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Insects, Volume 11, Issue 1 (January 2020) – 67 articles

Cover Story (view full-size image): Honeybees have impressive capabilities for sensory orientation, learning and memory. They emerge into adult life in a colony of thousands of individuals. Young worker bees first perform tasks inside the dark hive for about three weeks before commencing foraging under bright sunlight. This drastic transition exposes bees to changing demands on spatial orientation, and profitable food sources must be explored in highly variable environments. Mushroom bodies are multisensory integration centers in the insect brain involved in learning and memory. They are particularly large in the honeybee (cover) and contain thousands of synaptic circuits with remarkable plasticity related to age, sensory experience and long-term memory. This review highlights the progress in understanding neuroplasticity in mushroom body microcircuits and its role in behavioral plasticity of this important social insect. View this paper
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14 pages, 776 KiB  
Article
Survival and Recovery of the Pine-Tree Lappet Dendrolimus pini When Subjected to Simulated Starvation
by Adrian Łukowski, Dawid Adamczyk and Piotr Karolewski
Insects 2020, 11(1), 67; https://doi.org/10.3390/insects11010067 - 20 Jan 2020
Cited by 7 | Viewed by 2928
Abstract
There are many reasons to study the survival and recovery of animals after starvation in simulated transport conditions or other passive dispersal methods. To do so, we chose Dendrolimus pini, an economically important pest of Scots pine with great potential in terms [...] Read more.
There are many reasons to study the survival and recovery of animals after starvation in simulated transport conditions or other passive dispersal methods. To do so, we chose Dendrolimus pini, an economically important pest of Scots pine with great potential in terms of passive dispersal outside its territory. In this work, we sought to answer the following questions: What is the maximum survival of different instar larvae after total starvation? Does access to dry tissues of the preferred host plant extend the lifespan of the larvae? Does the possibility of larvae recovery exist after starvation for various periods? We found that older larvae survived longer without food than younger larvae. Moreover, dry food did not extend the lifespan of the larvae. Our observations showed that insects were interested in food and tasted it at the beginning, but they did not feed on it for long. Furthermore, larvae recovery was indeed possible, and the time of starvation did not significantly affect this. We generally concluded that the D. pini larvae were characterized by the ability to survive without food for up to one month, which confirms that this species is able to survive long durations of transport to almost anywhere in the world. Full article
(This article belongs to the Special Issue Ecology and Management of Invasive Insects in Forest Ecosystems)
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21 pages, 2408 KiB  
Article
The Role of Annual Flowering Plant Strips on a Melon Crop in Central Spain. Influence on Pollinators and Crop
by Celeste Azpiazu, Pilar Medina, Ángeles Adán, Ismael Sánchez-Ramos, Pedro del Estal, Alberto Fereres and Elisa Viñuela
Insects 2020, 11(1), 66; https://doi.org/10.3390/insects11010066 - 20 Jan 2020
Cited by 18 | Viewed by 4199
Abstract
Planting flower strips adjacent to crops is among the habitat-management practices employed to offer alternative floral resources to pollinators. However, more information is needed to understand their potential spill-over of pollinators on nearby insect-pollinated crops. Over the course of two consecutive years, the [...] Read more.
Planting flower strips adjacent to crops is among the habitat-management practices employed to offer alternative floral resources to pollinators. However, more information is needed to understand their potential spill-over of pollinators on nearby insect-pollinated crops. Over the course of two consecutive years, the suitability of a flower mixture of 10 herbaceous plants for pollinators was evaluated on a weekly basis, in a randomized block design of two melon plots (10 × 10 m2) with or without 1 m-wide flower strips. Floral coverage and pollinator visits to the plant species, as well as pollinator visits and the yield and quality of the crop, were assessed. Additionally, the selected mixture was tested for 1 year in a commercial field in order to ascertain how far the flower strip could influence visitors in the crop. The most suitable species for a flower strip in central Spain based on their attractiveness, floral coverage and staggered blossom were Coriandrum sativum L., Diplotaxis virgata L., Borago officinalis L. and Calendula officinalis L. The flower strip can act as either pollinator competitor or facilitator to the crop, depending on their floral coverage and/or the predominant species during the crop bloom period. The concurrence of blooming of the rewarding plant C. officinalis with the melon crop should be avoided in our area. In the commercial field, the bee visitation rate in the melon flowers decreased with the distance to the flower strip. No influence of the specific flower strip evaluated on crop productivity or quality was found. Full article
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7 pages, 773 KiB  
Communication
Nest Modification Protects Immature Stages of the Japanese Orchard Bee (Osmia cornifrons) from Invasion of a Cleptoparasitic Mite Pest
by Neelendra K. Joshi, Kusum Naithani and David J. Biddinger
Insects 2020, 11(1), 65; https://doi.org/10.3390/insects11010065 - 20 Jan 2020
Cited by 5 | Viewed by 3695
Abstract
Osmia cornifrons (Radoszkowski) (Hymenoptera: Megachilidae) is an effective orchard pollinator. Considering the honey bee population decline in recent years, the conservation and propagation of O. cornifrons as an alternative managed pollinator is important in ensuring adequate pollination of tree fruit crops in the [...] Read more.
Osmia cornifrons (Radoszkowski) (Hymenoptera: Megachilidae) is an effective orchard pollinator. Considering the honey bee population decline in recent years, the conservation and propagation of O. cornifrons as an alternative managed pollinator is important in ensuring adequate pollination of tree fruit crops in the eastern United States. A field study was conducted to determine if nest modifications could reduce mite parasites and parasitoid natural enemies that attack managed O. cornifrons. Paraffin-coated paper liners (straws) were added to create modified nests, and were compared with the unmodified nests (i.e., nests without paper liners). In each nest, we recorded the number of nest cells with cleptoparasitic mites Chaetodactylus krombeini (Baker), and the presence of a parasitoid wasp Monodontomerus obscurus (Westwood). We also recorded the number of cocoons, male pupae, female pupae, and unconsumed pollen-nectar provision masses in these nests. Results showed that using paper liners in nest-tunnels greatly reduced the invasion of natural enemies of managed populations of O. cornifrons. Most notably, the addition of paper liners provided protection from invasion by C. krombeini mites, as the mean number of nest cells with mites were significantly lower in these lined nests compared to the nests without paper liners. A significantly higher number of male and female cocoons of O. cornifrons were recorded in the nests with paper liners. The population of M. obscurus was almost negligible in this field study. These results suggest that using nests with paper liners may accelerate the O. cornifrons population establishment and propagation in commercial orchards of rosaceous fruit crops, and possibly in other crops. Full article
(This article belongs to the Special Issue Stressors on Bee Health)
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19 pages, 3978 KiB  
Article
Mountains as Islands: Species Delimitation and Evolutionary History of the Ant-Loving Beetle Genus Panabachia (Coleoptera, Staphylinidae) from the Northern Andes
by Sofía I. Muñoz-Tobar and Michael S. Caterino
Insects 2020, 11(1), 64; https://doi.org/10.3390/insects11010064 - 20 Jan 2020
Cited by 5 | Viewed by 4283
Abstract
The ant-loving beetle genus Panabachia Park 1942 is a poorly studied beetle lineage from the new world tropics. We recently collected Panabachia from several previously unrecorded locations in the páramo biome of the high Ecuadorian Andes, with males exhibiting great morphological variation in [...] Read more.
The ant-loving beetle genus Panabachia Park 1942 is a poorly studied beetle lineage from the new world tropics. We recently collected Panabachia from several previously unrecorded locations in the páramo biome of the high Ecuadorian Andes, with males exhibiting great morphological variation in the distribution of the foveae and depressions in the pronotum, as well as aspects of the male genitalia. Here, we employ phylogenetic and species delimitation methods with mitochondrial (COI) and nuclear protein-coding (wingless) gene sequences to examine the concordance of morphological characters and geography with hypothesized species boundaries. Three methods of species delimitation (bPTP, GMYC and Stacey) were used to estimate the number of species, and divergence times between putative species using molecular clock calibration. Phylogenetic analysis revealed two parallel radiations, and species delimitation analyses suggest there are between 17 and 22 putative species. Based on clade support and concordance across species delimitation methods we hypothesize 17 distinct clusters, with allopatric speciation consistent with most geographic patterns. Additionally, a widespread species appears to be present in northern páramo sites, and some sister species sympatry may indicate other diversification processes have operated on certain lineages of Panabachia. Divergence time estimates suggest that Panabachia originated in the Miocene, but most species analyzed diverged during the Pliocene and Pleistocene (5.3–0.11 Mya), contemporaneous with the evolution of páramo plant species. Full article
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9 pages, 1374 KiB  
Article
Analysis of the Metaphase Chromosome Karyotypes in Imaginal Discs of Aedes communis, Ae. punctor, Ae. intrudens, and Ae. rossicus (Diptera: Culicidae) Mosquitoes
by Svetlana S. Alekseeva, Yulia V. Andreeva, Irina E. Wasserlauf, Anuarbek K. Sibataev and Vladimir N. Stegniy
Insects 2020, 11(1), 63; https://doi.org/10.3390/insects11010063 - 19 Jan 2020
Cited by 1 | Viewed by 2697
Abstract
In this study, cytogenetic analysis of the metaphase chromosomes from imaginal discs of Aedes (Diptera: Culicidae) mosquitoes—Aedes communis, Ae. punctor, Ae. intrudens, and Ae. rossicus—was performed. The patterns of C-banding and DAPI staining of the heteroсhromatin and the [...] Read more.
In this study, cytogenetic analysis of the metaphase chromosomes from imaginal discs of Aedes (Diptera: Culicidae) mosquitoes—Aedes communis, Ae. punctor, Ae. intrudens, and Ae. rossicus—was performed. The patterns of C-banding and DAPI staining of the heteroсhromatin and the length of the chromosomes demonstrate species specificity. In particular, the Ae. punctor chromosomes are the shortest compared with Ae. communis, Ae. intrudens, and Ae. rossicus, and they also carry additional C and DAPI bands in intercalary regions. The Ae. intrudens chromosomes are the longest, they have pericentromeric C bands, and they almost lack any DAPI bands near the centromere of chromosome 3 versus Ae. communis, which has the largest pericentromeric DAPI blocks in all three chromosome pairs. Ae. rossicus also possesses DAPI bands in the centromeric regions of all chromosomes, but their staining is weaker compared with those of Ae. communis. Therefore, the analysis of karyotypes is a tool for species-level identification of these mosquitoes. Full article
(This article belongs to the Collection Genomics and Cytogenetics of Mosquitoes)
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11 pages, 1341 KiB  
Review
Drosophila melanogaster Responses against Entomopathogenic Nematodes: Focus on Hemolymph Clots
by Alexis Dziedziech, Sai Shivankar and Ulrich Theopold
Insects 2020, 11(1), 62; https://doi.org/10.3390/insects11010062 - 19 Jan 2020
Cited by 14 | Viewed by 4033
Abstract
Several insect innate immune mechanisms are activated in response to infection by entomopathogenic nematodes (EPNs). In this review, we focus on the coagulation of hemolymph, which acts to stop bleeding after injury and prevent access of pathogens to the body cavity. After providing [...] Read more.
Several insect innate immune mechanisms are activated in response to infection by entomopathogenic nematodes (EPNs). In this review, we focus on the coagulation of hemolymph, which acts to stop bleeding after injury and prevent access of pathogens to the body cavity. After providing a general overview of invertebrate coagulation systems, we discuss recent findings in Drosophila melanogaster which demonstrate that clots protect against EPN infections. Detailed analysis at the cellular level provided insight into the kinetics of the secretion of Drosophila coagulation factors, including non-classical modes of secretion. Roughly, clot formation can be divided into a primary phase in which crosslinking of clot components depends on the activity of Drosophila transglutaminase and a secondary, phenoloxidase (PO)-dependent phase, characterized by further hardening and melanization of the clot matrix. These two phases appear to play distinct roles in two commonly used EPN infection models, namely Heterorhabditis bacteriophora and Steinernema carpocapsae. Finally, we discuss the implications of the coevolution between parasites such as EPNs and their hosts for the dynamics of coagulation factor evolution. Full article
(This article belongs to the Special Issue Insects, Nematodes and Their Symbiotic Bacteria)
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13 pages, 624 KiB  
Perspective
Proximate Drivers of Migration and Dispersal in Wing-Monomorphic Insects
by Mark K. Asplen
Insects 2020, 11(1), 61; https://doi.org/10.3390/insects11010061 - 18 Jan 2020
Cited by 7 | Viewed by 3383
Abstract
Gains in our knowledge of dispersal and migration in insects have been largely limited to either wing-dimorphic species or current genetic model systems. Species belonging to these categories, however, represent only a tiny fraction of insect biodiversity, potentially making generalization problematic. In this [...] Read more.
Gains in our knowledge of dispersal and migration in insects have been largely limited to either wing-dimorphic species or current genetic model systems. Species belonging to these categories, however, represent only a tiny fraction of insect biodiversity, potentially making generalization problematic. In this perspective, I present three topics in which current and future research may lead to greater knowledge of these processes in wing-monomorphic insects with limited existing molecular tools. First, threshold genetic models are reviewed as testable hypotheses for the heritability of migratory traits, using the sweet potato whitefly (Bemisia tabaci) as a case study of a behaviorally-polymorphic migratory species lacking morphological or physiological differentiation. In addition, both adaptive and non-adaptive explanations for the empirically variable relationship between egg production and flight in wing-monomorphic insects are discussed. Finally, with respect to the largest order of insects (Hymenoptera), the role of sex determination mechanisms for haplodiploidy as a driver for natal dispersal (for inbreeding avoidance) versus philopatry (such as in local mate competition) is discussed. Full article
(This article belongs to the Special Issue The Study of Insect Movement and Foraging Strategies)
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15 pages, 2931 KiB  
Article
High-Resolution Infection Kinetics of Entomopathogenic Nematodes Entering Drosophila melanogaster
by Alexis Dziedziech, Sai Shivankar and Ulrich Theopold
Insects 2020, 11(1), 60; https://doi.org/10.3390/insects11010060 - 18 Jan 2020
Cited by 13 | Viewed by 3416
Abstract
Entomopathogenic nematodes (EPNs) have been a useful model for studying wound healing in insects due to their natural mechanism of entering an insect host either through the cuticle or an orifice. While many experiments have shed light on nematode and host behavior, as [...] Read more.
Entomopathogenic nematodes (EPNs) have been a useful model for studying wound healing in insects due to their natural mechanism of entering an insect host either through the cuticle or an orifice. While many experiments have shed light on nematode and host behavior, as well as the host immune response, details regarding early nematode entry and proliferative events have been limited. Using high-resolution microscopy, we provide data on the early infection kinetics of Heterorhabditis bacteriophora and its symbiotic bacteria, Photorhabdus luminescens. EPNs appendage themselves to the host and enter through the host cuticle with a drill-like mechanism while leaving their outer sheath behind. EPNs immediately release their symbiotic bacteria in the host which leads to changes in host behavior and septicemia within 6 h while EPNs travel through the host in a predictable manner, congregating in the anterior end of the host. This paper sheds light on the entry and proliferative events of EPN infection, which will further aid in our understanding of wound healing and host immune activation at a high spatiotemporal resolution. Full article
(This article belongs to the Special Issue Insects, Nematodes and Their Symbiotic Bacteria)
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17 pages, 1185 KiB  
Article
Vegetation Pattern Modulates Ground Arthropod Diversity in Semi-Arid Mediterranean Steppes
by Fernando Meloni, Berta F. Civieta, Juan A. Zaragoza, María Lourdes Moraza and Susana Bautista
Insects 2020, 11(1), 59; https://doi.org/10.3390/insects11010059 - 18 Jan 2020
Cited by 23 | Viewed by 3776
Abstract
The ecological functioning of dryland ecosystems is closely related to the spatial pattern of the vegetation, which is typically structured in patches. Ground arthropods mediate key soil functions and ecological processes, yet little is known about the influence of dryland vegetation pattern on [...] Read more.
The ecological functioning of dryland ecosystems is closely related to the spatial pattern of the vegetation, which is typically structured in patches. Ground arthropods mediate key soil functions and ecological processes, yet little is known about the influence of dryland vegetation pattern on their abundance and diversity. Here, we investigate how patch size and cover, and distance between patches relate to the abundance and diversity of meso-and microarthropods in semi-arid steppes. We found that species richness and abundance of ground arthropods exponentially increase with vegetation cover, patch size, and patch closeness. The communities under vegetation patches mainly respond to patch size, while the communities in the bare-soil interpatches are mostly controlled by the average distance between patches, independently of the concurrent changes in vegetation cover. Large patches seem to play a critical role as reserve and source of ground arthropod diversity. Our results suggest that decreasing vegetation cover and/or changes in vegetation pattern towards small and over-dispersed vegetation patches can fast lead to a significant loss of ground arthropods diversity in drylands. Full article
(This article belongs to the Special Issue Elucidating the Role of Soil Arthropods in Soil Health)
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15 pages, 816 KiB  
Article
Genetic Diversity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Colonizing Sweet Potato and Cassava in South Sudan
by Beatrice C. Misaka, Everlyne N. Wosula, Philip W. Marchelo-d’Ragga, Trine Hvoslef-Eide and James P. Legg
Insects 2020, 11(1), 58; https://doi.org/10.3390/insects11010058 - 17 Jan 2020
Cited by 18 | Viewed by 4117
Abstract
Bemisia tabaci (Gennadius) is a polyphagous, highly destructive pest that is capable of vectoring viruses in most agricultural crops. Currently, information regarding the distribution and genetic diversity of B. tabaci in South Sudan is not available. The objectives of this study were to [...] Read more.
Bemisia tabaci (Gennadius) is a polyphagous, highly destructive pest that is capable of vectoring viruses in most agricultural crops. Currently, information regarding the distribution and genetic diversity of B. tabaci in South Sudan is not available. The objectives of this study were to investigate the genetic variability of B. tabaci infesting sweet potato and cassava in South Sudan. Field surveys were conducted between August 2017 and July and August 2018 in 10 locations in Juba County, Central Equatoria State, South Sudan. The sequences of mitochondrial DNA cytochrome oxidase I (mtCOI) were used to determine the phylogenetic relationships between sampled B. tabaci. Six distinct genetic groups of B. tabaci were identified, including three non-cassava haplotypes (Mediterranean (MED), Indian Ocean (IO), and Uganda) and three cassava haplotypes (Sub-Saharan Africa 1 sub-group 1 (SSA1-SG1), SSA1-SG3, and SSA2). MED predominated on sweet potato and SSA2 on cassava in all of the sampled locations. The Uganda haplotype was also widespread, occurring in five of the sampled locations. This study provides important information on the diversity of B. tabaci species in South Sudan. A comprehensive assessment of the genetic diversity, geographical distribution, population dynamics, and host range of B. tabaci species in South Sudan is vital for its effective management. Full article
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13 pages, 1838 KiB  
Article
The Parasitoid Eretmocerus hayati Is Compatible with Barrier Cropping to Decrease Whitefly (Bemisia tabaci MED) Densities on Cotton in China
by Xiaoming Zhang, Marco Ferrante, Fanghao Wan, Nianwan Yang and Gábor L. Lövei
Insects 2020, 11(1), 57; https://doi.org/10.3390/insects11010057 - 17 Jan 2020
Cited by 6 | Viewed by 2730
Abstract
The whitefly, Bemisia tabaci (Gennadius) cryptic species Mediterranean (MED), is a destructive insect pest worldwide. In order to contribute to controlling B. tabaci by non-chemical methods, we examined the possibility of using a combination of trap/barrier crops and a parasitoid natural enemy in [...] Read more.
The whitefly, Bemisia tabaci (Gennadius) cryptic species Mediterranean (MED), is a destructive insect pest worldwide. In order to contribute to controlling B. tabaci by non-chemical methods, we examined the possibility of using a combination of trap/barrier crops and a parasitoid natural enemy in cotton. We performed field experiments using cantaloupe (Cucumis melo) and sunflower (Helianthus annuus) as trap crops and maize (Zea mays) as a barrier crop combined with periodic releases of the parasitoid Eretmocerus hayati in Hebei Province, Northern China. All treatments significantly reduced immature whitefly densities. Parasitism rate was significantly higher in cotton plots intercropped with sunflower and with perimeter-planted cantaloupe. Adult whitefly density was negatively related to parasitoid abundance and was significantly lower in cotton plots intercropped with maize than in the control plots. Intercropping was more effective than perimeter-planting at reducing B. tabaci densities and increasing yield. Parasitoid dispersal was not hampered by barrier crops, indicating that the two methods of control are compatible. These results contribute to the development of integrated pest management methods against this important pest. Full article
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16 pages, 865 KiB  
Article
Importance of Antixenosis and Antibiosis Resistance to the Cabbage Whitefly (Aleyrodes proletella) in Brussels Sprout Cultivars
by Peter Hondelmann, Christina Paul, Monika Schreiner and Rainer Meyhöfer
Insects 2020, 11(1), 56; https://doi.org/10.3390/insects11010056 - 17 Jan 2020
Cited by 11 | Viewed by 3371
Abstract
The cabbage whitefly Aleyrodes proletella (L.) (Hemiptera: Aleyrodidae) is an important pest of a wide range of vegetable Brassicas. Since the control of this pest is still challenging, new approaches such as the use of resistant cultivars are required. For this, we screened [...] Read more.
The cabbage whitefly Aleyrodes proletella (L.) (Hemiptera: Aleyrodidae) is an important pest of a wide range of vegetable Brassicas. Since the control of this pest is still challenging, new approaches such as the use of resistant cultivars are required. For this, we screened 16 commercialised Brussels sprout cultivars for resistance against this species. Antibiosis was tested with no-choice experiments in a climate chamber, using reproduction, mortality, longevity, developmental time and weight as parameters. Antixenosis was screened in three choice experiments with circular design in a greenhouse to detect cultivar preferences. A field trial with both antibiosis and antixenosis tests was done to verify results under natural conditions. Finally, for several cultivars, also the leaf glucosinolate concentrations were analysed. Cabbage whiteflies showed on certain cultivars significantly increased mortality, prolonged developmental times and reduced weights. Besides, some cultivars were significantly less infested. However, the incidence of antibiosis and antixenosis as well as the glucosinolate patterns were partly inconsistent. Although a number of moderately resistant cultivars could be identified, the detected resistance is certainly not strong and consistent enough as an exclusive measure of a plant protection strategy but might become a component of a multi-layered strategy against cabbage whiteflies. Full article
(This article belongs to the Collection Integrated Pest Management Strategies for Horticultural Crops)
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16 pages, 250 KiB  
Article
Susceptibility of Myzus persicae, Brevicoryne brassicae and Nasonovia ribisnigri to Fungal Biopesticides in Laboratory and Field Experiments
by Gill Prince and Dave Chandler
Insects 2020, 11(1), 55; https://doi.org/10.3390/insects11010055 - 17 Jan 2020
Cited by 10 | Viewed by 3716
Abstract
The aim of this study was to evaluate the potential of entomopathogenic fungi (EPF) for the control of aphid pests of field vegetable crops. Four biopesticides based on the EPF Beauveria bassiana (Botanigard ES and Naturalis L), Cordyceps fumosorosea s.l. (Preferal WG), and [...] Read more.
The aim of this study was to evaluate the potential of entomopathogenic fungi (EPF) for the control of aphid pests of field vegetable crops. Four biopesticides based on the EPF Beauveria bassiana (Botanigard ES and Naturalis L), Cordyceps fumosorosea s.l. (Preferal WG), and Akanthomyces dipterigenus (Vertalec) were evaluated in a laboratory bioassay against peach-potato aphid Myzus persicae, cabbage aphid Brevicoryne brassicae, and currant-lettuce aphid Nasonovia ribisnigri. There was significant variation in the spore dose provided by the products, with Botanigard ES producing the highest dose (639 viable spores per mm2). Botanigard ES also caused more mortality than the other products. Combining Vertalec with the vegetable oil-based adjuvant Addit had an additive effect on the mortality of B. brassicae. All fungal products reduced the number of progeny produced by M. persicae but there was no effect with B. brassicae or N. ribisnigri. When aphid nymphs were treated with Botanigard ES and Preferal WG, both products reduced population development, with up to 86% reduction occurring for Botanigard ES against M. persicae. In a field experiment, Botanigard ES sprayed twice, at seven-day intervals, against B. brassicae on cabbage plants, reduced aphid numbers by 73%. In a second field experiment with B. brassicae, M. persicae, and N. ribisnigri, Botanigard ES reduced populations of B. brassicae and N. ribisnigri but there was no significant effect on M. persicae. Full article
(This article belongs to the Collection Integrated Pest Management Strategies for Horticultural Crops)
21 pages, 311 KiB  
Review
Soil Health and Arthropods: From Complex System to Worthwhile Investigation
by Cristina Menta and Sara Remelli
Insects 2020, 11(1), 54; https://doi.org/10.3390/insects11010054 - 16 Jan 2020
Cited by 95 | Viewed by 11190
Abstract
The dramatic increase in soil degradation in the last few decades has led to the need to identify methods to define not only soil quality but also, in a holistic approach, soil health. In the past twenty years, indices based on living communities [...] Read more.
The dramatic increase in soil degradation in the last few decades has led to the need to identify methods to define not only soil quality but also, in a holistic approach, soil health. In the past twenty years, indices based on living communities have been proposed alongside the already proven physical-chemical methods. Among them, some soil invertebrates have been included in monitoring programs as bioindicators of soil quality. Being an important portion of soil fauna, soil arthropods are involved in many soil processes such as organic matter decomposition and translocation, nutrient cycling, microflora activity regulation and bioturbation. Many studies have reported the use of soil arthropods to define soil quality; among taxa, some have been explored more in depth, typically Acari and Collembola, while generally less abundant groups, such as Palpigradi or Embioptera, have not been investigated much. This paper aims to evaluate and compare the use of different soil microarthropod taxa in soil degradation/quality studies to highlight which groups are the most reported for soil monitoring and which are the most sensitive to soil degradation. We have decided not to include the two most present and abundant taxa, Acari and Collembola, in this paper in consideration of the vast amount of existing literature and focus the discussion on the other microarthropod groups. We reported some studies for each taxon highlighting the use of the group as soil quality indicator. A brief section reporting some indices based on soil microarthropods is proposed at the end of this specific discussion. This paper can be considered as a reference point in the use of soil arthropods to estimate soil quality and health. Full article
(This article belongs to the Special Issue Elucidating the Role of Soil Arthropods in Soil Health)
14 pages, 2751 KiB  
Review
Using Nutritional Geometry to Explore How Social Insects Navigate Nutritional Landscapes
by Antonin J. J. Crumière, Calum J. Stephenson, Manuel Nagel and Jonathan Z. Shik
Insects 2020, 11(1), 53; https://doi.org/10.3390/insects11010053 - 15 Jan 2020
Cited by 10 | Viewed by 5979
Abstract
Insects face many cognitive challenges as they navigate nutritional landscapes that comprise their foraging environments with potential food items. The emerging field of nutritional geometry (NG) can help visualize these challenges, as well as the foraging solutions exhibited by insects. Social insect species [...] Read more.
Insects face many cognitive challenges as they navigate nutritional landscapes that comprise their foraging environments with potential food items. The emerging field of nutritional geometry (NG) can help visualize these challenges, as well as the foraging solutions exhibited by insects. Social insect species must also make these decisions while integrating social information (e.g., provisioning kin) and/or offsetting nutrients provisioned to, or received from unrelated mutualists. In this review, we extend the logic of NG to make predictions about how cognitive challenges ramify across these social dimensions. Focusing on ants, we outline NG predictions in terms of fundamental and realized nutritional niches, considering when ants interact with related nestmates and unrelated bacterial, fungal, plant, and insect mutualists. The nutritional landscape framework we propose provides new avenues for hypothesis testing and for integrating cognition research with broader eco-evolutionary principles. Full article
(This article belongs to the Special Issue Mechanisms of Nutritional Resource Exploitation by Insects)
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18 pages, 1497 KiB  
Review
Antiviral Effectors and Gene Drive Strategies for Mosquito Population Suppression or Replacement to Mitigate Arbovirus Transmission by Aedes aegypti
by Adeline E. Williams, Alexander W. E. Franz, William R. Reid and Ken E. Olson
Insects 2020, 11(1), 52; https://doi.org/10.3390/insects11010052 - 12 Jan 2020
Cited by 18 | Viewed by 6607
Abstract
The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed [...] Read more.
The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed as additional tools to combat arbovirus transmission. Genetic control of mosquitoes includes two basic strategies: population suppression and population replacement. The former aims to eliminate mosquito populations while the latter aims to replace wild populations with engineered, pathogen-resistant mosquitoes. In this review, we outline suppression strategies being applied in the field, as well as current antiviral effector genes that have been characterized and expressed in transgenic Ae. aegypti for population replacement. We discuss cutting-edge gene drive technologies that can be used to enhance the inheritance of effector genes, while highlighting the challenges and opportunities associated with gene drives. Finally, we present currently available models that can estimate mosquito release numbers and time to transgene fixation for several gene drive systems. Based on the recent advances in genetic engineering, we anticipate that antiviral transgenic Ae. aegypti exhibiting gene drive will soon emerge; however, close monitoring in simulated field conditions will be required to demonstrate the efficacy and utility of such transgenic mosquitoes. Full article
(This article belongs to the Special Issue Molecular Interactions of Viruses and Mosquitoes)
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28 pages, 9919 KiB  
Article
Molecular Phylogeny and Infraordinal Classification of Zoraptera (Insecta)
by Petr Kočárek, Ivona Horká and Robin Kundrata
Insects 2020, 11(1), 51; https://doi.org/10.3390/insects11010051 - 12 Jan 2020
Cited by 7 | Viewed by 7183
Abstract
Zoraptera is a small and predominantly tropical insect order with an unresolved higher classification due to the extremely uniform external body morphology. We, therefore, conducted a multigene molecular phylogeny of extant Zoraptera and critically re-evaluated their morphological characters in order to propose a [...] Read more.
Zoraptera is a small and predominantly tropical insect order with an unresolved higher classification due to the extremely uniform external body morphology. We, therefore, conducted a multigene molecular phylogeny of extant Zoraptera and critically re-evaluated their morphological characters in order to propose a natural infraordinal classification. We recovered a highly-resolved phylogeny with two main clades representing major evolutionary lineages in Zoraptera, for which we propose family ranks. The two families exhibit striking differences in male genitalia and reproductive strategies. Each family contains two subclades (subfamilies) supported by several morphological synapomorphies including the relative lengths of the basal antennomeres, the number and position of metatibial spurs, and the structure of male genitalia. The newly proposed higher classification of Zoraptera includes the family Zorotypidae stat. revid. with Zorotypinae Silvestri, 1913 (Zorotypus stat. revid., Usazoros Kukalova-Peck and Peck, 1993 stat. restit.) and Spermozorinae subfam. nov. (Spermozoros gen. nov.), and Spriralizoridae fam. nov. with Spiralizorinae subfam. nov. (Spiralizoros gen. nov., Scapulizoros gen. nov., Cordezoros gen. nov., Centrozoros Kukalova-Peck and Peck, 1993, stat. restit., Brazilozoros Kukalova-Peck and Peck, 1993, stat. restit.), and Latinozorinae subfam. nov. (Latinozoros Kukalova-Peck and Peck, 1993, stat. restit.). An identification key and morphological diagnoses for all supraspecific taxa are provided. Full article
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22 pages, 7681 KiB  
Article
Cost Assessment of Five Different Maize Grain Handling Techniques to Reduce Postharvest Losses from Insect Contamination
by Bernard Darfour and Kurt A. Rosentrater
Insects 2020, 11(1), 50; https://doi.org/10.3390/insects11010050 - 10 Jan 2020
Cited by 7 | Viewed by 3503
Abstract
Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading, and grain storage. Mechanized handling of grain in developing countries is rare, although the technology is effective against insects and pest infestations. The [...] Read more.
Farmers in developing nations encounter high postharvest losses mainly attributable to the lack of modern techniques for threshing, cleaning, grading, and grain storage. Mechanized handling of grain in developing countries is rare, although the technology is effective against insects and pest infestations. The objective was to evaluate the cost-effectiveness of five grain handling techniques that have the ability to reduce postharvest losses from insect infestation. The five methods were metal silo plus all accessories (m. silo + acc.), metal silo only (m. silo), woven polypropylene plus phosphine (w. PP. + Phos.), woven polypropylene only (w. PP.), and Purdue Improved Crop Storage bags only (PICS). The functional unit used was handling 1 kg of maize grain. The cost analysis of each technique was calculated based on equations using a spreadsheet. The annual capital and operational costs of handling using m. silo + acc. or m. silo were very high, unlike the PICS, w. PP. + Phos., or w. PP. The annual capital and operational costs decreased as production scale increased. Food security (due to reduced insects and pest infestations) and financial prospects of farmers can improve when the grain is mechanically handled with m. silo + acc. or m. silo. Full article
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13 pages, 2631 KiB  
Article
Comparative Analysis of the Diversity of the Microbial Communities between Non-Fertilized and Fertilized Eggs of Brown Planthopper, Nilaparvata lugens Stål
by Xuping Shentu, Yin Xiao, Yang Song, Zhenyan Cao, Jingxuan Fan and Xiaoping Yu
Insects 2020, 11(1), 49; https://doi.org/10.3390/insects11010049 - 10 Jan 2020
Cited by 9 | Viewed by 2401
Abstract
Yeast-like symbionts (YLSs), harbored in the abdominal fat body of brown planthoppers (BPHs), Nilaparvata lugens Stål, play an important role in the growth, development, and reproduction of their host. However, little is known about the diversity of the symbiotic fungal YLSs that are [...] Read more.
Yeast-like symbionts (YLSs), harbored in the abdominal fat body of brown planthoppers (BPHs), Nilaparvata lugens Stål, play an important role in the growth, development, and reproduction of their host. However, little is known about the diversity of the symbiotic fungal YLSs that are harbored in the eggs of BPHs and the difference between fertilized eggs and non-fertilized eggs. Here, we investigate the fungal community compositions of non-fertilized and fertilized eggs of BPHs and identified the YLSs in the hemolymph by qPCR. A total of seven phyla, 126 genera, and 158 species were obtained from all samples, and Ascomycota and Basidiomycota were the most predominant phyla in the non-fertilized and fertilized eggs. The richness index indicated that microbial diversity in the non-fertilized and fertilized eggs exhibited a profound difference. In addition, 11 strains were only identified in the fertilized eggs, and these strains provide new insights into the constitution of species in YLSs. The difference of Pichia guilliermondii in the female hemolymph indicated that fertilization affected the diversity in the eggs by changing the YLSs in the hemolymph. Our research provides a comprehensive understanding of YLS species and their abundance in the eggs of BPHs, and it primarily explores how the changes of YLSs in the hemolymph lead to this difference. Full article
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17 pages, 6791 KiB  
Article
Feeding Behavior of Asian Citrus Psyllid [Diaphorina citri (Hemiptera: Liviidae)] Nymphs and Adults on Common Weeds Occurring in Cultivated Citrus Described Using Electrical Penetration Graph Recordings
by Justin George, Ramdas Kanissery, El-Desouky Ammar, Itze Cabral, Larry T. Markle, Joseph M. Patt and Lukasz L. Stelinski
Insects 2020, 11(1), 48; https://doi.org/10.3390/insects11010048 - 10 Jan 2020
Cited by 18 | Viewed by 3937
Abstract
Asian citrus psyllid, Diaphorina citri, transmits Candidatus Liberibacter asiaticus (CLas), the putative causal agent of Huanglongbing disease. Although they primarily feed on the phloem of Citrus and related plants, when grove or host conditions are unfavorable, D. citri may [...] Read more.
Asian citrus psyllid, Diaphorina citri, transmits Candidatus Liberibacter asiaticus (CLas), the putative causal agent of Huanglongbing disease. Although they primarily feed on the phloem of Citrus and related plants, when grove or host conditions are unfavorable, D. citri may be able to use weed species as alternate food sources for survival. To explore this possibility, electrical penetration graph (EPG) recordings (18 h) were performed to investigate the feeding behavior of psyllid adults and nymphs on three common south Florida weeds (Bidens alba, Eupatorium capillifolium, and Ludwigia octovalvis). EPG recordings revealed that the proportion of time spent by D. citri feeding on xylem was similar on all tested weed species (19%–22%) and on the positive control (20%), the preferred host, Citrus macrophylla. Very little to no phloem feeding was observed on weed species by either nymphs or adults. Histological studies using epifluorescence microscopy showed that salivary sheaths were branched and extended into xylem of weed species, whereas they ended in phloem on citrus plants. No choice behavioral assays showed that adults can obtain some nutrition by feeding on weed species (xylem feeding) and they may be able to survive on them for short intervals, when host conditions are unfavorable. Full article
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10 pages, 927 KiB  
Article
Development of a Mycoinsecticide Bait Formulation for the Control of House Flies, Musca domestica L.
by Dalton Baker, Steven Rice, Diana Leemon, Rosamond Godwin and Peter James
Insects 2020, 11(1), 47; https://doi.org/10.3390/insects11010047 - 09 Jan 2020
Cited by 8 | Viewed by 4393
Abstract
The control of house flies, Musca domestica (L.), currently relies on the use of chemical insecticide spray and bait formulations. Entomopathogenic fungi, such as Metarhizium anisopliae, may provide an alternative to these products. This study aimed to develop and evaluate a mycoinsecticide [...] Read more.
The control of house flies, Musca domestica (L.), currently relies on the use of chemical insecticide spray and bait formulations. Entomopathogenic fungi, such as Metarhizium anisopliae, may provide an alternative to these products. This study aimed to develop and evaluate a mycoinsecticide bait formulation containing a virulent M. anisopliae isolate. Five M. anisopliae isolates were screened against M. domestica and isolate M16 was selected for bait development. Bait formulations containing a variety of additives, including (Z)-9-tricosene, were tested for their ability to increase fly visitation. A bait formulation containing M. anisopliae and skim milk powder was found to have the highest house fly visitation and was subsequently compared to a conventional chemical bait in an efficacy assay. The chemical bait (0.5% imidacloprid) caused faster mortality than the mycoinsecticide bait, however, similar levels of mortality were achieved by 4–5 days’ post exposure. These results suggest that M. anisopliae mycoinsecticide baits may offer an alternative to conventional chemical insecticides for the control of house flies in suitable areas. Full article
(This article belongs to the Special Issue Control of House Flies and Stable Flies)
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18 pages, 3716 KiB  
Article
A DNA Barcoding Survey of an Arctic Arthropod Community: Implications for Future Monitoring
by Mikko Pentinsaari, Gergin A. Blagoev, Ian D. Hogg, Valerie Levesque-Beaudin, Kate Perez, Crystal N. Sobel, Bryan Vandenbrink and Alex Borisenko
Insects 2020, 11(1), 46; https://doi.org/10.3390/insects11010046 - 09 Jan 2020
Cited by 15 | Viewed by 5391
Abstract
Accurate and cost-effective methods for tracking changes in arthropod communities are needed to develop integrative environmental monitoring programs in the Arctic. To date, even baseline data on their species composition at established ecological monitoring sites are severely lacking. We present the results of [...] Read more.
Accurate and cost-effective methods for tracking changes in arthropod communities are needed to develop integrative environmental monitoring programs in the Arctic. To date, even baseline data on their species composition at established ecological monitoring sites are severely lacking. We present the results of a pilot assessment of non-marine arthropod diversity in a middle arctic tundra area near Ikaluktutiak (Cambridge Bay), Victoria Island, Nunavut, undertaken in 2018 using DNA barcodes. A total of 1264 Barcode Index Number (BIN) clusters, used as a proxy for species, were recorded. The efficacy of widely used sampling methods was assessed. Yellow pan traps captured 62% of the entire BIN diversity at the study sites. When complemented with soil and leaf litter sifting, the coverage rose up to 74.6%. Combining community-based data collection with high-throughput DNA barcoding has the potential to overcome many of the logistic, financial, and taxonomic obstacles for large-scale monitoring of the Arctic arthropod fauna. Full article
(This article belongs to the Special Issue Polar Entomology)
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18 pages, 2147 KiB  
Article
Tracking Short-Range Attraction and Oviposition of European Grapevine Moths Affected by Volatile Organic Compounds in a Four-Chamber Olfactometer
by Anna Markheiser, Margit Rid, Sandra Biancu, Jürgen Gross and Christoph Hoffmann
Insects 2020, 11(1), 45; https://doi.org/10.3390/insects11010045 - 08 Jan 2020
Cited by 10 | Viewed by 3633
Abstract
The identification of volatile organic compounds (VOCs) leading to short-range attraction and oviposition of the European grapevine moth Lobesia botrana and European grape berry moth Eupoecilia ambiguella (Lepidoptera: Tortricidae) is crucial in order to establish bait-based decision support systems for control of these [...] Read more.
The identification of volatile organic compounds (VOCs) leading to short-range attraction and oviposition of the European grapevine moth Lobesia botrana and European grape berry moth Eupoecilia ambiguella (Lepidoptera: Tortricidae) is crucial in order to establish bait-based decision support systems for control of these pests. Therefore, we developed a method to measure the real-time behavioral response of female moths to VOCs using a four-chamber olfactometer coupled with a video tracking system. Ten synthetic VOCs were selected for this study: (S)-(−)-perillaldehyde, (E)/(Z)-linalool oxide, (±)-limonene, linalool, (E)-β-caryophyllene, α/β-farnesene, (−)-α-cedrene, methyl salicylate and cumene. The effect of VOCs on egg deposition was determined using a dual-choice oviposition test, whereas perception by female antennae was verified using electroantennography (EAG). During video tracking, females responded to volatile compounds emitted by grapevine with higher antennae and ovipositor activity than to air control. (E)/(Z)-linalool oxide, cumene and (S)-(−)-perillaldehyde released ovipositor activity of L. botrana, while the latter provoked oviposition. (R)/(S)-limonene affected ovipositor activity of E. ambiguella, whereas none of the VOCs tested attracted for oviposition. The results suggest that females have the ability to perceive specific VOCs by the antennae but also by the ovipositor, which could attract or repel for egg deposition. Full article
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12 pages, 1081 KiB  
Article
Evaluation of d-Limonene and β-Ocimene as Attractants of Aphytis melinus (Hymenoptera: Aphelinidae), a Parasitoid of Aonidiella aurantii (Hemiptera: Diaspididae) on Citrus spp.
by Khalid Mohammed, Manjree Agarwal, Beibei Li, James Newman, Tao Liu and Yonglin Ren
Insects 2020, 11(1), 44; https://doi.org/10.3390/insects11010044 - 08 Jan 2020
Cited by 20 | Viewed by 3626
Abstract
The volatile organic compounds (VOCs) released from herbivore-infested plants can be used as chemical signals by parasitoids during host location. In this research, we investigated the VOC chemical signals for the parasitoid Aphytis melinus to discriminate between Aonidiella aurantii (California red scale)-infested fruit [...] Read more.
The volatile organic compounds (VOCs) released from herbivore-infested plants can be used as chemical signals by parasitoids during host location. In this research, we investigated the VOC chemical signals for the parasitoid Aphytis melinus to discriminate between Aonidiella aurantii (California red scale)-infested fruit and non-infested fruit on three different citrus species. First, we identified the chemical stimuli emanating from non-infested and A. aurantii-infested citrus fruits via solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) analyses and identified 34 volatile organic compounds (VOCs). The GC-MS analysis showed qualitative and quantitative differences between VOCs emitted from non-infested and infested citrus fruit. Two VOCs, d-limonene and β-ocimene, were significantly increased in all infested fruit, regardless of the fruit species. The response of the female adult A. melinus to olfactory cues associated with A. aurantii infested fruit was evaluated using a Y-tube olfactometer. In two-choice behavioural assays, A. melinus females preferred infested citrus cues over non-infested fruit. Females showed positive chemotaxis toward these VOCs in all tested combinations involving two dosages of synthetic compounds, d-limonene and β-ocimene, except for d-limonene at a dosage of 10 μL/mL. The application of these VOCs may help to enhance the effectiveness of bio-control programs and parasitoid mass-rearing techniques. Full article
(This article belongs to the Special Issue Semiochemicals and Insect Behavior)
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17 pages, 1778 KiB  
Review
Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee
by Claudia Groh and Wolfgang Rössler
Insects 2020, 11(1), 43; https://doi.org/10.3390/insects11010043 - 07 Jan 2020
Cited by 31 | Viewed by 5958
Abstract
Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from [...] Read more.
Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from gustatory/tactile modalities. Behavioral plasticity following differential brood care, changes in sensory exposure or the formation of associative long-term memory (LTM) was shown to be associated with structural plasticity in synaptic microcircuits (microglomeruli) within olfactory and visual compartments of the MB calyx. In the same line, physiological studies have demonstrated that MB-calyx microcircuits change response properties after associative learning. The aim of this review is to provide an update and synthesis of recent research on the plasticity of microcircuits in the MB calyx of the honeybee, specifically looking at the synaptic connectivity between sensory projection neurons (PNs) and MB intrinsic neurons (Kenyon cells). We focus on the honeybee as a favorable experimental insect for studying neuronal mechanisms underlying complex social behavior, but also compare it with other insect species for certain aspects. This review concludes by highlighting open questions and promising routes for future research aimed at understanding the causal relationships between neuronal and behavioral plasticity in this charismatic social insect. Full article
(This article belongs to the Special Issue Honeybee Neurobiology and Behavior)
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14 pages, 3083 KiB  
Article
Aleurocanthus spiniferus (Hemiptera: Aleyrodidae) in Some European Countries: Diffusion, Hosts, Molecular Characterization, and Natural Enemies
by Francesco Nugnes, Stefania Laudonia, Giovanni Jesu, Maurice Gerardus Maria Jansen, Umberto Bernardo and Francesco Porcelli
Insects 2020, 11(1), 42; https://doi.org/10.3390/insects11010042 - 07 Jan 2020
Cited by 20 | Viewed by 5561
Abstract
After the first record in 2008 in Southeast Italy, the alien invasive and quarantine pest Aleurocanthus spiniferus (orange spiny whitefly—OSW) has gradually spread throughout Europe, infesting several new host plants in addition to the known hosts. Molecular characterization of some Italian populations and [...] Read more.
After the first record in 2008 in Southeast Italy, the alien invasive and quarantine pest Aleurocanthus spiniferus (orange spiny whitefly—OSW) has gradually spread throughout Europe, infesting several new host plants in addition to the known hosts. Molecular characterization of some Italian populations and a newly found Albanian population highlighted two different haplotypes invading Europe, belonging to one of the haplogroups previously recorded in China. A predator was recorded for the first time in several fields in Italy in association with OSW and other whitefly species. It was successively identified through a morpho-molecular characterization as a Nearctic member of the tribe Serangiini, the ladybird beetle, Delphastus catalinae. This predator represents a promising biocontrol agent to manage A. spiniferus outbreaks in Italy and other invaded countries. Full article
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13 pages, 1285 KiB  
Article
ColEval: Honeybee COLony Structure EVALuation for Field Surveys
by Julie Hernandez, Alban Maisonnasse, Marianne Cousin, Constance Beri, Corentin Le Quintrec, Anthony Bouetard, David Castex, Damien Decante, Eloïs Servel, Gerald Buchwalder, François Brunet, Estelle Feschet-Destrella, Kiliana de Bellescize, Guillaume Kairo, Léa Frontero, Miren Pédehontaa-Hiaa, Robin Buisson, Theo Pouderoux, Alexandre Aebi and André Kretzschmar
Insects 2020, 11(1), 41; https://doi.org/10.3390/insects11010041 - 05 Jan 2020
Cited by 16 | Viewed by 4879
Abstract
Methods for the evaluation and comparison of the structure of numerous honeybee colonies are needed for the development of applied and fundamental field research, as well as to evaluate how the structure and activity of honeybee colonies evolve over time. ColEval complements existing [...] Read more.
Methods for the evaluation and comparison of the structure of numerous honeybee colonies are needed for the development of applied and fundamental field research, as well as to evaluate how the structure and activity of honeybee colonies evolve over time. ColEval complements existing methods, as it uses an online reference image bank for (human) learning and training purposes. ColEval is based on the evaluation of the surface area percentage occupied by different components of a honeybee colony: adult worker bees, open and capped brood, honey, nectar, and pollen. This method is an essential tool for the description of the evolution in the size of honeybee colonies. The procedure makes allowances for tendencies between different observers and uses them to calculate accurate measurements of honeybee colony evaluation. ColEval thus allows for a posteriori comparison of under- or over-evaluation made by different observers working on the same project; it is thus possible to eliminate observer bias in the measurements and to conduct large surveys. Full article
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14 pages, 2675 KiB  
Article
Neuronal Innervation of the Subgenual Organ Complex and the Tibial Campaniform Sensilla in the Stick Insect Midleg
by Johannes Strauß
Insects 2020, 11(1), 40; https://doi.org/10.3390/insects11010040 - 04 Jan 2020
Cited by 11 | Viewed by 3925
Abstract
Mechanosensory organs in legs play are crucial receptors in the feedback control of walking and in the detection of substrate-borne vibrations. Stick insects serve as a model for the physiological role of chordotonal organs and campaniform sensilla. This study documents, by axonal tracing, [...] Read more.
Mechanosensory organs in legs play are crucial receptors in the feedback control of walking and in the detection of substrate-borne vibrations. Stick insects serve as a model for the physiological role of chordotonal organs and campaniform sensilla. This study documents, by axonal tracing, the neural innervation of the complex chordotonal organs and groups of campaniform sensilla in the proximal tibia of the midleg in Sipyloidea sipylus. In total, 6 nerve branches innervate the different sensory structures, and the innervation pattern associates different sensilla types by their position. Sensilla on the anterior and posterior tibia are innervated from distinct nerve branches. In addition, the variation in innervation is studied for five anatomical branching points. The most common variation is the innervation of the subgenual organ sensilla by two nerve branches rather than a single one. The fusion of commonly separated nerve branches also occurred. However, a common innervation pattern can be demonstrated, which is found in >75% of preparations. The variation did not include crossings of nerves between the anterior and posterior side of the leg. The study corrects the innervation of the posterior subgenual organ reported previously. The sensory neuroanatomy and innervation pattern can guide further physiological studies of mechanoreceptor organs and allow evolutionary comparisons to related insect groups. Full article
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11 pages, 1375 KiB  
Article
Larger is Better in the Parasitoid Eretmocerus warrae (Hymenoptera: Aphelinidae)
by Tao Wang and Michael A. Keller
Insects 2020, 11(1), 39; https://doi.org/10.3390/insects11010039 - 03 Jan 2020
Cited by 9 | Viewed by 2326
Abstract
Eretmocerus warrae (Hymenoptera: Aphelinidae) is a specialist parasitoid that is used for the control of the greenhouse whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). We investigated how temperature affects the body-size, life-time oviposition, and longevity of E. warrae at different stages of life. The body-sizes [...] Read more.
Eretmocerus warrae (Hymenoptera: Aphelinidae) is a specialist parasitoid that is used for the control of the greenhouse whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). We investigated how temperature affects the body-size, life-time oviposition, and longevity of E. warrae at different stages of life. The body-sizes of both this parasitoid and its host are influenced by temperature. Body-volume indices that reflect body-sizes fell by 47.7 % in T. vaporariorum compared with 57.6% in E. warrae when temperature increased from 20 to 32 °C. The life-time oviposition of female adults of E. warrae that grew at the immature developmental temperature of 20 °C was 86 ± 22 eggs, more than 66 ± 11 eggs at 26 °C, and 65 ± 23 eggs at 32 °C. Besides the influence on fecundity, temperature also influences the oviposition behaviour at the adult stage. More eggs were oviposited at 20 and 26 °C than at 32 °C. Higher temperatures reduced survival in the immature developmental stages and longevity in adults. Adult females lived for a maximum of 8.9 ± 1.8 days at 20 °C and laid a maximum of 97.4 ± 23.2 eggs when reared at 20 °C and maintained at 26 °C as adults. Adult body-size is positively correlated with life-time oviposition but not adult longevity. The results imply that temperature influences the nature of interactions between a parasitoid and its host. Larger wasps can live longer and parasitise more hosts, which should improve their performance as biological control agents. Full article
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22 pages, 534 KiB  
Review
Pest Management Challenges and Control Practices in Codling Moth: A Review
by Martina Kadoić Balaško, Renata Bažok, Katarina M. Mikac, Darija Lemic and Ivana Pajač Živković
Insects 2020, 11(1), 38; https://doi.org/10.3390/insects11010038 - 03 Jan 2020
Cited by 48 | Viewed by 6603
Abstract
The codling moth, Cydia pomonella L., is a serious insect pest in pome fruit production worldwide with a preference for apple. The pest is known for having developed resistance to several chemical groups of insecticides, making its control difficult. The control and management [...] Read more.
The codling moth, Cydia pomonella L., is a serious insect pest in pome fruit production worldwide with a preference for apple. The pest is known for having developed resistance to several chemical groups of insecticides, making its control difficult. The control and management of the codling moth is often hindered by a lack of understanding about its biology and ecology, including aspects of its population genetics. This review summarizes the information about the origin and biology of the codling moth, describes the mechanisms of resistance in this pest, and provides an overview of current research of resistant pest populations and genetic research both in Europe and globally. The main focus of this review is on non-pesticide control measures and anti-resistance strategies which help to reduce the number of chemical pesticides used and their residues on food and the local environment. Regular monitoring for insecticide resistance is essential for proactive management to mitigate potential insecticide resistance. Here we describe techniques for the detection of resistant variants and possibilities for monitoring resistance populations. Also, we present our present work on developing new methods to maintain effective control using appropriate integrated resistance management (IRM) strategies for this economically important perennial pest. Full article
(This article belongs to the Special Issue Monitoring and Detection of Insect Resistance)
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