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ResumenEl éxito de las interacciones parasitoide-hospedero está determinado por la conducta de búsqueda, reconocimiento, ataque y defensa que despliegan los participantes en dicha interacción. Para comprender los patrones comportamentales entre los fóridos parasitoides y su hospedero, Atta colombica, se realizaron observaciones en un fragmento de bosque en el departamento de Córdoba, con un esfuerzo muestral de 186 horas en tres nidos de esta. Se recolectaron fóridos, hormigas atacadas y la carga que llevaban. En total se capturaron 52 individuos de Eibesfeldtphora attae y 54 de Apocephalus colombicus. Se observaron diferencias en cuanto a la forma de ataque y el microhábitat preferido por los parasitoides. No hubo preferencia aparente por el tamaño de las hormigas que atacaron los fóridos, pero seleccionaron cargas de mayor tamaño para posarse sobre ellas. Cuando las hormigas respondieron al ataque, emplearon defensas individuales (adoptando posiciones o aumentando su velocidad) o grupales (cuando hormigas vecinas atacaban al parasitoide). Los fóridos parasitoides especializan su conducta con el fin de garantizar un ataque exitoso sobre su hospedero, quien responde modificando su comportamiento según el parasitoide atacante.
AbstractIn ecology, the success of parasitoid-host interactions is determined by the behavior of seeking, recognition, attack and defense deployed by the participants in the interaction. Our study aimed to understand the behavioral patterns between parasitoid phorids and their host Atta colombica from a forest fragment of Córdoba department, Colombia. We observed three nests of Atta colombica, from December 2013 to Januray 2015 (including dry and rainy seasons), for a total effort of 189 hours. We observed Phorids, their attacks to ants and collected their loads; we also considered differences in the way the parasitoids attacked and observed the microhabitat they preferred. A total of 52 individuals of Eibesfeldtphora attae and 54 of Apocephalus colombicus were collected. Apparently there was no preference for the size of the ants that were attacked by phorids, but larger loads were selected to land on them. When the ants responded to the phorid attack, they used individual defenses (adopting positions or increasing their speed) or grupal defenses (closer ants attacking the phorid). Parasitoid phorids have specialized their behavior, in order to ensure a successful attack on their host, who responded by modifying its behavior, according to the attacker (parasitoid).
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Studies were conducted to determine the selection of humans, chickens and rabbits by Culicidae in three different environments in the province of Chaco, Argentina. Mosquitoes were collected fortnightly using cylindrical metal traps containing animal bait (chickens and rabbits). The mosquitoes were collected between June 2001-May 2002. During the same period and with the same frequency, mosquitoes biting the human operators of the traps were collected during the first 15 min of exposure within different time intervals: from 09:00 am-11:00 am, 01:00 pm-03:00 pm, 05:00 pm-07:00 pm and 09:00 pm-10:00 pm. A total of 19,430 mosquitoes of 49 species belonging to 10 genera were collected. Culex species mainly selected chicken bait and Wyeomyia species selected rabbit bait. Ochlerotatus and Psorophora species were more abundant in rabbit-baited traps. Anopheles triannulatus, Coquillettidia nigricans, Ochlerotatus scapularis, Mansonia titillans and Psorophora albigenu showed a strong attraction for human bait. The Anopheles, Coquillettidia, Culex and Mansonia species were more active between 05:00 pm-09:00 pm, while Ochlerotatus, Psorophora, Haemagogus and Wyeomyia were most active from 09:00 am-07:00 pm. This study provides additional information about the biology and ecology of arbovirus vectors in Chaco.
Subject(s)
Animals , Female , Humans , Rabbits , Culicidae/physiology , Feeding Behavior/physiology , Argentina , Chickens , Culicidae/classification , SeasonsABSTRACT
Objective To investigate the geographical distribution and host selection of Leptotrombidium rubellum among different small mammal hosts in some areas of Yunnan province,China.Methods Field survey was carried out in 23 counties of Yunnan province between 2001 and 2011.Small mammal hosts were captured with mouse cages and traps with baits.Chigger mites on the surface of two auricles were scraped off by a bistoury,and then preserved in 70％ ethanol.Every specimen of the chigger mites on the slides was finally identified into species under a microscope.Some conventional statistical methods were adopted to calculate all the collected chigger mite species and the constituent ratios of L,.rubellum in different areas and on different hosts,with prevalence (P),mean intensity (MI) and mean abundance (MA) on different hosts calculated.Linear regression was used to analyze the relationship among P,MI and MA.Patch index (m*/m) was used to measure the spatial patterns of L.rubellum among different individuals of related small mammal hosts.Results A total of 108 480 chigger mites were collected from the body surface of all the captured small mammal hosts.All the collected chigger mites were identified as 3 subfamilies,24 genera and 234 species.Of the 234 species of chigger mites,654 individuals of L.rubellum were collected,only in 4 counties.The collected individuals of L.rubellum accounted for 0.603％ of the total mites (108 480 individuals).96.637％ of L.rubellum came from flatland areas and habitats while only 3.363％ of the L.rubellum were from the mountainous regions.The orderings of the hosts appeared as Rodentia and Insectivora harbored 96.296％ and 2.469％ respectively,of the collected while Lagomorpha and other orders there was no L rubellum found.Of 67 species (in 34 genera and 12 families of 5 orders),Rattus tanezumi (in genus Rattus and family Muridae of Rodentia)harbored 96.788％ of the collected L.rubellum with relatively low prevalence (P=3.776％) or mean intensity (MI=8.792 mites/per host),followed by Bandicota indica.Data from the patch index showed that L rubellum had an aggregated distribution pattern among different individuals of their hosts.Conclusion L.rubellum existed in Yunnan province with relatively rare numbers of the individuals.In Yunnan province,L.rubellum was mainly found in the flatland regions and habitats with relatively low altitude.L.rubellum could parasitize several different species of hosts with low host specificity,but it prefered to choose Rattus tanezumi and some other house-dwelling small mammals as its main hosts.
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Solenopsis saevissima (Smith) and Solenopsis invicta Buren are the most abundant and widely distributed fire ants in Brazil. The occurrence of the two fire ant species and of their parasitoids Pseudacteon spp. is described for a climatic and phytophysiognomic transition area in the state of São Paulo. Both fire ant species have a parapatric distribution, apparently determined by the climate: S. saevissima predominates in the north part of São Paulo (Aw climate), while S. invicta in the south (Cfa climate). A sympatric area is observed between the latitudes 21ºS and 23ºS. Two different communities of parasitic decapitating flies were associated with S. saevissima in the north and with S. invicta in the south, with a sympatric area in the municipality of São Carlos (21º58'S 47º53'W). The possible causes of this biogeographic pattern are discussed. Preference tests with Pseudacteon flies challenge the association of P. litoralis Borgmeier, P. curvatus Borgmeier, P. wasmanni Schmitz, P. pradei Borgmeier and P. obtusus Borgmeier with S. saevissima, and P. dentiger Borgmeier, P. disneyi Pesquero and P. lenkoi Borgmeier & Prado with S. invicta.
Subject(s)
Animals , Female , Male , Ants , Diptera , Animal Distribution , Brazil , GeographyABSTRACT
Objective To investigate the distribution of Leptotrombidium deliense among different small mammal hosts in some areas of Yunnan province. Methods A field survey was carried out in some counties of Yunnan province and the small mammal hosts were captured, using mouse cages and traps with baits. Chigger mites on the surface of two auricles were scraped off by a bistoury, and then preserved in 70% ethanol. Every specimen of the chigger mites on the slides was finally identified into species under a microscope. Some conventional statistical methods were adopted to calculate all the collected chigger mite species and the constituent ratios of Leptotrombidium deliense in different areas and on different hosts, together with its prevalence and mean abundance on different hosts. Results A total of 10 222 small mammal hosts were captured from 19 counties and identified as 11 families, 34 genera and 62 species in 5 orders, and 92 990 individuals of chigger mites were collected from the body surface of these small mammal hosts. All the collected chigger mites were identified as 3 subfamilies, 22 genera, and 225 species. Meanwhile, Leptotrombidium deliensee only accounted for 1.659% of the total. The host specificity of Leptotrombidium deliense was very low and 1544 individuals of Leptotrombidium deliense collected from 8518 small mammal hosts belonged to 6 families, 13 genera and 19 species in 3 orders. Our results showed that Leptotrombidium delienses were mainly collected from Insectivora and Rodentia. Leptotrombidium deliense had long been considered as the dominant species of chigger mites and the main vector of tsutsugamushi disease in Yunnan province of China, but our results seemed not thoroughly supporting this point of view. Conclusion Traditionally, Leptotrombidium deliense was the dominant species and the main vectors of scrub typhus in Yunnan province. However, based on our results, the above view might be true in some local places and the composition of chigger mites and the main vector of tautsugamushi disease might be different in regions and habitats in Yunnan province.
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The host selection for oviposition by Spodoptera frugiperda (J.E. Smith) among corn, millet, cotton and soybean, and its relationship with the biological characteristics were investigated. Free and non-choice tests for oviposition using plots containing five plants each, from each host in plastic greenhouse, resulted in similar oviposition preference among the host plants. In addition, selected biological characteristics of S. frugiperda were determined in the laboratory with larvae feeding on host leaves, and the combination of leaf and cotton boll. Neonate larvae exhibited low success of colonization on cotton boll compared to the leaves of all other hosts. Spodoptera frugiperda fed only on cotton bolls exhibited longer larval and pupal development, and longer adult life span; however with similar egg production. Larvae fed cotton leaves during six days and then transferred to cotton bolls, however, exhibited development and reproduction similar to those reared on corn or only on cotton leaves. Therefore, the variations on immature stages of S. frugiperda were not related with host selection for oviposition which was similar among the studied hosts. Based on our data, the millet as a winter, rotational, and cover crop is a potential host for S. frugiperda, while leaves and cotton bolls were diets of intermediate suitability as compared to corn and soybean leaves.
Subject(s)
Animals , Food Preferences , Host Specificity , Oviposition , Spodoptera/anatomy & histology , Spodoptera/physiology , Reproduction , Spodoptera/growth & developmentABSTRACT
Pattern of attack of a galling insect reveals an unexpected preference-performance linkage on medium-sized resources. The Plant Vigor Hypothesis (PVH) predicts oviposition preference and higher offspring performance on longer and fast-growing shoots, and although several studies have tested its predictions, long-term studies concerning the patterns of host selection by galling species are still lacking. The PVH was tested in this study using Bauhinia brevipes (Fabaceae) as the host of a leaf gall midge, Asphondylia microcapillata (Diptera, Cecidomyiidae) during three consecutive years. Shoots were collected from the same 80 plants between 2001 and 2003 and shoot length, number of healthy and galled leaves, gall number, and mortality factors were recorded. Nearly 600 galls were found on the 5,800 shoots collected. Medium-sized shoots supported from 46 to 70 percent of all galls, with greater gall survival rate in 2002 and 2003. A decrease in parasitism rate coupled with an increase in gall predation lead to a constant similar gall survivorship rate in all years (x = 22.7 percent). Although gall abundance varied among years (122 in 2001, 114 in 2002 and 359 in 2003) preference for longer shoots was not observed because the percentage of galled shoots and galled leaves were higher on medium shoot length classes in all years. The observed distribution of gall abundance and galled shoots were always greater than the expected distribution on medium shoot length classes. These findings do not support the PVH, and show that A. microcapillata can maximize the female preference and larval performance on medium-sized shoots of B. brevipes.
A Hipótese do Vigor de Plantas (HVP) prevê uma oviposição preferencial e alta performance da prole em ramos longos e de crescimento rápido da planta hospedeira. Embora diversos estudos tenham testado suas predições, estudos de longa duração focados no padrão de seleção de planta hospedeira por insetos galhadores ainda são escassos. A HVP foi testada neste estudo usando Bauhinia brevipes (Fabaceae) como planta hospedeira de uma galha foliar induzida por Asphondylia microcapillata (Diptera: Cecidomyiidae) por três anos consecutivos. Ramos foram coletados das mesmas 80 plantas entre 2001 e 2003 e o tamanho do ramo, número de ramos galhados e sadios, número de galhas e fatores de mortalidade foram registrados. Aproximadamente 600 galhas de A. microcapillata foram coletadas em 5.800 ramos de B. brevipes. Ramos médios suportaram entre 46 por cento e 70 por cento do total de galhas, e a taxa de sobrevivência das galhas foi maior em 2002 e 2003. Uma diminuição da taxa de parasitismo associada com um aumento da taxa de predação de galhas resultou em uma sobrevivência similar em todos os anos (x = 22,7 por cento). A abundância de galhas variou entre os anos (122 em 2001, 114 em 2002 e 359 em 2003). A preferência por ramos longos não foi observada porque a porcentagem de ramos galhados e folhas galhadas foram maiores em ramos de classes de tamanho intermediário por dois anos. A distribuição observada da abundância de galhas e ramos galhados foi sempre maior do que a distribuição esperada em classes de ramos médios. Estes resultados não suportam a HVP, e mostram que A. microcapillata pode maximizar a preferência da fêmea e a performance larval em ramos de tamanho médio de B. brevipes.
ABSTRACT
O percevejo marrom da soja, Euschistus heros (F.), pode atingir altas densidades em alguns locais. Além da soja, alimenta-se de outras plantas, mas pouco se sabe sobre seus hospedeiros alternativos no Rio Grande do Sul. Os objetivos deste estudo foram determinar os hospedeiros nativos utilizados por E. heros no Noroeste do Rio Grande do Sul e comparar seu desempenho quando alimentado com estes e com a soja. Os percevejos foram amostrados em plantas existentes em áreas internas e marginais de cultivos de soja, nas safras 2004/2005 e 2005/2006. Euchistus heros foi encontrado alimentando-se de sementes de Amaranthus retroflexus (Amaranthaceae) e de frutos de três Solanaceae, principalmente Vassobia breviflora. A sobrevivência dos imaturos alimentados com soja (86,7 por cento) e com V. breviflora (81,8 por cento) foi semelhante, mas ninfas alimentadas com A. retroflexus não atingiram o estágio adulto. O alimento das ninfas teve efeito significativo sobre o peso dos adultos, o qual foi maior para aquelas alimentadas com soja do que com V. breviflora . Por outro lado, a sobrevivência e longevidade dos adultos não diferiram significativamente. As fêmeas alimentadas com soja depositaram massas de ovos maiores do que aquelas alimentadas com V. breviflora, mas não houve efeito do hospedeiro no numero médio de massas de ovos depositado/fêmea.
The Neotropical brown stink bug Euschistus heros (F.) can reach high densities in some soybean areas in Brazil. Besides soybean, it also feeds on other plants, but little is known on the alternative hosts of E. heros in Rio Grande do Sul state. In this study, wild non-cultivated hosts of E. heros at Norwest of Rio Grande do Sul state were determined, and the E. heros performance was compared when fed on soybean and on wild hosts. Bugs were sought in plants located inside and on the edge of soybean fields during 2004/2005 and 2005/2006 seasons. Adults were recorded feeding on seeds of Amaranthus retroflexus (Amaranthaceae), and on fruits of three Solanaceae, mainly Vassobia breviflora. Immature survivorship on soybean (86.7 percent) and on V. breviflora (81.8 percent) was the same, but nymphs fed on A. retroflexus did not reach adulthood. The host plant used during immature development greatly affected adult weight, with V. breviflora yielding the heaviest adults; however, adult survivorship and longevity when fed on different host plants were the same. Females fed on soybean laid larger egg masses than those fed on V. breviflora , but the overall fecundity was not affected.
Subject(s)
Animals , Heteroptera/physiology , Plants/parasitology , BrazilABSTRACT
Avaliou-se a influência da face foliar, do comportamento geotrópico do inseto e do tipo de tricoma foliar sobre a oviposição de Bemisia tabaci (Genn.) biótipo B em folhas de tomateiro. Para avaliação desses efeitos foram realizados vários ensaios nos quais as fêmeas foram confinadas em caixas de acrílico. Folíolos de tomateiro foram fixados no topo e na base das caixas, de tal forma a permitir o acesso dos insetos às faces adaxial e abaxial de maneira isolada e concomitante (com e sem chance de escolha). Os insetos sempre depositaram maior número de ovos quando a superfície foliar se encontrava no topo da caixa e, de maneira geral, preferiram depositar seus ovos na face abaxial dos folíolos. Para avaliar o efeito do tipo de tricoma (glandular e não-glandular) sobre a oviposição de B. tabaci, a face abaxial dos folíolos de tomateiro foi oferecida a cerca de 30 fêmeas para oviposição em cada caixa de acrílico. Foram oferecidos folíolos previamente lavados com etanol a 70 por cento (de forma a eliminar os exsudatos glandulares) e sem lavagem prévia. A maior parte da oviposição ocorreu ao lado dos tricomas não-glandulares, demonstrando que o inseto discrimina o tipo de tricoma.
The objective of this work was to evaluate the influence of the leaf surface, the insect geotropic behavior and the type of foliar trichome on Bemisia tabaci (Genn.) biotype B oviposition on tomato leaves. Bemisia tabaci females were confined in acrylic boxes in which tomato leaflets were fixed at the bottom and top part of the boxes to allow insects to access the leaf surface to be tested (adaxial and/or abaxial) in both no-choice and free choice tests. Oviposition was always higher when the leaf was offered at the top of the box and preferably at the abaxial leaf surface. The effects of leaf trichomes (glandular and non glandular) on B. tabaci oviposition was evaluated by offering the abaxial surface of tomato leaflets to females after a 70 percent ethanol wash to remove glandular exsudates against a control treatment (without a ethanol wash). Oviposition was concentrated mostly near to non glandular trichomes, showing whitefly females can discriminate among the trichomes.
Subject(s)
Animals , Behavior, Animal , Hemiptera/anatomy & histology , Solanum lycopersicum/parasitology , Oviposition , Plant Leaves/parasitologyABSTRACT
A traça-do-tomateiro apresentou maior oviposição ao colonizar tomateiros cultivados em sistema convencional em relação ao orgânico em estudos prévios realizados no campo. Visando confirmar e entender o padrão observado no campo, aspectos bioecológicos como oviposição e mortalidade de imaturos foram comparados em condições semi-controladas de casa de vegetação com plantas cultivadas em vasos com solo proveniente do sistema orgânico e convencional. Adultos da traça-do-tomateiro foram liberados na casa de vegetação e após 24h, as plantas infestadas foram transferidas para outra casa de vegetação, para acompanhamento de coortes horizontais. Os ovos naturalmente depositados pela traça-do-tomateiro foram localizados na planta e demarcados. Em seguida, a folha foi ensacada. Diariamente as plantas foram observadas, registrando a fase de desenvolvimento do inseto e a ocorrência de morte, até que todos os insetos completassem seu ciclo de vida. A oviposição pela traça-do-tomateiro em plantas com solos oriundos do sistema convencional foi duas vezes maior do que em plantas com solos do sistema orgânico. A curva de sobrevivência da fase imatura e a tabela de vida da traça-do-tomateiro em casa de vegetação mostraram que a sobrevivência em plantas com solo orgânico e convencional não apresentaram diferenças. Assim as diferenças no comportamento de padrão de oviposição observadas a campo provavelmente não estão relacionadas com o desempenho da progênie e podem ser influenciado pelo ambiente proporcionado pelo sistema orgânico de produção.
The tomato pinworm presented higher oviposition when colonizing tomato plants cropped in conventional system than in organic system, in previous field studies. Aiming to confirm and to understand the observed pattern in the field, bioecological processes, such as oviposition and mortality of immatures, were compared on ploted plants in soil from organic and conventional systems in semi-controlled conditions of greenhouse. Tomato pinworm adults were released in the greenhouse, the infested plants were transfered to another greenhouse after 24h, to track horizontal cohort. Naturally deposited eggs were located, marked and the leaf was caged. Each plant was observed daily and development stage or death was registered until all individuals completed the life cycle or died. Oviposition by tomato pinworm was 2-fold higher in plants growing in soil from conventional system than from organic system. The survivorship curve of immatures and life table in the greenhouse showed that there was no difference in organic and conventional plants. Thus, the difference in the oviposition pattern observed in the field is not related to the progeny performance and can be influenced by the environment of organic tomato crop system.
ABSTRACT
This paper aimed to evaluate the stimuli that orient Gryon gallardoi females to the eggs of Spartocera dentiventris and allow their discrimination. Using a four-arm olfactometer connected to four odor sources - S. dentiventris eggs; hexane washed eggs; tobacco leaves; and tobacco leaves with eggs - the arrestment of female parasitoids with previous oviposition experience and without was individually verified. The time of permanence in each odor field was registered for a period of 15 minutes. Host discrimination, regarding age and previous parasitism, was tested using arenas, where females were exposed for 30 minutes, individually, to egg groups with different treatments. To evaluate age discrimination, three groups of eggs, previously washed with hexane, were employed in the following conditions: one day-old eggs; one-day brushed with 12-days-old egg extract; 12-days-old eggs with extract of one day-old eggs; and control (washed eggs, one day-old). The same procedure was done using five and eight days-old eggs jointly with control. Age-dependent egg discrimination was verified exposing four egg groups in the following treatments: parasitized, parasitized and washed with hexane, not parasitized, and not parasitized with extract of parasitized eggs. Olfactometer tests showed that inexperienced females remained more time next to tobacco leaves when compared to experienced ones. Experienced females responded to odors that emanated from eggs. Egg extracts did not promote age discrimination; however, non parasitized eggs, with extract of parasitized eggs were partially avoided. The results obtained indicate that G. gallardoi females might modify their responses upon contact with host. This fact suggests learning occurs; however, the acceptance and discrimination of host may be influenced by a complex array of stimuli, difficult to evaluate in isolation.
Este trabalho objetivou avaliar os estímulos que direcionam as fêmeas Gryon gallardoi aos ovos de Spartocera dentiventris e promovem discriminação deles. Através de um olfatômetro de quatro braços conectado a quatro fontes de odor (ovos de S. dentiventris não lavados, ovos lavados com hexano, folhas de fumo e folhas de fumo com ovos) verificou-se, individualmente, o arrestamento dos parasitóides, experientes em oviposição e não experientes, registrando-se o tempo de permanência em cada campo de odor por 15 minutos. Para avaliar a discriminação do hospedeiro, em relação à idade e parasitismo prévio, utilizaram-se arenas, onde as fêmeas foram expostas por 30 minutos, individualmente, a grupos de ovos com diferentes tratamentos. Para a avaliação da idade, utilizaram-se três grupos de ovos, lavados com hexano, nas seguintes condições: ovos de um dia de idade pincelados com extrato de ovos de 12 dias, ovos de 12 dias com extrato de ovos de um dia e controle (ovos lavados de um dia). O mesmo procedimento foi feito utilizando-se ovos de cinco e oito dias de idade, juntamente com o controle. A discriminação de ovos previamente parasitados foi verificada expondo quatro grupos de ovos com os seguintes tratamentos: parasitados, parasitados e lavados com hexano, não parasitados e não parasitados com extrato de ovos parasitados. Testes em olfatômetro demonstraram que as fêmeas inexperientes permaneceram mais tempo junto às folhas de fumo que as experientes. As fêmeas experientes responderam aos odores oriundos dos ovos. Os extratos de ovos não promoveram a discriminação da idade, porém ovos não parasitados, impregnados com extrato de parasitados, foram parcialmente evitados. Os resultados deste trabalho apontam que as fêmeas de G. gallardoi podem modificar suas respostas diante do contato prévio com o seu hospedeiro, sugerindo aprendizagem, porém a aceitação e a discriminação do hospedeiro podem ser influenciadas por uma complexa combinação de estímulos,...
Subject(s)
Animals , Female , Hemiptera/parasitology , Hymenoptera/physiology , Odorants , Ovum/parasitology , Host-Parasite Interactions , Hemiptera/growth & developmentABSTRACT
With the aid of scanning electron microscopy, the external morphology and distribution of the antennal sensilla were described for females of Gryon gallardoi (Bréthes), an egg-parasitoid of coreids. The geniculated and clavated antennae are composed of 12 antennomeres. Along the flagelum we registered dorsal glands and seven types of sensilla: papillary, chaetica of two sizes - long and short types, styloconic grooved-peg, sickle-shaped and trichodea with numerical and spatial variation among the flagellomeres. Functional aspects of the sensilla are discussed in the context of G. gallardoi antennal drumming behavior. Thus, the determination and the description pattern of antennal sensilla in G. gallardoi, in the present study, is an advance regarding the elucidation of the mechanisms involved in the host selection behavior of this species.
Usando a microscopia eletrônica de varredura, foram descritas e ilustradas a morfologia externa e a distribuição das sensilas antenais da fêmea de Gryon gallardoi (Bréthes), um importante parasitóide de ovos de coreídeos. As antenas são genículo-clavadas, dotadas de 12 antenômeros. Ao longo do flagelo, foram registradas glândulas dorsais e sete tipos de sensilas: papilárias, caéticas, de dois tamanhos - uma mais alongada e outra mais curta, estilocônicas, cavilhas, falciformes e tricóides, com variação numérica e espacial entre os flagelômeros. Aspectos referentes à função das sensilas, em associação ao comportamento de tamborilamento antenal de G. gallardoi são discutidos Assim, a descrição e a determinação do padrão de distribuição das sensilas antenais de G. gallardoi, no presente estudo, é um avanço no sentido de elucidar os mecanismos envolvidos nos comportamento de seleção de hospedeiros dessa espécie.
Subject(s)
Animals , Female , Hymenoptera/ultrastructure , Microscopy, Electron, ScanningABSTRACT
The efficiency of Xylella fastidiosa transmission by sharpshooters on citrus plants is low and varies with the vector species. The feeding behavior of the sharpshooter vector related to X. fastidiosa acquisition and inoculation is one of the probable conditioning factors in transmission efficiency. The objective of this study was to assess the behavior of two sharpshooter species, Dilobopterus costalimai Young and Oncometopia facialis (Signoret), in selection of citrus nursery trees and feeding places and to ascertain the influence of sprouting on plant attractiveness to the vectors. Free choice tests were performed with the two species in observation chambers (63 x 63 x 120 cm), releasing 40 individuals per chamber. The number of dead insects were assessed as well as those that chose, or not, one of the treatments, at 3, 15, 21, 24, 39, 45 and 48h after the release. For D. costalimai the leaves were important at the start of host selection, and were substituted over time by the secondary branch. D. costalimai preferred to stay on the secondary leaf nervures followed by the secondary branch. O. facialis showed no difference in preference for staying on the leaves (central and secondary nervures) and secondary branch on citrus plants, and this varied with the time of day. The presence of sprouting in the nursery trees increased the attractiveness of the plant to the two sharpshooter species raising the chances of X. fastidiosa acquisition or inoculation. So, control measures should be adopted against these insects in periods of greater vegetation in orange orchards.
A eficiência de transmissão de Xylella fastidiosa por cigarrinhas em citros é baixa e variável com a espécie vetora. O comportamento alimentar do vetor relacionado à aquisição e inoculação de X. fastidiosa é um dos prováveis fatores condicionantes da eficiência de transmissão. Assim, os objetivos desse trabalho foram avaliar o comportamento de duas espécies de cigarrinhas, Dilobopterus costalimai Young e Oncometopia facialis (Signoret), na seleção de mudas cítricas e de locais de alimentação e verificar a influência das brotações na atratividade aos vetores. Realizaram-se testes de livre escolha em câmaras de observação (63 x 63 x 120 cm) com as duas espécies, liberando-se 40 indivíduos por câmara. Avaliou-se o número de insetos mortos e que escolheram ou não um dos tratamentos, após 3, 15, 21, 24, 39, 45 e 48h da liberação. Para D. costalimai, as folhas foram importantes no início da seleção hospedeira, sendo substituídas com o passar do tempo pelo ramo secundário. D. costalimai preferiu pousar na nervura secundária da folha, seguida pelo ramo secundário. Para O. facialis não houve diferença na preferência para pouso entre folhas (nervura central e secundária) e ramos secundários das mudas cítricas, sendo esta variável com o horário do dia. Comprovou-se que a presença de brotação nas mudas aumenta a atratividade das plantas para as duas espécies de cigarrinhas, elevando as chances de aquisição ou inoculação de X. fastidiosa pelos vetores. Assim, sugere-se adotar medidas de controle desses insetos em períodos de maior vegetação dos pomares de laranja.