309 resultados para parasitoids


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The relative oviposition rate of the parasitoid Fopius arisanus (Sonan) was investigated across three frugivorous tephritid species, Bactrocera tryoni Froggart, Bactrocera jarvisi (Tryon) and Bactrocera cucumis French. Choice and no-choice tests were both used. The suitability of these three species for sustaining larval development and survival to the adult stage was also assessed. Fopius arisanus parasitized all three tephritid species. regardless of the method of exposure, but showed stronger preference for B. tryoni and B. jarvisi over B. cucumis. Superparasitism was extremely rare. Successful development of F. arisanus varied across host species. Bactrocera tryoni yielded significantly more parasitoids than B. jarvisi, but no wasps emerged from B. cucumis puparia. Tests were set up in replicated trials. but results were not homogeneous across trials. We discuss the host relationships of F. arisanus with reference to this variation and in relation to host suitability for larval development.

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The aphelinid parasitoid Coccophagus gurneyi Compere has unusual sex-related host relationships. Females are diploid and develop internally within mealybugs Pseudococcus calceolariae (Maskell). Males, in contrast, are haploid and hyperparasitic, developing on primary parasitoid larvae within the mealybugs. Furthermore, males have been claimed to be capable of either internal or external development, depending on the precise site of deposition of the haploid egg. This diversity of developmental pathways could indicate the existence of a sibling-species complex. We therefore quantified the mating and ovipositional behaviour of C. gurneyi, for comparison with that of an undescribed sibling species. We also checked whether the females deposit male eggs in alternative sites. The pattern of mating was found to be typical of mating behaviour in Coccophagus spp. and was consistent among all mating pairs, suggesting that the colony comprised one species. Further, the mating behaviour was significantly different from that of the undescribed sibling species. The site of male egg deposition varied and is apparently dictated by two factors; whether the mealybug is parasitised and, if so, the size of the parasitoid it contains. If the mealybugs were unparasitised or if the parasitoids within the mealybugs were small (< 0.53 mm), male eggs were deposited within the mealybug haemocoel. If the parasitoids were large (> 1.05 mm), male eggs were deposited within the parasitoids. These results support the claim of alternate host relationships and developmental pathways within males of C. gurneyi.

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Taeniogonalos raymenti is confirmed as a hyperparasitoid of the tachinid Sturmia convergens which parasitises larval Danaus plexippus. Trigonalids are indirect parasitoids and in this case we have direct evidence that wasp eggs must have been laid on the caterpillar's host plant. Asclepias fruticosa. before the secondary host, but not necessarily before the primary tachinid host, was present. Levels of hyperparasitism during our sampling period were very low at less than two percent.

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The relative potential of the pathogenic fungi Beauveria bassiana and Zoophthora radicans for use as autodisseminated biological control agents of the diamondback moth (Plutella xylostella) was compared. The LC50 of B. bassiana conidia to third instar larvae was 499 conidia/mm(2) of leaf surface and individual cadavers of mycosed fourth instar larvae yielded a mean of 67.5 X 10(6) (+/- 7.5 x 10(6)) conidia. All concentrations of B. bassiana tested in inoculation chambers (0.24, 2.4, and 6.2 mug/mm(2)) induced 100% mortality in adult male moths within 7 days. The times to death and sporulation were concentration and exposure duration dependent. A standard procedure for inoculating male moths resulted in > 85% mortality from Z. radicans and > 93% mortality from B. bassiana. Pairing of inoculated males with clean moths of both sexes yielded higher rates of passive transmission of B. bassiana than Z. radicans, but there was no evidence for sexual transmission of either pathogen. Similarly, B. bassiana was more effectively transmitted from inoculated male moths to larvae foraging on whole plants. Single sporulating cadavers producing B. bassiana or Z. radicans conidia placed on plants infested with larvae resulted in a similar rate of transmission for both pathogens. However, an increase of the density of sporulating cadavers from one to three/plant increased Z. radicans transmission (greater than fourfold) but had no effect on B. bassiana transmission. Simultaneous inoculations of larvae with conidia of both fungi reduced the mortality induced by each pathogen, the reduction being most acute for B. bassiana-induced mortality. Inoculation of adults with both fungi showed that, at concentrations required for effective passive transmission to larvae, B. bassiana severely inhibited Z. radicans mycosis in adults. (C) 2001 Academic Press.

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Sistemática, Morfologia e Biogeografia

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Foram estudadas as espécies de Anisepyris Kieffer, 1905, coletadas em 31 localidades ao longo da Mata Atlântica Brasileira. Foram descritas e ilustradas as seguintes espécies novas: A. basilongus Santos sp. nov., A. foveapertus Santos sp. nov., A. artus Santos sp. nov., A. basilargus Santos sp. nov., A. cepus Santos sp. nov. e A. ramosus Santos sp. nov.. Foram examinados espécimes adicionais de dezesseis espécies previamente descritas: A. amazonicus Westwood, 1874, A. bifidus Evans, 1966, A. bipartitus Santos & Azevedo, 2000, A. delicatus Evans, 1966, A. dentatus Santos & Azevedo, 2000, A. divisus Santos, 2002, A. inconspicuus Santos, 2002, A. lobatus Santos & Azevedo, 2000, A. longimerus Santos & Azevedo, 2000, A. nigripes Evans, 1966, A. proteus Evans, 1966, A. rotundus Santos, 2002, A. similis Santos & Azevedo, 2000, A. triangularis Moreira & Azevedo, 2003, A. trinitatis Evans, 1966 e A. tuberosus Santos & Azevedo, 2000, incluindo citações geográficas novas e suas variações taxonômicas, sendo o primeiro registro de A. bipartitus, A. dentatus, A. similis e A. trinitatis para a Mata Atlântica.

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Survey of the hymenopterous parasitoids (Insecta, Hymenoptera) from the Parque Estadual da Fonte Grande, Vitória, ES, Brazil. Parasitoids Hymenoptera were collected in a trail inside the Parque Estadual da Fonte Grande (20º17'51.7''S; 40º20'13.1''W), located in an area of the Atlantic Forest, during the period of June 2000 to July 2001. A total of 4,595 specimens, belonging to 28 families, have been collected. Braconidae, Eulophidae, and Scelionidae, were the most common families, with relative abundance of 22.5%, 14.32%, and 13.12%, respectively. Sixteen families showed the relative frequency lower than 1%. A preliminary list with 47 genera of some of the families is included.

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Adultos de Cephalonomia stephanoderis Betrem foram detectados em novembro de 2003 durante amostragem de frutos de Coffea canephora Pierre ex A. Froehner danificados por Hypothenemus hampei Ferrari (Coleoptera: Scolytidae) em Ouro Preto D'Oeste, RO (10º45'S e 62º15'W). De janeiro a julho de 2004, o parasitóide foi amostrada mensalmente em 200 frutos danificados por H. hampei. Provavelmente, C. stephanoderis exerça alguma pressão de parasitismo sobre a população da broca-do-café. A ocorrência do parasitóide em condições naturais aponta para outra alternativa de controle biológico de H. hampei em Rondônia. Este é o primeiro registro de C. stephanoderis em plantações de café na Amazônia brasileira.

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Sistemática, morfologia e biogeografia

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A broca-pequena-do-fruto, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) é uma praga de grande importância na cultura do tomateiro. Desta forma, métodos de manejo que auxiliem no controle dessa praga e que reduzam a aplicação de agrotóxicos devem ser estudados. O objetivo do presente trabalho foi avaliar métodos alternativos de manejo da broca-pequena-do-fruto, como: o controle biológico, através da utilização de parasitoides do gênero Trichogramma e nematoides entompatogênicos (Heterorhabditis indica e Sterneneima carpocapsae); o controle físico, por meio do ensacamento de cachos de tomate com o tecido-não-tecido (TNT); e o controle químico através do estudo da atividade inseticida de plantas como a pimenta, o fumo, o alho e a mamona nas fases embrionárias, larval, pupal e adulta. Desta forma, por meio das análises foi possível verificar que a espécie e/ou linhagem de Trichogramma que mais se destacou foi T. galloi (Tg1) com características biológicas favoráveis ao manejo de N. elegantalis. Para os nematoides entomopatogênicos, S. carpocapsae, foi o mais efetivo, causando uma mortalidade de 82,93% a uma concentração de 65 juvenis infectivos por pré-pupa da broca-pequena-do-fruto. Através do ensacamento dos frutos, foi possível verificar a redução na oviposição da praga em frutos do tomateiro para quase zero com sacolas de TNT com fundo fechado, não ocorrendo alteração no peso, pH e graus brix do fruto, enquanto que no controle químico através de inseticidas botânicos foi possível verificar o destaque do extrato aquoso de fumo, reduzindo a oviposição, entrada e saída das lagartas nos frutos; causando mortalidade na fase embrionária, lagarta, pré-pupa e pupa da broca-pequena-do-fruto.

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We present the fi rst review of Hymenoptera alien to Europe. Our study revealed that nearly 300 species of Hymenoptera belonging to 30 families have been introduced to Europe. In terms of alien species diversity within invertebrate orders, this result ranks Hymenoptera third following Coleoptera and Hemiptera. Two third of alien Hymenoptera are parasitoids or hyperparasitoids that were mostly introduced for biological control purposes. Only 35 phytophagous species, 47 predator species and 3 species of pollinators have been introduced. Six families of wasps (Aphelinidae, Encyrtidae, Eulophidae, Braconidae, Torymidae, Pteromalidae) represent together with ants (Formicidae) about 80% of the alien Hymenoptera introduced to Europe. Th e three most diverse families are Aphelinidae (60 species representing 32% of the Aphelinid European fauna), Encyrtidae (55) and Formicidae (42) while the Chalcidoidea together represents 2/3 of the total Hymenoptera species introduced to Europe. Th e fi rst two families are associated with mealybugs, a group that also included numerous aliens to Europe. In addition, they are numerous cases of Hymenoptera introduced from one part of Europe to another, especially from continental Europe to British Islands. Th ese introductions mostly concerned phytophagous or gall- maker species (76 %), less frequently parasitoids. Th e number of new records of alien Hymenoptera per year has shown an exponential increase during the last 200 years. Th e number of alien species introduced by year reached a maximum of 5 species per year between 1975 and 2000. North America provided the greatest part of the hymenopteran species alien to Europe (96 species, 35.3%), followed by Asia (84 species, 30.9%) and Africa (49 species, 18%). Th ree Mediterranean countries (only continental parts) hosted the largest number of alien Hymenoptera: Italy (144 spp.), France (111 spp.) and Spain (90 spp.) but no correlation was found with the area of countries. Intentional introduction, mostly for biological control, has been the main pathway of introduction for Hymenoptera. Consequently, the most invaded habitats are agricultural and horticultural as well as greenhouses. To the contrary, Hymenoptera alien in Europe are mostly associated with woodland and forest habitats. Ecological and economic impacts of alien Hymenoptera have been poorly studied. Ants have probably displaced native species and this is also true for introduced parasitoids that are suspected to displace native parasitoids by competition, but reliable examples are still scarce. Th e cost of these impacts has never been estimated.

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The reproductive capacity of females of Apanteles galleriae (Wilkinson, 1932) was evaluated in fifth instar caterpillars of Galleria mellonella (Linnaeus, 1758) and Achroia grisella (Fabricius, 1754) fed on standard diet and diets enriched with protein. The reproductive capacity of parasitoid females on fifth instar caterpillars of G. mellonella and A. grisella with variable weight was also evaluated. The host weight interfered in the sex ratio of the obtained parasitoids. In heavier caterpillars, the investment in female descendants was greater than in males, and in lighter caterpillars the inverse occurred.

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The thermal requirements of Palmistichus elaeisis Delvare & LaSalle, 1993 were determined by rearing this pupal parasitoid in the following lepidopteran hosts: Diatraea saccharalis (Fabricius, 1794) (Crambidae), Anticarsia gemmatalis (Hübner, 1818), Heliothis virescens (Fabricius, 1777), Spodoptera frugiperda (J.E. Smith, 1797) (Noctuidae) and Thyrinteina arnobia (Stoll, 1782) (Geometridae). The experiment was set in laboratory conditions (temperatures between 18ºC and 30ºC, RH=70 ± 10% and 14-hour photoperiod). The life cycle (egg-adult) ranged from 40.4 ± 0.63 days (18ºC, H. virescens) to 18.1 ± 0.13 days (28ºC, D. saccharalis). The thermal constant of the egg-adult period ranged from 353.1 (D. saccharalis) to 407.7 degree-days (S. frugiperda). The lowest thermal threshold ranged from 5.0ºC (A. gemmatalis) to 7.5ºC (D. saccharalis). At 30ºC, all prepupae died. These results suggest that P. elaeisis can be reared in laboratory on all the hosts tested.

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Aleiodes Wesmael is the most diverse rogadine genus, with koinobiont endoparasitic development in Lepidoptera caterpillars resulting in mummification of the host remains. Aleiodes japi sp. nov. is described and illustrated. Type specimens of the new species were reared from Physocleora grosica and Ischnopteris sp. (Lepidoptera, Geometridae, Ennominae) larvae. Host larvae were collected on Alchornea triplinervia (Euphorbiaceae) at the Reserva Biológica Municipal da Serra do Japi, Jundiaí, São Paulo, Brazil. This is the second species of circumscriptus/gastritror group described from Brazil.

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Report for the scientific sojourn at the University of Lund, Sweden, between May and September 2007. A landscape-scale research approach has been highlighted by a growing body of literature as essential for understanding important ecosystem services as biological control. Aphids are victims of a diversity of enemies making the aphid-enemy interaction a nice example for the role of enemy diversity for the functioning of biological control. Here it is examined the effects of landscape complexity on cereal aphids and associated natural enemies that varied in the degree of specialization. Parasitoids wasps abundance did not differ between landscape types but was strongly negatively related to the percentage of arable land. In contrast, abundances of generalist predators like Coccinellidae were significantly higher in simple landscapes since can benefit from the high availability of a variety of alternative resources within cropping systems. Consequently coccinellidae-to-aphid ratio was significantly higher in fields in homogenous landscapes as compared to fields included in an heterogeneous landscape, suggesting that enemy pressure on cereal aphids increases with landscape simplification. The landscape effect will depend mainly on the degree of specialization of functionally dominant natural enemies, so that the results imply that conservation actions aiming to optimise abundance for one taxonomic group in the agricultural landscape will not automatically increase abundance of other groups. Given that the strength of natural enemy impact on biocontrol depends on landscape features and the role of functionally dominant natural enemies. So, therefore it is essential to focus the future empirical work in examining the schedule of agricultural landscapes that maintain a diversity of generalist and specialist natural enemies.