Showing papers in "Neotropical Entomology in 2008"
TL;DR: The bacterial community associated with the midgut of three Brazilian Lutzomyia longipalpis populations, two from endemic areas for visceral leishmaniasis and one from a non-endemic area, was identified.
Abstract: The bacterial community associated with the midgut of three Brazilian Lutzomyia longipalpis (Lutz & Neiva) populations, two from endemic areas for visceral leishmaniasis (Jacobina, Bahia State and Sao Luis, Maranhao State) and one from a non-endemic area (Lapinha Cave, Minas Gerais State), was identified Five groups, 35 females each, from each population were separated; a total of 175 females per collecting area were analyzed The species identification was based on molecular and traditional bacteriological methods All bacteria were either affiliated to non-Enterobacteriaceae, such as Acinetobacter, Burkholderia, Flavimonas, Pseudomonas and Stenotrophomonas, or and to Enterobacteriaceae, such as Citrobacter, Enterobacter, Escherichia, Klebsiella, Serratia, Pantoea, Morganella and Weeksella Stenotrophomonas was found to be associated with all three populations studied In addition, Serratia spp, which are well documented as laboratory contaminant of insects, were detected only in the Jacobina population We also discuss the impact of the colonization of insect gut by bacteria on the development and transmission of pathogens
90 citations
TL;DR: Advances obtained on the behaviour and identification of sex and defensive compound of stink bugs from Brazilian crops and the application of this knowledge to manage the stink bugs are discussed.
Abstract: In recent years the growing concern about environmental changes and how we are using the natural resources have triggered a search for natural products as alternatives to synthetic pesticides. The stink bugs produce a wide variety of chemical compounds (semiochemicals) that show potential to manage these insects. The stink bugs Chinavia impicticornis (Stal), C. ubica (Rolston), Dichelops melacanthus (Dallas), Euschistus heros (F.), Piezodorus guildinii (Westwood), Thyanta perditor (Westwood) and Tibraca limbativentris (Stal) had their blends of defensive compounds evaluated both qualitative and quantitatively. The main compounds identified on the glands of Brazilian stink bugs are: 2-alkenals, mainly the E isomer; saturated aliphatic hydrocarbons; and 4 oxo-(E)-2-alkenals. The first sex attractant determined from a stink bug was obtained from Nezara viridula L., and consists on a mix of two isomers cis - and trans bisabolene-epoxides. Later the soybean stink bug E. heros was also studied and its sex attractant was identified as three esters methyl: 2,6,10-trimethyldecanoate, methyl 2,6,10-trimethyldodecanoate, and methyl E2, Z4-decadienoate. Recently, three new Brazilian sting bugs were studied and had their sex attractant elucidated. Males of T. perditor produce the ester, methyl 2E,4Z,6Z-decatrienoate. Whereas, the stink bug, P. guildinii has as sexual pheromone, the sesquiterpene β-sesquiphellandrene, and the stink bug T. limbativentris produces as sex attractant the zingiberenol. In this review we discuss the advances obtained on the behaviour and identification of sex and defensive compound of stink bugs from Brazilian crops and the application of this knowledge to manage the stink bugs.
87 citations
TL;DR: The Ants of the Leaf-Litter (ALL) Sampling Protocol appear to be an adequate protocol for sampling ants in the highly-threatened Brazilian cerrado biome.
Abstract: Few studies have evaluated the efficiency of methods for sampling ants, especially in regions with highly variable vegetation physiognomies such as the Cerrado region of central Brazil. Here we compared three methods to collect ground-dwelling ants: pitfall traps, sardine baits, and the Winkler litter extractor. Our aim was to determine which method would be most appropriate to characterize the ant assemblages inhabiting different vegetation types. More species were collected with pitfall traps and with the Winkler extractor than with sardine baits. Pitfall traps collected more species in the cerrado (savanna) physiognomies, particularly in those with a poor litter cover, whereas the Winlker extractor was more efficient in the forest physiognomies, except the one subject to periodic inundations. There was a low similarity in species composition between forest and cerrado physiognomies, and this pattern was detected regardless of the method used to sampling ants. Therefore, even the use of a single, relatively selective method of collection can be enough for studies comparing highly distinct habitats and/or conditions. However, if the purpose of the sampling is to produce a more thoroughly inventory of the ant fauna, we suggest the use of a combination of methods, particularly pitfall traps and the Winkler extractor. Therefore, the Ants of the Leaf-Litter (ALL) Sampling Protocol appear to be an adequate protocol for sampling ants in the highly-threatened Brazilian cerrado biome.
85 citations
TL;DR: It is shown that the rate of publication on IIVs has slowed from 1990 to the present, and a number of conclusions and suggestions from the host list are drawn and recommendations for future research efforts are made.
Abstract: Invertebrate iridescent viruses (IIVs) are icosahedral DNA viruses that infect invertebrates, mainly insects and terrestrial isopods, in damp and aquatic habitats. Exhaustive searches of databases resulted in the identification of 79 articles reporting 108 invertebrate species naturally infected by confirmed or putative iridoviruses. Of these, 103 (95%) were arthropods and the remainder were molluscs, an annelid worm and a nematode. Nine species were from marine habitats. Of the 99 non-marine species, 49 were from terrestrial habitats and 50 were aquatic, especially the aquatic stages of Diptera (44 species). The abundance of records from species of Aedes,Ochlerotatus and Psorophora contrasts markedly with a paucity of records from species of Anopheles,Culex and Culiseta. Records from terrestrial isopods are numerous (19 species), although the diversity of IIVs that infect them is mostly unstudied. IIV infections have been reported from every continent, except Antarctica, but there are few records from Africa, southern Asia and Latin America. Most reports describe patent IIV infections as rare whereas inapparent (covert) infection may be common in certain species. The relationship between particle size and iridescent colour of the host is found to be consistent with optical theory in the great majority of cases. Only 24 reported IIVs from insect hosts have partial characterization data and only two have been subjected to complete genome sequencing. I show that the rate of publication on IIVs has slowed from 1990 to the present, and I draw a number of conclusions and suggestions from the host list and make recommendations for future research efforts.
81 citations
TL;DR: The presence of the red palm mite, Raoiella indica Hirst is recorded for the first time in South America.
Abstract: The presence of the red palm mite, Raoiella indica Hirst is recorded for the first time in South America. High populations and severe damages caused by this new invasive mite were found on coconut and banana leaves in Sucre (10° 27' 47" N and 64°10' 38" W) and Monagas (9o46'60" N and 63o12'0" W) states in northeastern Venezuela.
65 citations
TL;DR: Great dominance of Euglosssa cordata (L.) was observed in the sub-area burned and of Eulaema nigrita Lepeletier in Mata do Funil; both species were favored for open or disturbed environments.
Abstract: This work aimed at describing and analyzing structural and temporal parameters of communities of Euglossina in remnants of lowland forest on tertiary tabuleiro in the north Rio de Janeiro state in areas with different conservation status and anthropic influences. Chemical bait traps were installed from November/04 to November/05, from 8 am to 3 pm, in two sub-areas (burned and preserved) of Mata do Carvao (1053 ha) and Mata do Funil (135 ha). We collected 2,060 individuals of 11 species distributed in three genera in the burned sub-area, 894 individuals of nine species and three genera in the preserved sub-area and 1,115 individuals of 10 species distributed in four genera in Mata do Funil. The composition of species did not differ among the areas (MRPP, A = -0.015; P = 0.71). The diversity (H) obtained in the sub-area burned (H = 1.14) and preserved (H = 1.12) was significantly higher than that described for Mata do Funil (H = 0.98). Two peaks of abundance were observed, the larger one in the dry season. Great dominance of Euglosssa cordata (L.) (d = 0, 54) was observed in the sub-area burned and of Eulaema nigrita Lepeletier (d = 0, 55) in Mata do Funil; both species were favored for open or disturbed environments. The smaller fragment presented the lowest value of diversity, suggesting the effect of the lost of area on the community of Euglossina. Moreover, disturbed areas (burned) can be benefited if in connection with areas in better preservation condition.
60 citations
TL;DR: No significant correlations were observed between the levels of abiotic factors and the population levels of A. guerreronis or of the phytoseiids associated with it, and this probably occurred due to the simultaneous and conflicting effects of those factors on the mites in the field, or to significant differences between the climatic factors measured in the environment and those prevailing in the habitat occupied by A.
Abstract: Aceria guerreronis Keifer can cause severe damage to coconuts in several countries around the world. Rare studies have been conducted to determine the predatory mites associated with A. guerreronis in Brazil. The study evaluated the prevalence of A. guerreronis and associated predators on the bracts and on the surface of the fruits underneath the bracts, for 12 months, on coconut palms grown along the coast of the States of Alagoas, Paraiba and Pernambuco, Northeastern Brazil. Mites of 10 families were found, but by far the most abundant species was A. guerreronis, corresponding to 99.5% of the mites collected. The prevailing species amongst the predators were the Phytoseiidae mites Neoseiulus baraki (Athias-Henriot) and Neoseiulus paspalivorus (De Leon). These are flat mites that have short limbs, characteristics that allow them to invade the main habitat occupied by A. guerreronis. Other predators were found, but in low numbers, due mainly to their difficulty in reaching the fruit areas most inhabited by A. guerreronis. However, these mites could prey on that pest when it leaves its preferred habitat to disperse. No significant correlations were observed between the levels of abiotic factors and the population levels of A. guerreronis or of the phytoseiids associated with it. This probably occurred due to the simultaneous and conflicting effects of those factors on the mites in the field, or to significant differences between the climatic factors measured in the environment and those prevailing in the habitat occupied by A. guerreronis.
55 citations
TL;DR: The three most frequent species have been implicated in transmission of tegumentary leishmaniasis in Parana and in the Brazilian Southeastern and Southern Regions and the need to investigate its behavior, including as regard to the vectorial competence is investigated.
Abstract: Devido a crescente expansao da leishmaniose visceral americana (LVA) no Brasil, o presente estudo teve como objetivo identificar as especies de flebotomineos em areas vulneraveis a transmissao dessa parasitose, bem como em outras sem qualquer informacao sobre a presenca desses dipteros no Parana. As coletas de flebotomineos foram realizadas em 46 localidades distribuidas em 37 municipios do Parana, no periodo de marco de 2004 a novembro de 2005. Em cada uma das localidades foram instaladas armadilhas de Falcao, durante tres noites consecutivas, em vegetacao natural e ambientes antropicos (intra e peridomicilio). Ocasionalmente, foram instalas armadilhas de Shannon e feitas inspecoes de paredes e aspiracao em domicilio, peridomicilio e extradomicilio. O tratamento dos dados baseou-se na estimativa das frequencias e abundância das especies, segundo cinco regioes de distintas paisagens originais. Coletaram-se 38.662 flebotomineos de 23 especies. Predominaram Nyssomyia neivai (Pinto) (75.6%), Ny. whitmani (Antunes & Coutinho) (10.1%), Migonemyia migonei (Franca) (7.8%), Expapillata firmatoi (Barreto et al.) (2.1%) and Pintomyia fischeri (Pinto) (1,6%); representando juntas 97,2% dos flebotomineos coletados. Lutzomyia longipalpis (Lutz & Neiva) o principal vetor da LVA nao foi encontrado. No entanto, capturou-se Lu. gaminarai (Cordero et al.), cujas femeas sao morfologicamente semelhantes as de Lu. longipalpis. As especies mais frequentes e abundantes tem sido apontadas como vetores da leishmaniose tegumentar no Parana e em outras areas das Regioes Sudeste e Sul do Brasil. A presenca de Lu. gaminarai no Parana suscita a necessidade de estudos do seu comportamento, inclusive em relacao a sua competencia vetorial do agente da leishmaniose visceral.
53 citations
TL;DR: The silicon fertilization did not affect the preference of the aphids; however it reduced fecundity and the rate of population growth of the insects.
Abstract: The aphid Myzus persicae (Sulzer) is an important pest of potato and causes direct harm, due to the quantity of sap extracted and for being vector of important phytovirus. This work was carried out to evaluate the action of silicon as a resistance inducer of potato to M. persicae. Four treatments were tried: foliar fertilization with silicon acid at 1%; soil fertilization with 250 ml silicic acid solution at 1%; foliar fertilization with silicon acid at 1% + soil fertilization with 250 ml silicic acid solution at 1%; and a control. The treatments were applied thirty days after the explants emergence. Fifteen days after the application of the treatments, feeding preference and some biological aspects of the aphids were evaluated. After, the content of tannins and lignin present in the leaves and the activity of the enzymes peroxidase and phenylalanine ammonia-lyase were also determined. The silicon fertilization did not affect the preference of the aphids; however it reduced fecundity and the rate of population growth of the insects. The lignin percentage increased in the leaves of plants fertilized with silicon via soil and/or foliar and the percentage of tannins increased only in the leaves fertilized via soil plus foliar. The silicon acted as a resistance inducer to M. persicae in potato.
52 citations
TL;DR: The suggestion that trichomes are capable of deterring a non specialist herbivore (H. pachinus) is supported, and it is suggested that a blend of behavioral as well as physical resistance mechanisms is involved.
Abstract: Trichomes reduce herbivore attack on plants by physically and/or chemically inhibiting movement or other activities. Despite evidence that herbivores are negatively affected by trichomes there also reports of insect counter-adaptations that circumvent the plants defense. This paper reports on a study that investigated the likely mechanisms employed by larvae of the nymphalid butterfly, Heliconius charithonia (L.), that allow it to feed on a host that is presumably protected by hooked trichomes (Passiflora lobata (Killip) Hutch). Evidence were gathered using data from direct observations of larval movement and behavior, faeces analysis, scanning electron microscopy of plant surface and experimental analysis of larval movement on plants with and without trichomes (manually removed). The latter involved a comparison with a non specialist congener, Heliconius pachinus Salvin. Observations showed that H. charithonia larvae are capable of freeing themselves from entrapment on trichome tips by physical force. Moreover, wandering larvae lay silk mats on the trichomes and remove their tips by biting. In fact, trichome tips were found in the faeces. Experimental removal of trichomes aided in the movement of the non specialist but had no noticeable effect on the specialist larvae. These results support the suggestion that trichomes are capable of deterring a non specialist herbivore (H. pachinus). The precise mechanisms that allow the success of H. charithonia are not known, but I suggest that a blend of behavioral as well as physical resistance mechanisms is involved. Future studies should ascertain whether larval integument provides physical resistance to trichomes.
48 citations
TL;DR: This study supports the use of a kick-net with a mesh size of 500 microm for macroinvertebrate sampling in RBPs using family level in streams of similar characteristics in Brazil.
Abstract: This study is part of the effort to test and to establish Rapid Bioassessment Protocols (RBP) using benthic macroinvertebrates as indicators of the water quality of wadeable streams in south-east Brazil. We compared the cost-effectiveness of sampling devices frequently used in RBPs, Surber and Kick-net samplers, and of three mesh sizes (125, 250 and 500 µm). A total of 126,815 benthic macroinvertebrates were collected, representing 57 families. Samples collected with Kick method had significantly higher richness and BMWP scores in relation to Surber, but no significant increase in the effort, measured by the necessary time to process samples. No significant differences were found between samplers considering the cost/effectiveness ratio. Considering mesh sizes, significantly higher abundance and time for processing samples were necessary for finer meshes, but no significant difference were found considering taxa richness or BMWP scores. As a consequence, the 500 µm mesh had better cost/effectiveness ratios. Therefore, we support the use of a kick-net with a mesh size of 500 µm for macroinvertebrate sampling in RBPs using family level in streams of similar characteristics in Brazil.
TL;DR: The effects of different application technologies were evaluated on the concentration, viability, and efficiency of infective juveniles of the nematodes Heterorhabditis indica Poinar, Karunakar & David and Steinernema sp.
Abstract: The effects of different application technologies were evaluated on the concentration, viability, and efficiency of infective juveniles of the nematodes Heterorhabditis indica Poinar, Karunakar & David and Steinernema sp. (IBCB-n6) to control Spodoptera frugiperda Smith on corn plants. Two hundred and eighty infective juveniles of Steinernema sp. were required to kill 100% third-instar fall armyworms in petri dishes, as compared to 400 infective juveniles of the H. indica nematode to obtain 75% fall armyworm control. It is possible to spray entomopathogenic nematodes without significant loss in their concentration and viability, with equipment that produces electrical charges to the spraying mix, and with those using hydraulic and rotary nozzle tips. The concentrations of infective juveniles of H. indica and Steinernema sp. nematodes were reduced by 28% and 53%, respectively, when hydraulic spraying nozzles that require 100-mesh filtrating elements were used. Tensoactive agents of the organosilicone and ethoxylate groups did not affect the viability of infective juveniles of Steinernema sp. juveniles. Spraying corn plants (V6 growth stage) with up to 288 million infective juveniles of Steinernema sp. per hectare, diluted in the spraying mix up to 800 L ha-1, with 0.01% ethoxylate tensoactive agent, or at the same volume followed by artificial rain (6 mm water depth) was not sufficient to control S. frugiperda in a controlled environment.
TL;DR: A survey of the bee fauna of Araucaria Forest was performed in the border of a fragment in the district of Porto União, in Santa Catarina State, showing evidences of a seasonal pattern of activity of the bees and the importance of the use of complementary methods to survey the fauna.
Abstract: A survey of the bee fauna of Araucaria Forest was performed in the border of a fragment in the district of Porto Uniao, in Santa Catarina State. Samples were carried on monthly between October/2005 and October/2006 with hand nets directly on the flowers, besides three types of traps: chemical baits, trap nests and pantraps. A total of 1711 bees were captured belonging to 164 species, distributed in five families of bees that occur in Brazil. From the total 1339 bees of 130 species were sampled with the hand net, 346 individuals of 72 species were collected in pantraps, 24 bees of nine species were caught in the trap nests and two specimens of one species were sampled with baits. At most 48 species were common to two or more sample methods. Dialictus, with 27 species, was the most representative genus in the area. The exotic Apis mellifera L. was the most abundant species, representing 49.6% of the sampled bees, following by Dialictus sp.11 with 3.2%. The results show evidences of a seasonal pattern of activity of the bees and the importance of the use of complementary methods to survey the fauna. The composition of the bee fauna was similar to many inventories performed in the Araucaria Forest, being Halictidae the most diverse family followed by Apidae.
TL;DR: As the caterpillars developed in the field, their spatial distribution became increasingly random, as shown by a model adjusted to a straight line, indicating a lack of spatial dependence among samples and geostatistics shows promise for the application of precise methods in the integrated control of pests.
Abstract: The fall armyworm, Spodoptera frugiperda (J.E. Smith), is one of the chief pests of maize in the Americas. The study of its spatial distribution is fundamental for designing correct control strategies, improving sampling methods, determining actual and potential crop losses, and adopting precise agricultural techniques. In Sao Paulo state, Brazil, a maize field was sampled at weekly intervals, from germination through harvest, for caterpillar densities, using quadrates. In each of 200 quadrates, 10 plants were sampled per week. Harvest weights were obtained in the field for each quadrate, and ear diameters and lengths were also sampled (15 ears per quadrate) and used to estimate potential productivity of the quadrate. Geostatistical analyses of caterpillar densities showed greatest ranges for small caterpillars when semivariograms were adjusted for a spherical model that showed greatest fit. As the caterpillars developed in the field, their spatial distribution became increasingly random, as shown by a model adjusted to a straight line, indicating a lack of spatial dependence among samples. Harvest weight and ear length followed the spherical model, indicating the existence of spatial variability of the production parameters in the maize field. Geostatistics shows promise for the application of precise methods in the integrated control of pests.
TL;DR: The results facilitate the decision-making for the management of thrips on cucumber and aggregate the benefits of the correct decision for the adoption of strategies for population reduction.
Abstract: This work determines the best technique, sampling unit and the number of samples to compose a sampling plan for Frankliniella schultzei (Trybom) and Thrips palmi (Karny) (Thysanoptera: Thripidae) on cucumber. The efficacy of three sampling techniques: leaf beating on a plastic tray, direct counting of insects on the lower leaf surface, and whole leaf collection in bags were compared in nine commercial cucumber crops using three sampling units (a leaf from a branch located in the apical, median or basal third of the canopy). The number of samples was determined based on the relative variance and the economic precision for the best technique and sampling unit. The direct counting of insects on the apical third of the plant canopy was the best sampling technique for F. schultzei based on one leaf surveyed per plant using 38 plants per field. The best sampling technique for T. palmi was the leaf beating on a tray using one leaf of the apical third per plant and 35 plants per field. When joining both species, the best sampling system was the direct counting on the apical third, and it requires sampling one leaf per plant using at least 35 plants per field. These results facilitate the decision-making for the management of thrips on cucumber and aggregate the benefits of the correct decision for the adoption of strategies for population reduction.
TL;DR: It is demonstrated that stingless bees can be successfully and efficiently used as pollinators of greenhouse cucumbers during the winter season.
Abstract: When for a successful fruit development the fertilization of flowers is necessary, bees can be used as crop-pollinators in greenhouses. In the present study, we investigated the effectiveness of the stingless bees Scaptotrigona aff. depilis Moure and Nannotrigona testaceicornis Lepeletier as pollinators of cucumber plants (Cucumus sativus var. caipira) in greenhouses during the Brazilian winter season. The study was conducted in four greenhouses (GH), of which two greenhouses contained bee colonies to ascertain pollination of the cucumber plants (GH I, with S. aff. depilis, GH II, with N. testaceicornis), whereas the other two greenhouses (GH III, GH IV) had no bee colonies and served as control groups. Furthermore, we planted cucumbers in an open field plot (OA) where pollination by any/various visiting insects could occur. Each of the experimental areas measured 87.5 m2. Without pollination (GH III, GH IV), the plants produced a low number of cucumbers, and the fruits were smaller and less heavy than in those experimental areas where pollination occurred. In the open field area, not protected against unfavorable climatic conditions, the plants produced fewer flowers than the plants in the greenhouses. The highest cucumber yield (with the highest amount of perfect fruits) was found in those greenhouses which housed the stingless bees as pollinators (GH I, GH II). Our results demonstrate that stingless bees can be successfully and efficiently used as pollinators of greenhouse cucumbers during the winter season.
TL;DR: Evaluating the quality of sugarcane juice from plants attacked by spittlebugs found that chemical treatment was efficient in reducing spittlebug population, and elevated both stalk yield and juice pH, and the concentration of phenolic compounds increased with pest infestation.
Abstract: Mahanarva fimbriolata (Stal) is an important pest in Latin America and causes significant reduction in sugarcane productivity. There is no information regarding the effect of this pest on the quality of cane juice used for sugar and alcohol production. This work aimed at evaluating the quality of sugarcane juice from plants attacked by spittlebugs. The experiment was arranged in a completely randomized design with 15 replications, and comprised two treatments: control and chemical treatment with thiamethoxam. An average of 9.2 +/- 4.44 spittlebug nymphs m-1 were found in the plots prior to insecticide application. Nymphs were counted 18, 35, 55, and 82 days after the initial sampling (december/2003). During the mid growing season (July 2004), the juice was extracted from stalks and analyzed for Brix, Pol, RS, pH, fiber, purity, TRS, dextran, starch, and total phenolic compounds. Stalk yield was also measured. Chemical treatment was efficient in reducing spittlebug population, and elevated both stalk yield and juice pH. The accumulated infestation expressed as insect-days was significantly and negatively correlated to yield, Pol, pH, and purity. The concentration of phenolic compounds increased with pest infestation, while dextran and starch levels were not affected. The infestation of 2.4 and 7.3 nymphs m-1 day-1 caused reductions of 8.3% and 29.8% in yield; 1.9% and 5.8% in Pol; 0.4% and 1.1% in pH and 0.4% and 1.2% in purity, respectively, in comparison to areas where the pest population was extremely low (< 0.1 nymphs m-1).
TL;DR: The external ant community of Hospital Municipal de MorrinHos, in Morrinhos, Goias State, was characterized by the low rates of richness, diversity, dominance and equity of species abundance, and Pheidole sp.1, a polygynic species was numerically dominant in this environment, although it coexists with potentially competitive species.
Abstract: The external ant community of Hospital Municipal de Morrinhos, in Morrinhos, Goias State, was characterized by the low rates of richness, diversity, dominance and equity of species abundance. Pheidole sp.1, a polygynic species was numerically dominant in this environment, although it coexists with potentially competitive species. This ant species prevailed within all hospital departments and its space-time distribution was a little aggregated (variance/mean ratio = 1.102, chi2 = 29.38, P < 0.01). Escherichia, Salmonella, Aeromonas, Enterococcus, Staphylococcus and Klebsiella were the bacteria associated to this ant species in nearly all hospital annexes. The unicolonialism of Pheidole sp.1 tends to increase the contamination and dissemination process of infecto-contagious agents. The control and management of this ant species must be followed by practices that reduce the colonization process by other queens and the quantity of site nidification within the hospital.
TL;DR: In this article, the authors used sardine baits, subterranean traps and direct sampling at four habitats with different soil use (secundary forest, Acacia forestry, initial stage of succession and mixed crops) to investigate the effect of soil use on ant communities.
Abstract: Studies on ant communities in agroecosystems have contributed to the knowledge of the effect of agricultural activities on biological communities. The aim of this study is to explain the effect of soil use on ant communities. We tested the hypothesis that there was a decrease in ant species richness and a change in the species composition at habitats with more intense soil use. We collected ants using sardine baits, subterranean traps and direct sampling at four habitats with different soil use (secundary forest, Acacia forestry, initial stage of succession and mixed crops). The ant species richness did not decrease with intensity of soil use. In successional habitat the species numbers collected using sardine baits and subterranean traps were significantly different. Species composition of communities had a pronounced variation, with the epigaeic and hypogaeic ant faunas of the habitat with high intense soil use (mixed crops) had low similarity with ant communities of the three other habitats. The predator species were restricted to habitats with low intensity of soil use. Then, species composition could better reflect the functional changes on ant communities than species richness. Our data can help to choose the component of ant community that better reflect the response of biodiversity to agricultural impacts.
TL;DR: The influence of temperature on the mating frequency of two lepidopterans, Anticarsia gemmatalis Hubner and Spodoptera frugiperda, which use different strategies of allocation, and with the utilization of nutrients for their reproductive activities is studied.
Abstract: Este trabalho estudou a influencia da temperatura na frequencia de copula de Anticarsia gemmatalis Hubner e Spodoptera frugiperda J. E. Smith, que empregam diferentes estrategias de alocacao, e a utilizacao de nutrientes para suas atividades reprodutivas. Os insetos foram criados em dieta artificial a 25oC, sendo a influencia da temperatura na frequencia de copula, fecundidade, fertilidade e longevidade de adultos avaliada em cinco temperaturas (15, 20, 25, 30 e 35oC). A temperatura afetou a frequencia de copula de ambas as especies, sendo o seu efeito mais evidente nas temperaturas extremas estudadas (15oC e 35oC), principalmente, para A. gemmatalis, que apresentou reducao drastica em sua atividade de copula. Temperaturas intermediarias (20oC a 30oC) permitiram o maior numero de copulas, com S. frugiperda apresentando (ate oito copulas) atividade de copula muito superior a de A. gemmatalis (ate duas copulas). Mesmo com a variacao encontrada na atividade de copula nas diferentes temperaturas, nao foi verificada correlacao entre o numero de copulas e os demais parâmetros biologicos observados (fecundidade, fertilidade e longevidade), com excecao da fecundidade de S. frugiperda a 25oC, que apresentou correlacao positiva com a atividade de copula nessa temperatura (r = 0,589; P = 0,003), indicando que as alteracoes na atividade reprodutiva desse inseto foram decorrentes, basicamente, de sua resposta a temperatura. Femeas de S. frugiperda foram mais fecundas nas temperaturas entre 20oC e 30oC e as de A. gemmatalis a 25oC. A longevidade de ambos os sexos decresceu com o aumento da temperatura para as duas especies estudadas.
TL;DR: In Brazil, just a few cases are known on economic crops, being all restricted to greenhouse crops, and field studies are needed for determining interactions of T. vaporariorum with plants and natural enemies, injury levels, and methods of control.
Abstract: Trialeurodes vaporariorum (West.) is a pest of greenhouse vegetables and ornamentals and infests crops in Europe and in the American continent. In Brazil, just a few cases are known on economic crops, being all restricted to greenhouse crops. In 2003, in Itatiba and neighboring localities of State of Sao Paulo, Brazil, field infestations of T. vaporariorum were observed, mainly on tomato and green bean. So far, whitefly infestation in this area expanded to squash and kale also. Field studies are needed for determining interactions of T. vaporariorum with plants and natural enemies, injury levels, and methods of control.
TL;DR: It is evidenced for the first time that adult females need to feed on coffee in order to produce viable eggs before and during oviposition period and the presence of air bubbles inside the anterior midgut may be due to starvation rather than the response of the environment during flying.
Abstract: The alimentary canal and the reproductive tract of males and females of Hypothenemus hampei Ferrari are described. The alimentary canal of H. hampei showed the crop with several spine-like structures and the midgut with few gastric caeca. We evidenced for the first time that adult females need to feed on coffee in order to produce viable eggs before and during oviposition period. The presence of air bubbles inside the anterior midgut may be due to starvation rather than the response of the environment during flying as previously reported. Two ovaries and the same structures and arrangements common to individuals of the Curculionidae beetles composed the female reproductive system. The male reproductive tract showed a significant difference with respect to other Curculionidae and even other Scolytinae species as it showed a sclerotized aedeagus with several pore-like structures in the terminal portion where sperm is released during mating.
TL;DR: Data suggest the movement of predatory mites from the native areas to the monoculture, which can possibly supply alternative food and habitat for natural enemies of phytophagous mites in the period of food scarceness in the rubber tree crop.
Abstract: The aim of this study was to verify whether fragments of cerrado influence the composition of the mite fauna on rubber trees Five transects distant 50 m, being the first in the edge near the native areas and the last 200 m inside the crop, were established in each rubber tree crop in southern State of Mato Grosso In each transect five plants were chosen, and seven leaves were collected from each plant During one year, 25 quantitative samplings were conducted in two rubber tree crops The lowest number of phytophagous mites occurred in the transect closer to the native vegetation, and the highest number, in the most distant from the native vegetation The largest diversity was also observed in the transect closer to the neighboring vegetation Ten species of predatory mites were also registered in neighboring native areas These data suggest the movement of predatory mites from the native areas to the monoculture These natural areas can possibly supply alternative food and habitat for natural enemies of phytophagous mites in the period of food scarceness in the rubber tree crop The presence of native areas close to culture areas should be taken into account in the elaboration of programs of ecological management of pests
TL;DR: Os resultados comprovam that e possivel estimar a populacao de A. guerreronis nos frutos de coco infestados com a utilizacao da escala diagramatica.
Abstract: Aceria guerreronis Keifer e importante praga do coqueiro no mundo. Dada a falta de metodos padronizados para a quantificacao dos danos causados por esse eriofiideo, uma escala diagramatica com niveis de 1, 2, 4, 8, 16, 32, 48 e 70% de danos foi elaborada e testada para precisao e reprodutibilidade das estimativas. Para validar a escala, frutos com diferentes niveis de dano foram previamente avaliados com o programa Assess® e submetidos a avaliacao por 10 avaliadores inexperientes com e sem a escala (1a avaliacao) e sete dias apos (2a avaliacao) com os mesmos avaliadores, empregando-se as fotos digitalizadas dos mesmos frutos com sequencia diferente. A acuracia e a precisao de cada avaliador foram determinadas por regressao linear simples entre o dano observado e estimado. Sem a utilizacao da escala, sete de 10 avaliadores superestimaram o nivel de dano, sendo pouco precisos. No entanto, avaliadores utilizando a escala obtiveram melhores niveis de acuracia e precisao. Os avaliadores apresentaram niveis mais elevados de reprodutibilidade das estimativas com a utilizacao da escala comparada as avaliacoes sem a escala. A escala foi utilizada para determinar a relacao entre a infestacao e o dano causado por A. guerreronis. A relacao entre infestacao e niveis de dano apresentou elevada precisao (R2 = 99,87%, P < 0,0001) pela equacao lny = 4,948 - 0,121 x + 1,789 lnx. Portanto, os resultados comprovam que e possivel estimar a populacao de A. guerreronis nos frutos de coco infestados com a utilizacao da escala diagramatica.
TL;DR: It is concluded that the regularities in the geographic distribution of body proportions of D. pratensis and D. vittatus do not follow Allen's rule in the sense of thermoregulation, and result from variables that determine growing season length and the allometric growth of different body parts.
Abstract: We studied the geographic variation of three morphometric characters in relation to body size in two South American grasshoppers (Acrididae), Dichroplus vittatus Bruner and D. pratensis Bruner to test Allen's rule in these ectotherms. Since both species follow the converse to Bergmann's rule owing to latitudinal and/or altitudinal variation in time available for growth and reproduction, geographic variation in body size proportions of protruding parts may obey to differential allometric growth in different geographic areas. Alternatively, it could reflect true Allenian variation related to thermoregulation. Body proportions were studied by correlation/regression analyses with geographic and climatic variables. In D. pratensis, body proportions increased with latitude and decreased with altitude. These results probably obey to the effects of water balance and seasonality on final body size, and on the allometric growth of the three studied characters not being related to thermoregulation. In D. vittatus, a generally non-significant trend towards the decrease of the mean proportions of all three characters with increasing latitude was observed. Nevertheless, also in this species, it is probable that the environmental gradient responds to seasonality factors (although not to water balance) that affect the length of growing season and, in consequence, body size and its allometric relationships. We conclude that the regularities in the geographic distribution of body proportions of D. pratensis and D. vittatus do not follow Allen's rule in the sense of thermoregulation, and result from variables that determine growing season length and the allometric growth of different body parts.
TL;DR: Fruit fly populations in Sao Joao da Barra and Cambuci were more similar between each other, composing a distinct group from the populations in Campos dos Goytacazes and Itaocara, and these two groups differed quite a lot from the population in Sao Francisco do Itabapoana.
Abstract: This study aimed to characterize the fruit fly populations in three municipalities of the Northern region and two municipalities of the Northwestern region of Rio de Janeiro State, Brazil, and to evaluate the similarity among their populations. A faunistic analysis was performed from the fruit fly specimens captured in plastic McPhail traps with an aqueous solution of hydrolyzed protein to 5% placed in orchards of guava (Psidium guajava L.) and/or other fruits during 26 months. The total of 3,952 females of 15 species of Anastrepha Schiner and 277 females of Ceratitis capitata (Wied.) was captured. The species richness differed among the municipalities, with the highest value in Sao Francisco do Itabapoana (S = 14), resulting on the highest Shannon-Wiener index (H = 1.27). The equitability was low in the five municipalities due to the dominance of one unique fruit fly species. The predominant species (more frequent, constant and dominant) were Anastrepha obliqua (Macquart) in Campos dos Goytacazes and Sao Francisco do Itabapoana, Anastrepha fraterculus (Wied.) in Cambuci and Itaocara, and Anastrepha sororcula Zucchi in Sao Joao da Barra. Fruit fly populations had low diversity index of Margalef (a = 0.58 to 1.82). Regarding to fruit fly species composition, the populations in Sao Joao da Barra and Cambuci were more similar between each other, composing a distinct group from the populations in Campos dos Goytacazes and Itaocara. These two groups differed quite a lot from the population in Sao Francisco do Itabapoana.
TL;DR: The biology of the pentatomid Dichelops melacanthus (Dallas) feeding on cultivated and non-cultivated plants was studied in the laboratory and survivorship decreased with time on most foods, with approximately 50% of adults alive at day 30.
Abstract: The biology of the pentatomid Dichelops melacanthus (Dallas) feeding on cultivated and non-cultivated plants was studied in the laboratory. Nymph mortality varied from approximately 60 on corn (seed mature) to 77% on wheat (ear immature); no nymphs survived on seedlings of corn or wheat. Nymph developmental time on soybean, corn or wheat (seed, pod or ear) varied from 25.5 to 32.8 days. Body weight at adult emergence was similar and greater on most foods than on wheat ear. Nymphs fed preferentially on soybean (pod immature). On non-cultivated hosts, nymphs showed high mortality (73%) on crotalaria (pod immature); on tropical spiderwort (stem) all nymphs died. Nymphs took longer time to develop on crotalaria and/or on spiderwort than on soybean. Body weight at adult emergence did not differ on crotalaria or soybean. Survivorship decreased with time on most foods, with approximately 50% of adults alive at day 30. On corn and wheat seedlings approximately 80% of adults were dead on day 20. Adult longevity ranged 31-43 days, except on corn and wheat seedlings < 15 days. Females % ovipositing peaked ( approximately 76%) on soybean (pod or seed immature), and was minimum ( approximately 9%) on wheat ear (immature); no females reproduced on seedlings of corn or wheat. Preoviposition period was shorter ( approximately 12 days) on soybean (immature pod or seed) and longer ( approximately 37 days) on wheat (ear immature). Fecundity was similar and higher on all foods than on wheat (ear immature). Body weigh gain occurred on all foods, but on corn and wheat seedlings. Adults fed preferably on soybean (pod immature and seed mature); wheat (seedling) was the least preferred food.
TL;DR: This paper describes the unique behavior of one dung beetle species, Canthon aff.
Abstract: Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) compete intensively for dung resources, and most species forage in the understory. Here, we describe the unique behavior of one dung beetle species, Canthon aff. quadriguttatus (Olivier), associated with two species of monkeys from Peru. We observed this beetle species on the genital and anal regions of the brown titi monkey, Callicebus brunneus (Wagner), and subsequently falling with dung as the monkeys defecated. The same association was also observed with the bald-faced saki monkey, Pithecia irrorata irrorata (Gray). Using the " sit and wait" at the source behavior, C. quadriguttus may arrive first at the dung resource, possibly out-competing other dung beetle species. This paper is the first report of this behavior for C. aff. quadriguttatus on the brown titi monkey and bald-faced saki monkey from southeastern, Amazonian Peru. We discuss this behavior in the context of competition and resource partitioning, and also speculate as to why C. aff. quadriguttatus has been found on both monkey species.
TL;DR: In this article, the morphological variation of Agelaia pallipes (Olivier) in five sites along an altitudinal gradient (2600-3380 m) in the Santuario de Iguaque, Colombia, were studied in order to test whether or not the species follows Jame's rule, and whether body parts follow a homogeneous variation.
Abstract: Jame's rule proposes a direct relationship between body size and altitude. There are several studies about this rule; however, few studies analyze proportional changes in body parts along gradients. The morphological variation of Agelaia pallipes (Olivier) in five sites along an altitudinal gradient (2600-3380 m) in the Santuario de Iguaque, Colombia, were studied in order to test whether or not the species follows Jame's rule, and whether body parts follow a homogeneous variation. Body variation analysis was conducted through multivariate analysis of variance (MANOVA) and the relationship between altitude and each morphometric measurement was studied through regression analyses. The MANOVA indicated significant differences among sites. An increase in altitude leads to a reduction in body size, especially in hind femur length and head width. However, measurements linked to flight such as mesosoma height, mesoscutum width, and fore wing size showed a reverse tendency. Possibly all described changes are consequence of both reduction on food availability and lower atmospheric pressure. The low temperature of high areas may strongly limit foraging and thus food availability. Lower atmospheric pressure reduces flight potential and may result in an increase in size of both wings and flight muscles. This paper underscores the need to study in detail the changes in body proportions in species with wide distribution ranges in latitude and altitude.
TL;DR: The objective of this study was to describe the adult male reproductive system of three Trypoxylon (Trypargilum) species, which have similar reproductive systems, which are formed by a pair of testes, each one with three fusiforme follicles, from which emerges an efferent duct that later joins forming a deferent duct.
Abstract: Variations in the adult male reproductive system among different groups of Hymenoptera offer characteristics that help studies on behavior and phylogenetics. The objective of this study was to describe the adult male reproductive system of three Trypoxylon (Trypargilum) species. For that, tissues were disseced, fixed in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and postfixed in 1% osmium tetroxide. The material was dehydratated and embedded for light and electron transmission microscopes. The species have similar reproductive systems, which are formed by a pair of testes, each one with three fusiforme follicles, from which emerges an efferent duct that later joins forming a deferent duct. The deferent duct opens into an ejaculatory duct. The first half of the deferent duct is enlarged and differentiated in a region specialized in sperm storage, the seminal vesicle. The accessory gland flows in the post-vesicular region of the deferent duct. The testes and vesicles are both covered with a conjunctive capsule. Sexually mature individuals have all spermatogenesis stages in their follicles. Sperms are released from testes in bundles which are disorganized inside seminal vesicles.