Comportamento sexual de Rhodnius prolixus (Heteroptera: Reduviidae).

Submitted by Nuzia Santos ([email protected]) on 2017-08-24T18:12:29Z No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 2706332 bytes, checksum: 7221a4034541a3e6ae01bb82d4ee0d3a (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-08-24T18:18:34Z (GMT) No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 2706332 bytes, checksum: 7221a4034541a3e6ae01bb82d4ee0d3a (MD5)Made available in DSpace on 2017-08-24T18:18:35Z (GMT). No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 2706332 bytes, checksum: 7221a4034541a3e6ae01bb82d4ee0d3a (MD5) Previous issue date: 2010CAPES/MINCyTFAPEMIGCNPqFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.Este estudo descreveu a dinâmica de uso de abrigos em adultos de Rhodnius prolixus evidenciando que a saída dos abrigos e a atividade locomotora dos machos são moduladas por sinais olfativos sexuais emitidos por fêmeas. Adicionalmente, foram analisadas a frequência de início do vôo, e a atividade locomotora durante a marcha, a fim de avaliar as hipóteses de que haveri a ativação e orientação mediante sinais químicos emitidos por indivíduos do sexo opo sto. Além disso, verificamos o comportamento de agregação de machos ao redor de ca sais em cópula. Os odores das fêmeas foram capazes de induzir a saída dos mac hos dos abrigos, além de aumentar a atividade locomotora destes. Odores de f êmeas originados das glândulas metasternais promoveram um aumento na fre quência de inicio do voo de machos de R. prolixus. Além disso, estes sinais olfativos modularam a ori entação anemotática observada durante a marcha dos machos. Nossos achados demonstraram que na ausência dos odores das glândul as metasternais de fêmeas, o comportamento de agregação dos machos durante a c ópula é drasticamente afetado. Desta forma, concluímos que os odores prod uzidos pelas glândulas metasternais das fêmeas são de grande relevância no comportamento sexual de R. prolixus , já que na ausência destes, alguns mecanismos que medeiam o comportamento sexual desta espécie foram prejudicad os.This study described the dynamics of the use of she lters by adult Rhodnius prolixus showing that male activation in shelters and subseq uent locomotor activity are induzed by olfactory signals emitted by females. We analyzed both flight initiation frequency and orientation during locomotion, consid ering that insects should activate and engage in oriented responses if chemical signal s were emitted by individuals of the opposite sex. Furthermore, we evaluated the agg regation behavior of males to search for the source of the chemical signal. Femal e odors were able to induce males to leave their shelters and increased their l ocomotor activity. Female odors originated in metasternal glands promoted an increa se in take-off frequency in males. Moreover, these olfactory signals were also relevan t for the expression of an anemotactic response by walking males. Our findings suggest that in the absence of female metasternal gland odors, the aggregation beh avior of males during copulation is not expressed. Thus, we conclude that the odors produced by glands metasternal are a key set of signals mediating the sexual behav ior of R.prolixus

Sinais químicos envolvidos no comportamento sexual de Rhodnius prolixus Stål, 1859(Hemiptera, Reduviidae).

Submitted by Nuzia Santos ([email protected]) on 2017-08-24T18:01:23Z No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 697310 bytes, checksum: d325bade4e19e0adc49919cc0adfe30e (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-08-24T18:06:33Z (GMT) No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 697310 bytes, checksum: d325bade4e19e0adc49919cc0adfe30e (MD5)Made available in DSpace on 2017-08-24T18:06:33Z (GMT). No. of bitstreams: 1 Gina Barcelos Pontes.pdf: 697310 bytes, checksum: d325bade4e19e0adc49919cc0adfe30e (MD5) Previous issue date: 2007Instituto René RachouCAPESFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.Rhodnius prolixus é o principal vetor da doença de Chagas no norte da América do Sul e na América Central. Triatomí neos adultos possuem um par de glândulas metasternais (GM) localizadas no metatórax ventral. Alguns estudos discutem a participação das GMs na comunicação sexual em triatomíneos. Até o momento, a função das GMs de R. prolixus, assim como a identidade da suas secreções são desconhecidas. Assim, o objetivo deste estudo foi identificar os compostos presentes nas GMs de R. prolixus, bem como estudar o envolvimento destes compostos no contexto sexual desta espécie. Para isso, foram feitas análises químicas do conteúdo das GMs, utilizando SPME e CG-EM. Posteriormente, foram feitas análises químicas dos voláteis emitidos por casais em cópula. A emissão espontânea de voláteis em adultos virgens também foi caracterizada. Foram identificados 12 compostos nas GMs, sendo estes cetonas e álcoois. Os mesmos compostos foram encontrados nas glândulas de ambos os sexos. Em 70% das cópulas realizadas foi encontrado pelo menos um composto das GMs, sendo que o principal composto (2-metil-3-buten-2-ol) foi detectado em 40% das cópulas. As fêmeas emitiram espont aneamente mais compostos presentes nas GM durante a noite, sendo esta emissão mais intensa que nos machos. Propomos que os compostos encontrados nas GMs de R. prolixus estão envolvidos na comunicação sexual desta espécie. Foi observado um decréscimo no sucesso da cópula na ausência dos o dores das GMs devido a oclusão dos orifícios de abertura desta glândula. Sugerimos que o reconhecimento entre os sexos pode ser mediado por sinais químicos e que estes podem ser originados das GMs. A identificação dos compostos presentes nas GMs, assim como o envolvimento destes na comunicação química, é o primeiro passo no estudo dos prováveis feromônios sexuais de R. prolixus . A sua potencial utilização na manipulação do comportamento desta espécie justifica o aprofundamento deste estudo para permitir o desenho potencial de ferramentas para o seu controle.Twelve compounds produced by the metasternal glands (MGs) of the triatomine bug Rhodnius prolixus were identified by solid phase microextraction (SPME) combined with coupled gas chromatogra phy-mass spectrometry (GC-MS) using achiral and chiral columns. All substances were ketones or alcohols, and the same compound profile was found in the secretions produced by either sex. The most abundant compounds were 2-methyl-3-buten-2-ol, (2S)-pentanol, (3E)-2- methyl-3- penten-2-ol, and (2R/2S)-4-methyl-3-penten-2-ol. Emission of these compounds was detected more frequently from females than males, and females released them more frequently during the early hours of the scotophase, the period when sexual activity in this species is at its peak. These compounds were also detected in the headspace above mating pairs. Finally, the occlusion of the MG orifices of male or female bugs with paraffin resulted in a significant decrease in copulation frequency compared to sham-operated insects. Together, these data suggest that the MG secretions of R. proxilus may be involved in sexual communicatio

Salt controls feeding decisions in a blood-sucking insect

Salts are necessary for maintaining homeostatic conditions within the body of all living organisms. Like with all essential nutrients, deficient or excessive ingestion of salts can result in adverse health effects. The taste system is a primary sensory modality that helps animals to make adequate feeding decisions in terms of salt consumption. In this work we show that sodium and potassium chloride salts modulate the feeding behavior of Rhodnius prolixus in a concentration-dependent manner. Feeding is only triggered by an optimal concentration of any of these salts (0.1–0.15 M) and in presence of the phagostimulant ATP. Conversely, feeding solutions that do not contain salts or have a high-salt concentration (>0.3 M) are not ingested by insects. Notably, we show that feeding decisions of insects cannot be explained as an osmotic effect, because they still feed over hyperosmotic solutions bearing the optimal salt concentration. Insects perceive optimal-salt, no-salt and high-salt solutions as different gustatory information, as revealed the electromyogram recordings of the cibarial pump. Moreover, because insects do a continuous gustatory monitoring of the incoming food during feeding, sudden changes beyond the optimal sodium concentration decrease and even inhibit feeding. The administration of amiloride, a sodium channel blocker, noticeably reduces the ingestion of the optimal sodium solution but not of the optimal potassium solution. Salt detection seems to occur at least through two salt receptors, one amiloride-sensitive and another amiloride-insensitive. Our results confirm the importance of the gustatory system in R. prolixus, showing the relevant role that salts play on their feeding decisions.Fil: Barcelos Pontes, Gina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Pereira, Marcos H.. Universidade Federal do Minas Gerais; BrasilFil: Barrozo, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Female odours promote the activation of sheltered kissing bug Rhodnius prolixus males and modulate their orientation

The existence of a pheromone emitted during copulation has been reported for Rhodnius prolixus (Hemiptera: Reduviidae) Stål. Adults possess one pair of metasternal glands (MGs) from which female R. prolixus release volatiles mainly at night. We investigated whether these volatiles emitted by adult R. prolixus can modulate sexual-related behaviours of opposite and/or same sex individuals. We first used a shelter bioassay to test if adult activity patterns can be affected by chemical signals emitted by opposite sex conspecifics. We observed that males left the shelter more frequently in the presence of females, showing higher activity and an increase of intrasexual copulation attempts. Females showed no shelter-related activation in the presence of male odours. Second, we used a locomotion compensator device to investigate whether females or males show oriented responses to odours emitted by adults. We found that males oriented towards air currents carrying female odours but females did not orient towards odours emitted by adults. Finally, we observed that males oriented towards the female MG compounds. Thus, a volatile chemical signal emitted by females from their MGs promoted the activation of sheltered males and modulated orientation to air currents.Fil: Barcelos Pontes, Gina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentina. Instituto Rene Rachou; BrasilFil: Zacharias, Claudia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Manrique, Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lorenzo, Marcelo Gustavo. Instituto Rene Rachou; Brasi

Kissing bugs can generalize and discriminate between different bitter compounds

Animals make use of contact chemoreception structures to examine the quality of potential food sources. During this evaluation they can detect nutritious compounds that promote feeding and recognize toxins that trigger evasive behaviors. Although animals can easily distinguish between stimuli of different gustatory qualities (bitter, salty, sweet, etc.), their ability to discriminate between compounds of the same quality may be limited. Numerous plants produce alkaloids, compounds that elicit aversive behaviors in phytophagous insects and almost uniformly evoke a bitter taste for man. In hematophagous insects, however, the effect of feeding deterrent molecules has been barely studied. Recent studies showed that feeding in Rhodnius prolixus can be negatively modulated by the presence of alkaloids such as quinine (QUI) and caffeine (CAF), compounds that elicit similar aversive responses. Here, we applied associative and non-associative learning paradigms to examine under two behavioral contexts the ability of R. prolixus to distinguish, discriminate and/or generalize between these two bitter compounds, QUI and CAF. Our results show that bugs innately repelled by bitter compounds can change their behavior from avoidance to indifference or even to preference according to their previous experiences. After an aversive operant conditioning with QUI or CAF, R. prolixus modified its behavior in a direct but also in a cross-compound manner, suggesting the occurrence of a generalization process between these two alkaloids. Conversely, after a long pre-exposure to each alkaloid, bugs decreased their avoidance to the compound used during pre-exposure but still expressed an avoidance of the novel compound, proving that QUI and CAF are detected separately. Our results suggest that R. prolixus is able to discriminate between QUI and CAF, although after an associative conditioning they express a symmetrical cross-generalization. This kind of studies adds insight into the gustatory sense of a blood-sucking model but also into the learning abilities of hematophagous insects.Fil: Asparch, Yamila Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Barcelos Pontes, Gina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Masague, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Minoli, Sebastian Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Barrozo, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Bitter stimuli modulate the feeding decision of a blood-sucking insect via two sensory inputs

The gustatory system of animals is involved in food quality assessment and controls the feeding decision of an individual confronted with a potential alimentary source. Triatomines are haematophagous insects that feed on vertebrate blood. Once they reach a potential host, they walk over the host skin searching for an adequate site to pierce. Then, they insert their stylets and take a first sampling gorge to decide whether food is acceptable. Our work reveals that the presence of bitter compounds inhibits the feeding behavior of these bugs. Firstly, triatomines decreased their feeding behavior if substrates spread with quinine or caffeine were detected by external receptors localized exclusively in the antennae. Morphological inspections along with electrophysiological recordings revealed the existence of four gustatory sensilla located in the tip of the antenna that respond to both bitter tastants. The absence of these bitter detectors by antennal ablation reversed the observed feeding inhibition evoked by bitter compounds. Secondly, once triatomines pumped the first volume of food with bitter compounds (quinine, caffeine, berberine, salicin), a decrease in their feeding behavior was observed. Morphological inspections revealed the existence of eight gustatory sensilla located in the pharynx that might be responsible for the internal bitter detection. Finally, we found that a brief pre-exposure to bitter compounds negatively modulates the motivation of bugs to feed on an appetitive solution. Results presented here highlight the relevance of bitter taste perception in the modulation of the feeding behavior of a blood-sucking insect.Fil: Barcelos Pontes, Gina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Minoli, Sebastian Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Ortega Insaurralde, Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: De Brito Sanchez, Maria Gabriela. Université Paul Sabatier; FranciaFil: Barrozo, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; Argentin

Ecologia populacional de Goniosoma sp. (Arachnida, Opiliones, Gonyleptidae) em uma caverna ferruginosa do município de Ouro Preto, MG

This study aimed to verify the population size and to show possible allometric variations between individuals. A total of 167 individuals were observed, from witch 69 were males, 78 were females and 20 were immature. Parental care was observed during all the study. The females were always near their clutches that were laid on the walls of the cave. Six aggregations were observed. There was an average of 8,67 individuals per aggregation, and females were more common, representing 64,4% of the aggregated individuals. The operational sex ratio was 1:1,18. The species is trogloxen, leaving the cave regularly to feed in the nearest trees and rocky walls, and returning in the morning. A Principal Components Analysis (PCA) evidenced a sexual dimorphism in the sizes of the second leg and its femur, the males with average leg length of 123,47 mm and femur length of 38,39 mm and the females with average leg length of79,13 mm and femur length of 25,14 mm