Beetle Populations Research Articles

Diseases and Pests Harmful to Honeybees (Apis spp.) and Their Management Tactics: A Review

Honeybees (Apis spp.) play a vital role in pollination and contribute significantly to global agriculture. However, the health and survival of honeybee colonies are threatened by a range of harmful insect pests and diseases. This review provides an overview of the major pests and diseases that impact honeybee colonies and explores the diverse management tactics employed to mitigate their effects. The primary focus is on key pests such as the Varroa mite (Varroa destructor), which inflicts considerable damage by parasitizing adult bees and their brood, facilitating the transmission of debilitating viruses. Management strategies for Varroa mites encompass chemical treatments, integrated pest management (IPM) approaches, and organic treatments to curtail mite populations and prevent colony collapse. Another significant threat discussed is the small hive beetle (Aethina tumida), a beetle species that disrupts hives by laying eggs in comb and consuming stored resources. Hive manipulation, traps, and chemical controls are among the tactics utilized to control small hive beetle populations and mitigate their impact. The review also addresses wax moths (Galleria mellonella and Achroia grisella), which target hive comb, potentially causing comb destruction and honey fermentation. Hive maintenance, freezing, and pheromone traps are outlined as effective strategies to combat wax moth infestations. Additionally, the review covers Nosema infections (Nosema apis and Nosema ceranae), and microsporidian parasites that compromise adult bee health by weakening immune systems and reducing foraging efficiency. Hive hygiene, medications, and genetic selection are explored as methods to manage Nosema infections and bolster colony resilience. To effectively manage these harmful pests and diseases, a holistic and integrated approach is recommended. Beekeepers are encouraged to remain informed about the latest research findings and implement appropriate measures, considering local conditions and sustainable beekeeping practices. By combining scientific knowledge with practical application, the resilience of honeybee colonies can be enhanced, ensuring the vital role they play in pollination and global food security.

Seasonal Incidence of Insect-Pests of Field Pea

During both seasons, aphid incidence peaked at 38.40 aphids/10cm shoot at the 5th SMW and 40.51 aphids/10cm shoot at the 4th SMW, respectively. While the activity of leafhoppers attained the peak of 14.20 leafhoppers/3 leaves during 7th SMW and 13.20 leafhoppers/3 leaves during 6th SMW during both seasons, respectively. During 2019-20, the whitefly population initiated at 5th WAS and persisted until the 13th WAS (1.44 to 11.28 whiteflies/3 leaves), whereas, in 2020-21, the population began in the 6th WAS and peaked during 12th WAS (12.21 whiteflies/3 leaves). Pod borer population started in 5th WAS and peaked (1.34 larvae/plant) in 10th WAS during 2019-20; in 2020-21, the population peaked (1.12 larvae/plant) during 11th WAS. The ladybird beetle population was active from 6th to 13th WAS and reached a peak (2.86 beetles/plant) during the 10th WAS in 2019-20. During the second season, the population of ladybird beetles started in the 7th WAS and peaked at 2.30 beetles/plant in 10th WAS. The spider appeared on the crop on the 5th WAS and remained active until 14th WAS, with the peak activity (0.34 and 0.30 spider/plant) reported during 6th SMW in both seasons. Significantly negative correlation was seen between evening relative humidity and leafhopper population during both seasons. Other insect-pests (aphid, leafhopper, whitefly and H. armigera) showed non significant impact of weather parameters during both seasons. Whereas, H. armigera larvae had positive correlation with bright sunshine hours and wind velocity during both seasons. Ladybird beetle showed highly significant and positive correlation with aphid, leafhopper and whitefly population during both seasons. Spider showed significant and positive correlation with aphid, leafhopper and whitefly population in both seasons.

Coupling Mountain Pine Beetle and Forest Population Dynamics Predicts Transient Outbreaks that are Likely to Increase in Number with Climate Change.

Mountain pine beetle (MPB) in Canada have spread well beyond their historical range. Accurate modelling of the long-term dynamics of MPB is critical for assessing the risk of further expansion and informing management strategies, particularly in the context of climate change and variable forest resilience. Most previous models have focused on capturing a single outbreak without tree replacement. While these models are useful for understanding MPB biology and outbreak dynamics, they cannot accurately model long-term forest dynamics. Past models that incorporate forest growth tend to simplify beetle dynamics. We present a new model that couples forest growth to MPB population dynamics and accurately captures key aspects of MPB biology, including a threshold for the number of beetles needed to overcome tree defenses and beetle aggregation that facilitates mass attacks. These mechanisms lead to a demographic Allee effect, which is known to be important in beetle population dynamics. We show that as forest resilience decreases, a fold bifurcation emerges and there is a stable fixed point with a non-zero MPB population. We derive conditions for the existence of this equilibrium. We then simulate biologically relevant scenarios and show that the beetle population approaches this equilibrium with transient boom and bust cycles with period related to the time of forest recovery. As forest resilience decreases, the Allee threshold also decreases. Thus, if host resilience decreases under climate change, for example under increased stress from drought, then the lower Allee threshold makes transient outbreaks more likely to occur in the future.

CLIMATIC FACTORS CAN DIFFERENTLY AFFECT BODY SIZE IN CLOSELY RELATED SPECIES (THE CASE STUDY IN GROUND BEETLES)

The study of body size variation in the altitudinal gradient showed the presence of shifts in the morphometric characteristics of ground beetle populations under the influence of bioclimatic factors. Ground beetles were collected on the Barguzinsky Ridge (Russia, Buryatia) in eight characteristic biotopes in four high-altitude sections: on the coast of Lake Baikal, low, middle and high mountains (458-1667 m above sea level). At each site in 2004–2017, we carried out a quantitative account of ground beetles and recorded the main climatic parameters using thermochrons, sedimentary cylinders, soil thermometers, and a snow gauge. We took two common species – Carabus odoratus and Pterostichus montanus (2200 specimens) for morphometric analysis. The six features of the body organs – the length and width of the elytra, the length and width of the pronotum, and the length of the head and distance between the eyes were measured. Using linear modeling, we investigated how climatic variables affected body size in the studied species. Comparing the reaction of the two species to hydroclimatic parameters, we noted that the reaction was directly opposite to temperature indicators, and the similar to factors that depend on humidity. The higher was the soil temperature at a 5 cm depth, the greater was the length of the elytra, pronotum, and head in C. odoratus, but the same characters were smaller in P. montanus. High population density led to body size decrease in C. odoratus, but P. montanus responded in lesser degree. By genus, C. odoratus turned out to be more sensitive to changes in bioclimatic factors.

Evolution of horn length and lifting strength in the Japanese rhinoceros beetle Trypoxylus dichotomus

What limits the size of nature's most extreme structures? For weapons like beetle horns, one possibility is a tradeoff associated with mechanical levers: as the output arm of the lever system-the beetle horn-gets longer, it also gets weaker. This "paradox of the weakening combatant" could offset reproductive advantages of additional increases in weapon size. However, in contemporary populations of most heavily weaponed species, males with the longest weapons also tend to be the strongest, presumably because selection drove the evolution of compensatory changes to these lever systems that ameliorated the force reductions of increased weapon size. Therefore, we test for biomechanical limits by reconstructing the stages of weapon evolution, exploring whether initial increases in weapon length first led to reductions in weapon force generation that were later ameliorated through the evolution of mechanisms of mechanical compensation. We describe phylogeographic relationships among populations of a rhinoceros beetle and show that the "pitchfork" shaped head horn likely increased in length independently in the northern and southern radiations of beetles. Both increases in horn length were associated with dramatic reductions to horn lifting strength-compelling evidence for the paradox of the weakening combatant-and these initial reductions to horn strength were later ameliorated in some populations through reductions to horn length or through increases in head height (the input arm for the horn lever system). Our results reveal an exciting geographic mosaic of weapon size, weapon force, and mechanical compensation, shedding light on larger questions pertaining to the evolution of extreme structures.

Questioning the monophyly of Anthroherponina (Coleoptera: Leiodidae: Cholevinae: Leptodirini) and description of three new, ecologically ultraspecialized subterranean species

Abstract The beetle subtribe Anthroherponina (Coleoptera: Leiodidae), including also ecologically specialized and semi-aquatic hygropetricolous genera, presents one of the most illustrative examples of morphological variability in cave-adapted animals. However, phylogenetic relations within the tribe remain dubious. Recent exploration of deep-phreatic caves of the Western Balkans Dinaric Karst enabled us to collect all known Anthroherponina genera and access new populations of hygropetricolous beetles, representatives of the iconic Hadesia and elusive Nauticiella. We studied the taxonomic structure of newly collected semi-aquatic beetle populations by using traditional morphology and deploying uni- and multilocus molecular species delimitation. In addition, we tested the monophyly of the subtribe Anthroherponina and set the group’s evolutionary development into a palaeogeographic context by reconstructing a multilocus calibrated phylogeny. As a result, three new species of specialized semi-aquatic beetles are described. The morphologically based monophyly of Anthroherponina was shown to be an artefact of evolutionary convergences, while the evolutionary development of the monophylum seems to be paired with the orogeny of the Dinarides. Finally, the new results raise more questions about our understanding of evolution in subterranean beetles and their adaptation to special ecological niches.

Evaluation of the phenotypic polymorphism of the pattern of Leptinotarsa decemlineata Say pronotum in the conditions of Kamianka-Buzka city (Lviv Oblast)

Aim. The Colorado potato beetle population is characterized by a high degree of polymorphism. This provides a high level of adaptability to the most diverse distribution conditions. The aim is to the study of the variability of the pattern of Leptinotarsa decemlineata pronotum in June 2021 and June 2022. Methods. The analysis of the phenotypic variability of L. decemlineata population of Kamianka-Buzka city based on studying the presence or absence of certain phens, their number and placement according to Tauer method. Results. 22 variations of phens belonging to A, B, C, D, E, G, K, L, M, P groups were found. The dominant were phens of A, B, C, D, E, F groups. The most variable were the phens of A and E groups. The phenotypic structure of the colorado beetle population was determined according to Kohmaniuk’s classification. It was found that the dominant morphs in 2021 and 2022 were U (42 % and 27 %), UP (13 % and 18 %) and V (23 % and 21 %), respectively. Conclusions. The analysis of the frequency of phenoforms according to the Fasulati method showed that in the population of 2021 and 2022, phenoforms 3, 6 and 9 were dominant. They form the basis of the population and ensure the resistance of the population to the insecticides. The study of the intrapopulation diversity indicates an unbalanced population structure of L. decemlineata.

Power Transmission Network Optimization Strategy Based on Random Fractal Beetle Antenna Algorithm

In order to optimize the performance of the transmission network (TN), this paper introduces the random fractal search algorithm based on the beetle antenna search algorithm, thus proposing the random fractal beetle antenna algorithm (SFBA). The main work of this research is as follows: (1) in the beetle antenna search algorithm, this study used a population of beetles and introduced elite members of the population in order to make the algorithm more stable and to some extent improve the accuracy of its answers. (2) Utilizing the elite reverse learning method and the leader’s multilearning strategy for elites helps to strike a balance between the global exploration and local development of the algorithm. This strategy also further improves the ability of the algorithm to find the optimal solution. (3) Experiments on real experimental data show that the SFBA algorithm proposed in this paper is effective in improving TN performance. In summary, the research content of this paper provides a good reference value for the performance optimization of TN in actual production.

Dung beetle optimization algorithm based on quantum computing and multi-strategy fusion for solving engineering problems

The Dung beetle optimization algorithm is a kind of group intelligence optimization algorithm proposed by Jiankai Xue in 2022, which has the characteristics of strong optimization-seeking ability and fast convergence but suffers from the defect of easily falling into local optimum at the late stage of optimization-seeking as other group intelligence optimization algorithms. To address this problem, this paper proposes a dung beetle search algorithm (QHDBO) based on quantum computing and a multi-strategy hybrid. The good point set strategy is used to initialize the initial population of dung beetles . That makes the initial population more evenly distributed, and reduces the likelihood of the algorithm falling into a local optimum solution. The convergence factor and dynamic balance between the number of Spawning and foraging dung beetles is proposed. That allows the algorithm to focus on the global search in the early stages and local exploration in the later stages. The quantum computing based t-distribution variation strategy is used to variate the optimal global solution, that prevents the algorithm from falling into a local optimum. To verify the performance of the QHDBO algorithm, this paper compares QHDBO with six other swarm intelligence algorithms through 37 test functions and practical engineering application problems. The experimental results show that the improved dung beetle optimization algorithm significantly improves convergence speed and optimization accuracy and has good robustness.

Multi-locus genomic signatures of local adaptation to snow across the landscape in California populations of a willow leaf beetle.

Organisms living in mountains contend with extreme climatic conditions, including short growing seasons and long winters with extensive snow cover. Anthropogenic climate change is driving unprecedented, rapid warming of montane regions across the globe, resulting in reduced winter snowpack. Loss of snow as a thermal buffer may have serious consequences for animals overwintering in soil, yet little is known about how variability in snowpack acts as a selective agent in montane ecosystems. Here, we examine genomic variation in California populations of the leaf beetle Chrysomela aeneicollis, an emerging natural model system for understanding how organisms respond to climate change. We used a genotype-environment association approach to identify genomic signatures of local adaptation to microclimate in populations from three montane regions with variable snowpack and a coastal region with no snow. We found that both winter-associated environmental variation and geographical distance contribute to overall genomic variation across the landscape. We identified non-synonymous variation in novel candidate loci associated with cytoskeletal function, ion transport and membrane stability, cellular processes associated with cold tolerance in other insects. These findings provide intriguing evidence that variation in snowpack imposes selective gradients in montane ecosystems.

Climate-driven tree growth and mortality in the Black Forest, Germany-Long-term observations.

Episodic tree mortality can be caused by various reasons. This study describes climate-driven tree mortality and tree growth in the Black Forest mountain range in Germany. It is based on a 68-year consistent data series describing the annual mortality of all trees growing in a forest area of almost 250 thousand ha. The study excludes mortality caused by storm, snow and ice, and fire. The sequence of the remaining mortality, the so-called "desiccated trees," is analyzed and compared with the sequence of the climatic water balance during the growing season and the annual radial growth of Norway spruce in the Black Forest. The annual radial growth series covers 121 years and the climatic water balance series 140 years. These unique time series enable a quantitative assessment of multidecadal drought and heat impacts on growth and mortality of forest trees on a regional spatial scale. Data compiled here suggest that the mortality of desiccated trees in the Black Forest during the last 68 years is driven by the climatic water balance. Decreasing climatic water balance coincided with an increase in tree mortality and growth decline. Consecutive hot and dry summers enhance mortality and growth decline as a consequence of drought legacies lasting several years. The sensitivity of tree growth and mortality to changes in the climatic water balance increases with the decreasing trend of the climatic water balance. The findings identify the climatic water balance as the main driver of mortality and growth variation during the 68-year observation period on a landscape-scale including a variety of different sites. They suggest that bark beetle population dynamics modify mortality rates. They as well provide evidence that the mortality during the last 140 years never was as high as in the most recent years.

Impact of Abiotic Factors on Population Dynamics of Leaf Miner, Aproaerema modicella D. and Its Natural Enemies in Groundnut

Groundnut leaf miner (Aproaerema modicella. D.) is an important leaf feeding insect in groundnut that significantly reduces the pod yield up to 50 per cent. The growth and development of this insect pest is closely associated with the abiotic weather parameters prevailing in a particular location. Due to paucity of information available on the population dynamics of groundnut leaf miner with abiotic weather factors, a study was undertaken in Erode district of Tamil Nadu during Summer, 2023. Groundnut leaf miner damages were recorded through the fixed plots survey and the adult moth activities were monitored through pheromone traps at weekly intervals. From this study it was found that, the leaf miner incidences were observed from 30 days after sowing. The highest mean leaf miner mean damage (17.84%), pheromone adult catches (58.38 nos./5 traps), coccinellid beetle population (4.70 nos./10 plants) and spider population (5.17 nos./10 plants) were observed during 9th SMW. Whereas, the rove beetle population was maximum (4.62 nos./10 plants) during 10th SMW. The correlation study revealed that the maximum temperature had positive correlation and rainfall had negative correlation with the populations of groundnut leaf miner and its natural enemies. The multiple linear regression analysis indicated that the weather parameters together had 66.00 to 95.00 per cent influence on the groundnut leaf miner and its natural enemy population. The present study clearly indicated that, the population of groundnut leaf miner and its damage levels were closely related to the abiotic weather parameters prevailed in the study area during entire crop duration. Better understanding of the weather factors resulted in better leaf miner management and more net profit for the groundnut growers.

Factors associated with bark beetle infestations of Colorado Plateau ponderosa pine using repeatedly-measured field plots

Decades of research have brought increasing focus to the biotic and abiotic factors associated with bark beetle infestation of North American conifers. Information is lacking, however, regarding beetle-caused mortality for ponderosa pine of the Colorado Plateau. From 1995 to 2019, we installed and periodically remeasured permanent plots in this forest type with a goal of identifying factors related to infestation probability including tree and stand characters, and abiotic factors such as temperature and precipitation. Forty-eight sites were distributed throughout the Colorado Plateau, each with two transects of 10 contiguous ∼ 0.04 ha circular plots. Stand and tree conditions were measured or interpolated for each year from plot establishment in 1995 until the final measurements in 2019. Temperature, precipitation, and other abiotic conditions were estimated from Daymet interpolations. We used a generalized linear mixed model to identify significant explanatory variables resulting in the best accuracy of predicting stem-level bark beetle-caused pine mortality. Tree and stand conditions were found related to the probability of infestation. Pines >15.2 cm dbh were more likely to become infested compared to pines below that threshold; no relationship was found above that breakpoint. Similarly, stems 80–180 years old had elevated probability of infestation compared to stems < 80 years; stems > 180 years were intermediate. Pines with poor crown vigor (low crown volume, suppressed or intermediate canopy position) were more likely to become infested compared to pines with good crown vigor (high crown volume, dominant or open grown canopy position). Pine basal area (BA), a surrogate for intra-species competition, was positively related to probability of infestation. Pine BA infested the previous year, a surrogate for beetle population size, was also positively related to probability of infestation. Several drought- and precipitation-related variables resulted in similar model accuracy. Best model fit among these, by a slight margin, was contemporaneous climate water deficit (CWD), a measure of plant water stress, summed from April-August. Increasing CWD was associated with increased probability of infestation. Finally, counts of days above 16 °C the previous year were negatively related to infestation probability. That is, relatively warm weather during the previous year was associated with reduced beetle success, possibly because it can result in fractional beetle life cycles that disrupt synchronized attacks on new hosts or leave overwintering brood in less cold hardy life stages.

Population demographic history and evolutionary rescue: Influence of a bottleneck event.

Rapid environmental change presents a significant challenge to the persistence of natural populations. Rapid adaptation that increases population growth, enabling populations that declined following severe environmental change to grow and avoid extinction, is called evolutionary rescue. Numerous studies have shown that evolutionary rescue can indeed prevent extinction. Here, we extend those results by considering the demographic history of populations. To evaluate how demographic history influences evolutionary rescue, we created 80 populations of red flour beetle, Tribolium castaneum, with three classes of demographic history: diverse populations that did not experience a bottleneck, and populations that experienced either an intermediate or a strong bottleneck. We subjected these populations to a new and challenging environment for six discrete generations and tracked extinction and population size. Populations that did not experience a bottleneck in their demographic history avoided extinction entirely, while more than 20% of populations that experienced an intermediate or strong bottleneck went extinct. Similarly, among the extant populations at the end of the experiment, adaptation increased the growth rate in the novel environment the most for populations that had not experienced a bottleneck in their history. Taken together, these results highlight the importance of considering the demographic history of populations to make useful and effective conservation decisions and management strategies for populations experiencing environmental change that pushes them toward extinction.

Patterns in the Distribution and Abundance of the Post-Outbreak Population of the Coconut Leaf Beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) in Albay, Philippines

Field monitoring of the coconut leaf beetle (CLB) population in old stands (more than 7 years old) and young stands of coconut (3-5 years old) was conducted in Albay Philippines where an outbreak of the pest occurred in 2006. The study was conducted to characterize the changes in the population of the CLB over time and space and to relate these changes to the infestation pattern, age of palms, development and reproduction of the pest, growth, and development of the coconut leaf. The spatial distribution of the CLB population as well as the infested palms were aggregated throughout the monitoring period based on the Index of dispersion and Lloyd’s mean crowding. Development time and reproduction of CLB is inferred to be synchronous with the emergence of each leaflet in the spear of coconut which has an average of 23 days before another leaflet emerges. This complemented the biology studies where CLB was able to complete from egg to adult in 34.33±2.59 and 32.00±0.93 days in females for both laboratory and greenhouse studies. The infestation of CLB was shown not to spread even if there was an increase in the population.

Organic Management Approaches of Stem Borer in Rice Ecosystem of Assam

Stem borer is the only insect pest which attacks the rice plant starting from tillering upto maturity stage and is of great challenge to manage due to its cryptic behavior and nocturnal habit. The experiment was laid out in the experimental field of AAU-Assam Rice Research Institute, Assam Agricultural University, Titabar both in kharif and rabi season during 2019-2022 taking three popular rice varieties of Assam, Ranjit, Ranjit Sub-1 and Gitesh. Seeds were treated with a solution of Pseudomonas florescense (10 g/liter of water /kg of seed for 12 hrs in organic and with Chlorantraniliprole 18.5 SC @ 30 g/a.i in chemical treatment and without treating the seeds in farmers’ practice plot and sown both in kharif season and rabi season. The foliar application of Beauveria bassiana (5gm/l/ha), Pseudomonas florescense (20g/l/ha) and neem product (5g/liter/ha) in organic plot and insecticide application with Chlorantraniliprole 18.5 SC @ 30 g/a.i. in the chemical plot was done at 45 days after transplanting (DAT) without application of any biopesticide or insecticide in farmers’ practice plot. The dead heart incidence drastically reduced both in chemical (6.19%) and organic treatment (7.23%) without significant difference at 65 DAT in Ranjit. The benefit cost ratio was 2.32 and 2.06 in chemical and organic approach respectively, but it was 1.78 in farmers’ practice. The use of B. bassiana, P. florescense and neem products were found to be safer to the predators as the spider and coccinellid beetle population in organic treatment (10.59 and 9.49 number/hill) was at par with farmers’ practice (12.83 and 11.67 number/hill), respectively.

Seasonal incidence of major insect pests of bottle gourd (Lagenaria siceraria) in South-western Haryana

Bottle gourd is an important vegetable crop that fetches recurrent income from farmers. The present investigation was carried out during the kharif season of 2019 to study the incidence of prevailing four insect pests of bottle gourd in relation to weather. The seasonal incidence of major insect pests such as Aulacophora foveicollis Lucas, Bactrocera cucurbitae Coquillett, Aphis gossypii Glover and Bemicia tabaci Gennadius was studied. The fruit infestation by Bactrocera cucurbitae was initiated in the 34th SMW, and the maximum infestation was noticed in the 36th SMW. The fruit fly infestation was significant and positively correlated with evening relative humidity and rainfall. Aulacophora foveicollis incidence in bottle gourd was maximum in the 38th SMW. The beetle population was significantly and negatively correlated with minimum temperature and evening relative humidity. The maximum infestation of aphids and whitefly was noticed in the later stage of the crop during the 39th SMW, and the aphid population was significantly correlated with minimum temperature, evening relative humidity and rainfall, whereas the whitefly population was correlated significantly with evening relative humidity and rainfall.

Mixed sex pheromone lures for combined captures of Agriotes and Limonius pest click beetles in North America

AbstractSex pheromone lures are effective tools for monitoring and potentially controlling populations of pest click beetles (Coleoptera: Elateridae). To date, these lures are genus‐specific (e.g., Limonius spp.) or species‐specific (e.g., Agriotes lineatus Linnaeus). However, if sympatric heterogeners were not to be repelled by each other's pheromones, trap lures effective for multiple elaterid genera could be developed, improving cost efficiency in elaterid pest management programs. In both western and eastern North America, several species of Agriotes spp. and Limonius spp. co‐occur and inflict similar crop damage. We investigated whether the sex pheromones of these species can be combined in a mixed lure without reducing its attractiveness to all target species. In western Canada, we show that the pheromones of A. lineatus (geranyl butanoate &amp; geranyl octanoate) and Limonius spp. [(E)‐4‐ethyloct‐4‐enoic acid (limoniic acid)] can be combined without significantly reducing captures of male A. lineatus, L. canus (LeConte), L. californicus (Mannerheim) and L. infuscatus (Motschulsky) relative to traps baited with species‐specific lures for A. lineatus and Limonius spp.. Similarly, the pheromone of A. obscurus (Linnaeus) (geranyl hexanoate &amp; geranyl octanoate) and limoniic acid can be combined without significantly reducing trap captures of male L. canus, L. infuscatus and L. californicus but reduced A. obscurus captures relative to traps baited only with the A. obscurus pheromone. In eastern Canada, combining pheromones for Agriotes mancus (Say) (geranyl butanoate &amp; geranyl hexanoate) and limoniic acid reduced captures of A. mancus but not A. pubescens (Melsheimer) and A. sputator (Linnaeus). These data imply that pheromones of select elaterid heterogeners can be combined in a ‘catch‐more’ pheromone lure to effectively monitor for, or possibly control, multiple elaterid pests, but that such mixed lures should be evaluated for each species combination.

Drought occurrence and forest management: Interrelated drivers of sanitary logging in central México temperate forests

Drought exacerbates forest pest outbreaks, causing widespread tree mortality. In México, to control bark beetle outbreaks, mandatory sanitary logging is carried out by the landowners who can use or sell the resulting wood. We analyzed the temporal trend of reported bark beetle outbreaks and their relationship to drought conditions; and assessed the intensity of the sanitary logging in relation to land tenure type and the pre-existing Forest Management Program (FMP) as a proxy to determine whether sanitary logging is being used only for its primary purpose: bark beetle population control. We used official records of bark beetle outbreaks (n = 11,151) on four major conifer species (Abies religiosa, Pinus hartwegii, P. pseudostrobus, and P. oocarpa) that triggered sanitary logging authorizations (n = 1,968) between 2009 and 2021 in two highly affected states: Michoacán and Estado de México. Results showed that reported bark beetle outbreaks increased from an average of 38 in 2009 to 1,051 in 2021, and were associated with droughts that occurred up to two years earlier. More severe droughts were recorded in Estado de México, but more sanitary logging authorizations were issued in Michoacán (829 and 1,139, respectively). In Michoacán, the area logged was smaller, but the sanitary logging was more intensive (2,623 ha, x̅ 139 m3/ha of wood extracted) compared to Estado de México (9,227 ha, x̅ 38 m3/ha of wood extracted). These sanitary logging interventions occurred equally on communal and private lands, but from 58% (Michoacán) to 69% (Estado de México) occurred on properties without a pre-existing FMP. While the results suggest that in some areas, particularly in Michoacán, sanitary logging may serve as a legal pass to harvest timber, further research is needed on ecological and social issues, such as: forest characteristics that may influence beetle reproduction and dispersal, local pest management practices, forest governance and conflicts, and the effectiveness of technical assistance and monitoring to control outbreaks, among others.

Genomic virulence features of Beauveria bassiana as a biocontrol agent for the mountain pine beetle population

BackgroundThe mountain pine beetle, Dendroctonus ponderosae, is an irruptive bark beetle that causes extensive mortality to many pine species within the forests of western North America. Driven by climate change and wildfire suppression, a recent mountain pine beetle (MPB) outbreak has spread across more than 18 million hectares, including areas to the east of the Rocky Mountains that comprise populations and species of pines not previously affected. Despite its impacts, there are few tactics available to control MPB populations. Beauveria bassiana is an entomopathogenic fungus used as a biological agent in agriculture and forestry and has potential as a management tactic for the mountain pine beetle population. This work investigates the phenotypic and genomic variation between B. bassiana strains to identify optimal strains against a specific insect.ResultsUsing comparative genome and transcriptome analyses of eight B. bassiana isolates, we have identified the genetic basis of virulence, which includes oosporein production. Genes unique to the more virulent strains included functions in biosynthesis of mycotoxins, membrane transporters, and transcription factors. Significant differential expression of genes related to virulence, transmembrane transport, and stress response was identified between the different strains, as well as up to nine-fold upregulation of genes involved in the biosynthesis of oosporein. Differential correlation analysis revealed transcription factors that may be involved in regulating oosporein production.ConclusionThis study provides a foundation for the selection and/or engineering of the most effective strain of B. bassiana for the biological control of mountain pine beetle and other insect pests populations.