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1.
J Chem Ecol ; 47(7): 653-663, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34196858

RESUMO

Upon damage by herbivores, plants release herbivory-induced plant volatiles (HIPVs). To find their prey, the pest's natural enemies need to be fine-tuned to the composition of these volatiles. Whereas standard methods can be used in the identification and quantitation of HIPVs, more recently introduced techniques such as PTR-ToF-MS provide temporal patterns of the volatile release and detect additional compounds. In this study, we compared the volatile profile of apple trees infested with two aphid species, the green apple aphid Aphis pomi, and the rosy apple aphid Dysaphis plantaginea, by CLSA-GC-MS complemented by PTR-ToF-MS. Compounds commonly released in conjunction with both species include nonanal, decanal, methyl salicylate, geranyl acetone, (Z)-3-hexenyl acetate, (Z)-3-hexenyl butanoate, (Z)-3-hexenyl 2-methyl-butanoate, (E)-ß-caryophyllene, ß-bourbonene and (Z)-3-hexenyl benzoate. In addition, benzaldehyde and (E)-ß-farnesene were exclusively associated with A. pomi, whereas linalool, (E)-4,8-dimethyl-1,3,7-nonatriene were exclusively associated with D. plantaginea. PTR-ToF-MS additionally detected acetic acid (AA) and 2-phenylethanol (PET) in the blends of both trees attacked by aphid species. In the wind tunnel, the aphid predator, Chrysoperla carnea (Stephens), responded strongly to a blend of AA and PET, much stronger than to AA or PET alone. The addition of common and species-specific HIPVs did not increase the response to the binary blend of AA and PET. In our setup, two host-associated volatiles AA + PET appeared sufficient in the attraction of C. carnea. Our results also show the importance of combining complementary methods to decipher the odor profile associated with plants under pest attack and identify behaviourally active components for predators.


Assuntos
Afídeos/fisiologia , Malus/química , Compostos Orgânicos Voláteis/química , Ácido Acético/análise , Ácido Acético/farmacologia , Animais , Cromatografia Gasosa-Espectrometria de Massas , Herbivoria/efeitos dos fármacos , Malus/metabolismo , Álcool Feniletílico/análise , Folhas de Planta/química , Folhas de Planta/metabolismo , Comportamento Predatório/efeitos dos fármacos , Especificidade da Espécie , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/farmacologia
2.
Nat Commun ; 12(1): 2818, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33990556

RESUMO

The sex pheromone system of ~160,000 moth species acts as a powerful form of assortative mating whereby females attract conspecific males with a species-specific blend of volatile compounds. Understanding how female pheromone production and male preference coevolve to produce this diversity requires knowledge of the genes underlying change in both traits. In the European corn borer moth, pheromone blend variation is controlled by two alleles of an autosomal fatty-acyl reductase gene expressed in the female pheromone gland (pgFAR). Here we show that asymmetric male preference is controlled by cis-acting variation in a sex-linked transcription factor expressed in the developing male antenna, bric à brac (bab). A genome-wide association study of preference using pheromone-trapped males implicates variation in the 293 kb bab intron 1, rather than the coding sequence. Linkage disequilibrium between bab intron 1 and pgFAR further validates bab as the preference locus, and demonstrates that the two genes interact to contribute to assortative mating. Thus, lack of physical linkage is not a constraint for coevolutionary divergence of female pheromone production and male behavioral response genes, in contrast to what is often predicted by evolutionary theory.


Assuntos
Genes de Insetos , Mariposas/genética , Mariposas/fisiologia , Atrativos Sexuais/genética , Atrativos Sexuais/fisiologia , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Alelos , Animais , Evolução Molecular , Feminino , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Endogamia , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Desequilíbrio de Ligação , Masculino , Preferência de Acasalamento Animal/fisiologia , Polimorfismo Genético , Locos de Características Quantitativas , Recombinação Genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
3.
Sci Rep ; 11(1): 2690, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514782

RESUMO

African horticulture is seriously affected by fruit flies, both native and invasive. Novel sustainable control methods need testing against the backdrop of smallholder-dominated farming of Africa. We evaluated the potential of male-specific attractants (parapheromones) laced with insecticide to suppress the alien invasive Bactrocera dorsalis and native Ceratitis capitata. In large-scale guava, methyl-eugenol (ME)-bait stations combined with toxic protein baits suppressed B. dorsalis within 8 months but resulted in a resurgence of the displaced Ceratitis capitata. In smallholder farms, intervention using SPLAT-ME laced with spinosad was surprisingly unsuccessful. Subsequent mark-release-recapture experiments showed high dispersal rates of flies, covering many times a typical farm size, leading to a continuous influx of flies from surrounding areas. Several other factors important for intervention were evaluated. SPLAT-MAT-ME dollops remained attractive for over two weeks, although gradually becoming less attractive than fresh baits. Further, competitive displacement was observed: C. capitata selectively emerged from fruits in which B. dorsalis infestation was low. Finally, we evaluated whether ME could be combined with C. capitata male attractants [trimedlure (TML) and terpinyl acetate (TA)] without affecting attraction. Combining male lures did not affect catches directly, although at very high populations of B. dorsalis attracted to ME interfered with C. capitata trap entry. Although ME-based methods can effectively suppress B. dorsalis, they were not effective at single smallholder scale due to the high dispersive propensity of tephritids. Further, competitive release implies the need for a combination of lures and methods. These observations are important for developing control schemes tailored for African smallholder settings.


Assuntos
Ceratitis capitata/fisiologia , Fazendas , Espécies Introduzidas , Controle de Pragas , Feromônios/farmacologia , Animais , Etiópia , Feminino , Masculino
4.
Malar J ; 19(1): 318, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32873302

RESUMO

BACKGROUND: Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito's life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.) METHODS: In the laboratory and in large (80 m2) outdoor cages in Tanzania, nulliparous and parous A. gambiae s.s. were offered choices between a blend of human skin volatiles (Skin Lure), a blend of floral volatiles (Vectrax), or a combination thereof. The blends consisted of odours that induce distinct, non-overlapping activation patterns in the olfactory circuitry, in sensory neurons expressing olfactory receptors (ORs) and ionotropic receptors (IRs), respectively. Catches were compared between treatments. RESULTS: In the laboratory nulliparous and parous mosquitoes preferred skin odours and combinations thereof over floral odours. However, in semi-field settings nulliparous were significantly more caught with floral odours, whereas no differences were observed for parous females. Combining floral and human volatiles did not augment attractiveness. CONCLUSIONS: Nulliparous and parous A. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.


Assuntos
Anopheles/fisiologia , Quimiotaxia , Flores/química , Odorantes/análise , Pele/química , Compostos Orgânicos Voláteis/metabolismo , Animais , Comportamento Alimentar , Feminino , Humanos , Tanzânia
5.
Sci Rep ; 10(1): 6512, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32300184

RESUMO

Sustainable, low impact control methods, including mating disruption and microbial insecticides against L. botrana have been available for decades. Yet, successful implementation has been restricted to only a few grapevine districts in the world. A limiting factor is the lack of a female attractant to either monitor or control the damaging sex. Volatile attractants for both female and male insects can be used to assess when L. botrana populations exceed economic thresholds, and to decrease the use of synthetic pesticides within both conventional and pheromone programs. Rather than using host-plant volatiles, which are readily masked by background volatiles released by the main crop, we tested the attractiveness of volatiles that signify microbial breakdown and more likely stand out against the background odour. A two-component blend of 2-phenylethanol (2-PET) and acetic acid (AA) caught significant numbers of both sexes. Catches increased with AA and, to a minimal extent, 2-PET loads. However, a higher load of 2-PET also increased bycatches, especially of Lepidoptera and Neuroptera. Major (ethanol, ethyl acetate, 3-methyl-1-butanol) or minor (esters, aldehydes, alcohols and a ketone) fermentation volatiles, did surprisingly not improve the attraction of L. botrana compared to the binary blend of 2-PET and AA alone, but strongly increased bycatches. The most attractive lure may thus not be the best choice in terms of specificity. We suggest that future research papers always disclose all bycatches to permit evaluation of lures in terms of sustainability.


Assuntos
Lepidópteros/efeitos dos fármacos , Odorantes , Comportamento Sexual Animal/efeitos dos fármacos , Compostos Orgânicos Voláteis/farmacologia , Ácido Acético/química , Ácido Acético/farmacologia , Animais , Feminino , Humanos , Lepidópteros/patogenicidade , Lepidópteros/fisiologia , Masculino , Controle de Pragas , Praguicidas/química , Praguicidas/farmacologia , Álcool Feniletílico/química , Álcool Feniletílico/farmacologia , Feromônios/antagonistas & inibidores , Feromônios/metabolismo , Atrativos Sexuais/química , Atrativos Sexuais/farmacologia , Especificidade da Espécie , Vitis/parasitologia , Compostos Orgânicos Voláteis/química
6.
Malar J ; 19(1): 52, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000782

RESUMO

BACKGROUND: Zooprophylaxis is a technique in which blood-seeking vectors are diverted to non-host animals in order to lower blood-feeding rates on human hosts. The success of this technique depends on the host preference of the vector being targeted. The objective of this study was to evaluate the effect of L-lactic acid (Abate) to divert malaria mosquito, Anopheles gambiae from feeding on human host. METHODS: A 14-month-old female goat was treated with Abate, a formulation incorporating L-lactic acid into a slow-release matrix. This formulation was applied on the fur of the goat's back and neck. The treated animal was then presented to Anopheles gambiae sensu stricto (s.s.) as a prospective host in a semi-field environment ('mosquito sphere') together with either an untreated animal or a human. The number of mosquitoes caught to each host choice offered were compared. RESULTS: Goat treated with the L-lactic acid formulation successfully attracted An. gambiae at higher rates (70.2%) than the untreated ones (29.8%). Furthermore, An. gambiae s.s. were attracted to a treated goat at an equivalent degree (47.3%) as to their preferred human host (52.7%), even when the preferred host was present in the same environment. CONCLUSIONS: The findings indicate that human host-seeking mosquitoes can be diverted into feeding on non-preferred hosts despite the close proximity of their favoured host, hence reducing chances for the transmission of blood-borne parasites.


Assuntos
Anopheles/fisiologia , Inseticidas , Ácido Láctico , Malária/prevenção & controle , Mosquitos Vetores/fisiologia , Temefós , Animais , Comportamento Alimentar/efeitos dos fármacos , Feminino , Cabras , Humanos , Malária/transmissão , Coelhos
7.
PLoS One ; 14(12): e0226815, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31887129

RESUMO

Host seeking in the yellow fever mosquito, Aedes aegypti, and the African malaria mosquito, Anopheles coluzzii, relies on specific and generic host-derived odorants. Previous analyses indicate that the behavioral response of these species depends differentially on the presence of carbon dioxide (CO2) and other constituents in human breath for activation and attraction. In this study, we use a flight tube assay and electrophysiological analysis to assess the role of acetone, a major component of exhaled human breath, in modulating the behavioral and sensory neuronal response of these mosquito species, in the presence and absence of CO2. When presented alone at ecologically relevant concentrations, acetone increases attraction in Ae. aegypti, but not in An. coluzzii. Moreover, in combination with CO2, human breath-equivalents of acetone ranging between 0.1 and 10 ppm reproduces a behavioral response similar to that observed to human breath in host-seeking Ae. aegypti, but not in An. coluzzii. Acetone does, however, reduce attraction to CO2 in An. coluzzii, when presented at a higher concentration of 10 ppm. We identify the capitate peg A neuron of the maxillary palp of both species as a dual detector of CO2 and acetone. The sensory response to acetone, or binary blends of acetone and CO2, reflects the observed behavioral output in both Ae. aegypti and An. coluzzii. We conclude that host recognition is contextual and dependent on a combination of ecologically relevant odorants at naturally occurring concentrations that are encoded, in this case, by differences in the temporal structure of the neuronal response. This information should be considered when designing synthetic blends for that optimally attract mosquitoes for monitoring and control.


Assuntos
Acetona/farmacologia , Comportamento Animal/efeitos dos fármacos , Dióxido de Carbono/farmacologia , Culicidae/fisiologia , Olfato , Aedes/fisiologia , Animais , Anopheles/fisiologia , Expiração , Comportamento de Busca por Hospedeiro/efeitos dos fármacos , Humanos , Malária/transmissão , Odorantes , Febre Amarela/transmissão
8.
Prog Neurobiol ; 181: 101661, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31310789

RESUMO

The discovery of chemoreceptors and technological advances have greatly increased our understanding of chemosensory mechanisms. However, some of this rapid progress may have been severely compromised by insufficient attention given to the possible effects of impurities in the chemical standards used in identifying ligands for target receptors. Here, we show that even trace amounts of impurities in test stimuli can completely obscure true ligand-receptor relationships. Responses to impurities may go unrecognized because of two main factors. First, the sensitivity of receptors to ligands may be greater than that of the instruments used to check sample purity. Second, the concentrations of impurities actually reaching the chemoreceptor during experiments may be orders of magnitude higher than that of the putative stimulus, due to large differences in vapour pressure between the impurities and the putative stimulus. Errors caused by impurities are not limited to receptor-ligand studies, but can also affect related areas of chemosensory research, such as neural processing, downstream behaviours, and "in-silico" bioinformatics predictions of response profiles. The purity of standards is always implied but must be checked rigorously to prevent skewed or invalid results or conclusions, such as we exemplify here for Drosophila melanogaster and its olfactory receptor DmOr7a.


Assuntos
Neurofisiologia/métodos , Neurofisiologia/normas , Receptores Odorantes/análise , Animais , Cromatografia/métodos , Cromatografia/normas , Drosophila melanogaster , Reações Falso-Positivas
9.
Curr Opin Insect Sci ; 34: 105-111, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31247410

RESUMO

The proven ability of vector mosquitoes to adapt to various strategies developed to control them has enabled mosquito-borne diseases such as malaria, dengue, and lymphatic filariasis to remain entrenched as public health threats all over the world. Rather than continuing to seek a miracle cure for all mosquito vector problems among the ranks of single mode-of-action chemical pesticides, today's developers of vector control strategies are increasingly turning to more integrated, varied techniques, relying on pheromones and other semiochemicals to effect vector control through behavioral manipulation of the vector. Examples of this focus include attract-and-kill technologies utilizing floral odors and vertebrate host-associated scent cues to achieve control of adult mosquitoes, and selective oviposition attractants and larval phagostimulants to improve the efficacy of bacterial larvicides.


Assuntos
Controle de Mosquitos/métodos , Mosquitos Vetores , Odorantes , Animais
10.
Insects ; 10(1)2019 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-30621292

RESUMO

Upon herbivory, plants release herbivore-induced plant volatiles (HIPVs), which induce chemical defenses in the plant as well as recruit natural enemies. However, whether synthetic HIPVs can be employed to enhance biological control in a cultivated crop in the field is yet to be explored. Here we show that a biodegradable formulation loaded with induced and food-signaling volatiles can selectively recruit the common green lacewing, Chrysoperla carnea, and reduce pest population under field conditions. In apple orchards, the new formulation attracted lacewing adults over a 4-week period, which correlated well with independent assessments of the longevity of the slow-release matrix measured through chemical analyses. In barley, lacewing eggs and larvae were significantly more abundant in treated plots, whereas a significant reduction of two aphid species was measured (98.9% and 93.6% of population reduction, for Sitobion avenae and Rhopalosiphum padi, respectively). Results show the potential for semiochemical-based targeted recruitment of lacewings to enhance biological control of aphids in a field setting. Further research should enhance selective recruitment by rewarding attracted natural enemies and by optimizing the application technique.

11.
Ecol Lett ; 22(1): 108-118, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30370646

RESUMO

Tephritid flies are serious fruit pests. Despite clear niche differences, many species show considerable overlap in fruit preferences, of which we here analysed the olfactory correlate. Using the volatiles of four unrelated fruit species, antennal responses were quantified to construct a fruit-odour response database for four tephritid species. Although responses were distinct with a significant niche-correlated bias, the analyses show that the probability of detection of a volatile strongly increased with its sharedness across fruits. This also held for the unrelated fruit fly Drosophila melanogaster (DoOR repository-based analyses). We conjectured that shared volatiles signify 'host' to the fly 'nose' and induce attraction. Indeed, blends of volatiles shared by fruit and detected by all four species were very attractive for tephritid species, more than fruits. Quantitative whole antennal recordings en lieu of, or complementing bottom-up molecular neurogenetic approaches, enables comparative olfactomics in non-model species, and facilitate interpretation of olfaction in evolutionary, ecological, and applied contexts.


Assuntos
Drosophila melanogaster , Comportamento Alimentar , Animais , Frutas , Olfato
12.
Pest Manag Sci ; 75(6): 1671-1680, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30506833

RESUMO

BACKGROUND: Small-scale farmers often take a double hit from pests such as tephritid fruit-flies. The high price of products against fruit-flies, together with the higher risk of reinfestation from neighboring orchards, limits options for control. Therefore, management requires low-cost local products and concerted action. Peach production in central Bolivia is increasingly affected by invasive Ceratitis capitata. To provide locally sustainable techniques that could incentivize area-wide cooperation of growers, we tested efficiency and specificity of low-cost lures and traps compared with commercial lures and traps (Tephritrap). RESULTS: In the laboratory, the local fermented beverage 'chicha' and baker's yeast were equally or more attractive than commercial lures. Both chicha and baker's yeast trapped more flies in field (average FTD 10.31 and 9.49), whereas commercially hydrolyzed protein lure (4.71) or Torula yeast (6.82). However, many non-target species were caught (57.3% and 53.4%). Of the six PET bottles-based traps used, the T-trap caught a similar number of flies (average FTD 5.55), but fewer beneficial insects (0.16) compared to the Tephritrap (0.92). CONCLUSIONS: This study provides fruit growers with an economical and effective method to capture large numbers of C. capitata, suitable to be part of integrated pest management programs for fruit fly control. © 2018 Society of Chemical Industry.


Assuntos
Ceratitis capitata , Controle de Insetos/métodos , Animais , Bioensaio , Espécies Introduzidas , Desenvolvimento Sustentável
13.
Insects ; 9(3)2018 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-30223498

RESUMO

Tephritid fruit flies require protein for sexual and gonotrophic development. Food-based lures are therefore widely used in strategies to detect and control fruit flies in the Tephritidae family. However, these baits are attractive to a broad range of insect species. We therefore sought to identify volatiles detected by the fly antennae, with the goal to compose lures that more specifically target tephritids. Using gas chromatography-coupled electroantennographic detection (GC-EAD) we screened for antennal responses of four important tephritid species to volatile compounds from five commercially available protein-based baits. Antennal active compounds were reconstituted in synthetic blends for each species and used in behavioral assays. These species-based blends were attractive in olfactometer experiments, as was a blend composed of all antennally active compounds from all the four species we observed (tested only in Bactrocera dorsalis, Hendel). Pilot field tests indicate that the blends need to be further evaluated and optimized under field conditions.

14.
R Soc Open Sci ; 4(5): 170189, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28573028

RESUMO

Natural selection has favoured specialization in anthropophilic mosquito host choice, yet in the absence of human hosts, females feed on a selected range of vertebrates. For host recognition, we hypothesize that mosquitoes primarily rely on generic host volatiles. Detection and perception of such compounds would provide the mosquito with a flexible, yet constrained, odour coding system that could delineate host preference. In this study, we show that the quintessential generic volatile for host-seeking, carbon dioxide, activates and attracts the malaria mosquito, Anopheles coluzzii, and the arbovirus vectors, Aedes aegypti and Culex quinquefasciatus, within boundaries set by the dynamic range and coding capacity of the CO2-sensitive olfactory receptor neurons. These boundaries are sufficiently broad to elicit behavioural responses to various hosts within their preferred host range. This study highlights the significance of the sensitivity of the carbon dioxide detection system and its regulation of host seeking and recognition.

15.
PLoS Negl Trop Dis ; 10(10): e0005043, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27768698

RESUMO

BACKGROUND: There is a global need for cost-effective and environmentally friendly tools for control of mosquitoes and mosquito-borne diseases. One potential way to achieve this is to combine already available tools to gain synergistic effects to reduce vector mosquito populations. Another possible way to improve mosquito control is to extend the active period of a given control agent, enabling less frequent applications and consequently, more efficient and longer lasting vector population suppression. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the potential of biodegradable wax emulsions to improve the performance of semiochemical attractants for gravid female culicine vectors of disease, as well as to achieve more effective control of their aquatic larval offspring. As an attractant for gravid females, we selected acetoxy hexadecanolide (AHD), the Culex oviposition pheromone. As toxicant for mosquito larvae, we chose the biological larvicides Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus (Bs). These attractant and larvicidal agents were incorporated, separately and in combination, into a biodegradable wax emulsion, a commercially available product called SPLAT (Specialized Pheromone & Lure Application Technology) and SPLATbac, which contains 8.33% Bti and 8.33% Bs. Wax emulsions were applied to water surfaces as buoyant pellets of 20 mg each. Dose-mortality analyses of Culex quinquefasciatus Say larvae demonstrated that a single 20 mg pellet of a 10-1 dilution of SPLATbac in a larval tray containing 1 L of water caused 100% mortality of neonate (1st instar) larvae for at least five weeks after application. Mortality of 3rd instar larvae remained equally high with SPLATbac dilutions down to 10-2 for over two weeks post application. Subsequently, AHD was added to SPLAT (emulsion only, without Bs or Bti) to attract gravid females (SPLATahd), or together with biological larvicides to attract ovipositing females and kill emerging larvae (SPLATbacAHD, 10-1 dilution) in both laboratory and semi-field settings. The formulations containing AHD, irrespective of presence of larvicides, were strongly preferred as an oviposition substrate by gravid female mosquitoes over controls for more than two weeks post application. Experiments conducted under semi-field settings (large screened greenhouse, emulating field conditions) confirmed the results obtained in the laboratory. The combination of attractant and larvicidal agents in a single formulation resulted in a substantial increase in larval mosquito mortality when compared to formulations containing the larvicide agents alone. CONCLUSIONS/SIGNIFICANCE: Collectively, our data demonstrate the potential for the effective use of wax emulsions as slow release matrices for mosquito attractants and control agents. The results indicate that the combination of an oviposition attractant with larvicides could synergize the control of mosquito disease vectors, specifically Cx. quinquefasciatus, a nuisance pest and circumtropical vector of lymphatic filariasis and encephalitis.


Assuntos
Inseticidas/farmacologia , Larva/microbiologia , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Controle Biológico de Vetores/métodos , Feromônios/farmacologia , Animais , Bacillus thuringiensis/fisiologia , Feminino , Masculino , Controle de Mosquitos/instrumentação , Mosquitos Vetores/microbiologia , Mosquitos Vetores/fisiologia , Oviposição/efeitos dos fármacos , Controle Biológico de Vetores/instrumentação
16.
Proc Natl Acad Sci U S A ; 113(42): E6401-E6408, 2016 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-27698145

RESUMO

The sexual pheromone communication system of moths is a model system for studies of the evolution of reproductive isolation. Females emit a blend of volatile components that males detect at a distance. Species differences in female pheromone composition and male response directly reinforce reproductive isolation in nature, because even slight variations in the species-specific pheromone blend are usually rejected by the male. The mechanisms by which a new pheromone signal-response system could evolve are enigmatic, because any deviation from the optimally attractive blend should be selected against. Here we investigate the genetic mechanisms enabling a switch in male response. We used a quantitative trait locus-mapping approach to identify the genetic basis of male response in the two pheromone races of the European corn borer, Ostrinia nubilalis Male response to a 99:1 vs. a 3:97 ratio of the E and Z isomers of the female pheromone is governed by a single, sex-linked locus. We found that the chromosomal region most tightly linked to this locus contains genes involved in neurogenesis but, in accordance with an earlier study, does not contain the odorant receptors expressed in the male antenna that detect the pheromone. This finding implies that differences in the development of neuronal pathways conveying information from the antenna, not differences in pheromone detection by the odorant receptors, are primarily responsible for the behavioral response differences among the males in this system. Comparison with other moth species reveals a previously unexplored mechanism by which male pheromone response can change in evolution.


Assuntos
Mapeamento Cromossômico , Genes de Insetos , Estudos de Associação Genética , Mariposas/fisiologia , Neurogênese/genética , Feromônios , Análise de Variância , Animais , Comportamento Animal , Cruzamentos Genéticos , Feminino , Ligação Genética , Escore Lod , Masculino , Locos de Características Quantitativas , Atrativos Sexuais
17.
J Chem Ecol ; 42(9): 931-940, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27586434

RESUMO

Frugivorous tephritid fruit flies have lineages with high levels of host generalism. These insects use olfaction to locate fruits, but how they are able to recognize the odors of so many different host species is poorly understood. We used a series of behavioral experiments to investigate the role of fruit ripening volatiles as host cues in the Queensland fruit fly, Bactrocera tryoni (Froggatt), a polyphagous pest in Australia. Odors of mature guava (Psidium guajava) attracted female and male flies more strongly than three other ripening stages and guava pulp. We analyzed volatiles from guava odor and selected eleven compounds, all of which elicited an electrophysiological response in the antenna of female flies. Three of these, ethyl acetate, ethyl butyrate, and ethyl propionate, were released at the highest rates from the most attractive ripening stage. In behavioral trials, these three esters were not attractive individually, whereas a combination was necessary and sufficient in attracting female flies. The three-component blend was as attractive as the entire 11-component blend, which without these key volatiles was not attractive. Moreover, injecting low ranking hosts (squash and cucumber) with the three volatiles increased attraction in ovipositing female flies. These fruit flies are classed as generalists, but like many polyphagous insects they could be regarded as resource specialists, preferring specific plant reproductive stages with predictable odor cues. Exploring olfaction from this perspective could improve our understanding of host choice in polyphagous insects, and the selection of volatiles to be used as attractants in insect pest management.


Assuntos
Controle de Insetos , Odorantes/análise , Psidium/química , Tephritidae/fisiologia , Compostos Orgânicos Voláteis/análise , Animais , Feminino , Frutas/química , Frutas/parasitologia , Frutas/fisiologia , Controle de Insetos/métodos , Masculino , Oviposição , Psidium/parasitologia , Psidium/fisiologia , Olfato , Tephritidae/anatomia & histologia , Compostos Orgânicos Voláteis/metabolismo
18.
Genome Biol Evol ; 8(8): 2297-311, 2016 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-27435796

RESUMO

How the evolution of olfactory genes correlates with adaption to new ecological niches is still a debated topic. We explored this issue in Drosophila suzukii, an emerging model that reproduces on fresh fruit rather than in fermenting substrates like most other Drosophila We first annotated the repertoire of odorant receptors (ORs), odorant binding proteins (OBPs), and antennal ionotropic receptors (aIRs) in the genomes of two strains of D. suzukii and of its close relative Drosophila biarmipes We then analyzed these genes on the phylogeny of 14 Drosophila species: whereas ORs and OBPs are characterized by higher turnover rates in some lineages including D. suzukii, aIRs are conserved throughout the genus. Drosophila suzukii is further characterized by a non-random distribution of OR turnover on the gene phylogeny, consistent with a change in selective pressures. In D. suzukii, we found duplications and signs of positive selection in ORs with affinity for short-chain esters, and loss of function of ORs with affinity for volatiles produced during fermentation. These receptors-Or85a and Or22a-are characterized by divergent alleles in the European and American genomes, and we hypothesize that they may have been replaced by some of the duplicated ORs in corresponding neurons, a hypothesis reciprocally confirmed by electrophysiological recordings. Our study quantifies the evolution of olfactory genes in Drosophila and reveals an array of genomic events that can be associated with the ecological adaptations of D. suzukii.


Assuntos
Adaptação Fisiológica , Proteínas de Drosophila/genética , Drosophila/genética , Evolução Molecular , Receptores Odorantes/genética , Animais , Drosophila/classificação , Proteínas de Drosophila/metabolismo , Genoma de Inseto , Família Multigênica , Filogenia , Receptores Odorantes/metabolismo , Seleção Genética
19.
Annu Rev Entomol ; 61: 99-117, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26565898

RESUMO

Moth sexual pheromones are widely studied as a fine-tuned system of intraspecific sexual communication that reinforces interspecific reproductive isolation. However, their evolution poses a dilemma: How can the female pheromone and male preference simultaneously change to create a new pattern of species-specific attraction? Solving this puzzle requires us to identify the genes underlying intraspecific variation in signals and responses and to understand the evolutionary mechanisms responsible for their interspecific divergence. Candidate gene approaches and functional analyses have yielded insights into large families of biosynthetic enzymes and pheromone receptors, although the factors controlling their expression remain largely unexplored. Intra- and interspecific crosses have provided tantalizing evidence of regulatory genes, although, to date, mapping resolution has been insufficient to identify them. Recent advances in high-throughput genome and transcriptome sequencing, together with established techniques, have great potential to help scientists identify the specific genetic changes underlying divergence and resolve the mystery of how moth sexual communication systems evolve.


Assuntos
Evolução Biológica , Proteínas de Insetos/genética , Mariposas/fisiologia , Atrativos Sexuais/genética , Animais , Feminino , Proteínas de Insetos/metabolismo , Masculino , Mariposas/genética , Atrativos Sexuais/metabolismo , Especificidade da Espécie
20.
J Chem Ecol ; 41(11): 997-1005, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26489833

RESUMO

The European corn borer (ECB) is an important pest of maize in the northern hemisphere, but no reliable techniques exist for monitoring females during their reproductive period. In this study, we aimed to identify host-plant volatiles used by gravid Z-strain females in search for oviposition sites. Headspace of maize plants, to which gravid females orientated in a wind tunnel, was collected, and physiologically-active components were identified by using gas chromatography (GC) coupled with electroantennographic detection followed by GC-mass spectrometry. The antennae of female moths consistently responded to two maize volatiles, nonanal and decanal. Although these compounds are individually not characteristic for maize, a synthetic mix in a ratio found in maize headspace, 1:2.4 at 1 µg µl(-1) induced source contact and landing responses similar to maize plants in the wind tunnel. However, fewer females took flight in response to the mix, and those that took flight did so with an increased latency. To our knowledge, this is the first blend of host-plant volatiles that has been found to be physiologically active and to be able to induce attraction of gravid ECB females under laboratory conditions. Future tests will evaluate the attractiveness of the blend to the E-strain of ECB, the attractiveness of the blend in the field, and its potential in monitoring ECB populations.


Assuntos
Antenas de Artrópodes/fisiologia , Mariposas/fisiologia , Oviposição , Compostos Orgânicos Voláteis/metabolismo , Zea mays/química , Animais , Fenômenos Eletrofisiológicos , Feminino , Cromatografia Gasosa-Espectrometria de Massas
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