inactivation nor afterpotential C. Taken with other recent work in flies; butterflies; and moths; this represents an exciting new avenue of study as we seek to further understand diversification and constraint on the phototransduction pathway in light of organism ecology. Full article

(This article belongs to the Special Issue Systematics, Phylogeny, Evolution and Diversity of Elateridae (Coleoptera) and Their Relatives)

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9 pages, 1816 KiB

Open AccessArticle

Effect of Duration of Exposure to Males on Female Reproductive Performance of the Green Lacewing, Chrysoperla agilis (Neuroptera: Chrysopidae)

by Konstantinos Athanasiadis, Maria L. Pappas and George D. Broufas

Insects 2021, 12(6), 560; https://doi.org/10.3390/insects12060560 - 18 Jun 2021

Cited by 1 | Viewed by 1982

Abstract

Chrysoperla agilis Henry et al. is one of the five cryptic species of the carnea group found in Europe. They are known to widely occur in agricultural fields and survive and reproduce in a wide range of temperatures. The reproductive biology of the [...] Read more.

Chrysoperla agilis Henry et al. is one of the five cryptic species of the carnea group found in Europe. They are known to widely occur in agricultural fields and survive and reproduce in a wide range of temperatures. The reproductive biology of the cryptic species is poorly known, especially regarding the number of matings required for the females’ maximum reproductive output. We recorded the egg production and longevity of virgin females, as well as of females that had access to males for 1 week or for their lifetime. Longevity of C. agilis females with access to males was similar whether these were present for 1 week or for their lifetime (64.8 and 66.1 days, respectively). On the other hand, oviposition was higher in the long-term exposure to males (302.1 vs. 421.1 eggs, respectively). Virgin females lived longer (94.1 days) than mated females and laid a low number (54.5) of (unfertile) eggs. Egg hatchability and progeny sex ratio were similar in treatments with males. Nevertheless, the highest value (0.1321) of intrinsic rate of increase (r_m) was recorded when females were continuously exposed to males. These results are relevant to biological control and could be applicable in mass-rearing C. agilis and predicting its population dynamics in the field. Full article

(This article belongs to the Special Issue Applied Insect Reproductive Biology)

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17 pages, 4906 KiB

Open AccessArticle

Identification of 35 C-Type Lectins in the Oriental Armyworm, Mythimna separata (Walker)

by Hao Li, Fang-Fang Liu, Li-Qing Fu, Ze Liu, Wen-Ting Zhang, Qian Wang and Xiang-Jun Rao

Insects 2021, 12(6), 559; https://doi.org/10.3390/insects12060559 - 16 Jun 2021

Cited by 11 | Viewed by 1914

Abstract

Insect C-type lectins (CTLs) play vital roles in modulating humoral and cellular immune responses. The oriental armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae) is a migratory pest that causes significant economic loss in agriculture. CTLs have not yet been systematically identified in M. separata [...] Read more.

Insect C-type lectins (CTLs) play vital roles in modulating humoral and cellular immune responses. The oriental armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae) is a migratory pest that causes significant economic loss in agriculture. CTLs have not yet been systematically identified in M. separata. In this study, we first constructed a transcriptome of M. separata larvae, generating a total of 45,888 unigenes with an average length of 910 bp. Unigenes were functionally annotated in six databases: NR, GO, KEGG, Pfam, eggNOG, and Swiss-Prot. Unigenes were enriched in functional pathways, such as those of signal transduction, endocrine system, cellular community, and immune system. Thirty-five unigenes encoding C-type lectins were identified, including CTL-S1~CTL-S6 (single CRD) and IML-1~IML-29 (dual CRD). Phylogenetic analyses showed dramatic lineage-specific expansions of IMLs. Sequence alignment and structural modeling identified potential ligand-interacting residues. Real-time qPCR revealed that CTL-Ss mainly express in eggs and early stage larvae, while IMLs mainly express in mid-late-stage larvae, pupae, and adults. In naïve larvae, hemocytes, fat body, and epidermis are the major tissues that express CTLs. In larvae challenged by Escherichia coli, Staphylococcus aureus, or Beauveria bassiana, the expression of different CTLs was stimulated in hemocytes, fat body and midgut. The present study will help further explore functions of M. separata CTLs. Full article

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

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12 pages, 626 KiB

Open AccessArticle

Effect of Cold Storage on the Quality of Psyttalia incisi (Hymenoptera: Braconidae), a Larval Parasitoid of Bactrocera dorsalis (Diptera: Tephritidae)

by Jia Lin, Deqing Yang, Xuxing Hao, Pumo Cai, Yaqing Guo, Shuang Shi, Changming Liu and Qinge Ji

Insects 2021, 12(6), 558; https://doi.org/10.3390/insects12060558 - 16 Jun 2021

Cited by 13 | Viewed by 1881

Abstract

Psyttalia incisi (Silvestri) is the dominant parasitoid against Bactrocera dorsalis (Hendel) in fruit-producing regions of southern China. Prior to a large-scale release, it is important to generate a sufficient stockpile of P. incisi whilst considering how best to maintain their quality and performance; [...] Read more.

Psyttalia incisi (Silvestri) is the dominant parasitoid against Bactrocera dorsalis (Hendel) in fruit-producing regions of southern China. Prior to a large-scale release, it is important to generate a sufficient stockpile of P. incisi whilst considering how best to maintain their quality and performance; cold storage is an ideal method to achieve these aims. In this study, the impacts of temperature and storage duration on the developmental parameters of P. incisi pupae at different age intervals were assessed. Then, four of the cold storage protocols were chosen for further evaluating their impacts on the quality parameters of post-storage adults. Results showed that the emergence rate of P. incisi was significantly affected by storage temperature, storage duration, and pupal age interval and their interactions. However, when late-age P. incisi pupae developed at a temperature of 13 °C for 10 or 15 d, no undesirable impacts on dry weight, flight ability, longevity, reproduction parameters of post-storage adults, emergence rate, or the female proportion of progeny were recorded. Our findings demonstrate that cold storage has the potential for enhancing the flexibility and effectiveness of the large-scale production and application of P. incisi. Full article

(This article belongs to the Special Issue Focus on Insect Rearing Methodology to Promote Scientific Research and Mass Production)

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9 pages, 996 KiB

Open AccessReview

Edible Insects and Sustainable Development Goals

by Roberta Moruzzo, Simone Mancini and Alessandra Guidi

Insects 2021, 12(6), 557; https://doi.org/10.3390/insects12060557 - 15 Jun 2021

Cited by 44 | Viewed by 8110

Abstract

The insect sector can become an important component of sustainable circular agriculture by closing nutrient and energy cycles, fostering food security, and minimising climate change and biodiversity loss, thereby contributing to SDGs. The high levels of the interaction of the insect sector with [...] Read more.

The insect sector can become an important component of sustainable circular agriculture by closing nutrient and energy cycles, fostering food security, and minimising climate change and biodiversity loss, thereby contributing to SDGs. The high levels of the interaction of the insect sector with the SDGs is clearly illustrated inside the review, analysing all of the SDGs that can have direct and indirect effects on insects. Mapping the interactions between the SDGs goals and insect sector offers a starting point, from which it could be possible to define practical next steps for better insect policy. Full article

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13 pages, 6080 KiB

Open AccessArticle

Novel RNA Viruses from the Transcriptome of Pheromone Glands in the Pink Bollworm Moth, Pectinophora gossypiella

by Xiaoyi Dou, Sijun Liu, Victoria Soroker, Ally Harari and Russell Jurenka

Insects 2021, 12(6), 556; https://doi.org/10.3390/insects12060556 - 15 Jun 2021

Cited by 6 | Viewed by 1948

Abstract

In this study, we analyzed the transcriptome obtained from the pheromone gland isolated from two Israeli populations of the pink bollworm Pectinophora gossypiella to identify viral sequences. The lab population and the field samples carried the same viral sequences. We discovered four novel [...] Read more.

In this study, we analyzed the transcriptome obtained from the pheromone gland isolated from two Israeli populations of the pink bollworm Pectinophora gossypiella to identify viral sequences. The lab population and the field samples carried the same viral sequences. We discovered four novel viruses: two positive-sense single-stranded RNA viruses, Pectinophora gossypiella virus 1 (PecgV1, a virus of Iflaviridae) and Pectinophora gossypiella virus 4 (PecgV4, unclassified), and two negative-sense single-stranded RNA viruses, Pectinophora gossypiella virus 2 (PecgV2, a virus of Phasmaviridae) and Pectinophora gossypiella virus 3 (PecgV3, a virus of Phenuiviridae). In addition, sequences derived from two negative-sense single-stranded RNA viruses that belong to Mononegavirales were found in the data. Analysis of previous transcriptome sequencing data derived from the midgut of pink bollworm larvae of a USA population only identified PecgV1, but no other viruses. High viral sequence coverages of PecgV1 and PecgV4 were observed in both field and lab populations. This is the first report of viral sequences discovered from the pink bollworm. Results from this investigation suggest that the pink bollworm harbors multiple viruses. Further investigation of the viral pathogens may help to develop novel pest management strategies for control of the pink bollworm. Full article

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15 pages, 1961 KiB

Open AccessArticle

Phylogeographic Investigation of an Endangered Longhorn Beetle, Callipogon relictus (Coleoptera: Cerambycidae), in Northeast Asia: Implications for Future Restoration in Korea

by Ji Hyoun Kang, Dae-Am Yi, Alexander V. Kuprin, Changdo Han and Yeon Jae Bae

Insects 2021, 12(6), 555; https://doi.org/10.3390/insects12060555 - 15 Jun 2021

Cited by 2 | Viewed by 2850

Abstract

The longhorn beetle, Callipogon (Eoxenus) relictus Semenov, is the only remnant species found in the Palearctic region, while all other Callipogon species are distributed mainly in Central America and partly in South America. This species has been placed in the first [...] Read more.

The longhorn beetle, Callipogon (Eoxenus) relictus Semenov, is the only remnant species found in the Palearctic region, while all other Callipogon species are distributed mainly in Central America and partly in South America. This species has been placed in the first category (as ‘critically endangered’) of the Red Data Book in Russia and designated as one of the top-priority target species among all endangered invertebrate species for restoration in South Korea since 2006. Although its restricted distribution in Northeast Asia with a high conservational value has been highlighted, genetic features of C. relictus from different geographic regions remain unexplored. We first investigated the level of genetic diversity and phylogeographic patterns of C. relictus to evaluate the current conservational status and the feasibility of the implementation of a restoration program. The average genetic divergence of mitochondrial gene COI based on Kimura-2-parameter distance among the four regions in Russia, China, North Korea, and South Korea was 2.2%, which lies within the range of intraspecific levels. However, two separate clades with 3.8% divergence were identified, despite no geographical clustering of haplotypes. The linear pattern of the haplotype network with a high level of haplotype and nucleotide diversities suggests that the wide range of currently fragmented populations might be the remnant of genetically diverse populations in the past. This study will provide crucial information on the genetic characteristics and phylogeographic history of C. relictus, which will help to establish conservation strategies for this cherished insect species in Northeast Asia. Full article

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

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12 pages, 1191 KiB

Open AccessArticle

Serosurvey of Nonhuman Primates in Costa Rica at the Human–Wildlife Interface Reveals High Exposure to Flaviviruses

by Andrea Chaves, Martha Piche-Ovares, Carlos N. Ibarra-Cerdeña, Eugenia Corrales-Aguilar, Gerardo Suzán, Andres Moreira-Soto and Gustavo A. Gutiérrez-Espeleta

Insects 2021, 12(6), 554; https://doi.org/10.3390/insects12060554 - 15 Jun 2021

Cited by 8 | Viewed by 3827

Abstract

Arthropod-borne viruses belonging to the flavivirus genus possess an enormous relevance in public health. Neotropical non-human primates (NPs) have been proposed to be susceptible to flavivirus infections due to their arboreal and diurnal habits, their genetic similarity to humans, and their relative closeness [...] Read more.

Arthropod-borne viruses belonging to the flavivirus genus possess an enormous relevance in public health. Neotropical non-human primates (NPs) have been proposed to be susceptible to flavivirus infections due to their arboreal and diurnal habits, their genetic similarity to humans, and their relative closeness to humans. However, the only known flavivirus in the American continent maintained by sylvatic cycles involving NPs is yellow fever virus (YFV), and NPs’ role as potential hosts of other flaviviruses is still unknown. Here, we examined flavivirus exposure in 86 serum samples including 83.7% samples from free-range and 16.3% from captive NPs living in flavivirus-endemic regions of Costa Rica. Serum samples were opportunistically collected throughout Costa Rica in 2000–2015. We used a highly specific micro-plaque reduction neutralization test (micro-PRNT) to determine the presence of antibodies against YFV, dengue virus 1–4 (DENV), Zika virus, West Nile virus (WNV), and Saint Louis encephalitis virus (SLEV). We found evidence of seropositive NPs with homotypic reactivity to SLEV 11.6% (10/86), DENV 10.5% (9/86), and WNV 2.3% (2/86). Heterotypic reactivity was determined in 3.5% (3/86) of individuals against DENV, 1.2% (1/86) against SLEV, and 1.2% (1/86) against WNV. We found that 13.9% (12/86) of NPs were positive for an undetermined flavivirus species. No antibodies against DENV-3, DENV-4, YFV, or ZIKV were found. This work provides compelling serological evidence of flavivirus exposure in Costa Rican NPs, in particular to DENV, SLEV, and WNV. The range of years of sampling and the region from where positives were detected coincide with those in which peaks of DENV in human populations were registered, suggesting bidirectional exposure due to human–wildlife contact or bridging vectors. Our work suggests the continuous exposure of wildlife populations to various flaviviruses of public health importance and underscores the necessity of further surveillance of flaviviruses at the human–wildlife interface in Central America. Full article

(This article belongs to the Special Issue Impacts of Ecological Perturbations at the Host-Vector-Pathogen Interface under Global Change)

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11 pages, 1144 KiB

Open AccessArticle

Development of DNA Melt Curve Analysis for the Identification of Lepidopteran Pests in Almonds and Pistachios

by Rohith Vulchi, Kent M. Daane and Jacob A. Wenger

Insects 2021, 12(6), 553; https://doi.org/10.3390/insects12060553 - 15 Jun 2021

Cited by 1 | Viewed by 2949

Abstract

Almonds and pistachios are fed upon by a diverse assemblage of lepidopteran insects, several of which are economically important pests. Unfortunately, identification of these pests can be difficult, as specimens are frequently damaged during collection, occur in traps with non-target species, and are [...] Read more.

Almonds and pistachios are fed upon by a diverse assemblage of lepidopteran insects, several of which are economically important pests. Unfortunately, identification of these pests can be difficult, as specimens are frequently damaged during collection, occur in traps with non-target species, and are morphologically similar up to their third instar. Here, we present a quantitative PCR based melt curve analysis for simple, rapid, and accurate identification of six lepidopteran pests of almonds and pistachios: navel orangeworm (Amyelois transitella), peach twig borer (Anarsia lineatella), oriental fruit moth (Grapholita molesta), obliquebanded leafroller (Choristoneura rosaceana), raisin moth (Cadra figulilella), and Indian meal moth (Plodia interpunctella). In this approach, the dissociation (melt) temperature(s) of a 658 bp section of cytochrome c oxidase subunit 1 was determined using quantitative PCR (qPCR). Within these six species, the distribution and the number of melt peak temperatures provide an unambiguous species level identification that is reproducible when unsheared DNA can be extracted. The test is robust across a variety of sampling approaches including insects removed from sticky card traps, museum specimens, and samples that were left in the field for up to 7 days. The melt curve’s simplicity allows it to be performed in any basic molecular biology laboratory with a quantitative PCR. Full article

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

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9 pages, 1741 KiB

Open AccessArticle

CRISPR-Mediated Endogenous Activation of Fibroin Heavy Chain Gene Triggers Cellular Stress Responses in Bombyx mori Embryonic Cells

by Wenbo Hu, Xiaogang Wang, Sanyuan Ma, Zhangchuan Peng, Yang Cao and Qingyou Xia

Insects 2021, 12(6), 552; https://doi.org/10.3390/insects12060552 - 13 Jun 2021

Cited by 5 | Viewed by 3037

Abstract

The silkworm Bombyx mori is an economically important insect, as it is the main producer of silk. Fibroin heavy chain (FibH) gene, encoding the core component of silk protein, is specifically and highly expressed in silk gland cells but not in [...] Read more.

The silkworm Bombyx mori is an economically important insect, as it is the main producer of silk. Fibroin heavy chain (FibH) gene, encoding the core component of silk protein, is specifically and highly expressed in silk gland cells but not in the other cells. Although the silkworm FibH gene has been well studied in transcriptional regulation, its biological functions in the development of silk gland cells remain elusive. In this study, we constructed a CRISPRa system to activate the endogenous transcription of FibH in Bombyx mori embryonic (BmE) cells, and the mRNA expression of FibH was successfully activated. In addition, we found that FibH expression was increased to a maximum at 60 h after transient transfection of sgRNA/dCas9-VPR at a molar ratio of 9:1. The qRT-PCR analysis showed that the expression levels of cellular stress response-related genes were significantly up-regulated along with activated FibH gene. Moreover, the lyso-tracker red and monodansylcadaverine (MDC) staining assays revealed an apparent appearance of autophagy in FibH-activated BmE cells. Therefore, we conclude that the activation of FibH gene leads to up-regulation of cellular stress responses-related genes in BmE cells, which is essential for understanding silk gland development and the fibroin secretion process in B. mori. Full article

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

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12 pages, 2764 KiB

Open AccessArticle

Eugenol and Thymol Derivatives as Antifeedant Agents against Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) Larvae

by Tay Karh Yan, Asnuzilawati Asari, Siti Aishah Salleh and Wahizatul Afzan Azmi

Insects 2021, 12(6), 551; https://doi.org/10.3390/insects12060551 - 13 Jun 2021

Cited by 8 | Viewed by 3037

Abstract

Coconut palms in Malaysia are infested by a destructive invasive pest, RPW since 2007, and the pest’s population is difficult to control. At present, RPW control management mainly relies on the use of monocrotophos, which is administered by the trunk injection method. However, [...] Read more.

Coconut palms in Malaysia are infested by a destructive invasive pest, RPW since 2007, and the pest’s population is difficult to control. At present, RPW control management mainly relies on the use of monocrotophos, which is administered by the trunk injection method. However, this pesticide can negatively impact human health and the ecosystem. Plant EO that can be used as a bio-pesticide is highly recommended as an alternative to monocrotophos because of its target-specific and eco-friendly properties. The antifeedant activity of eight eugenol and thymol derivatives from clove and thyme EOs were tested against the fourth instar larvae of RPW through oral bioassay for 14 days. Relative growth rate (RGR), relative consumption rate (RCR), the efficiency of conversion of ingested food (ECI), and the feeding deterrent index (FDI) were compared and analyzed. All of the derivatives showed antifeedant activity, particularly the eugenol derivative, 4-allyl-2-methoxy-1-(4-trifluoromethyl-benzyloxy)-benzene (FDI = 54.14%) and the thymol derivative, 2-isopropyl-4-methyl-2-((4-nitrobenzyl) oxy) benzene (FDI = 53.88%). Both of them showed promising results on their ability to be the most effective antifeedant agents in each derivative group. There was no significant difference in the effectiveness of the eugenol-based and thymol-based derivatives, but the ether derivative group (FDI = 45.63%) had a significantly stronger effect than the ester derivative group (FDI = 39.71%). This study revealed that the compound in ether form is more effective than the compound in ester form as an antifeedant agent against RPW larvae, regardless of the plant EO that the compound is derived from. Full article

(This article belongs to the Special Issue Management of True Weevils (Curculionidae))

20 pages, 369 KiB

Open AccessReview

A Review of Alternative Management Tactics Employed for the Control of Various Cockroach Species (Order: Blattodea) in the USA

by Ameya D. Gondhalekar, Arthur G. Appel, Gretchen M. Thomas and Alvaro Romero

Insects 2021, 12(6), 550; https://doi.org/10.3390/insects12060550 - 12 Jun 2021

Cited by 18 | Viewed by 6055

Abstract

Effective control of domestic and peridomestic cockroaches requires integrated approaches that emphasize concurrent use of chemicals with alternative control tactics. An integrated pest management (IPM) approach is particularly justified in environments where satisfactory cockroach control cannot be achieved due to multiple factors including [...] Read more.

Effective control of domestic and peridomestic cockroaches requires integrated approaches that emphasize concurrent use of chemicals with alternative control tactics. An integrated pest management (IPM) approach is particularly justified in environments where satisfactory cockroach control cannot be achieved due to multiple factors including development of insecticide aversion and resistance in some cockroach species, and poor sanitation or structural issues that foster infestations. While a flurry of research effort has been devoted to study alternative tactics for cockroach control, only a few of them have been evaluated in the context of IPM programs. This review focuses on examining studies on alternative tactics that are proven efficacious, economical, and logistically feasible for their inclusion in IPM programs for important domestic and peridomestic cockroaches in the USA. Management programs that educate the public on cockroach biology, behavior, and the importance of sanitation; use of traps to monitor infestation levels; apply targeted low impact insecticides such as baits, have demonstrated a greater success for effective and sustainable control of cockroaches when compared to an insecticide-only approach. Incorporation of other alternative control methods to IPM programs will require more applied research that validates their use in real-world scenarios and demonstrates their cost-effectiveness. Full article

(This article belongs to the Special Issue A Review of Household and Structural Pest Management with an Emphasis on Alternative Control Methods)

22 pages, 1276 KiB

Open AccessReview

Climate Mismatch between Introduced Biological Control Agents and Their Invasive Host Plants: Improving Biological Control of Tropical Weeds in Temperate Regions

by Nathan E. Harms, Ian A. Knight, Paul D. Pratt, Angelica M. Reddy, Abhishek Mukherjee, Ping Gong, Julie Coetzee, S. Raghu and Rodrigo Diaz

Insects 2021, 12(6), 549; https://doi.org/10.3390/insects12060549 - 12 Jun 2021

Cited by 22 | Viewed by 5001

Abstract

Many weed biological control programs suffer from large-scale spatial variation in success due to restricted distributions or abundances of agents in temperate climates. For some of the world’s worst aquatic weeds, agents are established but overwintering conditions limit their survival in higher latitudes [...] Read more.

Many weed biological control programs suffer from large-scale spatial variation in success due to restricted distributions or abundances of agents in temperate climates. For some of the world’s worst aquatic weeds, agents are established but overwintering conditions limit their survival in higher latitudes or elevations. The resulting need is for new or improved site- or region-specific biological control tools. Here, we review this challenge with a focus on low-temperature limitations of agents and propose a roadmap for improving success. Investigations across spatial scales, from global (e.g., foreign exploration), to local (selective breeding), to individual organisms (molecular modification), are discussed. A combination of traditional (foreign) and non-traditional (introduced range) exploration may lead to the discovery and development of better-adapted agent genotypes. A multivariate approach using ecologically relevant metrics to quantify and compare cold tolerance among agent populations is likely required. These data can be used to inform environmental niche modeling combined with mechanistic modeling of species’ fundamental climate niches and life histories to predict where, when, and at what abundance agents will occur. Finally, synthetic and systems biology approaches in conjunction with advanced modern genomics, gene silencing and gene editing technologies may be used to identify and alter the expression of genes enhancing cold tolerance, but this technology in the context of weed biological control has not been fully explored. Full article

(This article belongs to the Special Issue Biological Control of Invasive Plants Using Arthropods)

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12 pages, 4652 KiB

Open AccessArticle

Listening to Slugs: Acceptability and Consumption of Molluscicide Pellets by the Grey Field Slug, Deroceras reticulatum

by Samantha Mirhaya de Silva, David Chesmore, Jack Smith and Gordon Port

Insects 2021, 12(6), 548; https://doi.org/10.3390/insects12060548 - 11 Jun 2021

Cited by 1 | Viewed by 2755

Abstract

Gastropod damage to crop plants has a significant economic impact on agricultural and horticultural industries worldwide, with the Grey Field Slug (Deroceras reticulatum (Müller)) considered the main mollusc pest in the United Kingdom and in many other temperate areas. The prevailing form [...] Read more.

Gastropod damage to crop plants has a significant economic impact on agricultural and horticultural industries worldwide, with the Grey Field Slug (Deroceras reticulatum (Müller)) considered the main mollusc pest in the United Kingdom and in many other temperate areas. The prevailing form of crop protection is pellets containing the active ingredient, metaldehyde. Metaldehyde can cause paralysis and death in the mollusc, depending on the amount ingested. The paralysing effects may result in reduced pellet consumption. A greater understanding of metaldehyde consumption may reveal an area that can be manipulated using novel molluscicide formulations. Novel pellet types included commercial metaldehyde pellets coated so that metaldehyde is released more slowly. In both laboratory and arena trials, an audio sensor was used to record individual slugs feeding on a variety of pellet types, including commercially available toxic pellets (metaldehyde and ferric phosphate) and novel metaldehyde formulations. The sensor was used to record the length of each bite and the total number of bites. There was no significant difference in the length of bites between pellet types in laboratory trials. Novel pellets were not consumed more than commercial pellet types. Commercial pellet types did not differ in consumption. Full article

(This article belongs to the Special Issue Biology and Management of Slug and Snail Pests)

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25 pages, 3084 KiB

Open AccessReview

Fat Body—Multifunctional Insect Tissue

by Patrycja Skowronek, Łukasz Wójcik and Aneta Strachecka

Insects 2021, 12(6), 547; https://doi.org/10.3390/insects12060547 - 11 Jun 2021

Cited by 54 | Viewed by 7236

Abstract

The biodiversity of useful organisms, e.g., insects, decreases due to many environmental factors and increasing anthropopressure. Multifunctional tissues, such as the fat body, are key elements in the proper functioning of invertebrate organisms and resistance factors. The fat body is the center of [...] Read more.

The biodiversity of useful organisms, e.g., insects, decreases due to many environmental factors and increasing anthropopressure. Multifunctional tissues, such as the fat body, are key elements in the proper functioning of invertebrate organisms and resistance factors. The fat body is the center of metabolism, integrating signals, controlling molting and metamorphosis, and synthesizing hormones that control the functioning of the whole body and the synthesis of immune system proteins. In fat body cells, lipids, carbohydrates and proteins are the substrates and products of many pathways that can be used for energy production, accumulate as reserves, and mobilize at the appropriate stage of life (diapause, metamorphosis, flight), determining the survival of an individual. The fat body is the main tissue responsible for innate and acquired humoral immunity. The tissue produces bactericidal proteins and polypeptides, i.e., lysozyme. The fat body is also important in the early stages of an insect’s life due to the production of vitellogenin, the yolk protein needed for the development of oocytes. Although a lot of information is available on its structure and biochemistry, the fat body is an interesting research topic on which much is still to be discovered. Full article

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

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22 pages, 2450 KiB

Open AccessArticle

A Three-Pronged Approach to Studying Sublethal Insecticide Doses: Characterising Mosquito Fitness, Mosquito Biting Behaviour, and Human/Environmental Health Risks

by Mara Moreno-Gómez, Rubén Bueno-Marí and Miguel. A. Miranda

Insects 2021, 12(6), 546; https://doi.org/10.3390/insects12060546 - 11 Jun 2021

Cited by 5 | Viewed by 3232

Abstract

Worldwide, pyrethroids are one of the most widely used insecticide classes. In addition to serving as personal protection products, they are also a key line of defence in integrated vector management programmes. Many studies have assessed the effects of sublethal pyrethroid doses on [...] Read more.

Worldwide, pyrethroids are one of the most widely used insecticide classes. In addition to serving as personal protection products, they are also a key line of defence in integrated vector management programmes. Many studies have assessed the effects of sublethal pyrethroid doses on mosquito fitness and behaviour. However, much remains unknown about the biological, physiological, demographic, and behavioural effects on individual mosquitoes or mosquito populations when exposure occurs via spatial treatments. Here, females and males of two laboratory-reared mosquito species, Culex pipiens and Aedes albopictus, were exposed to five different treatments: three doses of the pyrethroid prallethrin, as well as an untreated and a negative control. The effects of each treatment on mosquito species, sex, adult mortality, fertility, F1 population size, and biting behaviour were also evaluated. To compare knockdown and mortality among treatments, Mantel–Cox log-rank tests were used. The results showed that sublethal doses reduced mosquito survival, influencing population size in the next generation. They also provided 100% protection to human hosts and presented relatively low risks to human and environmental health. These findings emphasise the need for additional studies that assess the benefits of using sublethal doses as part of mosquito management strategies. Full article

(This article belongs to the Special Issue Insecticides for Mosquito Control: Strengthening the Evidence Base)

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10 pages, 1503 KiB

Open AccessCommunication

Nesting, Sex Ratio and Natural Enemies of the Giant Resin Bee in Relation to Native Species in Europe

by Sara Straffon-Díaz, Luca Carisio, Aulo Manino, Paolo Biella and Marco Porporato

Insects 2021, 12(6), 545; https://doi.org/10.3390/insects12060545 - 11 Jun 2021

Cited by 12 | Viewed by 3254

Abstract

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with [...] Read more.

Megachile sculpturalis (Smith, 1853) is the first exotic bee species in Europe. Its remarkably fast expansion across this continent is leading to a growing concern on the extent of negative impacts to the native fauna. To evaluate the interactions of exotic bees with local wild bees, we set up trap nests for above-ground nesting bees on a semi-urban area of north-western Italy. We aimed to investigate the interaction in artificial traps between the exotic and native wild bees and to assess offspring traits accounting for exotic bee fitness: progeny sex ratio and incidence of natural enemies. We found that the tunnels occupied by exotic bees were already cohabited by O. cornuta, and thus the cells of later nesting alien bees may block the native bee emergence for the next year. The progeny sex ratio of M. sculpturalis was strongly unbalanced toward males, indicating a temporary adverse population trend in the local invaded area. In addition, we documented the presence of three native natural enemies affecting the brood of the exotic bee. Our results bring out new insights on how the M. sculpturalis indirectly competes with native species and on its performance in new locations. Full article

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

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27 pages, 3912 KiB

Open AccessReview

Resistance in the Genus Spodoptera: Key Insect Detoxification Genes

by Frédérique Hilliou, Thomas Chertemps, Martine Maïbèche and Gaëlle Le Goff

Insects 2021, 12(6), 544; https://doi.org/10.3390/insects12060544 - 11 Jun 2021

Cited by 54 | Viewed by 5867

Abstract

The genus Spodoptera (Lepidoptera: Noctuidae) includes species that are among the most important crop pests in the world. These polyphagous species are able to feed on many plants, including corn, rice and cotton. In addition to their ability to adapt to toxic compounds [...] Read more.

The genus Spodoptera (Lepidoptera: Noctuidae) includes species that are among the most important crop pests in the world. These polyphagous species are able to feed on many plants, including corn, rice and cotton. In addition to their ability to adapt to toxic compounds produced by plants, they have developed resistance to the chemical insecticides used for their control. One of the main mechanisms developed by insects to become resistant involves detoxification enzymes. In this review, we illustrate some examples of the role of major families of detoxification enzymes such as cytochromes P450, carboxyl/cholinesterases, glutathione S-transferases (GST) and transporters such as ATP-binding cassette (ABC) transporters in insecticide resistance. We compare available data for four species, Spodoptera exigua, S. frugiperda, S. littoralis and S. litura. Molecular mechanisms underlying the involvement of these genes in resistance will be described, including the duplication of the CYP9A cluster, over-expression of GST epsilon or point mutations in acetylcholinesterase and ABCC2. This review is not intended to be exhaustive but to highlight the key roles of certain genes. Full article

(This article belongs to the Special Issue Recent Advances in the Understanding of Molecular Mechanisms of Resistance in Noctuid Pests)

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3 pages, 183 KiB

Open AccessEditorial

Recent Advances in Postharvest Pest Biology and Management

by George N. Mbata and Michael D. Toews

Insects 2021, 12(6), 543; https://doi.org/10.3390/insects12060543 - 11 Jun 2021

Cited by 1 | Viewed by 1779

Abstract

A sizable proportion (about 8%) of the world population is facing food insecurity [...] Full article

(This article belongs to the Special Issue Recent Advances in Postharvest Pest Biology and Management)

14 pages, 2951 KiB

Open AccessArticle

Historical Changes in Honey Bee Wing Venation in Romania

by Adam Tofilski, Eliza Căuia, Adrian Siceanu, Gabriela Oana Vișan and Dumitru Căuia

Insects 2021, 12(6), 542; https://doi.org/10.3390/insects12060542 - 10 Jun 2021

Cited by 6 | Viewed by 3537

Abstract

The honey bee (Apis mellifera) is an ecologically and economically important species that provides pollination services to natural and agricultural systems. The biodiversity of the honey bee is being endangered by the mass import of non-native queens. In many locations, it [...] Read more.

The honey bee (Apis mellifera) is an ecologically and economically important species that provides pollination services to natural and agricultural systems. The biodiversity of the honey bee is being endangered by the mass import of non-native queens. In many locations, it is not clear how the local populations have been affected by hybridisation between native and non-native bees. There is especially little information about temporal changes in hybridisation. In Romania, A. m. carpatica naturally occurs, and earlier studies show that there are two subpopulations separated by the Carpathian Mountains. In this study, we investigated how the arrangement of veins in bees’ wings (venation) has changed in Romanian honey bees in the last four decades. We found that in the contemporary population of Romanian bees, there are still clear differences between the intra- and extra-Carpathian subpopulations, which indicates that natural variation among honey bees is still being preserved. We also found significant differences between bees collected before and after 2000. The observed temporal changes in wing venation are most likely caused by hybridisation between native bees and non-native bees sporadically introduced by beekeepers. In order to facilitate conservation and the monitoring of native Romanian bees, we developed a method facilitating their identification. Full article

(This article belongs to the Special Issue Diversity of Honey Bee: Morphology and Genetics)

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19 pages, 356 KiB

Open AccessReview

A Literature Review of Biological and Bio-Rational Control Strategies for Slugs: Current Research and Future Prospects

by Archita Barua, Christopher D. Williams and Jenna L. Ross

Insects 2021, 12(6), 541; https://doi.org/10.3390/insects12060541 - 10 Jun 2021

Cited by 21 | Viewed by 5859

Abstract

Terrestrial gastropod molluscs (slugs and snails) (Mollusca: Gastropoda) cause significant crop damage around the world. There is no formal approach for differentiating between slugs and snails; however, an organism is usually considered a slug when there is no external shell, or when the [...] Read more.

Terrestrial gastropod molluscs (slugs and snails) (Mollusca: Gastropoda) cause significant crop damage around the world. There is no formal approach for differentiating between slugs and snails; however, an organism is usually considered a slug when there is no external shell, or when the shell is small in comparison to the body, and a snail when there is a large external shell. Although snails are an important pest of many crops, this review focuses on slug pests and their nonchemical control measures. A recent study by the UK Agriculture and Horticulture Development Board concluded that the failure to control slugs could cost the UK agriculture industry over GBP 100 million annually, with similar figures reported around the world. Whilst slugs are mostly controlled using chemical molluscicide products, some actives have come under scrutiny due to their detrimental environmental effects and impact on nontarget organisms. This has resulted in the ban of actives such as methiocarb in the UK and EU, and, more recently, the ban of metaldehyde in the UK. Therefore, there is an urgent need to find alternative and effective nontoxic solutions in the interest of global food security. In this paper, we have integrated extant literature on the three main biological control agents of slugs, namely nematodes, carabid beetles and sciomyzid flies, and various promising bio-rational slug control strategies. The review also highlights current research gaps and indicates some relevant potential future directions towards developing environmentally benign slug control solutions. Full article

(This article belongs to the Special Issue Biology and Management of Slug and Snail Pests)

11 pages, 848 KiB

Open AccessArticle

Differences in Life History Traits in Rural vs. Urban Populations of a Specialist Ground Beetle, Carabus convexus

by Tibor Magura, Szabolcs Mizser, Roland Horváth, Dávid D. Nagy, Mária Tóth, Réka Csicsek and Gábor L. Lövei

Insects 2021, 12(6), 540; https://doi.org/10.3390/insects12060540 - 10 Jun 2021

Cited by 6 | Viewed by 2161

Abstract

Urbanization is increasing worldwide and causes substantial changes in environmental parameters, generating various kinds of stress on arthropods, with several harmful consequences. We examined a forest specialist ground beetle, Carabus convexus, in forested habitats to evaluate the changes in four important life history [...] Read more.

Urbanization is increasing worldwide and causes substantial changes in environmental parameters, generating various kinds of stress on arthropods, with several harmful consequences. We examined a forest specialist ground beetle, Carabus convexus, in forested habitats to evaluate the changes in four important life history traits between rural and urban populations. Analyzing beetles from the overwintered cohort in their first breeding season, we found no significant differences in body length or body mass between the rural and urban individuals. Body condition, judged by fat reserve scores, was similarly poor in both habitats, indicating that beetles were not able to accumulate substantial fat reserves at either habitat. Females with ripe eggs in their ovaries were first captured at the same time in both areas. The number of ripe eggs, however, was significantly higher in females of the low-density urban population (6.13 eggs/female) than in those of the high-density rural population (4.14 eggs/female), indicating density-dependent fecundity. Altered environmental and habitat conditions by urbanization, however, seemed to cause high mortality during egg hatching and/or larval development, preventing the growth of the urban population to the level of rural one. Full article

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

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18 pages, 2229 KiB

Open AccessArticle

Tracing the Origin of Korean Invasive Populations of the Spotted Lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae)

by Hyojoong Kim, Sohee Kim, Yerim Lee, Heung-Sik Lee, Seong-Jin Lee and Jong-Ho Lee

Insects 2021, 12(6), 539; https://doi.org/10.3390/insects12060539 - 10 Jun 2021

Cited by 10 | Viewed by 6795

Abstract

Lycorma delicatula (White) suddenly arrived in Korea where it rapidly spread out in the central region of Korea and caused serious damage to grape vineyards. To trace the source region of its invasiveness, population genetic structures were compared between the native region, China, [...] Read more.

Lycorma delicatula (White) suddenly arrived in Korea where it rapidly spread out in the central region of Korea and caused serious damage to grape vineyards. To trace the source region of its invasiveness, population genetic structures were compared between the native region, China, and the introduced regions, Korea and Japan. We examined 762 individuals from 38 different population collections using 15 microsatellite loci. Both principal coordinate and structure analyses displayed that the Chinese populations were separated into three subgroups which were located significantly far apart from each other. Among them, the Shanghai population was located closest to most Korean populations. Based on the genetic relationships and structures, it was revealed that the multiple introductions into Korea occurred at least three times. In addition, the Shanghai population was strongly estimated to be a source of initial invasive populations of Korea. In addition, analysis of the approximate Bayesian computation suggested simultaneous spread from two distant locations early in the invasion by artificial transportation of the host plants bearing egg masses. Our population genetics study can provide a precedent case with regards to identifying spreads by anthropogenic outcomes in other invasive regions. Full article

(This article belongs to the Collection Biocontrol and Behavioral Approaches to Manage Invasive Insects)

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