Beetle Activity Research Articles

Seasonal activity and phoresy rates of Nitidulid beetles (Coleoptera: Nitidulidae) captured in stands with oak wilt infections in northern Michigan, USA.

Nitidulid beetles (Coleoptera: Nitidulidae), the overland vectors of the Bretziella fagacearum fungus that causes oak wilt, were monitored in infection centers in Quercus rubra stands in northern Michigan, USA using baited, wind-oriented traps for 2 years. First nitidulid captures, accounting for <1.5% of total annual captures, occurred in late April in both years (<50 cumulative degree days [DDs]; base 10°C). A total of 1,188 and 735 beetles representing 19 and 18 species were captured in 2018 (18 traps; 3 sites) and 2019 (16 traps; 4 sites), respectively. Ground traps (1.5 m high) captured more beetles and species than traps on canopy branches of red oaks. Most nitidulids (81-86%) were captured in May and June, but frequent precipitation and cool spring temperatures extended activity into early July in 2019. In 2018, 336 beetles representing 12 species were screened for B. fagacearum spores, but only 20 beetles from 4 species bore viable spores. Mycelial mats on red oaks killed were 4-fold more abundant in 2019 than in 2018. Of the 225 beetles screened in 2019, 56 beetles representing 6 species had viable spores. Nearly all (96%) spore-bearing beetles in both years were captured in late May or June. In bimonthly xylem samples collected from healthy trees, large earlywood vessels, presumably more vulnerable to infection than latewood, were present from May to June in 2018 and until early July in 2019. Results are consistent with mid-May to mid-July high-risk periods designated in current state and regional guidelines for oak wilt management.

Budworms, beetles and wildfire: Disturbance interactions influence the likelihood of insect‐caused disturbances at a subcontinental scale

Abstract Irruptive forest insects are a leading biotic disturbance across temperate and boreal forests. Outbreaks of forest insects are becoming more frequent and extensive due to anthropogenic drivers (e.g. climate and land‐use), perhaps increasing the likelihood that forests will experience multiple insect‐caused disturbances. Across the fire‐prone Douglas‐fir forests of western North America, recent outbreaks of the western spruce budworm and Douglas‐fir beetle have impacted large expanses of forests, with a higher degree of overlap than expected in some ecoregions. Outbreaks of both insects are positively related to host availability and exhibit density‐dependent population dynamics that are affected by climate and weather. Here, we leverage data from aerial detection surveys, estimates of host availability, climate and weather, and categorized fire severity to describe the spatial overlap between western spruce budworm and Douglas‐fir beetle and assess: (1) how climate and host availability influence the biogeography of outbreaks; (2) how weather incites outbreaks; and finally, (3) how prior disturbances (fire and biotic) affect the subsequent outbreak likelihood of western spruce budworm and Douglas‐fir beetle. Models demonstrate that western spruce budworm and Douglas‐fir beetle share similar predisposing drivers of outbreaks. Outbreaks of both insects were more likely to occur following warm weather, but only beetle outbreaks were more likely following drought. When controlling for differences in outbreak distribution and inciting factors, results indicate that both prior fire and interspecific disturbance altered the likelihood of subsequent insect‐caused disturbance. Specifically, Douglas‐fir beetle outbreaks were more likely to occur for several years following low severity fire, but less likely otherwise. Prior defoliation, especially longer duration defoliation, increased the likelihood of beetle outbreak within stands and across the landscape. On the contrary, western spruce budworm outbreaks were less likely to occur following fire, while prior beetle activity dampened budworm outbreak likelihood for several years, and then eventually increased outbreak likelihood. Synthesis: Biotic–biotic disturbance interactions have the potential to amplify the incidence of insect‐caused disturbance across subcontinental scales. Our findings highlight the need for future work on mechanistic linkages between biotic disturbance agents as well as the ramifications for forest trajectories and function.

Spruce bark beetle phenological modelling and drought risk within framework of TANABBO II model

Global warming plays a major role in the disruption of forest ecosystems by bark beetle outbreaks. Decreasing precipitation and more frequent droughts create the conditions for water stress in trees. The Eurasian spruce bark beetle (Ips typographus L.) is more dangerous for Norway spruce (Picea abies (L.) Karst.) forests in Central Europe under these conditions, because even healthy trees under water stress have a lower probability of survival during massive spruce bark beetle outbreaks. This critical issue highlights the importance of targeted research and intervention strategies in affected regions; hence, this study has a focus on the Horní Planá region in Central Europe, which is managed by the Military Forests and Farms of the Czech Republic (VLS).The study presents the results of the drought risk assessment of the operational part of TANABBO II and its validation. TANABBO is a high spatial resolution risk assessment tool for spruce bark beetle infestation in Central European forests, incorporating 30 m spatial resolution and extensive meteorological data, which outperforms existing models in its ability to accurately predict bark beetle activity based on the PHENIPS phenological model. The operational part integrates environmental factors such as global radiation, temperature, precipitation and, in particular, water stress, which is assessed by using a transpiration deficit. The drought risk assessment included the calculation of Drought Indices (DI) and Cumulative Transpiration Deficit Indices (CTDI) on a daily basis, and the estimation of spruce bark beetle swarming time using the PHENIPS model. The risk assessment was validated by comparing it with the number of bark beetles caught in traps and the value of the drought index. Generalised additive models (GAM) were used for validation, with the most effective models incorporating the CTDI. The model with the highest predictive accuracy achieved an adjusted R-squared value of 0.478. The study highlights the critical role of high-resolution environmental data in understanding and managing bark beetle outbreaks, particularly in the context of climate change.

Comparative Efficacy of Organic Mulching and Organic Neem Oil in the Control of spotted and striped cucumber beetles affecting the growth and yield of Cucumber in Uyo, Akwa Ibom State

A research work was undertaken in the University of Uyo Teaching and Research Farm, Main Campus, Uyo, from March to May during the 2023 cropping season to assess the effect of Organic Mulching and Neem Oil in the Control of Cucumber Beetles (spotted “Diabrotica undecimpunctata” and striped “Acalymma vitatum”) affecting the growth and yield of Cucumber (Cucumis sativum, Saira F1 variety). The experiment was laid out in Randomized Complete Block Design (RCBD). The experimental plot consisted of three (3) replicates with 2 treatments: organic mulch, organic Neem oil application and control. An early maturing variety of cucumber “Saira F1” was used as planting material sown in March which lasted till May. Data on insect pest population count, growth and yield parameters were studied and the data obtained were analyzed and subjected to analysis of variance using Fisher`s Least Significant Difference (LSD) at 5% probability level. The results from insect population count parameters revealed that Neem oil at 100ml application rate which recorded 10.50 and 6.00 was significantly effective in managing spotted and striped cucumber beetles respectively compared to organic mulch (3kg) which recorded 47.00 and 14.00 for spotted and striped cucumber beetles and control unit which had 61.00 and 42.00 for spotted and striped cucumber beetles respectively. Neem oil at 100ml application rate was also more effective in improving the growth and yield of cucumber plant compared to organic mulch. Hence, Farmers in Uyo, Akwa Ibom State should employ Neem oil in managing spotted and striped cucumber beetles in cucumber production as this is a promising botanical insecticide to check the activities of field cucumber beetles thereby bringing their destructive activities to a minimum and also improves yield.

Bark beetle-driven community and biogeochemical impacts in forest ecosystems: a review

Abstract Bark beetles are a principal source of tree mortality in conifer forests, with beetle distribution and beetle-associated tree mortality increasing in frequency and extent. While bark beetles are associated with large-scale outbreaks that affect landscape structure, function, and wood quality, they are also drivers of important ecological processes that modify forest ecosystems. Bark beetle activity may affect biogeochemistry and forest decomposition processes by mediating microbial and detrital communities and by facilitating the turnover of deadwood. The turnover of deadwood in bark beetle-attacked forests has important implications for forest biogeochemical cycling, as dead wood releases CO2 into the atmosphere and carbon, nitrogen, and other nutrients into surrounding soils. However, our understanding of how initial physical, chemical, and biotic changes to bark beetle-attacked trees affect the succession of detrital organisms and decomposition of beetle-generated deadwood remains poor. Furthermore, the relationship between woody decomposition and landscape-level changes in biogeochemical processes in forest ecosystems following bark beetle activity is not well unified. This review article bridges this divide and provides an interdisciplinary perspective on tree mortality, ecological succession, and woody decomposition mediated by bark beetles.

Intelligent inspection probe for monitoring bark beetle activities using embedded IoT real-time object detection

Rapid detection and identification of the extent of spruce bark beetle infestation in the field is a necessity for researchers, forest rangers, and tree protection agencies. This paper presents an innovative solution that uses an autonomous multifunctional probe with embedded artificial intelligence. This approach is based on the real-time object detection method, called “first object, more object” (FOMO), which is adapted to the energy-efficient architecture of the ESP32 microcontroller. Neural network algorithms for fast image processing were trained using data sets from various locations in central Europe, which were heavily affected by the bark beetle calamity. The results of the experimental verification of the deployment of this smart probe in the field demonstrate a high level of precision in the detection and identification of the extent of damage.

The Diversity of Forensic Entomofauna Associated With Decaying Chicken Liver in the Tropical Region of Kerala, India.

Forensic entomology To elucidate the time of death based on insect evidence, there are several studies on forensic entomology on life cycles, environmental factors, and feeding habitats of insects. However, there have not been any comprehensive studies on forensic entomology and its usage in forensic inquiry specific to the region, especially Kerala, India. The insect succession on decomposed animal matter plays an important role in estimating minimum postmortem intervals (mPMI). Objective The purpose of the study was tounderstand forensically important insect groups and their role in the decomposition process of dead decayingmatter. The different decomposition stages of a corpse vary in attraction to necrophagous insects and the insect fauna depending on its prevailing conditions of decay. The decomposition is highly dependent on the exposition of animal matter and abiotic and biotic factors acting on it. The main objective of the present investigation was to identify the insect fauna associated with decaying chicken liver. The study also envisages comprising the diversity and abundance of insects between two different treatments of animal matter: in contact with soil and controlled conditions in a clean basin. Method The study was conducted for 45 days (until the total decomposition of the samples in both conditions) during the pre-monsoon months of April to May2022 at Chalikadavu, Muvattupuzha, in the Ernakulam district, Kerala, India. The samples were however kept away from direct sunlight and rain to avoid the direct impact on the orienting fauna. The entomofauna found to be associated with the decaying animal matter was carefully collected from the site and stored in 70% isopropyl alcohol for preservation. The total number of insects was recorded along with the hours of maximum incidence, and samples were stored in plastic vials for further identification. Result In this study, we analyzed the activities of ants, mites, wasps, cockroaches, moths, beetles, and flies during the decomposition of decaying chicken liver. Among these insects, flies and beetles are two important arthropod communities associated with animal matter decomposition. We collected these foraging organisms for morpho-taxonomic identification. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of decaying corpse with special reference to the insect fauna acting on it. Conclusion We got 100 specimens comprising 28 species in 17 families from Blattidae, Coleoptera, Diptera, Hymenoptera, and Lepidoptera. Besides this, we identified two parasitic wasps with their host (dipteran pupa), which is helpful in postmortem interval (PMI) estimation. Our analysis showed an association between decay and the activity of carrion insects. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of a decaying corpse with special reference to the insect fauna acting upon it.

Eucalyptus and spearmint oils inhibit the biological activity of lesser grain borer and red flour beetles

The objective of this investigation was to assess the insecticidal efficacy of essential oils derived from eucalyptus (Eucalyptus camaldulensis) and spearmint (Mentha spicata) against two species of stored-product insects. The process of Clevenger-type water distillation was employed to extract essential oils from two distinct plant species. Subsequently, the insecticidal properties of these oils were evaluated against specimens of the American wheat weevil (Rhyzopertha dominica) and the red flour beetle (Tribolium castaneum), belonging to the Coleoptera: Bostrichidae and Tenebrionidae families, respectively. Eucalyptus oil exhibited the highest level of inhibition of insects’ reproduction. Still, when tested on adults of both types of insects, eucalyptus and spearmint oils were more effective than the control treatment. A complete inhibition of egg-laying activity (100%) was achieved using a 7% concentration of eucalyptus oil. The trials were done within controlled laboratory settings, with a notable absence of tests conducted under authentic operational conditions. Researchers who want to learn more about using essential oils as insecticides in the future should focus on making pesticide formulations that work well in a wide range of production settings.

Ecological engineering in low land rice for brown plant hopper, Nilaparvata lugens (Stål) management.

Rice field bunds and edges can act as near crop habitats, available for planting flowering plants to attract and conserve the natural enemies. We evaluated the effect of ecological engineering on the incidence of Brown Planthopper (BPH), Nilaparvata lugens (Stål)(Hemiptera; Delphacidae) and the abundance of its predators in the rice variety Pusa Basmati-1121. Plots included the oilseed crops viz. sesamum, sunflower and soybean, with plantings of flowering crops marigold, balsam and gaillardia as bund flora around the edges of rice plots. Ecologically engineered plots contained both crops+flowers and resulted in a significantly reduced BPH population per hill in rice plots for 2019 (6.3) and 2020 (9.4) compared to the control plots (9.8 and 14.4). Ecologically engineered plots also witnessed the delayed appearance of BPH during each growing season. Peak BPH populations are lower in the ecologically engineered plots than in the control grounds. Furthermore, the activity of natural enemies, viz., spiders, mirid bugs and rove beetles was the highest in rice fields planted with oilseed crops like sesamum, sunflower and soybean. Olfactory response studies showed that the attraction response of spiders toward sesamum and balsam leaves was more significant than in other crop plants. Rice yield was enhanced in plots planted with crops+flowers during both seasons compared to control plots. Planting of oilseed crops plants such as sesamum, sunflower and soybean with flowering crops such as marigold, balsam and gaillardia as bund flora on the bunds around the main rice field enhanced the natural enemy activity, suppressed the planthopper population, and increased yields. Based on the results, we recommend including ecological engineering techniques as one of the management components in the Integrated Pest Management programme for rice crops.

Dung beetles diversity and their role in nutrient cycling in livestock systems of the dry Chaco

Dung beetles represent one of the main animal groups involved in the cycling of cattle dung, modifying soil physicochemical properties, and reducing parasite incidence. However, their diversity and activity in cattle areas depends on conserving critical resources and conditions, including native vegetative composition, microclimatic and soil conditions. Whereas most previous studies were conducted in humid forests, our objective was to experimentally study the diversity and role of dung beetles in soil nutrient dynamics in native forests and shrub savannas with cattle ranching in the dry Chaco of Argentina. Using pitfall traps, we collected dung beetles in both habitats. In cow exclusions, we buried two plastic containers filled with soil and two kg of fresh cow dung on the surface and covered one with a mosquito net to prevent the access of dung beetles. After three months, we collected soil samples and analyzed nutrient contents and soil structure. Contrary to previous studies, the abundance and richness of dung beetles were higher in savannas than in native forests. In both habitats, the activity of dung beetles strongly increases phosphorous and potassium contents; however, consistent with the higher abundance, this effect was more marked in shrub savannas. In addition, we observed higher contents of total organic carbon, electrical conductivity, and calcium in native forests. Our results emphasize the critical role of dung beetles in maintaining soil quality in the most extended cattle management practices of the dry Chaco. Moreover, our results were opposite to previous studies conducted in humid forests, which could be associated with greater tolerance of native species to extreme microclimate conditions in the dry Chaco.

Traditional prescribed burning of coastal heathland provides niches for xerophilous and sun-loving beetles

In Western Norway, farmers have traditionally used fire as a management tool in coastal heathlands to enhance the fodder quality for livestock. Rotational prescribed burning increases landscape heterogeneity by creating a mosaic of different regeneration stages of heather. Ground beetle (Coleoptera: Carabidae) responses to fire in traditionally managed coastal heathland have already been studied, but less is known about other beetle groups in this system. We compared the beetle activity between patches of mature and recently burnt heath, by looking at diversity indices, species composition and ecological preferences and traits. Contrary to previous studies, we did not find an increase in beta diversity after disturbance, but we found that prescribed burning offers micro-environmental conditions which enhanced the activity of sun-loving and xerophilous species. We also identified new indicator species for both mature and pioneer heath in five beetle families: Carabidae, Staphylinidae, Curculionidae, Leiodidae, and Scirtidae. Rotational prescribed burning was confirmed to be an efficient conservation tool for specialists without affecting the overall diversity of the site. We recommend the use of several taxa, ecological preferences and traits to assess the impact of prescribed burning and to monitor the condition of traditionally managed coastal heathlands.

Ground-dwelling arthropods as biodiversity indicators in maize agroecosystems of Northern Italy

Reliable monitoring of arthropod diversity in a given agroecosystem is essential for the conservation of the related ecosystem services, such as biological control. The often daunting complexity of arthropod collection and identification, however, highlights the need for surrogate taxa that can be easily sampled and be representative of a number of other taxa in term of diversity, general community features and specific composition.In this study, we used pitfall traps to sample three ground-dwelling arthropod taxa important as biocontrol agents (ground beetles, rove beetles and spiders) in 9 conventionally managed maize agroecosystems of Northern Italy over the course of two years, with the goal of characterizing their assemblages and evaluating their reciprocal potential as indicators of activity density, species richness, community turnover and species co-occurrence.Although dominated by few generalist species, sampled arthropod communities were relatively species-rich, and included the first Italian record of the spider Zelotes metellus (Roewer) (Araneae: Gnaphosidae). Ground beetles as a group were confirmed as promising indicators for the species richness and community composition turnover of rove beetles and spiders. Additionally, several abundant arthropod species acted as indicators of the species richness of their respective groups, and the ground beetle Pterostichus macer (Marsham) also worked as an indicator of overall rove beetle activity density. While the co-occurrence of individual arthropod species was limited for the studied taxa, a few species such as the ground beetle Parophonus maculicornis (Duftschmid) did show promise as species-specific bioindicators. Our results could be useful in improving the monitoring and management of these important natural enemies in maize-growing regions.

Multi-trophic occupancy modeling connects temporal dynamics of woodpeckers and beetle sign following fire.

In conifer forests of western North America, wildlife populations can change rapidly in the decade following wildfire as trees die and animals respond to concomitant resource pulses that occur across multiple trophic levels. In particular, black-backed woodpeckers (Picoides arcticus) show predictable temporal increases then declines following fire; this trajectory is widely believed to be a response to the woodpeckers' main prey, woodboring beetle larvae of the families Buprestidae and Cerambycidae, but we lack understanding of how abundances of these predators and prey may be associated in time or space. Here, we pair woodpecker surveys over 10 years with surveys of woodboring beetle sign and activity, collected at 128 survey plots across 22 recent fires, to ask whether accumulated beetle sign indicates current or past black-backed woodpecker occurrence, and whether that relationship is mediated by the number of years since fire. We test this relationship using an integrative multi-trophic occupancy model. Our results demonstrate that woodboring beetle sign is a positive indicator of woodpecker presence 1-3 years following fire, an uninformative indicator from 4-6 years after fire, and a negative indicator beginning 7 years following fire. Woodboring beetle activity, itself, is temporally variable and dependent on tree species composition, with beetle sign generally accumulating over time, particularly in stands with diverse tree communities, but decreasing over time in Pinus-dominated stands where faster bark decay rates lead to brief pulses of beetle activity followed by rapid degradation of tree substrate and accumulated beetle sign. Altogether, the strong connections of woodpecker occurrence to beetle activity support prior hypotheses of how multi-trophic interactions govern rapid temporal dynamics of primary and secondary consumers in burned forests. While our results indicate that beetle sign is, at best, a rapidly shifting and potentially misleading measure of woodpecker occurrence, the better we understand the interacting mechanisms underlying temporally dynamic systems, the more successfully we will be able to predict the outcomes of management actions.

The role of dung beetle species in nitrous oxide emission, ammonia volatilization, and nutrient cycling

This study evaluated the role of dung beetle species alone or associated under different species on nitrous oxide (N2O) emission, ammonia volatilization, and the performance of pearl millet [Pennisetum glaucum (L.)]. There were seven treatments, including two controls (soil and soil + dung without beetles), single species of Onthophagus taurus [Shreber, 1759] (1), Digitonthophagus gazella [Fabricius, 1787] (2), or Phanaeus vindex [MacLeay, 1819] (3); and their assemblages (1 + 2 and 1 + 2 + 3). Nitrous oxide emission was estimated for 24 days, when pearl millet was planted in sequence to assess growth, nitrogen yield (NY), and dung beetle activity. Dung beetle species presented greater N2O flow of dung on the 6th day (80 g N2O-N ha−1 day−1) compared to soil and dung (2.6 g N2O-N ha−1 day−1). Ammonia emissions varied with the presence of dung beetles (P < 0.05), and D. gazella had less NH3−N on days 1, 6, and 12 with averages of 2061, 1526, and 1048 g ha−1 day−1, respectively. The soil N content increased with dung + beetle application. Dung application affected pearl millet herbage accumulation (HA) regardless of dung beetle presence, and averages ranged from 5 to 8 g DM bucket−1. A PCA analysis was applied to analyze variation and correlation to each variable, but it indicated a low principal component explanation (less than 80%), not enough to explain the variation in findings. Despite the greater dung removal, the largest species, P. vindex and their species combination, need to be more studied to get a better understanding about their contribution on greenhouse gases. The presence of dung beetles prior to planting improved pearl millet production by enhancing N cycling, although assemblages with the three beetle species enhanced N losses to the environment via denitrification.

Exposure to artificial light at night mediates the locomotion activity and oviposition capacity of Dastarcus helophoroides (Fairmaire).

Light entrains the endogenous circadian clocks of organisms to synchronize their behavioral and physiological rhythms with the natural photoperiod. The presence of artificial light at night disrupts these photoperiodic cues and is currently considered to be a major threat to key fitness-related behaviors, including sleep disruption and physiological stress. Research on the ecological influence of forest pest and their natural enemies is lacking. The wood-boring insects significantly damage forest and urban forest ecosystem functions. The parasitic beetles, Dastarcus helophoroides is an important natural enemy of wood-boring insects, especially those in the Cerambycidae family. However, the effect of artificial light at night on the locomotor rhythms and oviposition capacity of D. helophoroides has received little attention. To address this gap, diel changes in the locomotor activity and number of eggs laid by female D. helophoroides was analyzed under different light-dark (LD) cycles and temperatures. The results showed that the 24-h rhythmic of locomotor activity in these beetles was elevated in darkness and reduced under illumination, indicating that they are nocturnal insects. This activity has two major peaks, the evening (1-8h after lights off) and morning (3.5-12.5h after lights off) components, reflecting that light mediate regular changes in locomotor activity. Moreover, the circadian rhythms and active percentage were influenced by the illumination duration and temperature, especially constant light and 40°C. Females laid more eggs under the 16L: 8 D cycles at 30°C than under the other combinations of photoperiod (including constant light and darkness) and temperature. Finally, the potential influence of exposure to four ecologically relevant intensities of artificial light at night (0, 1, 10 or 100 lx) on oviposition capacity was studied. The results showed that lifetime exposure to bright artificial light (1-100 lx) at night decreased the number of eggs laid relative to those laid with no lighting at night. These results demonstrate that chronic exposure to bright artificial light at night may influence the locomotor activity and oviposition capacity of this parasitic beetle.

Dung Beetle Activity Is Soil-Type-Dependent and Modulates Pasture Growth and Associated Soil Microbiome

The introduction of numerous exotic dung beetles across southern Australia in regions where native dung beetles are not generally efficient in processing livestock dung has resulted in significant reductions in the quantity of such dung on the soil surface in recent years. However, the direct impacts of such ecosystem services on pasture quality and soil nutrient mobility have not yet been investigated in the Riverina region of New South Wales (NSW), an area recognised for prime cattle and sheep production in Australia. Utilising 48 soil columns for lysimetry, we quantified the impact of a common introduced dung beetle (Bubas bison) in this region on water quality after permeation through four different soil types sown to winter annual pastures. Dung beetle treatments included dung plus dung beetles, dung alone and no dung beetles, and no dung and no beetles as a control. Dung beetles and soil type impacted on the performance of improved overseeded annual pastures as measured by biomass accumulation over a four-month growing season. The four soil types, namely, Chromosol, Kandosol, Rudosol, and Vertosol, differed considerably with respect to their water-holding capacity and nutrient profiles, as assessed by initial soil testing and soil leachate evaluation following rainfall plus simulated rainfall events. The concentration of Escherichia coli resulting from cattle dung, cattle dung plus beetles, and the control soils without dung or beetles was assessed in collected leachates over a three-month period. E. coli numbers were significantly increased following B. bison activity, when compared to the dung-only and control treatments. Evaluation of the soil microbiome, by assessing genomic DNA in soils sampled 10 cm below the soil surface where dung beetles remained active following tunnelling, revealed significant differences among soil types with respect to bacterial and fungal communities. Within each soil type, dung beetle activity impacted the fungal community structure, but not the bacterial community. Pasture performance as assessed by biomass accumulation was significantly improved following dung beetle activity in later stages of pasture growth, while E. coli numbers and total coliforms appeared unaffected by beetle presence.

Ecological Role of &lt;i&gt;Onthophagus taurus&lt;/i&gt; (Schreber) in Soil Nutrient Mobilization

Dung beetles play a major role in the pasture ecosystem. The manure recycling activity of dung beetles is linked to their tunneling behavior. The present study was designed to analyze the tunnel pattern and nutrient mobilization by dung beetles, Onthophagus taurus (Schereber, 1759) in different soil types. A simple type of tunnel pattern was observed in all the four types of soil after 30th day of their introduction (10 pairs of male and female) into the experimental setup. However, the maximum number of tunnels was observed in the sandy and sandy clay loam (no. of openings - 15), followed by loamy soil (no. of openings -13). The physical (texture, water holding capacity, porosity, moisture content) and chemical parameters (pH and nutrients) of all the four types of soils were evaluated. Soil texture analysis revealed the texture to be of sandy (yellow soil), sandy clay loam (red and black soil), and loamy sand (brown soil) types. Water holding capacity and the soil porosity were recorded highest in the sandy soil, whereas moisture content was found maximum in the sandy clay loam. Soil nutrient analysis illustrated a significant increase in the amount of nitrogen (N), phosphorus (P), calcium (Ca), sulfur (S), sodium (Na), potassium (K), organic carbon and organic matter. Thus, the present study confirms that tunneling activity of O. taurus enhances the soil nutrients by carrying out dung decomposition.

Diurnal and seasonal rhythm of the melon ladybird - Epilachna chreysomelina (Coleoptera, Coccinellidae) activity in the conditions of the Kashkadarya region of Uzbekistan

The paper describes that the first signs of beetle movement after night rest in the month of May occur at 8 am at an air temperature of about 200C. Increasing the temperature to 22-290C tends to increase their mobility. By 11 a.m., when the air temperature reached 340C, almost all the beetles went into the shade, into the lower part of the plants, where they remained immobile until almost 4 p.m. After 17 h. the air temperature dropped to 330С, by 20:00 to 200С. By this time, only a small part of the beetles remained active. In summer, the motor activity of beetles intensifies at 8-10 am, when the air temperature rises to 340C. From 11 a.m. to 6 p.m. at a temperature of 34-420C, humidity 34-40%, the beetles were placed in the shade and were inactive. In autumn, after night cooling, the air temperature increased later and the movement of beetles began at 11 am At noon hours (between 12-4 pm) at an air temperature of 20-250C. and humidity 55-60%, beetle activity was maximum. In summer, beetles actively feed in the morning (from 8-9 a.m.) and evening (from 19 to 22 p.m.) hours, when the air temperature was 26-330C. In the middle of the day (13-16 hours) and at night (3-5 hours), their feeding activity is somewhat reduced. The intensity of beetle feeding in the autumn months increases from 9 a.m. and reaches a maximum by 11-13 a.m., and after 5 p.m. it begins to decrease and almost stops at 9 p.m. in the evening.

Effects of dung beetle activity on tropical forest plants

Dung beetles are recognized as providers of important ecosystem functions, most of which are derived from the removal of vertebrate dung from the soil surface. These insects occur in nearly all terrestrial biomes but are most diverse in the humid tropics. Several of the ecological functions attributed to dung beetles are related to their direct and indirect interactions with plants. Among these functions, the secondary dispersal of seeds defecated by mammals has received the most attention in tropical forests. Nonetheless, while several aspects of secondary seed dispersal by dung beetles are relatively well understood, others remain understudied or have not been addressed at all. Thus, a broad generalization about the effects of secondary seed dispersal by dung beetles on plant fitness remains somewhat elusive. Furthermore, other effects of dung beetle activity on tropical plants have received very little attention. A few studies have shown that through their behaviors of dung burial and soil-excavation, dung beetles can shape seed bank structure and dynamics. Also, though numerous greenhouse studies and field experiments in agricultural lands and temperate grasslands have shown that dung beetle activity increases plant nutrient uptake and yield, it is uncertain whether such effects are common in tropical forests. Here, we review and synthesize our current knowledge on how dung beetles affect tropical forest plants by dispersing defecated seeds, shaping the structure and dynamics of seed banks, and influencing the performance of understory seedlings. We focus on the Neotropics, where most studies on the effects of dung beetles on tropical forest plants have been carried out, but we also show results from other regions and biomes, to present a more general picture of these beetle-plant interactions. Throughout the review we emphasize aspects that need more research to allow generalizations and point out those questions that remain unanswered. We hope that this review will stimulate more research about the fascinating interactions between dung beetles and plants in tropical ecosystems.

Influence of ground beetles (Carabidae) as biological agent to control of the Mediterranean fruit fly pupae, Ceratitis capitata, in Iranian citrus orchards

• High diversity and density of Carabidae observed with eliminated pesticide spray. • Instead pesticide, mineral oil spray led conserving the carabids species. • Seasonal density fluctuation of Carabidae was observed, increasing in spring. • Highest population of Carabidae with the peak of fruit fly damage in September. • H. rufipes, B. karelinii and Pterostichus macer were the most voracious predators. Damage by Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in the northern Iranian citrus orchards has been led to spray by different chemical pesticides. The present study was conducted in the citrus orchard in Mazandaran province of Iran where with the exception of mineral oil treatments for scale insects, had not been sprayed with synthetic insecticides for six years. The purpose of this study was initially to investigate faun and seasonal activity of predaceous ground carabid beetles in the citrus orchards. Additionally, their role as predators of Ceratitis capitata (Wiedemann) pupae was evaluated under laboratory and field conditions. Predation in laboratory was evaluated by no choice feeding experiments while predation under field conditions was evaluated by molecular detection of the pest DNA in the gut contents of field-collected Carabids. A total of 3,437 beetles of ten carabid species were collected from a non-chemical treatment citrus orchard. The results of the seasonal density fluctuation indicated increasing population in spring reaching the highest in September, simultaneously with the peak of fruit fly damage, and thereafter decreasing during winter when the pest was overwintering. However, three species, Harpalus rufipes, Broscus karelinii and Brachinus brevicollis were most abundant in the field collection but the results of no-choice experiments in the laboratory indicated H. rufipes, B. karelinii and Pterostichus macer were the most voracious predators on pupae. Results of gut content analysis of the voracious species indicated the positive testing for pest DNA in 79.16 % of H. rufipes , 76.92% of B. karelinii and 75% of P. macer of analyzed beetles. The results of the study strongly indicated that in citrus orchards where intensive spraying is eliminated, natural enemies such as Carabid beetles could play an important role in reducing pests such as medfly.