Density Of Nymphs Research Articles

Quantifying the direct and indirect effects of sika deer (Cervus nippon) on the prevalence of infection with Rickettsia in questing Haemaphysalis megaspinosa: A field experimental study

Sika deer (Cervus nippon) are important hosts for all life stages of Haemaphysalis megaspinosa, a suspected Rickettsia vector. Because some Rickettsia are unlikely to be amplified by deer in Japan, the presence of deer may decrease the prevalence of Rickettsia infection in questing H. megaspinosa. As sika deer decrease vegetation cover and height and thereby indirectly cause changes in the abundance of other hosts, including reservoirs of Rickettsia, the prevalence of Rickettsia infection in questing ticks can also change. We investigated these possible effects of deer on the prevalence of infection with Rickettsia in questing ticks in a field experiment in which deer density was manipulated at three fenced sites: a deer enclosure (Deer-enclosed site); a deer enclosure where deer had been present until 2015 and only indirect effects remained (Indirect effect site); and a deer exclosure in place since 2004 (Deer-exclosed site). Density of questing nymphs and the prevalence of infection with Rickettsia sp. 1 in questing nymphs at each site were compared from 2018 to 2020. The nymph density at the Deer-exclosed site did not significantly differ from that at the Indirect effect site, suggesting that the deer herbivory did not affect the nymph density by reducing vegetation and increasing the abundance of other host mammals. However, the prevalence of infection with Rickettsia sp. 1 in questing nymphs was higher at the Deer-exclosed site than at the Deer-enclosed site, possibly because ticks utilized alternative hosts when deer were absent. The difference in Rickettsia sp. 1 prevalence between the Indirect effect and Deer-exclosed sites was comparable to that between the Indirect effect and Deer-enclosed sites, indicating that the indirect effects of deer were as strong as the direct effects. Examining the indirect effects of ecosystem engineers in the study of tick-borne diseases may be more important than previously recognized.

Deer management generally reduces densities of nymphal Ixodes scapularis, but not prevalence of infection with Borrelia burgdorferi sensu stricto

Human Lyme disease–primarily caused by the bacterium Borrelia burgdorferi sensu stricto (s.s.) in North America–is the most common vector-borne disease in the United States. Research on risk mitigation strategies during the last three decades has emphasized methods to reduce densities of the primary vector in eastern North America, the blacklegged tick (Ixodes scapularis). Controlling white-tailed deer populations has been considered a potential method for reducing tick densities, as white-tailed deer are important hosts for blacklegged tick reproduction. However, the feasibility and efficacy of white-tailed deer management to impact acarological risk of encountering infected ticks (namely, density of host-seeking infected nymphs; DIN) is unclear. We investigated the effect of white-tailed deer density and management on the density of host-seeking nymphs and B. burgdorferi s.s. infection prevalence using surveillance data from eight national parks and park regions in the eastern United States from 2014–2022. We found that deer density was significantly positively correlated with the density of nymphs (nymph density increased by 49% with a 1 standard deviation increase in deer density) but was not strongly correlated with the prevalence of B. burgdorferi s.s. infection in nymphal ticks. Further, while white-tailed deer reduction efforts were followed by a decrease in the density of I. scapularis nymphs in parks, deer removal had variable effects on B. burgdorferi s.s. infection prevalence, with some parks experiencing slight declines and others slight increases in prevalence. Our findings suggest that managing white-tailed deer densities alone may not be effective in reducing DIN in all situations but may be a useful tool when implemented in integrated management regimes.

Functional and numerical responses are influenced by the feeding experience of Neoseiulus cucumeris (Acari: Phytoseiidae)

Neoseiulus cucumeris (Oudemans) is a commercially available biocontrol agent against various pests. This generalist predator was reared on cattail pollen for 10 generations (G10) and its quality was evaluated using functional and numerical responses to Tetranychus urticae Koch nymph densities as prey. The experiments were conducted by offering a range of prey densities (2, 4, 8, 16, 32, 64, and 128 nymphs) under standard conditions (25 ± 1ºC, 60 ± 5% RH, and a photoperiod of L16:D8 h). The predator exhibited a type III functional response after ten generations of rearing on cattail pollen (G10), while it was type II when the predator had no experience with pollen (G0). The highest estimated maximum predation rate (T/Th) was in G0 (127 prey/day), and the lowest was in G10 (85 prey/day); while, the observed maximum predation rate (OMPR) in the mentioned generations was 67 and 84 prey/day, respectively. The number of prey consumed and the number of eggs laid by the predator in G10 was significantly more than G0. The effects of predator’s generation, prey density, and their interaction on predation and oviposition rate (on T. urticae) were statistically significant. Therefore, because of the higher predation and oviposition rate, and efficient quality of mass-reared predators on cattail pollen, it is proposed that this pollen can be an appropriate food source for mass rearing of N. cucumeris.

Sand lizards (Lacerta agilis) decrease nymphal infection prevalence for tick‐borne pathogens Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum in a coastal dune ecosystem

Abstract Understanding which factors determine tick‐borne disease hazard can contribute to effective disease control. In Europe, the hazard of the pathogens Borrelia burgdorferi s.l. and Anaplasma phagocytophilum is determined by local tick densities (mainly Ixodes ricinus) and the reservoir competence of the host species community. Sand lizards (Lacerta agilis) are common hosts for larvae and nymphs of I. ricinus and non‐competent reservoirs for both pathogens. Consequently, high relative abundance of L. agilis is hypothesized to be associated with lower infection prevalence in nymphs. Here, we aimed to test whether this effectively occurs in natural settings. We sampled different habitat types within a heterogenous dune landscape at the Dutch coast and estimated (1) L. agilis densities, (2) host community competence, (3) the density and infection prevalence of questing I. ricinus ticks and (4) the number and infection prevalence of ticks feeding on L. agilis. Captured L. agilis had high tick burdens and contributed substantially to feeding I. ricinus larvae in their natural habitat. B. burgdorferi s.l. and A. phagocytophilum were virtually absent from feeding larvae and nymphs. The nymphal infection prevalence of both pathogens in questing ticks was lower in habitat types where L. agilis was more abundant. Hence, L. agilis strongly reduced community competence. The density of questing nymphs was higher in habitat types with denser vegetation and also varied more between habitat types than infection prevalence. As a result, nymphal density had a stronger effect on the density of infected ticks than did nymphal infection prevalence. Synthesis and applications. Coastal dune habitats favourable for L. agilis have lower densities of questing nymphs and a lower human infection hazard. These results might be applicable to similar ecosystems where L. agilis is present. From a public health perspective, this underlines the importance of preserving early successional habitat, as encroaching shrubs are associated with higher tick‐borne disease hazard, and vegetation removal might be a solution to reduce hazard in coastal dunes. The high degree of spatial heterogeneity in the abundance of tick‐borne pathogens also poses opportunities to manage recreational activities to limit human exposure to tick‐borne diseases.

Ixodes ricinus density, Borrelia prevalence and the density of infected nymphs along an urban-rural gradient in southern England.

Ticks are found across a range of habitats, with woodland being particularly important for high densities and prevalence of Borrelia infection. Assessments of risk in urban woodland can be difficult if there are low densities and small sample sizes for Borrelia prevalence estimates. This study targeted six urban woodlands with established tick populations, as well as six woodlands in peri-urban zones and six woodlands in rural zones in and around the cities of Bath and Southampton, in the South of England. Nymph densities were estimated, and 100 nymphs were tested from each of the 18 woodlands studied. Ixodes ricinus ticks were found in all woodlands surveyed, and overall density of nymphs (DON) per 100 m2 was 18.17 in urban woodlands, 26.0 in peri-urban woodlands and 17.67 in rural woodlands. Out of 600 nymphs tested across urban woodlands, 10.3% were infected with Borrelia. The same proportion of nymphs collected in rural woodlands were positive for Borrelia. In peri-urban woodlands, 10.8% of nymphs tested positive. Across both cities combined, density of infected nymphs (DIN) was 2.73 per 100 m2 in peri-urban woodland, 1.87 per 100 m2 in urban woodland and 1.82 per 100 m2 in rural woodland. Overall, DON, Borrelia prevalence and DIN did not differ significantly along an urban-rural gradient. This suggests the risk of Lyme borreliosis transmission could be similar, or perhaps even elevated in urban woodland if there is higher public footfall, subsequent contact with ticks and less awareness of the risks. This is particularly important from a public health perspective, as Borrelia garinii dominated across the gradient and this genospecies is linked to neuroborreliosis.

Identification of Resistance Traits Against Whiteflies, Bemisia tabaci in Certified Varieties and Promising Strains in Field and Semi-Field Experiments

Al-Issa, Z., M.N. Salti, M. Nabahan and A. Khalifa. 2023. Identification of Resistance Traits Against Whiteflies, Bemisia tabaci in Certified Varieties and Promising Strains in Field and Semi-Field Experiments. Arab Journal of Plant Protection, 41(2): 173-182. https://doi.org/10.22268/AJPP-41.2.173182 Plants have developed defense systems to cope with pests’ challenge, especially insects to reduce their damage. In this study, some resistance traits in 30 cotton (Gossypium hirsutum) genotypes against cotton’s whitefly, Bemisia tabaci (Genn.) were evaluated through semifield experiments, where antixenosis of certified varieties and promising strains to the insect where studied by designing adhesive cage placed on leaves of the plant third upper, insect development from egg to adult were regularly observed and rates of development and survival, lifespan, sex ratio, and total emergence of adults were monitored. Preference test was conducted through recording numbers of different insect stages in 1cm2 area. Field experiments were carried out by planting cotton genotype for two successive seasons (2018, 2019). Insect density was evaluated by measuring whiteflies density every 15 days until the end of the growing season. During the 2020 season, trichome density in 1cm2 area was determined and their length and diameter were also determined at the 8 th node of cotton genotypes. The results showed that no significant differences among cotton genotype in relation to insect survival rate, lifespan, sex ratio, and emergence rate of adult. This study revealed that there were significant differences in trichome density in 1 cm2 of leaf area ranged between 86.33 to 160.7/cm2 . The correlation was significantly negative between egg and trichome density (R= -0.984). However, no significant correlation between length and diameter of trichome with nymph and egg density. The egg density varied from 32 to 54 egg/cm2 , whereas nymph’s density varied between 3.8 to 6.1 181 Arab J. Pl. Prot. Vol. 41, No. 2 (2023) nymphs/cm2 , and the variety Raqqa 5 had the highest density of whitefly nymphs and eggs during the two seasons. Whiteflies density peak was around mid-September and started to decline until mid-October. The results obtained suggested that there is a role for trichome density in resistance to whiteflies and there aren’t antixenosis between studied cotton’s genotypes. There is a need to investigate cotton genotypes from different cotton species such as G. arboreum, G. barbadens, G. thuberi for the presence of insect resistance traits. Incorporation of such resistance in cotton cultivars is a key for sustainable pest management. Keywords: cotton’s whiteflies, egg number, nymph number, resistance traits, preference, trichome

Umbonia crassicornis (Amyot & Serville, 1843) (Hemiptera: Membracidae) nymphal aggregation size and density affect host plant and treehopper growth

There was a significant negative relationship between the density of Umbonia crassicornis (Amyot & Serville, 1843) aggregations and the average length of the newest growth on its host plant, Lysiloma latisiliquum Benth. (Fabaceae). There was also a significant negative relationship between aggregation size and the dry mass of the teneral adults of both sexes. Teneral female U. crassicornis were significantly longer and had a significantly greater dry mass than their male siblings. I suggest that feeding by treehopper nymphs reduces the nutrient pool of the host plant, resulting in reduced plant and treehopper growth.

Impact of green space connectivity on urban tick presence, density and Borrelia infected ticks in different habitats and seasons in three cities in southern England

Understanding the effects of local habitat and wider landscape connectivity factors on tick presence, nymph density and Borrelia species (spp.) prevalence in the tick population is important for identifying the public health risk from Lyme borreliosis. This multi-city study collected data in three southern England cities (Bath, Bristol, and Southampton) during spring, summer, and autumn in 2017. Focusing specifically on urban green space used for recreation which were clearly in urbanised areas, 72 locations were sampled. Additionally, geospatial datasets on urban green space coverage within 250 m and 1 km of sampling points, as well as distance to woodland were incorporated into statistical models. Distance to woodland was negatively associated with tick presence and nymph density, particularly during spring and summer. Furthermore, we observed an interaction effect between habitat and season for tick presence and nymph density, with woodland habitat having greater tick presence and nymph density during spring. Borrelia spp. infected Ixodes ricinus were found in woodland, woodland edge and under canopy habitats in Bath and Southampton. Overall Borrelia spp. prevalence in nymphs was 2.8%, similar to wider UK studies assessing prevalence in Ixodes ricinus in rural areas. Bird-related Borrelia genospecies dominated across sites, suggesting bird reservoir hosts may be important in urban green space settings for feeding and infecting ticks. Whilst overall density of infected nymphs across the three cities was low (0.03 per 100 m2), risk should be further investigated by incorporating data on tick bites acquired in urban settings, and subsequent Lyme borreliosis transmission.

Effect of cucumber varieties and some chemical pesticides on the population density of Bemisia tabaci

The current study was conducted to evaluate the sensitivity of three varieties of water cucumber Syrian, Dutch, French and the effectiveness of three insecticides Joker, Harvest, Chase against the tobacco Bemisia tabaci Meza Tabachi in Hawija area - Kirkuk governorate. In the fall from August to December 2020, and the results showed that the Syrian variety made the varieties resistant to Bemisa tabaci, as it reduced the insect population density to 32.40 adult insects/10 leaves and 28.75 nymphs / 16. cm2 in. As for the French and Dutch cultivars 44.85, 44.38 adults / 10 leaves and 40.77 and 39.95 nymphs / 16 cm2 respectively with insecticidal effect on the insect, the results showed that the joker was the best. More effective in reducing insect populations, where the average density was 32.6 insects/10 leaves and 33.39 nymphs/16 cm2 compared with Shays and Harves, where the average population density was 41, 3 and 47.72. adult. /10 leaves and 36.39 and 39.69 nymph 6 cm2. The lowest population density of insects was recorded in the Syrian cultivar treated with Joker pesticide, with an average of 24.54 insects/10 leaves and 27.26 16 cm nymphs. All pesticides showed better efficiency in reducing insects. One day of spraying, then its efficiency began to decline after the third and seventh days of spraying, while the lowest population density of nymphs was recorded after the seventh day of spraying with pesticides, and the lowest population density was 24.52 insects/10. Leaves and 9.81 nymphs/16 cm2 after the second spray of pesticides compared to the previous period and the first spray with an average population density of 53.91, 33.45 adults/10 leaves and 48, 53 and 21.07 nymphs/16 cm2 respectively. The Joker was marked by low adult population density after 1 and 3 days for each of the first sprays, so what is it? On average, after 1 and 3 days of spraying 3.21, 4.77, 2.76, 3.76 insects/10 leaves, respectively, and for spraying days of nymphs 8.66, 4.88 and 3.88 nymphs were counted. / 16 cm2 each, respectively

Modeling Effects of Vertebrate Host Exclosures and Host-Targeted Acaricides on Lone Star Tick (Amblyomma americanum, L.) Infestations.

We used a spatially explicit model to simulate the potential effects of exclosures and acaricides targeted at medium-sized mammalian hosts on the local distribution and abundance of lone star ticks (Amblyomma americanum) within forestlands of the southeastern United States. Both exclosures and acaricides were successful in markedly reducing the densities of all off-host tick life stages inside the treatment areas. Densities dropped to almost zero immediately inside the edges of the exclosures, with noticeably depressed densities extending outward 30 to 60 m from the exclosures, and the simulated exclosures maintained their effectiveness as their sizes were decreased from 4.5 to 2.25 to 0.8 ha. Densities exhibited a smooth gradient across the edges of the acaricide-treated areas, with depressed densities extending ≈100 m outward from the edges, but with perceptible densities extending ≈60 m inward from the edges; thus, the simulated acaricide areas lost their effectiveness as size was decreased to slightly less than one-half the diameter of the activity range of the targeted host. Our simulation results indicated that off-host nymph densities responded to reductions of medium-sized host densities. These results suggest that targeting acaricides at medium-sized hosts may be an effective, and currently under-utilized, method for tick suppression.

Patterns and Ecological Mechanisms of Tick-Borne Disease Exposure Risk in Acadia National Park, Mount Desert Island, Maine, United States.

National parks are unique and significant vector-borne pathogen transmission settings, engaging over 300 million people in outdoor recreation per year. In this study, we integrated vector surveys and ecological habitat feature data in spatial models to characterize tick-borne disease exposure risk in Acadia National Park (ANP), Maine. To determine the broad-scale patterns of blacklegged tick Ixodes scapularis Say (Acari: Ixodidae) densities in ANP, we conducted host-seeking tick collections at 114 sites across the park over two years. Using these tick survey data and geospatial landscape feature data (i.e., land cover, elevation, forest patch size, and aspect) we developed a random forest model of nymphal tick density. We found that host-seeking tick density varies significantly across the park and is particularly high in areas characterized by deciduous forest cover and relatively low elevation. To explore potential fine-scale ecological drivers of tick density spatial patterns, we quantified microclimate conditions, host activity, and vegetation characteristics at a subset of 19 sites. We identified significant differences in microclimate conditions but not host activity or vegetation metrics across broad-scale landscape feature classes. Mean temperature and mean humidity were correlated to nymphal densities and therefore may provide a mechanistic link between landscape features and blacklegged tick densities. Finally, we detected multiple tick-borne pathogens in both ticks and small mammals sampled in ANP, including Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum. Our findings demonstrate the value of using ecological metrics to estimate vector-borne disease exposure risk and provide insight into habitat characteristics that may drive tick-borne disease exposure risk.

Effect of arbuscular mycorrhizal fungi on the responses of Ageratina adenophora to Aphis gossypii herbivory.

The invasive weed Ageratina adenophora can form a positive symbiotic relationship with native arbuscular mycorrhizal fungi (AMF) to promote its invasion ability. However, the function of AMF during the feeding of Aphis gossypii in A. adenophora was poorly understand. This study aimed to investigate the effects of two dominant AMF (Claroideoglomus etunicatum and Septoglomus constrictum) on A. adenophora in response to the feeding of the generalist herbivore A. gossypii. The results showed that A. gossypii infestation could significantly reduce the biomass, nutrient and proline contents of A. adenophora, and increase the antioxidant enzyme activities, defense hormone and secondary metabolite contents of the weed. Compared with the A. gossypii infested A. adenophora, inoculation C. etunicatum and S. constrictum could significantly promote the growth ability and enhanced the resistance of A. adenophora to A. gossypii infestation, and the aboveground biomass of A. adenophora increased by 317.21% and 114.73%, the root biomass increased by 347.33% and 120.58%, the polyphenol oxidase activity heightened by 57.85% and 12.62%, the jasmonic acid content raised by 13.49% and 4.92%, the flavonoid content increased by 27.29% and 11.92%, respectively. The survival rate of A. gossypii and density of nymphs were significantly inhibited by AMF inoculation, and the effect of C. etunicatum was significantly greater than that of S. constrictum. This study provides clarified evidence that AMF in the rhizosphere of A. adenophora are effective in the development of tolerance and chemical defense under the feeding pressure of insect herbivory, and offer references for the management of the A. adenophora from the perspective of soil microorganisms.

Woolly whitefly in agrocenoses of citrus crops of Abkhazia and the eff ectiveness of chemical plant protection products

The woolly whitefly (Aleurothrixus floccosus Maskell), a species of neotropical origin, is a new pest of mandarin orange in Abkhazia. The invasive range of the species has been developing since 1959 and now covers Europe, North America, Africa, the Middle East and East Asia. It was recorded in Abkhazia in spring, 2017. The studies were conducted in 2016-2021 in all regions of Abkhazia by means of standard methods. According to the six-year study of the distribution and development of the phytophage population in the territory of Abkhazia, the species has dramatically increased in number and spread throughout all regions of the country. The identification of the pest was carried out in 2020, but the vector of its penetration into Abkhazia is yet to be clarified. Most likely, A. floccosus was introduced in Abkhazia with planting material of citrus crops. The first colonies of woolly whitefly are recorded in late May-June, followed by a rapid growth of the pest population. The development of the colony reaches its maximum by September, with a density of imago and nymphs of 102.2-152.3 units/leaf. The bioefficacy of different chemical insecticides was evaluated: organophosphorus compounds (Bi-58 Top, KE, with dimethoate as an active ingredient, consumption rate of 2 l/ha), neonicotinoids (Confidor Extra, VDG, active ingredient: imidacloprid, consumption rate of 0.4 kg/ha and Gazelle, RP, active ingredient: acetamipride, consumption rate of 0.15 and 0.5 kg/ha), chitin synthesis inhibitors (Applaud, SP, active ingredient: buprofezin, consumption rate of 0.5 and 1.0 kg/ha). Trials were set in August-September. Treatment of plants was carried out in triplicate against the background of treatment with Product 30 Plus, MME (petroleum jelly oil), the consumption rate of 30 l/ha in the third part of February. At the beginning of the trial, one leaf of mandarin, on average, had 80.2-89.4 whiteflies. From mid-August till the end of September, the number of whitefly colonies increased 1.52 times in control. The use of the insecticide Confidor Extra, WDG, 0.4 kg/ha and variants with increased rates of consumption of insecticides Apploud, SP, 1.0 kg/ha and Gazelle, RP, 0.5 kg/ha (triple treatment) appeared to be the most effective with the biological efficiency of 80.0, 86.7 and 85.8 %, respectively. Dimethoate-based organophosphorus insecticide, traditionally used in agrocenoses of citrus crops, showed insufficient effectiveness (70.0 %).

No net effect of host density on tick-borne disease hazard due to opposing roles of vector amplification and pathogen dilution.

To better understand vector‐borne disease dynamics, knowledge of the ecological interactions between animal hosts, vectors, and pathogens is needed. The effects of hosts on disease hazard depends on their role in driving vector abundance and their ability to transmit pathogens. Theoretically, a host that cannot transmit a pathogen could dilute pathogen prevalence but increase disease hazard if it increases vector population size. In the case of Lyme disease, caused by Borrelia burgdorferi s.l. and vectored by Ixodid ticks, deer may have dual opposing effects on vectors and pathogen: deer drive tick population densities but do not transmit B. burgdorferi s.l. and could thus decrease or increase disease hazard. We aimed to test for the role of deer in shaping Lyme disease hazard by using a wide range of deer densities while taking transmission host abundance into account. We predicted that deer increase nymphal tick abundance while reducing pathogen prevalence. The resulting impact of deer on disease hazard will depend on the relative strengths of these opposing effects. We conducted a cross‐sectional survey across 24 woodlands in Scotland between 2017 and 2019, estimating host (deer, rodents) abundance, questing Ixodes ricinus nymph density, and B. burgdorferi s.l. prevalence at each site. As predicted, deer density was positively associated with nymph density and negatively with nymphal infection prevalence. Overall, these two opposite effects canceled each other out: Lyme disease hazard did not vary with increasing deer density. This demonstrates that, across a wide range of deer and rodent densities, the role of deer in amplifying tick densities cancels their effect of reducing pathogen prevalence. We demonstrate how noncompetent host density has little effect on disease hazard even though they reduce pathogen prevalence, because of their role in increasing vector populations. These results have implications for informing disease mitigation strategies, especially through host management.

Integrating tick density and park visitor behaviors to assess the risk of tick exposure in urban parks on Staten Island, New York

BackgroundPublic green spaces are important for human health, but they may expose visitors to ticks and tick-borne pathogens. We sought to understand, for the first time, visitors’ exposure risk and drivers of tick-preventative behavior in three popular parks on Staten Island, New York City, NY, USA, by integrating tick hazard and park visitors’ behaviors, risk perceptions and knowledge.MethodsWe conducted tick sampling in three parks, across three site types (open spaces, the edge of open spaces, and trails) and three within-park habitats (maintained grass, unmaintained herbaceous, and leaf litter) to estimate tick density during May-August 2019. Human behavior was assessed by observations of time spent and activity type in each site. We integrated the time spent in each location by park visitors and the tick density to estimate the probability of human-tick encounter. To assess visitors’ tick prevention behaviors, a knowledge, attitude, and practices (KAP) survey was administered.ResultsThree tick species (Ixodes scapularis, Amblyomma americanum and Haemaphysalis longicornis) were collected. For all species, the density of nymphs was greatest in unmaintained herbaceous habitats and trails, however, the fewest people entered these hazardous locations. The KAP survey revealed that most respondents (N = 190) identified parks as the main location for tick exposure, but most believed they had minimal risk for tick encounter. Consequently, many visitors did not conduct tick checks. People were most likely to practice tick checks if they knew multiple prevention methods and perceived a high likelihood of tick encounter.ConclusionsBy integrating acarological indices with park visitor behaviors, we found a mismatch between areas with higher tick densities and areas more frequently used by park visitors. However, this exposure risk varied among demographic groups, the type of activities and parks, with a higher probability of human-tick encounters in trails compared to open spaces. Furthermore, we showed that people’s KAP did not change across parks even if parks represented different exposure risks. Our research is a first step towards identifying visitor risk, attitudes, and practices that could be targeted by optimized messaging strategies for tick bite prevention among park visitors.

Sublethal effects of some insecticides on the functional response of Aenasius bambawalei Hayat, 2009 (Hymenoptera: Encyrtidae)

Aenasius bambawalei Hayat, 2009 is one of the most effective natural enemies of Phenacoccus solenopsis Tinsley, 1898. The sublethal effects of dimethoate, imidacloprid, and thiodicarb on the functional response of A. bambawalei to different densities of third instar nymphs of P. solenopsis were evaluated under laboratory conditions. Young females were exposed to the insecticides and then introduced to the host densities of 2, 4, 8, 16, 32, and 64 for 24 h. The results revealed a type III functional response in control and insecticide treatments. The handling time and maximum attack rates of A. bambawalei females were adversely affected by insecticides. The longest handling time and the lowest value of maximum attack rate were observed in thiodicarb treatment, 5.03 h and 4.76, respectively. Therefore, for the simultaneous application of biological and chemical control of P. solenopsis, the influence of insecticides on the functional response behavior of natural enemies must be evaluated.

Starting an invasion: A five-year monitoring program of Halyomorpha halys (Hemiptera: Pentatomidae) in South Tyrol (Northern Italy)

Monitoring action are a fundamental step when non-native species are invding new areas. The phytophagous pest Halyomorpha halys (Stål), originated from north-eastern Asia, is by now introduced in several countries worldwide. Its highly polyphagous behaviour, paired with a relatively high reproduction rate under favourable conditions, makes it an im-portant pest of several agricultural crops. In South Tyrol (Northern Italy), one of the largest con-tiguous apple growing regions in Europe, first adults had been reported in March 2016. Active monitoring techniques, as well as the implementation of a Citizen Science approach, enabled to follow up the spread and settlement of stable populations of H. halys in South Tyrol. Since its first detection, H. halys showed a rapid expansion of colonized area and an increase in population densities from year to year. Established populations coincide mostly with the main apple growing area, namely the Etsch Valley from Meran to Salurn, mainly occupying lower altitudes between 200 and 500 m a.s.l. Since 2019, a further spreading in the western and eastern parts of South Tyrol can be observed. In apple orchards H. hals showed generally a continuous presence throughout the growing season from April to October, with population peaks in the late season. On the other side, populations dynamics and densities of adults and nymphs differ significantly between years ans sureveyed sites. The findings indicate that the application of pheromone baited traps is a good tool for an area wide approach in or-der to get information on its spreading, to pinpoint the main distribution area and to draw a general picture of the population dynamics at a larger scale. On the other side, an area wide approach should be interpreted cautiously, as real population densities might be underesti-mated and do not depict the real situation for singular orchards.

Relevance of Spatial and Temporal Trends in Nymphal Tick Density and Infection Prevalence for Public Health and Surveillance Practice in Long-Term Endemic Areas: A Case Study in Monmouth County, NJ.

Tick-borne diseases are a growing public health problem in the United States, and the US northeast has reported consistently high case rates for decades. Monmouth County, New Jersey, was one of the earliest jurisdictions to report Lyme disease cases in 1979 and reports several hundred cases per year nearly 40 yr later. In the time since, however, tick-borne health risks have expanded far beyond Lyme disease to include a variety of other bacterial pathogens and viruses, and additional vectors, necessitating a continually evolving approach to tick surveillance. In 2017, Monmouth County initiated an active surveillance program targeting sites across three ecological regions for collection of Ixodes scapularis Say (Acari: Ixodidae) and Amblyomma americanum L. (Acari: Ixodidae) as well as testing via qPCR for associated bacterial pathogens. During the first five years of this program (2017-2021), we report high levels of spatiotemporal variability in nymphal density and infection prevalence in both species, limiting the granularity with which human risk can be predicted from acarological data. Nonetheless, broader patterns emerged, including an ongoing trend of A. americanum dominance, risks posed by Borrelia miyamotoi, and the frequency of coinfected ticks. We present some of the first county-level, systematic surveillance of nymphal A. americanum density and infection prevalence in the northeastern US. We also documented a temporary decline in Borrelia burgdorferi that could relate to unmeasured trends in reservoir host populations. We discuss the implications of our findings for tick-borne disease ecology, public health communication, and tick surveillance strategies in endemic areas.

Spatial and temporal heterogeneity of the density of Borrelia burgdorferi-infected Ixodes ricinus ticks across a landscape: A 5-year study in southern England.

The density of Borrelia burgdorferi‐infected Ixodes ricinus nymphs (DIN) was investigated during 2013–2017 across a Lyme disease‐endemic landscape in southern England. The density of nymphs (DON), nymph infection prevalence (NIP), and DIN varied across five different natural habitats, with the highest DIN in woodland edge and high biodiversity woodlands. DIN was significantly lower in scrub grassland compared to the woodland edge, with low DON and no evidence of infection in ticks in non‐scrub grassland. Over the 5 years, DON, NIP and DIN were comparable within habitats, except in 2014, with NIP varying three‐fold and DIN significantly lower compared to 2015–2017. Borrelia garinii was most common, with bird‐associated Borrelia (B. garinii/valaisiana) accounting for ~70% of all typed sequences. Borrelia burgdorferi sensu stricto was more common than B. afzelii. Borrelia afzelii was more common in scrub grassland than woodland and absent in some years. The possible impact of scrub on grazed grassland, management of ecotonal woodland margins with public access, and the possible role of birds/gamebirds impacting NIP are discussed. Mean NIP was 7.6%, highlighting the potential risk posed by B. burgdorferi in this endemic area. There is a need for continued research to understand its complex ecology and identify strategies for minimizing risk to public health, through habitat/game management and public awareness.

Photoperiod controls wing polyphenism in a water strider independently of insulin receptor signalling.

Insect wing polyphenism has evolved as an adaptation to changing environments and a growing body of research suggests that the nutrient-sensing insulin receptor signalling pathway is a hot spot for the evolution of polyphenisms, as it provides a direct link between growth and available nutrients in the environment. However, little is known about the potential role of insulin receptor signalling in polyphenisms which are controlled by seasonal variation in photoperiod. Here, we demonstrate that wing length polyphenism in the water strider Gerris buenoi is determined by photoperiod and nymphal density, but is not directly affected by nutrient availability. Exposure to a long-day photoperiod is highly inducive of the short-winged morph whereas high nymphal densities moderately promote the development of long wings. Using RNA interference we demonstrate that, unlike in several other species where wing polyphenism is controlled by nutrition, there is no detectable role of insulin receptor signalling in wing morph induction. Our results indicate that the multitude of possible cues that trigger wing polyphenism can be mediated through different genetic pathways and that there are multiple genetic origins to wing polyphenism in insects.