Insects

13 pages, 2028 KiB

Open AccessArticle

Organic Control of Pear Psylla in Pear with Trunk Injection

by Celeste E. Wheeler, Christine Vandervoort and John C. Wise

Insects 2020, 11(9), 650; https://doi.org/10.3390/insects11090650 - 22 Sep 2020

Cited by 12 | Viewed by 3643

Organic production of pears is challenging in part because OMRI (Organic Materials Review Institute) approved biopesticides are short lived when applied as foliar sprays. Trunk injection is an alternative method of insecticide delivery that may enhance the performance of biopesticides for control of [...] Read more.

Organic production of pears is challenging in part because OMRI (Organic Materials Review Institute) approved biopesticides are short lived when applied as foliar sprays. Trunk injection is an alternative method of insecticide delivery that may enhance the performance of biopesticides for control of pear psylla. The objective of this study is to compare the efficacy of azadirachtin and abamectin in the control of pear psylla using two different application methods, airblast sprayer and trunk injection. Trunk injections of azadirachtin and abamectin were compared to airblast applications of equal labeled rates on 33-year-old Bartlett Pear trees (Pyrus communis L., var “Bartlett”). The azadirachtin and abamectin trunk injected treatments performed equally or better than the two airblast applications in the control of the pear psylla. The trunk injected trees from the first season provided a moderate level of control into the second season, one year after the injections. This study suggests that trunk injection is a superior delivery system for biopesticides used in organic pear production. Full article

(This article belongs to the Special Issue Organic Pest Management of Invertebrate Pests: A Frontier Borne of Constraints?)

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23 pages, 812 KiB

Open AccessReview

Beyond the Decline of Wild Bees: Optimizing Conservation Measures and Bringing Together the Actors

by Maxime Drossart and Maxence Gérard

Insects 2020, 11(9), 649; https://doi.org/10.3390/insects11090649 - 22 Sep 2020

Cited by 42 | Viewed by 9846

Abstract

Wild bees are facing a global decline mostly induced by numerous human factors for the last decades. In parallel, public interest for their conservation increased considerably, namely through numerous scientific studies relayed in the media. In spite of this broad interest, a lack [...] Read more.

Wild bees are facing a global decline mostly induced by numerous human factors for the last decades. In parallel, public interest for their conservation increased considerably, namely through numerous scientific studies relayed in the media. In spite of this broad interest, a lack of knowledge and understanding of the subject is blatant and reveals a gap between awareness and understanding. While their decline is extensively studied, information on conservation measures is often scattered in the literature. We are now beyond the precautionary principle and experts are calling for effective actions to promote wild bee diversity and the enhancement of environment quality. In this review, we draw a general and up-to-date assessment of the conservation methods, as well as their efficiency and the current projects that try to fill the gaps and optimize the conservation measures. Targeting bees, we focused our attention on (i) the protection and restoration of wild bee habitats, (ii) the conservation measures in anthropogenic habitats, (iii) the implementation of human made tools, (iv) how to deal with invasive alien species, and finally (v) how to communicate efficiently and accurately. This review can be considered as a needed catalyst to implement concrete and qualitative conversation actions for bees. Full article

(This article belongs to the Special Issue Pollinator Conservation)

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17 pages, 1623 KiB

Open AccessArticle

Mixed-Species Gardens Increase Monarch Oviposition without Increasing Top-Down Predation

by Rebecca Nestle, Jaret C. Daniels and Adam G. Dale

Insects 2020, 11(9), 648; https://doi.org/10.3390/insects11090648 - 22 Sep 2020

Cited by 8 | Viewed by 11446

Abstract

Monarch butterfly populations have declined by over 80% in the last 20 years. Conservation efforts focus on the creation of milkweed habitats to mitigate this decline. Previous research has found monarchs lay more eggs per milkweed stem in urban gardens than natural habitats [...] Read more.

Monarch butterfly populations have declined by over 80% in the last 20 years. Conservation efforts focus on the creation of milkweed habitats to mitigate this decline. Previous research has found monarchs lay more eggs per milkweed stem in urban gardens than natural habitats and recent work identified specific garden designs that make urban gardens more attractive to monarchs. Increasing plant diversity can reduce specialist insect herbivore colonization via bottom-up (e.g., plant) and top-down (e.g., predation) regulatory factors. Although this is beneficial for pest management efforts, it contradicts conservation efforts. In this study, we explored if adding multiple flowering species to garden-sized milkweed plantings affected monarch oviposition or top-down regulation of larvae. We compared monarch egg abundance, natural enemy abundance and richness, and biological control of monarch larvae in milkweed monocultures and milkweed mixed with four additional wildflower species. We found that monarchs laid 22% more eggs on sentinel milkweed plants in mixed-species plots with no effect of plant diversity on monarch survival. We also found higher natural enemy richness, wasp, and predatory bug abundance in the mixed-species plots and this did not translate to higher biological control rates. Our results provide more evidence that plant selection and habitat design are important for monarch conservation. Full article

(This article belongs to the Special Issue Pollinator Conservation)

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16 pages, 3746 KiB

Open AccessArticle

Bmapaf-1 is Involved in the Response against BmNPV Infection by the Mitochondrial Apoptosis Pathway

by Xue-yang Wang, Xin-yi Ding, Qian-ying Chen, Kai-xiang Zhang, Chun-xiao Zhao, Xu-dong Tang, Yang-chun Wu and Mu-wang Li

Insects 2020, 11(9), 647; https://doi.org/10.3390/insects11090647 - 22 Sep 2020

Cited by 17 | Viewed by 3073

Abstract

Discovery of the anti-BmNPV (Bombyx mori nuclearpolyhedrovirus) silkworm strain suggests that some kind of antiviral molecular mechanism does exist but is still unclear. Apoptosis, as an innate part of the immune system, plays an important role in the response against pathogen infections [...] Read more.

Discovery of the anti-BmNPV (Bombyx mori nuclearpolyhedrovirus) silkworm strain suggests that some kind of antiviral molecular mechanism does exist but is still unclear. Apoptosis, as an innate part of the immune system, plays an important role in the response against pathogen infections and may be involved in the anti-BmNPV infection. Several candidate genes involved in the mitochondrial apoptosis pathway were identified from our previous study. Bombyx mori apoptosis protease-activating factor-1 (Bmapaf-1) was one of them, but the antiviral mechanism is still unclear. In this study, sequences of BmApaf-1 were characterized. It was found to contain a unique transposase_1 functional domain and share high CARD and NB-ARC domains with other species. Relatively high expression levels of Bmapaf-1 were found at key moments of embryonic development, metamorphosis, and reproductive development. Further, the significant difference in expression of Bmapaf-1 in different tissues following virus infection indicated its close relationship with BmNPV, which was further validated by RNAi and overexpression in BmN cells. Briefly, infection of budded virus with enhanced green fluorescent protein (BV-EGFP) was significantly inhibited at 72 h after overexpression of Bmapaf-1, which was confirmed after knockdown of Bmapaf-1 with siRNA. Moreover, the downstream genes of Bmapaf-1, including Bmnedd2-like caspase (BmNc) and Bmcaspase-1 (Bmcas-1), were upregulated after overexpression of Bmapaf-1 in BmN cells, which was consistent with the RNAi results. Furthermore, the phenomenon of Bmapaf-1 in response to BmNPV infection was determined to be related to apoptosis using the apoptosis inducer NSC348884 and inhibitor Z-DEVD-FMK. Therefore, Bmapaf-1 is involved in the response against BmNPV infection by the mitochondrial apoptosis pathway. This result provides valuable data for clarifying the anti-BmNPV mechanism of silkworms and breeding of resistant silkworm strains. Full article

(This article belongs to the Special Issue Biological Control and Insect Pathology)

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18 pages, 2393 KiB

Open AccessArticle

Beetle Species–Area Relationships and Extinction Rates in Protected Areas

by Simone Fattorini

Insects 2020, 11(9), 646; https://doi.org/10.3390/insects11090646 - 21 Sep 2020

Cited by 15 | Viewed by 3481

Abstract

The species–area relationship (SAR, i.e., the increase in species richness with area) is one of the most general ecological patterns. SARs can be used to calculate expected extinction rates following area (habitat) loss. Here, using data from Italian reserves, extinction rates were calculated [...] Read more.

The species–area relationship (SAR, i.e., the increase in species richness with area) is one of the most general ecological patterns. SARs can be used to calculate expected extinction rates following area (habitat) loss. Here, using data from Italian reserves, extinction rates were calculated for beetle groups with different feeding habits: Carabidae (terrestrial predators), Hydradephaga (aquatic predators), coprophagous Scarabaeoidea (dung feeders), phytophagous Scarabaeoidea (herbivores), and Tenebrionidae (detritivores). The importance of other factors besides area (namely latitude and elevation) was investigated. Reserve area was recovered as an important predictor of species richness in all cases. For Carabidae, Hydradephaga, and Tenebrionidae, elevation exerted a negative influence, whereas latitude had a negative influence on coprophagous Scarabaeoidea and Tenebrionidae, as a consequence of current and historical biogeographical factors. Extinction rates were higher for dung beetles, due to their dependence on large grazing areas, and Tenebrionidae, due to their low dispersal capabilities. The lower extinction rates predicted for Carabidae, phytophagous Scarabaeoidea, and Hydradephaga can be explained by their higher dispersal power. If other variables besides area are considered, extinction rates became more similar among groups. Extinction rates by area loss are always relatively low. Thus, in reserves with few species, many local extinctions might be unnoticed. Full article

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13 pages, 3231 KiB

Open AccessArticle

Diet Breadth Affects Bacterial Identity but Not Diversity in the Pollen Provisions of Closely Related Polylectic and Oligolectic Bees

by Jason A. Rothman, Diana L. Cox-Foster, Corey Andrikopoulos and Quinn S. McFrederick

Insects 2020, 11(9), 645; https://doi.org/10.3390/insects11090645 - 20 Sep 2020

Cited by 12 | Viewed by 3777

Abstract

Mounting evidence suggests that microbes found in the pollen provisions of wild and solitary bees are important drivers of larval development. As these microbes are also known to be transmitted via the environment, most likely from flowers, the diet breadth of a bee [...] Read more.

Mounting evidence suggests that microbes found in the pollen provisions of wild and solitary bees are important drivers of larval development. As these microbes are also known to be transmitted via the environment, most likely from flowers, the diet breadth of a bee may affect the diversity and identity of the microbes that occur in its pollen provisions. Here, we tested the hypothesis that, due to the importance of floral transmission of microbes, diet breadth affects pollen provision microbial community composition. We collected pollen provisions at four sites from the polylectic bee Osmia lignaria and the oligolectic bee Osmia ribifloris. We used high-throughput sequencing of the bacterial 16S rRNA gene to characterize the bacteria found in these provisions. We found minimal overlap in the specific bacterial variants in pollen provisions across the host species, even when the bees were constrained to foraging from the same flowers in cages at one site. Similarly, there was minimal overlap in the specific bacterial variants across sites, even within the same host species. Together, these findings highlight the importance of environmental transmission and host specific sorting influenced by diet breadth for microbes found in pollen provisions. Future studies addressing the functional consequences of this filtering, along with tests for differences between more species of oligoletic and polylectic bees will provide rich insights into the microbial ecology of solitary bees. Full article

(This article belongs to the Collection Bees and Their Symbionts)

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34 pages, 11245 KiB

Open AccessReview

Ecosystem Birth near Melting Glaciers: A Review on the Pioneer Role of Ground-Dwelling Arthropods

by Sigmund Hågvar, Mauro Gobbi, Rüdiger Kaufmann, María Ingimarsdóttir, Marco Caccianiga, Barbara Valle, Paolo Pantini, Pietro Paolo Fanciulli and Amber Vater

Insects 2020, 11(9), 644; https://doi.org/10.3390/insects11090644 - 19 Sep 2020

Cited by 33 | Viewed by 6218

Abstract

As glaciers retreat, their forelands represent “natural laboratories” for the study of primary succession. This review describes how certain arthropods conquer pristine ground and develop food webs before the establishment of vascular plants. Based on soil samples, pitfall traps, fallout and sticky traps, [...] Read more.

As glaciers retreat, their forelands represent “natural laboratories” for the study of primary succession. This review describes how certain arthropods conquer pristine ground and develop food webs before the establishment of vascular plants. Based on soil samples, pitfall traps, fallout and sticky traps, gut content studies, and some unpublished data, we compare early arthropod succession on glacial forelands of northern Europe (Iceland, Norway including Svalbard, and Sweden) and of the Alps (Austria, Italy). While macroarthropod predators like ground beetles (Coleoptera: Carabidae), harvestmen (Arachnida: Opiliones), and spiders (Arachnida: Araneae) have usually been considered as pioneers, assumed to feed on airborne prey, this review explains a different pattern. Here, we highlight that springtails (Collembola), probably feeding on biofilm made up of algae or cyanobacteria, are super-pioneers, even at high altitudes and under arctic conditions. We also point out that macroarthropod predators can use locally available prey, such as springtails or non-biting midges (Diptera: Chironomidae). Pioneer arthropod communities vary under different biogeographical and climatic conditions. Two pioneer food webs, from northern Europe and the Alps, respectively, differed in structure and function. However, certain genera and orders were common to both. Generalists and specialists live together in a pioneer community. Cold-adapted specialists are threatened by glacier melting. Full article

(This article belongs to the Collection Insects in Mountain Ecosystems)

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7 pages, 1324 KiB

Open AccessBrief Report

Cannibalism in the Brown Marmorated Stink Bug Halyomorpha halys (Stål)

by Giulia Papa and Ilaria Negri

Insects 2020, 11(9), 643; https://doi.org/10.3390/insects11090643 - 19 Sep 2020

Cited by 4 | Viewed by 3745

Abstract

The phytophagous brown marmorated stink bug Halyomorpha halys (Stål) is known to exhibit cannibalistic behaviour towards eggs. Here, we provide evidence of cannibalism among overwintering H. halys adults. Since diapausing individuals have high physiological demands for surviving long periods under stressful conditions, including [...] Read more.

The phytophagous brown marmorated stink bug Halyomorpha halys (Stål) is known to exhibit cannibalistic behaviour towards eggs. Here, we provide evidence of cannibalism among overwintering H. halys adults. Since diapausing individuals have high physiological demands for surviving long periods under stressful conditions, including the risk of depletion of metabolic reserves and desiccation, we assumed that nutritional and water requirements can be met by intraspecific predation. The role of aggregative behaviour in promoting cannibalism is also discussed. Given its evolutionary advantage, this trait should be maintained over generations and may be more widespread than previously considered in species that display aggregative behaviour during adverse seasons. Full article

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13 pages, 3191 KiB

Open AccessArticle

NADPH Oxidase 5 Is Essential for Molting and Oviposition in a Rice Planthopper Nilaparvata lugens

by Lu-Yao Peng, Zhen-Wei Dai, Rui-Rui Yang, Zhen Zhu, Wei Wang, Xiang Zhou and Yan-Yuan Bao

Insects 2020, 11(9), 642; https://doi.org/10.3390/insects11090642 - 18 Sep 2020

Cited by 6 | Viewed by 3312

Abstract

The brown planthopper Nilaparvata lugens is a typical monophagous insect herbivore that feeds exclusively on rice sap. This insect pest causes serious damage to rice crops throughout East Asian countries. Chemical control remains the first choice for managing N. lugens populations; however, the [...] Read more.

The brown planthopper Nilaparvata lugens is a typical monophagous insect herbivore that feeds exclusively on rice sap. This insect pest causes serious damage to rice crops throughout East Asian countries. Chemical control remains the first choice for managing N. lugens populations; however, the use of insecticides has given rise to planthopper resurgence and additional environmental risks. Nilaparvata lugens is a model insect of Hemiptera because its whole genome sequence has been elucidated and is susceptible to RNA interference. In this study, our findings revealed that a superoxide-generating gene, NADPH oxidase 5 (Nox5), is essential for molting and oviposition in a Hemipteran insect Nilaparvata lugens. Knockdown of Nox5 transcript levels by RNA interference in 2nd–5th-instar nymphs results in significantly lethal deficits in the molting transitions from nymph–nymph and nymph–adult. Nox5 knockdown leads to a reduction of hydrogen peroxide in female ovaries and failure of oviposition from the insect ovipositor into the rice leaf sheath. Here, we provide in vivo evidence demonstrating that Nox5 is a key enzyme for regulating molting and oviposition in this insect species. Full article

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20 pages, 3434 KiB

Open AccessArticle

Endemics Versus Newcomers: The Ladybird Beetle (Coleoptera: Coccinellidae) Fauna of Gran Canaria

by Jerzy Romanowski, Piotr Ceryngier, Jaroslav Vĕtrovec, Marta Piotrowska and Karol Szawaryn

Insects 2020, 11(9), 641; https://doi.org/10.3390/insects11090641 - 18 Sep 2020

Cited by 9 | Viewed by 3764

Abstract

Research on the fauna of beetles (Coleoptera) of the Canary Islands has a long tradition, which enables tracking changes in their species composition and arrival of new species. In this paper, we provide new faunistic data on the ladybird beetles (Coccinellidae) recorded on [...] Read more.

Research on the fauna of beetles (Coleoptera) of the Canary Islands has a long tradition, which enables tracking changes in their species composition and arrival of new species. In this paper, we provide new faunistic data on the ladybird beetles (Coccinellidae) recorded on Gran Canaria, one of the central islands of the archipelago, and then analyze available information on the Gran Canarian ladybird fauna from geographical and historical points of view. The field survey resulted in recording 1402 ladybird individuals belonging to 30 species. Ten of these species were new to Gran Canaria and three of them, Chilocorus bipustulatus (Linnaeus), Nephus bisignatus (Boheman), and Nephus ulbrichi Fürsch, had not previously been reported to be on any of the islands of the Canarian archipelago. Tetrabrachys tinerfensis (Hodgson) is synonymized with T. deserticola (Wollaston). Our survey and literature reports allowed us to recognize 42 species of Coccinellidae so far recorded on Gran Canaria. Seventeen of them (40%) belonged to the Canarian endemic and subendemic species, and 21 (50%) were newcomers and presumed newcomers. Colonization of Gran Canaria and other islands of the archipelago by ladybird species of various origins seems to be a frequent phenomenon that may pose a threat to the unique communities of the native Canarian species. Full article

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17 pages, 3337 KiB

Open AccessArticle

Influences of Exposure Time and Mortality Assessment Interval on Bioassay Results of Insecticide-Resistant Tropical Bed Bugs (Hemiptera: Cimicidae)

by Xin-Yeng Leong, G. Veera Singham, Alexander Chong Shu-Chien, Stephen L. Doggett and Chow-Yang Lee

Insects 2020, 11(9), 640; https://doi.org/10.3390/insects11090640 - 18 Sep 2020

Cited by 8 | Viewed by 2957

Abstract

We evaluated the influences of insecticide exposure time and mortality assessment intervals on the bioassay results of three insecticide-resistant tropical bed bug Cimex hemipterus (F.) populations (Madam Mo, Tanjong Tokong, and Green Lane). This was achieved using the surface contact method and tested [...] Read more.

We evaluated the influences of insecticide exposure time and mortality assessment intervals on the bioassay results of three insecticide-resistant tropical bed bug Cimex hemipterus (F.) populations (Madam Mo, Tanjong Tokong, and Green Lane). This was achieved using the surface contact method and tested with six commercial insecticide products: Tandem, Temprid SC, Pesguard FG161, Sumithrin, Sumithion, and Phantom applied at label rate on glass petri dishes. Six exposure times (5 min, 10 min, 30 min, 1 h, 4 h, and continuous exposure for 4 or 14 days for Phantom) were tested. A susceptible common bed bug Cimex lectularius L. strain (Monheim) was used as the reference strain as no susceptible C. hemipterus strain exists. In treatment with Temprid SC, the Tanjong Tokong strain showed significantly higher KT₅₀ values at 5, 10, and 30 min exposures than 1 h, 4 h, and continuous exposures. When all resistant populations were evaluated at continuous exposure to Sumithion, they demonstrated moderate resistance levels (RR₅₀ ranged from 6.0 to 7.9), while KT₅₀ and KT₉₅ of other shorter exposure times failed to be generated due to low knockdown rate. Higher mortalities were observed in Tanjong Tokong and Green Lane strains when tested at longer exposure times with Temprid SC, Pesguard FG161, Sumithrin, Sumithion, and Phantom. Better killing effect was observed in the treatment with Temprid SC (Tanjong Tokong and Green Lane strains), Pesguard FG161 (Tanjong Tokong and Green Lane strains), Sumithrin (all C. hemipterus strains), Sumithion (all C. hemipterus strains), and Phantom (all strains tested) at longer mortality assessment intervals. We demonstrated that insecticide exposure time and mortality assessment interval could potentially affect outcomes of product performance evaluations, resulting in underestimation or overestimation of insecticide resistance levels in field populations. Full article

(This article belongs to the Special Issue Biology and Management of Bed Bugs)

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14 pages, 2690 KiB

Open AccessArticle

The Population Growth of Spodoptera frugiperda on Six Cash Crop Species and Implications for Its Occurrence and Damage Potential in China

by Wenwen Wang, Pengyang He, Yiyang Zhang, Tongxian Liu, Xiangfeng Jing and Shize Zhang

Insects 2020, 11(9), 639; https://doi.org/10.3390/insects11090639 - 17 Sep 2020

Cited by 54 | Viewed by 4550

Abstract

Spodoptera frugiperda is a significant migratory invasive pest, identified as a serious threat to agricultural production and food security in China. However, to our knowledge, the effects of most host plants on the biological characteristics of S. frugiperda have not been well studied. [...] Read more.

Spodoptera frugiperda is a significant migratory invasive pest, identified as a serious threat to agricultural production and food security in China. However, to our knowledge, the effects of most host plants on the biological characteristics of S. frugiperda have not been well studied. To develop effective management strategies for S. frugiperda in its new invasive habitat, basic biological and ecological knowledge of this pest are crucial requirements. Here, we examined the effects of six cash crops maize, wheat, soybean, tomato, cotton and Chinese cabbage on the development, survival, fecundity of S. frugiperda by using the age-stage, two-sex life table. The preadult stage, adult preoviposition period and total preoviposition period of S. frugiperda were shortest on maize and wheat but were longest on tomato. Fecundity was greatest on maize and wheat but smallest on tomato. The highest intrinsic rate of increase, finite rate of increase, net reproductive rate and the shortest mean generation time were recorded on maize. This present study showed that S. frugiperda could cause great economic losses to these cash crops, which should attract the attention of agricultural management departments. Our findings provide useful information in predicting population dynamics and understanding the potential damage that could be incurred by S. frugiperda invasion. Full article

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16 pages, 1994 KiB

Open AccessArticle

Effects on Some Therapeutical, Biochemical, and Immunological Parameters of Honey Bee (Apis mellifera) Exposed to Probiotic Treatments, in Field and Laboratory Conditions

by Ivana Tlak Gajger, Josipa Vlainić, Petra Šoštarić, Janez Prešern, Jernej Bubnič and Maja Ivana Smodiš Škerl

Insects 2020, 11(9), 638; https://doi.org/10.3390/insects11090638 - 17 Sep 2020

Cited by 32 | Viewed by 8807

Abstract

Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM^® for bees could potentially have an important therapeutic and immunomodulatory effect on honey bee colonies. The aim of [...] Read more.

Several negative factors contribute to a decline in the number of insect pollinators. As a novel approach in therapy, we hypothesize that the EM^® for bees could potentially have an important therapeutic and immunomodulatory effect on honey bee colonies. The aim of our study was to evaluate its impact on honey bees at the individual and colony level. This is the first appliance of the commercial probiotic mix EM^® PROBIOTIC FOR BEES in honey bees as economically important social insects. The sugar syrup with 10% of probiotic was administered by spraying or feeding the honey bee colonies in the field conditions, in order to evaluate the infection levels with spores of Nosema spp. and colonies’ strength. Moreover, in laboratory-controlled conditions, in the hoarding cages, adult workers have been fed with sugar syrup supplemented with 2.5, 5, and 10% of EM^® for bees for biochemical and immunological analyses of hemolymph, and with 5 and 10% for measuring the size of hypopharyngeal glands. It was found that following the EM^® for bees administration the Nosema spp. spore counts in colonies were significantly reduced, and colonies’ strength was increased. The results at the individual level showed significant positive physiological changes in treated groups of adult bees, revealing at the same time a higher mortality rate when feeding sugar syrup supplemented with the probiotic. Full article

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12 pages, 941 KiB

Open AccessArticle

Molecular Assessment of Genes Linked to Immune Response Traits of Honey Bees in Conventional and Organically Managed Apiaries

by Shalom C. Siebert, Lambert H. B. Kanga, Sheikh M. Basha and Jesusa C. Legaspi

Insects 2020, 11(9), 637; https://doi.org/10.3390/insects11090637 - 17 Sep 2020

Cited by 1 | Viewed by 2776

Abstract

Honey bees are of great economic importance, not only for honey production but also for crop pollination. However, honey bee populations continue to decline mainly due to exposure to pesticides, pathogens and beekeeping practices. In this study, total soluble protein was measured, total [...] Read more.

Honey bees are of great economic importance, not only for honey production but also for crop pollination. However, honey bee populations continue to decline mainly due to exposure to pesticides, pathogens and beekeeping practices. In this study, total soluble protein was measured, total RNA was extracted and first-strand cDNAs were generated. Quantitative PCR was used to assess the relative expression (transcript abundances) of immune function-related genes in honey bees collected from organically and conventionally managed hives. Honey bees collected from conventionally managed hives with 0% Varroa mite infestation levels displayed an upregulated expression of the prophenoloxidase gene (cellular defense). Similarly, honey bees collected from organically managed hives had increased levels of the vitellogenin gene (immune function and longevity). The gene expression for malvolio (sucrose responsiveness) was highest in organically managed hives with 0% Varroa mite infestations. Young adult bees collected from organically managed hives with 5% Varroa mite infestation levels had upregulated expressions of the gene spaetzle, whereas bees from similarly infested, conventionally managed hives did not, suggesting that honey bees from organically managed hives could mount an immune response. In young adult bees collected from organically managed hives only, the expression of the immune deficiency gene (antimicrobial defense) was upregulated. The relative gene expression for superoxide dismutase 1 increased in young adult bees collected from hives with 5% Varroa mite infestation levels as expected. However, for superoxide dismutase 2, there was a high level of gene expression in adult bees from both conventionally managed hives with 0% Varroa mite infestation levels and organically managed hives with 5% Varroa mite infestations. The gene CYP9Q3 (pesticide detoxification) that metabolizes coumaphos and fluvalinate was upregulated in adult bees collected from organically managed bees. Overall, these findings provide useful insights into the genetic response of honey bees to some environmental stressors and could be an important component of best beekeeping practices that intend to enhance honey bee health. Full article

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10 pages, 482 KiB

Open AccessArticle

The First Record of Monochamus saltuarius (Coleoptera; Cerambycidae) as Vector of Bursaphelenchus xylophilus and Its New Potential Hosts in China

by Min Li, Huan Li, Ruo-Cheng Sheng, Hui Sun, Shou-Hui Sun and Feng-Mao Chen

Insects 2020, 11(9), 636; https://doi.org/10.3390/insects11090636 - 16 Sep 2020

Cited by 39 | Viewed by 3297

Abstract

Pine wilt disease was first discovered in Dongtang town, Liaoning Province, China, in 2017. However, no record of Monochamus alteratus existed in Fengcheng, where M. saltuarius is an indigenous insect, and no experimental evidence has thus far indicated that M. saltuarius can transport [...] Read more.

Pine wilt disease was first discovered in Dongtang town, Liaoning Province, China, in 2017. However, no record of Monochamus alteratus existed in Fengcheng, where M. saltuarius is an indigenous insect, and no experimental evidence has thus far indicated that M. saltuarius can transport the Bursaphelenchus xylophilus in China. In this study, we investigated whether M. saltuarius is a vector of B. xylophilus in China. On the sixth day after eclosion, beetles began to transmit nematodes into the twigs. The transmission period of nematodes is known to be able to last for 48 days after beetle emergence. In laboratory experiments, M. saltuarius fed and transmitted B. xylophilus not only on pines but also on other non-Pinus conifers. The non-Pinus conifers preferred by M. saltuarius for feeding are Picea pungens, Picea asperata, and Abies fabri. The experimental results show that M. saltuarius functions as a vector of B. xylophilus in northeast China. Full article

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20 pages, 3292 KiB

Open AccessArticle

Development of a Mating Disruption Program for a Mealybug, Planococcus ficus, in Vineyards

by Kent M. Daane, Glenn Y. Yokota, Vaughn M. Walton, Brian N. Hogg, Monica L. Cooper, Walter J. Bentley and Jocelyn G. Millar

Insects 2020, 11(9), 635; https://doi.org/10.3390/insects11090635 - 16 Sep 2020

Cited by 18 | Viewed by 4255

Abstract

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards, and improvements in sustainable control of this pest are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption. In a series [...] Read more.

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards, and improvements in sustainable control of this pest are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption. In a series of experiments conducted from 2004 to 2007, we tested the effects of mating disruption on trap captures of Pl. ficus males in pheromone-baited traps, on Pl. ficus numbers and age structure on vines, and on damage to grape clusters. From 2004 to 2005, the effects of dispenser load (mg active ingredient per dispenser) were also assessed, and dispensers were compared to a flowable formulation. Across all trials, mating disruption consistently reduced pheromone trap captures and often reduced mealybug numbers on vines and/or crop damage, regardless of the pheromone dose that was applied. Reductions in Pl. ficus densities in mating disruption plots were not accompanied by clear effects on mealybug population age structure; however, production of non-viable ovisacs by unmated females may have obscured differences in proportional representation of ovisacs. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high Pl. ficus densities. Trap-capture patterns in both treated and control plots commonly began low in April–May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. During the four-year trial, the release rate from plastic sachet dispensers was improved by industry cooperators as pheromone was released too quickly (2004) or not completely released during the season (2005–2006). The flowable formulation performed slightly better than dispensers at the same application dose. Results over all years suggest season-long coverage or late-season coverage may be as or more important than dose per hectare. Development of a dispenser with optimized season-long pheromone emission or targeted seasonal periods should be a future goal. Full article

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11 pages, 1595 KiB

Open AccessArticle

Diversity and Regulation of S-Adenosylmethionine Dependent Methyltransferases in the Anhydrobiotic Midge

by Ruslan Deviatiiarov, Rustam Ayupov, Alexander Laikov, Elena Shagimardanova, Takahiro Kikawada and Oleg Gusev

Insects 2020, 11(9), 634; https://doi.org/10.3390/insects11090634 - 16 Sep 2020

Cited by 4 | Viewed by 3155

Abstract

Multiple co-localized paralogs of genes in Polypedilum vanderplanki’s genome have strong transcriptional response to dehydration and considered to be a part of adaptation machinery at the larvae stage. One group of such genes represented by L-isoaspartate O-methyltransferases (PIMT). In order to highlight specific [...] Read more.

Multiple co-localized paralogs of genes in Polypedilum vanderplanki’s genome have strong transcriptional response to dehydration and considered to be a part of adaptation machinery at the larvae stage. One group of such genes represented by L-isoaspartate O-methyltransferases (PIMT). In order to highlight specific role of PIMT paralogization in desiccation tolerance of the larvae we annotated and compared S-adenosylmethionine (SAM) dependent methyltransferases of four insect species. From another side we applied co-expression analysis in desiccation/rehydration time course and showed that PIMT coding genes could be separated into five clusters by expression profile. We found that among Polypedilum vanderplanki’s PIMTs only PIMT1 and PIMT2 have enzymatic activity in normal physiological conditions. From in silico analysis of the protein structures we found two highly variable regions outside of the active center, but also amino acid substitutions which may affect SAM stabilization. Overall, in this study we demonstrated features of Polypedilum vanderplanki’s PIMT coding paralogs related to different roles in desiccation tolerance of the larvae. Our results also suggest a role of different SAM-methyltransferases in the adaptation, including GSMT, JHAMT, and candidates from other classes, which could be considered in future studies. Full article

(This article belongs to the Special Issue The Adaptations of Arthropods to Extreme Environments)

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13 pages, 1195 KiB

Open AccessArticle

Potato Tuberworm Phthorimaea operculella (Zeller) (Lepidoptera: Gelechioidea) Leaf Infestation Affects Performance of Conspecific Larvae on Harvested Tubers by Inducing Chemical Defenses

by Dingli Wang, Qiyun Wang, Xiao Sun, Yulin Gao and Jianqing Ding

Insects 2020, 11(9), 633; https://doi.org/10.3390/insects11090633 - 15 Sep 2020

Cited by 7 | Viewed by 2851

Abstract

Conspecific aboveground and belowground herbivores can interact with each other, mediated by plant secondary chemicals; however, little attention has been paid to the interaction between leaf feeders and tuber-feeders. Here, we evaluated the effect of the foliar feeding of P. operculella larvae on [...] Read more.

Conspecific aboveground and belowground herbivores can interact with each other, mediated by plant secondary chemicals; however, little attention has been paid to the interaction between leaf feeders and tuber-feeders. Here, we evaluated the effect of the foliar feeding of P. operculella larvae on the development of conspecific larvae feeding on harvested tubers by determining the nutrition and defense metabolites in the whole plant (leaf, root and tuber). We found that leaf feeding negatively affected tuber larval performance by increasing the female larval developmental time and reducing the male pupal weight. In addition, aboveground herbivory increased α-chaconine and glycoalkaloids in tubers and α-solanine in leaves, but decreased α-chaconine and glycoalkaloids in leaves. Aboveground herbivory also altered the levels of soluble sugar, soluble protein, starch, carbon (C), nitrogen (N), as well as the C:N ratio in both leaves and tubers. Aboveground P. operculella infestations could affect the performance of conspecific larvae feeding on harvested tubers by inducing glycoalkaloids in the host plant. Our findings indicate that field leaf herbivory should be considered when assessing the quality of potato tubers and their responses to pests during storage. Full article

(This article belongs to the Collection Integrated Pest Management in Arable and Open Field Horticultural Crops)

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16 pages, 2010 KiB

Open AccessArticle

Water Costs of Gas Exchange by a Speckled Cockroach and a Darkling Beetle

by Waseem Abbas, Philip C. Withers and Theodore A. Evans

Insects 2020, 11(9), 632; https://doi.org/10.3390/insects11090632 - 14 Sep 2020

Cited by 2 | Viewed by 3656

Abstract

Respiratory water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. It has been suggested to depend on several factors, such as the mode of gas exchange (convective vs. diffusive), species habitat (aridity), body size and measurement conditions [...] Read more.

Respiratory water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. It has been suggested to depend on several factors, such as the mode of gas exchange (convective vs. diffusive), species habitat (aridity), body size and measurement conditions (temperature). We measured this cost in terms of respiratory water loss relative to metabolic rate (respiratory water cost of gas exchange; RWL/

{\dot{V}}_{C O_{2}}

) for adults of two insect species, the speckled cockroach (Nauphoeta cinerea) and the darkling beetle (Zophobas morio), which are similar in their mode of gas exchange (dominantly convective), habitat (mesic), body size and measurement conditions, by measuring gas exchange patterns using flow-through respirometry. The speckled cockroaches showed both continuous and discontinuous gas exchange patterns, which had significantly a different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This outcome from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful index of environmental adaptation (e.g., aridity) than just the respiratory water cost. Full article

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14 pages, 2967 KiB

Open AccessArticle

De Novo Transcriptomic and Metabolomic Analyses Reveal the Ecological Adaptation of High-Altitude Bombus pyrosoma

by Yanjie Liu, Huiyue Zhao, Qihua Luo, Yadong Yang, Guangshuo Zhang, Zhiyong Zhou, Muhammad Naeem and Jiandong An

Insects 2020, 11(9), 631; https://doi.org/10.3390/insects11090631 - 14 Sep 2020

Cited by 11 | Viewed by 3393

Abstract

Bombus pyrosoma is one of the most abundant bumblebee species in China, with a distribution range of very varied geomorphology and vegetation, which makes it an ideal pollinator species for research into high-altitude adaptation. Here, we sequenced and assembled transcriptomes of B. pyrosoma [...] Read more.

Bombus pyrosoma is one of the most abundant bumblebee species in China, with a distribution range of very varied geomorphology and vegetation, which makes it an ideal pollinator species for research into high-altitude adaptation. Here, we sequenced and assembled transcriptomes of B. pyrosoma from the low-altitude North China Plain and the high-altitude Tibet Plateau. Subsequent comparative analysis of de novo transcriptomes from the high- and low-altitude groups identified 675 common upregulated genes (DEGs) in the high-altitude B. pyrosoma. These genes were enriched in metabolic pathways and corresponded to enzyme activities involved in energy metabolism. Furthermore, according to joint analysis with comparative metabolomics, we suggest that the metabolism of coenzyme A (CoA) and the metabolism and transport of energy resources contribute to the adaptation of high-altitude B. pyrosoma. Meanwhile, we found many common upregulated genes enriched in the Toll and immune deficiency (Imd)signaling pathways that act as important immune defenses in insects, and hypoxia and cold temperatures could induce the upregulation of immune genes in insects. Therefore, we suppose that the Toll and Imd signaling pathways also participated in the high-altitude adaptation of B. pyrosoma. Like other organisms, we suggest that the high-altitude adaptation of B. pyrosoma is controlled by diverse mechanisms. Full article

(This article belongs to the Special Issue The Adaptations of Arthropods to Extreme Environments)

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14 pages, 883 KiB

Open AccessArticle

Compatibility between Entomopathogenic Fungi and Egg Parasitoids (Trichogrammatidae): A Laboratory Study for Their Combined Use to Control Duponchelia fovealis

by Emily Silva Araujo, Alex S. Poltronieri, Carolina G. Poitevin, José Manuel Mirás-Avalos, Maria Aparecida Cassilha Zawadneak and Ida Chapaval Pimentel

Insects 2020, 11(9), 630; https://doi.org/10.3390/insects11090630 - 14 Sep 2020

Cited by 16 | Viewed by 3460

Abstract

The European pepper moth, Duponchelia fovealis (Lepidoptera: Crambidae), is a key pest in strawberry production. Entomopathogenic fungi (EF) and parasitoids of the Trichogrammatidae family are effective biological control agents of this pest with the potential to be used jointly for improved efficacy. This [...] Read more.

The European pepper moth, Duponchelia fovealis (Lepidoptera: Crambidae), is a key pest in strawberry production. Entomopathogenic fungi (EF) and parasitoids of the Trichogrammatidae family are effective biological control agents of this pest with the potential to be used jointly for improved efficacy. This study aims to evaluate the susceptibility of Trichogramma atopovirilia and Trichogramma pretiosum to two Beauveria bassiana strains (B2 and B3) and two commercial bioinsecticides (Bovemax^® and Methamax^®) by applying them to D. fovealis eggs in pre- and post-parasitism periods. Pre-parasitism application of B2 and B3 did not affect the percentage of D. fovealis eggs parasitized by either Trichogramma species, except in the case of T. atopovirilia when eggs were sprayed with B3 at 1.5 × 10⁵ conidia mL⁻¹ (16.7% less than the control). In contrast, eggs sprayed with 1.5 × 10⁸ conidia mL⁻¹ of the commercial bioinsecticides were not parasitized by any Trichogramma species. Overall, the EF tested reduced the parasitism rate, adult emergence, and longevity of Trichogramma adults by less than 30% in all cases. The adverse effects of the B. bassiana strains and commercial products on the biological traits of both Trichogramma species were minimal, meaning that these agents can be used jointly in D. fovealis control strategies. Full article

(This article belongs to the Collection Natural Enemies and Biological Control of Plant Pests)

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15 pages, 2093 KiB

Open AccessArticle

Diapause Regulation in Newly Invaded Environments: Termination Timing Allows Matching Novel Climatic Constraints in the Box Tree Moth, Cydalima perspectalis (Lepidoptera: Crambidae)

by Laura Poitou, Audrey Bras, Patrick Pineau, Philippe Lorme, Alain Roques, Jérôme Rousselet, Marie-Anne Auger-Rozenberg and Mathieu Laparie

Insects 2020, 11(9), 629; https://doi.org/10.3390/insects11090629 - 12 Sep 2020

Cited by 9 | Viewed by 3279

Abstract

The association between indirect environmental cues that modulate insect diapause and the actual stressors is by no means granted when a species encounters new environments. The box tree moth, Cydalima perspectalis, is an Asian pest whose rapid invasion in Europe causes considerable [...] Read more.

The association between indirect environmental cues that modulate insect diapause and the actual stressors is by no means granted when a species encounters new environments. The box tree moth, Cydalima perspectalis, is an Asian pest whose rapid invasion in Europe causes considerable economic and ecological impacts. Larvae enter a winter diapause induced by the photoperiod in both native and invaded ranges, but factors that trigger the return to an active phase are still unknown. Yet, identifying them is crucial to understand how diapause end synchronizes with the end of the winter stress encountered in Europe. To test whether activity resumption is regulated by thermal and/or photoperiodic thresholds, or additive effects between these factors often involved in diapause termination, diapausing caterpillars from an invaded area were exposed to crossed treatments at the laboratory. The evolution of diapause rate was monitored over time and compared to that of nearby field sites invaded. A strong positive effect of increasing temperature was found on the rate and dynamics of diapause termination, whereas no compelling effect of photoperiod appeared. Resuming development directly when main stressors fade, not in response to indirect photoperiodic cues that could be mismatched outside native areas, likely contributes to the good match observed between diapause and the new climates that this pest encountered in the invaded range. Full article

(This article belongs to the Special Issue Effects of Environmental Stress on Insects)

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8 pages, 2088 KiB

Open AccessCommunication

Plagues of Desert Locusts: Very Low Invasion Risk to China

by Yun-Ping Wang, Ming-Fei Wu, Pei-Jiong Lin, Yao Wang, Ai-Dong Chen, Yu-Ying Jiang, Bao-Ping Zhai, Jason W. Chapman and Gao Hu

Insects 2020, 11(9), 628; https://doi.org/10.3390/insects11090628 - 11 Sep 2020

Cited by 15 | Viewed by 3688

Abstract

Recently, the most serious upsurge of the desert locust (Schistocerca gregaria) in the last 25 years is spreading across eastern Africa and southwestern Asia. Parts of the desert locust ‘invasion area’, namely the northern border areas of Pakistan and India, are [...] Read more.

Recently, the most serious upsurge of the desert locust (Schistocerca gregaria) in the last 25 years is spreading across eastern Africa and southwestern Asia. Parts of the desert locust ‘invasion area’, namely the northern border areas of Pakistan and India, are very close to China, and whether locust swarms will invade China is of wide concern. To answer this question, we identified areas of potentially suitable habitat for the desert locust within China based on historical precipitation and temperature data, and found that parts of Xinjiang and Inner Mongolia provinces could provide ephemeral habitat in summer, but these places are remote from any other desert locust breeding areas. New generation adults of the desert locust in Pakistan and India present since April led to swarms spreading into the Indo-Pakistan border region in June, and so we examined historical wind data for this period. Our results showed that winds at the altitude of locust swarm flight blew eastward during April–June, but the wind speeds were quite slow and would not facilitate desert locust eastward migration over large distances. Simulated trajectories of desert locust swarms undertaking 10-day migrations mostly ended within India. The most easterly point of these trajectories just reached eastern India, and this is very close to the eastern border of the invasion area of desert locusts described in previous studies. Overall, the risk that the desert locust will invade China is very low. Full article

(This article belongs to the Special Issue Locusts and Grasshoppers: Biology, Ecology and Management)

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18 pages, 7701 KiB

Open AccessArticle

Tracking Red Palm Mite Damage in the Western Hemisphere Invasion with Landsat Remote Sensing Data

by Jose Carlos Verle Rodrigues, Michael H. Cosh, E. Raymond Hunt, Jr., Gilberto J. de Moraes, Geovanny Barroso, William A. White and Ronald Ochoa

Insects 2020, 11(9), 627; https://doi.org/10.3390/insects11090627 - 11 Sep 2020

Cited by 3 | Viewed by 16154

Abstract

Red palm mites (Raoiella indica Hirst, Acari: Tenuipalpidae) were first observed in the western hemisphere on the islands and countries surrounding the Caribbean Sea, infesting the coconut palm (Cocos nucifera L.). Detection of invasive pests usually relies upon changes in vegetation [...] Read more.

Red palm mites (Raoiella indica Hirst, Acari: Tenuipalpidae) were first observed in the western hemisphere on the islands and countries surrounding the Caribbean Sea, infesting the coconut palm (Cocos nucifera L.). Detection of invasive pests usually relies upon changes in vegetation properties as result of the pest activity. These changes may be visible in time series of satellite data records, such as Landsat satellites, which have been available with a 16-day repeat cycle at a spatial resolution of 30 m since 1982. Typical red palm mite infestations result in the yellowing of the lower leaves of the palm crown; remote sensing model simulations have indicated that this feature may be better detected using the green normalized difference vegetation index (GNDVI). Using the Google Earth Engine programming environment, a time series of Landsat 5 Thematic Mapper, Landsat 7 Enhanced Thematic Mapper Plus and Landsat 8 Operational Land Imager data was generated for plantations in northern and northeast Brazil, El Salvador, and Trinidad-Tobago. Considering the available studied plantations, there were little or no differences of GNDVI before and after the dates when red palm mites were first revealed at each location. A discussion of possible alternative approaches are discussed related to the limitations of the current satellite platforms. Full article

(This article belongs to the Special Issue Invasive Arthropod Pests)

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17 pages, 1933 KiB

Open AccessArticle

Divergence of Desiccation-Related Traits in Sitobion avenae from Northwestern China

by Yujing Yang, Deguang Liu, Xiaoming Liu, Biyao Wang and Xiaoqin Shi

Insects 2020, 11(9), 626; https://doi.org/10.3390/insects11090626 - 11 Sep 2020

Cited by 3 | Viewed by 2494

Abstract

The impact of drought on insects has become increasingly evident in the context of global climate change, but the physiological mechanisms of aphids’ responses to desiccating environments are still not well understood. We sampled the wheat aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) from [...] Read more.

The impact of drought on insects has become increasingly evident in the context of global climate change, but the physiological mechanisms of aphids’ responses to desiccating environments are still not well understood. We sampled the wheat aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae) from arid areas of northwestern China. Both desiccation-resistant and -nonresistant genotypes were identified, providing direct evidence of genetic divergence in desiccation resistance of S. avenae. Resistant genotypes of wingless S. avenae showed longer survival time and LT50 under the desiccation stress (i.e., 10% relative humidity) than nonresistant genotypes, and wingless individuals tended to have higher desiccation resistance than winged ones. Both absolute and relative water contents did not differ between the two kinds of genotypes. Resistant genotypes had lower water loss rates than nonresistant genotypes for both winged and wingless individuals, suggesting that modulation of water loss rates could be the primary strategy in resistance of this aphid against desiccation stress. Contents of cuticular hydrocarbons (CHC) (especially methyl-branched alkanes) showed significant increase for both resistant and nonresistant genotypes after exposure to the desiccation stress for 24 h. Under desiccation stress, survival time was positively correlated with contents of methyl-branched alkanes for resistant genotypes. Thus, the content of methyl-branched alkanes and their high plasticity could be closely linked to water loss rate and desiccation resistance in S. avenae. Our results provide insights into fundamental aspects and underlying mechanisms of desiccation resistance in aphids, and have significant implications for the evolution of aphid populations in the context of global warming. Full article

(This article belongs to the Special Issue The Adaptations of Arthropods to Extreme Environments)

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11 pages, 1663 KiB

Open AccessArticle

Phylogeny and Density Dynamics of Wolbachia Infection of the Health Pest Paederus fuscipes Curtis (Coleoptera: Staphylinidae)

by Chen Ge, Jiayao Hu, Zimiao Zhao, Ary A. Hoffmann, Shuojia Ma, Li Shen, Jie Fang, Jianqing Zhu, Weidong Yu and Weibin Jiang

Insects 2020, 11(9), 625; https://doi.org/10.3390/insects11090625 - 11 Sep 2020

Cited by 10 | Viewed by 3396

Abstract

The maternally inherited obligate intracellular bacteria Wolbachia infects the reproductive tissues of a wide range of arthropods and affects host reproduction. Wolbachia is a credible biocontrol agent for reducing the impact of diseases associated with arthropod vectors. Paederus fuscipes is a small staphylinid [...] Read more.

The maternally inherited obligate intracellular bacteria Wolbachia infects the reproductive tissues of a wide range of arthropods and affects host reproduction. Wolbachia is a credible biocontrol agent for reducing the impact of diseases associated with arthropod vectors. Paederus fuscipes is a small staphylinid beetle that causes dermatitis linearis and conjunctivitis in humans when they come into contact with skin. Wolbachia occur in this beetle, but their relatedness to other Wolbachia, their infection dynamics, and their potential host effects remain unknown. In this study, we report the phylogenetic position and density dynamics of Wolbachia in P. fuscipes. The phylogeny of Wolbachia based on an analysis of MLST genotyping showed that the bacteria from P. fuscipes belong to supergroup B. Quantitative PCR indicated that the infection density in adults was higher than in any other life stage (egg, larva or pupa), and that reproductive tissue in adults had the highest infection densities, with similar densities in the sexes. These findings provide a starting point for understanding the Wolbachia infection dynamics in P. fuscipes, and interactions with other components of the microbiota. Full article

(This article belongs to the Collection Insect Symbionts: Evolution and Application)

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8 pages, 909 KiB

Open AccessArticle

A Meta-Analysis Shows That Screen Bottom Boards Can Significantly Reduce Varroa destructor Population

by Fang Liu, Xinjian Xu, Yuan Zhang, Hongxia Zhao and Zachary Y. Huang

Insects 2020, 11(9), 624; https://doi.org/10.3390/insects11090624 - 11 Sep 2020

Cited by 5 | Viewed by 2675

Abstract

Varroa destructor is by far the most serious threat to the western honey bee, Apis mellifera. A screen bottom board, a cultural method for mite control, is a modified bottom board with a screen that allows mites to fall onto a sticky [...] Read more.

Varroa destructor is by far the most serious threat to the western honey bee, Apis mellifera. A screen bottom board, a cultural method for mite control, is a modified bottom board with a screen that allows mites to fall onto a sticky board, or the grass or soil below the screen. Whether or not a screen bottom board can reduce varroa significantly has been controversial. Most studies show a trend of lower varroa populations in colonies with these boards, but the results are usually not statistically significant. To understand whether the negative results have been due to small sample sizes, or because the board is actually ineffective, we conducted a meta-analysis with seven published studies with a total of 145 colonies. Meta-analysis showed that the confidence intervals of the combined effect sizes were negative with a Hedges’ g of −1.09 (SE 0.39, 95% CI −2.0 to −0.19, p < 0.01), which suggests that the varroa population in colonies with screen bottom boards is significantly lower compared to those with traditional wooden floors. We thus conclude that the screen bottom board does have a significantly negative impact on the varroa population and can be part of tool kits for mite control. Full article

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11 pages, 1748 KiB

Open AccessArticle

Necrobia rufipes (De Geer) Infestation in Pet Food Packaging and Setup of a Monitoring Trap

by Sara Savoldelli, Costanza Jucker, Ezio Peri, Mokhtar Abdulsattar Arif and Salvatore Guarino

Insects 2020, 11(9), 623; https://doi.org/10.3390/insects11090623 - 11 Sep 2020

Cited by 7 | Viewed by 5067

Abstract

Necrobia rufipes (De Geer) (Coleoptera: Cleridae), also known as the red-legged ham beetle, is a newly emerging pest of pet food stores, causing apprehension among producers worldwide. Concerns about this pest are exacerbated by the lack of information about infestation modalities in pet [...] Read more.

Necrobia rufipes (De Geer) (Coleoptera: Cleridae), also known as the red-legged ham beetle, is a newly emerging pest of pet food stores, causing apprehension among producers worldwide. Concerns about this pest are exacerbated by the lack of information about infestation modalities in pet food, while specific monitoring tools are missing. Considering that adequate pet food packaging could limit N. rufipes infestations, information about the penetration modalities in commonly used pet food packaging is needed. Moreover, the development of appropriate monitoring instruments is urgent to detect pest presence early and to reduce chemical treatments for its control. In this paper, the adults’ and larvae’s ability to enter into pet food packaging was evaluated. Furthermore, to develop monitoring traps, behavioral bioassays were done: (1) testing two different commercial adhesive surfaces, one generally used in mouse glue traps (MG), and the other used in cockroach glue traps (CG), to evaluate their different abilities in avoiding insects’ escape; (2) screening different molecules, typical of the substrates attacked by N. rufipes, as candidate food attractants for this pest: methyl cyclopentenolone (MCP), squalene (SQ), and stearic acid (SA). The results show that N. rufipes adults and larvae enter into packaging through the air vent valves on the bottom, suggesting that a way to improve the packaging to prevent insect infestation would be to modify these points of weakness. Laboratory tests show that the different bioassayed glues have strong differences in the ability to retain the caught insects, with MG being more effective than CG. The behavioral bioassay indicated that MCP and SQ attract N. rufipes adults in olfactometer. Finally, the results of dual-choice arena bioassays show that among the candidate attractant tested, a mixture of pet food (PF) and MCP elicited the strongest attraction in N. rufipes adults. These results encourage further experiments with the use of an MG adhesive trap loaded with a mixture of PF+MCP to test the effectiveness of such a tool for monitoring N.rufipes in pet food industries and warehouses. Full article

(This article belongs to the Collection Stored-Product Pests: Biology, Ecology, Behavior and Integrated Management)

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13 pages, 2105 KiB

Open AccessArticle

Kairomone and Camera Trapping New Zealand Flower Thrips, Thrips obscuratus

by David Maxwell Suckling, Mailee E. Stanbury, Ox Lennon, Kate M. Colhoun, Fabio Chinellato and Ashraf M. El-Sayed

Insects 2020, 11(9), 622; https://doi.org/10.3390/insects11090622 - 11 Sep 2020

Cited by 3 | Viewed by 2844

Abstract

This project investigated how kairomone lures, camera traps, and counting software could together contribute to pest management. Images of cumulative daily catch of New Zealand Flower Thrips (NZFT) attracted to a ripe peach lactone (6-pentyl-2H-pyran-2-one; 6-PAP) were automatically loaded to the internet and [...] Read more.

This project investigated how kairomone lures, camera traps, and counting software could together contribute to pest management. Images of cumulative daily catch of New Zealand Flower Thrips (NZFT) attracted to a ripe peach lactone (6-pentyl-2H-pyran-2-one; 6-PAP) were automatically loaded to the internet and compared with scanned bases checked weekly using in-house software and manual counting. Camera traps were able to provide thrips counts equivalent to delta traps, but daily and remotely. An 11-fold greater NZFT count occurred within 24 h in passive traps after polyethylene sachets loaded with 250 mg of 6-PAP were placed in trees. Intensive trapping, by placing 1, 2, 4, and 8 traps per tree (500 mg/trap), resulted in a maximum 32-fold increase in thrips per tree. While 6-PAP has proved to be a useful tool for monitoring NZFT numbers, our results suggest that it is not likely to be suitable for mass trapping. Future research should investigate NZFT behavior to better understand population movement on an area-wide basis. Camera traps can be a valuable tool for recording insect flight activity remotely, but the number of traps required for statistically reliable estimates may be prohibitive. Full article

(This article belongs to the Special Issue Behavioral Manipulation for Pest Control)

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19 pages, 3879 KiB

Open AccessArticle

Population Dynamics of Drosophila suzukii in Coastal and Mainland Sweet Cherry Orchards of Greece

by Stella A. Papanastasiou, Vasilis G. Rodovitis, Evmorfia P. Bataka, Eleni Verykouki and Nikos T. Papadopoulos

Insects 2020, 11(9), 621; https://doi.org/10.3390/insects11090621 - 10 Sep 2020

Cited by 7 | Viewed by 3873

Abstract

Despite the recent invasion and wide spread of Drosophila suzukii Matsumura (Diptera: Drosophilidae) in Europe, little is known regarding its population trends in coastal areas of the southern Mediterranean countries. Using adult trapping and fruit sampling, we studied the population dynamics of D. [...] Read more.

Despite the recent invasion and wide spread of Drosophila suzukii Matsumura (Diptera: Drosophilidae) in Europe, little is known regarding its population trends in coastal areas of the southern Mediterranean countries. Using adult trapping and fruit sampling, we studied the population dynamics of D. suzukii in coastal and mainland (semi-highland) cherry orchards of Greece, from 2018 to 2020. Adults were captured in traps baited with apple cider vinegar, placed in conventional and unmanaged sweet-cherry orchards, and in neighbouring wild growing hosts. Sampling of sweet-cherry fruit to assess infestation levels was conducted from early and late-ripening cherry cultivars in both areas. Adults were captured throughout the year in the coastal area with two peaks registered in spring and late-autumn. Captures were nearly zero during the hot summer months. Flight activity exhibited only one peak in autumn at the mainland area, and ceased during winter and spring. Captures in wild hosts were lower during the sweet-cherry ripening period than later in the season. Higher sweet-cherry infestation levels were recorded in the coastal than in the mainland area and in unmanaged than in commercial orchards. Both early and late-ripening cultivars were highly susceptible to D. suzukii infestation in the coastal area. Infestation rates were higher in late-ripening cultivars than in early-ripening ones in the mainland area. We conclude that D. suzukii has well adapted to the Mediterranean climate of Greece, and is able to progressively exploit several crops and wild hosts of mainland and coastal areas. Full article

(This article belongs to the Special Issue Improving Invasive Insect Species Management)

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