Next Issue
Volume 11, April
Previous Issue
Volume 11, February

Insects, Volume 11, Issue 3 (March 2020) – 62 articles

Cover Story (view full-size image): The UV part of the solar spectrum plays an important role in the ecological behavior of insects, including orientation, navigation, feeding, and interaction between the sexes. The manipulation of the UV vision of insects using UV-blocking materials has been effective in preventing the immigration of insect pests from the external environment into the protected crop. Several studies indicate that these covers can sustain the activity of biocontrol agents such as parasitoids. However, little information is known about their effect on predator insects. In this work, we study the effect of UV-absorbing nets on the commercially available hoverfly Sphaerophoria rueppellii Wiedemann (Diptera: Syrphidae). The results strongly suggest that the use of photoselective nets and the release of syrphid predators are compatible strategies to be used in IPM aphid-control programs. View this paper.
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Order results
Result details
Select all
Export citation of selected articles as:
Article
Evaluation of the Field Efficacy of Heterorhabditis Bacteriophora Poinar (Rhabditida: Heterorhabditidae) and Synthetic Insecticides for the Control of Western Corn Rootworm Larvae
Insects 2020, 11(3), 202; https://doi.org/10.3390/insects11030202 - 24 Mar 2020
Cited by 7 | Viewed by 1067
Abstract
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May and its three instars feed intensively on maize roots [...] Read more.
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May and its three instars feed intensively on maize roots in June, causing plant lodging that leads to a loss of economic yield. A three-year field experiment (2016–2018) was conducted to compare the effectiveness i) of soil-applied granular insecticide based on the active ingredient tefluthrin, ii) of maize seeds dressed with thiacloprid, and iii) entomopathogenic nematodes Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae, product Dianem) against WCR larvae. An additional treatment with alcohol ethoxylate (i.e., soil conditioner) mixed with entomopathogenic nematodes was performed in 2017 and 2018 to check for any increase of entomopathogenic nematodes’ effectiveness. Field tests were carried out in two fields infested naturally with a WCR pest population, one in Bučečovci (Eastern Slovenia) and the other in Šmartno pri Cerkljah (northern Slovenia), exhibiting dissimilar pedo-climatic conditions and soil pest densities. The treatments were performed in five replicates per experiment in each year. The efficacy of the treatments was very similar at both locations, despite the approximately five-fold lower WCR soil pest densities in northern than in eastern Slovenia, as well as being constant over time. The largest number of WCR beetles was observed in the negative control, followed by that of beetles subjected to thiacloprid treatment (insignificant decrease taking into account the entire three-year dataset). Treatments with tefluthrin (44.1 ± 11.7%), H. bacteriophora (46.2 ± 7.4%), and H. bacteriophora + alcohol ethoxylate (49.2 ± 1.8%) significantly decreased the numbers of emerging beetles. Treatments of thiacloprid, H. bacteriophora, and H. bacteriophora + alcohol ethoxylate additionally led to significantly increased maize plant weights. Furthermore, entomopathogenic nematodes were able to persist in maize fields for almost five months at both experimental locations in silty and sandy loam soils. It was concluded that the control of WCR larvae in maize using the entomopathogenic nematode H. bacteriophora is as effective as a tefluthrin treatment, and could thus offer a sustainable Diabrotica v. virgifera biological control management option in Europe. Full article
(This article belongs to the Special Issue Insects, Nematodes and Their Symbiotic Bacteria)
Show Figures

Figure 1

Article
Blood Digestion by Trypsin-Like Serine Proteases in the Replete Lyme Disease Vector Tick, Ixodes scapularis
Insects 2020, 11(3), 201; https://doi.org/10.3390/insects11030201 - 23 Mar 2020
Cited by 4 | Viewed by 1838
Abstract
Ixodes scapularis is the major vector of Lyme disease in the Eastern United States. Each active life stage (larva, nymph, and adult) takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). [...] Read more.
Ixodes scapularis is the major vector of Lyme disease in the Eastern United States. Each active life stage (larva, nymph, and adult) takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). This protein-rich blood meal is the only food taken by Ixodes ticks and therefore efficient blood digestion is critical for survival. Studies in partially engorged ticks have shown that the initial stages of digestion are carried out by cathepsin proteases within acidic digestive cells. In this study, we investigated the potential role of serine proteases in blood digestion in replete ticks. RNA interference was used for functional analysis and a trypsin-benzoyl-D, L-arginine 4-nitoanilide assay was used to measure active trypsin levels. Hemoglobinolytic activity was determined in vitro, with or without a serine protease inhibitor. Our data suggest that trypsin levels increase significantly after repletion. Knockdown of serine proteases negatively impacted blood feeding, survival, fecundity, levels of active trypsin in the midgut, and resulted in lower hemoglobin degradation. Incubation of midgut extract with a trypsin inhibitor resulted in 65% lower hemoglobin degradation. We provide evidence of the serine proteases as digestive enzymes in fully engorged, replete females. Understanding the digestive profile of trypsin during blood meal digestion in I. scapularis improves our understanding of the basic biology of ticks and may lead to new methods for tick control. Full article
(This article belongs to the Special Issue Vectors and Vector-borne Diseases)
Show Figures

Graphical abstract

Article
Nest Site Selection during Colony Relocation in Yucatan Peninsula Populations of the Ponerine Ants Neoponera villosa (Hymenoptera: Formicidae)
Insects 2020, 11(3), 200; https://doi.org/10.3390/insects11030200 - 23 Mar 2020
Viewed by 1073
Abstract
In the Yucatan Peninsula, the ponerine ant Neoponera villosa nests almost exclusively in tank bromeliads, Aechmea bracteata. In this study, we aimed to determine the factors influencing nest site selection during nest relocation which is regularly promoted by hurricanes in this area. Using [...] Read more.
In the Yucatan Peninsula, the ponerine ant Neoponera villosa nests almost exclusively in tank bromeliads, Aechmea bracteata. In this study, we aimed to determine the factors influencing nest site selection during nest relocation which is regularly promoted by hurricanes in this area. Using ants with and without previous experience of Ae. bracteata, we tested their preference for refuges consisting of Ae. bracteata leaves over two other bromeliads, Ae. bromeliifolia and Ananas comosus. We further evaluated bromeliad-associated traits that could influence nest site selection (form and size). Workers with and without previous contact with Ae. bracteata significantly preferred this species over others, suggesting the existence of an innate attraction to this bromeliad. However, preference was not influenced by previous contact with Ae. bracteata. Workers easily discriminated between shelters of Ae. bracteata and A. comosus, but not those of the closely related Ae. bromeliifolia. In marked contrast, ants discriminated between similar sized Ae. bracteata and Ae. bromeliifolia plants, suggesting that chemical cues and plant structure play an important role. Size was also significant as they selected the largest plant when provided two dissimilar Ae. bracteata plants. Nest site selection by N. villosa workers seems to depend on innate preferences but familiarization with plant stimuli is not excluded. Full article
(This article belongs to the Special Issue Insects-Environment Interaction)
Show Figures

Graphical abstract

Article
Screening of Differentially Expressed Microsporidia Genes from Nosema ceranae Infected Honey Bees by Suppression Subtractive Hybridization
Insects 2020, 11(3), 199; https://doi.org/10.3390/insects11030199 - 22 Mar 2020
Viewed by 1077
Abstract
The microsporidium Nosema ceranae is a high prevalent parasite of the European honey bee (Apis mellifera). This parasite is spreading across the world into its novel host. The developmental process, and some mechanisms of N. ceranae-infected honey bees, has been [...] Read more.
The microsporidium Nosema ceranae is a high prevalent parasite of the European honey bee (Apis mellifera). This parasite is spreading across the world into its novel host. The developmental process, and some mechanisms of N. ceranae-infected honey bees, has been studied thoroughly; however, few studies have been carried out in the mechanism of gene expression in N. ceranae during the infection process. We therefore performed the suppressive subtractive hybridization (SSH) approach to investigate the candidate genes of N. ceranae during its infection process. All 96 clones of infected (forward) and non-infected (reverse) library were dipped onto the membrane for hybridization. A total of 112 differentially expressed sequence tags (ESTs) had been sequenced. For the host responses, 20% of ESTs (13 ESTs, 10 genes, and 1 non-coding RNA) from the forward library and 93.6% of ESTs (44 ESTs, 28 genes) from the reverse library were identified as differentially expressed genes (DEGs) of the hosts. A high percentage of DEGs involved in catalytic activity and metabolic processes revealed that the host gene expression change after N. ceranae infection might lead to an unbalance of physiological mechanism. Among the ESTs from the forward library, 75.4% ESTs (49 ESTs belonged to 24 genes) were identified as N. ceranae genes. Out of 24 N. ceranae genes, nine DEGs were subject to real-time quantitative reverse transcription PCR (real-time qRT-PCR) for validation. The results indicated that these genes were highly expressed during N. ceranae infection. Among nine N. ceranae genes, one N. ceranae gene (AAJ76_1600052943) showed the highest expression level after infection. These identified differentially expressed genes from this SSH could provide information about the pathological effects of N. ceranae. Validation of nine up-regulated N. ceranae genes reveal high potential for the detection of early nosemosis in the field and provide insight for further applications. Full article
Show Figures

Figure 1

Article
Larvicidal and Repellent Activity of Mentha arvensis L. Essential Oil against Aedes aegypti
Insects 2020, 11(3), 198; https://doi.org/10.3390/insects11030198 - 22 Mar 2020
Cited by 8 | Viewed by 1988
Abstract
Dengue is one of the most dangerous vector-borne diseases transmitted by Aedes mosquitoes. The use of mosquito repellents to protect human hosts and insecticides to reduce the mosquito population is a crucial strategy to prevent the disease. Here, we reported larvicidal and repellent [...] Read more.
Dengue is one of the most dangerous vector-borne diseases transmitted by Aedes mosquitoes. The use of mosquito repellents to protect human hosts and insecticides to reduce the mosquito population is a crucial strategy to prevent the disease. Here, we reported larvicidal and repellent activities of Mentha arvensis L. essential oil against Aedes aegypti, the main vector of the disease. The essential oil was extracted by hydro-distillation from the aromatic plant grown in Vietnam. The yield was 0.67% based on the weight of fresh leaves. The essential oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The main components were menthol (66.04%), menthyl acetate (22.19%), menthone (2.51%), and limonene (2.04%). Toxicity test on Aedes aegypti larvae showed that the median lethal concentrations, LC50 and LC90 were 78.1 ppm (part per million) and 125.7 ppm, respectively. Besides, the essential oil showed excellent repellency on Aedes aegypti mosquitoes. At 25%, 50%, and 100% concentration, the respective complete protection times (CPTs) were 45 min, 90 min, and 165 min. When adding 5% vanillin to the essential oil (25%), the complete protection time of the essential oil increased up to 120 min. In conclusion, the EO from Mentha arvensis L. has been shown to be a promising natural larvicide and repellent against Aedes aegypti mosquitoes. Full article
(This article belongs to the Special Issue Natural Substances against Insect Pests: Assets and Liabilities)
Show Figures

Figure 1

Article
Temperature Tolerance and Thermal Environment of European Seed Bugs
Insects 2020, 11(3), 197; https://doi.org/10.3390/insects11030197 - 20 Mar 2020
Cited by 3 | Viewed by 1140
Abstract
Heteroptera, or true bugs populate many climate zones, coping with different environmental conditions. The aim of this study was the evaluation of their thermal limits and derived traits, as well as climatological parameters which might influence their distribution. We assessed the thermal limits [...] Read more.
Heteroptera, or true bugs populate many climate zones, coping with different environmental conditions. The aim of this study was the evaluation of their thermal limits and derived traits, as well as climatological parameters which might influence their distribution. We assessed the thermal limits (critical thermal maxima, CTmax, and minima, CTmin) of eight seed bug species (Lygaeidae, Pyrrhocoridae) distributed over four Köppen–Geiger climate classification types (KCC), approximately 6° of latitude, and four European countries (Austria, Italy, Croatia, Bulgaria). In test tubes, a temperature ramp was driven down to −5 °C for CTmin and up to 50 °C for CTmax (0.25 °C/min) until the bugs’ voluntary, coordinated movement stopped. In contrast to CTmin, CTmax depended significantly on KCC, species, and body mass. CTmax showed high correlation with bioclimatic parameters such as annual mean temperature and mean maximum temperature of warmest month (BIO5), as well as three parameters representing temperature variability. CTmin correlated with mean annual temperature, mean minimum temperature of coldest month (BIO6), and two parameters representing variability. Although the derived trait cold tolerance (TC = BIO6 − CTmin) depended on several bioclimatic variables, heat tolerance (TH = CTmax − BIO5) showed no correlation. Seed bugs seem to have potential for further range shifts in the face of global warming. Full article
(This article belongs to the Special Issue Insects-Environment Interaction)
Show Figures

Figure 1

Communication
Selection of Predatory Mites for the Biological Control of Potato Tuber Moth in Stored Potatoes
Insects 2020, 11(3), 196; https://doi.org/10.3390/insects11030196 - 20 Mar 2020
Cited by 3 | Viewed by 1230
Abstract
Worldwide, the potato tuber moth (PTM), Phthorimaea operculella (Zeller), is one of the most severe pests affecting potato (Solanum tuberosum L.), whether in open-air crops or during tuber storage. This work examines the potential control of this pest by two species of [...] Read more.
Worldwide, the potato tuber moth (PTM), Phthorimaea operculella (Zeller), is one of the most severe pests affecting potato (Solanum tuberosum L.), whether in open-air crops or during tuber storage. This work examines the potential control of this pest by two species of predatory mites, Macrocheles robustulus (Berlese) and Blattisocius tarsalis (Berlese), on pest eggs under laboratory conditions. In the two first assays, the acceptance rate of the pest eggs was assessed for each predatory mite. Then, in a third assay, the functional response of B. tarsalis was studied. The results showed that Macrocheles robustulus did not prey on the pest eggs (number of eggs surviving = 4.33 ± 0.38), whereas B. tarsalis did (number of eggs surviving = 0.5 ± 0.5). Likewise, B. tarsalis showed a type II functional response when it killed the eggs. The results showed the potential use of Blattisocius tarsalis as a biological control agent of P. operculella in potato under storage conditions. Full article
Show Figures

Figure 1

Communication
Approaches to Identify the Value of Seminatural Habitats for Conservation Biological Control
Insects 2020, 11(3), 195; https://doi.org/10.3390/insects11030195 - 20 Mar 2020
Cited by 3 | Viewed by 1117
Abstract
Invertebrates perform many vital functions in agricultural production, but many taxa are in decline, including pest natural enemies. Action is needed to increase their abundance if more sustainable agricultural systems are to be achieved. Conservation biological control (CBC) is a key component of [...] Read more.
Invertebrates perform many vital functions in agricultural production, but many taxa are in decline, including pest natural enemies. Action is needed to increase their abundance if more sustainable agricultural systems are to be achieved. Conservation biological control (CBC) is a key component of integrated pest management yet has failed to be widely adopted in mainstream agriculture. Approaches to improving conservation biological control have been largely ad hoc. Two approaches are described to improve this process, one based upon pest natural enemy ecology and resource provision while the other focusses on the ecosystem service delivery using the QuESSA (Quantification of Ecological Services for Sustainable Agriculture) project as an example. In this project, a predictive scoring system was developed to show the potential of five seminatural habitat categories to provide biological control, from which predictive maps were generated for Europe. Actual biological control was measured in a series of case studies using sentinel systems (insect or seed prey), trade-offs between ecosystem services were explored, and heatmaps of biological control were generated. The overall conclusion from the QuESSA project was that results were context specific, indicating that more targeted approaches to CBC are needed. This may include designing new habitats or modifying existing habitats to support the types of natural enemies required for specific crops or pests. Full article
Show Figures

Figure 1

Article
Review of Eyeless Pseudosinella Schäffer (Collembola, Entomobryidae, and Lepidocyrtinae) from Brazilian Caves
Insects 2020, 11(3), 194; https://doi.org/10.3390/insects11030194 - 19 Mar 2020
Cited by 5 | Viewed by 1388
Abstract
Herein, eyeless Pseudosinella species from Brazilian caves are reviewed, including the description of 23 new species, new records plus additional notes on the descriptions of P. ambigua Zeppelini, Brito, and Lima and of P. guanhaensis Zeppelini, Brito, and Lima. We also provide an [...] Read more.
Herein, eyeless Pseudosinella species from Brazilian caves are reviewed, including the description of 23 new species, new records plus additional notes on the descriptions of P. ambigua Zeppelini, Brito, and Lima and of P. guanhaensis Zeppelini, Brito, and Lima. We also provide an identification key to 27 eyeless species recorded from Brazil. To organize the 26 Brazilian eyeless taxa analyzed in this work, we organize them in apparently artificial groups: 11 species have one larger tooth on the unguiculus outer lamella (petterseni group); one presents unguiculus outer lamella smooth or serrated (never with a larger tooth), with 9 held prelabral chaetae undivided and the last 6 held prelabral chaetae bifurcated. The Brazilian species of eyeless Pseudosinella herein described present a remarkably conservate dorsal chaetotaxy; therefore, the main diagnostic characters are related to other features like prelabral, labral, and ventral head chaetotaxy and empodial complex morphology. In addition, our study suggests that Brazilian caves possibly shelter a great diversity of Pseudosinella taxa, several of them potentially cave dependent. Full article
Show Figures

Figure 1

Article
Functional Characterization of Sex Pheromone Receptors in the Fall Armyworm (Spodoptera frugiperda)
Insects 2020, 11(3), 193; https://doi.org/10.3390/insects11030193 - 18 Mar 2020
Cited by 4 | Viewed by 1520
Abstract
Pheromone receptors (PRs) found in the antennae of male moths play a vital role in the recognition of sex pheromones released by females. The fall armyworm (FAW), Spodoptera frugiperda, is a notorious invasive pest, but its PRs have not been reported. In [...] Read more.
Pheromone receptors (PRs) found in the antennae of male moths play a vital role in the recognition of sex pheromones released by females. The fall armyworm (FAW), Spodoptera frugiperda, is a notorious invasive pest, but its PRs have not been reported. In this report, six candidate PRs (SfruOR6, 11, 13, 16, 56 and 62) suggested by phylogenetic analysis were cloned, and their tissue–sex expression profiles were determined by quantitative real-time PCR (qPCR). All six genes except for SfruOR6 were highly and specifically expressed in the antennae, with SfruOR6, 13 and 62 being male-specific, while the other three (SfruOR11, 16 and 56) were male biased, suggesting their roles in sex pheromone perception. A functional analysis by the Xenopus oocyte system further demonstrated that SfruOR13 was highly sensitive to the major sex pheromone component Z9-14:OAc and the pheromone analog Z9,E12-14:OAc, but less sensitive to the minor pheromone component Z9-12:OAc; SfruOR16 responded weakly to pheromone component Z9-14:OAc, but strongly to pheromone analog Z9-14:OH; the other four candidate PRs did not respond to any of the four pheromone components and four pheromone analogs. This study contributes to clarifying the pheromone perception in the FAW, and provides potential gene targets for developing OR-based pest control techniques. Full article
Show Figures

Graphical abstract

Article
Identification, Characterization and Expression Analysis of TRP Channel Genes in the Vegetable Pest, Pieris rapae
Insects 2020, 11(3), 192; https://doi.org/10.3390/insects11030192 - 18 Mar 2020
Cited by 1 | Viewed by 878
Abstract
Transient receptor potential (TRP) channels are critical for insects to detect environmental stimuli and regulate homeostasis. Moreover, this superfamily has become potential molecular targets for insecticides or repellents. Pieris rapae is one of the most common and widely spread pests of Brassicaceae plants. [...] Read more.
Transient receptor potential (TRP) channels are critical for insects to detect environmental stimuli and regulate homeostasis. Moreover, this superfamily has become potential molecular targets for insecticides or repellents. Pieris rapae is one of the most common and widely spread pests of Brassicaceae plants. Therefore, it is necessary to study TRP channels (TRPs) in P. rapae. In this study, we identified 14 TRPs in P. rapae, including two Water witch (Wtrw) genes. By contrast, only one Wtrw gene exists in Drosophila and functions in hygrosensation. We also found splice isoforms of Pyrexia (Pyx), TRPgamma (TRPγ) and TRP-Melastatin (TRPM). These three genes are related to temperature and gravity sensation, fine motor control, homeostasis regulation of Mg2+ and Zn2+ in Drosophila, respectively. Evolutionary analysis showed that the TRPs of P. rapae were well clustered into their own subfamilies. Real-time quantitative PCR (qPCR) showed that PrTRPs were widely distributed in the external sensory organs, including antennae, mouthparts, legs, wings and in the internal physiological organs, including brains, fat bodies, guts, Malpighian tubules, ovaries, as well as testis. Our study established a solid foundation for functional studies of TRP channels in P. rapae, and would be benefit to developing new approaches to control P. rapae targeting these important ion channels. Full article
Show Figures

Graphical abstract

Article
Equivocal Evidence for Colony Level Stress Effects on Bumble Bee Pollination Services
Insects 2020, 11(3), 191; https://doi.org/10.3390/insects11030191 - 18 Mar 2020
Cited by 5 | Viewed by 1709
Abstract
Climate change poses a threat to global food security with extreme heat events causing drought and direct damage to crop plants. However, by altering behavioural or physiological responses of insects, extreme heat events may also affect pollination services on which many crops are [...] Read more.
Climate change poses a threat to global food security with extreme heat events causing drought and direct damage to crop plants. However, by altering behavioural or physiological responses of insects, extreme heat events may also affect pollination services on which many crops are dependent. Such effects may potentially be exacerbated by other environmental stresses, such as exposure to widely used agro-chemicals. To determine whether environmental stressors interact to affect pollination services, we carried out field cage experiments on the buff-tailed bumble bee (Bombus terrestris). Using a Bayesian approach, we assessed whether heat stress (colonies maintained at an ambient temperature of 25 °C or 31 °C) and insecticide exposure (5 ng g-1 of the neonicotinoid insecticide clothianidin) could induce behavioural changes that affected pollination of faba bean (Vicia faba). Only the bumble bee colonies and not the plants were exposed to the environmental stress treatments. Bean plants exposed to heat-stressed bumble bee colonies (31 °C) had a lower proportional pod set compared to colonies maintained at 25 °C. There was also weak evidence that heat stressed colonies caused lower total bean weight. Bee exposure to clothianidin was found to have no clear effect on plant yields, either individually or as part of an interaction. We identified no effect of either colony stressor on bumble bee foraging behaviours. Our results suggest that extreme heat stress at the colony level may impact on pollination services. However, as the effect for other key yield parameters was weaker (e.g. bean yields), our results are not conclusive. Overall, our study highlights the need for further research on how environmental stress affects behavioural interactions in plant-pollinator systems that could impact on crop yields. Full article
(This article belongs to the Special Issue The Impacts of Pesticides on Pollinators)
Show Figures

Figure 1

Article
Agri-Food Side-Stream Inclusion in The Diet of Alphitobius Diaperinus. Part 2: Impact on Larvae Composition
Insects 2020, 11(3), 190; https://doi.org/10.3390/insects11030190 - 17 Mar 2020
Cited by 3 | Viewed by 917
Abstract
Insects are gaining interest as an alternative protein source for feed/food purposes. Although the lesser mealworm (LM) is commercially produced for human consumption, published data on its nutrient composition is scarce. This study reports on LM larvae reared on 18 different diets composed [...] Read more.
Insects are gaining interest as an alternative protein source for feed/food purposes. Although the lesser mealworm (LM) is commercially produced for human consumption, published data on its nutrient composition is scarce. This study reports on LM larvae reared on 18 different diets composed of side-streams to (1) determine the nutritional composition of the larvae and (2) study the effect of dietary changes on the larval nutrient composition. The LM larvae proved to be of good nutritional value with essential amino acids profiles comparable with that of beef and linoleic acid (C18:2) was the most dominant essential fatty acids in the larvae. The side-stream based diets varied on dry matter basis in protein (16–34%) and lipid content (2–19%). The nutrient content of the larvae reared on diets that supported good growth ranged between 37% and 49% of protein, 22% and 26% of lipid and 4% to 6% of chitin on dry matter basis. No significant correlations were identified between the larval protein or lipid content and that of the diet, but it was found between the diet nutrients and larval growth. Based on larval growth data and economic considerations, diets composed of wheat middlings with a 10–15% inclusion of rapeseed meal were identified as suitable feed for LM. Highest larval yields were obtained with diets containing 15–22% of proteins and 5–10% of lipids. Full article
Show Figures

Figure 1

Article
Role of Fruit Epicuticular Waxes in Preventing Bactrocera oleae (Diptera: Tephritidae) Attachment in Different Cultivars of Olea europaea
Insects 2020, 11(3), 189; https://doi.org/10.3390/insects11030189 - 17 Mar 2020
Cited by 8 | Viewed by 931
Abstract
The olive fruit fly Bactrocera oleae (Diptera: Tephritidae) is the major pest of cultivated olives (Olea europaea L.), and a serious threat in all of the Mediterranean Region. In the present investigation, we demonstrated with traction force experiments that B. oleae female [...] Read more.
The olive fruit fly Bactrocera oleae (Diptera: Tephritidae) is the major pest of cultivated olives (Olea europaea L.), and a serious threat in all of the Mediterranean Region. In the present investigation, we demonstrated with traction force experiments that B. oleae female adhesion is reduced by epicuticular waxes (EWs) fruit surface, and that the olive fruit fly shows a different ability to attach to the ripe olive surface of different cultivars of O. europaea (Arbequina, Carolea, Dolce Agogia, Frantoio, Kalamata, Leccino, Manzanilla, Picholine, Nostrale di Rigali, Pendolino and San Felice) in terms of friction force and adhesion, in relation with different mean values of olive surface wettability. Cryo-scanning morphological investigation revealed that the EW present on the olive surface of the different analyzed cultivars are represented by irregular platelets varying in the orientation, thus contributing to affect the surface microroughness and wettability in the different cultivars, and consequently the olive fruit fly attachment. Further investigations to elucidate the role of EW in olive varietal resistance to the olive fruit fly in relation to the olive developmental stage and environmental conditions could be relevant to develop control methods alternative to the use of harmful pesticides. Full article
(This article belongs to the Special Issue Physical and Chemical Interactions between Insects and Plants)
Show Figures

Figure 1

Article
Two Roles for the Tenebrio molitor Relish in the Regulation of Antimicrobial Peptides and Autophagy-Related Genes in Response to Listeria monocytogenes
Insects 2020, 11(3), 188; https://doi.org/10.3390/insects11030188 - 16 Mar 2020
Cited by 6 | Viewed by 1335
Abstract
Relish is a key NF-κB transcription factor of the immune-deficiency (Imd) pathway that combats infection by regulating antimicrobial peptides (AMPs). Understanding of the fundamental role of Tenebrio molitor Relish (TmRelish) in controlling of Listeria monocytogenes virulence through the regulation of both [...] Read more.
Relish is a key NF-κB transcription factor of the immune-deficiency (Imd) pathway that combats infection by regulating antimicrobial peptides (AMPs). Understanding of the fundamental role of Tenebrio molitor Relish (TmRelish) in controlling of Listeria monocytogenes virulence through the regulation of both AMPs and autophagy-related (ATG) genes is unclear. Here, we show that TmRelish transcripts were highly abundant in the larval fat body and hemocytes compared to the gut upon L. monocytogenes infection. Furthermore, significant mortality was observed in TmRelish-silenced larvae after intracellular insult. To investigate the cause of this lethality, we measured the induction of AMPs and ATG genes in the TmRelish dsRNA-treated T. molitor larvae. The expression of TmTenecin-1, TmTenecin-4, TmColeptericin-1, TmAttacin-2, and TmCecropin-2 were suppressed in the fat body and hemocytes of dsTmRelish-injected larvae during L. monocytogenes infection. In addition, TmRelish knockdown led to a noticeable downregulation of TmATG1 (a serine-threonine protein kinase) in the fat body and hemocytes of young larvae 6 h post-infection (pi). The notable increase of autophagy genes in the early stage of infection (6 h pi), suggesting autophagy response is crucial for Listeria clearance. Taken together, these results suggest that TmRelish plays pivotal roles in not only regulation of AMP genes but also induction of autophagy genes in response to L. monocytogenes challenge in fat body and hemocytes of T. molitor larvae. Furthermore, negative regulation of several AMPs by TmRelish in the fat body, hemocytes, and gut leaves open the possibility of a crosstalk between Toll and Imd pathway. Full article
Show Figures

Figure 1

Article
Analysis of Pole-Ascending–Descending Action by Insects Subjected to High Voltage Electric Fields
Insects 2020, 11(3), 187; https://doi.org/10.3390/insects11030187 - 16 Mar 2020
Cited by 5 | Viewed by 985
Abstract
The present study was conducted to establish an electrostatic-based experimental system to enable new investigations of insect behavior. The instrument consists of an insulated conducting copper ring (ICR) linked to a direct current voltage generator to supply a negative charge to an ICR [...] Read more.
The present study was conducted to establish an electrostatic-based experimental system to enable new investigations of insect behavior. The instrument consists of an insulated conducting copper ring (ICR) linked to a direct current voltage generator to supply a negative charge to an ICR and a grounded aluminum pole (AP) passed vertically through the center of the horizontal ICR. An electric field was formed between the ICR and the AP. Rice weevil (Sitophilus oryzae) was selected as a model insect due to its habit of climbing erect poles. The electric field produced a force that could be imposed on the insect. In fact, the negative electricity (free electrons) was forced out of the insect to polarize its body positively. Eventually, the insect was attracted to the oppositely charged ICR. The force became weaker on the lower regions of the pole; the insects sensed the weaker force with their antennae, quickly stopped climbing, and retraced their steps. These behaviors led to a pole-ascending–descending action by the insect, which was highly reproducible and precisely corresponded to the changed expansion of the electric field. Other pole-climbing insects including the cigarette beetle (Lasioderma serricorne), which was shown to adopt the same behavior. Full article
Show Figures

Figure 1

Article
Gene Expression Profiling Indicated Diverse Functions and Characteristics of Core Genes in Pea Aphid
Insects 2020, 11(3), 186; https://doi.org/10.3390/insects11030186 - 15 Mar 2020
Cited by 1 | Viewed by 859
Abstract
The pea aphid is a global insect pest, and variable phenotypes can be produced by pea aphids in the same genotype in response to changes in external environmental factors. However, detailed dynamic gene regulation networks and the core markers involved in different biological [...] Read more.
The pea aphid is a global insect pest, and variable phenotypes can be produced by pea aphids in the same genotype in response to changes in external environmental factors. However, detailed dynamic gene regulation networks and the core markers involved in different biological processes of pea aphids have not yet been reported. In this study, we obtained the published genomic and transcriptomic data, and performed transcriptome profiling of five pea aphid morphs (winged asexual female, wingless asexual female, wingless sexual female, winged male and wingless male) from each of three pea aphid genotypes, i.e., the transcriptomes from a total of 15 types of pea aphids were analyzed and the type-specific expression of genes in five different morphs was identified. The expression profiling was verified by quantitative real-time PCR (qPCR) analysis. Moreover, we determined the expression features and co-expression networks of highly variable genes. We also used the ARACNe method to obtain 263 core genes related to different biological pathways. Additionally, eight of the identified genes were aligned with transcription factor families, indicating that they act as transcription factors and regulate downstream genes. Furthermore, we found reliable markers using random forest methodology to distinguish different morphs of pea aphids. Our study provides a systematic and comprehensive approach for analyzing the core genes that may play important roles in a multitude of biological processes from the insect transcriptomes. Full article
Show Figures

Figure 1

Article
Landscape Effects on the Abundance of Apolygus lucorum in Cotton Fields
Insects 2020, 11(3), 185; https://doi.org/10.3390/insects11030185 - 14 Mar 2020
Viewed by 766
Abstract
Resource-continuity over spatial and temporal scales plays a central role in the population abundance of polyphagous pests in an agricultural landscape. Shifts in the agricultural land use in a region may alter the configuration of key resource habitats, resulting in drastic changes in [...] Read more.
Resource-continuity over spatial and temporal scales plays a central role in the population abundance of polyphagous pests in an agricultural landscape. Shifts in the agricultural land use in a region may alter the configuration of key resource habitats, resulting in drastic changes in pest abundance. Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is a pest of cotton in northern China that has become more serious in recent years following changes in the region’s cropping systems. However, no evidence from the landscape perspective has yet been gathered to account for the increasing population of A. lucorum in China. In this study, we investigated the effects of landscape composition on the population abundance of A. lucorum in cotton fields in July and August of 2016, respectively. We found that increased acreage planted to cotton actually had a negative effect on the abundance of A. lucorum, while planting of other crops (e.g., vegetables, soybean, and peanut) was positively associated with the mirid’s population abundance in cotton fields. Maize production only displayed a positive effect on population abundance in August. Our results suggested that the decreasing of cotton area may weaken the trap-kill effect on A. lucorum, and the extension of other crops and maize potentially enhance the continuity of resources needed by A. lucorum. Combined effects of these two aspects may promote an increased population density of A. lucorum in the agriculture district. In the future, when possible, management strategies in key regional crops should be coordinated to reduce resource continuity at the landscape or area-wide scale to lower A. lucorum populations across multiple crops. Full article
Show Figures

Figure 1

Article
Effects of Topical Tebufenozide Application to Choristoneura fumiferana Pupae (Lepidoptera: Tortricidae)
Insects 2020, 11(3), 184; https://doi.org/10.3390/insects11030184 - 14 Mar 2020
Viewed by 710
Abstract
Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) is a defoliating pest in Canada and the northeastern United States. Given its important ecological and economic effects in affected regions, several direct management techniques have been developed, including the application of the insect growth regulator tebufenozide (Mimic™, [...] Read more.
Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) is a defoliating pest in Canada and the northeastern United States. Given its important ecological and economic effects in affected regions, several direct management techniques have been developed, including the application of the insect growth regulator tebufenozide (Mimic™, RH-5992) to feeding larval stages. While the effectiveness of tebufenozide, in this capacity, is understood, management programs of other lepidopteran pests have demonstrated the effectiveness of tebufenozide application when utilized against other life stages. Here, we investigated the toxicity of topically-applied tebufenozide to C. fumiferana pupae to determine if such a strategy could be feasible. We observed significant dose-dependent decreases in the likelihood of adult emergence, increases in the likelihood of pupal death or adult deformity at eclosion, and significant decreases in mean adult longevity. Estimated LD 50 (lethal dose) values for adult male and female C. fumiferana treated as pupae ≤ 4 days after pupation were approximately 1–3 and 2–3.5% ACI (active commercial ingredient) respectively. Estimated L-SD (lethal-sublethal) 50 doses for adult male and female C. fumiferana treated as pupae ≤4 days after pupation were <1, and <2% ACI, respectively. Mating success was also significantly lower in mating pairs containing adults treated as pupae. Although, the amounts required to cause appreciable pupal mortality were much higher than those currently applied operationally in the C. fumiferana system, our study illustrates the potential of tebufenozide to utilized against additional developmental stages in other lepidopteran pests. Full article
Show Figures

Figure 1

Review
The Chironomidae (Diptera) of Svalbard and Jan Mayen
Insects 2020, 11(3), 183; https://doi.org/10.3390/insects11030183 - 13 Mar 2020
Viewed by 2218
Abstract
Non-biting midges of the fly family Chironomidae are extremely abundant and diverse in Arctic regions and are essential components of Arctic ecosystems. Modern identification tools based on documented records of Arctic chironomid species are therefore important for ecological research and environmental monitoring in [...] Read more.
Non-biting midges of the fly family Chironomidae are extremely abundant and diverse in Arctic regions and are essential components of Arctic ecosystems. Modern identification tools based on documented records of Arctic chironomid species are therefore important for ecological research and environmental monitoring in the region. Here, we provide an updated review of the chironomid fauna of the Svalbard archipelago and the island of Jan Mayen, Norway. Our results show that a total of 73 species distributed across 24 genera in four subfamilies are known from these areas. Our review treats 109 taxa, including nomina dubia and misidentifications. It includes morphological identification keys to all known species as well as photographs of most taxa and DNA barcodes of 66 species. Taxonomic remarks are given for selected taxa, including previous misidentifications and erroneous records. Chironomus islandicus, Tvetenia bavarica, Limnophyes schnelli, Metriocnemus brusti and Metriocnemus fuscipes as well as the genera Allocladius, Corynoneura and Bryophaenocladius are reported from Svalbard for the first time, while Procladius (Holotanypus) frigidus, Stictochironomus psilopterus, Chaetocladius incertus, Orthocladius (Orthocladius) mixtus and Smittia longicosta, previously considered as junior synonyms or nomina dubia, are revived as valid species based on examination of type material or literature. Twenty species within eleven genera are introduced with interim names. Metriocnemus similis is regarded as a junior synonym of Metriocnemus ursinus, and Smittia incerta, Smittia flexinervis and Smittia spitzbergensis are regarded as nomina dubia. Valid taxa no longer considered as part of the Svalbard fauna are Parochlus kiefferi, Arctopelopia barbitarsis, Procladius (Holotanypus) crassinervis, Diamesa lindrothi, Diamesa incallida, Diamesa lundstromi, Chironomus hyperboreus, Sergentia coracina, Camptocladius stercorarius, Chaetocladius dissipatus, Chaetocladius dentiforceps, Chaetocladius laminatus, Chaetocladius perennis, Cricotopus (Cricotopus) humeralis, Cricotopus (Cricotopus) polaris, Hydrosmittia ruttneri, Limnophyes edwardsi, Metriocnemus picipes, Metriocnemus tristellus, Orthocladius (Eudactylocladius) gelidus, Orthocladius (Euorthocladius) thienemanni, Orthocladius (Orthocladius) obumbratus, Orthocladius (Orthocladius) rhyacobius, Paralimnophyes, Paraphaenocladius impensus, Psectrocladius (Monopsectrocladius) calcaratus, Psectrocladius (Psectrocladius) psilopterus, Psectrocladius (Psectrocladius) ventricosus, Smittia lasiophthalma, Smittia lasiops and Zalutschia tatrica. Full article
(This article belongs to the Special Issue Polar Entomology)
Show Figures

Figure 1

Article
Effects of Diaphorina citri Population Density on Daily Timing of Vibrational Communication Calls: Potential Benefits in Finding Forage
Insects 2020, 11(3), 182; https://doi.org/10.3390/insects11030182 - 13 Mar 2020
Viewed by 706
Abstract
Adult Diaphorina citri (ACP) use visual and chemical cues to locate young citrus flush shoots on which they forage and oviposit, and they use vibrational communication duetting calls as cues to help locate mates. For individual pairs, calling and mating usually peaks between [...] Read more.
Adult Diaphorina citri (ACP) use visual and chemical cues to locate young citrus flush shoots on which they forage and oviposit, and they use vibrational communication duetting calls as cues to help locate mates. For individual pairs, calling and mating usually peaks between 10:00 and 15:00. To explore whether call rates (calls/h) are affected by interactions with nearby conspecifics, rates were compared in small citrus trees on which either 5 or 25 ACP female and male pairs had been released at 17:00 for later recording from sunrise (06:00) to 22:00. Final ACP locations were noted 40 h after release. Call rates were similar in both treatments during normal mating hours. However, rates were significantly higher for low- than high-density treatments between 06:00 and 10:00, which suggests calling during this period may be affected by conspecific density. Both sexes aggregated on flush at both densities. We discuss the potential that ACP producing calls near sunrise, outside of normal mating hours, might benefit from gains in reproductive fitness in low-density contexts if they call not only to locate mates but also to locate preferred flush—in which case, co-opting of vibrations to disrupt both mating and foraging may be feasible. Full article
Show Figures

Figure 1

Article
Age-Stage, Two-Sex Life Tables of the Predatory Mite Cheyletus Malaccensis Oudemans at Different Temperatures
Insects 2020, 11(3), 181; https://doi.org/10.3390/insects11030181 - 12 Mar 2020
Viewed by 1765
Abstract
Cheyletus malaccensis Oudemans is a predatory mite inhabiting grain depots in China. The relationship between temperature and the population growth rate of C. malaccensis is useful for predicting its population dynamics. Age-stage, two-sex life tables of the predator, C. malaccensis, reared on [...] Read more.
Cheyletus malaccensis Oudemans is a predatory mite inhabiting grain depots in China. The relationship between temperature and the population growth rate of C. malaccensis is useful for predicting its population dynamics. Age-stage, two-sex life tables of the predator, C. malaccensis, reared on Acarus siro were constructed under laboratory conditions at 22, 24, 28, 30, and 32 °C, 75% relative humidity, and a 0:24 h (L:D) photoperiod. Increasing temperature shortened the development time of the immature stages. The complete generation time of C. malaccensis ranged from 11.10 d to 27.50 d. Life table parameters showed that 28 °C was the optimum temperature for the growth and development of C. malaccensis; populations could increase rapidly at this temperature. The highest net reproductive rate (R0 = 290.25) and highest fecundity (544.52) occurred at 28 °C. Temperature significantly affected the intrinsic rate of increase (r), fecundity, and finite rate of increase (λ). The values of age-specific fecundity (high to low) were 28 °C > 24 °C > 30 °C > 32 °C > 22 °C, while the values of age-stage-specific fecundity had the same trend. Full article
(This article belongs to the Special Issue Biological Control and Insect Pathology)
Show Figures

Figure 1

Article
Insecticidal and Cholinesterase Activity of Dichloromethane Extracts of Tithonia diversifolia on Atta cephalotes Worker Ants (Formicidae: Myrmicinae)
Insects 2020, 11(3), 180; https://doi.org/10.3390/insects11030180 - 11 Mar 2020
Cited by 2 | Viewed by 916
Abstract
Leaf-cutter ants are agricultural and urban pests that defy chemical control methods. Laboratory and field studies have revealed repellent and insecticidal activity by the extracts of Tithonia diversifolia (Asteraceae), known as Mexican sunflower, as a promising alternative for the control of the leaf-cutter [...] Read more.
Leaf-cutter ants are agricultural and urban pests that defy chemical control methods. Laboratory and field studies have revealed repellent and insecticidal activity by the extracts of Tithonia diversifolia (Asteraceae), known as Mexican sunflower, as a promising alternative for the control of the leaf-cutter ant Atta cephalotes. This study evaluated the effects of different extracts (non-polar and polar) of T. diversifolia dry leaves on worker ants from laboratory colonies of A. cephalotes through ingestion and contact. In addition, the biological activity of the extracts as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was evaluated. A dichloromethane extract at 1000 ppm presented the highest insecticidal activity through ingestion, causing 70% and 90% worker ant mortality after five and seven days of treatment, respectively. The acetylcholinesterase inhibition values showed that the dichloromethane presented the best AChE concentration of inhibition (IC50) at 73.9 ± 11.06 μg/mL, compared to its fractions, which demonstrates that its activity is potentiated when the crude extract is used. Our results can be attributed to the existence of terpenes and sesquiterpene lactones, which are likely inhibitors of AChE, in T. diversifolia. Full article
Show Figures

Graphical abstract

Article
Bacterial Endosymbiont Diversity among Bemisia tabaci (Hemiptera: Aleyrodidae) Populations in Florida
Insects 2020, 11(3), 179; https://doi.org/10.3390/insects11030179 - 11 Mar 2020
Cited by 3 | Viewed by 846
Abstract
The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a pest of many economically important agricultural crops and a vector of plant viruses. Bemisia tabaci harbors facultative endosymbiont species that have been implicated in pest status, including tolerance to insecticides, virus transmission efficiency and [...] Read more.
The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), is a pest of many economically important agricultural crops and a vector of plant viruses. Bemisia tabaci harbors facultative endosymbiont species that have been implicated in pest status, including tolerance to insecticides, virus transmission efficiency and tolerance to high-temperatures. The facultative endosymbionts reported in B. tabaci include Arsenophonus, Hamiltonella, Wolbachia, Cardinium, Fritschea and Rickettsia. We collected whitefly populations from weed and crop hosts in south Florida and identified the whitefly species as well as the facultative endosymbionts present in these populations by molecular analysis. In addition, a phylogenetic analysis of whiteflies and their endosymbionts was performed. The only facultative endosymbionts found among the B. tabaci populations collected in Florida were Hamiltonella and Rickettsia. The phylogenetic analysis revealed the low genetic diversity of whiteflies and their endosymbionts. Additionally, the phylogenetic tree clustered Rickettsia from Florida in the R1 genetic group. The results will aid to understand the role of the bacterial endosymbionts in the whitefly host. Full article
Show Figures

Figure 1

Article
Assessment of Lethal, Sublethal, and Transgenerational Effects of Beauveria bassiana on the Demography of Aedes albopictus (Culicidae: Diptera)
Insects 2020, 11(3), 178; https://doi.org/10.3390/insects11030178 - 11 Mar 2020
Cited by 4 | Viewed by 1085
Abstract
Dengue fever is one of the most rapidly spreading arthropod-borne diseases. Diurnal vectorial properties of Aedes albopictus contribute to the dispersion of the dengue viruses. Frequent and injudicious use of synthetic insecticides led to the evolution of resistant phenotypes in Ae. albopictus which [...] Read more.
Dengue fever is one of the most rapidly spreading arthropod-borne diseases. Diurnal vectorial properties of Aedes albopictus contribute to the dispersion of the dengue viruses. Frequent and injudicious use of synthetic insecticides led to the evolution of resistant phenotypes in Ae. albopictus which necessitates the search for an alternative of current control strategies. Developing a long-lasting and environmentally safe tactic based on knowledge of ecology and population dynamics of Ae. albopictus is critical. Therefore, with a view towards biological control and ecology, the effect of entomopathogenic fungi (EPF) Beauveria bassiana on filial and first filial generations of Ae. albopictus were studied. Investigations showed 87.5% adulticidal activity leading to altered fecundity and adult longevity in a filial generation. The lethal (LC50) and sublethal (LC20) concentrations of B. bassiana were applied to filial generation (F0) to study demographic parameters in the first filial generation (F1). Results showed reduced net reproductive rates (Ro) intrinsic rate of increase (r), and mean generation time (T) compared to uninfected controls. Prolonged larval and pupal duration were observed followed by reduced longevity of male and female adults. Fecundity in the first filial generation was significantly changed with the lethal and sublethal concentrations of B. bassiana. Thus, it is concluded that B. bassiana has the potential to play a vital role in integrated mosquito management strategies. Full article
(This article belongs to the Special Issue Control of Mosquitoes, Biting Midges, Horse Flies and Deer Flies)
Show Figures

Figure 1

Article
Behavioral Responses of Western Flower Thrips (Frankliniella occidentalis) to Visual and Olfactory Cues at Short Distances
Insects 2020, 11(3), 177; https://doi.org/10.3390/insects11030177 - 11 Mar 2020
Cited by 7 | Viewed by 998
Abstract
Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is a highly invasive pest, infesting many species of plants worldwide, but few studies have investigated the visual and olfactory cues associated with their foraging behaviors. In this study, the distance traveled by WFT to locate [...] Read more.
Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is a highly invasive pest, infesting many species of plants worldwide, but few studies have investigated the visual and olfactory cues associated with their foraging behaviors. In this study, the distance traveled by WFT to locate yellow cards using only visual cues and visual cues plus olfactory cues was studied first. Subsequently, preferences for colors (white, red, green, purple, yellow and blue) and patterns (triangle, rectangle, circle and flower-shape) over short distances were assessed with free-choice tests. Finally, as yellow was the most efficient color to catch WFT under laboratory conditions, the yellow flower-shape was used as the visual cue, and preferences between visual and olfactory cues were evaluated with dual choice tests. The results showed that the capture rate of WFT by visual cues decreased as selection distance increased, however capture rate remained higher with the addition of olfactory cues. The flower shape attracted the greatest number of WFT among all shapes tested. The combination of visual cues and extracted volatiles from flowering Medicago sativa L. attracted higher numbers of WFT than to the olfactory cues alone, however these were similar to visual cues alone. The presence of olfactory cues resulted in higher residence times by WFT than did the absence of olfactory cues. These results show the relative effects of visual and olfactory cues on the orientation of WFT to hosts and highlight that visual cues dominate selection behavior at short distances. These findings can be used in the development of efficient trapping products and management strategies for thrips. Full article
Show Figures

Figure 1

Article
Transcriptomic Analysis Following Artificial Selection for Grasshopper Size
Insects 2020, 11(3), 176; https://doi.org/10.3390/insects11030176 - 10 Mar 2020
Viewed by 1103
Abstract
We analyzed the transcriptomes of Romalea microptera grasshoppers after 8 years of artificial selection for either long or short thoraces. Evolution proceeded rapidly during the experiment, with a 13.3% increase and a 32.2% decrease in mean pronotum lengths (sexes combined) in the up- [...] Read more.
We analyzed the transcriptomes of Romalea microptera grasshoppers after 8 years of artificial selection for either long or short thoraces. Evolution proceeded rapidly during the experiment, with a 13.3% increase and a 32.2% decrease in mean pronotum lengths (sexes combined) in the up- and down-selected colonies, respectively, after only 11 generations. At least 16 additional traits also diverged between the two colonies during the selection experiment. Transcriptomic analysis identified 693 differentially expressed genes, with 386 upregulated and 307 downregulated (55.7% vs. 44.3%), including cellular process, metabolic process, binding, general function prediction only, and signal transduction mechanisms. Many of the differentially expressed genes (DEGs) are known to influence animal body size. Full article
Show Figures

Graphical abstract

Article
Host Specificity of the Parasitic Wasp Anaphes flavipes (Hymenoptera: Mymaridae) and a New Defence in Its Hosts (Coleoptera: Chrysomelidae: Oulema spp.)
Insects 2020, 11(3), 175; https://doi.org/10.3390/insects11030175 - 10 Mar 2020
Cited by 1 | Viewed by 1396
Abstract
The parasitic wasp Anaphes flavipes (Förster, 1841) (Hymenoptera: Mymaridae) is an important egg parasitoid of cereal leaf beetles. Some species of cereal leaf beetle co-occur in the same localities, but the host specificity of the wasp to these crop pests has not yet [...] Read more.
The parasitic wasp Anaphes flavipes (Förster, 1841) (Hymenoptera: Mymaridae) is an important egg parasitoid of cereal leaf beetles. Some species of cereal leaf beetle co-occur in the same localities, but the host specificity of the wasp to these crop pests has not yet been examined in detail. A lack of knowledge of host specificity can have a negative effect on the use of this wasps in biological control programs addressed to specific pest species or genus. In this study, laboratory experiments were conducted to assess the host specificity of A. flavipes for three species of cereal leaf beetles (Oulema duftschmidi Redtenbacher, 1874, Oulema gallaeciana Heyden, 1879 and Oulema melanopus Linnaeus, 1758) in central Europe. For the first time, a new host defence against egg parasitoids occurring in O. gallaeciana from localities in the Czech Republic, a strong dark sticky layer on the egg surface, was found and described. The host specificity of A. flavipes was studied in the locality with the presence of this defence on O. gallaeciana eggs (the dark sticky layer) (Czech Republic) and in a control locality (Germany), where no such host defence was observed. Contrary to the idea that a host defence mechanism can change the host specificity of parasitoids, the wasps from these two localities did not display any differences in that. Respectively, even though it has been observed that eggs with sticky dark layer can prevent parasitization, the overall rate of parasitization of the three species of cereal beetles has not been affected. However, in our view, new host defence can influence the effects of biological control, as eggs of all Oulema spp. in the locality are protected against parasitization from the wasps stuck on the sticky layer of the host eggs of O. gallaeciana. Full article
Show Figures

Figure 1

Article
The Oldest Representative of the Rove Beetle Tribe Pinophilini (Coleoptera: Staphylinidae: Paederinae), from Upper Cretaceous Burmese Amber
Insects 2020, 11(3), 174; https://doi.org/10.3390/insects11030174 - 10 Mar 2020
Viewed by 1740
Abstract
The recently reviewed subtribe Procirrina comprises eight extant genera with a predominately (sub)tropical distribution. Previous phylogenies consistently recover the tribe Pinophilini of the subfamily Paederinae monophyletic. No fossils of the tribe have been described, although compression fossils are known from the Cenozoic Green [...] Read more.
The recently reviewed subtribe Procirrina comprises eight extant genera with a predominately (sub)tropical distribution. Previous phylogenies consistently recover the tribe Pinophilini of the subfamily Paederinae monophyletic. No fossils of the tribe have been described, although compression fossils are known from the Cenozoic Green River Formation (50.3–46.2 Ma) as well as inclusions from the Miocene Dominican (20.43–13.65 Ma) and Mexican (20–15 Ma) ambers. Here we describe †Cretoprocirrus trichotos Jenkins Shaw and Żyła gen. et sp. n., the oldest fossil representative of the tribe Pinophilini, from Upper Cretaceous Burmese amber (ca. 99 Ma). Phylogenetic analyses of morphological data allow its unambiguous placement in the subtribe Procirrina. †Cretoprocirrus trichotos is the second genus of Paederinae described from Burmese amber and provides an important insight into the evolution of the subfamily. Full article
Show Figures

Graphical abstract

Article
Protura in Arctic Regions, with Description of Mastodonentomon n. gen. (Acerentomidae, Nipponentominae) and a Key to Known Arctic Taxa
Insects 2020, 11(3), 173; https://doi.org/10.3390/insects11030173 - 09 Mar 2020
Cited by 1 | Viewed by 778
Abstract
Protura are widespread, but their presence in the Arctic was first noted only ca. 70 years ago and is still little acknowledged. This work compiles taxonomic information on proturans in the Arctic regions and adds unpublished data from Northern Siberia. Currently, this fauna [...] Read more.
Protura are widespread, but their presence in the Arctic was first noted only ca. 70 years ago and is still little acknowledged. This work compiles taxonomic information on proturans in the Arctic regions and adds unpublished data from Northern Siberia. Currently, this fauna is represented by 23 species in two orders and 14 genera. The large cosmopolitan genus Eosentomon is represented by only four species, whereas Acerentomidae is much more diverse, with 19 species in 13 genera (eight Nipponentominae, five Acerentominae). Most of the Arctic species possess a larger number of setae than species living in temperate regions. Based on several unique characters, a new genus, Mastodonentomon, is erected for Nipponentomon macleani, and the species is re-described with the original description supplemented with new characters, including head chaetotaxy, seta length, and porotaxy. Proturan occurrence in the Arctic is limited to Beringia, but the majority of species have restricted distributions and none have been found in both the American Arctic and Siberia. This implies relict origins and high levels of proturan endemism in the Arctic. This emerging view on biogeographical history is, however, hampered by the limited extent of available data, which highlights the need for considerably greater survey efforts. A key to Arctic proturans is provided to facilitate further studies. Full article
(This article belongs to the Special Issue Polar Entomology)
Show Figures

Figure 1

Previous Issue
Next Issue
Back to TopTop