Project description:The spotted lanternfly, Lycorma delicatula (White, 1845), is an invasive species in the United States. This pest causes damage to vineyards and has the potential to negatively affect other crops and industries. Information describing the seasonal timing of life stages can improve its management. In 2019 and 2020, spotted lanternfly seasonal activity was followed weekly from spring egg hatch to the first hard freeze. Weighted mean timing of activity for each nymphal instar, early adults, late adults, total adults, and egg mass deposition are presented for 2019 and 2020 on Acer rubrum and 2020 on Ailanthus altissima. Logistic equations describing the percentage completion of each activity period on these hosts were fitted using a start date of 1 January to calculate accumulated degree days (ADD). For the adult and egg mass deposition periods, we additionally used a biofix of the date adults were first observed to calculate ADD. ADD from 1 January adequately estimated the timing of nymphal instars but ADD from observation of the first adult better estimated the timing of adult activity and egg mass deposition. Late adult activity and egg mass deposition periods appeared to be influenced by another environmental cue, such as day length. Maps of season-long ADD show that spotted lanternflies are unlikely to reach adulthood in colder regions of the northeast United States, and therefore may not establish there. We also report a strong seasonal trend in sex ratio on A. rubrum, where the population shifted from over 80% male to over 80% female in October.
Project description:Spotted lanternfly (SLF) is an invasive insect in the Northeastern U.S. projected to spread nationally and globally. While SLF is a significant pest of vineyards, little is known about the pest in grape agroecosystems including its spatial ecology. SLF spatial patterns were analyzed using a combination of approaches including generalized linear mixed effect models, Moran's I statistic for spatial clustering, and Empirical Bayesian Kriging. Analysis revealed that SLF displayed significantly clumped distributions in monitored vineyards. Approximately 54% and 44% of the respective adult and egg mass populations were observed within the first 15 m of the vineyard edge. Importantly, the spatial concentration of adults at the edge was consistent temporally, both between years and weeks. Moreover, high populations of SLF on vines were significantly correlated with reduced fruit production in the following year. Mark-release-recapture of SLF revealed that higher proportions of SLF were recaptured on vines with high pre-existing SLF populations, indicating that SLF may exhibit aggregation behavior along vineyard perimeters. Monitoring and management efforts for SLF should be prioritized around vineyard edges as it may significantly reduce infestations and subsequent damage.
Project description:The spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) (White, 1845), is an invasive pest in the Mid-Atlantic region of the United States. Understanding this pest's dispersion patterns is fundamental for development of management and surveillance programs. To address this knowledge gap, we quantified spotted lanternfly nymph dispersion patterns by instar for rural and urban/suburban habitats, and we compared the number of sample units required for sticky traps and in situ visual counts to estimate population densities at several precisions. In addition, we assessed the ability of two experimental designs (completely random and randomized complete block) to detect management practices' impacts in the field. All instars typically followed an aggregated dispersion pattern. Sample size and time requirements for checking and replacing sticky traps and for conducting in situ counts were similar, but in situ counts do not require purchasing traps, installation time, or delays before treatment, and do not remove insects. Although the cost for using in situ counts is likely less than for sticky traps, early instar spotted lanternfly nymph populations are harder to visually detect than later instars because of their small size, which may negate any cost advantage when treatments are applied early. In general, using a randomized complete block design resulted in higher statistical power than a completely random design, allowing detection of proportional population reductions of 10-20% less with equal replication. Studies aiming to evaluate treatments that reduce spotted lanternfly numbers by less than 60% will require researchers to evaluate the feasibility of using the required large sample sizes.
Project description:Lycorma delicatula (White) suddenly arrived in Korea where it rapidly spread out in the central region of Korea and caused serious damage to grape vineyards. To trace the source region of its invasiveness, population genetic structures were compared between the native region, China, and the introduced regions, Korea and Japan. We examined 762 individuals from 38 different population collections using 15 microsatellite loci. Both principal coordinate and structure analyses displayed that the Chinese populations were separated into three subgroups which were located significantly far apart from each other. Among them, the Shanghai population was located closest to most Korean populations. Based on the genetic relationships and structures, it was revealed that the multiple introductions into Korea occurred at least three times. In addition, the Shanghai population was strongly estimated to be a source of initial invasive populations of Korea. In addition, analysis of the approximate Bayesian computation suggested simultaneous spread from two distant locations early in the invasion by artificial transportation of the host plants bearing egg masses. Our population genetics study can provide a precedent case with regards to identifying spreads by anthropogenic outcomes in other invasive regions.
Project description:The spotted lanternfly, Lycorma delicatula White, 1845 (Hemiptera: Fulgoridae), is an invasive pest that attacks forest as well as agricultural trees. We sequenced the 15,798-bp long complete mitochondrial genome (mitogenome) of this species; it consists of a typical set of genes (13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes) and one major non-coding A + T-rich region. The orientation and gene order of the L. delicatula mitogenome are identical to that of the ancestral type found in majority of the insects. Bayesian inference (BI) and maximum-likelihood (ML) phylogeny placed the L. delicatula examined in our study, together with other geographical samples of the species in a group with the highest nodal support, forming the subfamily Aphaeninae to which L. delicatula belongs.
Project description:External structures of insects contribute to the ability of herbivores to select and feed on their host plants. The invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is an economically important and polyphagous insect pest in the eastern US. The lanternfly causes substantial damage to many woody plants by sucking phloem sap, reducing photosynthesis, causing weeping wounds, and creating conditions for sooty mold. Lanternfly nymphs switch host plants during their development. However, little is known about relationship between the lanternfly and its plant hosts, and particularly about morphological adaptations of the lanternfly to host plant usage at each developmental stage of the pest. In this study, we focused on assessing changes in morphology of (a) the lanternfly mouthparts (stylets and labium), and (b) the lanternfly tarsal tips (arolia and tarsal claws) at each developmental stage. Our study revealed several developmental patterns among which the presence of the indentations on mandibular stylets in late instars and adults, as well as the exponential growth of the labium and stylet length, and the tarsal claw dispersal during the lanternfly development. Our findings are critical for investigating and predicting the lanternfly host range, and the lanternfly dispersal to new host trees at each developmental stage.
Project description:Spotted lanternfly (Lycorma delicatula White; SLF) is a phloem-feeding planthopper invasive to the Eastern United States that can feed on a range of wild and cultivated plant species. Since its 2014 introduction in the United States, large infestations and subsequent economic damage have been reported in cultivated grapevines, but no studies have detailed grapevine physiological responses to SLF phloem feeding. This study investigated grapevine-SLF interactions, detailing how different infestation densities affect leaf gas exchange and end-season concentrations of nonstructural carbohydrates and nitrogen in vegetative and perennial tissues of two Vitis species. Effects on fruit ripeness parameters and dormant bud freeze tolerance were examined, in addition to other year-after effects. Phloem feeding by low densities (≤4 SLF shoot-1) had minimal effects, whereas greater densities (5-15 SLF shoot-1) increasingly affected carbohydrate and nitrogen dynamics in both Vitis species. Phloem feeding substantially affected starch and, to a lesser extent, total nitrogen concentrations of woody roots. Prolonged exposure strongly reduced leaf gas exchange. We conclude that intensive late-season phloem feeding by large adult SLF population densities (≥8 SLF shoot-1) can induce carbon limitation, with the potential for negative year-after effects in cases of severe belowground carbon depletion. This work presents novel insights into SLF-grapevine interactions, identifies avenues of future SLF-plant research, and assists the development of action thresholds for SLF management in vineyards.
Project description:The longan lanternfly Pyrops candelaria is a new invasive species on the main island of Taiwan. The introduction of an invasive species may negatively influence the native fauna, flora and environment. Thus, this study aimed to infer the invasion history, predict habitat suitability and potential expansion and assess the risk to crop cultivation areas in Taiwan. Genetic structures of P. candelaria from the main island of Taiwan and related regions were analyzed based on partial COI and ND2 sequences. Additionally, machine learning MaxEnt was utilized to study habitat suitability. The results suggested that the Taiwanese populations may originate from the Kinmen Islands and the plain areas of Taiwan are considered to have high habitat suitability. Furthermore, most of the cultivation areas of longan and pomelo crops showed high habitat suitability.
Project description:The spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), is a generalist phloem feeder that produces copious amounts of honeydew, which in turn coats the understory. These insects form large aggregations covering the trunks of some trees, while similar trees nearby mysteriously seem unattractive. We investigated whether volatiles from SLF honeydew are attractive to conspecifics by collecting honeydew from the field and testing it for SLF attraction in a two-choice olfactometer. We found that honeydew excreted by adult male SLF was significantly attractive to male SLF, but not female SLF. Although the honeydew excreted by adult female SLF did not significantly attract male or female SLF, both sexes showed a positive trend towards attraction in response to female honeydew in the olfactometer. Analysis of the headspace volatiles of honeydew was conducted, and numerous semiochemicals were identified. Five of which, 2-heptanone, 2-octanone, 2-nonanone, benzyl acetate, and 1-nonanol, were tested in two-choice behavioral assays against a blank control. Benzyl acetate and 2-octanone were attractive to both sexes, whereas 2-heptanone was only attractive to males, and 2-nonanone only to females. The remaining compound, 1-nonanol, repelled females, but not males. Although honeydew has been reported as a source of kairomones for some natural enemies, this may be the first report of sex-specific attractants for conspecific insects found in the honeydew volatiles of a planthopper.
Project description:Biological invasion has been a serious global threat due to increasing international trade and population movements. Tracking the source and route of invasive species and evaluating the genetic differences in their native regions have great significance for the effective monitoring and management, and further resolving the invasive mechanism. The spotted lanternfly Lycorma delicatula is native to China and invaded South Korea, Japan, and the United States during the last decade, causing severe damages to the fruits and timber industries. However, its global phylogeographic pattern and invasion history are not clearly understood. We applied high-throughput sequencing to obtain 392 whole mitochondrial genome sequences from four countries to ascertain the origin, dispersal, and invasion history of the spotted lanternfly. Phylogenomic analyses revealed that the spotted lanternfly originated from southwestern China, diverged into six phylogeographic lineages, and experienced northward expansion across the Yangtze River in the late Pleistocene. South Korea populations were derived from multiple invasions from eastern China and Japan with two different genetic sources of northwestern (Loess Plateau) and eastern (East Plain) lineages in China, whereas the each of Japan and the United States had only one. The United States populations originated through single invasive event from South Korea, which served as a bridgehead of invasion. The environmental conditions, especially the distribution of host Ailanthus trees, and adaptability possibly account for the rapid spread of the spotted lanternfly in the native and introduced regions.