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Insects
Volume 11
Issue 12
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Insects, Volume 11, Issue 12 (December 2020) – 70 articles

Cover Story (view full-size image): Bemisia tabaci MEAM1 is a serious agricultural pest worldwide. The Bemisia tabaci population’s diversity across large spatial scales has been extensively studied, but not in smaller spaces such as farmscapes. Thirty-five B. tabaci populations were collected from crop and non-crop species from fifteen farmscapes. Mitochondrial COI partial gene sequences (mtCOI) and six nuclear microsatellite markers were used to assess genetic diversity and genetic differentiation. Haplotype analysis using mtCOI sequences revealed the presence of a single B. tabaci MEAM1 haplotype across farmscapes. Microsatellite markers revealed no significant genetic structuring among populations corresponding to either plant species or farmscapes. Annual whitefly population explosions and subsequent dispersals across sampled farmscapes might have facilitated the persistence of a single panmictic B. tabaci population. View this pap
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15 pages, 2413 KiB  
Article
Non-Destructive Genotyping of Honeybee Queens to Support Selection and Breeding
by Jernej Bubnič, Katarina Mole, Janez Prešern and Ajda Moškrič
Insects 2020, 11(12), 896; https://doi.org/10.3390/insects11120896 - 21 Dec 2020
Cited by 5 | Viewed by 3271
Abstract
In traditional bee breeding, the honeybee queen is chosen for breeding based on the performance of the colony produced by its mother. However, we cannot be entirely certain that a specific queen will produce offspring with desirable traits until we observe the young [...] Read more.
In traditional bee breeding, the honeybee queen is chosen for breeding based on the performance of the colony produced by its mother. However, we cannot be entirely certain that a specific queen will produce offspring with desirable traits until we observe the young queen’s new colony. Collecting the queen’s genetic material enables quick and reliable determination of the relevant information. We sampled exuviae, feces, and wingtips for DNA extraction to avoid fatally injuring the queen when using tissue samples. Quantity and purity of extracted DNA were measured. Two mitochondrial markers were used to determine the lineage affiliation and exclude possible contamination of DNA extracts with non-honeybee DNA. dCAPS (derived Cleaved Amplified Polymorphic Sequences) markers allowed detection of single nucleotide polymorphisms (SNPs) in nuclear DNA regions presumably associated with Varroa sensitive hygiene and set the example of successful development of genotyping protocol from non-destructive DNA sources. One of the logical future steps in honeybee breeding is introducing genomic selection and non-destructive sampling methods of genetic material may be the prerequisite for successful genotyping. Our results demonstrate that the extraction of DNA from feces and exuviae can be introduced into practice. The advantage of these two sources over wingtips is reducing the time window for processing the samples, thus enabling genotyping directly after the queen’s emergence. Full article
(This article belongs to the Special Issue Honeybee Breeding)
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15 pages, 4700 KiB  
Article
Toxicity and Biological Effects of Beauveria brongniartii Fe0 Nanoparticles against Spodoptera litura (Fabricius)
by Jing Xu, Kaihui Zhang, Andrew G. S. Cuthbertson, Cailian Du and Shaukat Ali
Insects 2020, 11(12), 895; https://doi.org/10.3390/insects11120895 - 21 Dec 2020
Cited by 12 | Viewed by 2372
Abstract
Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe0 nanoparticles (Fe0 [...] Read more.
Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe0 nanoparticles (Fe0NPs) and their bio-efficacy against Spodoptera litura was observed during this study. Beauveria brongniartii conidia were coated with Fe0NPs and characterized by applying a selection of different analytical techniques. Ultraviolet (UV) spectroscopy showed the characteristic band of surface plasmon at 430 nm; Scanning electron microscopy (SEM) images showed spherical shaped nanoparticles with a size ranging between 0.41 to 0.80 µm; Energy-dispersive X-ray (EDX) spectral analysis revealed characteristic Fe peaks at 6.5 and 7.1 Kev; the X-ray diffractogram showed three strong peaks at 2θ values of 45.72°, 64.47°, and 84.05°. The bioassay studies demonstrated that mortality of 2nd instar S. litura larvae following Fe0NPs treatment increased with increasing concentrations of Fe0NPs at different time intervals. The median lethal concentration (LC50) values of Fe0NPs against S. litura after seven days of fungal treatment was 59 ppm, whereas median survival time (LT50) values for 200 and 500 ppm concentrations of Fe0NPs against S. litura seven days post-treatment were 5.1 and 2.29 days, respectively. Beauveria brongniartii-Fe0NPs caused significant reductions in feeding and growth parameters (relative growth rate, relative consumption rate, and efficiency of conversion of ingested food) of S. litura. Beauveria brongniartii Fe0NPs induced reduction in glutathione-S-transferase activities throughout the infection period whereas activities of antioxidant enzymes decreased during later periods of infection. These findings suggest that B. brongniartii Fe0NPs can potentially be used in biorational S. litura management programs. Full article
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12 pages, 8155 KiB  
Article
Flea Communities on Small Rodents in Eastern Poland
by Zbigniew Zając, Joanna Kulisz and Aneta Woźniak
Insects 2020, 11(12), 894; https://doi.org/10.3390/insects11120894 - 18 Dec 2020
Cited by 3 | Viewed by 2187
Abstract
Fleas are hematophagous insects infesting mainly small mammals and, less frequently, birds. With their wide range of potential hosts, fleas play a significant role in the circulation of pathogens in nature. Depending on the species, they can be vectors for viruses, bacteria, rickettsiae, [...] Read more.
Fleas are hematophagous insects infesting mainly small mammals and, less frequently, birds. With their wide range of potential hosts, fleas play a significant role in the circulation of pathogens in nature. Depending on the species, they can be vectors for viruses, bacteria, rickettsiae, and protozoa and a host for some larval forms of tapeworm species. The aim of this study was to determine the species composition of fleas and their small rodent host preferences in eastern Poland. Animals were captured in traps in various types of ecological habitats (a site covered by grassland vegetation within city limits, an unused agricultural meadow, and a fallow land near a mixed forest). The following rodent species were caught: Apodemus agrarius, Apodemus flavicollis, Microtus arvalis, and Myodesglareolus. Additionally, Ctenophthalmus agyrtes, Ctenophthalmus assimilis, Hystrichopsylla talpae, and Nosopsyllus fasciatus flea species were identified. The peak of the flea activity was noted in summer months. C. agyrtes was found to be the most abundant flea species in eastern Poland, while the greatest numbers of fleas were collected from the rodent species A. agrarius. Full article
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13 pages, 1711 KiB  
Article
Evidence for Divergent Selection on Immune Genes between the African Malaria Vectors, Anopheles coluzzii and A. gambiae
by Yoosook Lee, Lattha Souvannaseng, Travis C. Collier, Bradley J. Main, Laura C. Norris, Abdarahamane Fofana, Sekou F. Traoré, Anthony J. Cornel, Shirley Luckhart and Gregory C. Lanzaro
Insects 2020, 11(12), 893; https://doi.org/10.3390/insects11120893 - 18 Dec 2020
Cited by 2 | Viewed by 2637
Abstract
During their life cycles, microbes infecting mosquitoes encounter components of the mosquito anti-microbial innate immune defenses. Many of these immune responses also mediate susceptibility to malaria parasite infection. In West Africa, the primary malaria vectors are Anopheles coluzzii and A. gambiae sensu stricto, [...] Read more.
During their life cycles, microbes infecting mosquitoes encounter components of the mosquito anti-microbial innate immune defenses. Many of these immune responses also mediate susceptibility to malaria parasite infection. In West Africa, the primary malaria vectors are Anopheles coluzzii and A. gambiae sensu stricto, which is subdivided into the Bamako and Savanna sub-taxa. Here, we performed whole genome comparisons of the three taxa as well as genotyping of 333 putatively functional SNPs located in 58 immune signaling genes. Genome data support significantly higher differentiation in immune genes compared with a randomly selected set of non-immune genes among the three taxa (permutation test p < 0.001). Among the 58 genes studied, the majority had one or more segregating mutations (72.9%) that were significantly diverged among the three taxa. Genes detected to be under selection include MAP2K4 and Raf. Despite the genome-wide distribution of immune genes, a high level of linkage disequilibrium (r2 > 0.8) was detected in over 27% of SNP pairs. We discuss the potential role of immune gene divergence as adaptations to the different larval habitats associated with A. gambiae taxa and as a potential force driving ecological speciation in this group of mosquitoes. Full article
(This article belongs to the Special Issue A Tribute to Bill Black: Breakthroughs in Mosquito Vector Competence and Insecticide Resistance Research)
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14 pages, 1784 KiB  
Article
Testing Seven Hypotheses to Determine What Explains the Current Planthopper (Fulgoridae) Geographical and Species Richness Patterns in China
by Zheng-Xue Zhao, Lin Yang, Jian-Kun Long, Zhi-Min Chang, Zheng-Xiang Zhou, Yan Zhi, Liang-Jing Yang, Hong-Xing Li, Yong-Jin Sui, Nian Gong, Xiao-Ya Wang and Xiang-Sheng Chen
Insects 2020, 11(12), 892; https://doi.org/10.3390/insects11120892 - 17 Dec 2020
Cited by 8 | Viewed by 2098
Abstract
Although many hypotheses have been proposed to understand the mechanisms underlying large-scale richness patterns, the environmental determinants are still poorly understood, particularly in insects. Here, we tested the relative contributions of seven hypotheses previously proposed to explain planthopper richness patterns in China. The [...] Read more.
Although many hypotheses have been proposed to understand the mechanisms underlying large-scale richness patterns, the environmental determinants are still poorly understood, particularly in insects. Here, we tested the relative contributions of seven hypotheses previously proposed to explain planthopper richness patterns in China. The richness patterns were visualized at a 1° × 1° grid size, using 14,722 distribution records for 1335 planthoppers. We used ordinary least squares and spatial error simultaneous autoregressive models to examine the relationships between richness and single environmental variables and employed model averaging to assess the environmental variable relative roles. Species richness was unevenly distributed, with high species numbers occurring in the central and southern mountainous areas. The mean annual temperature change since the Last Glacial Maximum was the most important factor for richness patterns, followed by mean annual temperature and net primary productivity. Therefore, historical climate stability, ambient energy, and productivity hypotheses were supported strongly, but orogenic processes and geological isolation may also play a vital role. Full article
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15 pages, 1957 KiB  
Article
Functional Analysis of Odorant-Binding Proteins 12 and 17 from Wheat Blossom Midge Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae)
by Weining Cheng, Yudong Zhang, Jinlin Yu, Wei Liu and Keyan Zhu-Salzman
Insects 2020, 11(12), 891; https://doi.org/10.3390/insects11120891 - 17 Dec 2020
Cited by 2 | Viewed by 2137
Abstract
The wheat blossom midge Sitodiplosis mosellana, one of the most disastrous wheat pests, depends highly on olfactory cues to track suitable plants. To better understand the olfactory recognition mechanisms involved in host selection, in the present study we cloned two S. mosellana [...] Read more.
The wheat blossom midge Sitodiplosis mosellana, one of the most disastrous wheat pests, depends highly on olfactory cues to track suitable plants. To better understand the olfactory recognition mechanisms involved in host selection, in the present study we cloned two S. mosellana adult antenna-specific odorant binding protein (OBP) genes, SmosOBP12 and SmosOBP17, and evaluated bacterially expressed recombinant proteins for their selectivity and sensitivity for host wheat volatiles using the fluorescence-based ligand binding assay. The results showed that both SmosOBPs effectively bound alcohol, ester, ketone, and terpenoid compounds. Particularly, SmosOBP12 had significantly higher affinities (Ki < 10.5 μM) than SmosOBP17 (Ki2 > 0.1 μM) to 3-hexanol, 1-octen-3-ol, D-panthenol, 3-carene, (Z)-3-hexenylacetate, hexyl acetate, methyl salicylate, heptyl acetate, and ethyl heptanoate. Consistently, S. mosellana females were attracted to all these chemicals in a behavioral assay using Y-tube olfactometer. SmosOBP12 also bound aldehyde, but neither bound alkanes. Notably, SmosOBP12 exhibited strong affinity to ocimene (Ki = 8.2 μM) that repelled S. mosellana. SmosOBP17, however, was insensitive to this compound. Taken together, our results indicate that SmosOBP12 may play a greater role than SmosOBP17 in perceiving these biologically active plant volatiles. Full article
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12 pages, 1740 KiB  
Article
Seasonal Migrations of Pantala flavescens (Odonata: Libellulidae) in Middle Asia and Understanding of the Migration Model in the Afro-Asian Region Using Stable Isotopes of Hydrogen
by Sergey N. Borisov, Ivan K. Iakovlev, Alexey S. Borisov, Mikhail Yu. Ganin and Alexei V. Tiunov
Insects 2020, 11(12), 890; https://doi.org/10.3390/insects11120890 - 17 Dec 2020
Cited by 11 | Viewed by 4498
Abstract
In Middle Asia, the dragonfly Pantala flavescens makes regular seasonal migrations. In spring, sexually mature dragonflies (immigrants) arrive in this region for reproduction. Dragonflies of the aboriginal generation (residents) develop in about two months, and migrate south in autumn. Residents of Middle Asia [...] Read more.
In Middle Asia, the dragonfly Pantala flavescens makes regular seasonal migrations. In spring, sexually mature dragonflies (immigrants) arrive in this region for reproduction. Dragonflies of the aboriginal generation (residents) develop in about two months, and migrate south in autumn. Residents of Middle Asia have significantly lower δ2H values (−123.5 (SD 17.2)‰, n = 53) than immigrants (−64.4 (9.7)‰, n = 12), as well as aboriginal dragonfly species from Ethiopia (−47.9 (10.8)‰, n = 4) and the Sahel zone (−50.1 (15.5)‰, n = 11). Phenological data on P. flavescens in the Afro-Asian region and a comparison with published isotopic data on migratory insects from this region suggest that (i) the probable area of origin of P. flavescens immigrants is located in tropical parts of East Africa and/or the Arabian Peninsula and (ii) the autumn migration of Middle Asian residents to the south may also pass through the Indian Ocean. We assume that in the Afro-Asian region, there is an extensive migration circle of P. flavescens covering East Africa, Central Asia and the Indian subcontinent with a total length of more than 14,000 km. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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11 pages, 1980 KiB  
Article
Consuming Parasitized Aphids Alters the Life History and Decreases Predation Rate of Aphid Predator
by Jian-Feng Liu, Xiu-Qin Wang, Jacqueline R. Beggs, Hou-Ding Ou, Xiao-Fei Yu, Xiu-Xian Shen and Mao-Fa Yang
Insects 2020, 11(12), 889; https://doi.org/10.3390/insects11120889 - 17 Dec 2020
Cited by 1 | Viewed by 1726
Abstract
Intraguild predation interactions have substantial theoretical and practical implications for the dynamics of natural competitor populations used for biological control. Intraguild predation on parasitized aphids not only has a direct, negative effect on the parasitoid species, but it may indirectly influence the predator’s [...] Read more.
Intraguild predation interactions have substantial theoretical and practical implications for the dynamics of natural competitor populations used for biological control. Intraguild predation on parasitized aphids not only has a direct, negative effect on the parasitoid species, but it may indirectly influence the predator’s development, survival, reproduction and predation rates. In this study, we used two-sex life table theory, life table parameters and predation rates of Aphidoletes aphidimyza (Rondani) to compare when its populations fed on aphids (Myzus persicae Sulzer) (Hemiptera: Aphididae) that were either unparasitized or parasitized by Aphidius gifuensis (Ashmead) (Hymenoptera: Braconidae). Our results showed that individuals of A. aphidimyza were capable of completing their development and attaining maturity when they fed on parasitized aphids. Although feeding on parasitized aphids did not influence the survival rates of immature A. aphidimyza, it did significantly slow their development and extended their longevity, thereby reducing the fecundity and predation rates of A. aphidimyza. These findings may be pivotal for better understanding the sustained coexistence of predators with parasitoids in the biological control of aphids. Full article
(This article belongs to the Special Issue Biological Control and Insect Pathology)
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20 pages, 3096 KiB  
Communication
Biotic Threats to Cycas micronesica Continue to Expand to Complicate Conservation Decisions
by Benjamin E. Deloso, L. Irene Terry, Lee S. Yudin and Thomas E. Marler
Insects 2020, 11(12), 888; https://doi.org/10.3390/insects11120888 - 16 Dec 2020
Cited by 11 | Viewed by 2041
Abstract
Invasions of non-native species can threaten native biodiversity, and island ecosystems are ideal for studying these phenomena. In this article, first, we report on the invasive species that combine to threaten the island cycad Cycas micronesica by reviewing the history of previously reported [...] Read more.
Invasions of non-native species can threaten native biodiversity, and island ecosystems are ideal for studying these phenomena. In this article, first, we report on the invasive species that combine to threaten the island cycad Cycas micronesica by reviewing the history of previously reported invasions and providing an update of recent invasions. Then, we prioritize the threat status of each herbivore and the interactions among them. Plant damage was initiated in 2003─2005 by the non-native Aulacaspis yasumatsui Takagi armored scale, Erechthias sp. Meyrick leaf miner, and Luthrodes pandava Horsfield butterfly, which elicited unprecedented irruptions of the native Acalolepta marianarum Aurivillius stem borer and increased herbivory by feral pigs (Sus scrofa L.). The combined impact of these five consumers represents the greatest sustained threat to the cycad tree species. Mitigation of the damage caused by phytophagous non-native species is urgently needed to conserve this unique gymnosperm tree. Full article
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13 pages, 2343 KiB  
Article
Olive Production Threatened by a Resurgent Pest Liothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) in Southern Italy
by Gregorio Vono, Carmelo Peter Bonsignore, Gregorio Gullo and Rita Marullo
Insects 2020, 11(12), 887; https://doi.org/10.3390/insects11120887 - 16 Dec 2020
Cited by 11 | Viewed by 3200
Abstract
This study investigated a resurgence of Liothrips oleae Costa (Thysanoptera: Phlaeothripidae), an insect pest of olive crops, in a focal Southern Italian olive-producing area (Calabria Region). The young and adult olive thrips feed on the leaves and fruits of wild and cultivated olive [...] Read more.
This study investigated a resurgence of Liothrips oleae Costa (Thysanoptera: Phlaeothripidae), an insect pest of olive crops, in a focal Southern Italian olive-producing area (Calabria Region). The young and adult olive thrips feed on the leaves and fruits of wild and cultivated olive trees, producing distortions, necrosis, and premature dropping of fruit. In our study, organic and integrated olive groves were compared for two years in order to establish the relationship between leaf and fruit damage among olive groves managed under different phytosanitary conditions. Sampling techniques were used in order to collect and count leaves and fruits (on plants and dropped premature drupes) presenting symptoms of thrips’ feeding activity. The impact of the thrips was significant in all orchards, and the estimated damage level on drupes and leaves was higher in organic olive management in each year. A morphological description of the adult females of the species is provided, and the first molecular characterization of the Calabrian olive thrips population was performed by using three different genetic regions (cytochrome c oxidase subunit I (COI), 28S ribosomal subunit (28S), and internal transcribed spacer 2 (ITS2)). Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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15 pages, 17851 KiB  
Article
The Antennal Pathway of Dragonfly Nymphs, from Sensilla to the Brain
by Silvana Piersanti, Manuela Rebora, Gianandrea Salerno and Sylvia Anton
Insects 2020, 11(12), 886; https://doi.org/10.3390/insects11120886 - 16 Dec 2020
Cited by 5 | Viewed by 3169
Abstract
Dragonflies are hemimetabolous insects, switching from an aquatic life style as nymphs to aerial life as adults, confronted to different environmental cues. How sensory structures on the antennae and the brain regions processing the incoming information are adapted to the reception of fundamentally [...] Read more.
Dragonflies are hemimetabolous insects, switching from an aquatic life style as nymphs to aerial life as adults, confronted to different environmental cues. How sensory structures on the antennae and the brain regions processing the incoming information are adapted to the reception of fundamentally different sensory cues has not been investigated in hemimetabolous insects. Here we describe the antennal sensilla, the general brain structure, and the antennal sensory pathways in the last six nymphal instars of Libellula depressa, in comparison with earlier published data from adults, using scanning electron microscopy, and antennal receptor neuron and antennal lobe output neuron mass-tracing with tetramethylrhodamin. Brain structure was visualized with an anti-synapsin antibody. Differently from adults, the nymphal antennal flagellum harbors many mechanoreceptive sensilla, one olfactory, and two thermo-hygroreceptive sensilla at all investigated instars. The nymphal brain is very similar to the adult brain throughout development, despite the considerable differences in antennal sensilla and habitat. Like in adults, nymphal brains contain mushroom bodies lacking calyces and small aglomerular antennal lobes. Antennal fibers innervate the antennal lobe similar to adult brains and the gnathal ganglion more prominently than in adults. Similar brain structures are thus used in L. depressa nymphs and adults to process diverging sensory information. Full article
(This article belongs to the Collection Insect Sensory Biology)
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10 pages, 380 KiB  
Article
Effect of Nitrogen on Phosphine-Susceptible and -Resistant Populations of Stored Product Insects
by Maria K. Sakka, Fotini Gatzali, Vaios T. Karathanos and Christos G. Athanassiou
Insects 2020, 11(12), 885; https://doi.org/10.3390/insects11120885 - 15 Dec 2020
Cited by 15 | Viewed by 2187
Abstract
In this study, we evaluated nitrogen treatment on phosphine-resistant field and -susceptible laboratory populations of different stored product beetles. Nine trials were conducted in commercial nitrogen chambers with the O2 level set at 1.0%. Two different temperatures—i.e., 28 and 40 °C—and three [...] Read more.
In this study, we evaluated nitrogen treatment on phosphine-resistant field and -susceptible laboratory populations of different stored product beetles. Nine trials were conducted in commercial nitrogen chambers with the O2 level set at 1.0%. Two different temperatures—i.e., 28 and 40 °C—and three exposure intervals—i.e., 2.5, 3 and 9 d—were used in our tests. Adults of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae); the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae); and the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) were used in the trials. The insects were placed in vials with different commodities per species and population, and their mortality was measured after the termination of each trial. Then, the vials were kept in incubator chambers at 25 °C and 65% relative humidity for 65 d to measure progeny production. Complete parental mortality was observed in all cases for O. surinamensis and S. oryzae, but there was some survival for T. castaneum at 28 °C and 3 d of exposure. In general, progeny production was completely (100%) suppressed, with some exceptions for all species and populations. The results indicate that low oxygen is effective for all species tested, regardless of their resistance status to phosphine, and can be further adopted as an alternative method to mitigate resistance in stored product beetles. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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16 pages, 1762 KiB  
Article
Prior Experience with Food Reward Influences the Behavioral Responses of the Honeybee Apis mellifera and the Bumblebee Bombus lantschouensis to Tomato Floral Scent
by Hong Zhang, Shuang Shan, Shaohua Gu, Xinzheng Huang, Zibo Li, Adel Khashaveh and Yongjun Zhang
Insects 2020, 11(12), 884; https://doi.org/10.3390/insects11120884 - 14 Dec 2020
Cited by 7 | Viewed by 2514
Abstract
Bee responses to floral scent are usually influenced by both innate biases and prior experience. Honeybees are less attracted than bumblebees to tomato flowers. However, little is known about how tomato floral scent regulates the foraging behaviors of honeybees and bumblebees. In this [...] Read more.
Bee responses to floral scent are usually influenced by both innate biases and prior experience. Honeybees are less attracted than bumblebees to tomato flowers. However, little is known about how tomato floral scent regulates the foraging behaviors of honeybees and bumblebees. In this study, the foraging behaviors of the honeybee Apis mellifera and the bumblebee Bombus lantschouensis on tomato flowers in greenhouses were investigated. Whether the two bee species exhibit different responses to tomato floral scent and how innate biases and prior experience influence bee choice behavior were examined. In the greenhouses, honeybees failed to collect pollen from tomato flowers, and their foraging activities decreased significantly over days. Additionally, neither naïve honeybees nor naïve bumblebees showed a preference for tomato floral scent in a Y-tube olfactometer. However, foraging experience in the tomato greenhouses helped bumblebees develop a strong preference for the scent, whereas honeybees with foraging experience continued to show aversion to tomato floral scent. After learning to associate tomato floral scent with a sugar reward in proboscis extension response (PER) assays, both bee species exhibited a preference for tomato floral scent in Y-tube olfactometers. The findings indicated that prior experience with a food reward strongly influenced bee preference for tomato floral scent. Full article
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13 pages, 1213 KiB  
Article
Long Term Monitoring in Switzerland Reveals That Adalia bipunctata Strongly Declines in Response to Harmonia axyridis Invasion
by Marc Kenis, Saidou Nacambo, Johan Van Vlaenderen, Renate Zindel and René Eschen
Insects 2020, 11(12), 883; https://doi.org/10.3390/insects11120883 - 12 Dec 2020
Cited by 11 | Viewed by 3554
Abstract
A long-term monitoring was conducted at 40 sites in four different habitats in north-western Switzerland to observe changes in populations of native ladybirds, following the invasion of the Asian harlequin ladybird, Harmonia axyridis. From 2006 to 2017, the same trees and meadows [...] Read more.
A long-term monitoring was conducted at 40 sites in four different habitats in north-western Switzerland to observe changes in populations of native ladybirds, following the invasion of the Asian harlequin ladybird, Harmonia axyridis. From 2006 to 2017, the same trees and meadows were sampled at least seven times per year using standard protocols. On 15 broadleaved hedges, H. axyridis quickly became the dominant species, representing 60 to 80% of adult ladybirds collected. It was second in abundance at five pine (Pinus sylvestris) stands and was a minor component of the ladybird complex at five spruce (Picea abies) stands and in 15 meadows. This survey revealed the severe decline of Adalia bipunctata, which was the most abundant native ladybird on broadleaved trees in 2006–2009 and has almost disappeared since 2010. So far, other native ladybirds do not seem to decline significantly, including species occupying the same ecological niches as H. axyridis. The total number of aphidophagous ladybirds did not decline either, suggesting that the biological control function of ladybirds on aphids living in these habitats has not been affected by the arrival of H. axyridis. Recommendations are given to further assess the impact of H. axyridis on native ladybirds and aphids. Full article
(This article belongs to the Section Insect Ecology, Diversity and Conservation)
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35 pages, 3250 KiB  
Review
Coffee Berry Borer (Hypothenemus hampei), a Global Pest of Coffee: Perspectives from Historical and Recent Invasions, and Future Priorities
by Melissa A. Johnson, Claudia Patricia Ruiz-Diaz, Nicholas C. Manoukis and Jose Carlos Verle Rodrigues
Insects 2020, 11(12), 882; https://doi.org/10.3390/insects11120882 - 12 Dec 2020
Cited by 43 | Viewed by 14115
Abstract
Coffee berry borer (Hypothenemus hampei (Ferrari), CBB) has invaded nearly every coffee-producing country in the world, and it is commonly recognized as the most damaging insect pest of coffee. While research has been conducted on this pest in individual coffee-growing regions, new [...] Read more.
Coffee berry borer (Hypothenemus hampei (Ferrari), CBB) has invaded nearly every coffee-producing country in the world, and it is commonly recognized as the most damaging insect pest of coffee. While research has been conducted on this pest in individual coffee-growing regions, new insights may be gained by comparing and contrasting patterns of invasion and response across its global distribution. In this review, we explore the existing literature and focus on common themes in the invasion biology of CBB by examining (1) how it was introduced into each particular region and the response to its invasion, (2) flight activity and infestation patterns, (3) economic impacts, and (4) management strategies. We highlight research conducted over the last ten years in Hawaii as a case study for the development and implementation of an effective integrated pest management (IPM) program for CBB, and also discuss biosecurity issues contributing to incursion and establishment. Potential areas for future research in each of the five major components of CBB IPM (monitoring and sampling, cultural, biological, chemical, and physical controls) are also presented. Finally, we emphasize that outreach efforts are crucial to the successful implementation of CBB IPM programs. Future research programs should strive to include coffee growers as much as possible to ensure that management options are feasible and cost-effective. Full article
(This article belongs to the Special Issue Invasive Arthropod Pests)
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17 pages, 3308 KiB  
Article
Manual Sampling and Video Observations: An Integrated Approach to Studying Flower-Visiting Arthropods in High-Mountain Environments
by Marco Bonelli, Andrea Melotto, Alessio Minici, Elena Eustacchio, Luca Gianfranceschi, Mauro Gobbi, Morena Casartelli and Marco Caccianiga
Insects 2020, 11(12), 881; https://doi.org/10.3390/insects11120881 - 11 Dec 2020
Cited by 8 | Viewed by 3905
Abstract
Despite the rising interest in biotic interactions in mountain ecosystems, little is known about high-altitude flower-visiting arthropods. In particular, since the research in these environment can be limited or undermined by harsh conditions and logistical difficulties, it is mandatory to develop effective approaches [...] Read more.
Despite the rising interest in biotic interactions in mountain ecosystems, little is known about high-altitude flower-visiting arthropods. In particular, since the research in these environment can be limited or undermined by harsh conditions and logistical difficulties, it is mandatory to develop effective approaches that maximize possibilities to gather high-quality data. Here we compared two different methods, manual sampling and video observations, to investigate the interactions between the high-mountain arthropod community and flowers of Androsace brevis (Primulaceae), a vulnerable endemic alpine species with a short flowering period occurring in early season. We manually sampled flower-visiting arthropods according to the timed-observations method and recorded their activity on video. We assessed differences and effectiveness of the two approaches to estimate flower-visiting arthropod diversity and to identify potential taxa involved in A. brevis pollination. Both methods proved to be effective and comparable in describing the diversity of flower visitors at a high taxonomic level. However, with manual sampling we were able to obtain a fine taxonomic resolution for sampled arthropods and to evaluate which taxa actually carry A. brevis pollen, while video observations were less invasive and allowed us to assess arthropod behavior and to spot rare taxa. By combining the data obtained with these two approaches we could accurately identify flower-visiting arthropods, characterize their behavior, and hypothesize a role of Hymenoptera Apoidea and Diptera Brachycera in A. brevis pollination. Therefore, we propose integrating the two approaches as a powerful instrument to unravel interactions between flowering plants and associated fauna that can provide crucial information for the conservation of vulnerable environments such as high-mountain ecosystems. Full article
(This article belongs to the Collection Insects in Mountain Ecosystems)
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16 pages, 2439 KiB  
Article
Combining DL-Methionine and Bacillus thuringiensis Subspecies israelensis: Prospects for a Mosquito Larvicide
by Elise A. Richardson, Nicole O. Abruzzo, Caitlin E. Taylor, Bruce R. Stevens, James P. Cuda and Emma N. I. Weeks
Insects 2020, 11(12), 880; https://doi.org/10.3390/insects11120880 - 11 Dec 2020
Cited by 2 | Viewed by 2032
Abstract
Mosquito larvicides can reduce mosquito populations at the source, potentially decreasing biting rates and pathogen transmission. However, there is a growing need for mosquito larvicides that are environmentally sustainable. Bacillus thuringiensis subspecies israelensis (BTI) is a naturally occurring bacterium commonly used as a [...] Read more.
Mosquito larvicides can reduce mosquito populations at the source, potentially decreasing biting rates and pathogen transmission. However, there is a growing need for mosquito larvicides that are environmentally sustainable. Bacillus thuringiensis subspecies israelensis (BTI) is a naturally occurring bacterium commonly used as a larvicide to manage mosquito populations. Methionine is an essential amino acid that has demonstrated toxic properties against larval mosquitoes in laboratory experiments, while having minimal effects on non-target organisms. The goal of this study was to evaluate the potential for a novel combination larvicide by testing for compatibility between these two active ingredients. We began by determining the lethal concentration values (LCs) of BTI and DL-methionine against Anopheles quadrimaculatus Say and Aedes aegypti Linnaeus (Diptera: Culicidae) larvae. These bioassays were conducted in glass jars and mortality was observed 48 h post-treatment. We found that while DL-methionine was more toxic to An. quadrimaculatus than Ae. aegypti, the opposite was true for BTI. Then, we used these LCs to conduct bioassays with a combination of BTI and DL-methionine to determine the relationship between the two active ingredients when used against An. quadrimaculatus and Ae. aegypti larvae. The findings of this study demonstrate that BTI and DL-methionine have the potential to be complementary due to their additive properties at higher concentrations and effect levels when tested against An. quadrimaculatus. However, an antagonistic relationship was detected at the concentrations tested with Ae. aegypti. These results are encouraging and imply that a DL-methionine or BTI/DL-methionine combination larvicide could be used in management of Anopheles species. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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12 pages, 1764 KiB  
Article
Screening of Helicoverpa armigera Mobilome Revealed Transposable Element Insertions in Insecticide Resistance Genes
by Khouloud KLAI, Benoît CHÉNAIS, Marwa ZIDI, Salma DJEBBI, Aurore CARUSO, Françoise DENIS, Johann CONFAIS, Myriam BADAWI, Nathalie CASSE and Maha MEZGHANI KHEMAKHEM
Insects 2020, 11(12), 879; https://doi.org/10.3390/insects11120879 - 11 Dec 2020
Cited by 19 | Viewed by 4215
Abstract
The cotton bollworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an important pest of many crops that has developed resistance to almost all groups of insecticides used for its management. Insecticide resistance was often related to Transposable Element (TE) insertions near specific [...] Read more.
The cotton bollworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an important pest of many crops that has developed resistance to almost all groups of insecticides used for its management. Insecticide resistance was often related to Transposable Element (TE) insertions near specific genes. In the present study, we deeply retrieve and annotate TEs in the H. armigera genome using the Pipeline to Retrieve and Annotate Transposable Elements, PiRATE. The results have shown that the TE library consists of 8521 sequences representing 236,132 TE copies, including 3133 Full-Length Copies (FLC), covering 12.86% of the H. armigera genome. These TEs were classified as 46.71% Class I and 53.29% Class II elements. Among Class I elements, Short and Long Interspersed Nuclear Elements (SINEs and LINEs) are the main families, representing 21.13% and 19.49% of the total TEs, respectively. Long Terminal Repeat (LTR) and Dictyostelium transposable element (DIRS) are less represented, with 5.55% and 0.53%, respectively. Class II elements are mainly Miniature Inverted Transposable Elements (MITEs) (49.11%), then Terminal Inverted Repeats (TIRs) (4.09%). Superfamilies of Class II elements, i.e., Transib, P elements, CACTA, Mutator, PIF-harbinger, Helitron, Maverick, Crypton and Merlin, were less represented, accounting for only 1.96% of total TEs. In addition, we highlighted TE insertions in insecticide resistance genes and we successfully identified nine TE insertions belonging to RTE, R2, CACTA, Mariner and hAT superfamilies. These insertions are hosted in genes encoding cytochrome P450 (CyP450), glutathione S-transferase (GST), and ATP-binding cassette (ABC) transporter belonging to the G and C1 family members. These insertions could therefore be involved in insecticide resistance observed in this pest. Full article
(This article belongs to the Special Issue Recent Advances in the Understanding of Molecular Mechanisms of Resistance in Noctuid Pests)
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11 pages, 1135 KiB  
Article
Soil Surface-Trapping of Tomato Leaf-Miner Flies Emerging from Underground Pupae with a Simple Electrostatic Cover of Seedbeds in a Greenhouse
by Teruo Nonomura and Hideyoshi Toyoda
Insects 2020, 11(12), 878; https://doi.org/10.3390/insects11120878 - 11 Dec 2020
Cited by 7 | Viewed by 1861
Abstract
In the present study, an electrostatic apparatus for trapping adult tomato leaf miner flies (Liriomyza sativae) emerging from underground pupae at the surface of a seedbed in an organic greenhouse was developed. The apparatus consisted of insulated iron rods arranged in [...] Read more.
In the present study, an electrostatic apparatus for trapping adult tomato leaf miner flies (Liriomyza sativae) emerging from underground pupae at the surface of a seedbed in an organic greenhouse was developed. The apparatus consisted of insulated iron rods arranged in parallel at set intervals and linked to a voltage generator, which supplied a negative charge to the rods, as well as non-insulated grounded iron rods with the same configuration. The two layers of insulated and non-insulated iron rods were arrayed in parallel to form a static electric field between the layers. The electric field created a strong attractive force capable of capturing flies that entered the field. In a greenhouse assay, the apparatus was placed horizontally above a seedbed in a greenhouse and surveyed for its ability to capture adult flies emerging from pupae that were introduced onto the seedbed beneath the apparatus. The results revealed that the apparatus effectively trapped all adult flies that emerged from the pupae and that it functioned stably while continuously operated during the entire period of the experiment. Thus, our novel apparatus is a promising tool for the physical control of adult tomato leaf miners in the insecticide-independent cultivation of greenhouse tomatoes. Full article
(This article belongs to the Special Issue Insect Physical Control: Electric Field-Based Pest Management Approach)
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11 pages, 1255 KiB  
Article
Preliminary Evaluation of a Granite Rock Dust Product for Pest Herbivore Management in Field Conditions
by Nicoletta Faraone and N. Kirk Hillier
Insects 2020, 11(12), 877; https://doi.org/10.3390/insects11120877 - 11 Dec 2020
Cited by 5 | Viewed by 2986
Abstract
The effects of granite rock dust in dry and aqueous formulations were evaluated under field conditions for control of insect pests in different crop systems and ornamental plants. We tested efficacy of crop protection following foliar applications on lily, squash, and cabbage plants [...] Read more.
The effects of granite rock dust in dry and aqueous formulations were evaluated under field conditions for control of insect pests in different crop systems and ornamental plants. We tested efficacy of crop protection following foliar applications on lily, squash, and cabbage plants by evaluating subsequent pest damage, overall plant health, and quantity of crops produced over one season. Lily plants treated with dry and aqueous formulations of rock dust were subject to lower herbivore damage (>1% and 11% herbivory damage, respectively) when compared to the controls (30% herbivory damage). Treatment on cabbage was less effective to protect plants against herbivory damage, and no statistically significant differences were reported within treatments. The foliar applications (dry and aqueous formulations) had positive impacts on growth of squash fruit resulting in a 2.5-fold increase in size relative to the control squash fruit. These results support the potential field application of granite dust to protect ornamental plants against herbivory attack, and reveal an alternative positive effect of the silica-based product on plant growth and development. Full article
(This article belongs to the Special Issue Natural Substances against Insect Pests: Assets and Liabilities)
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12 pages, 2101 KiB  
Article
Effects of Enzymatic Hydrolysis on the Functional Properties, Antioxidant Activity and Protein Structure of Black Soldier Fly (Hermetia illucens) Protein
by Inayat Batish, Devon Brits, Pedro Valencia, Caio Miyai, Shamil Rafeeq, Yixiang Xu, Magdalini Galanopoulos, Edward Sismour and Reza Ovissipour
Insects 2020, 11(12), 876; https://doi.org/10.3390/insects11120876 - 09 Dec 2020
Cited by 28 | Viewed by 5602
Abstract
The effects of chemical protein extraction, and enzymatic hydrolysis with Alcalase, papain and pepsin, on the functional properties, antioxidant activity, amino acid composition and protein structure of black soldier fly (H. illucens) larval protein were examined. Alcalase hydrolysates had the highest [...] Read more.
The effects of chemical protein extraction, and enzymatic hydrolysis with Alcalase, papain and pepsin, on the functional properties, antioxidant activity, amino acid composition and protein structure of black soldier fly (H. illucens) larval protein were examined. Alcalase hydrolysates had the highest degree of hydrolysis (p < 0.05), with the highest hydrolysate and oil fraction yield (p < 0.05). Pepsin hydrolysates showed the lowest oil holding capacity (p < 0.05), whereas no significant differences were observed among other enzymes and protein concentrates (p > 0.05). The emulsifying stability and foam capacity were significantly lower in protein hydrolysates than protein concentrate (p < 0.05). The antioxidant activity of protein hydrolysates from protein concentrate and Alcalase was higher than that with papain and pepsin (p < 0.05), owing to the higher hydrophobic amino acid content. Raman spectroscopy indicated structural changes in protein α-helices and β-sheets after enzymatic hydrolysis. Full article
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16 pages, 2396 KiB  
Article
The Clicking Elateroidea from Chinese Mesozoic Deposits (Insecta, Coleoptera)
by Jyrki Muona, Huali Chang and Dong Ren
Insects 2020, 11(12), 875; https://doi.org/10.3390/insects11120875 - 09 Dec 2020
Cited by 14 | Viewed by 2205
Abstract
Recent molecular studies have suggested that the clicking beetle families Elateridae, Eucnemidae, Throscidae, and Cerophytidae evolved in the Jurassic and diversified in the Cretaceous. These studies paid little attention to fossils, using them only as dating tools. The identification of Elateridae fossils is [...] Read more.
Recent molecular studies have suggested that the clicking beetle families Elateridae, Eucnemidae, Throscidae, and Cerophytidae evolved in the Jurassic and diversified in the Cretaceous. These studies paid little attention to fossils, using them only as dating tools. The identification of Elateridae fossils is challenging, as external synapomorphies are not known for this family. Elateridae can be identified only as something not belonging to the other related families, all of which have diagnostic synapomorphies. Most subfamilies and tribes of Elateridae do possess definite diagnostic characters, however, making their identification feasible. We checked the 28 Elateridae described from Chinese Mesozoic deposits. Twelve were Elateridae, seven were Eucnemidae, and one was a Throscidae. Three species could be Eucnemidae, but showed aberrant characters. Five species could not be placed and may not belong to Elateroidea at all. On the basis of these results we suggest that all previously described Elateridae fossils should be re-checked. They should be searched for synapomorphies defining Eucnemidae, Throscidae, and Cerophytidae. If such characters are not present, a click beetle type of fossil can be placed in Elateroidae incertae sedis. The Mesozoic Chinese Elateridae fossils all belong to clades that do not exist today, whereas the Mesozoic Eucnemidae subfamilies are extant ones. This may be the source of the disagreement between Elateridae fossil age and datings based on molecular studies. One new combination was made: Desmatus ponomarenkoi (Chang, Kiretjshuk & Ren, 2009) NEW COMBINATION (= Paradesmatus ponomarenkoi Chang, Kirejtshuk & Ren, 2009). Full article
(This article belongs to the Section Insect Systematics, Phylogeny and Evolution)
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13 pages, 1365 KiB  
Article
Interspecific Mating Effects on Locomotor Activity Rhythms and Refractoriness of Aedes albopictus (Diptera: Culicidae) Females
by Thais de Souza Feitoza, Victor Henrique Ferreira-de-Lima, Daniel Cardoso Portela Câmara, Nildimar Alves Honório, L. Philip Lounibos and Tamara Nunes Lima-Camara
Insects 2020, 11(12), 874; https://doi.org/10.3390/insects11120874 - 09 Dec 2020
Cited by 6 | Viewed by 2057
Abstract
This study tests the hypotheses that the locomotor activity of Ae. albopictus females is not significantly altered by the presence of accessory gland (AG) extracts from conspecific and heterospecific males, and that Ae. albopictus females remain receptive to mating with conspecific males even [...] Read more.
This study tests the hypotheses that the locomotor activity of Ae. albopictus females is not significantly altered by the presence of accessory gland (AG) extracts from conspecific and heterospecific males, and that Ae. albopictus females remain receptive to mating with conspecific males even after receiving AG of Ae. aegypti males. Virgin Ae. albopictus females were injected with saline (control group), AG extracts of Ae. aegypti males (aegMAG) or AG extracts of Ae. albopictus males (albMAG). Locomotor activity was evaluated under 12 h of light and 12 h of darkness at 25 °C. All live Ae. albopictus females were subsequently exposed to conspecific males for 48 h, and their spermathecae were dissected for the presence of sperm. Females injected with aegMAG and albMAG showed significant decreases in total, diurnal and diurnal without lights-on Period activities. Females injected with aegMAG showed significant decreases in nocturnal and nocturnal without lights-off period activities. Females injected with albMAG showed significant decreases in lights-off activity. A total of 83% of Ae. albopictus females injected with aegMAG and 10% of females injected with albMAG were inseminated by conspecific males. These results, coupled with our previous paper on MAG and interspecific mating effects on female Ae. aegypti, demonstrate contrasting outcomes on locomotor activities and loss of sexual receptivity, both conspecific and heterospecific MAGs capable of sterilizing virgin Ae. aegypti, but only conspecific MAGs sterilizing Ae. albopictus, whereas locomotor activities were depressed in females of both species after heterospecific and conspecific injections or treatments. Full article
(This article belongs to the Special Issue Vector-Borne Diseases in a Changing World)
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34 pages, 1500 KiB  
Review
Geographical Distribution and Selection of European Honey Bees Resistant to Varroa destructor
by Yves Le Conte, Marina D. Meixner, Annely Brandt, Norman L. Carreck, Cecilia Costa, Fanny Mondet and Ralph Büchler
Insects 2020, 11(12), 873; https://doi.org/10.3390/insects11120873 - 08 Dec 2020
Cited by 36 | Viewed by 9944
Abstract
Developing resistance to the varroa mite in honey bees is a major goal for apicultural science and practice, the development of selection strategies and the availability of resistant stock. Here we present an extended literature review and survey of resistant populations and selection [...] Read more.
Developing resistance to the varroa mite in honey bees is a major goal for apicultural science and practice, the development of selection strategies and the availability of resistant stock. Here we present an extended literature review and survey of resistant populations and selection programs in the EU and elsewhere, including expert interviews. We illustrate the practical experiences of scientists, beekeepers, and breeders in search of resistant bees. We describe numerous resistant populations surviving without acaricide treatments, most of which developed under natural infestation pressure. Their common characteristics: reduced brood development; limited mite population growth; and low mite reproduction, may cause conflict with the interests of commercial beekeeping. Since environmental factors affect varroa mite resistance, particular honey bee strains must be evaluated under different local conditions and colony management. The resistance traits of grooming, hygienic behavior and mite reproduction, together with simple testing of mite population development and colony survival, are significant in recent selection programs. Advanced breeding techniques and genetic and physiological selection tools will be essential in the future. Despite huge demand, there is no well-established market for resistant stock in Europe. Moreover, reliable experience or experimental evidence regarding the resistance of stocks under different environmental and management conditions is still lacking. Full article
(This article belongs to the Special Issue Honeybee Breeding)
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12 pages, 1282 KiB  
Article
Network Centrality as an Indicator for Pollinator Parasite Transmission via Flowers
by Niels Piot, Guy Smagghe and Ivan Meeus
Insects 2020, 11(12), 872; https://doi.org/10.3390/insects11120872 - 08 Dec 2020
Cited by 15 | Viewed by 2765
Abstract
Parasites are important actors within ecosystems. However, a key aspect to unraveling parasite epidemiology is understanding transmission. The bee pollinator community harbors several multihost parasites, which have been shown to be able to spread between species via flowers. Hence the plant–pollinator network can [...] Read more.
Parasites are important actors within ecosystems. However, a key aspect to unraveling parasite epidemiology is understanding transmission. The bee pollinator community harbors several multihost parasites, which have been shown to be able to spread between species via flowers. Hence the plant–pollinator network can provide valuable information on the transmission of these parasites between species. Although several controlled experiments have shown that flowers function as a transmission hub for parasites, the link with the plant–pollinator network has rarely been addressed in the field. Here, one can hypothesize that the most central flowers in the network are more likely to enable parasite transmission between species. In this study, we test this hypothesis in three local plant–pollinator networks and show that the centrality of a plant in a weighted plant–pollinator network is a good predictor of the presence of multihost pollinator parasites on the plant’s flowers. Full article
(This article belongs to the Special Issue Honeybees and Wild Bees Health)
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12 pages, 1247 KiB  
Article
The Ant Who Cried Wolf? Short-Term Repeated Exposure to Alarm Pheromone Reduces Behavioral Response in Argentine Ants
by Jessica J. Maccaro, Brian A. Whyte and Neil D. Tsutsui
Insects 2020, 11(12), 871; https://doi.org/10.3390/insects11120871 - 08 Dec 2020
Cited by 3 | Viewed by 2504
Abstract
In this study we test whether Argentine ants (Linepithema humile) progressively reduce their response to a salient stimulus (alarm pheromone) with increased exposure over time. First, we used a two-chamber olfactometer to demonstrate three focal behaviors of Argentine ants that indicate [...] Read more.
In this study we test whether Argentine ants (Linepithema humile) progressively reduce their response to a salient stimulus (alarm pheromone) with increased exposure over time. First, we used a two-chamber olfactometer to demonstrate three focal behaviors of Argentine ants that indicate an alarmed state in response to conspecific alarm pheromone and pure synthetic iridomyrmecin (a dominant component of L. humile alarm pheromone). We then measured how these behaviors changed after repeated exposure to conspecific alarm pheromone from live ants. In addition, we investigate whether there is a difference in the ants’ behavioral response after “short” (3 min) versus “long” (6 min) intervals between treatments. Our results show that Argentine ants do exhibit reduced responses to their own alarm pheromone, temporarily ceasing their response to it after four or five exposures, and this pattern holds whether exposure is repeated after “short” or “long” intervals. We suggest alarm pheromones may be perceived as false alarms unless threatening stimuli warrant a continued state of alarm. These results should be kept in mind while developing pheromone-based integrated pest management strategies. Full article
(This article belongs to the Collection Biocontrol and Behavioral Approaches to Manage Invasive Insects)
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14 pages, 1673 KiB  
Article
A Multimodal Attract-and-Kill Device for the Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)
by Justin George, Stephen L. Lapointe, Larry T. Markle, Joseph M. Patt, Sandra A. Allan, Mamoudou Setamou, Monique J. Rivera, Jawwad A. Qureshi and Lukasz L. Stelinski
Insects 2020, 11(12), 870; https://doi.org/10.3390/insects11120870 - 08 Dec 2020
Cited by 12 | Viewed by 3413
Abstract
Phytophagous insects, including Asian citrus psyllids (Diaphorina citri Kuwayama), use multiple sensory modalities (vision, olfaction, and gustation,) to locate and accept host plants. We explored incorporation of several sensory cues into a multi-modal attract-and-kill device (AK device) using a three-dimensional shape to [...] Read more.
Phytophagous insects, including Asian citrus psyllids (Diaphorina citri Kuwayama), use multiple sensory modalities (vision, olfaction, and gustation,) to locate and accept host plants. We explored incorporation of several sensory cues into a multi-modal attract-and-kill device (AK device) using a three-dimensional shape to increase visibility, as well as elements of color, attractant, phagostimulant, UV reflectant, and toxicant. Attraction of adult D. citri to the device was mediated by a combination of a highly reflective yellow cylinder, a UV reflectant compound (magnesium oxide), and an odorant blend as a short-range attractant. The device surface was coated with a slow-release wax matrix (SPLAT™) augmented with a phagostimulant consisting of a 3-component blend (formic acid, acetic acid, and para-cymene) and an insecticide (β-cyfluthrin). Psyllids landing on the device attempted to feed from the wax matrix, became intoxicated, died, and fell from the device. The device remained fully active over a period of 12 weeks partly because dead psyllids or nontargets did not adhere to the surface as occurs on adhesive yellow sticky cards, the industry standard. Laboratory and field assays showed that the device attracted and killed significantly more adult D. citri than ordinary yellow sticky cards. This device or a future iteration based on the design elements of this device is expected to contribute to sustainable and environmentally appropriate management of D. citri by exploiting the psyllid’s innate behavioral responses to visual, olfactory, and gustatory stimuli. Full article
(This article belongs to the Section Insect Pest and Vector Management)
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17 pages, 6178 KiB  
Article
The Complete Mitochondrial Genome of Four Hylicinae (Hemiptera: Cicadellidae): Structural Features and Phylogenetic Implications
by Jiu Tang, Weijian Huang and Yalin Zhang
Insects 2020, 11(12), 869; https://doi.org/10.3390/insects11120869 - 07 Dec 2020
Cited by 10 | Viewed by 2150
Abstract
To reveal mtgenome characterizations and reconstruct phylogenetic relationships of Hylicinae, the complete mtgenomes of four hylicine species, including Nacolus tuberculatus, Hylica paradoxa, Balala fujiana, and Kalasha nativa, were sequenced and comparatively analyzed for the first time. We also carried out [...] Read more.
To reveal mtgenome characterizations and reconstruct phylogenetic relationships of Hylicinae, the complete mtgenomes of four hylicine species, including Nacolus tuberculatus, Hylica paradoxa, Balala fujiana, and Kalasha nativa, were sequenced and comparatively analyzed for the first time. We also carried out the richest (11) subfamily sampling of Cicadellidae to date, and reconstructed phylogenetic relationships of Membracoidea among 61 species based on three datasets using maximum likelihood and Bayesian inference analyses. All new sequenced mtgenomes are molecules ranging from 14,918 to 16,221 bp in length and are double stranded, circular in shape. The gene composition and arrangement of these mtgenomes are consistent with members of Membracoidea. Among 13 protein-coding genes, most show typical ATN start codons and TAR (TAA/TAG) or an incomplete stop codon T–, and several genes start by TTG/GTG. Results of the analysis for sliding window, nucleotide diversity, and nonsynonymous substitution/synonymous substitution indicate cox1 is a comparatively slower-evolving gene while atp8 is the fastest gene. In line with previous researches, phylogenetic results indicate that treehopper families are paraphyletic with respect to family Cicadellidae and also support the monophyly of all involved subfamilies including Hylicinae. Relationships among the four hylicine genera were recovered as (Hylica + (Nacolus + (Balala + Kalasha))). Full article
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13 pages, 1317 KiB  
Article
Susceptibility of Various Developmental Stages of the Fall Armyworm, Spodoptera frugiperda, to Entomopathogenic Nematodes
by Rajendra Acharya, Hwal-Su Hwang, Md Munir Mostafiz, Yeon-Su Yu and Kyeong-Yeoll Lee
Insects 2020, 11(12), 868; https://doi.org/10.3390/insects11120868 - 07 Dec 2020
Cited by 36 | Viewed by 4384
Abstract
The fall armyworm, Spodoptera frugiperda, which is native to Central and South America, has recently invaded Africa and Asia, causing serious damage to various crops. Although management to date has been largely unsuccessful, entomopathogenic nematodes (EPNs) are a potential biological control agent [...] Read more.
The fall armyworm, Spodoptera frugiperda, which is native to Central and South America, has recently invaded Africa and Asia, causing serious damage to various crops. Although management to date has been largely unsuccessful, entomopathogenic nematodes (EPNs) are a potential biological control agent that could be used to control the late larval and pupal stages of S. frugiperda that dwell under the ground. Here, we compared the virulence of seven EPNs against larval and pupal stages of S. frugiperda. In a Petri dish assay, both Heterorhabditis indica and Steinernema carpocapsae were highly virulent against younger larvae, whereas S. arenarium and S. longicaudum were highly virulent against older larvae. In contrast, H. bacteriophora, Heterorhabditis sp., and S. kushidai showed low virulence against all larval stages. In soil column and pot assays, H. indica, S. carpocapsae, and S. longicaudum were highly virulent against late larval and pupal stages compared with the other EPN species. Thus, H. indica, S. carpocapsae, and S. longicaudum are recommended for the biological control of S. frugiperda. Our study provides important information of EPNs for the practical application of biological control of fall armyworm. Full article
(This article belongs to the Collection Natural Enemies and Biological Control of Plant Pests)
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17 pages, 1351 KiB  
Article
Infection Patterns and Fitness Effects of Rickettsia and Sodalis Symbionts in the Green Lacewing Chrysoperla carnea
by Rebekka Sontowski, Michael Gerth, Sandy Richter, Axel Gruppe, Martin Schlegel, Nicole M. van Dam and Christoph Bleidorn
Insects 2020, 11(12), 867; https://doi.org/10.3390/insects11120867 - 07 Dec 2020
Cited by 1 | Viewed by 3071
Abstract
Endosymbionts are widely distributed in insects and can strongly affect their host ecology. The common green lacewing (Chrysoperla carnea) is a neuropteran insect which is widely used in biological pest control. However, their endosymbionts and their interactions with their hosts have [...] Read more.
Endosymbionts are widely distributed in insects and can strongly affect their host ecology. The common green lacewing (Chrysoperla carnea) is a neuropteran insect which is widely used in biological pest control. However, their endosymbionts and their interactions with their hosts have not been very well studied. Therefore, we screened for endosymbionts in natural and laboratory populations of Ch. carnea using diagnostic PCR amplicons. We found the endosymbiont Rickettsia to be very common in all screened natural and laboratory populations, while a hitherto uncharacterized Sodalis strain was found only in laboratory populations. By establishing lacewing lines with no, single or co-infections of Sodalis and Rickettsia, we found a high vertical transmission rate for both endosymbionts (>89%). However, we were only able to estimate these numbers for co-infected lacewings. Sodalis negatively affected the reproductive success in single and co-infected Ch. carnea, while Rickettsia showed no effect. We hypothesize that the fitness costs accrued by Sodalis infections might be more tolerable in the laboratory than in natural populations, as the latter are also prone to fluctuating environmental conditions and natural enemies. The economic and ecological importance of lacewings in biological pest control warrants a more profound understanding of its biology, which might be influenced by symbionts. Full article
(This article belongs to the Collection Insect Symbionts: Evolution and Application)
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