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1.
Molecules ; 27(13)2022 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-35807397

RESUMO

Volatile cues can play a significant role in the location and discrimination of food resources by insects. Dung beetles have been reported to discriminate among dung types produced by different species, thereby exhibiting behavioral preferences. However, the role of volatile organic compounds (VOCs) in dung localization and preference remains largely unexplored in dung beetles. Here we performed several studies: firstly, cage olfactometer bioassays were performed to evaluate the behavioral responses of Bubas bison (Coleoptera: Scarabaeidae) to VOCs emanating from fresh horse, sheep, and cattle dung; secondly, concurrent volatilome analysis was performed to characterize volatilomes of these dung types. Bubas bison adults exhibited greater attraction to horse dung and less attraction to cattle dung, and they preferred dung from horses fed a pasture-based diet over dung from those fed lucerne hay. Volatilomes of the corresponding dung samples from each livestock species contained a diverse group of alkanes, alkenes, alkynes, alcohols, aldehydes, ketones, esters, phenols, and sulfurous compounds, but the composition and abundance of annotated VOCs varied with dung type and livestock diet. The volatilome of horse dung was the most chemically diverse. Results from a third study evaluating electroantennogram response and supplementary olfactometry provided strong evidence that indole, butyric acid, butanone, p-cresol, skatole, and phenol, as well as toluene, are involved in the attraction of B. bison to dung, with a mixture of these components significantly more attractive than individual constituents.


Assuntos
Bison , Besouros , Compostos Orgânicos Voláteis , Animais , Bovinos , Besouros/fisiologia , Fezes , Cavalos , Gado , Ovinos
2.
Biol Lett ; 18(7): 20220109, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35857889

RESUMO

Temperature profoundly impacts insect development, but plasticity of reproductive behaviours may mediate the impacts of temperature change on earlier life stages. Few studies have examined the potential for adult behavioural plasticity to buffer offspring from the warmer, more variable temperatures associated with climate change. We used a field manipulation to examine whether the dung beetle Phanaeus vindex alters breeding behaviours in response to temperature changes and whether behavioural shifts protect offspring from temperature changes. Dung beetles lay eggs inside brood balls made of dung that are buried underground. Brood ball depth impacts the temperatures offspring experience with consequences for development. We placed adult females in either control or greenhouse treatments that simultaneously increased temperature mean and variance. We found that females in greenhouse treatments produced more brood balls that were smaller and buried deeper than controls, suggesting brood ball number or burial depth may come at a cost to brood ball size, which can impact offspring nutrition. Despite being buried deeper, brood balls from the greenhouse treatment experienced warmer mean temperatures but similar amplitudes of temperature fluctuation relative to controls. Our findings suggest adult behaviours may partially buffer developing offspring from temperature changes.


Assuntos
Besouros , Animais , Besouros/fisiologia , Fezes , Feminino , Temperatura
3.
J Insect Sci ; 22(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35763317

RESUMO

Understanding insect movement and distribution is critical for developing an effective insect pest management protocol. Movement and distribution of adult Cryptolestes ferrugineus (Stephens) in response to nominal temperature differences of 5, 10, 15, and 20°C in 1- and 2-m horizontal columns filled with 12.5% moisture content wheat were studied in 24, 48, and 72 h of movement times. In the wheat columns without temperature differences, adults had a diffusion distribution pattern caused by their random movement. Adults showed bias movement to the warmer grain in wheat columns with temperature differences and preferred the warmer grain regardless of the magnitude of temperature differences in less than 24 h. Their distribution did not have significant differences among different movement times in 1- or 2-m columns. About 40% of adults moved to the warmer wheat located at 0.4 to 0.5 m in the 1 m column but did not move to the warmer wheat located at 0.9 to 1 m in the 2-m column. Therefore, length of grain column influenced detection of warmer grain by insects. Adults under different temperatures had a similar response as that under linear temperature gradients.


Assuntos
Besouros , Animais , Besouros/fisiologia , Grão Comestível , Insetos , Temperatura , Triticum
4.
J Exp Biol ; 225(14)2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35770514

RESUMO

The ladybird beetle (Coccinella septempunctata) is known for swift deployment of its elytra, an action that requires considerable power. However, actuation by thoracic muscles alone may be insufficient to deploy elytra at high speed because the maximum mechanical power that elytral muscles can produce is only 70% of that required for initiation of deployment. Nevertheless, the elytra open rapidly, within 3 ms in the initial phase, at a maximum angular velocity of 66.49±21.29 rad s-1, rivaling the strike velocity of ant lion (Myrmeleon crudelis) mandibles (65±21 rad s-1). Here, we hypothesize that elytra coupling may function as an energy storage mechanism that facilitates rapid opening by releasing elastic strain energy upon deployment. To test this hypothesis and better understand the biomechanics of elytra deployment, we combined micro-computed tomography and scanning electron microscopy to examine the microstructure of the coupling of paired elytra. We found that two rows of setae on the internal edges of the elytra coupling structure undergo elastic deformation when the elytra are locked together. Kinematics observations and mathematical modeling suggest that the elastic potential energy stored in the compressed setae generates 40% of the power required for deployment of elytra. Our findings broaden insights into how ladybirds actuate elytra opening by a strategy of using both muscles and elastic microstructures, and demonstrate a distributed pattern of actuation that adapts to geometrical constraints in elytra locking.


Assuntos
Besouros , Animais , Fenômenos Biomecânicos/fisiologia , Aves , Besouros/fisiologia , Microscopia Eletrônica de Varredura , Sensilas , Microtomografia por Raio-X
5.
Braz J Biol ; 84: e260092, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35674602

RESUMO

Ground beetles (Carabid beetles) may be found in virtually all of the world's habitats. They are one of the three most diverse families of extant beetles, with 34,275 species documented, and they serve as vital ecological markers in all environments. Edaphic living beetles catch and eat a wide variety of arthropods that live in the soil. In the case of weeds, most of the ground beetles eat their seeds and help regulate their populations. The findings of a field study in agrocenoses in South-East Kazakhstan from 2019 to 2020 are presented in this article. Twenty-seven ground beetle species from 9 genera were discovered as a consequence of the study. 670 soil traps yielded a total of 1012 beetles. Polytopic mesophilic beetles provide the foundation of the agrocenoses fauna. Hygrophils, mesophiles, and eurybionts are among the beetles found in irrigated areas, as are mixed and herbivorous species. The Carabidae family of beetles is the most numerous in fields and steppe settings. As a result, mixed-diet beetles can be found depending on the habitat and air temperature. The species of beetles in all fields in the investigation area are in accordance with the insects' complex. During the growth season, the diet of beetles shifts: predatory beetles take precedence initially, followed by mixed-diet beetles.


Assuntos
Besouros , Animais , Besouros/fisiologia , Produtos Agrícolas , Cazaquistão , Comportamento Predatório/fisiologia , Solo
6.
Plant Sci ; 321: 111319, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35696919

RESUMO

Climate change is expected to intensify bark beetle population outbreaks in forests globally, affecting biodiversity and trajectories of change. Aspects of individual tree resistance remain poorly quantified, particularly with regard to the role of phenolic compounds, hindering robust predictions of forest response to future conditions. In 2003, we conducted a mechanical wounding experiment in a Norway spruce forest that coincided with an outbreak of the bark beetle, Ips typographus. We collected phloem samples from 97 trees and monitored tree survival for 5 months. Using high-performance liquid chromatography, we quantified induced changes in the concentrations of phenolics. Classification and regression tools were used to evaluate relationships between phenolic production and bark beetle resistance, in the context of other survival factors. The proximity of beetle source populations was a principal determinant of survival. Proxy measures of tree vigor, such as crown defoliation, mediated tree resistance. Controlling for these factors, synthesis of catechin was found to exponentially increase tree survival probability. However, even resistant trees were susceptible in late season due to high insect population growth. Our results show that incorporating trait-mediated effects improves predictions of survival. Using an integrated analytical approach, we demonstrate that phenolics play a direct role in tree defense to herbivory.


Assuntos
Besouros , Picea , Animais , Besouros/fisiologia , Herbivoria , Fenóis , Floema
7.
J Insect Sci ; 22(3)2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35560005

RESUMO

Monochamus alternatus, the dominant vector of Bursaphelenchus xylophilus (Aphelenchida: Aphelenchoididae), has caused immense damage to forest resources. In China, this vector was native to the southern regions but has spread northward recently. To adapt to more challenging environments in the northern winter, M. alternatus has evolved an intricate strategy for overwintering, which remains largely unknown. Herein, we compared the transcriptome data of the overwintering and non-overwintering larvae of M. alternatus larvae to investigate the molecular mechanisms in overwintering. A total of 53.10 GB clean bases and 28, 245 unigenes were obtained by RNA-seq. Analysis of 2597 upregulated and 2429 downregulated unigenes, as well as the enrichment of DEGs showed that many genes and pathways were jointly involved in the overwintering period. Besides, the accuracy of the RNA-seq data was tested by using qPCR experiment involving 13 selected genes. The results revealed that the overwintering process relied largely on the energy allocation trade-off. Specifically, overwintering M. alternatus inhibited energy-intensive activities, such as growth and molting, detoxification, and trehalose transport, and the reserved energy was skewed towards the synthesis of antifreeze compounds and immune response to cope with the deleterious effects of winter.


Assuntos
Besouros , Animais , China , Besouros/fisiologia , Perfilação da Expressão Gênica , Larva/genética , Transcriptoma
8.
Sci Total Environ ; 838(Pt 1): 155906, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-35580677

RESUMO

Forest disturbances modify microhabitats along the different vertical strata, triggering structural and functional changes in forest-dwelling beetle communities. However, the effects of multiple environmental factors can be complex to detect in ecosystems that offer a broad variety of microhabitats for a great variety of beetle species. This is the case in Patagonian temperate forests, where the use of remote sensing provides an opportunity to evaluate the sensitivity of beetle species to environmental changes. Here, we identified the environmental drivers of forest-dwelling beetle communities in the ground and canopy of 34 north Patagonian-forest landscapes. We analyzed the associations of the taxonomic and functional diversity of five trophic guilds with 30 remote-sensing variables of landscape structure, composition, and disturbances; vegetation and soil properties; and climate and physical variables. Hierarchical clustering analysis was used to identify trophic guilds responding similarly to predictors. Segmented regression analysis was used to evaluate functional redundancy from taxonomic-functional richness relationships. A total of 583 species (23,848 individuals) of beetles were recorded for both strata. The effects of environmental variables were heterogeneous across strata and guilds. Canopy beetles were especially sensitive to early successional conditions, and canopy attributes, but also benefited from the canopy openness. Forest specialists of the ground and canopy responded differently to environmental variables. Ground-dwelling beetles were mostly affected by fires, human modifications, edge closeness, high temperatures, and soil properties, responding weakly to canopy properties. Functional redundancy varied weakly along environmental gradients, being more likely in local communities of ground-dwelling beetles mostly composed of species with overlapping functional roles. Contrasting environmental responses between ground and canopy beetles, as well as among beetles of different trophic guilds, should arise from microhabitats that vary across strata and interact differently with response traits.


Assuntos
Besouros , Animais , Biodiversidade , Besouros/fisiologia , Ecossistema , Florestas , Solo
9.
J Evol Biol ; 35(6): 855-867, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35506566

RESUMO

Whole-organism performance, including locomotor activity, is an important fitness trait in many animals. Locomotor activity is often classified into sprint speed and locomotor endurance and differences in sprint speed and locomotor endurance affect on other traits such as life-history traits. Previous studies found that locomotor endurance, sprint speed and brain dopamine (DA) levels are correlated with artificial selection for death feigning (an anti-predator behaviour that we refer to as 'death-feigning syndrome') in some insect species. Thus, if the syndrome has a genetic basis, death feigning, sprint speed and brain DA levels may be affected by artificial selection for locomotor endurance. We artificially selected for locomotor endurance over 10 generations in the red flour beetle Tribolium castaneum, and established higher (H) and lower activity (L) strains, then compared their death-feigning behaviour, sprint speed and brain DA levels. H-strain beetles exhibited significantly shorter duration of death-feigning, and significantly higher sprint speeds, suggesting variation in death-feigning syndrome. Surprisingly, although brain DA expression affects various animal behaviours, we found no significant differences in the brain DA expressions of H- and L-strain beetles. Thus, our results imply genetic correlations between locomotor endurance, sprint speed and death feigning, but not with brain DA expression, suggesting that differences in the biogenic amine results of our and previous studies may reflect differences in behavioural expression mechanisms.


Assuntos
Besouros , Tribolium , Animais , Besouros/fisiologia , Resposta de Imobilidade Tônica/fisiologia , Locomoção , Tribolium/genética
10.
Pest Manag Sci ; 78(8): 3697-3703, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35620873

RESUMO

BACKGROUND: Stegobium paniceum (Coleoptera, Anobiidae) is an important pest of stored products causing severe damage to dried Chinese medicinal plant materials (CMPMs). Plant volatiles play an important role in host-searching of insects. The olfactory responses of S. paniceum to the most abundant volatile components of some drugstore attractant CMPMs such as Panax notoginseng, Angelica sinensis, Gastrodia elata and Peucedanum praeruptorum, namely falcarinol, 3-n-butylphthalide, p-cresol and ß-pinene, respectively, were studied by electroantennography (EAG) and behavioural bioassays in six- and four-arm olfactometers. RESULTS: EAG recordings showed that male and female antennae are able to perceive the test compounds in a wide range of concentrations and in a dose-dependent manner. Moreover, for each dose of different compounds tested, no significant differences were found between the mean male and female EAG responses. In six-arm olfactometer bioassays, S. paniceum exhibited positive responses to falcarinol, 3-n-butylphthalide, p-cresol and ß-pinene at doses of 1, 10, 100, 500 and 1000 µg. The most attractive dose was 500 µg for falcarinol, 100 µg for 3-n-butylphthalide, 500 µg for p-cresol and 1000 µg for ß-pinene. Olfactory preferences of S. paniceum, based on comparison of these four compounds at their optimally attractive concentrations in a four-arm olfactometer, were 3-n-butylphthalide > p-cresol > falcarinol > ß-pinene. CONCLUSION: The results indicated that the four volatiles of CMPMs are perceived by the peripheral olfactory system of S. paniceum adults and are able to individually elicit a positive chemotaxis in S. paniceum adults confirming the role of chemical cues in host-plant detection and selection of this pest. Further field studies are needed to evaluate the potential of the attractive compounds identified in this study, particularly 3-n-butylphthalide, to be applied as a novel monitoring and control tool against this storage-beetle pest. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Besouros , Plantas Medicinais , Compostos Orgânicos Voláteis , Animais , China , Besouros/fisiologia , Feminino , Masculino , Controle de Pragas/métodos , Olfato , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/farmacologia
11.
Sci Rep ; 12(1): 8691, 2022 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-35610305

RESUMO

Many dung beetle species show male horn polyphenism, the ability of males to develop into distinct phenotypes without intermediate forms as a response to the larval growth environment. While males with long (majors) and rudimentary (minor) horn have been widely reported in literature, little is known about the existence of individuals with intermediate horn length. Here we investigate the occurrence of intermediates in natural populations of three dung beetle species (Onthophagus furcatus, Copris lunaris and C. hispanus). We analysed the body size-horn length relationship using linear, exponential, and sigmoidal models with different error structures. We inferred the number of individuals in the minor, intermediate, and major groups by combining changepoint analysis and simulation from fitted allometric models. The sigmoidal equation was a better descriptor of the body size-horn length relationship than linear or exponential equations in all the three studied species. Our results indicated that the number of intermediates equals or exceeds the number of minor and major males. This work provides evidence that, at least in the studied species, males with intermediate horn length exist in natural populations. For similar cases we therefore suggest that continuous phenotypic modulation rather than discrete polyphenism can explain variation in male horn allometry.


Assuntos
Besouros , Animais , Tamanho Corporal , Besouros/fisiologia , Larva , Masculino , Fenótipo
12.
Pest Manag Sci ; 78(8): 3305-3313, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35485855

RESUMO

BACKGROUND: Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is an important natural enemy of aphids. Plant species and plant health conditions can affect the behavior of H. axyridis. To determine plant effects on this lady beetle, we examined beetle responses to four cover crops: coriander (Coriadrum sativum L., Apiales: Apiaceae), marigold (Tagetes erecta L., Asterales: Asteraceae), sweet alyssum (Lobularia maritima L., Brassicales: Brassicaceae), and alfalfa (Medicago sativa L., Fabales: Fabaceae). Our goal was to better understand this predator's ovipositional behavior in response to different plants and its olfactory response to the aphid-induced volatiles from these plants. RESULTS: We found that this lady beetle did not have any significant oviposition preference among the four plant species, but H. axyridis preferred to lay eggs on the lower surface of leaves, regardless of the plant species. H. axyridis females had a significant preference for aphid-infested marigolds, but were not attracted by any of the other three cover plants or marigolds without aphid damage. Compared to the uninfested marigold plants, the emission of 12 compounds significantly increased on the aphid-infested marigolds, and two of them were attractive to H. axyridis under suitable concentrations. CONCLUSION: H. axyridis did not show any significant oviposition preference among the four cover crops. Aphid-infested marigolds can attract H. axyridis. Indole and terpinen-4-ol mediated lady beetle attraction. These synomones have potential for manipulating populations of H. axyridis as a component of conservation biological control. © 2022 Society of Chemical Industry.


Assuntos
Afídeos , Besouros , Animais , Afídeos/fisiologia , Besouros/fisiologia , Produtos Agrícolas , Feminino , Humanos , Oviposição , Feromônios/farmacologia , Comportamento Predatório , Olfato
13.
J Econ Entomol ; 115(3): 748-756, 2022 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-35417020

RESUMO

Flea beetles (Coleoptera: Chrysomelidae) of the genus Phyllotreta are major pests of cole crops, canola, and related crops in the mustard family (Brassicaceae). Adults may damage seedlings or larger crop plants, impairing crop growth, rendering crops unmarketable, or killing seedlings outright. The two major North American crucifer pest species, Phyllotreta striolata (F.) and Phyllotreta cruciferae (Goeze), have male-produced pheromones attractive to both female and male adults. We tested the racemic synthetic pheromones, himachaladiene and hydroxyhimachalanone, as well as the host-plant-produced allyl isothiocyanate, alone and in combination, with experimental trapping in Maryland, Virginia, and North Dakota, using clear and yellow sticky traps and the ground-based 'rocket' trap (modified from boll weevil trap). Phyllotreta striolata was consistently attracted to the hydroxyketone, and captures were often enhanced by allyl isothiocyanate (AITC), but its response to pheromones, AITC, and trap color were variable from state to state. Phyllotreta cruciferae was strongly attracted to AITC, but its response to pheromone components varied by state, and this species was found rarely at the Maryland site. Phyllotreta bipustulata (F.) was attracted to the diene component, a new finding for this species. Several other genera of flea beetles were captured, some showing response to the semiochemicals and/or color. Results will be helpful in monitoring and possibly population suppression; however, further research is necessary to develop more efficient syntheses, optimal lure loadings, combinations, and controlled release methods.


Assuntos
Brassica napus , Besouros , Sifonápteros , Animais , Besouros/fisiologia , Feminino , Masculino , Feromônios/farmacologia , Plantas
14.
Pest Manag Sci ; 78(6): 2477-2491, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35315203

RESUMO

BACKGROUND: Natural enemy pest control is becoming more desirable as restrictions increase on pesticide use. Carabid beetles are proven agents of natural-enemy pest control (NPC), controlling pests and weeds in crop areas. Agro-ecological measures can be effective for boosting carabid abundance and associated NPC, but the benefits of specific interventions to production are seldom communicated to farmers. We explore pathways to improved NPC by engaging farmers and increasing knowledge about farm management practices (FMPs) beneficial to carabids using engagement materials. We used a questionnaire to measure awareness, beliefs and attitudes to carabids and analysed these within a framework of the Theory of Planned Behaviour (TPB), relative to a control group. RESULTS: We found awareness of carabid predation to be associated with beliefs of pest and weed control efficacy. Within the framework of TPB, we found that current implementation of FMPs was higher if farmers perceived them to be both important for carabids and easy to implement. This was also true for future intention to implement, yet the perceived importance was influenced by engagement materials. Field margins/buffer strips and beetle banks (16% and 13% of responses) were the most favoured by farmers as interventions for carabids. CONCLUSION: The TPB is a valuable tool with which to examine internal elements of farmer behaviour. In this study self-selected participants were influenced by online engagement in a single intervention, proving this approach has the potential to change behaviour. Our results are evidence for the effectiveness of raising awareness of NPC to change attitudes and increase uptake of sustainable practices.


Assuntos
Besouros , Praguicidas , Agricultura/métodos , Animais , Besouros/fisiologia , Fazendeiros , Humanos , Intenção , Controle de Pragas , Inquéritos e Questionários
15.
Oecologia ; 199(3): 527-535, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35298703

RESUMO

Natural variation in light has historically correlated with seasonality, providing an honest cue to organisms with seasonal life history cycles. However, with the onset of widespread light at night (LAN), the reliability of light as a cue has decreased in polluted areas, making its timing or intensity potentially clash with temperature trends. These clashing cues may influence biological systems on multiple levels. Yet, a few studies have connected behavioral underpinnings and larger community-level processes, resulting in a knowledge gap bridging individual-, population-, and community-level responses to mismatched cues. We experimentally investigated impacts of cool temperature and LAN on a lady beetle-aphid-fava system to test how light and temperature influenced aphid population growth and their underlying behavioral drivers. We used Coccinella septempunctata and Coleomegilla maculata beetles to understand the interaction of the environment and predation on pea aphid (Acyrthosiphon pisum) population growth. Aphids and their predators reacted differently to variation in light and temperature, influencing the strength of aphid-driven and predator-driven dynamics in the different conditions. We observed evidence of aphid-driven dynamics in the cool, light conditions where aphids excel and exhibited strong anti-predator behavior. In contrast, we found stronger predator-driven dynamics in warm conditions where lady beetle predatory success was higher. Overall, we found that LAN has context-dependent effects on insect communities due to the varied responses each player has to its environment.


Assuntos
Afídeos , Besouros , Animais , Afídeos/fisiologia , Besouros/fisiologia , Ervilhas , Crescimento Demográfico , Comportamento Predatório , Reprodutibilidade dos Testes
16.
PLoS One ; 17(3): e0265222, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35298496

RESUMO

Organisms alter their phenotypes in response to changing environmental conditions. The developmental basis of this phenomenon, phenotypic plasticity, is a topic of broad interest in many fields of biology. While insects provide a suitable model for studying the genetic basis of phenotypic plasticity, the physiological aspects of plasticity are not fully understood. Here, we report the physiological basis of polyphenism, an extreme form of phenotypic plasticity by utilizing a dung beetle species, Onthophagus taurus. We highlighted the metabolome between sexes as well as two distinct male morphs-large and small horns. Unlike results from previous transcriptomic studies, the comparative metabolomic study revealed that differences in metabolite level were more prominent between animals with different body sizes than different sexes. Our results also indicate that specific metabolites and biochemical pathways may be active during horn size determination.


Assuntos
Besouros , Adaptação Fisiológica , Animais , Evolução Biológica , Tamanho Corporal , Besouros/fisiologia , Insetos , Masculino , Fenótipo
17.
PLoS One ; 17(3): e0266076, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35358260

RESUMO

Biodiversity research relies largely on knowledge about species responses to environmental gradients, assessed using some commonly applied sampling method. However, the consistency of detected responses using different sampling methods, and thus the generality of findings, has seldom been assessed in tropical ecosystems. Hence, we studied the response consistency and indicator functioning of beetle assemblages in altitudinal gradients from two mountains in Malaysia, using Malaise, light, and pitfall traps. The data were analyzed using generalized linear mixed-effects models (GLMM), non-metric multidimensional scaling (NMDS), multivariate regression trees (MRT), and indicator species analysis (IndVal). We collected 198 morpho-species of beetles representing 32 families, with a total number of 3,052 individual beetles. The richness measures generally declined with increasing altitude. The mountains differed little in terms of light and Malaise trap data but differed remarkably in pitfall-trap data. Only light traps (but not the other trap types) distinguished high from middle or low altitudes in terms of beetle richness and assemblage composition. The lower altitudes hosted about twice as many indicators as middle or high altitudes, and many species were trap-type specific in our data. These results suggest that the three sampling methods reflected the altitudinal gradient in different ways and the detection of community variation in the environment thus depends on the chosen sampling method. However, also the analytical approach appeared important, further underlining the need to use multiple methods in environmental assessments.


Assuntos
Besouros , Altitude , Animais , Biodiversidade , Besouros/fisiologia , Ecossistema , Humanos , Malásia , Síndrome
18.
Int J Mol Sci ; 23(6)2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35328631

RESUMO

Agasicles hygrophila is a classical biological agent used to control alligator weed (Alternanthera philoxeroides). Previous research has indicated that the heat shock factor (HSF) is involved in regulating the transcriptional expression of Hsp70 in response to heat resistance in A. hygrophila. However, the regulatory mechanism by which AhHsf regulates the expression of AhHsp70 remains largely unknown. Here, we identified and cloned a 944 bp AhHsp70 promoter (AhHsp70p) region from A. hygrophila. Subsequent bioinformatics analysis revealed that the AhHsp70p sequence contains multiple functional elements and has a common TATA box approximately 30 bp upstream of the transcription start site, with transcription commencing at a purine base approximately 137 bp upstream of ATG. Promoter deletion analyses revealed that the sequence from -944 to -744 bp was the core regulatory region. A dual-luciferase reporter assay indicated that overexpressed AhHsf significantly enhanced the activity of AhHsp70p. Furthermore, qPCR showed that AhHsp70 expression increased with time in Spodoptera frugiperda (Sf9) cells, and AhHsf overexpression significantly upregulated AhHsp70 expression in vitro. Characterization of the upstream regulatory mechanisms demonstrated that AhHsf binds to upstream cis-acting elements in the promoter region of AhHsp70 from -944 to -744 bp to activate the AhHSF-AhHSP pathway at the transcriptional level to protect A. hygrophila from high temperature damage. Furthermore, we proposed a molecular model of AhHsf modulation of AhHsp70 transcription following heat shock in A. hygrophila. The findings of this study suggest that enhancing the heat tolerance of A. hygrophila by modulating the upstream pathways of the Hsp family can improve the biocontrol of A. philoxeroides.


Assuntos
Acanthaceae , Amaranthaceae , Besouros , Termotolerância , Animais , Besouros/fisiologia , Termotolerância/genética , Fatores de Transcrição/genética
19.
Phytopathology ; 112(8): 1795-1807, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35166574

RESUMO

Variation in rate of infection and susceptibility of Pinus spp. to the fungus Cronartium harknessii (syn. Endocronartium harknessii), the causative agent of western gall rust, has been well documented. To test the hypothesis that there is a coevolutionary relationship between C. harknessii and its hosts, we examined genetic structure and virulence of C. harknessii associated with lodgepole pine (P. contorta var. latifolia), jack pine (P. banksiana), and their hybrids. A secondary objective was to improve assessment and diagnosis of infection in hosts. Using 18 microsatellites, we assessed genetic structure of C. harknessii from 90 sites within the ranges of lodgepole pine and jack pine. We identified two lineages (East and West, FST = 0.677) associated with host genetic structure (r = 0.81, P = 0.001), with East comprising three sublineages. In parallel, we conducted a factorial experiment in which lodgepole pine, jack pine, and hybrid seedlings were inoculated with spores from the two primary genetic lineages. With this experiment, we refined the phenotypic categories associated with infection and demonstrated that stem width can be used as a quantitative measure of host response to infection. Overall, each host responded differentially to the fungal lineages, with jack pine exhibiting more resiliency to infection than lodgepole pine and hybrids exhibiting intermediate resiliency. Taken together, the shared genetic structure between fungus and host species, and the differential interaction of the fungal species with the hosts, supports a coevolutionary relationship between host and pathogen.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Besouros , Pinus , Animais , Besouros/microbiologia , Besouros/fisiologia , Pinus/microbiologia , Doenças das Plantas/microbiologia , Plântula
20.
Environ Entomol ; 51(2): 340-350, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35178556

RESUMO

Aggressive bark beetles colonize and kill healthy conifers through pheromone-mediated mass aggregation. In several species, the focal point of aggregation moves progressively from mass-attacked 'focus trees' to adjacent, unattacked 'recipient trees', resulting in infestation growth. This process, termed 'switching', is hypothesized to be mediated in whole or in part by antiaggregation pheromones released by beetles as colonization intensifies on a focus tree. We tested this hypothesis with the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), by using a windvane apparatus that maintained an unbaited, black, cylindrical trap (surrogate for a recipient tree) continuously 4 m downwind from an identical trap baited with synthetic aggregation attractant (surrogate for a focus tree). In two of three replicated trials, addition of pheromone components with antiaggregation activity, endo-brevicomin or verbenone, to the upwind trap caused a significant but small (<15%) increase in the proportion of beetles caught in the downwind trap. In one of two trials with endo-brevicomin, this shift was associated with a significant reduction in catches in the downwind trap and an overall reduction in catches of beetles by the trap pair. This suggests that an inhibitor-induced increase in landings on the recipient relative to the focus tree may be countered by the radial effects of the inhibitor, which at sufficiently high release may reduce responses to both the focus and recipient tree. We discuss spatial factors that might govern the role of antiaggregation pheromones in stimulating infestation growth as well as additional factors that likely govern switching behavior.


Assuntos
Besouros , Pinus , Gorgulhos , Animais , Besouros/fisiologia , Feromônios/farmacologia , Árvores , Gorgulhos/fisiologia , Vento
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