Defense sequestration associated with narrowing of diet and ontogenetic change to aposematic colours in the spotted lanternfly

Spotted Lanternflies Respond to Natural Pheromone Lures for Mate-Finding and Oviposition

Using semiochemicals collected from spotted lanternflies Lycorma delicatula (Hemiptera: Fulgoridae) (SLF) and deployed in the field with circle traps, we demonstrated that SLF responded to SLF pheromones: in particular, this was the case for males while seeking mates and for females while ovipositing. The attractants consisted of SLF body extract emitted from diffuser lures and SLF honeydew on burlap ribbons, collected from heavily infested locations. Traps with attractants were deployed in field sites with very light SLF infestations to avoid competing signals of pre-existing aggregations. The number of SLF equivalents emitted by each diffuser per trapping period was used in a dose-response analysis. Three trees per block received either (1) a control hexane lure and a clean ribbon, (2) a lure containing SLF extract and a clean ribbon, or (3) a lure containing SLF extract and a honeydew-laden ribbon. Ten blocks were sampled three times per week for twelve weeks. We found a significant positive dose-response by males to SLF body extract only in the presence of SLF honeydew, indicating a synergistic effect between honeydew volatiles and body volatiles. This dose-response occurred for five weeks after mating started, after which males no longer responded. Subsequently, females had a significant positive dose-response to SLF extract only in the presence of honeydew when oviposition was their primary activity, continuing for two weeks, suggesting that females may use pheromones to aggregate for oviposition. The extract in the absence of honeydew did not result in a positive dose-response, nor did the hexane control. These findings suggest that SLF respond synergistically to the combination of pheromones present in both SLF honeydew and SLF bodies. Thus, combining key components from both sources may aid the development of semiochemical lures for SLF.

Hypoxia and its effect on the cellular system

Eukaryotic cells utilize oxygen for different functions of cell organelles owing to cellular survival. A balanced oxygen homeostasis is an essential requirement to maintain the regulation of normal cellular systems. Any changes in the oxygen level are stressful and can alter the expression of different homeostasis regulatory genes and proteins. Lack of oxygen or hypoxia results in oxidative stress and formation of hypoxia inducible factors (HIF) and reactive oxygen species (ROS). Substantial cellular damages due to hypoxia have been reported to play a major role in various pathological conditions. There are different studies which demonstrated that the functions of cellular system are disrupted by hypoxia. Currently, study on cellular effects following hypoxia is an important field of research as it not only helps to decipher different signaling pathway modulation, but also helps to explore novel therapeutic strategies. On the basis of the beneficial effect of hypoxia preconditioning of cellular organelles, many therapeutic investigations are ongoing as a promising disease management strategy in near future. Hence, the present review discusses about the effects of hypoxia on different cellular organelles, mechanisms and their involvement in the progression of different diseases.

Modelling the emergence of social-bird biological controls to mitigate invasions of the spotted lanternfly and similar invasive pests

The spotted lanternfly is an emerging global invasive insect pest. Due to a lack of natural enemies where it is invasive, human intervention is required. Extensive management has been applied but the spread continues. Recently, the idea of bird-based biological controls has re-emerged and shown effective in studies. However, it is questionable, if birds are able to effectively control unfamiliar and occasionally toxic invasive pests in short timeframes. Unless, perhaps, the birds are effective social learners and toxicity of the invaders is rare. Here, we introduce a mathematical model for social learning in a great tit-like bird to investigate conditions for the emergence of a collective biological control of a pest that is occasionally toxic, like the lanternfly. We find that the social observation rate relative to the proportion of toxic lanternfly dictate when collective biological controls will emerge. We also implement the social learning model into a model of collective motion in bird-like animals, and find that it produces results consistent with the mathematical model. Our work suggests that social birds may be useful in managing the spotted lanternfly, and that removing the toxicity-inducing preferred host of the lanternfly should be a priority to facilitate this.

Using community science to identify predators of spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), in North America

Spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an invasive insect that was first detected in the United States in 2014 and feeds on a wide variety of plants, with economic impacts on the agricultural, ornamental, and timber industries. Part of what likely contributes to the success of L. delicatula in its invaded range is that it appears to be chemically defended by sequestering toxins from its host plant(s), which may deter predators in the introduced range. To determine the identity and behavior of North American predators that feed on spotted lanternfly, we performed a community science study in which we asked members of the public to contribute reports of animals feeding on spotted lanternfly through a Facebook page. The largest group of reported predators was arthropods followed by birds. Araneae was the arthropod order with the most reports and Phasianidae was the most frequently reported bird family. Using Pearson's χ2 tests, we also identified significant relationships between predator behavior and (1) taxonomic group of the predator, (2) L. delicatula life stage, and (3) host plant L. delicatula was observed on. These results can help to guide future research on predator host shifting to spotted lanternfly and potential for biocontrol as a management tactic.

Factors Guiding the Orientation of Nymphal Spotted Lanternfly, Lycorma delicatula

A mark-release-recapture experiment was conducted to evaluate the orientation of spotted lanternfly (SLF) Lycorma delicatula White (Hemiptera: Fulgoridae) nymphs when released equidistant between two trees. The experiment was repeated weekly for eight weeks in a heavily infested area with mature tree-of-heaven Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae) planted in rows as ornamental street trees in Beijing, China. One tree in each pair received a methyl salicylate lure, and the lure was rotated between trees every week as it aged. Two additional independent variables for each tree were also analyzed: size and SLF population density. Marked-released SLF significantly chose trees with higher SLF population density over trees with lower density populations, and they also chose larger trees significantly more than smaller trees. Population density and tree size were better predictors of attraction than lures, but when those factors were controlled, SLF significantly chose trees with methyl salicylate lures over control trees for the first 4 weeks of lure life. Wild SLF distribution was assessed weekly, revealing strong aggregation in first and second instars that diminished with development to the third and fourth instars. Thus, nymphal SLF aggregate, and orientation is strongly guided by the presence of other SLF and tree size.

Macroevolution of protective coloration across caterpillars reflects relationships with host plants

A critical function of animal coloration is avoiding attack, either by warning predators or reducing detectability. Evolution of these divergent strategies may depend on prey palatability and apparency to predators: conspicuous coloration may be favoured if species are distasteful, or habitats make hiding difficult; by contrast, camouflage may be effective if prey lack defences or environments are visually complex. For insect herbivores, host plants provide both chemical defence and the background against which they are detected or obscured; thus, plant traits may be key to coloration in these foundational terrestrial organisms. We use 1808 species of larval Lepidoptera to explore macroevolution of protective coloration strategy. We find that colour and pattern evolve jointly in caterpillars, similar to an array of species across the animal kingdom, while individual elements of coloration evolve closely with diet ecology. Consistent with key tenets of plant defence and plant-herbivore coevolutionary theory, conspicuous colours are associated with herbaceous host plants-thought to be defended by toxins-while camouflage colours and patterns are associated with woody plants and grasses. Contrary to theory, dietary specialization is not associated with conspicuous coloration. Our results add valuable insights into the evolutionary forces shaping colour and pattern in nature.

The impact of host plant species on instar duration and body weight of nymphal Lycorma delicatula

The spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), is an invasive species of planthopper that was introduced to North America and is a threat to multiple industries. Nymphs and egg masses were collected to assess each instar's rate of development at a constant temperature of 25°C on the following hosts: Ailanthus altissima (Miller) (Sapindales: Simaroubaceae), Vitis labrusca (L.) (Vitales: Vitaceae), Salix babylonica (L.) (Malpighiales: Salicaceae), Acer rubrum (L.) (Sapindales: Sapindaceae), Celastrus orbiculata (Thunberg) (Celastrales: Celastraceae), Ocimum basilicum (L.) (Lamiales: Lamiaceae), and Rosa multiflora (Thunberg) (Rosales: Rosaceae). Host plant species was found to have a significant effect on developmental time for nymphs in the first through third instars, as well as on nymphal survival. Nymphs failed to develop through the second instar on O. basilicum and the third and fourth instars on A. rubrum. Host plant species also had a significant effect on the mean weight of nymphs in the first, second, and fourth instars (but not in the third instar), and on the hind tibia length and forewing width of adult nymphs. This variability in L. delicatula developmental time by host plant species can potentially impact phenology models, which should be updated to reflect these new insights. Rearing practices should also be refined to account for host plant influences on the physiology of L. delicatula.

Volatiles from male honeydew excretions attract conspecific male spotted lanternflies, Lycorma delicatula (Hemiptera: Fulgoridae)

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.

Responses of adult spotted lanternflies to artificial aggregations composed of all males or females

Spotted lanternflies (SLF) Lycorma delicatula are economically important invasive planthoppers discovered in North America in 2014. SLF are gregarious, but how they locate each other, or who finds whom and when, is poorly understood. Here we describe adult SLF behavior and phenology on their preferred host, Ailanthus altissima, under field conditions, in the context of both aggregation and mate-location, since SLF demonstrated aggregation prior to mating. We documented aggregation behavior of adults and found we could manipulate free-living SLF populations in both number and sex ratio by the placement of confined populations of SLF males or females on trees. Trap capture of arriving SLF was significantly higher on trees with confined SLF aggregations than on control trees, and was corroborated with photographic data, demonstrating the manipulation of attraction and aggregation behavior. Sex ratios of trapped SLF arrivals were significantly more male-biased on trees with confined males and more female-biased on trees with confined females, evidence that the male- and female-biased sex ratios observed on trees naturally can be explained by sex-specific conspecific signals. SLF sex ratios shifted over time in the same pattern over two consecutive years. A mark-release-recapture study over time found that 1) SLF behavior is density dependent and strongly influenced by natural populations, 2) released females were captured significantly more on trees with caged females, particularly prior to mating, and 3) released males were captured significantly more on trees with caged females starting at mating time. Photographic data revealed that most clustering behavior (a measure of courtship) of free-living SLF began on trees with caged females during mating time, but not on trees with caged males or controls. We describe adult male and female SLF phenology whereby 1) aggregation behavior occurs, 2) males and females arrive at different times, 3) females began to aggregate several weeks prior to mating, 4) males subsequently joined aggregations at the time of mating, and 5) aggregation continued into oviposition. Population density and aggregation behavior were found to be key factors in their natural history which can be manipulated, providing a foothold for future research. Possible mechanisms for future exploration are discussed.

Oviposition selection in spotted lanternfly: impact of habitat and substrate on egg mass size and hatchability

Oviposition strategies adopted by insects (e.g., habitat selection, substrate preference, egg size, clutch size, structure, arrangement, parental care) are critical to the survival and development of their eggs. The impact of habitat and oviposition substrate on spotted lanternfly egg mass size and hatchability was studied in Pennsylvania through laboratory observations and field monitoring in 2019 and 2021. Eggs were arranged in single layers of 1-13 columns (1-18 eggs/column) on surfaces of various types of oviposition substrates, with the longest column(s) in the middle of the egg mass. Egg mass size was positively correlated with column number, with a mean of 26.6-35.1 (0-105) eggs/egg mass for different samples. Significant differences in egg mass size were observed between study sites, with larger egg masses found at Wertz (44.8), Sam Lewis (40.6), Pinnacle (39.1), Marsh Creek (37.9), Susquehannock (34.5), and Memorial Lake (33.3) and smaller egg masses at Nolde Forest (25.0), Gordon (24.4), and Antietam (21.0). Significant differences were also detected between types of oviposition substrates with smaller egg masses found on American hornbeam (22.7). In general, more (31.6%-48.0%) eggs hatched in the field compared with the laboratory (10.0%). Egg hatch success was positively correlated with egg mass size, with the highest rates recorded on American beech, American hophornbeam, black birch, black cherry, black locust, hackberry, Norway maple, red maple, and sweet cherry at Wertz, Marsh Creek, Memorial Lake, and Pinnacle. Potential (positive or negative) impacts of tree-of-heaven density, initial infestation, treatment history, and incubation conditions are discussed.

Diverse Host Plants of the First Instars of the Invasive Lycorma delicatula: Insights from eDNA Metabarcoding

Identification of host plants of the invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), has been the focus of many studies. While the adults and late nymphs are relatively easy to observe on plants and to use for molecular gut-content analysis, studying the early instars is more challenging. This study is the continuation of our ongoing efforts to determine the host range for each developmental stage of L. delicatula. In the present study, we focused exclusively on the first nymphal instars, and we used a novel approach, utilizing "bulk" DNA extracts for DNA metabarcoding of nymphal gut contents, to identify all the detectable plants that the nymphs had ingested prior to being collected. We were able to obtain high-quality amplicons (up to 406 bp) of a portion of the rbcL gene and detect 27 unique ingested plant species belonging to 17 families. Both native and introduced plants with the prevalence of trees and grasses were present among the ingested plants. We also identified 13 novel host plants that have not been previously reported for L. delicatula on the U.S. territory. The results from our study have important applications for developing effective programs on early monitoring of invasive L. delicatula.

Spotted lanternfly predicted to establish in California by 2033 without preventative management

Models that are both spatially and temporally dynamic are needed to forecast where and when non-native pests and pathogens are likely to spread, to provide advance information for natural resource managers. The potential US range of the invasive spotted lanternfly (SLF, Lycorma delicatula) has been modeled, but until now, when it could reach the West Coast’s multi-billion-dollar fruit industry has been unknown. We used process-based modeling to forecast the spread of SLF assuming no treatments to control populations occur. We found that SLF has a low probability of first reaching the grape-producing counties of California by 2027 and a high probability by 2033. Our study demonstrates the importance of spatio-temporal modeling for predicting the spread of invasive species to serve as an early alert for growers and other decision makers to prepare for impending risks of SLF invasion. It also provides a baseline for comparing future control options.

Process-based modelling reveals the predicted spread of the invasive spotted lanternfly to California by 2033 without controlled management.

Survivorship and Development of the Invasive Lycorma delicatula (Hemiptera: Fulgoridae) on Wild and Cultivated Temperate Host Plants

The invasive spotted lanternfly, Lycorma delicatula, (White Hemiptera: Fulgoridae) continues to spread throughout the Eastern United States. This species exhibits a broad host range, with tree of heaven, Ailanthus altissima (Mill.) Swingle, commonly referred to as the preferred host. Here, we evaluated 2-wk survivorship of early nymphal instars, late nymphal instars, and adult L. delicatula on single diets of ten wild and cultivated hosts: tree of heaven; apple, Malus domestica; peach, Prunus persica; black cherry, P. serotina Ehrh; black locust, Robinia pseudoacacia L.; black walnut, Juglans nigra L.; common hackberry Celtis occidentalis L.; mulberry Morus alba L.; sugar maple Acer saccharum Marshall; white oak, Quercus alba L.. Among them, early and late instars had significantly greater survivorship on tree of heaven and black walnut and adults had greatest survivorship on tree of heaven. Additionally, we evaluated development and survivorship of L. delicatula from newly hatched nymphs to adulthood on single diets of tree of heaven, black walnut, grapevine, apple, and peach, and mixed diets of tree of heaven plus one other host. Single host diets that supported L. delicatula development to adulthood were tree of heaven and black walnut. Interestingly, mixed diets also supported development, and reduced development time to adults by up to 12% compared with the single tree of heaven diet. Our results suggest that within agroecosystems and across landscapes, L. delicatula can develop on single hosts such as tree of heaven, but also on multiple host plants, yielding adults earlier in the growing season.

Uric acid, as a double-edged sword, affects the activity of epidermal growth factor (EGF) on human umbilical vein endothelial cells by regulating aging process

Uric acid (UA) is the main metabolite of the human body. Although UA is only a product of metabolism, it is important biological regulator. Epidermal growth factor (EGF) has important biological functions. However, so far, the effect of UA on EGF’s activity has not been revealed. For this, in the current study, we systematically studied the effect of OA on the biological activity of EGF. Human Umbilical Vein Endothelial Cells (HUVECs) were used as an in vitro model, and Western-blot, RT-PCR, laser scanning confocal microscopy (CLSM) and co-localization analyses were carried out. The results showed that high concentration of UA (10 mg/dl) severely affected the biological activity of EGF. High concentration of UA suppressed the activity of EGF, and inhibited the biological effect of EGF on the HUVECs. However, it is interesting that EGF-mediated intracellular signaling was significantly down-regulated in the H₂O₂-induced senescent HUVEC, and physiological concentration of UA could at least partially restore the EGF-mediated signaling. Further work showed that physiological concentration of UA (5 mg/dl) shows the anti-aging effect. Taken together, current research indicates that UA may be a ‘double-edged sword’, physiological concentration of UA may be beneficial, but high concentrations of uric acid (UA) are harmful.

Sequestration of Plant Defense Compounds by Insects: From Mechanisms to Insect-Plant Coevolution

Plant defense compounds play a key role in the evolution of insect-plant associations by selecting for behavioral, morphological, and physiological insect adaptations. Sequestration, the ability of herbivorous insects to accumulate plant defense compounds to gain a fitness advantage, represents a complex syndrome of adaptations that has evolved in all major lineages of herbivorous insects and involves various classes of plant defense compounds. In this article, we review progress in understanding how insects selectively accumulate plant defense metabolites and how the evolution of specific resistance mechanisms to these defense compounds enables sequestration. These mechanistic considerations are further integrated into the concept of insect-plant coevolution. Comparative genome and transcriptome analyses, combined with approaches based on analytical chemistry that are centered in phylogenetic frameworks, will help to reveal adaptations underlying the sequestration syndrome, which is essential to understanding the influence of sequestration on insect-plant coevolution.

Phenology of Lycorma delicatula (Hemiptera: Fulgoridae) in Virginia, USA

The spotted lanternfly, Lycorma delicatula (White), is an invasive planthopper that was first discovered in North America in Berks County, Pennsylvania in 2014. Currently, L. delicatula has spread to eight additional states and threatens agricultural, ornamental, and timber commodities throughout the United States. The timing of insect life events is very important in the development of pest management tools and strategies. In 2019 and 2020, L. delicatula phenology was successfully documented in Winchester, Virginia using weekly 5-min observational surveys at established monitoring plots. Each year, L. delicatula were active in the environment from May to November with initial detections of first, second, third, fourth, and adults occurring in May, May, June, June, and July, respectively. Cumulative average growing degree days were also calculated for the onset of each L. delicatula life stage using local weather data and a lower developmental threshold of 10°C. First-instar L. delicatula were initially observed at 135 and 111.5, adults at 835 and 887, and egg masses at 1673.5 and 1611.5 in 2019 and 2020, respectively. Combined, these data can be used by growers and land managers to facilitate timing of effective pest management strategies.

Performance and host association of spotted lanternfly (Lycorma delicatula) among common woody ornamentals

Lycorma delicatula (spotted lanternfly) has a broad host range with a strong preference for the invasive host plant from its native range, tree of heaven (Ailanthus altissima); it had long been speculated that L. delicatula could not develop or reproduce without access to tree of heaven. In 2019, we found that this assumption was incorrect, but fitness was reduced in the absence of A. altissima in that the number of egg masses laid was dramatically fewer for insects reared on suitable non-A. altissima host plants that had recently been established. We hypothesized that longer established, larger trees (of the same species) would improve the fitness of L. delicatula in the absence of tree of heaven. In spring 2020, we examined insect performance with and without access to A. altissima by tracking development, survival, host tree association and oviposition in large enclosures with trees planted two years prior to the study. Each enclosure included one each of Juglans nigra, Salix babylonica and Acer saccharinum along with either one A. altissima or one Betula nigra; these trees had twice the diameter of the same trees the previous year. We reared nymphs with and without access to A. altissima, released them into the corresponding large enclosures as third instars, and monitored them from early July 2020 through November 2020. We also determined whether lack of access to A. altissima by parents of L. delicatula have any fitness effects on offspring performance. To ensure adequate adult populations for comparing fecundity between treatments, third instars were released into the multi-tree enclosures due to high mortality in earlier instars that occurred in a similar study in 2019. Insect survival was higher and development faster with access to A. altissima. Third and fourth instar nymphs were most frequently observed on A. altissima when it was present, while adults were equally associated with A. saccharinum and A. altissima. In the absence of A. altissima, nymphs were most frequently found on S. babylonica, while adults were most often on A. saccharinum. Females with access to A. altissima deposited nearly 7-fold more egg masses than those without access to A. altissima, which is consistent with the difference in egg mass numbers between the two treatments the previous year; thus, our hypothesis was rejected. The offspring of parents that had been reared without access to A. altissima showed similar survival and development time from egg to adult as offspring from parents that never had access to A. altissima. These findings suggest that managers need to be aware that even in the absence of A. altissima in the landscape, several hardwood host trees can be utilized by L. delicatula to develop and reproduce, but fitness without A. altissima is likely to still be reduced.

Lactobacillus acidophilus ATCC 4356 Exopolysaccharides Suppresses Mediators of Inflammation through the Inhibition of TLR2/STAT-3/P38-MAPK Pathway in DEN-Induced Hepatocarcinogenesis in Rats

Probiotics have been suggested as a safe and cost-effective approach to prevent or treat hepatocellular carcinoma (HCC). Some of the exopolysaccharides (EPSs) produced by lactic acid bacteria confer health benefits such as immunomodulatory and antitumor activities. The present study was therefore aimed to investigate the immunomodulatory effect of Lactobacillus acidophilus ATCC 4356 EPSs against diethylnitrosamine (DEN) and gamma radiation (IR) induced HCC either as prevention or treatment in male rats' model. Biochemical results revealed a significant increase in serum ALT and γ-GT activities as well as MDA, IL-17, TGF-β1, signal transducer and activator of transcription-3 protein (STAT3), mitogen-activated protein kinase p38 (p38MAPK) levels in the liver tissue. The gene expression level of the liver toll-like receptor 2 (TLR-2) gene was also increased. However, prevention and treatment with EPSs ameliorated most of the investigated parameters. The histopathological observations of liver tissues were in agreement with restored biochemical results. In conclusion, Lactobacillus acidophilus ATCC 4356 EPSs are efficacious control against HCC throughout the regulation of TLR2/STAT-3/P38-MAPK Pathway associated with inflammation. Therefore, our novel EPSs ATCC 4356 could be used as a good, safe and effective probiotic to prevent hepatocarcinogenesis in suspected patients.

Distribution, Survival, and Development of Spotted Lanternfly on Host Plants Found in North America

Studies were conducted from 2015 to 2018 to evaluate spotted lanternfly (SLF) distribution and developmental suitability of different plant species in the U.S. Tree bands on 283 trees spanning 33 species captured 21,006 SLF in 2 yr. More SLF per tree were trapped on tree-of-heaven Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae) than on other species, on average, and most adults were captured on tree-of-heaven. Frequency of detection of adult SLF was higher on tree-of-heaven than on other species but was actually equal or lower on tree-of-heaven than on all other species combined for younger SLF stages in 2015. An enclosed choice test between tree-of-heaven and black walnut Juglans nigra L. (Fagales: Juglandaceae) revealed nymphs showed little consistent preference, whereas adults consistently and significantly preferred tree-of-heaven. No-choice field sleeve studies evaluated SLF survivorship on 26 host plant species in 17 families. Ten plant species supported SLF for an average of ≥45 d, with the rest unable to support SLF for >30 d. Eight species were able to support development from first instar to adult: black walnut, chinaberry Melia azedarach L. (Sapindales: Meliaceae), oriental bittersweet Celastrus orbiculatus Thunb. (Celastrales: Celastraceae), tree-of-heaven, hops Humulus lupulus L. (Rosales: Cannabaceae), sawtooth oak Quercus acutissima Carruthers (Fagales: Fagaceae), butternut Juglans cinerea L, and tulip tree Liriodendron tulipifiera L. (Magnoliales: Magnoliaceae). The ability of SLF to develop to adult on hosts other than tree-of-heaven may impact pest management decisions.

Spotted Lanternfly (Hemiptera: Fulgoridae) Can Complete Development and Reproduce Without Access to the Preferred Host, Ailanthus altissima

Despite its broad host range, the spotted lanternfly Lycorma delicatula (White), is known to have a marked preference for Ailanthus altissima. However, whether this polyphagous phloem feeder can complete its life cycle in the absence of A. altissima is unknown. We examined the performance of L. delicatula with and without access to A. altissima by tracking development, survival, host tree species association, and oviposition in large enclosures planted with Salix babylonica and Acer saccharinum along with either A. altissima or Betula nigra. We monitored enclosures from late May 2019 through June 2020. Lycorma delicatula survival was slightly higher in enclosures with A. altissima and 50% of individuals in A. altissima enclosures reached the adult stage ~6.5 d earlier than in enclosures without A. altissima. In the presence of A. altissima, nymphs were most frequently observed on this host while adults were found at similar frequencies on A. altissima and A. saccharinum. In the absence of A. altissima, nymphs were most frequently associated with S. babylonica and A. saccharinum, while adults were most often found on A. saccharinum. Females laid a total of 46 and 6 egg masses in enclosures with and without A. altissima, respectively, before freezing temperatures killed the remaining adults. The proportion of eggs that hatched per egg mass did not differ between treatments. Although L. delicatula can complete development and reproduce on other host species without access to A. altissima, fitness was reduced. These findings have implications for management that relies exclusively on treatment of A. altissima.

Worldwide Feeding Host Plants of Spotted Lanternfly, With Significant Additions From North America

The spotted lanternfly Lycorma delicatula (White) is an invasive insect spreading throughout southeast Asia and eastern North America. The rapid spread of this species is facilitated by the prevalence of its preferred host, tree of heaven (Ailanthus altissima (Mill.) Swingle), as well as its use of many other host plants. While the spotted lanternfly has been previously reported to use over 65 plant species, most of these reports are from Asia and may not be applicable in North America. Additionally, many of the known hosts have not been specified as feeding hosts or as egg laying substrates. To better understand the potential impacts of this invasive insect on natural and cultivated systems in North America, we reviewed records from published and unpublished results and observations of host plant use by spotted lanternfly. We aggregated 172 host plant records worldwide and found feeding behaviors associated with 103 plant taxa across 33 families and 17 orders, 20 of which were not previously known to be associated with SLF and 15 of which were not confirmed as feeding hosts. North American records account for 56 of these taxa which include native, cultivated, and nonnative species. As a result, the spotted lanternfly has the potential to impact a wide assortment of ecosystems throughout its potential range and its North American distribution may not be limited by the presence of tree of heaven.

Plant Volatiles Help Mediate Host Plant Selection and Attraction of the Spotted Lanternfly (Hemiptera: Fulgoridae): a Generalist With a Preferred Host

Host plant volatiles play a key role in mediating plant-herbivore interactions. How an array of host plant volatiles guides host preference and attraction in the invasive polyphagous Lycorma delicatula (White), the spotted lanternfly (SLF), is largely unknown. A pernicious phloem feeder, SLF feeds on over 70 species of plants, some with high economic impact. To aid the development of detection and monitoring tools for SLF, we used a two-choice olfactometer to compare 14 host plant species for attraction, first to a blank control, and then to their preferred host Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), tree-of-heaven. SLF were significantly attracted to seven host plants compared to a blank control, but no host plant was more attractive than tree-of-heaven. We then used electroantennographic detection (EAD) to screen select host plants for EAD active compounds, hypothesizing that EAD-active plant volatiles act as kairomones and mediate SLF attraction to host plants. Out of 43 unique antennal responses, 18 compounds were identified and tested individually for attraction in a two-choice olfactometer against a blank control and then against methyl salicylate, the current best attractant. Eleven compounds were significantly attractive, and one, sulcatone, was more attractive than methyl salicylate. Blends of kairomones were then tested for attraction, revealing five blends that were significantly more attractive than methyl salicylate, and could be developed into lures for field testing. The presence of these kairomones in volatile profiles of 17 plant species is described. These findings support the hypothesis that the identified volatiles act as kairomones and function in attraction to host plants.

Seasonal Development, Cumulative Growing Degree-Days, and Population Density of Spotted Lanternfly (Hemiptera: Fulgoridae) on Selected Hosts and Substrates

Seasonal development, cumulative growing degree-days (CUMDD10), and population density of Lycorma delicatula (White) were studied through weekly sampling of 30 plants (5 plants/species, 3 common plus 3 site-specific species per site) at six sites in Pennsylvania in 2019. In total, 24,159 L. delicatula (1,987 egg masses, 1,068 first instars, 239 second instars, 153 third instars, 410 fourth instars, and 20,302 adults) were recorded in 28 wk. Seasonal development followed similar pattern at all sites despite differences in starting, peaking, and ending time for specific life stages. The average CUMDD10 requirement for the onset of the first instars, second instars, third instars, fourth instars, adults, and eggs was 270, 465, 645, 825, 1,112, and 1,825, respectively. Population density ranged from 0 to 207.4, 0-298.9, and 0-9.6/m2 for nymphs, adults, and egg masses, respectively. Significant difference in population density was found between sites, hosts/substrates, and sampling weeks. Favored oviposition substrates included tree-of-heaven and black birch despite egg masses being laid on many other surfaces. Nymphs fed on different hosts in early stages but preferred American beech, tree-of-heaven, black birch, and multiflora rose. Adults were predominately found on tree-of-heaven with preoviposition surge on black birch and red maple. Sizable nymph and adult populations persisted on summer grape throughout the season. Tree-of-heaven played an irreplaceable role in the seasonal development and life history of L. delicatula in the field. Survey and detection activities should focus on tree-of-heaven with management efforts directed to aggregating adults for maximum efficacy.

The Inability of Spotted Lanternfly (Lycorma delicatula) to Vector a Plant Pathogen between its Preferred Host, Ailanthus altissima, in a Laboratory Setting

Simple Summary

The invasive and accidently introduced insect, the spotted lanternfly, is spreading rapidly and becoming abundant in the mid-Atlantic region of the USA. Though this insect prefers to feed on the also invasive tree-of-heaven, its ability to feed on other native and crop plant species is concerning, and therefore eradication and control efforts are underway. These efforts include targeting the difficult to control tree-of-heaven for removal. Recently, researchers have found that a naturally occurring fungus effectively kills the tree-of-heaven and work towards making this fungus publically available is ongoing. Therefore, we tested whether the spotted lanternfly is capable of spreading the pathogen between symptomatic fungus-inoculated tree-of-heaven seedlings or plant material to healthy tree-of-heaven seedlings in a controlled laboratory setting. In these conditions, we found no evidence that this transmission occurred. This included monitoring the seedlings for symptoms and sampling the seedlings and the insects for the fungus. This lack of transmission may indicate that the spotted lanternfly cannot help spread this fungus to other tree-of-heaven.

Abstract

With the recent introduction of the non-native spotted lanternfly (Lycorma delicatula) to the USA, research and concern regarding this insect is increasing. Though L. delicatula is able to feed on many different plant species, its preference for the invasive tree-of-heaven (Ailanthus altissima) is apparent, especially during its later life stage. Therefore, management focused on A. altissima control to help limit L. delicatula establishment and population growth has become popular. Unfortunately, the control of A. altissima is difficult. Verticillium nonalfalfae, a naturally occurring vascular-wilt pathogen, has recently received attention as a potential biological control agent. Therefore, we studied if L. delicatula fourth instars or adults could vector V. nonalfalfae from infected A. altissima material to healthy A. altissima seedlings in a laboratory setting. We were unable to re-isolate V. nonalfalfae from the 45 A. altissima seedlings or from the 225 L. delicatula utilized in this experiment. We therefore, found no support that L. delicatula could effectively vector this pathogen between A. altissima in laboratory conditions. Since L.delicatula’s ability to vector V. nonalfalfae has implications for the dissemination of both this beneficial biological control and other similar unwanted plant pathogens, future research is needed to confirm these findings in a field setting.

No link between nymph and adult coloration in shield bugs: weak selection by predators

Many organisms use different antipredator strategies throughout their life, but little is known about the reasons or implications of such changes. For years, it has been suggested that selection by predators should favour uniformity in local warning signals. If this is the case, we would expect high resemblance in colour across life stages in aposematic animals where young and adults share similar morphology and habitat. In this study, we used shield bugs (Hemiptera: Pentatomoidea) to test whether colour and colour diversity evolve similarly at different life stages. Since many of these bugs are considered to be aposematic, we also combined multi-species analyses with predation experiments on the cotton harlequin bug to test whether there is evidence of selection for uniformity in colour across life stages. Overall, we show that the diversity of colours used by both life stages is comparable, but adults are more cryptic than nymphs. We also demonstrate that nymphs and adults of the same species do not tend to look alike. Experiments on our model system suggest that predators can generalise among life stages that look different, and exhibit strong neophobia. Altogether, our results show no evidence of selection favouring colour similarity between adults and nymphs in this speciose clade.

Use of Molecular Gut Content Analysis to Decipher the Range of Food Plants of the Invasive Spotted Lanternfly, Lycorma delicatula

Spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an introduced highly invasive insect pest in the US that poses a significant risk to forestry and agriculture. Assessing and predicting plant usage of the lanternfly has been challenging, and little is known regarding the lanternfly nymph association with its host plants. In this study, we focused on: (a) providing a protocol for using molecular markers for food plant identification of L. delicatula; (b) determining whether the ingested plant DNA corresponds with DNA of the plants from which the lanternfly was collected; and, (c) investigating the spectrum of ingested plants. We utilized gut contents of third and fourth instar nymphs that were collected from multiple plants; we isolated ingested plant DNA and identified consumed plants. We demonstrated that (a) up to 534 bp of the rbcL gene from ingested plants can be detected in L. delicatula guts, (b) ingested plants in ~93% of the nymphs did not correspond with the plants from which the nymphs were collected, and (c) both introduced and native plants, as well as woody and non-woody plants, were ingested. This information will aid effective the monitoring and management of the lanternfly, as well as predict the lanternfly host plants with range expansion.

Perspective: shedding light on spotted lanternfly impacts in the USA

Spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae) is an invasive phloem-feeding planthopper currently being quarantined in a 24 000 km² area in eastern Pennsylvania, New Jersey, Maryland, and Delaware, with a second population under quarantine in a 46 km² area in Virginia. Because this insect feeds on over 70 species of plants, it has the potential to impact a wide range of sectors, and as a result, there has been great public speculation that the economic impact of SLF could be severe. SLF is a large-bodied voracious feeder that reduces plant resources directly by feeding, and indirectly, from sooty mold that grows on its excrement and blocks photosynthesis. SLF is causing severe damage to vineyards from feeding, and is a significant nuisance pest. It has high potential for spread via human-mediated transport, particularly of egg cases, and may therefore significantly impact commerce in the near future. The ultimate impacts of this insect are not yet known, and will depend upon its longer term impacts on plant and tree health, and the extent to which its range expands. © 2019 Society of Chemical Industry.

Oviposition Substrate Selection, Egg Mass Characteristics, Host Preference, and Life History of the Spotted Lanternfly (Hemiptera: Fulgoridae) in North America

Oviposition substrate selection, egg mass characteristics, host preference, and life history of Lycorma delicatula (White) (Hemiptera: Fulgoridae) were studied in Pennsylvania between 2016 and 2017. Twenty-four substrate types (trees, shrubs, and nonliving materials) were selected by females for oviposition. Tree-of-heaven, black cherry, black birch, and sweet cherry were favored at 62.5% of the types and accounted for 68.5% of the egg masses based on survey results 200 cm above ground. Egg mass density ranged between 0.2 and 75.2 egg masses/m2 with no significant difference among substrate types. Egg mass size ranged between 0 and 192 eggs/egg mass, with 91.8% containing <50 eggs. Significantly larger egg masses were found on sweet and black cherry compared with tree-of-heaven, with significantly higher hatch success on black locust. Eggs hatched between May 2 and June 5 and peaked on 18 May 2017. Tree-of-heaven and summer grape were preferred by nymphs and adults, while multiflora rose and black walnut were favored by the first, second, and the fourth instar nymphs, respectively. The first, second, third, fourth instars and adults lasted for 62 (2 May-3 July), 42 (8 June-20 July), 35 (26 June-31 July), 39 (10 July-18 Aug.), and 114 (24 July-15 Nov.) days, with peaks on 25 May, 22 June, 6 July, 31 July, and 22 Aug., respectively. Adult feed for 2 months before laying eggs in early October. Cumulative degree-days were 0-325, 153-652, 340-881, 567-1,020, 738-1,227, and 942-1,795 for the egg, first, second, third, fourth instar, and adult stage, respectively. Oviposition strategies and development patterns were discussed.

Evolutionary and ecological forces underlying ontogenetic loss of decoy coloration

Predator-based selection has resulted in the repeated evolution of a variety of antipredator traits. Despite the effectiveness of these traits, some species experience shifts or even complete loss of antipredator traits during development. The evolutionary forces that favour such a transition are poorly understood. We sought to comprehend the role of predator-based selection and organismal factors underlying developmental loss of antipredator traits by focusing on decoy coloration in skink lizards. To this end, we studied the ontogenetic loss of decoy tail coloration in three Nearctic skink species. We performed natural history collection surveys and clay-model studies on predation to determine the organismal determinants of decoy coloration (body size and energy content of the tail) and predation based upon size and decoy coloration. We found that decoy coloration was lost during development at a similar size in all three species. Although predation rates on juvenile models were similar for both uniform brown and decoy models, predation rates on adult models with decoy coloration were much higher than those on non-decoy adult models. Overall, our results suggest that predator-based selection is an important factor driving the ontogenetic loss of decoy coloration at similar sizes across these species and might be generalizable to other antipredator traits.

Genome Sequence of a Lethal Vascular Wilt Fungus, Verticillium nonalfalfae, a Biological Control Used Against the Invasive Ailanthus altissima

Verticillium nonalfalfae, a cosmopolitan soil-borne phytopathogen, causes vascular wilt in agricultural crops and perennial woody plants. Select strains of V. nonalfalfae can cause lethal disease in the invasive tree Ailanthus altissima and several have since been utilized as a biological control (biocontrol) against this widespread invader. Here, we report the genome sequence and annotation of V. nonalfalfae strain VnAa140/NRRL 66861.