Journal of Insect Science最新文献

The eggplant fruit and shoot borer (Leucinodes orbonalis Guenée) is a devastating lepidopteran pest of the eggplant (Solanum melongena L.), causing significant economic losses. Reference genomes aid in understanding insect pest biology and can guide pest management programs. For eggplant fruit and shoot borer, however, genomic resources are scarce; hence, this study presents an annotated genome assembly of the Philippine eggplant fruit and shoot borer genome using Illumina short reads. The 480,399,388 bp long assembly contained 31,568 contigs with an N50 of 204,698 bp and a BUSCO score of 96.5%. Annotation of repeat elements indicates that the eggplant fruit and shoot borer genome comprises 38.50% interspersed repeats, which are mostly unclassified repeats. Functional RNA annotation revealed 1,310 functional RNA genes consisting primarily of tRNAs, rRNAs, snRNAs, and miRNAs. Protein structural annotation predicted a total of 12,671 genes. Annotation using a Cluster of Orthologous groups indicates proteins belonging to group S (unknown), group T (signal transduction), group O (posttranslational modification), and group K (transcription). Of the proteins belonging to group S, PFAM analysis revealed proteins containing chitin, juvenile hormone, odorant and pheromone-binding protein domains, and zinc finger motifs. Further analysis of the predicted proteins indicates that the EFSB possesses conserved biochemical machineries in insect chemosensation, detoxification, and hormone biosynthesis and reception. Variation profiling, on the other hand, detected 11,103,848 SNPs and 3,031,155 indels possibly occurring in Philippine eggplant fruit and shoot borer. Overall, the genome assembly and annotation generated from this study contribute to establishing genome references, and may aid in understanding the EFSB through future studies aimed at its effective control.

Colored sticky traps are used for management of many common agricultural insect pests. Several recent studies have shown that traps can be improved by systematically considering properties of color vision for the target species. In the current study, we extend this approach to spatial vision, using information about the interommatidial angle of an agriculturally important insect pest, western flower thrips Frankliniella occidentalis (Pergande), to predict spatial resolution capabilities for a yellow flower pattern across a range of viewing distances. We tested the hypothesis that pattern sizes matching the spatial resolution capabilities of western flower thrips at a given viewing distance would outperform traps with mismatched pattern sizes by measuring the number of western flower thrips caught on sticky traps containing differently sized flower patterns resolvable at 5, 10, or 20 cm. We found an interaction between pattern size and viewing distance, with significantly more western flower thrips caught on traps when the predicted resolvable distance of the pattern matched the distance traps were placed from a central release point. We further tested the range over which trap patterns are effective in more complex viewing environments using commercial polytunnels. In polytunnel trials, we found that increasing the resolvable distance of patterns increased western flower thrips capture up to approximately 26 cm, after which western flower thrips capture decreased up to the maximal visible range tested (50 cm) in the absence of additional sensory cues. Together, these results show the utility of considering spatial vision in improving trap performance and offers functional insights to improve pest management in visual trap design.

Recently, an unexpectedly large number of large hive beetles, Oplostomus haroldi (Witte), was observed in Taita Taveta County (TTC), Kenya, suggesting a potential threat to the apicultural industry. This study investigated the influence of colony and hive attributes, landscape characteristics, and seasonality on the occurrence of O. haroldi within beehives in TTC. Field surveys assessed beetle populations alongside colony strength parameters, environmental variables, and hive types using standard protocols. Our findings revealed significant positive correlations between beetle occurrence and colony phenotypes, such as capped brood, pollen, and honey quantities. Higher beetle populations were also observed in areas with tree cover compared to cropland, and seasonal variation was evident, with beetle populations peaking during rainy seasons. Langstroth hives exhibited higher infestation levels due to larger entrance areas than Kenya Top-Bar hives and other locally made hive types, which have smaller entrances. These findings suggest that reducing hive entrance sizes with entrance reducers could be an effective management option to limit hive invasion by the beetle, thereby protecting colony health and enhancing productivity in Taita.

The hibiscus mealybug, Nipaecoccus viridis (Newstead) is a phloem-feeding pest that was first documented in Florida citrus orchards in 2019. Feeding causes fruit and leaf deformation due to cellular changes in host plant tissues. Field assays suggest that systemic insecticides can disrupt the probing behavior of this phloem feeder. However, the mechanisms involved are poorly understood. The objective of this study was to investigate the feeding interactions of second-third instar N. viridis on Volkamer lemon trees (Citrus volkameriana) using AC-DC Electropenetrography. Since preliminary recordings failed to distinguish phloem salivation from phloem ingestion waveforms, the effects of 3 tethering materials to improve waveform resolution were tested: thick gold wire (25 µm diameter), fine gold wire (12.5 µm diameter), and Wollaston platinum wire (2.5 µm diameter). In addition, a combination of 3 different input resistances (Ri) (amplifier sensitivities) and substrate voltages; 109 Ω with 250 mV; 1010 Ω with 100 mV; and 1013 Ω with 0 mV were compared to create a waveform library. The best-quality signal was obtained with the thick gold wire (25 µm diameter) at Ri 1010 Ω using the loop method of wiring. Wollaston platinum wire impeded nymphal movement, causing increased nonprobing duration and increased time from the start of the recording to the first phloem salivation. Biological interpretations of waveforms are discussed in light of fruit and leaf distortion. Results from this study will allow future work to compare effectiveness of insecticides to prevent such damage.

The Indianmeal moth, Plodia interpunctella (Hübner) is a major polyphagous pest of stored food products causing serious quantity and quality losses. In this study, the life history of P. interpunctella was evaluated on different maize varieties, including Simon, Valbom, 703, BK, and BC678. The preadult duration for P. interpunctella were 35.5, 43.1, 39.2, 43.4, and 36.8 d on Simon, Valbom, 703, BK, and BC678, respectively. The mean total longevity on Valbom was 52.2 d which was significantly longer than the 41.8 d on Simon (P = 0.012). The developmental period of moths was the most prolonged on Valbom indicating low nutritional suitability of this variety. However, the moths preferred Valbom for oviposition, and more than 132 eggs were laid on this variety. The most intrinsic rate of increase (r) was reported on BC678 and Simon, while the lowest population growth rate was on BK and Valbom. The highest r value on BC678 and Simon could be due to their high moisture and protein content. Based on the shorter preadult, total preoviposition period, mean generation time and higher life table parameters (gross reproductive rate, r, and λ) that occurred on the BC678, make this variety most favorable host for P. interpunctella. The findings highlighted the importance of maize variety selection in managing this pest in stored food products.

Insect herbivores often experience seasonal fluctuation in food availability, which plays important role in signaling diapause and/or migration. However, the introduction of non-native plants with different seasonal phenologies has the potential to disrupt these dynamics. Some evidence suggests that this may be a developing issue for the annual migration of the monarch butterfly Danaus plexippus (Linnaeus) (Lepidoptera: Nymphalidae). The tropical milkweed Asclepias curassavica (Linnaeus) (Gentianales: Apocynaceae), which does not seasonally senesce to the same extent or rate as native milkweed host plants, has recently been introduced into the North American mainland population. Here, we report an experimental comparison of monarch developmental success when reared on A. curassavica and the native A. incarnata (Linnaeus) (Gentianales: Apocynaceae) in the summer and fall. We found that A. curassavica facilitates monarch development later into their typical migratory and over-wintering season, despite several prolonged periods where the temperature was below requirements for growth and development.

Natural host-plant resistance provides a sustainable solution to control insect outbreaks but can be limited due to insect counter-adaptation. The exact mechanisms of insect adaptation to host-plant resistance remain unclear in most systems. Some insect adaptations are controlled by epigenetic mechanisms, such as through noncoding RNA. PIWI-interacting RNAs are specific noncoding RNAs that bind with PIWI proteins to control a diverse range of gene regulatory functions, particularly in insects. Previous investigation into aphid PIWI gene copies showed expansion in their abundance compared to other insects, which may suggest PIWI genes have additional functions among aphids. We first characterized PIWI gene evolution through a phylogenetic analysis, then investigated the role of PIWIs by examining gene expression in the soybean aphid (Aphis glycines), a significant insect pest of soybean which has adapted to overcome aphid-resistance in host plants. Our data indicated the presence of three PIWI ortholog groups, as well as taxon-specific gene expansions, with gene copy numbers ranging from 3 to 17 across species. To evaluate a potential role of PIWIs in overcoming host-plant resistance, we measured their gene expression in Ap. glycines with (virulent) and without (avirulent) the ability to survive on aphid-resistant soybean. We found that virulent Ap. glycines have significantly higher expression of 2 PIWI genes (Agl1.1 and Agl1.3) compared to the avirulent biotype. These data suggest that gene regulatory mechanisms related to the PIWI pathway, potentially including piRNAs, are important in aphid systems and may enable adaptation to host-plant resistance.

The cotton aphid, Aphis gossypii Glover, is an important plant disease vector and a highly polyphagous agricultural pest that feeds on a broad range of host plants. During feeding, its salivary glands serve as a route for the transmission of circulative plant viruses and produce a range of secretory proteins, called effectors, to modulate host cellular processes. To understand the molecular mechanisms underlying aphid-plant interactions, we developed a bioinformatics pipeline that incorporated the salivary gland transcriptome, genome, and head vs abdomen differential gene expression data to predict secretory protein-encoding genes enriched in the salivary glands of A. gossypii. Annotation of the 351 predicted genes showed that the most abundant functional categories were associated with cellular signaling and metabolism processes, and revealed that 98 genes were hemipteran-specific. Notably, 51 genes encode secretory proteins matching the putative saliva proteins identified in prior proteomics studies. Quantitative PCR analysis validated differential expression of 4 selected genes between heads and abdomens and indicated that alate adults exhibited the highest gene expression, suggesting these genes may play key roles in host colonization. Additionally, 25 genes showed sequence similarities to functionally characterized hemipteran effectors, with some appearing to form effector groups with distinct evolutionary patterns. Collectively, this study identified numerous putative plant-manipulating genes in A. gossypii and provided valuable insights into the mechanisms of aphid-plant interactions.

Honey bees (Apis mellifera L.) are of undeniable value to agriculture. However, increased mortality of honey bees, mostly due to winter losses associated with parasites and pathogens, have put strain on the apiculture industry. Advancing our knowledge of honey bee viruses and their interactions within the colony environment is vital in mitigating their effect on honey bee health. Our study examined virus sequences detected on beeswax sampled from empty colonies which died during the previous winter. Based on a cage study using virus-containing bees, we confirmed that the introduction of BQCV sequences to wax foundation was possible through workers walking on, and contacting, comb surfaces (worker traffic). Furthermore, we found that BQCV may aerosolize within an incubator to contaminate wax at detectable levels among independent cages. A second cage study explored the potential effects of virus aerosolization on transmission between groups of adult worker bees within cages, having no direct contact. This experiment did not support aerosol transmission between groups of bees in confined spaces. Further work on waxborne virus transmission within colony environments, and potential effects of aerosolization under a wider array of conditions, is crucial to broadening our knowledge of honey bee virus transmission. Our work also highlights potential dangers for beekeepers re-using equipment from dead colonies.

Identifying a DNA extraction method that yields high quantity and quality DNA is a crucial component of molecular ecological studies; and the best suited method can vary greatly depending on research priorities. Here, we propose a nondestructive extraction method for insect museum vouchers aimed at analyzing gut-associated microbiomes. The leafhopper Euscelidius variegatus (Kirschbaum) (Hemiptera: Cicadellidae) associated with the bacterial plant pathogen Flavescence dorée phytoplasma, a member of the genus 'Candidatus Phytoplasma' (Mollicutes: Acholeplasmataceae), was used as an experimental model. We developed and refined a resin-based DNA extraction protocol by testing the effects of prelysis bleaching and postlysis proteinase K inactivation on DNA quality and yield. We found that bleaching did not compromise the integrity of insect and associated bacterial DNA and that excluding the inactivation of proteinase K did not interfere with quantitative polymerase chain reaction analysis. Based on our findings, we recommend a DNA extraction protocol for insect voucher specimens and associated microbiomes that includes a prelysis bleaching step to chemically degrade external contaminants without proteinase K inactivation, thereby reducing processing time. Our refined protocol resulted in a high DNA yield, which we successfully analyzed using quantitative polymerase chain reaction analysis and other downstream molecular applications, including targeted high-throughput sequencing.