Bianca Ambrogi - Academia.edu (original) (raw)

Papers by Bianca Ambrogi

Journal of Insect Behavior, Mar 1, 2016

Changes in the signaling effort of virgin females are known to occur until their first mating. Yo... more Changes in the signaling effort of virgin females are known to occur until their first mating. Young females tend to increase the calling effort (number and time duration of bouts) as they age. In this context, the calling behavior of virgin females of Atheloca subrufella, an important pest of coconut palms (Cocos nucifera), was studied under laboratory conditions. Thirty four virgin females were observed during 16 scotophases (25 ± 2 °C, 75 ± 5 % RH and 10 h scotophase), until they stopped calling in the following photophase. The calling position, pattern and frequency were evaluated. Females of A. subrufella showed only one calling position, and calling peaked between the second and fifth scotophases. Most females did not start calling immediately after emergence. Neither the individual duration of calling nor the number of calling bouts changed over time. However, the time that calling started was earlier in older females, probably to avoid competition with younger females and increase the probability of mating. These data support the hypothesis that there is an age-dependent pattern of pheromone emission in virgin females of A. subrufella.

Arthropod-plant Interactions, May 17, 2021

Indirect plant defense is an important component in regulating population dynamics and the struct... more Indirect plant defense is an important component in regulating population dynamics and the structure of numerous communities in different ecosystems. These defenses mainly involve the emission of volatile organic compounds (VOCs) induced after damage by an herbivore. VOCs can play several ecological roles, such as help natural enemies locate prey or hosts, attract or repel other herbivores, mediate communication between neighboring plants and among different parts of the same plant, and affect the behavior of pollinators and seed dispersers. In addition to VOCs, some plants produce extrafloral nectar, which can enhance plant defense, by attracting, retaining, and increasing the efficiency of some natural enemies; however, among the associated costs, these compounds can attract other herbivorous species and exclude some natural enemies due to competition. Many factors can influence the production of indirect defenses by plants, such as the individual species, life stage, density of herbivores, age, abiotic factors, as well as the association of plants with symbiotic microorganisms. The potential of indirect plant defenses to reduce herbivory and increase the plant fitness has been well demonstrated. Indirect plant defenses may have ecological costs but can express phenotypic plasticity, as plants can reduce or increase the production of defenses according to the associated herbivory rate. Such variable expression of characteristics provides a barrier against the evolution of resistance by the associated herbivores. In this article, we intend to provide a review on volatile organic compounds and extrafloral nectar as indirect plant defenses, including some costs and benefits of these defense mechanisms.

Austral entomology, Mar 22, 2016

Experimental and Applied Acarology, Feb 24, 2018

Upon damage by herbivores, plants induce an array of volatile organic compounds (VOCs) that media... more Upon damage by herbivores, plants induce an array of volatile organic compounds (VOCs) that mediate ecological interactions involving communication with organisms of the second and third trophic levels. VOC-mediated tritrophic interactions have largely been studied in various systems, including cassava (Manihot esculenta), but little is known about the chemical nature of herbivore-induced VOCs in this crop and the response they evoke in natural enemies. Several tetranychid and predatory mites are associated with cassava. Here, VOC emissions from uninfested plants and plants infested with 200 or 400 Mononychellus tanajoa, a specialist herbivore on cassava, and the generalists Tetranychus urticae and T. gloveri were measured. Dual-choice experiments were also conducted to assess the preference of inexperienced (reared on prey-infested bean plants) and experienced (adapted on prey-infested cassava plants) predatory mites, Neoseiulus idaeus (Phytoseiidae), between odors of uninfested plants versus odors of plants infested with M. tanajoa, T. urticae or T. gloveri. Two hundred individuals significantly increased the emissions of (Z)-3-hexen-1-ol, (E)-β-ocimene, β-caryophyllene, alloaromadendrene and (E)-geranyl acetone in T. urticae-infested plants, and (E)-β-ocimene and methyl salicylate (MeSA) in T. gloveri-infested plants. Four hundred individuals significantly increased the emissions of (Z)-3-hexen-1-ol, MeSA, α-pinene and D-limonene in M. tanajoa-infested plants. In addition, T. urticae at this density induced (E)-β-ocimene, D-limonene, (E)geranyl acetone and six compounds that were not detected in other treatments. Tetranychus gloveri-infested plants induced the emissions of (E)-2-hexenal and D-limonene. Regardless of the infesting species, inexperienced N. idaeus did not discriminate between uninfested or infested plants. Upon experience, they discriminated between the odors of uninfested and T. urticae-damaged plants. Our findings reveal that mite infestations in cassava result * Bianca G.

Journal of Chemical Ecology, Mar 1, 2012

Journal of Applied Entomology, Feb 1, 2008

Phytochemistry, Oct 1, 2016

Cassava (Manihot esculenta Crantz) is one of the most important staple crops worldwide. It consti... more Cassava (Manihot esculenta Crantz) is one of the most important staple crops worldwide. It constitutes the major source of carbohydrates for millions of low-income people living in rural areas, as well as a cash crop for smallholders in tropical and sub-tropical regions. The Food and Agriculture Organization of the United Nations predicts that cassava plantations will increase and production systems will intensify in the future, highlighting the need for developing strategies that improve the sustainability of production. Plant chemical defenses hold the potential for developing pest management strategies, as these plant traits can influence the behavior and performance of both pests and beneficial arthropods. Cassava plants are well-defended and produce a number of compounds involved in direct defense, such as cyanogenic glycosides, flavonoid glycosides, and hydroxycoumarins. In addition, volatile organic compounds induced upon herbivory and the secretion of extrafloral nectar act as indirect defense against herbivores by recruiting natural enemies. Here, cassava chemical defenses against pest arthropods are reviewed, with the aim of identifying gaps in our knowledge and areas of research that deserve further investigation for developing sound pest control strategies to improve sustainable production of this crop, and how these defenses can be used to benefit other crops. Cyanogenic content in cassava is also highly toxic to humans, and can cause irreversible health problems even at sub-lethal doses when consumed over prolonged periods. Therefore, the promotion of chemical defense in this crop should not aggravate these problems, and must be accompanied with the education on processing methods that reduce human exposure to cyanide.

BioAssay, Jul 3, 2009

Eficácia da Confusão Sexual de Machos no Controle do Bicho-mineiro do Café Leucoptera coffeella (... more Eficácia da Confusão Sexual de Machos no Controle do Bicho-mineiro do Café Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae) RESUMO-O bicho-mineiro do café Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae) é considerado atualmente a principal praga desta cultura no Brasil. O controle por meio de inseticidas tem sido o mais utilizado, causando problemas para o homem e o meio ambiente. Para amenizar estes problemas, têm-se desenvolvido novas técnicas de manejo de pragas. A técnica denominada confusão sexual de machos objetiva interferir na comunicação entre os parceiros sexuais. A viabilidade desta técnica foi avaliada em uma lavoura de café onde foram instaladas três unidades experimentais de 20 ha, sendo uma área tratada com feromônio sexual sintético, outra com aplicações de inseticidas e por fim uma área controle. Como agente de confusão sexual de machos foi utilizada a mistura racêmica de 5,9-dimetilpentadecano, na concentração de 1 g do feromônio por liberador. Para liberação do feromônio no campo foram utilizados 20 liberadores por hectare. A eficiência desta técnica foi avaliada por meio da comparação de machos capturados em armadilhas tipo delta (20 armadilhas por unidade experimental) contendo 0,5 mg de 5,9-dimetilpentadecano, em septos de borracha, entre as unidades experimentais. O número de folhas minadas também foi avaliado. A análise dos resultados permite concluir que a presença do feromônio não diminuiu o número de machos capturados, bem como não reduziu o número de folhas minadas. Diversos fatores podem ter contribuído para o insucesso na interrupção do acasalamento dessa espécie, como diferenças na composição química, dosagem ou na formulação empregada do feromônio dos liberadores, o momento de aplicação na lavoura, densidade populacional da praga no início do experimento e fatores climáticos. PALAVRAS-CHAVE-feromônio sexual, manejo integrado de pragas, comunicação química ABSTRACT-The coffee leaf miner, Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae), is the main pest of coffee plantations in Brazil. Indiscriminate chemical control has been used frequently to control the attack of L. coffeella, causing serious problems to the environment. To avoid such problems, new techniques have been developed to control the attack of this pest. A technique to control lepidopteran pests, called mating disruption, aims to obstruct the communication among sexual partners. The potential of pheromone-mediated mating disruption for control of leaf miner population was evaluated in a coffee plantation in Patrocínio-MG, Brazil. Three experimental areas were installed: 20 ha plot treated with synthetic sex pheromone; another 20 ha plot with insecticide applications and 20 ha plot maintained as control. The pheromone plot was treated with 400 pheromone dispensers with 1g of 5,9-dimethylpentadecane per dispenser. The efficacy of mating disruption was evaluated by the comparison of number of males caught in delta traps (20 traps per plot) baited with 0.5 mg of 5,9dimethylpentadecane. The number of mined leaves was also recorded in each plot. The presence of pheromone did not reduce the number of males caught nor decreased the number of mined leaves in the plot. The failure of the mating disruption technique may be attributed to a combination of several factors, such as composition and dose of the pheromone and its formulation, the moment of application in the crop, the population density at the begin of the experiment and climatic factors. KEY WORDS-sex pheromone, integrated pest management, chemical communication The coffee leaf miner Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae) is the main pest of coffee in Brazil, due to continuous presence in the crop and the economic damage to the Mating Disruption for Control of Leucoptera coffeella Ambrogi et al.

Entomologia Experimentalis Et Applicata, Feb 12, 2022

Leaf‐cutting ants (LCA) try to reduce the risk of contamination in their colonies by avoiding con... more Leaf‐cutting ants (LCA) try to reduce the risk of contamination in their colonies by avoiding contact with their nest refuse (NR), as it can harbor substances harmful to them and their symbiotic fungi. Here, we tested whether an aqueous extract with 10% (vol/vol) of NR of the leaf‐cutting ant Atta opaciceps Borgmeier (Hymenoptera: Formicidae, Attini) causes a deterrent effect. We placed leaves of Hibiscus rosa‐sinensis L. (Malvaceae) sprayed with NR extract or distilled water (control) in the foraging areas of 12 colonies – eight colonies of A. opaciceps and four of Atta sexdens (L.) – for 60 min, on three consecutive days. The fresh weight of remaining leaf fragments between treatments was compared using linear‐mixed effect models. Leaf consumption was significantly lower in the presence of NR extract for 48 h, indicating that the NR odor impregnated in the leaves may have been the responsible factor for the deterrence. Further studies are needed to establish a deterrent extract with a broad spectrum and lasting effect on plants, and to better understand the mechanisms involved in deterrence.

EntomoBrasilis, Apr 13, 2014

Resumo. Espécies de Diptera, principalmente as moscas, tem se mostrado como potenciais bioindicad... more Resumo. Espécies de Diptera, principalmente as moscas, tem se mostrado como potenciais bioindicadores para mudanças ambientais. Para captura destes animais, há diferentes métodos, incluindo as armadilhas com atrativos alimentares. Neste estudo, para avaliar a eficiência de armadilhas na captura de moscas usando isca de melaço de cana-de-açúcar, foram avaliados os parâmetros ecológicos: abundância, riqueza e composição de espécies de moscas, comparando diferentes períodos de exposição das armadilhas em campo: 24, 48, 72 e 96h. A riqueza e abundância apresentaram mudança significativa em relação ao tempo de exposição da isca, tendo se estabilizado após 48h, e a composição diferiu entre o primeiro dia (24h) e os demais (48, 72, 96h).

Applied Soil Ecology, Oct 1, 2012

Espécies de Diptera, principalmente as moscas, tem se mostrado como potenciais bioindicadores par... more Espécies de Diptera, principalmente as moscas, tem se mostrado como potenciais bioindicadores para mudanças ambientais. Para captura destes animais, há diferentes métodos, incluindo as armadilhas com atrativos alimentares. Neste estudo, para avaliar a eficiência de armadilhas na captura de moscas usando isca de melaço de cana-de-açúcar, foram avaliados os parâmetros ecológicos: abundância, riqueza e composição de espécies de moscas, comparando diferentes períodos de exposição das armadilhas em campo: 24, 48, 72 e 96h. A riqueza e abundância apresentaram mudança significativa em relação ao tempo de exposição da isca, tendo se estabilizado após 48h, e a composição diferiu entre o primeiro dia (24h) e os demais (48, 72, 96h)._________________________________________________________________________________________ ABSTRACT: Diptera species, especially flies, has shown potential as bioindicators for environmental changes. There are different methods to capture these animals, including tr...

The coconut moth Atheloca subrufella Hulst (Lepidoptera: Pyralidae) is considered an important pe... more The coconut moth Atheloca subrufella Hulst (Lepidoptera: Pyralidae) is considered an important pest of coconut crops in Brazil, which is the fourth largest global coconut producer. Concerning the economic importance of this crop and aiming to increase the knowledge related to biological control, the present research aimed records the first occurrence of Venturia sp. (Hymenoptera: Ichneumonidae) parasitizing A. subrufella caterpillars in the State of Sergipe, Brazil. Coconuts infested by A. subrufella caterpillars were collected in coconut plantation and kept in the Entomology Laboratory (Universidade Federal de Sergipe – UFS) until the emergence of A. subrufella adults or the parasitoids. The parasitoids obtained were identified as Venturia sp.._________________________________________________________________________________________ RESUMO: A traça-do-coqueiro Atheloca subrufella Hulst (Lepidoptera: Pyralidae) é considerada uma importante praga da cultura do coqueiro no Brasil, o qu...

Journal of Chemical Ecology, 2007

The sex pheromone of Lonomia obliqua Walker (Lepidoptera: Saturniidae) was studied in the laborat... more The sex pheromone of Lonomia obliqua Walker (Lepidoptera: Saturniidae) was studied in the laboratory. All female calling occurred during the scotophase. Most females (70.6%) called first within 24 hr of eclosion. Calling varied with age of female, with older (5-to 6-day-old) females calling earlier in the scotophase and for longer durations than younger (0-to 1-day-old) females. The sex pheromone gland of 1-to 3-day-old virgin females was extracted during the calling peak. A Y-olfactometer bioassay showed significant attraction of males to a filter paper containing the female gland extract. Gas chromatographic-electroantennogram detection (GC-EAD) analysis of the extract indicated the presence of at least two possible pheromone components. Gas chromatographic-mass spectrometric analysis of the major GC-EAD-active peak indicated a hexadecenyl acetate; chemical derivatization indicated Δ11 unsaturation. Synthetic samples of (E)-and (Z)-11hexadecenyl acetate were obtained by coupling 10-bromo-1-decanol and 1-hexyne, utilizing lithium chemistry. The comparison of the retention time of dimethyl disulfide derivatives of the natural compound, to those of synthetic chemicals, confirmed the natural compound as (E)-11-hexadecenyl acetate. The minor component was identified as the related alcohol, (E)-11-hexadecenol. The ratio of the two components in female extract was 100:35. Preliminary tests of males in a Y-olfactometer showed that their response to a mixture of the two compounds was not significantly different from that to gland extract.

Cadernos de Agroecologia, Sep 14, 2020

Plantas cultivadas de forma orgânica podem influenciar o comportamento de herbívoros? Can organic... more Plantas cultivadas de forma orgânica podem influenciar o comportamento de herbívoros? Can organic plants influence the behavior of herbivores?

BioAssay, 2009

Entomologia Experimentalis et Applicata

Analyses of the headspace volatiles produced by males and females of Sternechus subsignatus Bohem... more Analyses of the headspace volatiles produced by males and females of Sternechus subsignatus Boheman (Coleoptera: Curculionidae) revealed seven male-specific compounds. The major component was (E)-2-(3,3-dimethylcyclohexylidene)-ethanol, and the minor components were 1-(2′-hydroxyethyl)-1-methyl-2-isopropenylcyclobutane (grandisol), 7-methyl-3-methyleneoct-6-en-1-ol, (Z)-2-(3,3-dimethylcyclohexylidene)-ethanol, (Z)-and (E)-2-(3,3-dimethylcyclohexylidene)-acetaldehyde, and (E)-2-(3,3-dimethylcyclohexylidene) acetic acid. The latter compound is described for the first time as a natural product. Only four of the seven identified compounds showed electrophysiological activity. Enantioselective gas chromatography showed that the natural grandisol is the (1R,2S)-stereoisomer. The major component, (E)-2-(3,3-dimethylcyclohexylidene)-ethanol, attracted S. subsignatus in olfactometer bioassays. Studies are in progress to evaluate the biological activity of the major component and the EAD-acti...

Sociobiology, 2005

Trail fidelity in leaf-cutting ants could be an adaptive strategy for the optimization of the for... more Trail fidelity in leaf-cutting ants could be an adaptive strategy for the optimization of the foraging activity of a colony. The aim of the present study was to verify the existence of trail fidelity in Acromyrmex niger F. Smith (1858) and the possible factors associated with this behavior. Two hypotheses were tested: (i) Spatial complexity of the colony - the larger and more complex the colony the higher the proportion of ants restricted to a particular foraging site; (ii) Influence of the type of collected resource - ants from different colony nest entrances collect resources of different qualities. Three adult colonies with different sizes (two, three and five nest entrances) were used in this study. Previously marked workers entering with food were collected in two nest entrances of each colony. In addition, a qualitative evaluation was made of the type of resource collected at the nest entrances. More than 80% of the collected workers used the nest entrance where they were prev...