Effects of the symbiotic bacteria, Caballeronia insecticola, on the life history parameters of Riptortus pedestris (Hemiptera: Alydidae) and their implications for the host population growth.

This study aimed to investigate the effects of symbiosis on the life history of host insects and address their implications at the host population level. We evaluated the effects of symbiotic bacteria Caballeronia insecticola on its host Riptortus pedestris (Fabricus) (Hemiptera: Alydidae) from cohorts for nymphal development, adult survivorship, and female reproduction. Then, life table parameters were compared between symbiotic and apo-symbiotic groups, and the effects of symbiosis on the abundance of R. pedestris were simulated for varying proportions of symbiotic individuals in host populations. We found that symbiosis significantly accelerated the nymphal development and reproductive maturation of females. However, symbiosis incurred survival cost on adult females, reducing their longevity by 28.6%. Nonetheless, symbiotic females laid significantly greater numbers of eggs than the apo-symbiotic during early adult ages. This early reproductive investment negated the adverse effect of their reduced longevity, resulting in the mean lifetime fecundity to not significantly differ between the 2 groups. Indeed, total cohort fecundity of the symbiotic group was 1.3-fold greater than that of the apo-symbiotic group. Life table analysis demonstrated shorter generation time and greater population growth rate in the symbiotic population. Finally, the simulation model results indicate that an increase in the proportion of symbiotic R. pedestris favored the population growth, increasing the population size by 1.9 times for every 25% increase in the proportion of symbiotic individuals. Our study demonstrates that symbiont-mediated changes in the life history parameters of host individuals favor the host population growth, despite substantial reduction in the female longevity.

Fitness implications of low-temperature storage for Eocanthecona furcellata (Hemiptera: Pentatomidae).

Exploring the impact of low-temperature storage on the fitness of natural enemy insects is crucial for practical field applications because this parameter directly influences their potential for population growth and effective pest control. Eocanthecona furcellata (Wolff) (Hemiptera: Pentatomidae) is widely used in biological pest control. This study aimed to identify optimal storage stages, temperatures, and durations for E. furcellata to produce high-quality individuals for practical use. The quality of E. furcellata after storage was evaluated by assessing parameters such as predatory capacity and fecundity, along with age-stage, two-sex life table. The findings revealed that the adult stage was the optimal storage form for E. furcellata, and the most favorable temperature for storage was 12 °C. Adult females had the highest predatory ability after 15 days of storage at 12 °C. Although survival rates declined with prolonged storage, they remained above 50% after 30 days, and longevity, fecundity, and predatory capacity of surviving individuals remained comparable to those of individuals in the control group (rearing at a constant temperature of 26 °C without low-temperature storage). The effects of low-temperature storage extended to the F1 generation of E. furcellata, which exhibited maximum mean longevity, fecundity, net reproductive rate, and mean generation time as well as fastest population growth after 30 days of storage at 12 °C. These results can be used to achieve optimal low-temperature storage conditions for E. furcellata production, particularly for extending its shelf life.

Is Lycorma delicatula (Hemiptera: Fulgoridae) a blooming threat to citrus?

Examining the host range of emerging invasive insects is essential to assess their invasion potential and to anticipate the negative impacts of their spread. The ongoing North American invasion of spotted lanternfly (SLF) [Lycorma delicatula (White, 1845)] threatens agricultural, urban, and natural areas. The survival and development of SLF nymphs on Washington navel orange [Citrus sinensis (L.) Osbeck (Sapindales: Rutaceae)] trees were assessed in a quarantine facility. Results indicated that SLF nymphs can develop to at least the third instar by feeding exclusively on Washington navel orange. This finding suggests that, at least up to the third stage of nymphal development, Washington navel orange might be a suitable host for SLF, highlighting the possibility that this invasive pest represents an unrecognized threat to this globally important crop and possibly to other Citrus species.

Born suckers: the cibarial pump of Philaenus spumarius scales across ontogeny to ensure functional equivalence.

A select group of hemipterans within the suborder Auchenorrhyncha are the only animals that feed exclusively on xylem sap - a nutritionally poor liquid that exists under negative pressure within a plant's xylem vessels. To consume it, xylem-feeding bugs have evolved enlarged cibarial pumps capable of generating enormous negative pressures. A previous study examining the allometry of this feeding model suggested that small xylem feeders pay relatively higher energetic costs while feeding, favouring the evolution of larger-bodied species. However, this interspecific analysis only considered adult xylem-feeding insects and neglected the considerable intraspecific change in size that occurs across the insect's development. Here, we examine the changes in cibarial pump morphology and function that occur during the development of Philaenus spumarius, the common meadow spittlebug. We show that the cibarial pump scales largely as expected from isometry and that the maximum negative pressure is mass independent, indicating that size has no effect on the xylem-feeding capacity of juvenile spittlebugs. We conclude that a first instar nymph with a body mass 2% of the adult can still feed at the >1 MPa tension present in a plant's xylem vessels without a substantial energetic disadvantage.

Electropenetrography Study of Euschistus heros (F.) (Heteroptera: Pentatomidae) Nymphs Feeding on Vegetative Soybean Structures.

The study aimed to understand the feeding behavior of Neotropical brown stink bug nymphs Euschistus heros (F.) on soybean plants during vegetative stage through electropenetrography (EPG) technique. Three distinct phases were identified: non-feeding, pathway, and ingestion. Waveforms representing these phases were consistent across nymphal instars and plant structures, and named Np, Eh1, and Eh2, respectively. Biological interpretations of the waveforms were proposed by integrating visual observations, comparisons with adult waveforms, and histological studies. The waveforms Np, Eh1, and Eh2 were associated with resting/walking, initial stylet-plant contact, and xylem sap ingestion, respectively. Notably, nymphs showed a higher number of Eh1 events and longer durations when feeding on petioles compared to leaves, particularly in younger instars. However, differences between instars diminished in older nymphs. Fifth instars consistently exhibited the highest Eh1 values, and displayed longer xylem ingestion durations compared to other instars. Second instars demonstrated increased xylem ingestion events on petioles compared to leaves. Across plant structures, on petioles, nymphs generally showed longer xylem ingestion durations than on leaf surfaces. Fifth instar consistently had the longest ingestion durations overall. Additionally, statistical differences in xylem ingestion duration were observed between instars within each plant structure, with fifth instars displaying the longest durations. These findings offer valuable insights into the feeding behavior of E. heros nymphs, which could inform the development of more effective pest management strategies for soybean crops.

Ticks infesting terrestrial small mammals in a rural settlement in the Amazonas state, Brazil.

There is limited knowledge about tick diversity in the Amazon region. Here, we survey small terrestrial mammals for tick infestation at the Rio Pardo settlement, Amazonas State, Brazil. Sampling included rainy and dry seasons and four ecotones (primary forest, forest in regeneration, field crops and households). Each animal was inspected for ticks, which, if present, were placed in 70% alcohol and identified. Parasitological indexes were calculated and the presence/absence of ticks on hosts was tested for possible associations with independent variables (ecotone, host sex, host order, host family, host age and season). A total of 208 small mammals were captured, 47 individuals (10 species) in the primary forest, 124 (15 species) in the forest in regeneration, 11 (7 species) in the field crops, and 26 (4 species) in the households. A total of 14 small mammals were infested by ticks (overall prevalence: 6.7%; 95% CI: 3.72 - 11.04%), which consisted of 51 specimens that were identified into four species, as follows: Amblyomma humerale (32 nymphs); Ixodes luciae (6 females); Amblyomma coelebs (1 nymph); and Ornithodoros mimon (1 larva). In addition, 11 larvae were retained as Amblyomma spp. Only host order showed association (P = 0.002) with tick infestation, with marsupials 5.5 times more infested than rodents. Our record of O. mimon on D. marsupialis is the first on this host species, and the first record of a Argasidae tick in the Brazilian state of Amazonas. To the best of our knowledge, this is the first study that actively screened free-living terrestrial small mammals and provided data on prevalence, mean intensity and mean abundance of tick infestations in the Brazilian Amazonas state.

Life history data of four populations of Triatoma mexicana (Hemiptera: Reduviidae) from Central Mexico.

Triatomine bugs are vectors for the Trypanosoma cruzi Chagas parasites, the etiological agent for Chagas disease. This study evaluated 6 epidemiologically significant behaviors (development time, number of blood meals required for molting to the next instar, mortality rate, aggressiveness, feeding duration, and defecation delay) across 4 populations of Triatoma mexicana Herrich-Schaeffer (Heteroptera: Reduviidae), a major T. cruzi vector in Central Mexico. We collected triatomines from areas characterized by high (HP), medium (MP), medium-high (MHP), and low (LP) prevalence of human T. cruzi infection. The MHP population had the shortest development time, <290 days. Both the HP and MP populations required the most blood meals to molt to the next instar, with a median of 13. Mortality rates varied across all populations, ranging from 44% to 52%. All of the tested populations showed aggressive behavior during feeding. All populations shared similar feeding durations, with most exceeding 13 min and increasing with each instar. Quick defecation, during feeding, immediately after or less than 1 min after feeding, was observed in most nymphs (78%-90%) from the MP and MHP populations and adults (74%-92%) from HP, MP, and MHP populations. Though most parameters suggest a low potential for T. mexicana to transmit T. cruzi, unique feeding and defecation behaviors in 3 populations (excluding the LP group) could elevate their epidemiological importance. These population-specific differences may contribute to the varying prevalence rates of T. cruzi infection in areas where T. mexicana is found.

New report of Haemaphysalis longicornis (Ixodida: Ixodidae) in Mecklenburg County, Virginia from field collections.

Haemaphysalis longicornis (Neumann) was first established in New Jersey and has rapidly spread across most of the eastern United States. This tick has the potential to infest a wide variety of hosts and can reproduce quickly via parthenogenesis, presenting a new threat to animal health. Here we report the first record of a single H. longicornis tick in Mecklenburg County, Virginia, from incidental field collections of ticks. In addition to H. longicornis, we collected 787 Amblyomma americanum, 25 Dermacentor variabilis, 6 Ixodes affinis, 1 Haemaphysalis leporispalustris, and 1 Amblyomma maculatum using standard dragging and flagging techniques. The expansion of H. longicornis will have economic consequences for livestock producers in south-central Virginia, who must now manage this species. Enhanced surveillance is needed to fully understand its growing geographic distribution in the United States and the subsequent consequences of its spread.

Prosapia bicincta (Hemiptera: Cercopidae) abundance, plant associations, and impacts on groundcover in Hawai'i Island rangelands.

The twolined spittlebug, Prosapia bicincta (Say), is a major economic pest of forage grass and turfgrass. Prosapia bicincta was first detected in rangelands on Hawai'i Island in 2016 and has since spread to an estimated 72,000 ha in the North and South Kona districts. This study aimed to quantify P. bicincta abundance, plant associations, and impacts on groundcover over time. Monthly surveys of P. bicincta nymphs and adults were conducted from February 2018 to September 2022 along 17 established 100-m transects at 4 ranches located in Kona, Hawai'i Island, spanning an elevation gradient from 519 to 1,874 m above sea level (a.s.l.). Monitoring revealed P. bicincta occurs from 519 to 1,679 m a.s.l., primarily in Kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.)) Morrone (Poales: Poaceae) pastures. Peaks in P. bicincta abundance coincided with the wet season, with most activity occurring from April to October and little to no activity between November and March. Mid elevation (1,000-1,300 m) transects had significantly higher mean P. bicincta abundance (126 nymphs/m2) relative to low (500-999 m) (64 nymphs/m2) and high elevations (>1,300 m) (20 nymphs/m2). Sites with the highest abundance of P. bicincta were also associated with the greatest decrease in mean grass cover (30%) and were replaced by forbs, bare ground, and shrubs. Grasses accounted for 72% of the total P. bicincta detections, with the remaining plants comprised of legumes (16%), sedges (6%), and forbs (6%). Twenty new P. bicincta plant associations were found. This information will help improve the effectiveness of management to suppress populations below economic thresholds.

Macronutrient regulation in nymphs of the two-spotted cricket, Gryllus bimaculatus (Orthoptera: Gryllidae).

Crickets have been extensively studied in recent insect nutritional research, but it remains largely unexplored how they balance the intake of multiple nutrients. Here, we used the nutritional geometry framework to examine the behavioural and physiological regulation of dietary protein and carbohydrate in nymphs of the two-spotted cricket, Gryllus bimaculatus (Orthoptera: Gryllidae). Growth, intake, utilization efficiencies, and body composition were measured from the eighth instar nymphs that received either food pairs or single foods with differing protein and carbohydrate content. When food choices were available, crickets preferentially selected a carbohydrate-biased protein:carbohydrate (P:C) ratio of 1:1.74. During this nutrient selection, carbohydrate intake was more tightly regulated than protein intake. When confined to nutritionally imbalanced foods, crickets adopted a nutrient balancing strategy that maximized the nutrient intake regardless of the nutrient imbalance, reflecting their omnivorous feeding habit. Intake was significantly reduced when crickets were confined to the most carbohydrate-biased food (P:C = 1:5). When nutrients were ingested in excess of the requirements, the post-ingestive utilization efficiencies of these nutrients were down-regulated, thereby buffering the impacts of nutrient imbalances on body nutrient composition. Crickets reared on the most carbohydrate-biased food (P:C = 1:5) suffered delayed development and reduced growth. Our data provide the most accurate description of nutrient regulation in G. bimaculatus and lay the foundation for further nutritional research in this omnivorous insect.

Effects of parental diet on Mormon cricket egg diapause, embryonic development rate, and periodic outbreaks.

Transgenerational phenotypic modification can alter organismal fitness, population demographics, and community interactions. For ectotherms, both dietary composition and temperature have important effects on organismal fitness, but they are rarely investigated together. Mormon crickets Anabrus simplex are capable of diapausing as eggs in the soil for multiple years with duration largely dependent on cumulative heat units or degree days. Because Mormon crickets can be abundant in the landscape in one year and disappear suddenly the next, I asked: does parental nutrition affect the duration of egg diapause? Beginning in the ultimate nymphal instar, Mormon crickets were fed a diet high in protein, one equal in protein to carbohydrate, or a diet high in carbohydrates and the time for eggs to develop after they were laid was measured. If parental nutrition affects temperature-sensitive egg diapause, then that change in sensitivity to temperature might also alter the relationship between embryonic development rate and temperature. I asked: does parental nutrition affect embryonic development rate as a function of temperature? To this end, I manipulated densities of Mormon cricket nymphs and protein-rich prey (grasshoppers) in field cages, collected eggs from the adult Mormon crickets, and measured the optimal temperature, maximum development rate, and thermal breadth for embryonic development of the offspring. I found that Mormon crickets fed a high protein diet laid eggs with shorter diapause. Consistent with this long-term result, those housed with the most grasshoppers to eat laid eggs that had the fastest maximum development rate, whereas those without grasshoppers laid eggs with slower maximum developmental rates but the broadest thermal breadth. Eggs from Mormon crickets housed with intermediate levels of grasshopper densities had a decline in peak development rate with an increase in density. In addition, Mormon crickets housed with more conspecifics laid eggs with faster development rates, whereas thermal breadth and the temperature optima were not affected by cricket density. As predicted, Mormon cricket diets significantly affected egg diapause and development rates. Contrary to expectations based on observed changes in diet preferences during a Mormon cricket outbreak, Mormon crickets fed high protein diets laid eggs with significantly shorter egg diapause and significantly faster egg development rates. Interestingly, doubling of Mormon cricket density caused eggs to develop in nearly half the time. This latter result indicates that Mormon cricket aggregations promote rapid development of progeny. Moreover, the tight, linear structure of migratory bands in which females intermittently stop to lay eggs assures that the progeny hatch and develop in dense cohorts. In this manner, the banding behavior might carry-over into subsequent generations as long as cohorts are dense and protein is available. With band thinning or protein restriction, females spread their bet-hedging and progeny remain longer as eggs in the soil.

Toxicological assessment of cadmium exposure through Hyphantria cunea larvae on the predation fitness of Arma chinensis.

Heavy metals are defined as an abiotic factor that affects the efficiency of biological pest control. This study constructed a cadmium (Cd)-polluted artificial diets-Hyphantria cunea-Arma chinensis food chain to analyze the effects of Cd exposure on the ability of A. chinensis to control H. cunea. The results revealed that Cd was transferred through the artificial diet to H. cunea larvae and A. chinensis nymphs via a biological amplification effect. After feeding on Cd-accumulated H. cunea larvae, the body weight of A. chinensis nymphs reduced, mortality increased, developmental duration prolonged, and the expression of growth regulatory genes (EX, cycE, and MER) decreased. Cd activated the antioxidant defense system of the nymphs, accompanied by a significant enhancement in the contents of H2O2 and MDA, marked damage to the midgut sub-microstructure, and a remarkable induction in the expression of genes crucial for the mitochondrial pathway/ER stress-apoptosis pathway. Cd significantly diminished the contents of total amino acids, glucose, free fatty acids, and expression of the genes (HK2, PFK, IDH1, and IDH2) essential for the TCA cycle and glycolysis in the nymphs. The preference of the A. chinensis nymphs to Cd-treated H. cunea larvae was evidently reduced. Cd diminished the search-ability, food intake, instantaneous attack rate, and maximum theoretical daily food intake but prolonged the feeding time of the nymphs. Taken together, Cd exposure reduces the ability of A. chinensis nymphs to control H. cunea and provides a new challenge for the efficiency of insect pest control using natural enemies. These findings have important reference value for optimizing pest control strategies in heavy metal polluted areas.

The mlpt smORF gene is essential for digestive physiology and molting during nymphal stages in the kissing bug Rhodnius prolixus.

Chagas disease affects around 8 million people globally, with Latin America bearing approximately 10,000 deaths each year. Combatting the disease relies heavily on vector control methods, necessitating the identification of new targets. Within insect genomes, genes harboring small open reading frames (smORFs - < 100 amino acids) present numerous potential candidates. In our investigation, we elucidate the pivotal role of the archetypal smORF-containing gene, mille-pattes/polished-rice/tarsalless (mlpt/pri/tal), in the post-embryonic development of the kissing bug Rhodnius prolixus. Injection of double-stranded RNA targeting mlpt (dsmlpt) during nymphal stages yields a spectrum of phenotypes hindering post-embryonic growth. Notably, fourth or fifth stage nymphs subjected to dsmlpt do not undergo molting. These dsmlpt nymphs display heightened mRNA levels of JHAMT-like and EPOX-like, enzymes putatively involved in the juvenile hormone (JH) pathway, alongside increased expression of the transcription factor Kr-h1, indicating changes in the hormonal control. Histological examination reveals structural alterations in the hindgut and external cuticle of dsmlpt nymphs compared to control (dsGFP) counterparts. Furthermore, significant changes in the vector's digestive physiology were observed, with elevated hemozoin and glucose levels in the posterior midgut of dsmlpt nymphs. Importantly, dsmlpt nymphs exhibit impaired metacyclogenesis of Trypanosoma cruzi, the causative agent of Chagas disease, underscoring the crucial role of proper gut organization in parasite differentiation. Thus, our findings constitute the first evidence of a smORF-containing gene's regulatory influence on vector physiology, parasitic cycle, and disease transmission.

Wax "Tails" Enable Planthopper Nymphs to Self-Right Midair and Land on Their Feet.

The striking appearance of wax 'tails'-posterior wax projections on planthopper nymphs-has captivated entomologists and naturalists alike. Despite their intriguing presence, the functional roles of these formations remain largely unexplored. This study leverages high-speed imaging to uncover the biomechanical implications of wax structures in the aerial dynamics of planthopper nymphs (Ricania sp.). We quantitatively demonstrate that removing wax tails significantly increases body rotations during jumps. Specifically, nymphs without wax undergo continuous rotations, averaging 4.2 ± 1.8 per jump, in contrast to wax-intact nymphs, who do not complete a full rotation, averaging only 0.7 ± 0.2 per jump. This along with significant reductions in angular and translational velocity from takeoff to landing suggest that aerodynamic drag forces on wax structures effectively counteract rotation. These stark differences in body rotation correlate with landing success: Nymphs with wax intact achieve a near perfect landing rate of 98.5%, while those without wax manage only a 35.5% success rate. Jump trajectory analysis reveals that wax-intact jumps transition from parabolic to asymmetric shapes at higher takeoff velocities and show a significantly greater reduction in velocity from takeoff to landing compared to wax-removed jumps, demonstrating how wax structures help nymphs achieve more stable and controlled descents. Our findings confirm the aerodynamic self-righting functionality of wax tails in stabilizing planthopper nymph landings, advancing our understanding of the complex relationship between wax morphology and aerial maneuverability, with broader implications for wingless insect aerial adaptations and bioinspired robotics.

Direct effects of barley yellow dwarf virus on the performance, parasitoid resistance, and feeding behavior of its vector Sitobion avenae (Hemiptera: Aphididae).

BACKGROUND: The complex interaction between plant viruses and their insect vectors is the basis for the epidemiology of plant viruses. The 'Vector Manipulation Hypothesis' (VMH) was proposed to demonstrate the evolution of strategies in plant viruses to enhance their transmission to new hosts through direct effects on insect vector behavior and/or physiology. However, the aphid vectors used in previous studies were mostly obtained by feeding on virus-infected plants and as a result, it was difficult to eliminate the confounding effects of infected host plants. Furthermore, the mechanisms of the direct effects of plant viruses on insect vectors have rarely been examined comprehensively. RESULTS: We fed Sitobion avenae on an artificial diet infused with a purified suspension of Barley yellow dwarf virus (BYDV) PAV strain to obtain viruliferous aphids. We then examined their growth and reproduction performance, resistance to the parasitoid Aphidius gifuensis Ashmead, and feeding behavior. The results indicate that (1) viruliferous aphids had a shorter life span and a lower relative growth rate at the nymphal stage; (2) A. gifuensis had a lower parasitism rate, mummification rate, and emergence rate in viruliferous aphids; (3) Viruliferous aphids spent more time on non-probing and salivation behavior and had a shorter total duration of penetration and ingestion compared with healthy conspecifics. CONCLUSION: These results suggest that plant virus infection may directly alter vector fitness and behavior that improves plant virus transmission, but not vector growth. These findings highlight the mechanisms of VMH and the ecological significance of vector manipulation by plant viruses, and have implications for plant virus disease and vector management. © 2024 Society of Chemical Industry.

Sublethal and transgenerational effects of broflanilide on the citrus red mite, Panonychus citri.

BACKGROUND: The citrus red mite, Panonychus citri is a serious pest of the citrus industry and has developed resistance to many acaricides. Broflanilide is a novel meta-diamide insecticide that binds to a new site on the γ -aminobutyric acid receptor with high potency against pests. However, little information has been reported about its effect on the citrus red mite. RESULTS: Broflanilide exhibited higher toxicity to female adults and eggs of a laboratory strain of P. citri The median lethal concentration (LC50), 9.769 mg/L and 4.576 mg/L, respectively) than other commonly used acaricides and was also toxic to two P. citri field strains. Broflanilide treatment with LC10, LC20, and LC30 significantly decreased the fecundity and longevity of female adults of F0 P. citri compared with the control. The duration of larva, protonymph, deutonymph and adult, and total life span in the F1 generation were significantly reduced after treatment of F0 with broflanilide. Population parameters, including the intrinsic rate of increase (r) and finite rate of increase (λ), were significantly increased, and the mean generation time (T) of F1 progeny was significantly reduced in the LC20 treatment. The predicted population size of F1 increased when parental female adults were treated with sublethal concentrations. CONCLUSION: Broflanilide had high acaricidal activity toward P. citri, and exposure to a sublethal concentration significantly inhibited the population growth of F0. The transgenerational hormesis effect is likely to cause population expansion of F1. More attention should be paid when broflanilide is applied to control P. citri in citrus orchards. © 2024 Society of Chemical Industry.

Functional responses of two species of predatory mites (Acari: Phytoseiidae) to eggs and first-instar nymphs of Bactericera Gobica Logniova (Homoptera: Psyllidae).

The goji berry psyllid, Bactericera gobica Logniova (Homoptera: Psyllidae), is one of the most important pests on goji berry plants (Lycium barbarum L.), whose fruits are widely used in traditional Chinese medicine and food. However, chemical control is still the predominant control strategy of this pest. Recently, two species of predatory mites, Neoseiulus setarius Ma, Meng & Fan and Neoseiulus barkeri Hughes were found to be associated with B. gobica in China. To assess their predation potential against B. gobica, the functional responses of these two phytoseiid species feeding on different densities (2, 4, 8, 12, 16, 24 and 32 individuals) of B. gobica eggs and 1st instar nymphs were compared at a temperature of 25ºC ± 1º C. Logistic regression analysis revealed that both predatory mite species exhibited type Holling-II functional responses on eggs and 1st instar nymphs of B. gobica, with the predation number increased for both predators as the density of prey increased. Overall, N. setarius consumed more prey compared to N. barkeri across all levels of prey densities. Meanwhile, the highest attack rate (α = 0.0283), the lowest handling time (Th = 1.1324 h prey- 1), and the highest estimated maximum predation rate (T/Th = 21.19 prey day- 1) were all observed for N. setarius fed with 1st instar nymphs of B. gobica. These findings suggest that it is worthy considering utilizing N. setarius and N. barkeri as candidate biocontrol agents of B. gobica, with N. setarius appearing to be a more effective predator than N. barkeri.

Bacterial pathogens in Ixodes ricinus collected from lizards Lacerta agilis and Zootoca vivipara in urban areas of Wroclaw, SW Poland- preliminary study.

The aim of this study was to determine the level of infection of Ixodes ricinus ticks with pathogens (Borrelia spp., Rickettsia spp., and Anaplasma spp.) collected from Lacerta agilis and Zootoca vivipara lizards in the urban areas of Wroclaw (SW Poland). The study was carried out in July-August 2020. Lizards were caught by a noose attached to a pole or by bare hands, identified by species, and examined for the presence of ticks. Each lizard was then released at the site of capture. Ticks were removed with tweezers, identified by species using keys, and molecular tests were performed for the presence of pathogens. From 28 lizards (17 specimens of Z. vivipara and 11 specimens of L. agilis) a total of 445 ticks, including 321 larvae and 124 nymphs, identified as I. ricinus were collected. A larger number of ticks were obtained from L. agilis compared to Z. vivipara. Molecular tests for the presence of pathogens were performed on 445 specimens of I. ricinus. The nested PCR method for the fla gene allowed the detection of Borrelia spp. in 9.4% of ticks, and it was higher in ticks from L. agilis (12.0%) than from Z. vivipara (1.0%). The RFLP method showed the presence of three species, including two belonging to the B. burgdorferi s.l. complex (B. lusitaniae and B. afzelii), and B. miyamotoi. The overall level of infection of Rickettsia spp. was 19.3%, including 27.2% in ticks collected from Z. vivipara and 17.0% from L. agilis. Sequencing of randomly selected samples confirmed the presence of R. helvetica. DNA of Anaplasma spp. was detected only in one pool of larvae collected from L. agilis, and sample sequencing confirmed the presence of (A) phagocytophilum. The research results indicate the important role of lizards as hosts of ticks and their role in maintaining pathogens in the environment including urban agglomeration as evidenced by the first recorded presence of (B) miyamotoi and (A) phagocytophilum in I. ricinus ticks collected from L. agilis. However, confirmation of the role of sand lizards in maintaining (B) miyamotoi and A. phagocytophilum requires more studies and sampling of lizard tissue.

High-temperature responses of Myzus persicae and its parasitoid Aphidius gifuensis in relation to heat level, duration and developmental stage.

BACKGROUND: Understanding how parasitoids respond to temperature is crucial for improving biological control strategies under the context of global warming. This study examined the suitability of Myzus persicae and its parasitoid Aphidius gifuensis to varying temperature conditions, as well as the stage-specific response of A. gifuensis to high temperatures. RESULTS: High temperatures had a significant impact on the both M. persicae and A. gifuensis. When exposed to 36°C, M. persicae developed more slowly and produced smaller adults compared to control, regardless of the duration of exposure (2, 4 or 6 h); additionally, the survival rate of M. persicae nymphs sharply decreased under these conditions. Exposure to 36°C for 4 h negatively impacted the development of A. gifuensis. Female parasitoids exposed to 32°C developed into smaller adults, whereas males exposed to all three temperature levels were smaller compared to control group. Female parasitoids exposed to high temperatures, regardless of the specific heat level and duration, exhibited reduced longevity and decreased fecundity. None of the parasitoids exposed to 36°C for 6 h daily developed into adults. Heat treated during early developmental stages (2 and 4 days old) had a greater influence on parasitoid development, whereas heat treatment at 4 and 6 days old had a more significant impact on its fecundity. CONCLUSION: High temperatures not only directly affected the performance of A. gifuensis, but also exerted indirect effects by influencing the quality of the host aphids M. persicae. The deleterious effects of high temperature on larvae can persist into the adult stage, affecting the longevity and reproduction of adults. These findings are important for the utilization of A. gifuensis in the control of M. persicae in warming environments. © 2024 Society of Chemical Industry.

Halyomorpha halys (Hemiptera: Pentatomidae) as the major contributor to early olive drop in northern Italy.

In recent years, a new phenomenon of early olive drop is causing production losses in olive groves throughout northern Italy. To analyze the possible causes, field and laboratory trials were performed to assess the involvement of fungal pathogens and insect pests in this disease. External and internal symptoms of fungal infections or insect-feeding activities were researched. Fungi present in healthy and dislodged olives were investigated. The relationship between olives that fell and Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) infestation was assessed in a controlled infestation trial, and the effectiveness of an insecticidal strategy in reducing early olive drop was tested in open field conditions. A comparable number of fungi, mostly endophytes, were isolated and identified from both healthy and dislodged olives. The damage observed on dislodged olives was primarily ascribed to pentatomids feeding activity. Six stink bugs species were found in olive canopies, that is, the invasive H. halys, which was by far the most abundant, and Acrosternum heegeri Fieber, Nezara viridula (Linnaeus), Palomena prasina (Linnaeus), Piezodorus lituratus (Fabricious), and Rhaphigaster nebulosa (Poda). Halyomorpha halys caused intense fruit drop in the controlled infestation trial, and its infestation level significantly correlated with the number of olives that fell. Native stink bugs, present in much lower population compared to H. halys, could also partially contribute to early drop of olives. Insect proof net significantly reduced the early olive drop disease, while insecticide applications only partially reduced the stink bugs population density and, proportionally, early olive drop.