Papers by Cherre Bezerra Da Silva
It is common for a female trichogrammatid to lay more than one egg per host, a phenomenon known a... more It is common for a female trichogrammatid to lay more than one egg per host, a phenomenon known as self-superparasitism, which exposes her offspring to intraspecific, intrinsic competition (IIC) with its own siblings. Information about how often self-superparasitism occurs and how IIC interacts with abiotic factors is rare, especially regarding the Neotropical Trichogramma species. Here we determined the frequency of self-superparasitism in Trichogramma atopovirilia Oatman & Platner (Ta) and T. pretiosum Riley (Tp), and the effects of IIC and temperature on the sex ratio, egg-to-adulthood period, and survivorship of both species' offspring. Individual females were offered eggs of Spodoptera frugiperda (J.E. Smith) for 30 min. A group of para-sitized hosts was then dissected for determination of the self-superparasitism frequency, while another group was incubated at 15, 18, 21, 24, 27, 30, and 33 C. High rates of self-superparasitism were found in both Ta (0.55 6 0.07) and Tp (0.62 6 0.06). IIC interacted with temperature decreasing Ta and Tp's survivorship, lengthening the egg-to-adulthood period in Tp and shortening it in Ta, and balancing Ta's sex ratio. Based on survivorship rate, Ta and Tp could not be differentiated if their immatures develop in absence of IIC. However, in its presence, Tp was 3 Â more likely to survive than Ta at 33 C, while at 15 C Ta survived 2Â better than Tp. These results show that self-superparasitism can be very common in both Ta and Tp, and that its effects on the species' biological traits and competitiveness strongly depend on the IIC–temperature interaction.
The Citrus mealybug Planococcus citri has a wide geographical distribution and has been described... more The Citrus mealybug Planococcus citri has a wide geographical distribution and has been described as a pest of economic importance in several crops. The present work determined the developmental and biological aspects of the Citrus mealybug in order to obtain information that may support the integrated pest management (IPM) of grapevine (Vitis vinifera L.) cv. Syrah in the Lower Basin of the São Francisco Valley region. The research was conducted at the Laboratory of Entomology of Embrapa Semiarid, Petrolina-PE, on leaves of grapevine kept in a controlled environment (25 ± 1°C, 60 ± 10% R. H. and a photoperiod of 12L:12D). The first two instars had higher mortality, indicating high susceptibility in these nymphal periods. The overall nymphal period of females and males is similar at 22.52 ± 0.46 and 23.5 ± 0.29 days, respectively, with viability of 39%. The adult longevity of females is nearly 30 times greater than that of males, indicating that females of P. citri are mainly responsible for damage and injury to grapevine. The sex ratio was 0.64, indicating that females make up the majority of the adult population of P. citri. We conclude that the species in question completes its lifecycle on leaves of grapevine and reaches the adult phase in a short time interval.
Telenomus remus and Trichogramma spp. (Hymenoptera: Platygastridae, Trichogrammatidae) are known ... more Telenomus remus and Trichogramma spp. (Hymenoptera: Platygastridae, Trichogrammatidae) are known egg parasitoids of the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) in Brazil. Reports of trichogrammatids parasitism on eggs of S. frugiperda have been relatively common, whereas the occurrence of T. remus in Brazilian crops has rarely been reported. Consequently, literature that gives insights about the interspecific competition among individuals of T. remus and Trichogramma spp. in field is very scarce. Here we report the simultaneous occurrence of T. remus, Trichogramma pretiosum and Tr. atopovirilia on eggs of the FAW in maize (Piracicaba, São Paulo, Brazil). Our findings imply that these three egg parasitoid species were engaged in exploitative competition (indirect interaction, where the depletion of resources by one species prevents the other access to it) towards eggs of S. frugiperda. Moreover, given the emergence of combinations of two and three of these parasitoid species from a single egg mass, our data strongly suggest that T. remus, Tr. pretiosum and Tr. atopovirilia were also engaged in interference competition (direct interactions among adults and/or immature individuals resulting in behavioral changes or even death of individuals). Both exploitative and interference competitions may affect the population dynamics of parasitoids with consequences to the biological control of pests. Hence, the present findings highlight the importance of determining the outcome of competition among T. remus, Tr. pretiosum and Tr. atopovirilia towards eggs of S. frugiperda in laboratory and field studies.
Biological traits, such as body size, fecundity and fertility, of egg parasitoids are strongly in... more Biological traits, such as body size, fecundity and fertility, of egg parasitoids are strongly influenced by host species, and the use of a single-host species for consecutive generations has been showed to be detrimental for egg parasitoid biology. Besides biological traits, behaviour of egg parasitoids is also an important parameter for implying their performance in the field, but information about the effect of host on the behaviour of egg parasitoids is still scarce. Thus, this work aimed at determining the influence of host species on the short-range flight capacity of three egg parasitoids Trichogrammatoidea annulata De Santis, Trichogramma atopovirilia Oatman and Platner and Trichogramma bruni Nagajara reared on Anagasta kuehniella (Zeller), Corcyra cephalonica (Stainton) and Sitotroga cerealella (Olivier), for first, 10 and 28 consecutive generations. Trichogrammatids emerged inside a tubular dark flight chamber, under controlled conditions, and short-range flying response was based on the proportions of adults trapped to the sticky top of the chamber and the ones found on the bottom, which were checked for defective wings. Our data clearly demonstrate that trichogrammatid short-range flight depends on the fasctidious host species. All three egg parasitoids had their flight capacity significantly reduced when emerged from S. cerealella. The highest flying capacity of T. annulata was registered when reared on C. cephalonica, while for T. atopovirilia was on A. kuehniella and T. bruni on both C. cephalonica and A. kuehniella. Parasitoid flight capacity is affected when reared on the same host over generations; however, it was not possible to define a pattern for any of the trichogrammatids. Our findings are of great relevance for quality control of mass-reared egg parasitoids because measuring only behavioural traits with use of flight chambers can be more practical and less timeconsuming than assessing biological parameters.
The southern house mosquito, Culex quinquefasciatus, has one of the most acute and eclectic olfac... more The southern house mosquito, Culex quinquefasciatus, has one of the most acute and eclectic olfactory systems of all mosquito species hitherto studied. Here, we used Illumina sequencing to identify olfactory genes expressed predominantly in antenna, mosquito's main olfactory organ. Less than 50% of the trimmed reads generated by high-quality libraries aligned to a transcript, but approximately 70% of them aligned to the genome. Differential expression analysis, which was validated by quantitative realtime PCR on a subset of genes, showed that approximately half of the 48 odorant-binding protein genes were enriched in antennae, with the other half being predominantly expressed in legs. Similar patterns were observed with chemosensory proteins, "plus-C" odorant-binding proteins, and sensory neuron membrane proteins. Transcripts for as many as 43 ionotropic receptors were enriched in female antennae, thus making the ionotropic receptor family the largest of antennae-rich olfactory genes, second only to odorant receptor (OR) genes. As many as 177 OR genes have been identified, including 36 unique transcripts. The unique OR genes differed from previously annotated ORs in internal sequences, splice variants, and extended N or C terminus. One of the previously unknown transcripts was validated by cloning and functional expression. When challenged with a large panel of physiologically relevant compounds, CquiOR95b responded in a dose-dependent manner to ethyl 2-phenylacteate, which was demonstrated to repel Culex mosquitoes, and secondarily to citronellal, a known insect repellent. This transcriptome study led to identification of key molecular components and a repellent for the southern house mosquito.
Age of host eggs can be a limiting factor for egg parasitoids. It is expected that old eggs are l... more Age of host eggs can be a limiting factor for egg parasitoids. It is expected that old eggs are less preferred by egg parasi- toids, which can discriminate between eggs of different ages by using chemical cues. The objective of this study was to determine the preference, development and arrestment of Telenomus remus Nixon (Hymenoptera: Scelionidae) parasitizing Spodoptera frugi- perda (J.E. Smith) (Lepidoptera: Noctuidae) eggs of different ages. This egg parasitoid preferred to parasitize 1- and 2-day-old eggs rather than 3-day-old eggs in choice and no-choice assays. However, although the percentage emergence of parasitoids is signifi- cantly lower from 2- and 3-day-old eggs the sex ratio and developmental time are unaffected. Parasitoids spent longer searching sub- strates impregnated with extracts of 1- and 2-day old eggs than 3-day-old eggs. Our results reveal that T. remus is able to distinguish the most suitable (1-day-old) from the least suitable (3-day-old) host eggs, but unable to recognize the unsuitability of intermediate aged eggs. Egg arrestants may be responsible for the preference of T. remus for ovipositing in 1- and 2-day old eggs.
In order to identify and evaluate the occurrence of arthropods-pest and predators on mangoes at “... more In order to identify and evaluate the occurrence of arthropods-pest and predators on mangoes at “Vale do São Francisco”, northestern Brazil, studies were carried out in eight commercial plantations of the cv. Tommy Atkins, from February 2000 to January 2002. In each area, fruit flies were collected using McPhail and Jackson traps; other pests and predators were evaluated on samples of branches, panicles and fruits. The arthropods-pest occurrence in decreasing order were: Aceria mangiferae (Sayed) (Acari: Eriophyidae) - 87.0%; Pseudaonidia tribitiformis (Green) (Hemiptera: Diaspididae) - 70.1%; Ceratitis capitata Wied. (Diptera: Tephritidae) - 66.1%; Erosomyia mangiferae Felt (Diptera: Cecidomyiidae) - 64.6%; Pleuroprucha asthenaria Walker (Lepidoptera: Geometridae) - 42.9%; Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) - 39.3%; Anastrepha spp. (Diptera: Tephritidae) - 33.0%; Selenothrips rubrocinctus (Giard) (Thysanoptera: Thripidae) - 26.4%; Oligonychus sp. (Acari: Tetranychidae) - 16.6%; Frankliniella schultzei (Trybom) (Thysanoptera: Thripidae) - 13.1%; unidentified mirid - 9.1%, and aphids [Aphis craccivora Koch; Toxoptera aurantii (Boyer de Fonscolombe), A. gossypii Glover (Hemiptera: Aphididae)] - 7.2%. The predators were: Euseius concordis (Chant) and E. citrifolius (Denmark & Muma) (Acari: Phytoseiidae) - 32.7%; Cheletogenes ornatus (Canestrini & Fanzago) (Acari: Cheyletidae) - 32.3%; Rubroscirus sp. (Acari: Cunaxidae) - 17.7%; unidentified arachnids - 16.6%, and Chrysoperla externa (Hagen) and Ceraeochrysa cubana (Hagen) (Neuroptera: Chrysopidae) - 3.7%.
Bragantia, 2009
The attractiveness of Tagetes patula L. (marigold) to thrips (Thysanoptera) in greenhoused melon ... more The attractiveness of Tagetes patula L. (marigold) to thrips (Thysanoptera) in greenhoused melon was evaluated. Abundance, dominance, frequency, and constancy of thrips species were studied by using faunistic analysis, cluster analysis (CA) and principal component analysis (PCA). Marigold was planted only at the edge of the greenhouses. Insect sampling on melon plants was taken by shaking three vine growing ends on a white tray whereas similar procedure was used for sampling marigold but shaking all plants of 1 m2. Samplings points where on T. patula edge, on melon planted along with marigold, and on melon planted at 6m, 12m, 18m, and 24m from marigold edge. Eleven thrips species were found on both melon and marigold plants: Neohydatothrips sp., Frankliniella sp. 1, Frankliniella sp. 2, Frankliniella schultzei (Trybom), Scirtothrips sp., Caliothrips sp., Microcephalothrips sp., Franklinothrips vespiformis (Crawford), Arorathrips sp., Ceratothripoides sp., and Haplothrips sp. The dominant species were: Neohydatothrips sp., Frankliniella sp. 1, F. schultzei, and Caliothrips sp. Analyses of the dominant species indicate three different groups according to abundance: (1) marigold, (2) melon along with T. patula, and (3) melon at 6m, 12m, 18m, and 24m from marigold. Significant differences among sampling sites were verified by using CA and PCA. Therefore, T. patula is attractive to thrips and may be used as trap crop in melon cultivation for several thrips species.
Avaliou-se a eficiência de dois inseticidas granulados, terbufós e carbofuran em diferentes dosag... more Avaliou-se a eficiência de dois inseticidas granulados, terbufós e carbofuran em diferentes dosagens, no controle da broca da bananeira Cosmopolites sordidus. Também avaliou-se o efeito dos equipamentos de aplicação Swissmex (S) e Matraca (M) na eficiência do terbufós. O experimento foi instalado em plantio comercial, no município de Petrolina-PE (Brasil), em blocos ao acaso com seis tratamentos e cinco repetições. Os tratamentos (g ingrediente ativo/cova – equipamento aplicação) foram: 1. terbufós 150 G (1,95) S; 2. terbufós 150 G (3,00) S; 3. terbufós 50 G (3,00) S; 4. terbufós 50 G (3,00) M; 5. carbofuran 50 G (4 g) M e 6. testemunha (não-tratada). Nos tratamentos 1, 2 e 3 o inseticida foi aplicado com o equipamento Swissmex (S) e nos tratamentos 4 e 5 com Matraca (M). Foram utilizadas 30 plantas da cv. Pacovan por tratamento, sendo avaliado o número de insetos antes da aplicação. Mensurou-se o efeito dos tratamentos sobre a praga aos 90 e 120 dias após a aplicação, com base nas galerias decorrentes da infestação da broca. Os dados foram estatisticamente analisados e as médias comparadas pelo teste de Tukey a 5%. Dados do coeficiente de infestação dos rizomas foram
transformados em raiz (x + 0,5) . Calculou-se a eficiência média dos tratamentos pela fórmula de Abbott. Os produtos terbufós e carbofuran, nas dosagens testadas, mostraram-se eficientes no controle da broca da bananeira, contudo não se constatou diferença significativa entre os tratamentos químicos, nem entre os equipamentos de aplicação. As percentagens de eficiência dos produtos testados variaram de 96,7 a 100%.
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Papers by Cherre Bezerra Da Silva
transformados em raiz (x + 0,5) . Calculou-se a eficiência média dos tratamentos pela fórmula de Abbott. Os produtos terbufós e carbofuran, nas dosagens testadas, mostraram-se eficientes no controle da broca da bananeira, contudo não se constatou diferença significativa entre os tratamentos químicos, nem entre os equipamentos de aplicação. As percentagens de eficiência dos produtos testados variaram de 96,7 a 100%.
transformados em raiz (x + 0,5) . Calculou-se a eficiência média dos tratamentos pela fórmula de Abbott. Os produtos terbufós e carbofuran, nas dosagens testadas, mostraram-se eficientes no controle da broca da bananeira, contudo não se constatou diferença significativa entre os tratamentos químicos, nem entre os equipamentos de aplicação. As percentagens de eficiência dos produtos testados variaram de 96,7 a 100%.