Beetle Populations Research Articles

Arthropod Food Webs in the Foreland of a Retreating Greenland Glacier: Integrating Molecular Gut Content Analysis With Structural Equation Modelling.

The Arctic has warmed nearly four times faster than the global average since 1979, resulting in rapid glacier retreat and exposing new glacier forelands. These forelands offer unique experimental settings to explore how global warming impacts ecosystems, particularly for highly climate-sensitive arthropods. Understanding these impacts can help anticipate future biodiversity and ecosystem changes under ongoing warming scenarios. In this study, we integrate data on arthropod diversity from DNA gut content analysis-offering insight into predator diets-with quantitative measures of arthropod activity-density at a Greenland glacier foreland using Structural Equation Modelling (SEM). Our SEM analysis reveals both bottom-up and top-down controlled food chains. Bottom-up control, linked to sit-and-wait predator behavior, was prominent for spider and harvestman populations, while top-down control, associated with active search behavior, was key for ground beetle populations. Bottom-up controlled dynamics predominated during the early stages of vegetation succession, while top-down mechanisms dominated in later successional stages further from the glacier, driven largely by increasing temperatures. In advanced successional stages, top-down cascades intensify intraguild predation (IGP) among arthropod predators. This is especially evident in the linyphiid spider Collinsia holmgreni, whose diet included other linyphiid and lycosid spiders, reflecting high IGP. The IGP ratio in C. holmgreni negatively correlated with the activity-density of ground-dwelling prey, likely contributing to the local decline and possible extinction of this cold-adapted species in warmer, late-succession habitats where lycosid spiders dominate. These findings suggest that sustained warming and associated shifts in food web dynamics could lead to the loss of cold-adapted species, while brief warm events may temporarily impact populations without lasting extinction effects.

Diving into diversity: aquatic beetles of Sukhna Wildlife Sanctuary, Chandigarh, India

The Sukhna Wildlife Sanctuary, located in the Shivalik Hills of Chandigarh, India, encompasses several freshwater ecosystems, including ponds, streams, and marshes. The objective of this study is to fill the current information void regarding the populations of aquatic beetles in the sanctuary. During the period from June to September 2023, a comprehensive study was conducted in the Sukhna Wildlife Sanctuary, resulting in the identification and documentation of 164 specimens of aquatic Coleoptera. These specimens belonged to six species, five genera, and two families in which the Dytiscidae family was found to be the most prevalent. The study findings offer significant insights into the population magnitude and geographical dispersion of aquatic beetles within the investigated settings and show the need for comprehensive surveys to understand the intricate interplay of factors governing beetle distribution.

Multi-strategy cooperative enhancement dung beetle optimizer and its application in obstacle avoidance navigation

Path planning is a crucial component of unmanned driving systems designed to address the challenge of autonomous navigation. This article introduces a novel approach called the multi-strategy cooperative enhanced dung beetle optimization algorithm (RCDBO) and applies it to dispose of path planning issues. Its primary aim is to mitigate the shortcomings of the fundamental dung beetle optimization algorithm (DBO), namely, its tendency to prematurely converge to local optima and its limited global planning capability. Initially, population initialization leverages Bernoulli-based chaotic mapping to enhance diversity and ensure uniform randomness, thereby improving both the quality of initial solutions and optimization efficiency. Subsequently, a random walk strategy is employed to perturb the rolling behavior of the dung beetle population during the initial stage, thus mitigating potential algorithmic local stagnation. Finally, adopting a vertical and horizontal crossover strategy introduces perturbations to the current best value of the dung beetle population, thereby enhancing the DBO method’s global optimization capability during the later stages of evolution. The RCDBO method was evaluated against several well-established swarm intelligence algorithms using twelve benchmark test functions, the CEC2021 test suite, the Wilcoxon rank-sum test, and the Friedman test, to rigorously assess its feasibility. Additionally, the effectiveness of each strategy within the RCDBO framework was validated, and the algorithm’s capability to achieve an optimal balance between global exploration and local exploitation was systematically analyzed through the CEC2021 test suite. Furthermore, in path planning simulation experiments targeting maps of varying sizes and complexities, the RCDBO algorithm, compared to the basic DBO algorithm, results in shorter planned path lengths. In simpler map environments, it exhibits fewer turning points and smoother paths, indicating that the RCDBO algorithm also possesses certain advantages in addressing path-planning challenges.

Seasonal Incidence of Sucking Pests and Their Natural Enemies on Moth Bean [Vigna aconitifolia(Jacq.) Marechal

A field experiment was conducted at the College of Agriculture, NAU, Bharuch (Gujarat) to study the seasonal incidence of sucking pests and their natural enemies and their correlation with weather parameters on moth bean during kharif -2023. The studies on seasonal incidence indicated that jassid infestation began in the 1st week of August (31st SMW) and peaked during the 1st week of September (35th SMW). Whitefly infestation also began in the 1st week of August (31st SMW) achieved its peak during 2nd week of September (36th SMW). The population of thripscommenced from 1st week of August (31st SMW) reached its peak during2nd week of September (36th SMW). The population of ladybird beetle appeared from 2nd week of August (32th SMW) and reached its peak during 2nd week of September (36th SMW). The population of chrysoperla appeared from 2nd week of August(32nd SMW) and reached its peak population during 2nd week of September (36th SMW). Among the different environmental factors, morning relative humidity had a significant positive impact on the jassid and whitefly population. Bright sunshine hours showed significant positive influence on thrips and whitefly population. However no significant correlation was observed between ladybird beetle and Chrysoperla population with weather parameters.

Combining Sentinel-2 Data and Risk Maps to Detect Trees Predisposed to and Attacked by European Spruce Bark Beetle

The European spruce bark beetle is a major disturbance agent in Norway spruce forests in Europe, and with a changing climate it is predicted that damage will increase. To prevent the bark beetle population buildup, and to limit further spread during outbreaks, it is crucial to detect attacked trees early. In this study, we utilize Sentinel-2 data in combination with a risk map, created from geodata and forestry data, to detect trees predisposed to and attacked by the European spruce bark beetle. Random forest models were trained over two tiles (90 × 90 km) in southern Sweden for all dates with a sufficient number of cloud-free Sentinel-2 pixels during the period May–September in 2017 and 2018. The pixels were classified into attacked and healthy to study how detection accuracy changed with time after bark beetle swarming and to find which Sentinel-2 bands are more important for detecting bark beetle attacked trees. Random forest models were trained with (1) single-date data, (2) temporal features (1-year difference), (3) single-date and temporal features combined, and (4) Sentinel-2 data and a risk map combined. We also included a spatial variability metric. The results show that detection accuracy was high already before the trees were attacked in May 2018, indicating that the Sentinel-2 data detect predisposed trees and that the early signs of attack are low for trees at high risk of being attacked. For single-date models, the accuracy ranged from 63 to 79% and 84 to 94% for the two tiles. For temporal features, accuracy ranged from 65 to 81% and 81 to 92%. When the single-date and temporal features were combined, the accuracy ranged from 70 to 84% and 90 to 96% for the two tiles, and with the risk map included, the accuracy ranged from 83 to 91% and 92 to 97%, showing that remote sensing data and geodata can be combined to increase detection accuracy. The differences in accuracy between the two tiles indicate that local differences can influence accuracy, suggesting that geographically weighted methods should be applied. For the single-date models, the SWIR, red-edge, and blue bands were generally more important, and the SWIR bands were more important after the attack, suggesting that they are most suitable for detecting the early signs of a bark beetle attack. For the temporal features, the SWIR and blue bands were more important, and for the variability metric, the green band was generally more important.

Resource pulses drive spatio‐temporal dynamics of non‐native bark beetles and wood borers

Abstract Clear‐fell harvesting of non‐native plantation forests in the southern hemisphere creates large amounts of woody debris that is used for breeding by non‐native bark beetles and wood borers. Limited competition and a shortage of natural enemies allow some invasive pine bark beetles and wood borers to become highly abundant and cause phytosanitary issues. Replicated transects (550–750 m long) of funnel traps baited with alpha‐pinene and ethanol spanning even‐aged Pinus radiata stands were established in New Zealand's largest plantation forest and monitored from pre‐harvest until up to 5 years post‐harvesting to test the effects of harvesting residue resource pulses on the spatio‐temporal population dynamics of Hylurgus ligniperda, Hylastes ater and Arhopalus ferus. Generalised additive mixed model analyses of trap captures of >687,000 H. ligniperda, >7600 H. ater and >5000 A. ferus individuals showed greatly elevated populations for the first 2–3 years post‐harvest. Subsequently, populations returned to very low levels once the resource pulse was exhausted. Spatial patterns of captures reflecting beetle dispersal from breeding material showed a curvilinear decline along the breeding resource gradient by up to 95% from the interior of a recently harvested stand into an adjacent, previously harvested stand with exploited resources. Synthesis and applications. The results show that forest management characterised by ongoing harvesting of neighbouring stands facilitates the build‐up of large populations of bark beetles and wood borers of phytosanitary concern. This is due to recurrent resource pulses caused by the supply of substantial amounts of breeding material from tree felling. Our findings can inform forest planning aimed at avoiding such harvesting patterns, by assisting with the development and implementation of strategies for the management of beetle populations across the landscape. Most beetles dispersed <400 m beyond the source stand edge, although some beetles are likely to have dispersed further. Keeping a distance of 1–2 km between recently felled stands and those scheduled for felling would be expected to reduce rapid population growth. This knowledge can also be used to reduce seedling attack, minimise infestation of logs, and ultimately, mitigate pathway and biosecurity risks, with important implications for forest product exports and quarantine measures.

Unravelling the seasonal dietary dynamics of the endangered garden dormouse (Eliomys quercinus) in Flanders, Belgium

The garden dormouse (Eliomys quercinus) faces significant population declines across Europe, prompting urgent conservation measures. A critical aspect of these efforts is understanding the species’ dietary composition and preferences within specific areas and how this changes throughout the year. We compared garden dormouse diets between two habitats in West Flanders, Belgium with faecal analysis from May to October, covering almost their entire active phase. Our findings revealed a diverse diet of both plant and animal matter, with notable variations between habitats and seasons. Blackberries and other fruits, leaves, and to a lesser extent flowers, were the predominant plant-based food sources in both study areas, with seasonal fluctuations indicating a dietary shift throughout the dormice’s active period. Spring diets consisted primarily of young leaves and flowers, changing to increased fruit consumption in summer. Beetles emerged as a main animal food source throughout the entire active period. Snails were prominently eaten in the woody area, while millipedes prevailed in the diet in the dune environment, both more in spring than later in the active season. These insights highlight the importance of maintaining diverse fruit sources and preserving beetle, snail, and millipede populations for garden dormouse conservation. This study provides valuable insights into dormouse dietary preferences and thus contributes to targeted conservation strategies being essential for the survival of the dormouse.

Spatial distribution and fixed-precision sequential sampling plans for Popillia japonica (Coleoptera: Scarabaeidae) adults in primocane raspberry: influence of foliar insecticides.

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), an invasive species from northern Japan, was first detected in Minnesota in 1968. According to fruit growers and the Minnesota Department of Agriculture, population size and feeding damage has been an increasing concern since 2010. Based on trap-catch data, populations have recently exceeded 4,000 beetles/trap/week during July-August near raspberry fields, and can increase by an order of magnitude within 7-10 days. The primary goals of this study were to assess the spatial distribution of P. japonica adults in raspberry, and to develop and validate a practical fixed-precision sequential sampling plan for grower use. Taylor's Power Law (TPL) regression was used to characterize the beetle's spatial pattern in research plots and commercial fields, either with or without insecticide applications. We then used Green's plan to develop an enumerative sequential sampling plan to estimate P. japonica density in primocane raspberry. Beetle population data were collected at two locations in southern Minnesota, including the Rosemount Research and Outreach Center, and a commercial field near Forest Lake. The TPL results, via slope comparisons, indicated no significant differences in P. japonica spatial pattern between insecticide treated plots versus untreated plots, or among 4 different insecticides (P>0.05). Utilizing all spatial pattern data, we characterized the distribution of P. japonica beetles to be highly aggregated in raspberry, with TPL slopes ranging from b = 1.38 to 1.55; all slopes were found to be >1.0. Although the slopes were not significantly different, we accounted for variability in spatial pattern by using 33 independent data sets, and the Resampling for Validation of Sampling Plans (RVSP) model to validate a sampling plan with a final average precision level of 0.25 (SEM/mean), recommended for integrated pest management (IPM) purposes. The final sampling plan required an average sample number of only 15, 1-m-row samples, while providing high relative net precision (RNP), and thus a cost-effective, efficient sample plan for growers.

Ant-treehopper mutualism affecting biocontrol of Parthenium hysterophorus by Mexican beetle, Zygogramma bicolorata Pallister

Infestation of a treehopper, Gargara malabarica Ananthasubramanian and Ananthakrishnan (Membracidae, Homoptera) on Parthenium hysterophorus L. and also a myrmicine ant, Lophomyrmex quadrispinosus (Jerdon) (Hymenoptera, Formicidae) tending these treehoppers is reported for the first time. The ant-treehopper association interferes with the biological control of P. hysterophorus by Mexican beetle, Zygogramma bicolorata Pallister (Coleoptera, Chrysomelidae). The Parthenium plants with ants supported significantly lesser number of grubs and adults of Mexican beetle compared to plants without ants. Mean number of Mexican beetle eggs was low on plants with ants, but it was non-significant. Further, the ants were observed to be disturbing the adult Mexican beetles from settling on the Parthenium plants, and this presumably led to the less Mexican beetle population.

Efficacy of Biopesticides for controlling major pests of Cucumber (Cucumis sativus L.) in Surkhet District, Nepal

This study evaluated the efficacy of biopesticides against major insect pests of cucumber (Cucumis sativus L.) in Lekbeshi, Surkhet, Nepal. A randomized complete block design experiment was conducted with four treatments: Beauveria bassiana (1 ml/L), Bacillus thuringiensis (Bt) (2 ml/L), Jholmol (1:5 concentration), and an untreated control. After the third spray, B. bassiana reduced red pumpkin beetle populations from 1.4 to 0.4 insects per plant, while Bt reduced fruit fly populations from 2.8 to 1.6 insects per plant, compared to the control (4.2 to 2.2). At 60 days after transplanting, Bt-treated plants were significantly taller (137.45 cm) than control plants (111.28 cm). Fruit damage was lowest in Bt-treated plots (1.8% and 0.69 kg damage weight) compared to the control (3.8% and 0.69 kg). While yield attributes showed no significant differences, total yield was highest in B. bassiana-treated plots (35.58 t/ha) compared to the control (17.8 t/ha). Economic analysis revealed that B. bassiana treatment had the highest benefit-cost ratio (4.19), followed by Bt (2.9), control (2.8), and Jholmol (2.3). These findings suggest that biopesticides, particularly B. bassiana and Bt, can effectively manage major cucumber pests while improving yield and economic returns, offering a sustainable alternative to chemical pesticides in subtropical regions.

Assessing the Impact of Weather Parameters on the Population Dynamics of Insect Pests in Cucurbit Vegetables under Mid-Hill Conditions of Himachal Pradesh

A study focusing on population dynamics of sucking and leaf-eating some insect pests along with their correlation with weather parameters in cucurbits was conducted at research field, Department of Entomology, Dr. YSPUHF, Solan, H.P., India from June-October, 2019 and 2020. The results revealed that Amrasca biguttula biguttula (I), Trialeurodes vaporariorum (W), Aulacophora foveicollis (L), Henosepilachna vigintioctopunctata (F), Liriomyza trifolii (B), Aulacophora sp., were recorded as the major insect pests. In bitter gourd, maximum population of jassids recorded was (2.33/leaf) in first week of August while, maximum whitefly population in bottle gourd (2.96/leaf) during last week of August and in ridge gourd during last week of July (3.76/leaf). The maximum red pumpkin beetle population on bitter gourd (2.4 beetles/plant) and bottle gourd (2.6 beetles/plant) was observed during last week of August while, hadda beetle attained peak population during first and third week of August in ridge gourd (1.0/plant) and bitter gourd (1.1 adults/plant), respectively. Maximum leaf miner infestation (2.7 mines/leaf) in bottle gourd and ridge gourd was observed during first and third week of August. All pest attained maximum population between 30 to 32 SMW when weather parameters values were Tmax: 27.50 to 28.90; Tmin: 20.60 to 20.80 oC; RH: 79 to 80 %; Rainfall: 25.80 to 30.20 mm. Relative humidity and rainfall played major role with non-significant positive influence on the population build-up of these pests in cucurbit crops along with temperature. The present findings on weather-driven pest dynamics can inform strategies to boost crop yields and reduce farmers' economic losses in similar environments.

Plant versus pollinator protection: balancing pest management against floral contamination for insecticide use in Midwestern US cucurbits.

Controlling crop pests while conserving pollinators is challenging, particularly when prophylactically applying broad-spectrum, systemic insecticides such as neonicotinoids. Systemic insecticides are often used in conventional agriculture in commercial settings, but the conditions that optimally balance pest management and pollination are poorly understood. We investigated how insecticide application strategies control pests and expose pollinators to insecticides with an observational study of cucurbit crops in the Midwestern United States. To define the window of protection and potential pollinator exposure resulting from alternative insecticide application strategies, we surveyed 62 farms cultivating cucumber, watermelon, or pumpkin across 2 yr. We evaluated insecticide regimes, abundance of striped and spotted cucumber beetles (Acalymma vittatum [Fabricius] and Diabrotica undecimpunctata Mannerheim), and insecticide residues in leaves, pollen, and nectar. We found that growers used neonicotinoids (thiamethoxam and imidacloprid) at planting in all cucumber and pumpkin and approximately half of watermelon farms. In cucumber, foliar thiamethoxam levels were orders of magnitude higher than the other crops, excluding nearly all beetles from fields. In watermelon and pumpkin, neonicotinoids applied at planting resulted in 4-8wk of protection before beetle populations increased. Floral insecticide concentrations correlated strongly with foliar concentrations across all crops, resulting in high potential exposure to pollinators in cucumber and low-moderate exposure in pumpkin and watermelon. Thus, the highest-input insecticide regimes maintained cucumber beetles far below economic thresholds while also exposing pollinators to the highest pollen and nectar insecticide concentrations. In cucurbits, reducing pesticide inputs will likely better balance crop protection and pollination, reduce costs, and improve yields.

Breeding site segregation and Dutch elm disease fungi carriage percentage of three bark beetle species (Scolytus esuriens, S. chikisanii, and S. japonicus) in a Japanese elm tree in Hokkaido, Japan

ABSTRACT In Japan, three bark beetle species, namely Scolytus esuriens, S. chikisanii, and S. japonicus, have been recently identified as new vectors of Dutch elm disease (DED), although their detailed breeding sites and relation to DED fungi acquisition have not been revealed. We investigated the diameter of branches and a trunk (branch – trunk) at the location of the maternal tunnel (Ømt) and the pupal chamber (Øpc), the distance from the pupal chamber to the bark surface i.e. depth of the pupal chamber (Dpc) on a single Japanese elm tree, and the percentages of bark beetles carrying DED fungi (%bcDED) among those collected from the chamber for three species. The Ømt was 11.0–25.6 cm for S. esuriens, 8.3–23.3 cm for S. chikisanii, and 1.3–3.2 cm for S. japonicus. Therefore, three species were found to exhibit breeding site segregation based on the branch – trunk diameter. The %bcDED were 90.2%, 66.7%, and 40.0% for S. esuriens, S. chikisanii, and S. japonicus, respectively. %bcDED showed an increasing trend with increase in Øpc and Dpc. For DED control, it is necessary to monitor and remove small branches that were previously overlooked to prevent an increase in the population of vector beetles, although %bcDED of bark beetles emerging from small branches tends to be low.

Effectiveness of bioinsecticides for different applications against the main pests of radish

Goal. To determine the technical effectiveness of bioinsecticides against major insect pests of radish (Raphanus sativus (L.) convar. radicula (Pers) Sazon.) grown in open fields, and their impact on plants, yield, and root crop quality. Methods. The study was conducted in accordance with the methods generally accepted in entomology and vegetable growing. During 2020—2022 in open ground conditions on three radish hybrids of different ripeness groups (Adele, Eliza and Stellar) the effectiveness of bioinsecticides Bitoxibacillin-BTU, p. (cell bacteria Bacillus thuringiensis-endospores, titer 1.0 × 10⁹ CFU/ cm3, CS +), 2 l/ha, ACTOVERM FORMULA, CE (abamectin, 18 g/l), 5 l/ha, Lepidocide-BTU, p. (cells of the bacterium Bacillus thuringiensis-var. Kurstaki 9708 L, endospores less than 1 × 109 CFU/cm3), 4 l/ ha, (control). The preparations were applied by spraying plants and fertigation (introduction of fertilizers or pesticides into the irrigation system). Results. On the 14th day after spraying radish plants with Bitoxybacillin-BTU, the population of crucifer flea beetles decreased by 3.9—5.2 times and by 2.8—3.9 times with fertigation. The population of cabbage aphids decreased by 3.9—4.8 and 3.0—3.5 times, and cabbage moth by 5.0—9.0 and 2.7—5.0 times, respectively. The technical effectiveness of Bitoxybacillin-BTU was 76% and 68% against crucifer flea beetles, 78% and 70% against cabbage aphids, and 83% and 73% against cabbage moth. The application of ACTOVERM FORMULA by spraying reduced the population of crucifer flea beetles by 2.6—3.3 times and by 2.5—2.7 times with fertigation. The population of cabbage aphids decreased by 2.9—3.6 and 2.5—2.8 times, and cabbage moth by 2.0—3.0 and 2.0—5.0 times, depending on the radish hybrid. The technical effectiveness of ACTOVERM FORMULA against these pests was 67%, 70%, and 77% with spraying, and 60%, 62%, and 73% with fertigation, respectively. No negative effects from spraying or fertigation with bioinsecticides on radish plants were detected. However, radish plants in the spray treatment had higher height (by 2—3 cm), more leaves per plant (by 1 leaf), and a larger leaf surface area (by 0.2—0.8 thousand m²/ha), depending on the hybrid and product. The root mass increased in treatments with double spraying of ACTOVERM FORMULA and Bitoxybacillin-BTU compared to control and fertigation. The use of bioinsecticides Bitoxybacillin- BTU and ACTOVERM FORMULA (2 treatments) during vegetation ensured yields of 25.6—25.8 t/ha for the Adele hybrid with 93—94% marketable root crops, 24.0—25.1 t/ha for the Eliza hybrid with 94—95% marketable root crops, and 23.2—23.7 t/ha for the Stellar hybrid with 95—96% marketable root crops. The root crops had high dry matter content (Adele: 7.9—8.2%, Eliza: 6.2—6.3%, Stellar: 6.5—6.7%), total sugars (Adele: 2.4—2.5%, Eliza: 2.1—2.2%, Stellar: 2.6%), and ascorbic acid content (Adele: 26.0—26.2 mg/100 g, Eliza: 23.9—24.0 mg/100 g, Stellar: 25.4—25.5 mg/100 g). Conclusions. The application of bioinsecticides Bitoxybacillin-BTU (2 l/ha) and ACTOVERM FORMULA (5 l/ ha) is an effective method for controlling sucking pests in radish crops. Double spraying of radish plants at BBCH 0—9 and BBCH 12—19 with Bitoxybacillin-BTU (2 l/ha) provided control of crucifer flea beetle (76%), cabbage aphid (78%), and cabbage moth (83%). Double spraying with ACTOVERM FORMULA (5 l/ha) at the same stages provided control of crucifer flea beetle (67%), cabbage aphid (70%), and cabbage moth (77%).

Interplay of Abiotic Factors on Various Phytophagous Beetles in Cucumber Under Different Agro-climatic Conditions

Cucumber (Cucumis sativus L.2n = 14) is one of the widely cultivated summer vegetable crops from the gourd family of Cucurbitaceae which is native to India. The climatic conditions of northeast India especially Assam are highly conducive for reproduction of insects, and this region has been considered to be a biodiversity hotspot. Moreover, this region has huge potential for the production of vegetable crops especially cucurbits, but insect pests like fruit flies, pumpkin beetle and sucking pests are major limiting factors for successful cultivation of cucurbits like cucumber etc. Therefore, understanding population fluctuation in the field in relation to losses caused by insect pests are a function of their population dynamics which needs to be thoroughly studied. In view of above factors, an investigation on “Interplay of Abiotic and Biotic Factors on various phytophagous beetles of Cucumber Under Different Agro- Climatic Conditions” was carried out at Horticultural Farm, Assam Agricultural University, Jorhat. Population of phytophagous beetles were recorded on weekly intervals based on number of beetles per plant at seven days interval on 5 randomly selected plants after appearance of the pest. The results showed that during 2019 -2021 summer season, the red pumpkin beetle first appeared on 24th April 2019 and 7th May 2020 with initial population of 4.51 and 2.23 beetles per plant, respectively. However, maximum beetle populations were recorded on 8thMay 2019 and 3rd July 2020 with 6.15 and 6.52 beetles per plant, respectively.

An integrated methods to manage the corn ground beetle (Zabrus tenebrioides Goeze) in wheat field

This study presents a series of experiments on control techniques in the open field trials to monitor and manage the corn ground beetle (Zabrus tenebrioides Goeze) (Coleoptera: Carabidae). The larval stage is particularly harmful, as it feeds on cereal roots and constructs tunnels that damage the wheat crop while residing in the soil. The primary goal of the study was to investigate the effectiveness of various control measures in managing Z. tenebrioides populations and improving wheat yields. Thus, in Qalanchughan village three wheat varieties, the local (Hawler2, Hwler4) and the imported one (Wafia) were tested in the underground (prevention measures) such as organic fertilizers, biofertilizer, chemical fertilizers and chemical pesticides and aboveground (control measure) like biopesticides and conventional pesticides. Regarding the underground prevention measures the lowest population of insect was 0.48 larvae/M2 with the highest biological yield (7132.22 kg/ha) of the cereal found in combined soil and seed treatment (organic humic acid + seed mycorrhizal fungi). The lowest population was found in the local variety Hawler4 which was 0.61 larvae/M2 and the highest population was found in Wafia which was 1.04 larvae/ M2. On the other hand, the aboveground treatments also differ in their effectiveness against Z. tenebrioides thus the lowest population of the larvae in 1/M2 was found in the chemical pesticide, Alphacypermethrin 0.38 larvae/ M2 that was not significantly different from Eucalyptus globulus extract which was 0.60 larvae/ M2. Furthermore, maximum biological yield and treatment efficiency were found in Alphacypermethrin followed by eucalyptus extract which was (5581.11 kg/ha and 108.54). The biopesticides and plant extracts can be used as part of integrated pest management techniques to lower the beetle populations and encourage sustainable farming.

Effect of Weeding Frequency for the Control of Flea Beetle (Podagrica spp) on the Production and Yield of Okra (Abelmoschus esculentus (L.) Moench) in Zaria, Kaduna State

Field trials were carried out at Samaru, Zaria in the 2022 and 2023 cropping seasons to study the effect of weeding frequencies for the management of flea beetles (Podagrica spp.) on the production and yield of okra (Abelmoschus esculentus L. Moench). A randomized complete block design (RCBD) replicated four times was used to evaluate the four weeding frequencies: no weeding, one weeding, two weeding, three weeding, and four weeding. Data were collected on the number of beetle populations, the number of flowers produced, number of damaged fruits, number of leaves damaged and the weight of the fruits. The results of the present findings demonstrated that, in comparison to other weeding frequency, fruit yield were higher in plots that were weeded four times, while the populations of flea beetles (Podagrica spp.), number of flowers and leaves damaged were significantly (P<0.05) higher in one, two and four weeding compared with no and three weeding frequencies. Fruit damaged weight was considerably (P≤0.05) decreased in two and three weeding. Thus, as part of integrated pest management (IPM) techniques to optimize flea beetle control, this study highlighted the significance of two and three weeding frequencies

Influence of Sphagnum harvesting on arthropod fauna and vegetation with a focus on beetles (Coleoptera) and ants (Hymenoptera: Formicidae)

The harvesting of living peat moss (Sphagnum spec.) for various industrial applications has become increasingly prevalent. The harvesting process involves manual or mechanical extraction of Sphagnum fragments with minor to significant alterations of the habitats. This study investigates the impact of Sphagnum harvesting on arthropod fauna and vegetation structure at two donor sites with small-scale Sphagnum harvest in northwestern Germany. In the first year after the harvest, comparative surveys were carried out between harvested and unharvested reference areas. Arthropods living in and on the upper Sphagnum layer were studied by manually extracting quadrat samples. Vegetation surveys focused on the vascular plant composition and Sphagnum layer thickness as key habitat parameters. Results indicate no substantial effects on the total numbers for most arthropod orders. In contrast, the frequency of ant workers and the number of ant nests were considerably lower in harvested areas compared to reference areas. Vegetation analysis revealed that the shortening of the Sphagnum hummocks led to a homogenization of the vegetation structure and alterations in species composition in favor of moisture-loving species. Although no significant effects on total beetle populations were observed, the abundance of bog generalists and specialists was significantly reduced in harvest areas. Certain species displayed preferences for harvested or reference areas. Future harvesting practices should consider preserving vulnerable arthropod species and restricting harvesting to a small scale to mitigate adverse effects on bog ecosystems.

Testing metabolic cold adaptation and the climatic variability hypothesis in two latitudinally distant populations of a supratidal water beetle

Temperature significantly impacts ectotherm physiology, with thermal tolerance and metabolic traits typically varying with latitude across species ranges. The drivers of this variation remain unclear, however, despite obvious consequences for population persistence and conservation in the face of ongoing global change. This study explored local adaptation and phenotypic plasticity of metabolic rates and thermal limits in the supratidal rockpool beetle Ochthebius lejolisii. Using populations from localities at different ends of the species range that experience contrasting thermal variability, we simultaneously tested two of the major paradigms of spatial physiological ecology: metabolic cold adaptation (MCA) and the climatic variability hypothesis (CVH). Reciprocal acclimation was conducted under spring temperature regimes of both localities, incorporating local diurnal variation. Metabolic rates were measured by closed respirometry, and thermal tolerance limits estimated through thermography. In line with MCA, the higher-latitude population (colder climate) showed higher metabolic rates and temperature coefficients (Q10s) at lower temperatures than the lower-latitude population. As predicted by the CVH, the lower-latitude population (more variable climate) showed higher upper thermal tolerance but only the higher-latitude population was able to acclimate upper thermal limits. This result suggests trade-offs between physiological thermal limits and thermal plasticity in this species. A limited acclimation capacity could make populations on Mediterranean coasts especially vulnerable in the face of projected increases in extreme temperatures under ongoing climate change.

Comparison of ethanol-baited trap designs for ambrosia beetles in orchards in the eastern United States.

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are among the most devastating pests of orchards, nurseries, and forests. Improving trap design and ethanol lures for capturing ambrosia beetles is necessary to develop effective monitoring and management strategies. In this 2-year study, we assessed 4 trap designs and 3 commercially formulated ethanol lures to refine trapping methods tailored for orchard environments in the eastern United States. Our investigation included orchards in 2 regions, Georgia (pecan orchards) and New York (apple orchards), targeting major ambrosia beetle (Coleoptera: Curculionidae) pest species such as Xylosandrus crassiusculus (Motschulsky), X. compactus (Eichhoff), X. germanus (Blandford), and Anisandrus maiche (Stark). Among the trap designs evaluated, clear sticky cards were most effective for capturing ambrosia beetles across orchard locations. Notably, in Georgia, sticky cards paired with specific low-release ethanol lures demonstrated enhanced capture of X. crassiusculus and X. compactus, 2 key ambrosia beetle pests found infesting young pecan trees. Similarly, in New York, sticky cards baited with low-release ethanol lures captured the highest rates of X. germanus and A. maiche, thus indicating its suitability for diverse ambrosia beetle populations. Overall, our study provides practical implications for tailoring trapping protocols to optimize ambrosia beetle management strategies in orchard settings.