Insects最新文献

Human arboviral diseases such as dengue, chikungunya, and Zika can be transmitted by the mosquito Aedes aegypti. The insecticide-based vector control strategy is critical in reducing transmission of these Aedes-borne diseases but is threatened mainly by the emergence of insecticide resistance. Adult Ae. aegypti from the National Capital Region (NCR), Philippines, were subjected to bioassays to determine their susceptibility to diagnostic doses of pyrethroid, organochlorine, and organophosphate insecticides following the standard World Health Organization insecticide susceptibility test. This study reports the detection of insecticide resistance to pyrethroids and organochlorine in Ae. aegypti from the Philippines for the first time. Most of the Ae. aegypti populations from NCR exhibited phenotypic resistance to permethrin, etofenprox, and DDT. Varying resistance levels to deltamethrin, cyfluthrin, and lambda-cyhalothrin were observed in the different mosquito populations, while all populations tested to malathion were susceptible to this organophosphate. This finding should alert public health authorities to consider modifying the existing vector management package for greater control efficacy. Best practices proven to prevent or delay the development of insecticide resistance, such as insecticide rotation, should also be implemented, while alternative chemicals with a different mode of action should be explored to ensure the continuing efficacy of program interventions.

(1) Background: Ixodes ricinus is responsible for the spreading of medically important pathogens. Monitoring the level of tick infection in various areas is essential for determining the potential tick-born risk. This study aimed to detect Borrelia spp. and Rickettsia spp. in I. ricinus ticks collected in urban and protected areas both in Poland and the Czech Republic. (2) Methods: Ticks were collected by flagging in the years 2016-2017. Borrelia spp. was detected using nested PCR targeting the flaB gene and Rickettsia spp. using nested PCR targeting gltA. (3) Results: In total, DNA of Borrelia spp. was detected in 25.9% of samples. Ticks collected in Poland were more infected compared to the Czech Republic and ticks collected in protected areas were more infected with Borrelia spp. than ticks collected in urban areas. The RFLP analysis showed the occurrence of B. afzelii and B. garinii in both countries, and additionally B. valaisiana, B. burgdorferi s.s., and B. miyamotoi in Poland. Rickettsia spp. was detected in 17.4% of I. ricinus, with comparable infection level in both countries; however, regional differences were observed. (4) Conclusion: The regional differences in Borrelia spp. and Rickettsia spp. prevalence in I. ricinus indicate the complexity of factors influencing the level of infection and underline the need for adaptation public health surveillance strategies in each region.

The cochineal insect Dactylopius coccus Costa (Hemiptera) has cultural and economic value because it produces carminic acid that is used commercially. In this study, distinct fungi were cultured from dissected tissue and identified as Penicillium, Coniochaeta, Arthrinium, Cladosporium, Microascus, Aspergillus, and Periconia. Fungi were microscopically observed inside cochineals in the gut, fat body, and ovaries. Since cochineals spend their lives attached to cactus leaves and use the sap as feed, they can obtain fungi from cacti plants. Indeed, we obtained Penicillium, Aspergillus, and Cladosporium fungi from cacti that were identical to those inside cochineals, supporting their plant origin. Fungi could be responsible for the degrading activities in the insect guts, since cellulase, pectinase, and amylase enzymatic activities in insect guts decreased in fungicide-treated cochineals. Our findings set the basis for the further study of the interactions between insects, fungi, and their host plants.

The Anostostomatidae of Aotearoa New Zealand are well-characterized at the genus and species level, but the higher-level systematics of the family as a whole remain poorly resolved. We tested the hypothesis that the New Zealand anaostostomatid fauna consists of a single monophyletic group consistent with a single common ancestor. For phylogenetic analysis, we sampled the genera in Aotearoa New Zealand as well as representatives of the family from Australia and New Caledonia. Maximum likelihood analyses including topological comparison statistics with a DNA alignment of thirteen mitochondrial and four nuclear protein coding genes rejected the monophyly of lineages in New Zealand. We found phylogenetic support for four separate New Zealand lineages; three with their closest relatives in Australia and one in New Caledonia. The New Zealand genus Hemiandrus is paraphyletic and the establishment of a morphologically distinct genus is justified. We determined that six of the valid species previously placed in Hemiandrus form a distinct clade that we designated here as Anderus gen. nov. The putative Hemiandrus that we sampled from Australia was sister to neither of the New Zealand lineages.

The corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae), is an invasive insect that can cause damage to maize (Zea mays L.) in two ways: by direct feeding and the transmission of several plant pathogens. Dalbulus maidis is an invasive and serious economic pest of maize that has spread from its center of origin in Mexico to the southernmost parts of the United States. Prior to 2024, corn leafhoppers had not been documented in Oklahoma, and their spread northward toward the United States corn belt is of significant concern. Here, we provide the first reports of the insect in maize in several Oklahoma counties. Insect specimens were collected at various commercial and experimental field sites by Oklahoma State University research and extension personnel. The identity of the insect species was validated through morphological and molecular taxonomy. The presence records for the corn leafhopper presented here provide valuable information for future monitoring and management efforts of this economically important pest and disease.

Dengue and other arboviruses remain a global threat, and enhanced efforts to control the mosquitoes that transmit them are urgently needed. A survey of potential manmade Aedes aegypti (L.) and Aedes albopictus (Skuse) oviposition containers was performed in four communities near the end of the typical dry season in 2018 in Trinidad, West Indies. The purpose was to conduct individual premise surveys and use GIS mapping to visualize premises within communities that had Aedes-positive containers, as this information could be used for the prioritization of mosquito control efforts in potential high risk areas as the wet season progressed. Accessible premises were surveyed following standard inspection protocols used by the Insect Vector Control Division (IVCD), Ministry of Health (MOH). The results indicated that two of the four locations would be at high risk for arbovirus transmission going into the wet season. The GIS mapping of premises with Aedes-positive containers facilitated the identification of potential hot spots for arbovirus transmission risk within communities that should be prioritized for enhanced monitoring and vector control efforts, emphasizing the need to increase community participation in standard surveys by IVCD.

Color vision, which varies among species, plays an important role in foraging, mating, and habitat selection among insects. Protaetia brevitarsis (Coleoptera: Scarabaeidae, Lewis) is an omnivorous beetle that damages both crops and fruit. Here, to understand the effect of vision and olfaction in host selection, experiments were conducted on the spectral wavelength preference, color preference, and associative learning ability of adult P. brevitarsis using LED lights and grapes. In our experiments, adults showed the strongest spontaneous preference toward the red spectrum, particularly 730 nm. Non-preferred lights were used to train adults with a food reward (grapes). Green-trained adults had an increasing tendency to prefer green light, and blue-trained adults had a clear preference for blue light. Furthermore, adults significantly preferred red grapes in the absence of olfactory cues, but their selectivity for grapes differed in the presence of olfactory cues, indicating that vision was not the only factor in foraging decisions, but that olfactory cues also influenced their decision making. The results lay the groundwork for revealing their host localization mechanism and provide promising avenues for biological control in the field.

This study has systematically investigated and compared the geographical distribution patterns and population density of G. menyuanensis (Gm) and G. qinghaiensis (Gq), which are endemic to the QTP region and inflict severe damage. Using a method combining the BIOMOD2 integration model (incorporating nine ecological niche models) and current species distribution data, this study has compared changes in potential habitats and distribution centers of these two species during ancient, present, and future climate periods and conducted a correlation test on the prediction results with land use types. The study results indicate that there are differences in geographical distribution patterns, distribution elevations, and population density of these two species. Compared with single models, the integration model exhibits prominent accuracy and stability with higher KAPPA, TSS, and AUC values. The distribution of suitable habitats for these two species is significantly affected by climatic temperature and precipitation. There is a significant difference between the potential habitats of these two species. Gm and Gq are distributed in the northeastern boundary area and the central and eastern areas of the QTP, respectively. The areas of their suitable habitats are significantly and positively correlated with the area of grassland among all land use types of QTP, with no correlations with the areas of other land use types of QTP. The potential habitats of both species during the paleoclimate period were located in the eastern and southeastern boundary areas of the QTP. During the paleoclimate period, their potential habitats expanded towards the Hengduan Mountains (low-latitude regions) in the south compared with their current suitable habitats. With the subsequent temperature rising, their distribution centers shifted towards the northeast (high-latitude) regions, which could validate the hypothesis that the Hengduan Mountains were refuges for these species during the glacial period. In the future, there will be more potential suitable habitats for these two species in the QTP. This study elucidates the ecological factors affecting the current distribution of these grass caterpillars, provides an important reference for designating the prevention and control areas for Gm and Gq, and helps protect the alpine meadow ecosystem in the region.

Since 2015, Scirtothrips dorsalis Hood has emerged as the main pest of strawberries in Florida. Given the limited management options, there is a recognized need to expand on the management strategies for this pest. Therefore, we explored the possibility of using banker plants to recruit naturally occurring predators of thrips into strawberry fields to suppress S. dorsalis. The study began in the 2021-2022 strawberry season where five banker plants were screened to determine which ones could consistently attract thrips predators by flowering throughout the strawberry season. Capsicum annum L. (ornamental pepper) and Lobularia maritima L. (sweet alyssum) were selected for further evaluation. In the 2022-2023 strawberry season, using a randomized complete block design we assessed the capability of these banker plants to attract thrips predators into the strawberry field. In addition, we examined how the banker plant distance from the strawberry plants influenced the S. dorsalis pest suppression. Our results showed that strawberries located within 3.7 m of ornamental pepper plants had less leaf damage from S. dorsalis compared with those farther away, which may result from the repellent effect of the ornamental peppers. Additionally, Geocoris spp. and Orius spp. were identified as the main thrips predators in the system, although in relatively low numbers. Therefore, these results highlight the potential of incorporating ornamental pepper as a banker plant in strawberry production. Additional applications of this research are explored below.

Spodoptera exigua is one of the most serious lepidopteran pests of global importance. With the intensive use of insecticides, S. exigua has evolved resistance to many insecticides, including the sodium channel blocker insecticides (SCBIs) indoxacarb and metaflumizone. In this study, we investigated the role of the V1848I mutation in the voltage-gated sodium channel (VGSC) in SCBI resistance and its inheritance patterns in S. exigua through the development and characterization of a near-isogenic resistant strain. The AQ-23 strain of S. exigua, collected in 2023 from Anqing, Anhui province of China, shows 165-fold resistance to indoxacarb compared with the susceptible WH-S strain. A frequency of 44.6% for the V1848I mutation was detected in the SeVGSC of the AQ-23 strain, while no F1845Y mutation was found. Through repeated backcrossing and marker-assisted selection, the V1848I mutation in the AQ-23 strain was introgressed into the susceptible WH-S strain, creating a near-isogenic strain named WH-1848I. This WH-1848I strain exhibits high levels of resistance to indoxacarb (146-fold) and metaflumizone (431-fold) but remains susceptible to broflanilide and spinosad compared with the WH-S strain. Inheritance analysis revealed that SCBI resistance in the WH-1848I strain is autosomal, nonrecessive, and genetically linked to the V1848I mutation. These findings establish a clear link between the V1848I mutation and SCBI resistance in S. exigua, offering valuable insights for developing molecular detection tools and resistance management strategies.