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Insects, Volume 10, Issue 8 (August 2019)

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Cover Story (view full-size image) Diseases transmitted by ticks are a growing concern worldwide, including in the Northeastern US, [...] Read more.
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Open AccessArticle
Influence of Age, Host Plant and Mating Status in Pheromone Production and New Insights on Perception Plasticity in Tuta Absoluta
Insects 2019, 10(8), 256; https://doi.org/10.3390/insects10080256 - 20 Aug 2019
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Abstract
The tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato worldwide. However, in spite of its tremendous economic importance, the success of environmentally friendly measures to control the pest is still limited. Study of physiological and [...] Read more.
The tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato worldwide. However, in spite of its tremendous economic importance, the success of environmentally friendly measures to control the pest is still limited. Study of physiological and behavioral parameters that affect pheromone production has provided useful information for pest management. Our results show no clear difference in pheromone production by females over the period from 2 h before to 2 h after the scotophase. However, pheromone production was clearly dependent on female age, with young females producing the highest amount of each pheromone component 10 days after emergence. In the presence of the host plant (physical contact and olfaction of the plant volatiles), virgin and mated females produced higher amounts of the major component of the pheromone (TDTA) than those in the absence of plant and those devoid of olfaction (antennectomized) but in physical contact with the plant. In electrophysiological experiments, TDTA elicited slightly lower responses on male antennae than the pheromone mixture. When stimulated at certain time intervals after the first exposure to TDTA, male antennae became more sensitive to the stimulus (sensitization effect). For the first time in an insect of the family Gelechiidae, we have found that females are able to detect their own pheromone (autodetection). Altogether, our results may represent a step forward in the knowledge of the chemical communication of this important pest. Full article
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Open AccessArticle
Seasonal Dynamics of the Leaffooted Bug Leptoglossus zonatus and Its Implications for Control in Almonds and Pistachios
Insects 2019, 10(8), 255; https://doi.org/10.3390/insects10080255 - 19 Aug 2019
Viewed by 359
Abstract
Leptoglossus zonatus is a polyphagous pest found throughout much of the Western Hemisphere. In California, L. zonatus attacks almond, pistachio, pomegranate, and walnut crops, but the seasonal use of and economic damage to these crops varies. To better understand the seasonal changes of [...] Read more.
Leptoglossus zonatus is a polyphagous pest found throughout much of the Western Hemisphere. In California, L. zonatus attacks almond, pistachio, pomegranate, and walnut crops, but the seasonal use of and economic damage to these crops varies. To better understand the seasonal changes of L. zonatus populations and to improve monitoring programs in California’s San Joaquin Valley, we caged overwintering adult males and females and then followed the resulting population dynamics over a one-year period. There were three generations over the one-year period, although eggs, nymphs, and adults overlapped among successive generations. From an initial 75 overwintering adult females, there were 1214 egg strands, 16,692 nymphs, and 4900 adults recorded during the one-year period. Depending on the generation, the number of nymphs per egg strand ranged from 11.3 to 14.3; the sex ratio was close to 1:1 with the exception of one female-biased cage; and nymph mortality ranged from 22.0% to 39.5%. Adult females isolated from each generation produced 2.4–5.1 egg strands per female that totaled 41.7–61.7 eggs per female with a 67.1–86.8% successful hatch rate. We find that the adult is the overwintering stage, as more adults (without food provisions) survived the winter compared to medium-sized or large-sized nymphs provided with both food and water. The results are discussed with respect to the development of L. zonatus control and monitoring programs for California’s multi-billion-dollar (US) nut crops. Full article
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Open AccessArticle
CRISPR Disruption of BmOvo Resulted in the Failure of Emergence and Affected the Wing and Gonad Development in the Silkworm Bombyx mori
Insects 2019, 10(8), 254; https://doi.org/10.3390/insects10080254 - 19 Aug 2019
Viewed by 488
Abstract
The domesticated silkworm is an economically important insect that is widely used as a lepidopteran insect model. Although somatic sex determination in the silkworm is well characterized, germline sex determination is not. Here, we used the transgenic-based CRISPR/Cas9 genome editing system to study [...] Read more.
The domesticated silkworm is an economically important insect that is widely used as a lepidopteran insect model. Although somatic sex determination in the silkworm is well characterized, germline sex determination is not. Here, we used the transgenic-based CRISPR/Cas9 genome editing system to study the function of the Ovo gene in Bombyx mori. BmOvo is the homolog of a factor important in germline sex determination in Drosophila melanogaster. BmOvo mutants had abnormally shaped eggs that were disordered in the ovarioles, and gonad development was abnormal. Interestingly, wing discs and wings did not develop properly, and most of the mutants failed to eclose. Gene expression analyses by qRT-PCR showed that BmOvo gene was highly expressed in the wing disc and epidermis. Genes involved in the WNT signaling pathway and wing development genes BmWCP10 and BmE74 were downregulated in the BmOvo mutants when compared with wild-type animals. These results demonstrate that the BmOvo gene product plays an important role in wing metamorphosis. Thus, this study provides new insights into the multiple functions of BmOvo beyond germline sex determination. Full article
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Open AccessArticle
Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies
Insects 2019, 10(8), 253; https://doi.org/10.3390/insects10080253 - 16 Aug 2019
Viewed by 601
Abstract
Background: North American monarchs (Danaus plexippus) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (Asclepias curassavica) is planted in the southern [...] Read more.
Background: North American monarchs (Danaus plexippus) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (Asclepias curassavica) is planted in the southern coastal United States. An important question is whether exposure to exotic milkweed alters monarch migratory physiology, particularly the ability to enter and remain in the hormonally-induced state of reproductive diapause, whereby adults delay reproductive maturity. Cued by cooler temperatures and shorter photoperiods, diapause is a component of the monarch’s migratory syndrome that includes directional flight behavior, lipid accumulation, and the exceptional longevity of the migratory generation. Methods: Here, we experimentally test how exposure to tropical milkweed during the larval and adult stages influences monarch reproductive status during fall migration. Caterpillars reared under fall-like conditions were fed tropical versus native milkweed diets, and wild adult migrants were placed in outdoor flight cages with tropical milkweed, native milkweed, or no milkweed. Results: We found that monarchs exposed to tropical milkweed as larvae were more likely to be reproductively active (exhibit mating behavior in males and develop mature eggs in females) compared to monarchs exposed to native milkweed. Among wild-caught fall migrants, females exposed to tropical milkweed showed greater egg development than females exposed to native or no milkweed, although a similar response was not observed for males. Conclusions: Our study provides evidence that exposure to tropical milkweed can increase monarch reproductive activity, which could promote continued residency at year-round breeding sites and decrease monarch migratory propensity. Full article
(This article belongs to the Special Issue Impact of Introduced Plants on Insects)
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Open AccessArticle
Vertical and Horizontal Trophic Networks in the Aroid-Infesting Insect Community of Los Tuxtlas Biosphere Reserve, Mexico
Insects 2019, 10(8), 252; https://doi.org/10.3390/insects10080252 - 15 Aug 2019
Viewed by 429
Abstract
Insect-aroid interaction studies have focused largely on pollination systems; however, few report trophic interactions with other herbivores. This study features the endophagous insect community in reproductive aroid structures of a tropical rainforest of Mexico, and the shifting that occurs along an altitudinal gradient [...] Read more.
Insect-aroid interaction studies have focused largely on pollination systems; however, few report trophic interactions with other herbivores. This study features the endophagous insect community in reproductive aroid structures of a tropical rainforest of Mexico, and the shifting that occurs along an altitudinal gradient and among different hosts. In three sites of the Los Tuxtlas Biosphere Reserve in Mexico, we surveyed eight aroid species over a yearly cycle. The insects found were reared in the laboratory, quantified and identified. Data were analyzed through species interaction networks. We recorded 34 endophagous species from 21 families belonging to four insect orders. The community was highly specialized at both network and species levels. Along the altitudinal gradient, there was a reduction in richness and a high turnover of species, while the assemblage among hosts was also highly specific, with different dominant species. Our findings suggest that intrinsic plant factors could influence their occupation, and that the coexistence of distinct insect species in the assemblage could exert a direct or indirect influence on their ability to colonize such resources. Full article
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Open AccessArticle
Morphology and Distribution of the Antennal Sensilla of Two Species, Megalurothrips usitatus and Thrips palmi (Thysanoptera: Thripidae)
Insects 2019, 10(8), 251; https://doi.org/10.3390/insects10080251 - 15 Aug 2019
Viewed by 404
Abstract
The morphology and distribution of the antennal sensilla of Megalurothrips usitatus Bagnall and Thrips palmi Karny were examined using scanning electron microscopy (SEM). These are serious pests of various economically important crops, and their antennae are important in chemical communication. The antennae of [...] Read more.
The morphology and distribution of the antennal sensilla of Megalurothrips usitatus Bagnall and Thrips palmi Karny were examined using scanning electron microscopy (SEM). These are serious pests of various economically important crops, and their antennae are important in chemical communication. The antennae of both species consist of a scape, pedicel, and flagellum, but the flagellum of M. usitatus is made up of six sub-segments, whereas that of T. palmi consists of five sub-segments. Seven morphological sensilla types, including Böhm bristle (BB), sensilla campaniformia (Sca), three types of sensilla basiconica (Sb1, Sb2 and Sb3), two types of sensilla chaetica (Sch1 and Sch2), sensilla styloconica (Sst), sensilla trichodea (St), and sensilla cavity (Scav), were recorded in both species. The scape and pedicels exhibited Sch1, BB and Sca. The flagellum exhibited two types of Sch, three types of Sb, St, Sst and Scav. Based on these results, the putative function of the sensilla of M. usitatus and T. palmi are also discussed. Full article
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Open AccessArticle
First Description of the Adult Male of the Gall-Like Scale Insect Allokermes galliformis (Riley) (Hemiptera: Coccomorpha: Kermesidae)
Insects 2019, 10(8), 250; https://doi.org/10.3390/insects10080250 - 14 Aug 2019
Viewed by 413
Abstract
The adult male of Allokermes galliformis (Riley, 1881) (Hemiptera: Coccomorpha: Kermesidae) is described for the first time in Colorado, United States of America. This scale insect species recently emerged as a significant pest of red oaks in Colorado through its causative role in [...] Read more.
The adult male of Allokermes galliformis (Riley, 1881) (Hemiptera: Coccomorpha: Kermesidae) is described for the first time in Colorado, United States of America. This scale insect species recently emerged as a significant pest of red oaks in Colorado through its causative role in drippy blight disease. A description and illustration of the adult male characterize its key external morphological characteristics. Full article
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Open AccessArticle
Effects of Fine-Mesh Exclusion Netting on Pests of Blackberry
Insects 2019, 10(8), 249; https://doi.org/10.3390/insects10080249 - 14 Aug 2019
Viewed by 490
Abstract
Fine-mesh exclusion netting is a potential alternative to organic and conventional insecticide application to control numerous pests of fruit crops. We tested whether fine-mesh exclusion netting would reduce pest abundance and increase marketable yield compared to organic spinosad insecticide sprays in an organically [...] Read more.
Fine-mesh exclusion netting is a potential alternative to organic and conventional insecticide application to control numerous pests of fruit crops. We tested whether fine-mesh exclusion netting would reduce pest abundance and increase marketable yield compared to organic spinosad insecticide sprays in an organically managed blackberry field. At the completion of flowering, we covered blackberry rows with fine-mesh exclusion netting (ProtekNet) and treated alternating rows with an organic spinosad insecticide (Entrust™). Fine-mesh exclusion reduced green June beetle (Cotinus nitida Linnaeus) and bird presence and marginally reduced Japanese beetle (Popillia japonica Newman) presence on blackberry canes compared to organic spinosad insecticide treatment. Exclusion netting reduced the capture of spotted-wing Drosophila (Drosophila suzukii Matsumara; “SWD”) in baited traps in the fourth week of exclusion and reduced the overall number of SWD adults emerging from harvested blackberry fruits. Marketable yield in the fine-mesh exclusion treatments was two times higher than the organic spinosad insecticide treatment. These results suggest that fine-mesh exclusion netting is a functional pest control alternative to insecticide treatment for organic blackberry production. Full article
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Open AccessArticle
High-Resolution Profiling of Gut Bacterial Communities in an Invasive Beetle using PacBio SMRT Sequencing System
Insects 2019, 10(8), 248; https://doi.org/10.3390/insects10080248 - 14 Aug 2019
Viewed by 456
Abstract
Dendroctonus valens, an invasive bark beetle, has caused severe damage to Chinese forests. Previous studies have highlighted the importance of the gut microbiota and its fundamental role in host fitness. Culture-dependent and culture-independent methods have been applied in analyzing beetles’ gut microbiota. [...] Read more.
Dendroctonus valens, an invasive bark beetle, has caused severe damage to Chinese forests. Previous studies have highlighted the importance of the gut microbiota and its fundamental role in host fitness. Culture-dependent and culture-independent methods have been applied in analyzing beetles’ gut microbiota. The former method cannot present a whole picture of the community, and the latter mostly generates short read lengths that cannot be assigned to species. Here, the PacBio sequencing system was utilized to capture full-length 16S rRNA sequences in D. valens gut throughout its ontogeny. A total of eight phyla, 55 families, 102 genera, and 253 species were identified. Bacterial communities in colonized beetles have the greatest richness but the lowest evenness in all life stages, which is different from those in young larvae. Pseudomonas sp., Serratia liquefaciens possess high abundance throughout its ontogeny and may serve as members of the core bacteriome. A phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis predicted that gut microbiota in larvae are rich in genes involved in carbohydrate, energy metabolism. Gut microbiota in both larvae and colonized beetles are rich in xenobiotics and terpenoids biodegradation, which are decreased in dispersal beetles. Considering that the results are based mainly on the analysis of 16S rRNA sequencing and PICRUSt prediction, further confirmation is needed to improve the knowledge of the gut microbiota in D. valens and help to resolve taxonomic uncertainty at the species level. Full article
(This article belongs to the Special Issue Ecology and Management of Invasive Insects in Forest Ecosystems)
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Open AccessReview
Managing Floral Resources in Apple Orchards for Pest Control: Ideas, Experiences and Future Directions
Insects 2019, 10(8), 247; https://doi.org/10.3390/insects10080247 - 11 Aug 2019
Viewed by 550
Abstract
Functional biodiversity is of fundamental importance for pest control. Many natural enemies rely on floral resources to complete their life cycle. Farmers need to ensure the availability of suitable and sufficient floral biodiversity. This review summarizes 66 studies on the management of floral [...] Read more.
Functional biodiversity is of fundamental importance for pest control. Many natural enemies rely on floral resources to complete their life cycle. Farmers need to ensure the availability of suitable and sufficient floral biodiversity. This review summarizes 66 studies on the management of floral biodiversity in apple orchards, published since 1986. Approaches followed different degrees of intervention: short-term practices (mowing regime and weed maintenance, cover crops), establishment of durable ecological infrastructures (perennial flower strips, hedgerows) and re-design of the crop system (intercropping, agroforestry). Although short-term practices did not always target the nutrition of natural enemies by flowering plants, living conditions for them (alternative prey, provision of habitat) were often improved. Perennial flower strips reliably enhanced natural enemies and techniques for their introduction continuously developed. Resident natural enemies and their impact in pest control reacted positively to the introduction of a more diversified vegetation, whereas the response of very mobile organisms was often not directly linked to the measures taken. A careful selection and management of plants with particular traits exploitable by most natural enemies emerged as a key-point for success. Now the elaborated design of such measures needs to be adopted by stakeholders and policy makers to encourage farmers to implement these measures in their orchards. Full article
(This article belongs to the Special Issue Pest Control in Fruit Trees)
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Open AccessArticle
Aedes albopictus Adult Medium Mass Rearing for SIT Program Development
Insects 2019, 10(8), 246; https://doi.org/10.3390/insects10080246 - 09 Aug 2019
Viewed by 479
Abstract
For the production of several hundred thousands of Aedes albopictus sterile males for the implementation of a Sterile Insect Technique (SIT) program, no costly mass-rearing equipment is needed during the initial phases, as optimized rearing at laboratory scale can be sufficient for the [...] Read more.
For the production of several hundred thousands of Aedes albopictus sterile males for the implementation of a Sterile Insect Technique (SIT) program, no costly mass-rearing equipment is needed during the initial phases, as optimized rearing at laboratory scale can be sufficient for the first steps. The aim of this study was to maximize the egg production by optimizing adult rearing methods for Ae. albopictus. The effect of parameters such as male/female ratio, density of adults, membrane type for blood feeding, quantity of blood delivered, continuous or discontinuous blood feeding, and surface of substrates for egg laying on overall egg production was tested to find optimized conditions. Based on the number of eggs produced per cage in response to the parameters tested, the optimum cage set-up was seen to be 1500 adults in a 30 × 30 × 30 cm cage with a male/female sex ratio of 1:3, fed by fresh bovine blood for periods of 30 min using a cellulose membrane covering a 10 cm stainless steel plate heated by a Hemotek device, and the provision of five oviposition cups to collect eggs. With this set-up, production per cage can reach a maximum of 35,000 eggs per week. Full article
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Open AccessArticle
Genome-Wide Identification of Long Non-Coding RNAs and Their Regulatory Networks Involved in Apis mellifera ligustica Response to Nosema ceranae Infection
Insects 2019, 10(8), 245; https://doi.org/10.3390/insects10080245 - 09 Aug 2019
Viewed by 562
Abstract
Long non-coding RNAs (lncRNAs) are a diverse class of transcripts that structurally resemble mRNAs but do not encode proteins, and lncRNAs have been proven to play pivotal roles in a wide range of biological processes in animals and plants. However, knowledge of expression [...] Read more.
Long non-coding RNAs (lncRNAs) are a diverse class of transcripts that structurally resemble mRNAs but do not encode proteins, and lncRNAs have been proven to play pivotal roles in a wide range of biological processes in animals and plants. However, knowledge of expression patterns and potential roles of honeybee lncRNA response to Nosema ceranae infection is completely unknown. Here, we performed whole transcriptome strand-specific RNA sequencing of normal midguts of Apis mellifera ligustica workers (Am7CK, Am10CK) and N. ceranae-inoculated midguts (Am7T, Am10T), followed by comprehensive analyses using bioinformatic and molecular approaches. A total of 6353 A. m. ligustica lncRNAs were identified, including 4749 conserved lncRNAs and 1604 novel lncRNAs. These lncRNAs had minimal sequence similarities with other known lncRNAs in other species; however, their structural features were similar to counterparts in mammals and plants, including shorter exon and intron length, lower exon number, and lower expression level, compared with protein-coding transcripts. Further, 111 and 146 N. ceranae-responsive lncRNAs were identified from midguts at 7-days post-inoculation (dpi) and 10 dpi compared with control midguts. Twelve differentially expressed lncRNAs (DElncRNAs) were shared by Am7CK vs. Am7T and Am10CK vs. Am10T comparison groups, while the numbers of unique DElncRNAs were 99 and 134, respectively. Functional annotation and pathway analysis showed that the DElncRNAs may regulate the expression of neighboring genes by acting in cis and trans fashion. Moreover, we discovered 27 lncRNAs harboring eight known miRNA precursors and 513 lncRNAs harboring 2257 novel miRNA precursors. Additionally, hundreds of DElncRNAs and their target miRNAs were found to form complex competitive endogenous RNA (ceRNA) networks, suggesting that these DElncRNAs may act as miRNA sponges. Furthermore, DElncRNA-miRNA-mRNA networks were constructed and investigated, the results demonstrated that a portion of the DElncRNAs were likely to participate in regulating the host material and energy metabolism as well as cellular and humoral immune host responses to N. ceranae invasion. Our findings revealed here offer not only a rich genetic resource for further investigation of the functional roles of lncRNAs involved in the A. m. ligustica response to N. ceranae infection, but also a novel insight into understanding the host-pathogen interaction during honeybee microsporidiosis. Full article
(This article belongs to the Special Issue Biology of Social Insect Diseases)
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Open AccessArticle
The Year of the Honey Bee (Apis mellifera L.) with Respect to Its Physiology and Immunity: A Search for Biochemical Markers of Longevity
Insects 2019, 10(8), 244; https://doi.org/10.3390/insects10080244 - 07 Aug 2019
Viewed by 633
Abstract
It has been known for many years that in temperate climates the European honey bee, Apis mellifera, exists in the form of two distinct populations within the year, short-living summer bees and long-living winter bees. However, there is only limited knowledge about [...] Read more.
It has been known for many years that in temperate climates the European honey bee, Apis mellifera, exists in the form of two distinct populations within the year, short-living summer bees and long-living winter bees. However, there is only limited knowledge about the basic biochemical markers of winter and summer populations as yet. Nevertheless, the distinction between these two kinds of bees is becoming increasingly important as it can help beekeepers to estimate proportion of long-living bees in hives and therefore in part predict success of overwintering. To identify markers of winter generations, we employed the continuous long-term monitoring of a single honey bee colony for almost two years, which included measurements of physiological and immunological parameters. The results showed that the total concentration of proteins, the level of vitellogenin, and the antibacterial activity of haemolymph are the best three of all followed parameters that are related to honey bee longevity and can therefore be used as its markers. Full article
(This article belongs to the Special Issue New Perspectives on Honeybee Health)
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Open AccessArticle
Differences in the Development of Internal Reproductive Organs, Feeding Amount and Nutrient Storage between Pre-Diapause and Pre-Reproductive Harmonia axyridis Adults
Insects 2019, 10(8), 243; https://doi.org/10.3390/insects10080243 - 06 Aug 2019
Viewed by 450
Abstract
Diapause control is one of the successful methods for long-term cold storage of biological control organisms without decreasing their fitness. Sufficient preparation before diapause is essential for successful diapause initiation and maintenance. Harmonia axyridis, an important biocontrol agent in its native place, [...] Read more.
Diapause control is one of the successful methods for long-term cold storage of biological control organisms without decreasing their fitness. Sufficient preparation before diapause is essential for successful diapause initiation and maintenance. Harmonia axyridis, an important biocontrol agent in its native place, can enter reproductive diapause for overwintering. However, the key preparatory events before diapause in H. axyridis, such as specific developmental trajectory, timing, and physiological changes, remain unclear. We compared differences in the development of internal reproductive organs, feeding amount and nutrient storage between pre-diapause and pre-reproductive adult H. axyridis which had been reared at 20 °C under a short-day (10L:14D) and long-day (14L:10D) condition, respectively. The results showed that there were obvious morphological differences in internal reproductive organs of diapause and reproductive H. axyridis. The development of internal reproductive organs was suppressed at early adult stage in pre-diapause beetles compared to pre-reproductive beetles. Feeding amount in both pre-diapause and pre-reproductive beetles increased for more than ten days after eclosion. The feeding amount of pre-diapause beetles sharply decreased from the 15th day after eclosion in females and the 14th day after eclosion in males, which implied the initiation of diapause. During the pre-diapause stage, carbohydrates and lipids were mainly accumulated by females, whereas males mainly accumulated carbohydrates. Our results not only provide basic information about the diapause process of pre-diapause stage, but also give tips to better utilization of diapause strategy during mass production and storage of H. axyridis. Full article
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Open AccessArticle
Efficacy of Spinosad Granules and Lambda-Cyhalothrin Contrasts with Reduced Performance of Temephos for Control of Aedes spp. in Vehicle Tires in Veracruz, Mexico
Insects 2019, 10(8), 242; https://doi.org/10.3390/insects10080242 - 06 Aug 2019
Viewed by 496
Abstract
The present study examined the efficacy of λ-cyhalothrin, pyriproxyfen and granular formulations of spinosad and temephos for the control of mosquito larvae present in experimental tires in Veracruz State, Mexico in the period 2015–2016. Both λ-cyhalothrin and spinosad granules provided control of larvae [...] Read more.
The present study examined the efficacy of λ-cyhalothrin, pyriproxyfen and granular formulations of spinosad and temephos for the control of mosquito larvae present in experimental tires in Veracruz State, Mexico in the period 2015–2016. Both λ-cyhalothrin and spinosad granules provided control of larvae and pupae of Aedes aegypti, Ae. albopictus and Culex spp. in used tires in Veracruz State, Mexico, over a 9–12 week period, although numbers of Culex were low. The numbers of Aedes larvae + pupae in pyriproxyfen and temephos-treated tires were slightly less than half of the untreated control tires, probably a result the pupicidal characteristics of pyriproxyfen and possible resistance in the case of temephos. Spinosad was less harmful to predatory Toxorhynchites spp. than λ-cyhalothrin or temephos. The reduced susceptibility to temephos in Aedes populations was confirmed at five other sites in Veracruz. Public health authorities should consider incorporating spinosad as a larvicide in coastal areas at a high risk of dengue, chikungunya and Zika outbreaks in this region. Full article
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Open AccessReview
Tools in the Investigation of Volatile Semiochemicals on Insects: From Sampling to Statistical Analysis
Insects 2019, 10(8), 241; https://doi.org/10.3390/insects10080241 - 06 Aug 2019
Viewed by 635
Abstract
The recognition of volatile organic compounds (VOCs) involved in insect interactions with plants or other organisms is essential for constructing a holistic comprehension of their role in ecology, from which the implementation of new strategies for pest and disease vector control as well [...] Read more.
The recognition of volatile organic compounds (VOCs) involved in insect interactions with plants or other organisms is essential for constructing a holistic comprehension of their role in ecology, from which the implementation of new strategies for pest and disease vector control as well as the systematic exploitation of pollinators and natural enemies can be developed. In the present paper, some of the general methods employed in this field are examined, focusing on their available technologies. An important part of the investigations conducted in this context begin with VOC collection directly from host organisms, using classical extraction methods, by the employment of adsorption materials used in solid-phase micro extraction (SPME) and direct-contact sorptive extraction (DCSE) and, subsequently, analysis through instrumental analysis techniques such as gas chromatography (GC), nuclear magnetic resonance (NMR) and mass spectrometry (MS), which provide crucial information for determining the chemical identity of volatile metabolites. Behavioral experiments, electroantennography (EAG), and biosensors are then carried out to define the semiochemicals with the best potential for performing relevant functions in ecological relationships. Chemical synthesis of biologically-active VOCs is alternatively performed to scale up the amount to be used in different purposes such as laboratory or field evaluations. Finally, the application of statistical analysis provides tools for drawing conclusions about the type of correlations existing between the diverse experimental variables and data matrices, thus generating models that simplify the interpretation of the biological roles of VOCs. Full article
(This article belongs to the Special Issue Semiochemicals and Insect Behavior)
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Open AccessArticle
Subterranean Termite Social Alarm and Hygienic Responses to Fungal Pathogens
Insects 2019, 10(8), 240; https://doi.org/10.3390/insects10080240 - 05 Aug 2019
Viewed by 586
Abstract
In social insects, alerting nestmates to the presence of a pathogen should be critical for limiting its spread and initiating social mechanisms of defense. Here we show that subterranean termites use elevated vibratory alarm behavior to help prevent fatal fungal infections. The elevated [...] Read more.
In social insects, alerting nestmates to the presence of a pathogen should be critical for limiting its spread and initiating social mechanisms of defense. Here we show that subterranean termites use elevated vibratory alarm behavior to help prevent fatal fungal infections. The elevated alarm leads to elevated social hygiene. This requires that termites coalesce so that they can groom each other’s cuticular surfaces of contaminating conidial spores. Groups of 12 Reticulitermes flavipes workers varied in their response when immersed in conidia solutions of nine different strains of Metarhizium. Pathogen alarm displays of short 2–7-second bursts of rapid longitudinal oscillatory movement (LOM), observed over 12 min following a fungal challenge, were positively correlated with the time that workers spent aggregated together grooming each other. The frequency of these LOMs was inversely correlated with fatal fungal infections. The variation in fatalities appeared to be largely attributable to a differential response to Metarhizium brunneum and Metarhizium robertsii in the time spent in aggregations and the frequency of allogrooming. Isolated workers challenged with conidia did not display LOMs, which suggests that the alarm is a conditional social response. LOMs appear to help signal the presence of fungal pathogens whose virulence depends on the level of this emergency alert. Full article
(This article belongs to the Special Issue Biology of Social Insect Diseases)
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Open AccessArticle
Host Associations of Culex (Melanoconion) atratus (Diptera: Culicidae) and Culex (Melanoconion) pilosus from Florida, USA
Insects 2019, 10(8), 239; https://doi.org/10.3390/insects10080239 - 03 Aug 2019
Viewed by 669
Abstract
Characterizing the host-use patterns of mosquitoes is an essential component of understanding the transmission dynamics of mosquito-vectored pathogens. The host associations of two species of the medically important Culex subgenus Melanoconion, Culex atratus, and Culex pilosus are unknown or unclear, respectively. Both [...] Read more.
Characterizing the host-use patterns of mosquitoes is an essential component of understanding the transmission dynamics of mosquito-vectored pathogens. The host associations of two species of the medically important Culex subgenus Melanoconion, Culex atratus, and Culex pilosus are unknown or unclear, respectively. Both species have wide neotropical distributions. In the United States of America (USA), Culex pilosus occurs throughout the southeastern coastal plain, while Culex atratus is restricted to the southern Florida Peninsula. Using PCR-based blood meal analysis, we investigated the host associations of Culex atratus and Culex pilosus that were collected from Everglades National Park, Florida, USA We identified the host species of 208 Culex atratus and 168 Culex pilosus. Both species were narrowly associated with reptilian host species, particularly native and non-native lizards of the genus Anolis. Sampled Culex atratus exclusively fed on reptilian hosts, with >99% of blood meals derived from Anolis lizards. Culex pilosus fed predominantly from reptiles, but avian and mammalian blood meals were also detected. Of these, 92% of blood meals were derived from Anolis species. For both species, Anolis sagrei, an invasive exotic lizard in Florida, was the most frequently detected host species. These data indicate that Culex atratus and Culex pilosus are specialists of reptilian hosts, particularly Anolis lizards. Full article
(This article belongs to the Special Issue Vectors and Vector-borne Diseases)
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Open AccessArticle
Detection of Leishmania and Trypanosoma DNA in Field-Caught Sand Flies from Endemic and Non-Endemic Areas of Leishmaniasis in Southern Thailand
Insects 2019, 10(8), 238; https://doi.org/10.3390/insects10080238 - 02 Aug 2019
Viewed by 611
Abstract
Phlebotomine sand flies are tiny, hairy, blood-sucking nematoceran insects that feed on a wide range of hosts. They are known as a principal vector of parasites, responsible for human and animal leishmaniasis worldwide. In Thailand, human autochthonous leishmaniasis and trypanosomiasis have been reported. [...] Read more.
Phlebotomine sand flies are tiny, hairy, blood-sucking nematoceran insects that feed on a wide range of hosts. They are known as a principal vector of parasites, responsible for human and animal leishmaniasis worldwide. In Thailand, human autochthonous leishmaniasis and trypanosomiasis have been reported. However, information on the vectors for Leishmania and Trypanosoma in the country is still limited. Therefore, this study aims to detect Leishmania and Trypanosoma DNA in field-caught sand flies from endemic areas (Songkhla and Phatthalung Provinces) and non-endemic area (Chumphon Province) of leishmaniasis. A total of 439 sand flies (220 females and 219 males) were collected. Head and genitalia dissection of female sandflies were done for morphology identification, and the remaining parts of those sand flies were then used for the detection of Leishmania and Trypanosoma parasites. The DNA was extracted from individual female sand flies. Polymerase chain reaction (PCR) anneal, specific to the ITS1 and SSU rRNA gene regions, was used to detect Leishmania and Trypanosoma DNA, respectively. The positive PCR products were cloned and sequenced. The results showed that the female sand fly species in this study consisted of Sergentomyia khawi (35.9%); Se. anodontis (23.6%); Phlebotomus betisi (18.6%); Ph. kiangsuensis (9.5%); Ph. asperulus (6.4%); Se. barraudi (2.3%); 0.9% of each Se. indica, Ph. stantoni, and Ph. major major; and 0.5% of each Se. sylvatica and Ph. mascomai. The PCR and sequence analysis were able to detect Leishmania and Trypanosoma DNA in sand fly samples, which were identified as L. martiniquensis, 1/220 (0.45%) in Se. khawi, 3/220 (1.36%) of T. noyesi in Se. anodontis, and Ph. asperulus. Fourteen (6.36%) of the unidentified trypanosome species in Se. khawi, Se. indica, Se. anodontis, Ph. asperulus, and Ph. betisi were found in all of the areas of this study. Interestingly, we found a 1/220 (0.45%) co-infection sample of L. martiniquensis and Trypanosoma in Se. khawi from Songkhla Province. These data indicate that several species of sand flies might be potential vectors of Leishmania and Trypanosoma parasites in southern Thailand. However, more extensive study for potential vectors using a larger number of sand flies should be conducted to prove whether these sand flies can be natural vectors of leishmaniasis and trypanosomiasis in both humans and animals. In addition, our study could be useful for the future study of infection prevention, including effective vector control for leishmaniasis and trypanosomiasis in Thailand. Full article
(This article belongs to the Special Issue Vectors and Vector-borne Diseases)
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Open AccessArticle
Notes on the Nest Architecture and Colony Composition in Winter of the Yellow-Legged Asian Hornet, Vespa velutina Lepeletier 1836 (Hym.: Vespidae), in Its Introduced Habitat in Galicia (NW Spain)
Insects 2019, 10(8), 237; https://doi.org/10.3390/insects10080237 - 02 Aug 2019
Viewed by 709
Abstract
Fifteen years ago, at least one multimated female yellow-legged Asian hornet (Vespa velutina Lepeletier 1836) arrived in France, giving rise to a pan-European invasion, altering the environment, affecting ecosystem processes, and impacting society. During winter, V. velutina nests (n = 3) were [...] Read more.
Fifteen years ago, at least one multimated female yellow-legged Asian hornet (Vespa velutina Lepeletier 1836) arrived in France, giving rise to a pan-European invasion, altering the environment, affecting ecosystem processes, and impacting society. During winter, V. velutina nests (n = 3) were collected in Galicia and data on internal and external aspects of the nests and the colony as a whole were collected. The whole colony population (WCPN; adult insects, larvae, and pupae in percentages) was as follows: nest A: n = 176 (49%, 3%, and 48%); nest B: n = 1979 (52%, 36%, and 12%); and nest C: n = 662 (5%, 27%, and 8%). The adult insect population (IAPN; males, workers, and gynes in percentages) was as follows: nest A: n = 87 (11%, 66%, and 23%); nest B: n = 1021 (3%, 62%, and 35%); and nest C: n = 430 (20%, 73%, and 7%). As a small number of queens is sufficient for a population to develop, it is necessary to avoid continued spread by deactivating and removing all nests, even those detected in winter. This practice can be of greatest importance in border areas where V. velutina is expanding into new territory. Full article
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Open AccessArticle
Population Genetics of Bactrocera minax (Diptera: Tephritidae) in China Based on nad4 Gene Sequence
Insects 2019, 10(8), 236; https://doi.org/10.3390/insects10080236 - 02 Aug 2019
Viewed by 433
Abstract
Bactrocera minax (Enderlein) (Diptera: Tephritidae) is an important citrus pest in Asia with a non-uniform distribution. In some locations, it had been reported to occur but was either eradicated or disappeared itself. To understand species dispersal of B. minax, we collected and [...] Read more.
Bactrocera minax (Enderlein) (Diptera: Tephritidae) is an important citrus pest in Asia with a non-uniform distribution. In some locations, it had been reported to occur but was either eradicated or disappeared itself. To understand species dispersal of B. minax, we collected and analyzed 359 individuals from 18 localities in China. One mitochondrial DNA gene fragment (nad4) was used to investigate the genetic diversity and population genetic structure of B. minax. The populations were divided by phylogenetic analyses and statistical parsimony haplotype networks into three branches: a Central China (CC) branch, a Western China (WC) branch, and a Southern China (SC) branch. A total of 93 variable sites (15.6% of the 595 bp alignment) and 91 unique haplotypes were observed in the 359 individuals scored from the nad4 gene of the 18 B. minax populations. This indicated that B. minax had a high level of genetic diversity. These populations also showed a discrete distribution in both the scatter plots of genetic versus geographical distance for pairwise population comparisons and the median-joining network of haplotypes, which revealed the strong genetic structure of B. minax. Full article
(This article belongs to the Special Issue Population Genetics of Insects)
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Open AccessArticle
Standardized Ixodid Tick Survey in Mainland Florida
Insects 2019, 10(8), 235; https://doi.org/10.3390/insects10080235 - 01 Aug 2019
Cited by 1 | Viewed by 473
Abstract
A statewide survey of questing ixodid ticks in mainland Florida was developed consistent with U.S. CDC standards to maximize the amount of epidemiologic and environmental data gathered. Survey sites were stratified by climatic zones and proportional to recognized land cover categories. A total [...] Read more.
A statewide survey of questing ixodid ticks in mainland Florida was developed consistent with U.S. CDC standards to maximize the amount of epidemiologic and environmental data gathered. Survey sites were stratified by climatic zones and proportional to recognized land cover categories. A total of 560 transects on 41 sites within the state were sampled repeatedly by flagging between 2015 and 2018. Four tick species were collected; Amblyomma americanum, Amblyomma maculatum, Ixodes scapularis and Dermacentor variabilis. All species were more commonly found in northern and central regions of the state than in southern and western regions. Adult I. scapularis were active from autumn through spring and complementary to adult A. americanum and D. variabilis. Standardized survey methods help reduce sampling biases and better characterize risk from the species surveyed. However, differences in the attractiveness of collection methods for different tick species makes cross-species comparisons a continuing challenge. Full article
(This article belongs to the Special Issue Tick Surveillance and Tick-borne Diseases)
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Open AccessArticle
Varied Effects of Tending Ant Species on the Development of Facultatively Myrmecophilous Lycaenid Butterfly Larvae
Insects 2019, 10(8), 234; https://doi.org/10.3390/insects10080234 - 01 Aug 2019
Viewed by 444
Abstract
Ants often tend and protect the larvae of various myrmecophilous lycaenid species, which influences the fitness of butterflies by altering their growth and developmental time. Tending produces diverse effects depending on lycaenid sex and the lycaenid/ant species combination. Effects are widely variable, especially [...] Read more.
Ants often tend and protect the larvae of various myrmecophilous lycaenid species, which influences the fitness of butterflies by altering their growth and developmental time. Tending produces diverse effects depending on lycaenid sex and the lycaenid/ant species combination. Effects are widely variable, especially in facultatively myrmecophilous lycaenids such as Plebejus argyrognomon praeterinsularis, because they are associated with several ant species and can survive without any ant tending. We studied the effects of ant tending on the adult body mass and larval developmental time of P. argyrognomon praeterinsularis. Female larvae grew significantly heavier as adults when tended by Camponotus japonicus rather than by either Lasius japonicus or no ant species. Ant tending did not affect the body mass of adult males or the developmental time of either male or female larvae. Thus, tending by C. japonicus could increase the fitness of P. argyrognomon praeterinsularis by increasing the mass of females without prolonging the duration of vulnerable immature stages, because larger females generally lay more eggs. This means that even facultatively myrmecophilous lycaenids might gain fitness benefits from particular ant species, which could be important in the conservation and management of at-risk species of facultatively myrmecophilous lycaenids. Full article
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Open AccessReview
Impact of Biotic and Abiotic Stressors on Managed and Feral Bees
Insects 2019, 10(8), 233; https://doi.org/10.3390/insects10080233 - 01 Aug 2019
Viewed by 710
Abstract
Large-scale declines in bee abundance and species richness over the last decade have sounded an alarm, given the crucial pollination services that bees provide. Population dips have specifically been noted for both managed and feral bee species. The simultaneous increased cultivation of bee-dependent [...] Read more.
Large-scale declines in bee abundance and species richness over the last decade have sounded an alarm, given the crucial pollination services that bees provide. Population dips have specifically been noted for both managed and feral bee species. The simultaneous increased cultivation of bee-dependent agricultural crops has given rise to additional concern. As a result, there has been a surge in scientific research investigating the potential stressors impacting bees. A group of environmental and anthropogenic stressors negatively impacting bees has been isolated. Habitat destruction has diminished the availability of bee floral resources and nest habitats, while massive monoculture plantings have limited bee access to a variety of pollens and nectars. The rapid spread and increased resistance buildup of various bee parasites, pathogens, and pests to current control methods are implicated in deteriorating bee health. Similarly, many pesticides that are widely applied on agricultural crops and within beehives are toxic to bees. The global distribution of honey bee colonies (including queens with attendant bees) and bumble bee colonies from crop to crop for pollination events has been linked with increased pathogen stress and increased competition with native bee species for limited resources. Climatic alterations have disrupted synchronous bee emergence with flower blooming and reduced the availability of diverse floral resources, leading to bee physiological adaptations. Interactions amongst multiple stressors have created colossal maladies hitting bees at one time, and in some cases delivering additive impacts. Initiatives including the development of wild flower plantings and assessment of pesticide toxicity to bees have been undertaken in efforts to ameliorate current bee declines. In this review, recent findings regarding the impact of these stressors on bees and strategies for mitigating them are discussed. Full article
Open AccessArticle
A Re-Evaluation of Olive Fruit Fly Organophosphate-Resistant Ace Alleles in Iberia, and Field-Testing Population Effects after in-Practice Dimethoate Use
Insects 2019, 10(8), 232; https://doi.org/10.3390/insects10080232 - 01 Aug 2019
Viewed by 460
Abstract
The management of the olive fruit fly (Bactrocera oleae) is traditionally based upon the use of organophosphate insecticides, mainly dimethoate. In this evolutionary arms race between man and pest, the flies have adapted a pesticide resistance, implying two point-mutations of the [...] Read more.
The management of the olive fruit fly (Bactrocera oleae) is traditionally based upon the use of organophosphate insecticides, mainly dimethoate. In this evolutionary arms race between man and pest, the flies have adapted a pesticide resistance, implying two point-mutations of the Ace gene -I214V and G488S- and a 9bp deletion -Δ3Q. We revisited 11 Iberian locations to evaluate this adaptation of organophosphate (OP)-resistant alleles through amplicon sequencing. Screening for populations where the wild type is prevalent allows an identification of hotspots for targeted mitigation measures; we have hence refined the scale to the region with the lowest OP-resistant alleles frequency 71 locations were sampled and individuals checked using a fast and low-cost allele-specific-primer polymerase chain reaction (ASP-PCR) method]. An increase in Ace gene point-mutations was observed, and the Δ3Q mutation remains undetected. The lowest frequencies of the OP-resistant alleles remain in the west, underlining the hypothesis of an introduction of resistance from eastern Mediterranean areas. A field test was performed by sampling the fly population before and after in-practice dimethoate application. A clear reduction in olive fruit fly numbers was observed, with no relevant changes in the genotypic frequencies of the resistance alleles. The findings are discussed in frame of the type and intensity of the selection pressure that has led to the adaptation to resistance and its consequences from the producer perspective. Full article
(This article belongs to the Special Issue Monitoring and Detection of Insect Resistance)
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Open AccessArticle
Congruence Between Molecular Data and Morphology: Phylogenetic Position of Senodoniini (Coleoptera: Elateridae)
Insects 2019, 10(8), 231; https://doi.org/10.3390/insects10080231 - 01 Aug 2019
Viewed by 794
Abstract
Senodoniini is a small lineage of click beetles currently comprising 21 species in two genera, distributed in the Himalayas and East and Southeast Asia. The definition and limits of this group have changed considerably during its history. Recent authors treat Senodoniini as a [...] Read more.
Senodoniini is a small lineage of click beetles currently comprising 21 species in two genera, distributed in the Himalayas and East and Southeast Asia. The definition and limits of this group have changed considerably during its history. Recent authors treat Senodoniini as a tribe within Dendrometrinae, usually close to Dimini, but this placement has never been rigorously tested. Here, we shed new light on the systematic position and limits of Senodoniini by performing a combined phylogenetic analysis of two nuclear and two mitochondrial molecular markers. Our results recovered Senodoniini not monophyletic, and placed them into the Lissominae complex, where they formed a clade with Austrelater Calder & Lawrence (Protelaterini). Molecular phylogeny is in agreement with the adult morphology. Additionally, we examined the morphology of a monotypic genus Rostricephalus Fleutiaux from Southeast Asia, which was previously classified in various Elateridae groups including Senodoniini, and its position was always uncertain. This genus shares morphological characters with Protelaterini. We provide morphological redescriptions as well as the figures of main diagnostic characters for Senodonia Laporte, Sossor Candèze, and Rostricephalus. Based on our results, we place these genera to Lissominae: Protelaterini, and hence synonymize Senodoniini Schenkling with Protelaterini Schwarz. Full article
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Open AccessArticle
Aedes aegypti Males as Vehicles for Insecticide Delivery
Insects 2019, 10(8), 230; https://doi.org/10.3390/insects10080230 - 01 Aug 2019
Viewed by 743
Abstract
Aedes aegypti continues to spread globally and remains a challenge to control, in part due to its ‘cryptic behavior’ in that it often deposits eggs (oviposits) in larval habitats that are difficult to find and treat using traditional methods. Auto-dissemination strategies target these [...] Read more.
Aedes aegypti continues to spread globally and remains a challenge to control, in part due to its ‘cryptic behavior’ in that it often deposits eggs (oviposits) in larval habitats that are difficult to find and treat using traditional methods. Auto-dissemination strategies target these cryptic breeding sites by employing mosquitoes to deliver lethal doses of insecticide. This report describes the initial field trials of an application known as Autodissemination Augmented by Males (ADAM), utilizing A. aegypti males dusted with pyriproxyfen (PPF). Findings presented here are drawn from both caged and field trial studies. Together, these trials examined for the ability of A. aegypti males to disseminate PPF and to impact field populations. PPF-dusted males were able to effectively deliver lethal doses of PPF to oviposition sites under the conditions tested. Results from field trials in Florida and California demonstrated reduced A. aegypti populations in treated areas, compared to areas where PPF-treated males were not released. These results indicate that the release of PPF-dusted A. aegypti males can impact A. aegypti populations as measured by both reduced larval survival and lower numbers of adult female A. aegypti. We propose the ADAM approach as an addition to existing mosquito control techniques targeting A. aegypti and other mosquitoes that utilize cryptic larval habitats. Full article
(This article belongs to the Special Issue Vectors and Vector-borne Diseases)
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Open AccessArticle
Synthesis of Known and New Host Plant Records of the Fijian Ginger Weevil, Elytroteinus geophilus (Lucas) (Coleoptera, Curculionidae, Cryptorhynchinae) Suggests a Preference for Starch-storing Plant Organs
Insects 2019, 10(8), 229; https://doi.org/10.3390/insects10080229 - 31 Jul 2019
Viewed by 524
Abstract
Elytroteinus geophilus (Lucas) is a polyphagous weevil that is widespread in the South Pacific islands and is known to cause damage to various crops with large nutrient storage structures such as kava, ginger, yellow passion fruit, yams and sweet potatoes. More significantly, E. [...] Read more.
Elytroteinus geophilus (Lucas) is a polyphagous weevil that is widespread in the South Pacific islands and is known to cause damage to various crops with large nutrient storage structures such as kava, ginger, yellow passion fruit, yams and sweet potatoes. More significantly, E. geophilus, the Fijian Ginger Weevil, has been linked, along with two wound invading fungal pathogens, to a passion fruit collar rot in Samoa. This species is considered a high-risk insect pest and it is included in the USDA’s prioritized offshore pest list. We report on new plant hosts and behavior of this weevil. The first new host record resulted from interception of this weevil in bulbs of Tropical Spider Lily (Crinum sp.) in Alabama. This interception initiated an examination of museum specimens and the literature that resulted in a second previously unreported host record (vanilla (Orchidaceae)) and a new behavioral trait for this weevil: the use of plant fibers to spin a cocoon for pupation. A synthesis of known host plants records is reported here and suggests a preference by this weevil of starch-storing plant organs. A distribution map and a differential diagnosis of the species is also provided. Full article
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Open AccessArticle
Yeast Species, Strains, and Growth Media Mediate Attraction of Drosophila suzukii (Diptera: Drosophilidae)
Insects 2019, 10(8), 228; https://doi.org/10.3390/insects10080228 - 31 Jul 2019
Viewed by 482
Abstract
Specific ecological interactions between insects and microbes have potential in the development of targeted pest monitoring or control techniques for the spotted wing drosophilid, Drosophila suzukii (Matsumura), an exotic invasive pest of soft fruit. To evaluate D. suzukii attraction to yeast species from [...] Read more.
Specific ecological interactions between insects and microbes have potential in the development of targeted pest monitoring or control techniques for the spotted wing drosophilid, Drosophila suzukii (Matsumura), an exotic invasive pest of soft fruit. To evaluate D. suzukii attraction to yeast species from preferred types of fruit, three yeasts were isolated from blackberry fruit and two yeasts from raspberry fruit and used to bait simple plastic bottle traps. Saccharomyces cerevisiae and Hanseniaspora uvarum were identified from blackberries, whereas a different H. uvarum strain was identified from raspberry. Yeast identification was based on sequence analysis of the D1/D2 domain of the large subunit 26S rRNA gene. Commercial baker’s yeast (S. cerevisiae) was similar or more effective for the capture of D. suzukii males and females than yeasts isolated from blackberry or raspberry when grown in sucrose. However, when grown in corn syrup, a strain of S. cerevisiae from blackberry captured the highest number of females and a strain of H. uvarum isolated from raspberry captured high numbers of males and females. Species of Candida, Hanseniaspora, and Pichia from a laboratory yeast collection did not outperform baker’s yeast in pairwise tests when grown in sucrose solution or yeast-peptone-dextrose medium. The raspberry strain of H. uvarum grown in corn syrup outperformed S. cerevisiae grown in sucrose, in terms of captures in baited traps under laboratory conditions. We conclude that yeast species, strain, and growth medium can have a marked influence on D. suzukii attraction to baited traps, a finding that could assist in the development of yeast-related monitoring or control techniques targeted at this pest. Full article
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Open AccessArticle
Impacts of Deciduous Leaf Litter and Snow Presence on Nymphal Ixodes scapularis (Acari: Ixodidae) Overwintering Survival in Coastal New England, USA
Insects 2019, 10(8), 227; https://doi.org/10.3390/insects10080227 - 30 Jul 2019
Viewed by 567
Abstract
Blacklegged ticks (Ixodes scapularis Say) are the vector for pathogens that cause more cases of human disease than any other arthropod. Lyme disease is the most common, caused by the bacterial spirochete Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt, and Brenner) in the [...] Read more.
Blacklegged ticks (Ixodes scapularis Say) are the vector for pathogens that cause more cases of human disease than any other arthropod. Lyme disease is the most common, caused by the bacterial spirochete Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt, and Brenner) in the northeastern United States. Further knowledge of seasonal effects on survival is important for management and modeling of both blacklegged ticks and tick-borne diseases. The focus of our study was on the impact of environmental factors on overwintering success of nymphal blacklegged ticks. In a three-year field study conducted in Connecticut and Maine, we determined that ground-level conditions play an important role in unfed nymphal overwintering survival. Ticks in plots where leaf litter and snow accumulation were unmanipulated had significantly greater survival compared to those where leaf litter was removed (p = 0.045) and where both leaf litter and snow were removed (p = 0.008). Additionally, we determined that the key overwintering predictors for nymphal blacklegged tick survival were the mean and mean minimum temperatures within a year. The findings of this research can be utilized in both small- and large-scale management of blacklegged ticks to potentially reduce the risk and occurrence of tick-borne diseases. Full article
(This article belongs to the Special Issue Tick Surveillance and Tick-borne Diseases)
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