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Insects
Volume 11
Issue 10
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Insects, Volume 11, Issue 10 (October 2020) – 71 articles

Cover Story (view full-size image): Huge migrating locust swarms have been devastating agriculture since ancient times. An important aspect of the locusts’ natural history is their interaction with the bacteria they harbor in and on their body. These locust-associated bacteria affect certain physiological traits (such as immunity and swarm cohesion), as well as possibly being affected by different factors of locust biology. This review summarizes our current knowledge of locust-bacterial interactions, including the relevant bacterial strains and their locations within the insects; the role of the bacteria and their importance to their host’s life; the mechanism of transmitting important bacteria across locust generations; and more. Finally, we offer some new perspectives and research directions that could broaden our understanding of the locust-associated bacteria and their tentative instrumental role in locust outbreaks. View this paper.
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18 pages, 948 KiB  
Review
Plants in the Genus Tephrosia: Valuable Resources for Botanical Insecticides
by Peiwen Zhang, Deqiang Qin, Jianjun Chen and Zhixiang Zhang
Insects 2020, 11(10), 721; https://doi.org/10.3390/insects11100721 - 21 Oct 2020
Cited by 36 | Viewed by 5923
Abstract
Synthetic insecticides are effective in controlling insect pests but can also harm nontarget organisms and the environment. During the last 40 years, there has been an increasing interest in alternative insecticides, particularly those derived from plants, commonly known as botanical insecticides. However, commercially [...] Read more.
Synthetic insecticides are effective in controlling insect pests but can also harm nontarget organisms and the environment. During the last 40 years, there has been an increasing interest in alternative insecticides, particularly those derived from plants, commonly known as botanical insecticides. However, commercially available botanical insecticides remain limited. Rotenone is one of the earliest identified compounds and was used as fish poison and pest management. Due to its link with Parkinson disease, the use of rotenone was banned in many developed countries. Rotenone used to be isolated from Derris spp. and Lonchocarpus spp., and it can also be isolated from Tephrosia species. In this article, we present basic botanical information on selected Tephrosia species and their major compounds related to insecticidal activities and highlight the current use of extracts derived from some species, Tephrosia vogelii in particular, for control of insect pests in stored grains and crop production. The crude extracts contain multiple bioactive compounds, mainly rotenone, deguelin, rotenolone, and tephrosin, which act in either additive or synergistic fashion, resulting in effective control of insect pests. There are about 400 species in the genus Tephrosia, and species and even strains or variants vary greatly in these active compounds. We argue that a systematic evaluation of bioactive compounds in different species are needed, and species or strains with high insecticidal activities should be selected for use in the sustainable control of insect pests. Full article
(This article belongs to the Special Issue Natural Substances against Insect Pests: Assets and Liabilities)
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19 pages, 4189 KiB  
Article
Populations and Host/Non-Host Plants of Spittlebugs Nymphs in Olive Orchards from Northeastern Portugal
by María Villa, Isabel Rodrigues, Paula Baptista, Alberto Fereres and José Alberto Pereira
Insects 2020, 11(10), 720; https://doi.org/10.3390/insects11100720 - 21 Oct 2020
Cited by 13 | Viewed by 2946
Abstract
The Aphrophoridae family contains important vectors of Xylella fastidiosa, a serious bacterial plant disease. In olive orchards, nymphs usually feed on the ground-cover vegetation. However, detailed information about their populations and host/non-host plants in some regions threatened by Xylella, such as [...] Read more.
The Aphrophoridae family contains important vectors of Xylella fastidiosa, a serious bacterial plant disease. In olive orchards, nymphs usually feed on the ground-cover vegetation. However, detailed information about their populations and host/non-host plants in some regions threatened by Xylella, such as the northeast of Portugal, is very limited. The goal of our work was to identify the vector species, nymphal development period, and their host and non-host herbaceous plants in olive orchards from northeastern Portugal. Ground-cover plant species hosting or not hosting nymphs were identified during the spring of 2017 to 2019 in olive orchards. Nymphal development period, nymph aggregation, and nymph’s preferred feeding height of the ground-cover plants were recorded. The most abundant Aphrophoridae species was Philaenus spumarius followed by Neophilaenus sp. Nymphs developed from April to early May and showed a low number of individuals per foam (generally between one and three). They preferred the middle part of the plants. Philaenus spumarius feeds preferentially on Asteraceae and Fabaceae, and Neophilaenus sp. on Poaceae. Some abundant plants, such as Bromus diandrus, Astragalus pelecinus, Chrysanthemum segetum, Trifolium spp., Caryophyllaceae, and Brassicaceae, were barely colonized by Aphrophoridae nymphs. This knowledge is essential for the selection of the species composition of ground-cover vegetation to minimize the presence of vectors of X. fastidiosa in olive groves. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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13 pages, 2439 KiB  
Article
Divergence in Gut Bacterial Community Among Life Stages of the Rainbow Stag Beetle Phalacrognathus muelleri (Coleptera: Lucanidae)
by Miaomiao Wang, Xingjia Xiang and Xia Wan
Insects 2020, 11(10), 719; https://doi.org/10.3390/insects11100719 - 21 Oct 2020
Cited by 15 | Viewed by 5302
Abstract
Although stag beetles are popular saprophytic insects, there are few studies about their gut bacterial community. This study focused on the gut bacterial community structure of the rainbow stag beetle (i.e., Phalacrognathus muelleri) in its larvae (three instars) and adult stages, using [...] Read more.
Although stag beetles are popular saprophytic insects, there are few studies about their gut bacterial community. This study focused on the gut bacterial community structure of the rainbow stag beetle (i.e., Phalacrognathus muelleri) in its larvae (three instars) and adult stages, using high throughput sequencing (Illumina Miseq). Our aim was to compare the gut bacterial community structure among different life stages. The results revealed that bacterial alpha diversity increased from the 1st instar to the 3rd instar larvae. Adults showed the lowest gut bacterial alpha diversity. Bacterial community composition was significantly different between larvae and adults (p = 0.001), and 1st instar larvae (early instar) had significant differences with the 2nd (p= 0.007) and 3rd (p = 0.001) instar larvae (final instar). However, there was little difference in the bacterial community composition between the 2nd and 3rd instar larvae (p = 0.059). Our study demonstrated dramatic shifts in gut bacterial community structure between larvae and adults. Larvae fed on decaying wood and adults fed on beetle jelly, suggesting that diet is a crucial factor shaping the gut bacterial community structure. There were significant differences in bacterial community structure between early instar and final instars larvae, suggesting that certain life stages are associated with a defined gut bacterial community. Full article
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22 pages, 2044 KiB  
Article
Bacterial Communities of Ixodes scapularis from Central Pennsylvania, USA
by Joyce Megumi Sakamoto, Gabriel Enrique Silva Diaz and Elizabeth Anne Wagner
Insects 2020, 11(10), 718; https://doi.org/10.3390/insects11100718 - 20 Oct 2020
Cited by 8 | Viewed by 4107
Abstract
Native microbiota represent a potential resource for biocontrol of arthropod vectors. Ixodes scapularis is mostly inhabited by the endosymbiotic Rickettsia buchneri, but the composition of bacterial communities varies with life stage, fed status, and/or geographic location. We compared bacterial community diversity among [...] Read more.
Native microbiota represent a potential resource for biocontrol of arthropod vectors. Ixodes scapularis is mostly inhabited by the endosymbiotic Rickettsia buchneri, but the composition of bacterial communities varies with life stage, fed status, and/or geographic location. We compared bacterial community diversity among I. scapularis populations sampled within a small geographic range in Central Pennsylvania. We collected and extracted DNA from ticks and sequenced amplicons of the eubacterial 16S rRNA gene from individuals and pooled samples. We then used taxon-specific PCR and/or qPCR to confirm the abundance or infection frequency of select pathogenic and symbiotic bacteria. Bacterial communities were more diverse in pools of males than females and the most abundant taxon was Rickettsia buchneri followed by Coxiellaceae (confirmed by sequencing as an unknown Rickettsiella species). High Rickettsiella titers in pools were likely due to a few heavily infected males. We determined that the infection frequency of Borrelia burgdorferi ranged from 20 to 75%. Titers of Anaplasma phagocytophilum were significantly different between sexes. Amplicon-based bacterial 16S sequencing is a powerful tool for establishing the baseline community diversity and focusing hypotheses for targeted experiments, but care should be taken not to overinterpret data based on too few individuals. We identified intracellular bacterial candidates that may be useful as targets for manipulation. Full article
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15 pages, 3067 KiB  
Article
Metabolic Cost of a Nutritional Symbiont Manifests in Delayed Reproduction in a Grain Pest Beetle
by Tobias Engl, Thorsten H. P. Schmidt, Sthandiwe Nomthandazo Kanyile and Dagmar Klebsch
Insects 2020, 11(10), 717; https://doi.org/10.3390/insects11100717 - 20 Oct 2020
Cited by 15 | Viewed by 3359
Abstract
Animals engage in a plethora of mutualistic interactions with microorganisms that can confer various benefits to their host but can also incur context-dependent costs. The sawtoothed grain beetle Oryzaephilus surinamensis harbors nutritional, intracellular Bacteroidetes bacteria that supplement precursors for the cuticle synthesis and [...] Read more.
Animals engage in a plethora of mutualistic interactions with microorganisms that can confer various benefits to their host but can also incur context-dependent costs. The sawtoothed grain beetle Oryzaephilus surinamensis harbors nutritional, intracellular Bacteroidetes bacteria that supplement precursors for the cuticle synthesis and thereby enhance desiccation resistance of its host. Experimental elimination of the symbiont impairs cuticle formation and reduces fitness under desiccation stress but does not disrupt the host’s life cycle. For this study, we first demonstrated that symbiont populations showed the strongest growth at the end of metamorphosis and then declined continuously in males, but not in females. The symbiont loss neither impacted the development time until adulthood nor adult mortality or lifespan. Furthermore, lifetime reproduction was not influenced by the symbiont presence. However, symbiotic females started to reproduce almost two weeks later than aposymbiotic ones. Thus, symbiont presence incurs a metabolic and context-dependent fitness cost to females, probably due to a nutrient allocation trade-off between symbiont growth and sexual maturation. The O. surinamensis symbiosis thereby represents an experimentally amenable system to study eco-evolutionary dynamics under variable selection pressures. Full article
(This article belongs to the Section Insect Physiology, Reproduction and Development)
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14 pages, 1299 KiB  
Article
Selectivity of Entomopathogenic Fungi to Chrysoperla externa (Neuroptera: Chrysopidae)
by Pamella Mingotti Dias, Elisângela de Souza Loureiro, Luis Gustavo Amorim Pessoa, Gabriel Luiz Reis Devoz, Gilson Bárbaro Barbosa Junior, Allan Macali Werner, Acacio Aparecido Navarrete and Paulo Eduardo Teodoro
Insects 2020, 11(10), 716; https://doi.org/10.3390/insects11100716 - 19 Oct 2020
Cited by 8 | Viewed by 3120
Abstract
We aimed to evaluate the selectivity of entomopathogenic fungi to larvae of Chrysoperla externa (Neuroptera: Chrysopidae). For this purpose, Beauveria bassiana (strain ESALQ PL63), Metarhizium anisopliae (strain ESALQ E9) and Metarhizium rileyi (strain UFMS 03) were assessed at different concentrations (1 × 10 [...] Read more.
We aimed to evaluate the selectivity of entomopathogenic fungi to larvae of Chrysoperla externa (Neuroptera: Chrysopidae). For this purpose, Beauveria bassiana (strain ESALQ PL63), Metarhizium anisopliae (strain ESALQ E9) and Metarhizium rileyi (strain UFMS 03) were assessed at different concentrations (1 × 107, 1 × 108 and 1 × 109 conidia mL−1). The control treatment consisted of distilled water and Tween80 0.01. The treatments were applied with a Potter spray tower using two different methodologies: direct application (DA) and dry film (DF). Up to 96 h after application, no treatment provided a larval mortality above 3%. After 120 h, only B. bassiana induced significant mortality in all instars, with rates of 26%, 17% and 10% for first, second and third instar larval periods, respectively. There was no difference regarding to the application method or concentration of conidia. The percentage of individuals that revealed changes in the length of the larval and pupal periods varied among different treatments with entomopathogenic fungi and control treatments, application methodologies and concentrations. Despite B. bassiana revealing a higher mortality than M. anisopliae and M. rileyi on larvae of C. externa, these three entomopathogenic fungi may be used in association with C. externa for sustainable pest management. Full article
(This article belongs to the Special Issue Biological Control and Insect Pathology)
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10 pages, 1336 KiB  
Article
Spatial Distribution and Flight Patterns of Two Grain Storage Insect Pests, Rhyzopertha dominica (Bostrichidae) and Tribolium castaneum (Tenebrionidae): Implications for Pest Management
by Joanne C. Holloway, Gregory J. Daglish and David G. Mayer
Insects 2020, 11(10), 715; https://doi.org/10.3390/insects11100715 - 19 Oct 2020
Cited by 10 | Viewed by 3287
Abstract
The lesser grain borer, Rhyzopertha dominica, and the rust red flour beetle, Tribolium castaneum, are two major beetle pests commonly found infesting stored products worldwide. Both species can cause severe economic damage and their management is complicated by their potential to [...] Read more.
The lesser grain borer, Rhyzopertha dominica, and the rust red flour beetle, Tribolium castaneum, are two major beetle pests commonly found infesting stored products worldwide. Both species can cause severe economic damage and their management is complicated by their potential to develop resistance to several of the limited chemical options available. However, pest management strategies can be improved by understanding the ecology of the pest insect. To determine the spatiotemporal activity of R. dominica and T. castaneum, we conducted a trapping study over two years in a temperate region of south-eastern Australia, with traps located near grain storages and fields. We captured higher numbers of R. dominica than T. castaneum, and both species were more prevalent in traps located close to grain storages. Similar and consistent seasonal patterns were displayed by both species with activity ceasing during the winter (June–August) months. We found linear correlations between maximum daily temperatures and trap catches, and minimum threshold temperatures for flight activity were 14.5 °C and 15.6 °C for R. dominica and T. castaneum, respectively. The results are discussed in relation to the ecology of these pests along with their implications for pest management. Full article
(This article belongs to the Collection Stored-Product Pests: Biology, Ecology, Behavior and Integrated Management)
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16 pages, 260 KiB  
Article
The Impact of Plant Essential Oils and Fine Mesh Row Covers on Flea Beetle (Chrysomelidae) Management in Brassicaceous Greens Production
by Robert Brockman, Ryan Kuesel, Kendall Archer, Kyla O'Hearn, Neil Wilson, Delia Scott, Mark Williams, Ricardo Bessin and David Gonthier
Insects 2020, 11(10), 714; https://doi.org/10.3390/insects11100714 - 19 Oct 2020
Cited by 7 | Viewed by 2918
Abstract
Brassicaceous leafy greens are an important crop for small growers but are difficult to produce due to damage by flea beetles. Flea beetles are problematic for growers as they chew many small holes through leaves rendering produce unmarketable. We tested the efficacy of [...] Read more.
Brassicaceous leafy greens are an important crop for small growers but are difficult to produce due to damage by flea beetles. Flea beetles are problematic for growers as they chew many small holes through leaves rendering produce unmarketable. We tested the efficacy of several essential oils, the woven-mesh row cover ProtekNet, and the spunbonded row cover Agribon, compared to organic and conventional insecticides and no spray controls in the spring and fall of 2019. We found that the two row cover treatments (Agribon and ProtekNet) provided the best control of flea beetles and associated damage. Thyme oil was highly phytotoxic and killed the crop entirely and rosemary and neem essential oils caused mild phytotoxic burns. Organic insecticides rarely performed better than the no spray control. While conventional insecticides controlled most flea beetles, the crop was often still too highly damaged to sell. The results of our study suggest row covers offer producers an effective method of flea beetle control that reduces their dependence on insecticides for conventional and organic 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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11 pages, 1176 KiB  
Article
Changes in the Honeybee Antioxidant System after 12 h of Exposure to Electromagnetic Field Frequency of 50 Hz and Variable Intensity
by Paweł Migdał, Agnieszka Murawska, Aneta Strachecka, Paweł Bieńkowski and Adam Roman
Insects 2020, 11(10), 713; https://doi.org/10.3390/insects11100713 - 18 Oct 2020
Cited by 16 | Viewed by 3560
Abstract
In recent years, on a global scale, more and more reports of a phenomenon called CCD (Colony Collapse Disorder) have been reported. In addition to pesticides, diseases, and other environmental stressors, electromagnetic fields are also mentioned as one of the possible causes of [...] Read more.
In recent years, on a global scale, more and more reports of a phenomenon called CCD (Colony Collapse Disorder) have been reported. In addition to pesticides, diseases, and other environmental stressors, electromagnetic fields are also mentioned as one of the possible causes of CCD. One of the body’s first lines of defense against harmful factors is the antioxidant system. We hypothesized that electromagnetic field upregulate the activity of SOD (superoxide dismutase), CAT (catalases), and changed FRAP (total antioxidant potential) in honeybee hemolymph. In our research, 12 h bee’s exposure to E-field was analyzed to determine changes in the antioxidant system. The frequency of 50 Hz and various intensities were used: 5.0 kV/m, 11.5 kV/m, 23.0 kV/m, and 34.5 kV/m. Superoxide dismutase was characterized by four times higher activity in the study groups as compared to the control group. Catalase activity in all groups was characterized by statistically significantly different activity between the groups. The highest activity was recorded in the 34.5 kV/m group. The lowest activity was recorded in the 11.5 kV/m group. A relationship was found between different E-field intensities and changes in the antioxidant system. Full article
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23 pages, 296 KiB  
Review
Models of Diabrotica Populations: Demography, Population Genetics, Geographic Spread, and Management
by David W. Onstad, Michael A. Caprio and Zaiqi Pan
Insects 2020, 11(10), 712; https://doi.org/10.3390/insects11100712 - 17 Oct 2020
Cited by 6 | Viewed by 2371
Abstract
Both Diabrotica virgifera virgifera LeConte and D. barberi Smith and Lawrence are among the most damaging insects impacting corn in North America. D. virgifera virgifera has also invaded Europe and has become an important pest in that region. Computer models have become an [...] Read more.
Both Diabrotica virgifera virgifera LeConte and D. barberi Smith and Lawrence are among the most damaging insects impacting corn in North America. D. virgifera virgifera has also invaded Europe and has become an important pest in that region. Computer models have become an important tool for understanding the impact and spread of these important pests. Over the past 30 years, over 40 models have been published related to these pests. The focus of these models range from occupancy models (particularly for Europe), impact of climate change, range expansion, economics of pest management, phenology, to the evolution of resistance to toxins and crop rotation. All of these models share characteristics. We elaborate on the methods in which modelers have incorporated the biology of these pests, including density-dependence, movement, fecundity and overwintering mortality. We discuss the utility of both spatially-explicit, complex models and spatially-implicit, generational models and where each might be appropriate. We review resistance models that either explain past evolution to crop rotation, insecticides or insecticidal traits or attempt to predict the consequences of resistance management strategies. Full article
(This article belongs to the Special Issue Corn Rootworm: Biology, Ecology, Behavior and Integrated Management)
15 pages, 2595 KiB  
Article
Environmental Tolerance of Entomopathogenic Fungi: A New Strain of Cordyceps javanica Isolated from a Whitefly Epizootic Versus Commercial Fungal Strains
by Shaohui Wu, Michael D. Toews, Camila Oliveira-Hofman, Robert W. Behle, Alvin M. Simmons and David I. Shapiro-Ilan
Insects 2020, 11(10), 711; https://doi.org/10.3390/insects11100711 - 17 Oct 2020
Cited by 25 | Viewed by 3764
Abstract
A new strain of Cordyceps javanica (wf GA17) was observed causing widespread epizootics among whiteflies in Southern Georgia in 2017. The tolerance of conidia to environmental factors including variable temperature and ultraviolet (UV) light was compared between this strain and three commercial strains [...] Read more.
A new strain of Cordyceps javanica (wf GA17) was observed causing widespread epizootics among whiteflies in Southern Georgia in 2017. The tolerance of conidia to environmental factors including variable temperature and ultraviolet (UV) light was compared between this strain and three commercial strains of entomopathogenic fungi (Metarhizium brunneum F52, Cordyceps fumosorosea Apopka97, and Beauveria bassiana GHA). Under 10–30 °C, C. javanica wf GA17 responded similarly to other fungi, with the highest virulence against Galleria mellonella at 25 °C, followed by 20, 30, and 15 °C; lowest virulence was observed at 10 °C. At 35 °C and 40 °C, C. javanica wf GA17 had lower tolerance than M. brunneum F52 and B. bassiana GHA, but was superior to C. fumosorosea Apopka97 in conidia viability and post-treatment virulence. After exposure to −20 °C for 56 d, C. javanica wf GA17 exhibited lower germination than M. brunneum F52 and lower virulence than M. brunneum F52 and B. bassiana GHA, but higher germination and virulence than C. fumosorosea Apopka97. Following exposure to strong UV light, viability and virulence of all fungi were reduced with increasing exposure periods. Increased environmental tolerance of C. javanica wf GA17 over C. fumosorosea Apopka97 suggests that the new strain could have applicability for commercial pest management. Full article
(This article belongs to the Special Issue Improving Whitefly Management)
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22 pages, 11134 KiB  
Article
Biodiversity Inventory and Distribution of Metriorrhynchina Net-Winged Beetles (Coleoptera: Lycidae), with the Identification of Generic Ranges
by Ladislav Bocak, Michal Motyka, Dominik Kusy and Renata Bilkova
Insects 2020, 11(10), 710; https://doi.org/10.3390/insects11100710 - 16 Oct 2020
Cited by 3 | Viewed by 5753
Abstract
We reviewed the species-level classification of Metriorrhynchina net-winged beetles to make the group accessible for further studies. Altogether, 876 valid species are listed in a checklist along with known synonyms, combinations, and distribution data. The compilation of geographic distribution showed that Metriorrhynchina is [...] Read more.
We reviewed the species-level classification of Metriorrhynchina net-winged beetles to make the group accessible for further studies. Altogether, 876 valid species are listed in a checklist along with known synonyms, combinations, and distribution data. The compilation of geographic distribution showed that Metriorrhynchina is distributed mainly in the Australian region with very high diversity in the islands at the northern edge of the Australian craton, i.e., in the Moluccas and New Guinea (54 and 423 spp. respectively). The neighboring northern part of the Australian continent houses a majority of known Australian species (112 spp.) and the diversity of net-winged beetles gradually decreases to the south (43 spp.). The fauna of Sulawesi is highly endemic at the generic level (4 of 10 genera, 67 of 84 spp.). Less Metriorrhynchina occur in the Solomon Islands and Oceania (in total 22 spp.). The Oriental Metriorrhynchina fauna consists of a few genera and a limited number of species, and most of these are known from the Philippines (51 of 94 Oriental spp.). We identified a high species level turn-over between all neighboring landmasses. The genus-level endemism is high in Sulawesi (4 genera) and New Guinea (11 genera), but only a single genus is endemic to Australia. During the compilation of the checklist, we identified some homonyms, and we propose the following replacement names and a new synonym: Metriorrhynchus pseudobasalis, nom. nov. for M. basalis Lea, 1921 nec M. basalis Bourgeois, 1911; Metriorrhynchus pseudofunestus, nom. nov. for M. funestus Lea, 1921 nec M. funestus (Guérin-Méneville, 1838), Trichalus pseudoternatensis, nom. nov. for T. ternatensis Kleine, 1930 nec T. ternatensis Bourgeois, 1900, Procautires subparallelus, nom. nov. for P. parallelus (Pic, 1926) nec P. parallelus (Bourgeois, 1883), and Cautires pseudocorporaali, nom. nov. for C. corporaali (Pic, 1921: 12), (formerly Odontocerus and Cladophorus) nec C. corporaali (Pic, 1921) (formerly Bulenides, later Cautires). Diatrichalus biroi Kleine, 1943, syn. nov. is proposed as a junior subjective synonym of D. subarcuatithorax (Pic, 1926). Altogether, 161 new combinations are proposed, and 47 species earlier placed in Xylobanus Waterhouse, 1879 transferred from Cautirina to Metriorrhynchina incertae sedis. The study clarifies the taxonomy of Metriorrhynchini and should serve as a restarting point for further taxonomic, evolutionary, and biogeographic studies. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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27 pages, 3948 KiB  
Article
A Survey of the Brazilian Dicranocentrus Schött (Collembola, Orchesellidae, Heteromurini) with the Description of a New Species and Notes on the Genus
by Bruno C. Bellini, Nikolas G. Cipola and Orquianne J. R. Siqueira
Insects 2020, 11(10), 709; https://doi.org/10.3390/insects11100709 - 16 Oct 2020
Cited by 9 | Viewed by 3312
Abstract
Dicranocentrus Schött is the most diverse and widespread taxon of Neotropical Orchesellidae. In Brazil, the genus is represented by 11 species found in humid forested areas of Atlantic and Amazon forests domains. Here we describe in detail Dicranocentrus abestado sp. nov. from Chapada [...] Read more.
Dicranocentrus Schött is the most diverse and widespread taxon of Neotropical Orchesellidae. In Brazil, the genus is represented by 11 species found in humid forested areas of Atlantic and Amazon forests domains. Here we describe in detail Dicranocentrus abestado sp. nov. from Chapada Diamantina, Caatinga domain, Brazil. The new species belongs to the marias group sensu Mari-Mutt, due to the absence of most posterior macrochaetae on the dorsal head, and resembles other Neotropical species with 3, 2 and 2 central macrochaetae on abdominal segments I–III. However, the new species is unique especially by its reduced colour pattern combined with its empodial complex morphology. We compare Dicranocentrus abestado sp. nov. with 27 other taxa from the New and Old World, including all species with 3 macrochaetae on the first abdominal segment; provide notes and details on the morphology of the compared species plus identification keys to Brazilian and all species of the genus with similar abdominal chaetotaxy. We also discuss the current taxonomical knowledge on Brazilian Dicranocentrus and provide notes on its chaetotaxy and Heteromurinae systematics. Full article
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19 pages, 4259 KiB  
Article
First Account of Phylogeographic Variation, Larval Characters, and Laboratory Rearing of the Endangered Cobblestone Tiger Beetle Cicindelidia marginipennis, Dejean, 1831 with Observations of Their Natural History
by Rodger A. Gwiazdowski, Jeremy C. Andersen, C. Barry Knisley, Brian P. Griffin and Joseph S. Elkinton
Insects 2020, 11(10), 708; https://doi.org/10.3390/insects11100708 - 16 Oct 2020
Cited by 2 | Viewed by 2816
Abstract
The cobblestone tiger beetle, Cicindelidia marginipennis (Dejean, 1831) is a North American species specializing in riparian habitats from New Brunswick, Canada, to Alabama in the United States. In the United States, this species is state-listed as threatened or endangered range-wide and periodically receives [...] Read more.
The cobblestone tiger beetle, Cicindelidia marginipennis (Dejean, 1831) is a North American species specializing in riparian habitats from New Brunswick, Canada, to Alabama in the United States. In the United States, this species is state-listed as threatened or endangered range-wide and periodically receives consideration for federal listing, mostly due to habitat decline. Despite its conservation status, intraspecific genetic diversity for this species has not been explored and little is known about its natural history. To support further inquiry into the biology of C. marginipennis, this study provides the first look at range-wide genetic diversity using mitochondrial DNA (mtDNA), describes all three larval instars, and describes natural history characteristics from captive rearing and field observation. Based on mtDNA analyses, our results suggest that geographically based population structure may exist throughout the range, with individuals from Alabama possessing haplotypes not found elsewhere in our sampling. Further genetic analyses, particularly multi-locus analyses, are needed to determine whether the Alabama population represents a separate cryptic species. Our morphological analysis and descriptions of larval instars reveal a combination of characteristics that can be used to differentiate C. marginipennis from closely related and co-occurring species. Based on our field observations, we find that the larval “throw pile” of soil excavated from burrows is a key search image for locating larvae, and we provide descriptions and detailed photographs to aid surveys. Lastly, we find that this species can be successfully reared in captivity and provide guidelines to aid future recovery efforts. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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12 pages, 3356 KiB  
Article
Identifying the Biological Characteristics Associated with Oviposition Behavior of Tea Leafhopper Empoasca onukii Matsuda Using the Blue Light Detection Method
by Qi Yao, Huining Zhang, Long Jiao, Xiaoming Cai, Manqun Wang and Zongmao Chen
Insects 2020, 11(10), 707; https://doi.org/10.3390/insects11100707 - 16 Oct 2020
Cited by 6 | Viewed by 2587
Abstract
Tea leafhopper (Empoasca onukii Matsuda) is amongst the key pests in tea plantations around the East Asian region. Stereomicroscopy is a conventional method used for detecting tea leafhopper eggs by dissecting the tender tissues. However, there is a need for a faster [...] Read more.
Tea leafhopper (Empoasca onukii Matsuda) is amongst the key pests in tea plantations around the East Asian region. Stereomicroscopy is a conventional method used for detecting tea leafhopper eggs by dissecting the tender tissues. However, there is a need for a faster and more efficient method to directly observe and investigate intact eggs within tea shoots. The absence of a proven method limits research efforts for determining the oviposition behavior of E. onukii. Herein, we applied the blue light detection method (BLDM), a technique recently developed for other species, in order to detect E. onukii eggs directly and non-destructively within the tender shoot. In addition, we compared BLDM against the traditional stereomicroscope detection method (SMDM) for four tea cultivars. Notably, our results revealed that BLDM was precise and effective in measuring the egg laying quantity of E. onukii on intact tea shoots. Neither tea cultivars nor egg density in the tender shoot significantly affected the accuracy of BLDM. Furthermore, biological characteristics that have rarely been reported previously for E. onukii were investigated using the BLDM, including zygote duration, ovipositional rhythm, egg distribution within the tender shoot, and in different leaf positions, numbers of eggs laid by a single female daily, and laid by the entire generation. Therefore, these findings provide insights into the basic and theoretical evidence for the strategy and mechanism associated with the oviposition behavior of E. onukii. Full article
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13 pages, 2705 KiB  
Article
Effectiveness and Selectiveness of Traps and Baits for Catching the Invasive Hornet Vespa velutina
by Simone Lioy, Daniela Laurino, Michela Capello, Andrea Romano, Aulo Manino and Marco Porporato
Insects 2020, 11(10), 706; https://doi.org/10.3390/insects11100706 - 16 Oct 2020
Cited by 30 | Viewed by 5898
Abstract
Vespa velutina is an invasive hornet that is colonising several countries worldwide, with detrimental effects on multiple components but primarily affecting honey bees and native insect species. Traps for wasps and hornets are commonly used for trapping V. velutina, both for monitoring [...] Read more.
Vespa velutina is an invasive hornet that is colonising several countries worldwide, with detrimental effects on multiple components but primarily affecting honey bees and native insect species. Traps for wasps and hornets are commonly used for trapping V. velutina, both for monitoring and control purposes. In this study, we compared the performances of two typologies of traps and baits widely used for trapping this invasive hornet, by evaluating their effectiveness and selectiveness in trapping V. velutina in two sites during two different periods of the year, spring and autumn. The performance of the traps changed in relation to (i) the trap’s model, (ii) the bait’s typology and (iii) the period of the year. In spring, traps with common beer as bait were more effective and more selective independently of trap’s model than the commercial bait that has been tested. On the contrary, in autumn, just one combination of trap and attractant (the commercial trap and bait) achieved higher effectiveness and selectiveness. Despite the underlined variations among traps and baits, overall catches of V. velutina were scanty compared to bycatches of non-target insects, since best performing traps either in term of effectiveness and selectiveness caught 3.65% of the target species in spring and 1.35% in autumn upon the total trapped insects. This highlights the urgent necessity of developing more selective trapping methods for monitoring and particularly for controlling purposes. Full article
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18 pages, 3545 KiB  
Article
Transcriptomic and Metabolomic Responses of Rice Plants to Cnaphalocrocis medinalis Caterpillar Infestation
by Yuqi Wang, Qingsong Liu, Lixiao Du, Eric M. Hallerman and Yunhe Li
Insects 2020, 11(10), 705; https://doi.org/10.3390/insects11100705 - 15 Oct 2020
Cited by 27 | Viewed by 4110
Abstract
Interactions between plants and insect herbivores are important determinants of plant productivity in cultivated and natural agricultural fields. The rice leaf folder (Cnaphalocrocis medinalis) causes tremendous damage to rice production in Asian countries. However, little information is available about how rice [...] Read more.
Interactions between plants and insect herbivores are important determinants of plant productivity in cultivated and natural agricultural fields. The rice leaf folder (Cnaphalocrocis medinalis) causes tremendous damage to rice production in Asian countries. However, little information is available about how rice plants defend themselves against this destructive pest at molecular and biochemical levels. Here, we observed the transcriptomic and metabolomic differences in rice leaves after 0, 1, 6, 12, and 24 h of being fed by C. medinalis using RNA sequencing and metabolome profiling. Transcriptional analyses showed that gene expression responds rapidly to leaf folder infestation, with the most significant transcriptional changes occurring within 6 h after the initiation of feeding. Metabolite abundance changed more slowly than gene expression. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that the rice transcriptional response to infestation involved genes encoding protein kinases, transcription factors, biosynthesis of secondary metabolites, photosynthesis, and phytohormone signaling. Moreover, the jasmonic acid-dependent signaling pathway triggered by leaf folder herbivory played a vital role in rice defense against this pest. Taken together, our results provide comprehensive insights into the defense system of rice to this species and may inform the development of insect-resistant rice varieties. Full article
(This article belongs to the Collection Plant Responses to Insect Herbivores)
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11 pages, 1320 KiB  
Article
Antimicrobial Activity of an Extract of Hermetia illucens Larvae Immunized with Lactobacillus casei against Salmonella Species
by Kyu-Shik Lee, Eun-Young Yun and Tae-Won Goo
Insects 2020, 11(10), 704; https://doi.org/10.3390/insects11100704 - 15 Oct 2020
Cited by 34 | Viewed by 5051
Abstract
The expressions of antimicrobial peptides (AMPs) in the larvae of the black soldier fly, Hermetia illucens, were significantly increased by pathogen or stimulant induced innate immunity activation. We immunized H. illucens fifth instar larvae with five different Lactobacillus species, that is, Lactobacillus [...] Read more.
The expressions of antimicrobial peptides (AMPs) in the larvae of the black soldier fly, Hermetia illucens, were significantly increased by pathogen or stimulant induced innate immunity activation. We immunized H. illucens fifth instar larvae with five different Lactobacillus species, that is, Lactobacillus acidophilus, L. brevis, L. casei, L. fermentum, or L. delbrueckii, to induce the mass production of AMPs and selected optimal immune inducers. Antimicrobial activities in hemolymph and H. illucens larvae (HIL) extract were evaluated against three salmonella species (Salmonella pullorum, Salmonella typhimurium, and Salmonella enteritidis). Highest antimicrobial activity was shown by the hemolymph of HIL immunized by L. casei and its activity was closely linked with the inductions of cecropin 1 (HiCec1) and defensin 1 (HiDef1) gene expressions. Furthermore, antimicrobial activity in hemolymph was stable to heat and pH and the growth of three Salmonella species were dramatically suppressed by HIL hemolymph and extract after immunization with L. casei. The minimal inhibitory concentration (MICs) of L. casei-immunized HIL extract against Staphylococcus aureus, Escherichia coli, and Salmonella species ranged from 100~200 µg/100 µL and no cytotoxicity to CaCo-2 and L929 cells were observed in the concentration range 100~40,000 µg/100 µL. Taken together, the present investigation demonstrates that L. casei-immunized HIL extract is a powerful natural antibiotic and preservative that can prevent contamination by Salmonella species. Full article
(This article belongs to the Special Issue Insects and Their Derivatives for Human Practical Uses)
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9 pages, 435 KiB  
Article
Evaluating Response of Mass-Reared and Irradiated Navel Orangeworm, Amyelois transitella (Lepidoptera: Pyralidae), to Crude Female Pheromone Extract
by Joshua Reger, Jacob Wenger, Gurreet Brar, Charles Burks and Houston Wilson
Insects 2020, 11(10), 703; https://doi.org/10.3390/insects11100703 - 15 Oct 2020
Cited by 4 | Viewed by 2462
Abstract
The navel orangeworm, Amyleois transitella (Lepidoptera: Pyralidae), is a key pest of almonds and pistachios in California. Larvae directly feed on nuts, reducing quality and yield, and adults can introduce fungi that produce aflatoxins. The development of sterile insect technique (SIT) is currently [...] Read more.
The navel orangeworm, Amyleois transitella (Lepidoptera: Pyralidae), is a key pest of almonds and pistachios in California. Larvae directly feed on nuts, reducing quality and yield, and adults can introduce fungi that produce aflatoxins. The development of sterile insect technique (SIT) is currently being explored as a management tool for this pest. Large quantities of A. transitella are mass-reared, irradiated, and shipped to California from a USDA APHIS facility in Phoenix, AZ. Preliminary field releases of sterile A. transitella from this facility resulted in poor recovery of males in pheromone traps, raising concerns that mass-reared male A. transitella may not be responding to pheromone from virgin females. In this study, a wind tunnel was used to evaluate the response of both irradiated and non-irradiated mass-reared A. transitella males to crude pheromone extract from females, and their performance was compared to two strains of locally reared non-irradiated A. transitella. While initial responses associated with pheromone detection where similar between mass-reared and locally reared moths, a lower proportion of the mass-reared moths ultimately made contact with the pheromone source. Surprisingly, the addition of irradiation did not further decrease their performance. While mass-reared moths respond to pheromone, their ability to locate and make contact with the pheromone source appears to be impeded. The underlying mechanism remains unclear, but is likely related to damage incurred during the mass-rearing and shipping process. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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11 pages, 1846 KiB  
Article
Effect of Cleaning Multiple-Funnel Traps on Captures of Bark and Woodboring Beetles in Northeastern United States
by Kevin J. Dodds and Marc F. DiGirolomo
Insects 2020, 11(10), 702; https://doi.org/10.3390/insects11100702 - 14 Oct 2020
Cited by 7 | Viewed by 3025 | Correction
Abstract
Two experiments were conducted in mixed hardwood-conifer forests in the northeastern United States to test the effects of cleaning surfactant and non-surfactant treated multiple-funnel traps used to catch bark and woodboring beetles. Large amounts of pollen and other debris often form a crust [...] Read more.
Two experiments were conducted in mixed hardwood-conifer forests in the northeastern United States to test the effects of cleaning surfactant and non-surfactant treated multiple-funnel traps used to catch bark and woodboring beetles. Large amounts of pollen and other debris often form a crust on the interior of traps (personal observations). Such surface deposits may provide footholds for beetles to escape capture in traps. In one experiment, we tested cleaned surfactant and non-surfactant traps against non-cleaned surfactant and non-surfactant traps. In a second experiment, we tested field cleaning of modified multiple-funnel traps as an alternative to substituting clean traps on each collection visit. There was no effect of surfactant treated traps, cleaned or not, on total beetles or individual bark beetle species captured. However, in situ cleaned traps were statistically better at capturing total beetles, total bark beetles, and several bark beetle species than non-cleaned control traps. Surfactant-treated non-modified traps and cleaned modified traps had higher species richness and abundance than other treatments at the site level. Our results suggest that cleaning traps to remove accumulated pollen and debris may be helpful for some species but would have limited benefit for broad-scale trapping of bark and woodboring beetles in northeastern forests. Full article
(This article belongs to the Collection Surveillance Tools and Monitoring Strategies for Native and Exotic Forest Insects)
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13 pages, 1402 KiB  
Article
Persistence of Mating Suppression of the Indian Meal Moth Plodia Interpunctella in the Presence and Absence of Commercial Mating Disruption Dispensers
by Leanage K. W. Wijayaratne and Charles S. Burks
Insects 2020, 11(10), 701; https://doi.org/10.3390/insects11100701 - 14 Oct 2020
Cited by 8 | Viewed by 2470
Abstract
The Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is controlled by commercial mating disruption dispensers using passive release to emit high concentrations (relative to females or monitoring lures) of their principal sex pheromone component, (9Z,12E)-tetradecadienyl acetate. Since P. interpunctella is [...] Read more.
The Indian meal moth Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is controlled by commercial mating disruption dispensers using passive release to emit high concentrations (relative to females or monitoring lures) of their principal sex pheromone component, (9Z,12E)-tetradecadienyl acetate. Since P. interpunctella is sexually active throughout the scotophase, an assay system was developed to determine the importance of direct interaction of the male with the dispenser, and whether exposure to mating disruption early in the night is sufficient to suppress mating throughout the night. Exposure to mating disruption dispensers in the mating assay chamber for the first two hours of a 10-h scotophase significantly reduced mating when females were introduced four hours later. Mating was also reduced to a lesser degree in a concentration-dependent manner based solely on re-emission of pheromone, and when males were exposed outside the mating assay chamber. These results indicate that the commercial mating disruption dispensers can suppress mating throughout the night based on interaction with the dispenser early in the night. Desensitization resulting from attraction to a high-concentration pheromone source is important to this suppression, but other factors such as re-emission from the environment may also have a role. These observations imply a non-competitive mechanism for P. interpunctella with the product studied, and suggest that effectiveness of the mating disruption dispenser might be augmented by using them in conjunction with another formulation such as an aerosol or micro-encapsulated product. Full article
(This article belongs to the Collection Stored-Product Pests: Biology, Ecology, Behavior and Integrated Management)
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13 pages, 4267 KiB  
Article
BmFoxO Gene Regulation of the Cell Cycle Induced by 20-Hydroxyecdysone in BmN-SWU1 Cells
by Qian Zhang, Jigui Yang, Peng Chen, Taihang Liu, Qin Xiao, Xiaolin Zhou, Ling Wang, Yanbi Long, Zhanqi Dong, Minhui Pan and Cheng Lu
Insects 2020, 11(10), 700; https://doi.org/10.3390/insects11100700 - 14 Oct 2020
Cited by 4 | Viewed by 3142
Abstract
Ecdysteroid titer determines the state of the cell cycle in silkworm (Bombyxmori) metamorphosis. However, the mechanism of this process is unclear. In this study, we demonstrated that the BmFoxO gene participates in the regulation of the cell cycle induced by [...] Read more.
Ecdysteroid titer determines the state of the cell cycle in silkworm (Bombyxmori) metamorphosis. However, the mechanism of this process is unclear. In this study, we demonstrated that the BmFoxO gene participates in the regulation of the cell cycle induced by 20-Hydroxyecdysone (20E) in BmN-SWU1 cells. The 20E blocks the cell cycle in the G2/M phase through the ecdysone receptor (EcR) and inhibits DNA replication. The 20E can promote BmFoxO gene expression. Immunofluorescence and Western blot results indicated that 20E can induce BmFoxO nuclear translocation in BmN-SWU1 cells. Overexpression of the BmFoxO gene affects cell cycle progression, which results in cell cycle arrest in the G0/G1 phase as well as inhibition of DNA replication. Knockdown of the BmFoxO gene led to cell accumulation at the G2/M phase. The effect of 20E was attenuated after BmFoxO gene knockdown. These findings increase our understanding of the function of 20E in the regulation of the cell cycle in B. mori. Full article
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20 pages, 2800 KiB  
Article
Landscape and Anthropogenic Factors Associated with Adult Aedes aegypti and Aedes albopictus in Small Cities in the Southern Great Plains
by Jordan D. Sanders, Justin L. Talley, Amy E. Frazier and Bruce H. Noden
Insects 2020, 11(10), 699; https://doi.org/10.3390/insects11100699 - 13 Oct 2020
Cited by 8 | Viewed by 2438
Abstract
As mosquito-borne diseases are a growing human health concern in the United States, the distribution and potential arbovirus risk from container-breeding Aedes mosquitoes is understudied in the southern Great Plains. The aim of the study was to assess landscape and anthropogenic factors associated [...] Read more.
As mosquito-borne diseases are a growing human health concern in the United States, the distribution and potential arbovirus risk from container-breeding Aedes mosquitoes is understudied in the southern Great Plains. The aim of the study was to assess landscape and anthropogenic factors associated with encountering adult container-breeding mosquitoes in small cities in southern Oklahoma. Collections were carried out over a 10 week period from June to August 2017 along two geographical transects, each consisting of three cities, equally distant from the Red River/Texas border. Mosquitoes were collected weekly using two trap types along with data for 13 landscape, vegetation, and anthropogenic variables. After five rounds of collection, 6628 female mosquitoes were collected over 2110 trap-nights involving 242 commercial or residential sites in six cities. Of the mosquitoes collected, 80% consisted of container-breeding species: Aedes albopictus (72%), Culex pipiens complex (16%) and Aedes aegypti (8%). Regionally, Aedes aegypti was more likely present in cities closest to the Texas border while Ae. albopictus was spread throughout the region. In general, Ae. aegypti and Ae. albopictus were significantly more present in sites featuring no or low vegetation and residential sites. Variables associated with Ae. albopictus presence and abundance varied between cities and highlighted the urban nature of the species. The study highlighted the distribution of Ae. aegypti geographically and within the urban context, indicated potential habitat preferences of container-breeding mosquito species in small towns, and demonstrated the usefulness of Gravid Aedes traps (GAT) traps for monitoring Aedes populations in urban habitats in small cities. Full article
(This article belongs to the Special Issue Urban Pests and Vectors: Interdisciplinary Links between Arthropod–Human Systems)
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18 pages, 693 KiB  
Article
Ameliorative Effects of Phytochemical Ingestion on Viral Infection in Honey Bees
by Edward M. Hsieh, May R. Berenbaum and Adam G. Dolezal
Insects 2020, 11(10), 698; https://doi.org/10.3390/insects11100698 - 13 Oct 2020
Cited by 14 | Viewed by 3394
Abstract
Honey bee viruses are capable of causing a wide variety of devastating effects, but effective treatments have yet to be discovered. Phytochemicals represent a broad range of substances that honey bees frequently encounter and consume, many of which have been shown to improve [...] Read more.
Honey bee viruses are capable of causing a wide variety of devastating effects, but effective treatments have yet to be discovered. Phytochemicals represent a broad range of substances that honey bees frequently encounter and consume, many of which have been shown to improve honey bee health. However, their effect on bee viruses is largely unknown. Here, we tested the therapeutic effectiveness of carvacrol, thymol, p-coumaric acid, quercetin, and caffeine on viral infection by measuring their ability to improve survivorship in honey bees inoculated with Israeli acute paralysis virus (IAPV) using high-throughput cage bioassays. Among these candidates, caffeine was the only phytochemical capable of significantly improving survivorship, with initial screening showing that naturally occurring concentrations of caffeine (25 ppm) were sufficient to produce an ameliorative effect on IAPV infection. Consequently, we measured the scope of caffeine effectiveness in bees inoculated and uninoculated with IAPV by performing the same type of high-throughput bioassay across a wider range of caffeine concentrations. Our results indicate that caffeine may provide benefits that scale with concentration, though the exact mechanism by which caffeine ingestion improves survivorship remains uncertain. Caffeine therefore has the potential to act as an accessible and inexpensive method of treating viral infections, while also serving as a tool to further understanding of honey bee–virus interactions at a physiological and molecular level. Full article
(This article belongs to the Special Issue Honey Bee Nutrition)
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24 pages, 5558 KiB  
Article
Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae
by Marie-Paule Nawrot-Esposito, Aurélie Babin, Matthieu Pasco, Marylène Poirié, Jean-Luc Gatti and Armel Gallet
Insects 2020, 11(10), 697; https://doi.org/10.3390/insects11100697 - 13 Oct 2020
Cited by 17 | Viewed by 4635
Abstract
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is [...] Read more.
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes. Full article
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17 pages, 760 KiB  
Review
New Insights into Cockroach Control: Using Functional Diversity of Blattella germanica Symbionts
by Xiaoyuan Pan, Xuejun Wang and Fan Zhang
Insects 2020, 11(10), 696; https://doi.org/10.3390/insects11100696 - 13 Oct 2020
Cited by 16 | Viewed by 4758
Abstract
Insects have close symbiotic relationships with several microbes, which extends the limited metabolic networks of most insects. Using symbiotic microorganisms for the biological control of pests and insect-borne diseases has become a promising direction. Blattella germanica (L.) (Blattaria: Blattidae) is a public health [...] Read more.
Insects have close symbiotic relationships with several microbes, which extends the limited metabolic networks of most insects. Using symbiotic microorganisms for the biological control of pests and insect-borne diseases has become a promising direction. Blattella germanica (L.) (Blattaria: Blattidae) is a public health pest worldwide, which is difficult to control because of its strong reproductive ability, adaptability, and resistance to insecticides. In this paper, the diverse biological functions (nutrition, reproductive regulation, insecticide resistance, defense, and behavior) of symbionts were reviewed, and new biological control strategies on the basis of insect–symbiont interaction were proposed. We highlight new directions in B. germanica control, such as suppressing cockroach population using Wolbachia or paratransgenes, and combining fungal insecticides with synergistic agents to enhance insecticidal efficacy. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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17 pages, 1960 KiB  
Article
Effects of Aphid Density and Plant Taxa on Predatory Ladybeetle Abundance at Field and Landscape Scales
by Hongsheng Pan, Bing Liu, Coline C. Jaworski, Long Yang, Yongqiang Liu, Nicolas Desneux, Eva Thomine and Yanhui Lu
Insects 2020, 11(10), 695; https://doi.org/10.3390/insects11100695 - 13 Oct 2020
Cited by 13 | Viewed by 2719
Abstract
In agroecosystems, predatory ladybeetles play an important role in restraining aphid population growth and suppressing aphid populations. They can adapt to various habitats and make use of various aphid species associated with multiple host plants during their life cycle. Agricultural landscapes in China [...] Read more.
In agroecosystems, predatory ladybeetles play an important role in restraining aphid population growth and suppressing aphid populations. They can adapt to various habitats and make use of various aphid species associated with multiple host plants during their life cycle. Agricultural landscapes in China are composed of a mosaic of small fields with a diverse range of crops, and how ladybeetles make use of host plant diversity in such landscapes has rarely been documented. In this study, we examined the relationship between aphid densities and ladybeetle densities in two different settings: (i) on the majority of plant species (including crops, trees, and weeds) at a local field scale in 2013 and 2014, and (ii) in paired cotton and maize crop fields at a regional landscape scale in 2013. Overall, we found that aphid abundance determined predatory ladybeetle abundance at both the local field and landscape scales, and there was a positive correlation between aphid densities and ladybeetle densities. However, plant taxa had no significant influence on the predatory ladybeetle abundance at the local field scale. In addition, the effect of aphids on ladybeetles abundance was influenced by the crop type and growing season at the regional landscape scale. There was a significant positive correlation between aphids and ladybeetles populations on cotton only in July and August, whereas the correlation was significant for maize throughout the whole growing season. We also conducted an analysis of the stable carbon isotope ratios of the adult ladybeetles caught in cotton and maize fields (C3 and C4 crops, respectively) in a regional landscape-scale survey in 2013. The δ13Cvalue indicated that most prey aphids for ladybeetles originated from crops where aphids are abundant (cotton in June and July; both maize and cotton in August).These findings improved our understanding of the migration and dispersal of ladybeetles among different habitats and plant species and provided insight into the promotion of the regional conservation and pest control of natural enemies in northern China. Full article
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15 pages, 2411 KiB  
Article
Metarhizium Anisopliae Challenges Immunity and Demography of Plutella xylostella
by Junaid Zafar, Rana Fartab Shoukat, Yuxin Zhang, Shoaib Freed, Xiaoxia Xu and Fengliang Jin
Insects 2020, 11(10), 694; https://doi.org/10.3390/insects11100694 - 13 Oct 2020
Cited by 25 | Viewed by 6758
Abstract
Entomopathogenic fungi are naturally existing microbes, that can serve as a key regulator of insect pests in integrated pest management strategies. Besides having no hazardous effects on the environment, these entomopathogens are alternatives to synthetic insecticides that can control notorious insect-like Plutella xylostella [...] Read more.
Entomopathogenic fungi are naturally existing microbes, that can serve as a key regulator of insect pests in integrated pest management strategies. Besides having no hazardous effects on the environment, these entomopathogens are alternatives to synthetic insecticides that can control notorious insect-like Plutella xylostella, a destructive pest of cruciferous crops. Three different species of entomopathogenic fungi were evaluated before the selection (high larval mortality and least LC50) of Metarhizum anisopliae. The study was designed to investigate the mortality, development, and immune responses of P. xylostella when challenged with M. anisopliae, a naturally existing soil-borne entomopathogenic fungus. M. anisopliae resulted in high pest mortality by killing 93% of larvae. However, no statistically significant effect on hemocyte concentration was observed. The activity of enzymes (Phenoloxidase and Superoxide dismutase) and immune genes (Defensin, Spaetzle, Cecropin, Lysozyme, and Hemolin) did vary at different time points (24, 48, 72 and 96 h) after exposure to M. anisopliae. Disturbance in the biological cycles of P. xylostella was also detected, significantly shorter adult life span (8.11:6.87, M:F) and reduced fecundity (101 eggs/female) were observed along with disturbed larval and pupal duration. Results suggest that M. anisopliae can efficiently hinder the P. xylostella defense and developmental system, resulting in mortality and disturbed demography. Full article
(This article belongs to the Special Issue Biological Control and Insect Pathology)
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16 pages, 458 KiB  
Article
High-Throughput Genotyping of Common Chromosomal Inversions in the Afrotropical Malaria Mosquito Anopheles Funestus
by Martin Lukindu, R. Rebecca Love, Moussa W. Guelbeogo, Scott T. Small, Melissa T. Stephens, Nathan R. Campbell, N’Fale Sagnon, Carlo Costantini and Nora J. Besansky
Insects 2020, 11(10), 693; https://doi.org/10.3390/insects11100693 - 13 Oct 2020
Cited by 7 | Viewed by 2926
Abstract
Polymorphic chromosomal inversions have been implicated in local adaptation. In anopheline mosquitoes, inversions also contribute to epidemiologically relevant phenotypes such as resting behavior. Progress in understanding these phenotypes and their mechanistic basis has been hindered because the only available method for inversion genotyping [...] Read more.
Polymorphic chromosomal inversions have been implicated in local adaptation. In anopheline mosquitoes, inversions also contribute to epidemiologically relevant phenotypes such as resting behavior. Progress in understanding these phenotypes and their mechanistic basis has been hindered because the only available method for inversion genotyping relies on traditional cytogenetic karyotyping, a rate-limiting and technically difficult approach that is possible only for the fraction of the adult female population at the correct gonotrophic stage. Here, we focus on an understudied malaria vector of major importance in sub-Saharan Africa, Anopheles funestus. We ascertain and validate tag single nucleotide polymorphisms (SNPs) using high throughput molecular assays that allow rapid inversion genotyping of the three most common An. funestus inversions at scale, overcoming the cytogenetic karyotyping barrier. These same inversions are the only available markers for distinguishing two An. funestus ecotypes that differ in indoor resting behavior, Folonzo and Kiribina. Our new inversion genotyping tools will facilitate studies of ecotypic differentiation in An. funestus and provide a means to improve our understanding of the roles of Folonzo and Kiribina in malaria transmission. Full article
(This article belongs to the Collection Genomics and Cytogenetics of Mosquitoes)
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12 pages, 1300 KiB  
Article
The Bacterium Pantoea ananatis Modifies Behavioral Responses to Sugar Solutions in Honeybees
by Ricarda Scheiner, Sina Strauß, Markus Thamm, Gerard Farré-Armengol and Robert R. Junker
Insects 2020, 11(10), 692; https://doi.org/10.3390/insects11100692 - 12 Oct 2020
Cited by 4 | Viewed by 2474
Abstract
1. Honeybees, which are among the most important pollinators globally, do not only collect pollen and nectar during foraging but may also disperse diverse microbes. Some of these can be deleterious to agricultural crops and forest trees, such as the bacterium Pantoea ananatis [...] Read more.
1. Honeybees, which are among the most important pollinators globally, do not only collect pollen and nectar during foraging but may also disperse diverse microbes. Some of these can be deleterious to agricultural crops and forest trees, such as the bacterium Pantoea ananatis, an emerging pathogen in some systems. P. ananatis infections can lead to leaf blotches, die-back, bulb rot, and fruit rot. 2. We isolated P. ananatis bacteria from flowers with the aim of determining whether honeybees can sense these bacteria and if the bacteria affect behavioral responses of the bees to sugar solutions. 3. Honeybees decreased their responsiveness to different sugar solutions when these contained high concentrations of P. ananatis but were not deterred by solutions from which bacteria had been removed. This suggests that their reduced responsiveness was due to the taste of bacteria and not to the depletion of sugar in the solution or bacteria metabolites. Intriguingly, the bees appeared not to taste ecologically relevant low concentrations of bacteria. 4. Synthesis and applications. Our data suggest that honeybees may introduce P.ananatis bacteria into nectar in field-realistic densities during foraging trips and may thus affect nectar quality and plant fitness. Full article
(This article belongs to the Section Insect Behavior and Pathology)
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