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1.
Glob Chang Biol ; 28(15): 4495-4505, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35574993

RESUMO

Chemical communication via infochemicals plays a pivotal role in ecological interactions, allowing organisms to sense their environment, locate predators, food, habitats, or mates. A growing number of studies suggest that climate change-associated stressors can modify these chemically mediated interactions, causing info-disruption that scales up to the ecosystem level. However, our understanding of the underlying mechanisms is scarce. Evidenced by a range of examples, we illustrate in this opinion piece that climate change affects different realms in similar patterns, from molecular to ecosystem-wide levels. We assess the importance of different stressors for terrestrial, freshwater, and marine ecosystems and propose a systematic approach to address highlighted knowledge gaps and cross-disciplinary research avenues.


Assuntos
Mudança Climática , Ecossistema , Água Doce
2.
J Chem Ecol ; 48(11-12): 841-849, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36302913

RESUMO

Silicon (Si) fertilization alleviates biotic stresses in plants. Si enhances plant resistance against phytophagous insects through physical and biochemical mechanisms. In particular, Si modifies jasmonic acid levels and the emissions of herbivore-induced plant volatiles (HIPVs). Here, we investigated whether Si accumulation in the tissues of maize leaves modifies the emissions of constitutive and herbivore-induced plant volatiles, with cascade deterrent effects on oviposition site selection by Spodoptera exigua Hübner (Lepidoptera: Noctuidae). Maize plants were cultivated in a hydroponic system under three Si concentrations, resulting in three groups of plants expressing different Si concentrations in their tissues (0.31 ± 0.04, 4.69 ± 0.49, and 9.56 ± 0.30 g Si. Kg- 1 DW). We collected volatiles from undamaged and caterpillar-infested plants, and found that Si concentration in plant tissues had no significant impact. Jasmonic acid content was high in insect-infested plants, but was similar across all Si treatments. Oviposition site selection bioassays using fertilized S. exigua females showed that Si concentration in plant tissues did not affect the number of eggs laid on Si-treated plants. In conclusion, our study shows that the Si content in maize tissues does not impact the semiochemical interactions with S. exigua.


Assuntos
Silício , Zea mays , Animais , Feminino , Spodoptera , Silício/farmacologia , Oviposição , Herbivoria , Larva
3.
J Chem Ecol ; 46(7): 590-596, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32583093

RESUMO

Female Harmonia axyridis (Coleoptera: Coccinellidae) produce a sex pheromone to attract males. In the present study, we tested two hypotheses: (i) production of sex pheromone in H. axyridis is conditioned by perception of prey in their vicinity, and (ii) virgin females invest in the production of the sex pheromone, while mated females reduce their pheromone emissions. To test the first hypothesis, newly hatched larvae were divided into three groups: those fed with Ephestia kuehniella eggs, those fed with pea aphids, and those exposed to aphid volatile cues but fed with Ephestia eggs. All females produced a pheromone blend of five-components in similar relative proportions, but with contrasting absolute quantities: Females fed with Ephestia eggs produced lower amounts of pheromone (0.5 ± 0.4 ng.female-1), compared to females fed with aphids (44.2 ± 24.4 ng.female-1). The females of the third group produced intermediate concentrations of pheromone (6.0 ± 3.2 ng.female-1). To test the second hypothesis, two groups of lady beetles were made: one group of females was placed in the presence of males, while females of the other group were not. Mated and virgin females produced statistically similar amounts of pheromone (144.1 ± 49.7 ng and 43.7 ± 24.1 ng.female-1, respectively). These results suggest that H. axyridis females initiate pheromone production upon exposure to volatile cues released by their aphids prey. Females continue to release sex pheromone after mating, probably to increase the chance of multiple mating which is known to improve egg fertility.


Assuntos
Afídeos , Besouros/fisiologia , Comportamento Predatório , Atrativos Sexuais/metabolismo , Comportamento Sexual Animal , Animais , Besouros/química
4.
J Insect Sci ; 18(1)2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29301046

RESUMO

In response to a predator attack, many Aphidinae species release an alarm pheromone, which induces dispersal behavior in other individuals within the colony. The major component of this pheromone is the sesquiterpene (E)-ß-farnesene (Eßf), but variations occur between aphid species. In the present work, we collected, identified, and quantified the alarm pheromone of Aphis craccivora Koch (Hemiptera: Aphididae), before quantifying the escape behavior induced in the neighboring individuals. We compared the semiochemistry and associated behavior of alarm signaling with two other aphid species: Myzus persicae (Sulzer) (Hemiptera: Aphididae) and Aphis fabae Scopoli (Hemiptera: Aphididae). Eßf was the only volatile found for each species. M. persicae produces a higher quantity of Eßf (8.39 ± 1.19 ng per individual) than A. craccivora (6.02 ± 0.82 ng per individual) and A. fabae (2.04 ± 0.33 ng per individual). Following exposure to natural doses of synthetic Eßf (50 ng and 500 ng), A. craccivora respond more strongly than the two other Aphidinae species with 78% of the individuals initiated alarm behavior for 500 ng of Eßf.


Assuntos
Afídeos/química , Feromônios/análise , Sesquiterpenos/análise , Comunicação Animal , Animais , Comportamento Animal , Compostos Orgânicos Voláteis/análise
5.
J Chem Ecol ; 43(2): 164-171, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28097605

RESUMO

Insects often rely on olfaction to communicate with conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations might impact pheromonal communication in insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-ß-farnesene (Eßf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid, Acyrthosiphon pisum, under ambient and elevated CO2 concentrations over several generations. We found that an increase in CO2 concentration reduced the production (i.e., individual content) and emission (released under predation events) of Eßf. While no difference in Eßf neuronal perception was observed, we found that an increase in CO2 strongly reduced the escape behavior expressed by an aphid colony following exposure to natural doses of alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases impact chemical communication in the pea aphid, and could potentially have a cascade effect on interactions with higher trophic levels.


Assuntos
Poluentes Atmosféricos/análise , Comunicação Animal , Afídeos/fisiologia , Dióxido de Carbono/análise , Reação de Fuga/efeitos dos fármacos , Feromônios/metabolismo , Sesquiterpenos/metabolismo , Poluentes Atmosféricos/toxicidade , Animais , Dióxido de Carbono/toxicidade , Besouros/fisiologia , Relação Dose-Resposta a Droga , Reação de Fuga/fisiologia , Feromônios/análise , Comportamento Predatório , Sesquiterpenos/análise
6.
J Insect Sci ; 14: 58, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25373205

RESUMO

The foraging behaviour of a parasitoid insect species includes the host's habitat and subsequent location of the host. Habitats substrate, substrate moisture, and light levels can affect the host searching of different species of parasitoids. However, the depth at which parasitoids concentrate their search effort is another important ecological characteristic and plays an important role in locating a host. Here, we investigated the ability of a pupal parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae), to penetrate and kill fly pupae located at different depths of the substrate. Three different types of substrate were tested: loam soil, compost, and vermiculite substrate. In both loam soil and compost, all of the parasitism activity was restricted to pupae placed directly on the surface. Parasitism activity in vermiculite showed that the average number of pupae parasitized decreased with depth of substrate. These results suggest that fly pupae situated deeper in the substrate are less subjected to parasitism by N. vitripennis.


Assuntos
Dípteros/parasitologia , Vespas/fisiologia , Animais , Feminino , Interações Hospedeiro-Parasita , Masculino , Pupa/parasitologia
7.
J Insect Sci ; 142014.
Artigo em Inglês | MEDLINE | ID: mdl-25528746

RESUMO

Jatropha curcas has been introduced into Niger since 2004 by International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). This plant is cultivated for its oil, which can be used as a Biofuel. Through direct and indirect insect collection methods, an inventory of the insect associated with J. curcas has been conducted in Western Niger during two rainy seasons (from June to October) in 2010 and 2011. We have identified insects belonging to the following families: Acrididae (Oedaleus senegalensis Krauss, Oedaleus nigeriensis Uvarov, Heteracris leani Uvarov, Catantops stramineus Walker, Parga cyanoptera Uvarov, and Acanthacris ruficornis citrina Audinet-Serville), Pyrgomorphidae (Poekilocerus bufonius hieroglyphicus Klug), Cetoniidae (Pachnoda interrupta Olivier, Pachnoda marginata aurantia Herbst, Pachnoda sinuata Heinrich and McClain, and Rhabdotis sobrina Gory and Percheron), Meloidae (Decapotoma lunata Pallas), Pentatomidae (Agonoscelis versicoloratus Dallas, Nezara viridula Linn, and Antestia sp. Kirkaldy), Coreidae (Leptoglossus membranaceus Fabricius and Cletus trigonus Thunberg), and Scutelleridae (Calidea panaethiopica Kirkaldy). Origin and potential impact on J. curcas of all these insect species are presented and discussed. The lower insect's diversity indexes are observed in 2010 and 2011 for Niamey, Saga, and Gaya because of semi-arid character of the Sahelian area.


Assuntos
Produtos Agrícolas , Insetos/fisiologia , Jatropha/parasitologia , Animais , Biodiversidade , Biocombustíveis , Níger
8.
J Chem Ecol ; 39(8): 1129-39, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23793896

RESUMO

Root volatile organic compounds (VOCs), their chemistry and ecological functions have garnered less attention than aboveground emitted plant VOCs. We report here on the identification of VOCs emitted by barley roots (Hordeum vulgare L.). Twenty nine VOCs were identified from isolated 21-d-old roots. The detection was dependent on the medium used for root cultivation. We identified 24 VOCs from 7-d-old roots when plants were cultivated on sterile Hoagland gelified medium, 33 when grown on sterile vermiculite, and 34 on non-sterile vermiculite. The major VOCs were fatty acid derived compounds, including hexanal, methyl hexanoate, (E)-hex-2-enal, 2-pentylfuran, pentan-1-ol, (Z)-2-(pentenyl)-furan, (Z)-pent-2-en-1-ol, hexan-1-ol, (Z)-hex-3-en-1-ol, (E)-hex-2-en-1-ol, oct-1-en-3-ol, 2-ethylhexan-1-ol (likely a contaminant), (E)-non-2-enal, octan-1-ol, (2E,6Z)-nona-2,6-dienal, methyl (E)-non-2-enoate, nonan-1-ol, (Z)-non-3-en-1-ol, (E)-non-2-en-1-ol, nona-3,6-dien-1-ol, and nona-2,6-dien-1-ol. In an olfactometer assay, wireworms (larvae of Agriotes sordidus Illiger, Coleoptera: Elateridae) were attracted to cues emanating from barley seedlings. We discuss the role of individual root volatiles or a blend of the root volatiles detected here and their interaction with CO2 for wireworm attraction.


Assuntos
Besouros/fisiologia , Hordeum/química , Compostos Orgânicos Voláteis/química , Animais , Comportamento Animal/efeitos dos fármacos , Dióxido de Carbono/química , Dióxido de Carbono/farmacologia , Besouros/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Hordeum/metabolismo , Larva/efeitos dos fármacos , Larva/fisiologia , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Compostos Orgânicos Voláteis/farmacologia
9.
J Insect Sci ; 13: 32, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23895458

RESUMO

Most reports published in the field of forensic entomology are focused on Diptera and neglect the Hymenoptera community. However, Hymenoptera are part of the entomofaunal colonization of a dead body. The use of Hymenoptera parasitoids in forensic entomology can be relevant to evaluate the time of death. Hymenoptera parasitoids of the larvae and pupae of flies may play an important role in the estimation of the post-mortem period because their time of attack is often restricted to a small, well-defined window of time in the development of the host insect. However, these parasitoids can interfere with the developmental times of colonizing Diptera, and therefore a better understanding of their ecology is needed. The work reported here monitored the presence of adult Hymenoptera parasitoids on decaying pig carcasses in an urban biotope during the summer season (from May to September). Six families and six species of parasitoids were recorded in the field: Aspilota fuscicornis Haliday (Braconidae), Alysia manducator Panzer, Nasonia vitripennis Walker (Pteromalidae), Tachinaephagus zealandicus Ashmead (Encyrtidae), Trichopria sp. (Diapriidae), and Figites sp. (Figitidae). In the laboratory, five species emerged from pupae collected in the field: Trichopria sp., Figites sp., A. manducator, N. vitripennis, and T. zealandicus. These five species colonize a broad spectrum of Diptera hosts, including those species associated with decomposing carcasses, namely those from the families Calliphoridae, Muscidae, Fanniidae, and Sarcophagidae.


Assuntos
Biodiversidade , Dípteros/parasitologia , Interações Hospedeiro-Parasita , Vespas/fisiologia , Animais , Bélgica , Cidades , Masculino , Pupa/parasitologia , Suínos
10.
J Insect Sci ; 13: 158, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24785375

RESUMO

The multicolored Asian ladybeetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was introduced into Western Europe in the late 1990s. Since the late 2000s, this species has been commonly considered one of the most abundant aphid predators in most Western European countries. In spite of the large amount of research on H. axyridis, information concerning its relative abundance in agroecosystems is lacking. This study aims to evaluate the abundance of H. axyridis within the aphidophage community in four crops situated in southern Belgium: wheat, Triticum aestivum L. (Poales: Poaceae), corn, Zea mays, potato, Solanum tuberosum (Solanales: Solanaceae), and broad bean Vicia faba (Fabales: Fabaceae). In order to assess the species diversity, the collected data were analyzed by considering (1) the species richness and (2) the evenness according to the Shannon diversity index. Eleven aphidophages were observed in every inventoried agroecosystem, including five abundant species: three coccinellids, the seven-spotted ladybug, Coccinella septempunctata L. (Coleoptera: Coccinellidae), the 14-spotted Ladybird, Propylea quatuordecimpunctata, and H. axyridis; one hoverfly, the marmalade hoverfly, Episyrphus balteatus De Geer (Diptera: Syrphidae); and one lacewing, the common green lacewing, Chrysoperla carnea Stephens sensu lato (= s.l.) (Neuroptera: Chrysopidae). Harmonia axyridis has been observed to thrive, breed, and reproduce on the four studied crops. Harmonia axyridis is the most abundant predator of aphids in corn followed by C. septempunctata, which is the main aphid predator observed in the three other inventoried crops. In wheat and potato fields, H. axyridis occurs in low numbers compared to other aphidophage. These observations suggest that H. axyridis could be considered an invasive species of agrosystems, and that potato and wheat may intermittently act as refuges for other aphidophages vulnerable to intraguild predation by this invader. Harmonia axyridis is not the most abundant aphid predator in the main Belgian crops.


Assuntos
Afídeos/fisiologia , Besouros/fisiologia , Produtos Agrícolas , Cadeia Alimentar , Espécies Introduzidas , Animais , Bélgica , Produtos Agrícolas/crescimento & desenvolvimento , Dípteros/fisiologia , Insetos/fisiologia , Densidade Demográfica , Estações do Ano
11.
J Forensic Sci ; 68(4): 1190-1197, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37183668

RESUMO

Human remains detection dogs (HRDD) are commonly used by law enforcement agencies to search for cadavers. Biological material is typically used as a training stimulus, also called aids, to train dogs to recognize the smell of cadavers. While HRDD training approaches have received extensive attention, information remains limited on the olfactory cues used to train them. Here, we aimed to decipher the chemical basis of detection dog olfaction. Five specific objectives were explored to precise whether the composition or the concentration of the training aids drives the HRDDs responses. We recorded the behavioral responses of four HRDDs exposed to different cadaveric-like smells. We found that HRDDs recognized a simplified synthetic aid composed of cadaveric compounds. The lowest concentration at which HRDDs continued to perceive the cadaveric smell was determined. HRDDs were not impacted by slight modifications to the chemical composition of a blend of odors that they have been trained with. HRDDs associated sulfur and nitrogen compounds as human cadaver. Our findings highlight a lack of specificity of HRDDs to cadaveric compounds, which could lead to error of detection. Moreover, all dogs did not positively respond to the same blends, despite being trained with the same aids and procedure. However, we confirmed that dogs could be trained with a simplified blend of molecules. The chemical composition of a training aid has, therefore, high consequences on the performance of the trained animal, and this conclusion opens additional questions regarding olfaction-based detection animals.


Assuntos
Odorantes , Olfato , Humanos , Cães , Animais , Olfato/fisiologia , Cães Trabalhadores , Restos Mortais , Cadáver
12.
Ambio ; 51(8): 1764-1771, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35094246

RESUMO

Actions potentially harmful to the environment that are otherwise illegal are sometimes permitted in cases of emergency. How to define an emergency can therefore be both controversial and highly consequential. In this article, we explore one such contemporary controversy: when the use of neonicotinoid pesticides, banned in the EU, can nevertheless be granted an emergency authorization. We analyse several questions, currently before the EU Court of Justice in the ongoing Pesticide Action Network Europe and Others case, that will determine the scope of an "emergency" in the context of derogating from the Pesticide Regulation, and that may impact how "emergencies" are defined in other legal contexts. We argue that the circumstances do not support a legal finding that emergency authorization is justified in this case, and that, in general, "emergencies" must be narrowly defined when justifying measures that involve risks to human health and the environment.


Assuntos
Praguicidas , Abelhas , Europa (Continente) , Humanos , Neonicotinoides , Praguicidas/toxicidade
13.
Front Insect Sci ; 2: 1079756, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-38468800

RESUMO

The Japanese beetle, Popillia japonica, is native to Japan and became established in North America in the early twentieth century. The beetle was detected in Europe, first in Italy in 2014 and then in Switzerland in 2017. Metropolitan France is at the forefront of the Japanese beetle threat, due to its geographical proximity to the European populations established in the Piedmont, Lombardy and Ticino regions. An express pest risk analysis for metropolitan France was therefore conducted. The most likely pathways for entry include (i) natural dispersion, (ii) trades of plant products with adherent soil and (iii) hitchhiking behaviour, leading to a high probability of entry. The spread rate of P. japonica was also evaluated as high, resulting from natural spread as well as human activities. Given the absence of significant limiting factors, the potential impacts of P. japonica in France will likely be as important as in its current geographic distribution. Although several sources of uncertainty were highlighted throughout the evaluation, none of them has significant impact on the conclusions of the present express pest risk analysis. Measures to prevent entry, establishment and spread of P. japonica are recommended and include surveillance with pheromone traps and control via integrated pest management strategies. However, most efforts should be concentrated on eradication measures while P. japonica is still in the early stages of invasion.

14.
J Insect Sci ; 11: 73, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21867439

RESUMO

Carrion beetles are important in terrestrial ecosystems, consuming dead mammals and promoting the recycling of organic matter into ecosystems. Most forensic studies are focused on succession of Diptera while neglecting Coleoptera. So far, little information is available on carrion beetles postmortem colonization and decomposition process in temperate biogeoclimatic countries. These beetles are however part of the entomofaunal colonization of a dead body. Forensic entomologists need databases concerning the distribution, ecology and phenology of necrophagous insects, including silphids. Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate entomofaunal succession. However, few studies have been conducted in Europe on large carcasses. The work reported here monitored the presence of the carrion beetles (Coleoptera: Silphidae) on decaying pig carcasses in three selected biotopes (forest, crop field, urban site) at the beginning of spring. Seven species of Silphidae were recorded: Nicrophorus humator (Gleditsch), Nicrophorus vespillo (L.), Nicrophorus vespilloides (Herbst), Necrodes littoralis L., Oiceoptoma thoracica L., Thanatophilus sinuatus (Fabricius), Thanatophilus rugosus (L.). All of these species were caught in the forest biotope, and all but O. thoracica were caught in the agricultural biotope. No silphids were caught in the urban site.


Assuntos
Besouros/fisiologia , Meio Ambiente , Suínos/parasitologia , Animais , Bélgica , Ciências Forenses
15.
Forensic Sci Int ; 318: 110569, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33248327

RESUMO

Soil thanatochemistry, defined as the study of the chemical changes occurring during the decomposition of buried corpses, is a young and inadequately documented field of research. In this study, we aim to determine the effects of decomposition on soil physico-chemical properties by combining pedological, chemical, and volatile analyses of soils surrounding buried animals. We examined chemical and volatile changes over time occurring throughout the soil column in two common soil-texture types (sandy loam and loam). We buried dead rats and let them decompose for two months. During their excavations, we characterized the physico-chemical conditions of three soil layers above the rats and one layer below, including (1) pH, dry matter, and electrical conductivity, (2) organic carbon and total nitrogen, (3) bioavailable nutrients (K, Na, Mg, Ca, and P), and (4) volatile organic compounds. Multivariate analyses (permMANOVA) revealed that a decaying rat is associated with changes in soil chemical characteristics in both soil types. However, the observed changes were not homogenous throughout the soil columns. Conditions in soil layers nearest the cadavers changed most during decomposition. We generated a predictive model by combining chemical and volatile analyses (10 % error rate), allowing us to identify key gravesoil indicators that could be used to reveal the former existence of a buried corpse in loam and sandy loam (indicators in order of importance): organic carbon, calcium, pH, conductivity, dimethyl-disulfide, and nitrogen.


Assuntos
Sepultamento , Mudanças Depois da Morte , Solo/química , Animais , Condutividade Elétrica , Elementos Químicos , Ciências Forenses , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Modelos Animais , Análise Multivariada , Análise de Componente Principal , Ratos , Compostos Orgânicos Voláteis/análise
16.
PLoS One ; 16(2): e0247657, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33626104

RESUMO

Mass trapping of gravid females represents one promising strategy for the development of sustainable tools against Aedes aegypti. However, this technique requires the development of effective odorant lures that can compete with natural breeding sites. The presence of conspecific larvae has been shown to stimulate oviposition. Hence, we evaluated the role of four major molecules previously identified from Ae. aegypti larvae (isovaleric, myristoleic, myristic [i.e. tetradecanoic], and pentadecanoic acids) on the oviposition of conspecific females, as well as their olfactory perception to evaluate their range of detection. Using flight cage assays, the preference of gravid females to oviposit in water that previously contained larvae (LHW) or containing the four larval compounds was evaluated. Then, compounds and doses inducing the highest stimulation were challenged for their efficacy against LHW. Only isovaleric acid elicited antennal response, suggesting that the other compounds may act as taste cues. Pentadecanoic acid induced significant oviposition stimulation, especially when dosed at 10 ppm. Myristoleic acid and isovaleric acid deterred oviposition at 10 and 100 ppm, while no effect on oviposition was observed with myristic acid irrespectively of the dose tested. When the four compounds were pooled to mimic larvae's chemical signature, they favored oviposition at 1 ppm but negatively affected egg-laying at higher concentrations. When properly dosed, pentadecanoic acid and the blend of compounds may be promising lures for ovitraps as they could compete with LHW. Due to their low volatility, their effect should be further evaluated under field conditions, in addition with long-range attractants for developing effective tools against gravid females.


Assuntos
Aedes/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Ácidos Graxos Monoinsaturados/farmacologia , Ácidos Graxos/farmacologia , Hemiterpenos/farmacologia , Ácido Mirístico/farmacologia , Oviposição/efeitos dos fármacos , Ácidos Pentanoicos/farmacologia , Animais , Sinais (Psicologia) , Feminino , Odorantes , Percepção Olfatória/efeitos dos fármacos
17.
Animals (Basel) ; 10(7)2020 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-32709097

RESUMO

Human remains detection dogs (HRDDs) are powerful police assets to locate a corpse. However, the methods used to select and train them are as diverse as the number of countries with such a canine brigade. First, a survey sent to human remains searching brigades (Ncountries = 10; NBrigades = 16; NHandlers = 50; Nquestions = 9), to collect their working habits confirmed the lack of optimized selection and training procedures. Second, a literature review was performed in order to outline the strengths and shortcomings of HRDDs training. A comparison between the scientific knowledge and the common practices used by HRDDs brigade was then conducted focusing on HRDDs selection and training procedures. We highlighted that HRDD handlers select their dogs by focusing on behavioral traits while neglecting anatomical features, which have been shown to be important. Most HRDD handlers reported to use a reward-based training, which is in accordance with training literature for dogs. Training aids should be representative of the odor target to allow a dog to reach optimal performances. The survey highlighted the wide diversity of homemade training aids, and the need to optimize their composition. In the present document, key research topics to improve HRDD works are also provided.

18.
Insects ; 11(4)2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32290328

RESUMO

A cadaver is colonized by a wide diversity of necrophagous insects. It is well documented that Dipterans are attracted by the volatile organic compounds (VOCs) released by a corpse during the first minutes following death. Coleopterans are known to be attracted by highly decomposed cadavers, but have received less attention regarding the olfaction-based mechanisms underlying these interactions. In the present study, we impregnated gauzes with VOCs collected from each decomposition stage of dead rats: fresh, bloated, active, and advanced decay. We collected the VOCs released by the gauze and confirmed what was previously know from the literature: the decomposition stages are associated with contrasting chemical profiles. We exposed Dermestes frischii Kugelann (Coleoptera: Dermestidae) male and female antennae to the same gauzes and found that stronger electrical responses were recorded when using the smell of the advanced decay stage. Finally, we performed two choices behavioral assays. Females showed no preference for the four decomposition stages, while males were attracted by the smell associated with active and advanced decay stages. These results suggest that specific VOCs released by a decaying body guide necrophagous coleopterans to their feeding site. Whether D. frischii males release pheromones to attract females remains to be tested.

19.
Insects ; 11(7)2020 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-32664588

RESUMO

Aphids (Hemiptera: Aphididae) cause significant damage and transmit viruses to various crop plants. We aimed to evaluate how the infectious status of aphids influences their interaction with potential hosts. Two aphid (Myzus persicae and Rhopalosiphum padi) and plant (Nicotiana tabacum and Triticum aestivum) species were used. The preferences of aphids towards healthy, virus-infected (Potato Leafroll Virus (PLRV) and Barley Yellow Dwarf virus (BYDV)), and endophytic entomopathogenic fungi (EEPF)-inoculated (Beauveria bassiana and Metarhizium acridum) plants were investigated in dual-choice tests. The headspace volatiles of the different plant modalities were also sampled and analyzed. Viruliferous and non-viruliferous aphids were more attracted to EEPF-inoculated plants compared to uninoculated plants. However, viruliferous aphids were more attracted to EEPF-inoculated plants compared to virus-infected plants, while non-viruliferous insects exhibited no preference. Fungal-inoculated plants released higher amounts of aldehydes (i.e., heptanal, octanal, nonanal and decanal) compared to other plants, which might explain why viruliferous and non-viruliferous aphids were more abundant in EEPF-inoculated plants. Our study provides an interesting research perspective on how EEPF are involved in behavior of virus vector, depending on the infectious status of the latter.

20.
PLoS One ; 15(2): e0228817, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32032382

RESUMO

Abamectin is a common biocide used to control agricultural insect pests. However, the water insolubility of abamectin may result in extra organic solvent introduced in the environment. To solve this issue, it is desirable to develop nanoformulations to encapsulate abamectin with environment-friendly polymers. In this study, two polylactic acid based abamectin nanoformulations were prepared. The average particle sizes, measured by dynamic light scattering and transmission electron microscope, were 240 nm and 150 nm, respectively. The insecticidal activity of these nano-formulated abamectin was examined in the laboratory on the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae). The acute toxicity of nano-formulated abamectin on non-target aphid predator Adalia bipunctata (Coleoptera: Coccinellidae) was also evaluated by topical, residual and oral exposure. The two nano-formulated abamectin had comparable insecticidal effect with commercial abamectin formulation against the pea aphid. Taking median lethal concentration (LC50) as the toxicological endpoint, nanoformulations had higher contact toxicity and lower oral toxicity to first-instar larvae of the predator A. bipunctata. These results are expected to contribute to the application of solvent-free nano-formulated pesticides that comply with the integrated pest management (IPM) strategies.


Assuntos
Afídeos/efeitos dos fármacos , Besouros/efeitos dos fármacos , Inseticidas/toxicidade , Ivermectina/análogos & derivados , Nanoestruturas/química , Poliésteres/química , Animais , Afídeos/crescimento & desenvolvimento , Besouros/crescimento & desenvolvimento , Composição de Medicamentos , Inseticidas/química , Ivermectina/química , Ivermectina/toxicidade , Dose Letal Mediana , Tamanho da Partícula
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