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Sample records for lysiphlebus hirticornis mackauer

  1. Veranderingen in de lijst van Nederlandse snuitkevers: Simo hirticornis vervalt voor onze fauna en S. variegates wordt toegevoegd (Coleoptera: Curculionidae)

    NARCIS (Netherlands)

    Heijerman, T.

    2002-01-01

    Changes to the Dutch list of weevils: Simo hirticornis to be deleted and S. variegatus to be added (Coleoptera: Curculionidae). Some years ago Palm (1995) discovered that the weevil ‘Simo hirticornis’ was a mixture of two species: S. hirticornis en S. variegatus. Dutch material from institutional co

  2. [Quality of different aphids as hosts of the parasitoid Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae)].

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    Silva, Robson J; Bueno, Vanda H P; Sampaio, Marcus V

    2008-01-01

    Lysiphlebus testaceipes (Cresson) has a broad aphid host range; however the quality of these preys may interfere in its biological feature. This study aimed to evaluate the quality of three Macrosiphini, Brevicoryne brassicae (L.), Lipaphis erysimi (Kaltenbach) and Myzus persicae (Sulzer), and three Aphidini Schizaphis graminum (Rondani) Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover as hosts to L. testaceipes and to determine the relation possible of host preference, of size and quality of the host. The tests were carried out in climatic chamber at 25 +/- 1 degrees C, RH 70 +/- 10% and 12h photophase. The parasitoid did not oviposite in B. brassicae and L. erysimi, while the other species were nutritionally suitable to the parasitoid. L. testaceipes showed preference for aphids from tribe Aphidini and these hosts presented better quality to the parasitoid when compared to Macrosiphini. Interactions among size, preference and quality between the Aphidini were found. L testaceipes showed preference (parasitism rate 76.7%) for R. maidis, the bigger host (hind tibia with 0.281 mm). This host provided bigger size (hind tibia with 0.49 mm) and higher emergence rate (95.6%) to the parasitoid when compared to A. gossypii (parasitism rate of 55.7%). Also the smaller host A. gossypii (0.266 mm) provided smaller size hind tibia (0.45 mm) and higher mortality of the parasitoid (emergence rate 72.1%). However, the development time was shorter and the longevity was higher in A. gossypii (6.3 and 5.4 days, respectively) when compared to the host R. maidis (6.7 and 3.8 days, respectively), and not been related to host size.

  3. Occurrence of Lysiphlebus testaceipes parasitizing Aphis gossypii in watermelon in the State of Rio Grande do Norte, Brazil Ocorrência de Lysiphlebus testaceipes parasitando Aphis gossypii em melancia, no Estado do Rio Grande do Norte, Brasil

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    Luciano Pacelli Medeiros Macedo

    2010-09-01

    Full Text Available This is the first report of the parasitoid Lysiphlebus testaceipes (Cresson as a biological control agent of the aphid Aphis gossypii Glover in watermelon crop in Vale do Açu, RN. It was observed that near the harvest, almost all collected aphids were mummified, and after analyzing the emerged parasitoids, the parasitoid L. testaceipes was identified. Therefore, in the future, this species may be included in A. gossypii integrated management programs.Este é o primeiro relato do parasitoide Lysiphlebus testaceipes (Cresson como agente de controle biológico do pulgão Aphis gossypii Glover na cultura da melancia, na região do Vale do Açu, Rio Grande do Norte (RN. Observou-se que próximo da colheita quase todos os pulgões coletados encontravam-se mumificados e, na análise dos parasitoides emergidos, constatou-se o parasitismo por L. testaceipes. Essa espécie, portanto, poderá ser incluída em um programa de manejo integrado de A. gossypii futuramente.

  4. Tritrophic associations and taxonomic notes on Lysiphlebus fabarum (Marshall (Hymenoptera: Braconidae: Aphidiinae, a keystone aphid parasitoid in Iran

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    Rakhshani Ehsan

    2013-01-01

    Full Text Available An investigation of host associations, distribution and types of reproduction (sexual, asexual of Lysiphlebus fabarum (Marshall across 20 provinces of Iran during 2006-2011 was undertaken. The parasitoid was reared from three groups of host aphids belonging to genera Aphis and Brachycaudus, and occasional host aphid genera. Aphis craccivora Koch was the most frequent host aphid for L. fabarum on various host plants, including economically important crops. The field sex ratio generally favored females, but in some cases, only thelytokous (uniparental populations were found. In those cases, the host was always an Aphis species. Specimens reared from Brachycaudus aphids were all biparental, indicating the presence of a sibling biological species. Overall analysis of diagnostic morphological characters in the forewing indicated intra-specific variability in forewing marginal setae as well as variations in length of the R1 vein. [Projekat Ministarstva nauke Republike Srbije, br. 43001

  5. Quality of different aphids as hosts of the parasitoid Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae); Qualidade de diferentes especies de pulgoes como hospedeiros do parasitoide Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae, Aphidiinae)

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    Silva, Robson J.; Bueno, Vanda H.P. [Universidade Federal de Lavras, MG (Brazil). Dept. de Entomologia]. E-mail: vhpbueno@ufla.br; Sampaio, Marcus V.[Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Ciencias Agrarias]. E-mail: mvsampaio@iciag.ufu.br

    2008-03-15

    Lysiphlebus testaceipes (Cresson) has a broad aphid host range; however the quality of these preys may interfere in its biological feature. This study aimed to evaluate the quality of three Macrosiphini, Brevicoryne brassicae (L.), Lipaphis erysimi (Kaltenbach) and Myzus persicae (Sulzer), and three Aphidini Schizaphis graminum (Rondani) Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover as hosts to L. testaceipes and to determine the relation possible of host preference, of size and quality of the host. The tests were carried out in climatic chamber at 25 {+-} 1 deg C, RH 70 {+-} 10% and 12h photophase. The parasitoid did not oviposite in B. brassicae and L. erysimi, while the other species were nutritionally suitable to the parasitoid. L. testaceipes showed preference for aphids from tribe Aphidini and these hosts presented better quality to the parasitoid when compared to Macrosiphini. Interactions among size, preference and quality between the Aphidini were found. L. testaceipes showed preference (parasitism rate 76.7%) for R. maidis, the bigger host (hind tibia with 0.281 mm). This host provided bigger size (hind tibia with 0.49 mm) and higher emergence rate (95.6%) to the parasitoid when compared to A. gossypii (parasitism rate of 55.7%). Also the smaller host A. gossypii (0.266 mm) provided smaller size hind tibia (0.45 mm) and higher mortality of the parasitoid (emergence rate 72.1%). However, the development time was shorter and the longevity was higher in A. gossypii (6.3 and 5.4 days, respectively) when compared to the host R. maidis (6.7 and 3.8 days, respectively), and not been related to host size. (author)

  6. Fertility life table of Lysiphlebus testaceipes (Cresson) (Hymenoptera, Braconidae, Aphidiinae) in Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover (Hemiptera, Aphididae); Tabela de vida de fertilidade de Lysiphlebus testaceipes (Cresson) (Hymenoptera, Braconidae, Aphidiinae) em Rhopalosiphum maidis (Fitch) e Aphis gossypii Glover (Hemiptera, Aphididae)

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    Silva, Robson Jose da; Bueno, Vanda Helena Paes; Silva, Diego Bastos [Universidade Federal de Lavras (UFLA), MG (Brazil). Dept. de Entomologia. Lab. de Controle Biologico], e-mail: ecosbio@yahoo.com.br, e-mail: vhpbueno@ufla.br; Sampaio, Marcus Vinicius [Universidade Federal de Uberlandia, Umuarama, MG (Brazil). Inst. de Ciencias Agrarias], e-mail: mvsampaio@iciag.ufu.br

    2008-07-01

    Fertility life table of Lysiphlebus testaceipes (Cresson) (Hymenoptera, Braconidae, Aphidiinae) in Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover (Hemiptera, Aphididae). The evaluation of the growth potential of Lysiphlebus testaceipes (Cresson) is important for its use in biological control programs of aphids. This work aimed to evaluate the fertility life table of L. testaceipes in Rhopalosiphum maidis (Fitch) and Aphis gossypii Glover. To determine the immature mortality, development and the sex ratio of the parasitoid, 12 females parasitoid, and 480 nymphs of each aphids were used. To evaluate the longevity and fertility 15 female parasitoid were used. Nymphs of each aphid (3 day old) were offered for each parasitoid female daily, until the female died, being 300 (first day); 250 (second day); 200 (third day); 150 (fourth day) and 50 nymphs in the other days. L. testaceipes showed immature mortality rates of 5.6 % in R. maidis and 9.2 % in A. gossypii. The development time of L. testaceipes in R. maidis and A. gossypii was 10.2 and 10.1 days, and the sex ratio of 0.71 and 0.66, respectively. The female of L. testaceipes had a fecundity of 498.8 eggs in R. maidis and 327.8 eggs in A. gossypii. The growth parameters the L. testaceipes in R. maidis and A. gossypii were, respectively R{sub o}= 205.38 and 164.08 females; r{sub m}= 0.449 and 0.431 females/females/day; {lambda}= 1.57 and 1.54 females/day; T= 11.86 and 11.83 days and TD= 10.78 and 11.27 days. L. testaceipes showed great growth potential on both aphid hosts. R. maidis could be a suitable host for proposals of mass-rearing and open rearing system using L. testaceipes. (author)

  7. Singing on the wings! Male wing fanning performances affect female willingness to copulate in the aphid parasitoid Lysiphlebus testaceipes (Hymenoptera: Braconidae: Aphidiinae).

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    Benelli, Giovanni; Kavallieratos, Nickolas G; Donati, Elisa; Giunti, Giulia; Stefanini, Cesare; Canale, Angelo

    2016-08-01

    Lysiphlebus testaceipes (Hymenoptera: Braconidae: Aphidiinae) is a generalist endoparasitoid attacking more than 100 aphid species. In L. testaceipes, wing fanning is a main male courtship display evoked by a female-borne sex pheromone. However, no information is available on the characteristics and behavioral role of male fanning during courtship in this parasitoid. Here, the courtship behavior of a wild strain of L. testaceipes was quantified and the male wing fanning performances were analyzed through high-speed video recordings and examined in relation to mating success. Courtship sequence of wild L. testaceipes did not substantially differ from that previously reported for other populations mass reared on aphids. We observed that the male courtship duration did not affect mating success. However, video analysis revealed that the males producing high-frequency fanning signals achieved higher mating success over those that display low-frequency fanning. Wing fanning before successful and unsuccessful courtship differed in amplitude of wing movements and alignment toward the mate, highlighting that frontal courtship positively influence the female mating decisions. This study increases knowledge on sexual behavior in a key parasitoid of aphids, highlighting the importance of wing fanning among the range of sensory modalities used in the sexual communication of L. testaceipes. From a practical point of view, this information is useful in L. testaceipes-based biocontrol strategies, since it can help to establish parameters for quality checking of mass-reared wasps over time.

  8. Coevolutionary fine-tuning: evidence for genetic tracking between a specialist wasp parasitoid and its aphid host in a dual metapopulation interaction.

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    Nyabuga, F N; Loxdale, H D; Heckel, D G; Weisser, W W

    2012-04-01

    In the interaction between two ecologically-associated species, the population structure of one species may affect the population structure of the other. Here, we examine the population structures of the aphid Metopeurum fuscoviride, a specialist on tansy Tanacetum vulgare, and its specialist primary hymenopterous parasitoid Lysiphlebus hirticornis, both of which are characterized by multivoltine life histories and a classic metapopulation structure. Samples of the aphid host and the parasitoid were collected from eight sites in and around Jena, Germany, where both insect species co-occur, and then were genotyped using suites of polymorphic microsatellite markers. The host aphid was greatly differentiated in terms of its spatial population genetic patterning, while the parasitoid was, in comparison, only moderately differentiated. There was a positive Mantel test correlation between pairwise shared allele distance (DAS) of the host and parasitoid, i.e. if host subpopulation samples were more similar between two particular sites, so were the parasitoid subpopulation samples. We argue that while the differences in the levels of genetic differentiation are due to the differences in the biology of the species, the correlations between host and parasitoid are indicative of dependence of the parasitoid population structure on that of its aphid host. The parasitoid is genetically tracking behind the aphid host, as can be expected in a classic metapopulation structure where host persistence depends on a delay between host and parasitoid colonization of the patch. The results may also have relevance to the Red Queen hypothesis, whereupon in the 'arms race' between parasitoid and its host, the latter 'attempts' to evolve away from the former.

  9. Dicty_cDB: Contig-U16491-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available -FP_184309 Lysiphlebus testaceipes adult whol... 42 2e-06 4 ( EE005677 ) ROE00013406 Rhizopus oryzae Company... Rhizopus oryz... 44 5e-06 3 ( EE008408 ) ROE00006012 Rhizopus oryzae Company Rhizopus oryz... 44 7e-06 3 ( ...0275 ) ROE00001450 Rhizopus oryzae Company Rhizopus oryz... 44 1e-05 3 ( FE418452 ) CBTW3224.fwd CBTW_Daphni... clone:DCBAZD05, 5'end, expresse... 48 7e-04 2 ( EE002886 ) ROE00002950 Rhizopus oryzae Company

  10. Dicty_cDB: Contig-U11246-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 6_C04_F08ZS Wheat developing grains cDNA li... 34 0.001 4 ( CJ633337 ) Triticum a...A clone:whe25c08, 5' end, si... 34 0.004 4 ( BQ838716 ) WHE3591_H04_O07ZS Wheat developing grains cDNA li...... 4 ( DQ002738 ) Aegilops tauschii clone 8-H11 alpha-gliadin stora... 36 0.004 4 ( BQ806479 ) WHE3579_E10_I19ZS Wheat developing grain...HE3592_B10_C20ZS Wheat developing grains cDNA li... 34 0.005 4 ( EH013428 ) USDA-FP_186229 Lysiphlebus testa...WHE3586_C09_F18ZS Wheat developing grains cDNA li... 34 0.005 4 ( CA717420 ) wdk4

  11. Distribution, parasitoids and cyclic appearance of Russian wheat aphid Diuraphis noxia (Mordvilko, 1913 (Hemiptera, Aphididae in Algeria

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    Malik Laamari

    2016-12-01

    Full Text Available This information on the Russian wheat aphid Diuraphis noxia (Hemiptera, Sternorrhyncha, Aphididae in those regions of Algeria where cereals are grown is based on a nineteen year study. This revealed that this aphid is widely distributed in the high plateaus and interior plains with semi-arid climates. The mummies of this aphid found among its colonies were collected and 4 parasitoids (Hymenoptera, Braconidae, Aphidiinae where identified. These were Diaeretiella rapae (M’Intosh, Aphidius matricariae (Haliday, Aphidius rhopalosiphi (Destefani and Lysiphlebus testaceipes (Cresson, with D. rapae the most abundant. Moreover, this study also indicates that the cyclical appearance of this aphid is determined by the intensity of precipitation during winter and spring.

  12. Occurrence and parasitism of aphids (Hemiptera: Aphididae on cultivars of irrigated oat (Avena spp. in São Carlos, Brazil

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    Júlio Cesar Ronquim

    2004-06-01

    Full Text Available The interactions between aphids and their Hymenopteran parasitoids on irrigated oats as well as the response of different cultivars of cereals regarding the resistance to these aphids and the influence on the host/parasitoid relationships were studied during two years in São Carlos, Brazil. Rhopalosiphum padi (L. was the predominant aphid observed throughout the study, while the other species were rarely found. Five species of parasitic Hymenoptera were found: three primary parasitoids, Lysiphlebus testaceipes (Cresson, Aphidius colemani (Viereck and Diaeretiella rapae (M'Intosh and two hyperparasitoids, Syrphophagus aphidivorus (Myer and Alloxysta brassicae (Ashmead. The UPF 86081 cultivar presented significant results regarding lower Rhopalosiphum padi contamination and higher aphid parasitism rates than those observed on some other cultivars. No significant effect on the percentage variation of parasitoid emergence on the mummified aphids was observed throughout this study.Foram avaliadas as interações entre afídeos e seus himenópteros parasitóides em cultivares de aveia irrigada, como também a resposta de diferentes cultivares em relação resistência à estes afídeos e a influência nas relações hospedeiro/parasitóide durante dois anos em São Carlos, SP, Brasil. Rhopalosiphum padi (L. foi o afídeo predominante ao longo do estudo, enquanto as outras espécies raramente foram encontradas. Foram observadas cinco espécies de himenópteros parasitóides: três parasitóides primários, Lysiphlebus testaceipes (Cresson, Aphidius colemani (Viereck e Diaeretiella rapae (M'Intosh e dois hiperparasitóides, Syrphophagus aphidivorus (Myer and Alloxysta brassicae (Ashmead. A cultivar UPF 86081 apresentou resultados significativos quanto à baixa infestação por Rhopalosiphum padi e maiores taxas de parasitismo que a demais cultivares. Não foi observado efeito significativo na variação de porcentagem de emergência de parasit

  13. Aphid honeydew quality as a food source for parasitoids is maintained in Bt cotton.

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    Hagenbucher, Steffen; Wäckers, Felix L; Romeis, Jörg

    2014-01-01

    Bt-transgenic cotton has proven to be highly efficient in controlling key lepidopteran pests. One concern with the deployment of Bt cotton varieties is the potential proliferation of non-target pests. We previously showed that Bt cotton contained lower concentrations of insecticidal terpenoids as a result of reduced caterpillar damage, which benefited the aphid Aphis gossypii. It is thus important that non-target herbivores are under biological control in Bt cotton fields. The induction or lack of induction of terpenoids could also influence the quality of aphid honeydew, an important food source for beneficial insects. We therefore screened A. gossypii honeydew for cotton terpenoids, that are induced by caterpillars but not the aphids. We then tested the influence of induced insect-resistance of cotton on honeydew nutritional quality for the aphid parasitoid Lysiphlebus testaceipes and the whitefly parasitoid Eretmocerus eremicus. We detected the cotton terpenoids gossypol and hemigossypolone in A. gossypii honeydew. Although a feeding assay demonstrated that gossypol reduced the longevity of both parasitoid species in a non-linear, dose-dependent manner, the honeydew was capable of sustaining parasitoid longevity and reproduction. The level of caterpillar damage to Bt and non-Bt cotton had no impact on the quality of honeydew for the parasitoids.These results indicate that the nutritional quality of honeydew is maintained in Bt cotton and is not influenced by induced insect resistance.

  14. Aphid honeydew quality as a food source for parasitoids is maintained in Bt cotton.

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    Steffen Hagenbucher

    Full Text Available Bt-transgenic cotton has proven to be highly efficient in controlling key lepidopteran pests. One concern with the deployment of Bt cotton varieties is the potential proliferation of non-target pests. We previously showed that Bt cotton contained lower concentrations of insecticidal terpenoids as a result of reduced caterpillar damage, which benefited the aphid Aphis gossypii. It is thus important that non-target herbivores are under biological control in Bt cotton fields. The induction or lack of induction of terpenoids could also influence the quality of aphid honeydew, an important food source for beneficial insects. We therefore screened A. gossypii honeydew for cotton terpenoids, that are induced by caterpillars but not the aphids. We then tested the influence of induced insect-resistance of cotton on honeydew nutritional quality for the aphid parasitoid Lysiphlebus testaceipes and the whitefly parasitoid Eretmocerus eremicus. We detected the cotton terpenoids gossypol and hemigossypolone in A. gossypii honeydew. Although a feeding assay demonstrated that gossypol reduced the longevity of both parasitoid species in a non-linear, dose-dependent manner, the honeydew was capable of sustaining parasitoid longevity and reproduction. The level of caterpillar damage to Bt and non-Bt cotton had no impact on the quality of honeydew for the parasitoids.These results indicate that the nutritional quality of honeydew is maintained in Bt cotton and is not influenced by induced insect resistance.

  15. Single-locus recessive inheritance of asexual reproduction in a parasitoid wasp.

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    Sandrock, Christoph; Vorburger, Christoph

    2011-03-08

    The evolutionary maintenance of sex is one of the big unresolved puzzles in biology. All else being equal, all-female asexual populations should enjoy a two-fold reproductive advantage over sexual relatives consisting of male and female individuals. However, the "all else being equal" assumption rarely holds in real organisms because asexuality tends to be confounded with altered genomic constitutions such as hybridization and polyploidization or to be associated with parthenogenesis-inducing microbes. This limits the ability to draw general conclusions from any particular system. Here we describe a new system that permits unbiased comparisons of sexual and asexual reproduction: the parasitic wasp Lysiphlebus fabarum. Crossing experiments demonstrated that asexual reproduction has a simple genetic basis in this species and is consistently inherited as a single-locus recessive trait. We further show that the asexuality-inducing allele exhibits complete linkage to a specific allele at a microsatellite marker: all asexual lines in the field were homozygous for this allele, and the allele cosegregated perfectly with asexual reproduction in our experimental crossings. This novel system of contagious asexuality allows the production of closely related individuals with different reproductive modes, as well as the monitoring of the asexuality-inducing allele in natural and experimental populations.

  16. Aphid parasitoids that occur on wheat crops of Northeast of the Parana State with recovery of Aphidius rhopalosiphi in BrazilParasitoides de pulgões-do-trigo que ocorrem no Norte do estado do Paraná e recaptura de Aphidius rhopalosiphi no Brasil

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    Adriano Thibes Hoshino

    2012-02-01

    Full Text Available Aphids (Hemiptera: Aphididae are the main pest of wheat (Hemiptera: Aphididae in several countries. In Brazil, the Biological Control of Wheat Aphids released millions of aphid parasitoids (Hymenoptera: Braconidae and Aphelinidae on wheat fields and in the present moment the chemical control is rarely necessary. However, since the 80’s few studies was carried out to evaluate the species established in Brazil. For this reason, the aim of this study was to record the species of aphid parasitoids that occur in wheat in the northern region of Parana state, Brazil. Four commercial wheat fields were investigated in the agricultural years of 2008 and 2009. The aphid parasitoids were captured with traps (Moericke and Malaise and aphid mummified were collected. In total, six species of parasitoids were found, Aphidius colemani, A. uzbekistanicus, A. ervi, Aphidius rhopalosiphi, Diaeretiella rapae e Lysiphlebus testaceipes. These results contribute with the register of three exotic species in Parana, and confirm the establishment of A. rhopalosiphi in the country. We emphasize the need for further studies in other regions of the country, as other species introduced also need to have their establishment confirmed.Os pulgões (Hemiptera: Aphididae são pragas de extrema importância em cereais de inverno no mundo todo. No Brasil, o programa Controle Biológico de Pulgões do Trigo liberou milhões de parasitoides (Hymenoptera: Braconidae e Aphelinidae nas áreas tritícolas, reduzindo expressivamente a população da praga, e atualmente raramente o controle químico se faz necessário. Entretanto, desde a década de 80 poucos trabalhos de campo tem sido realizados para verificar as espécies efetivamente estabelecidas no País. Por esta razão, este estudo objetivou registrar as espécies de parasitoides de pulgões ocorrentes em lavouras de trigo na região Norte no Paraná. O trabalho foi realizado em quatro áreas comerciais de trigo, durante as safras

  17. Toxicity of fruit fly baits to beneficial insects in citrus

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    J.P. Michaud

    2003-03-01

    Full Text Available Two fruit fly baits, Nu-Lure®/malathion and GF-120 (Spinosad® were evaluated in the laboratory for non-target impacts on beneficial insects. Nu-Lure/malathion proved attractive and toxic to adults and larvae of the coccinellid species, Curinus coeruleus Mulsant, Cycloneda sanguinea L. and Harmonia axyridis Pallas, a lacewing species, Chrysoperla rufilabris Burmeister. The coccinellids Olla v-nigrum Mulsant, Scymnus sp. and nymphs of the insidious flower bug, Orius insidiosus (Say did not succumb to Nu-Lure baits, even in no-choice situations. Nu-Lure was also attractive and lethal to adults of two aphidophagous flies; Leucopis sp. and the syrphid fly Pseudodorus clavatus (F.. Both Nu-Lure and GF-120 caused significant mortality to the parasitoid wasps, Aphytis melinus De Bach and Lysiphlebus testaceipes Cresson, within 24 h of exposure. However, GF-120 caused no significant mortality to any coccinellid in either choice or no-choice situations, despite considerable consumption of baits. Adults of P. clavatus tended to avoid GF-120, although mortality was significant in no-choice tests. Although larvae and adults of the lacewing C. rufilabris consumed GF-120, mortality was delayed; adults died 48 -96 h post-exposure and those exposed as larvae died two weeks later in the pupal stage. The Nu-Lure bait did not appear palatable to any of the insects, but the high concentration of malathion (195,000 ppm caused rapid mortality to susceptible insects. Nu-Lure bait without malathion also caused significant mortality to flies and lacewings in cage trials. Although GF-120 bait appeared more benign overall, further research efforts are warranted to increase its selectivity for target fly species and reduce its attractiveness to parasitoids and lacewings. I conclude that the Florida "fly free zone" protocol in its current form is not compatible with an IPM approach to commercial citrus production.

  18. An implicit approach to model plant infestation by insect pests.

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    Lopes, Christelle; Spataro, Thierry; Doursat, Christophe; Lapchin, Laurent; Arditi, Roger

    2007-09-07

    Various spatial approaches were developed to study the effect of spatial heterogeneities on population dynamics. We present in this paper a flux-based model to describe an aphid-parasitoid system in a closed and spatially structured environment, i.e. a greenhouse. Derived from previous work and adapted to host-parasitoid interactions, our model represents the level of plant infestation as a continuous variable corresponding to the number of plants bearing a given density of pests at a given time. The variation of this variable is described by a partial differential equation. It is coupled to an ordinary differential equation and a delay-differential equation that describe the parasitized host population and the parasitoid population, respectively. We have applied our approach to the pest Aphis gossypii and to one of its parasitoids, Lysiphlebus testaceipes, in a melon greenhouse. Numerical simulations showed that, regardless of the number and distribution of hosts in the greenhouse, the aphid population is slightly larger if parasitoids display a type III rather than a type II functional response. However, the population dynamics depend on the initial distribution of hosts and the initial density of parasitoids released, which is interesting for biological control strategies. Sensitivity analysis showed that the delay in the parasitoid equation and the growth rate of the pest population are crucial parameters for predicting the dynamics. We demonstrate here that such a flux-based approach generates relevant predictions with a more synthetic formalism than a common plant-by-plant model. We also explain how this approach can be better adapted to test different management strategies and to manage crops of several greenhouses.

  19. Effects of heat shock on resistance to parasitoids and on life history traits in an aphid/endosymbiont system.

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    Luis Cayetano

    Full Text Available Temperature variation is an important factor determining the outcomes of interspecific interactions, including those involving hosts and parasites. This can apply to variation in average temperature or to relatively short but intense bouts of extreme temperature. We investigated the effect of heat shock on the ability of aphids (Aphis fabae harbouring protective facultative endosymbionts (Hamiltonella defensa to resist parasitism by Hymenopteran parasitoids (Lysiphlebus fabarum. Furthermore, we investigated whether heat shocks can modify previously observed genotype-by-genotype (G x G interactions between different endosymbiont isolates and parasitoid genotypes. Lines of genetically identical aphids possessing different isolates of H. defensa were exposed to one of two heat shock regimes (35°C and 39°C or to a control temperature (20°C before exposure to three different asexual lines of the parasitoids. We observed strong G x G interactions on parasitism rates, reflecting the known genetic specificity of symbiont-conferred resistance, and we observed a significant G x G x E interaction induced by heat shocks. However, this three-way interaction was mainly driven by the more extreme heat shock (39°C, which had devastating effects on aphid lifespan and reproduction. Restricting the analysis to the more realistic heat shock of 35°C, the G x G x E interaction was weaker (albeit still significant, and it did not lead to any reversals of the aphid lines' susceptibility rankings to different parasitoids. Thus, under conditions feasibly encountered in the field, the relative fitness of different parasitoid genotypes on hosts protected by particular symbiont strains remains mostly uncomplicated by heat stress, which should simplify biological control programs dealing with this system.

  20. Evolution of reproductive mode variation and host associations in a sexual-asexual complex of aphid parasitoids

    Directory of Open Access Journals (Sweden)

    Sandrock Christoph

    2011-12-01

    Full Text Available Abstract Background The Lysiphlebus fabarum group is a taxonomically poorly resolved complex of aphid parasitoids, presently split into three described species that comprise sexual (arrhenotokous and asexual (thelytokous lineages of unknown relationship. Specifically, it is unclear how asexuals evolved from sexuals in this system, to what extent reproductive modes are still connected by genetic exchange, how much the complex is structured by geography or by host-associated differentiation, and whether species designations are valid. Using a combination of population genetic and phylogenetic approaches, we addressed these issues in a comprehensive sample of parasitoid wasps from across Europe. Results Asexual reproduction predominated in parasitoids of the L. fabarum group, with asexual populations exhibiting high genotypic diversity. Sexual populations were only common in southern France; elsewhere sexual reproduction was restricted to specific aphid hosts. Although reproductive modes were aggregated on the mitochondrial genealogy and significantly differentiated at nuclear microsatellite loci, there was clear evidence for genetic exchange, especially on hosts attacked by sexual and asexual parasitoids. The microsatellite data further revealed that parasitoids collected from certain host aphids were significantly differentiated, yet the mitochondrial sequence variation across the entire L. fabarum group did not exceed 1.32% and exhibited a very shallow topology. Morphological characters used for delineation of described species were found to be phylogenetically non-conservative. Conclusions Our results suggest that the sexual-asexual L. fabarum group represents a young complex of lineages with incomplete isolation between reproductive modes. We propose three mechanisms of genetic exchange that may jointly explain the high genotypic diversity observed in asexual parasitoids: (i the formation of new asexual lineages via 'contagious parthenogenesis

  1. Adaptation of the dwarf forms of soybean aphid, Aphis glycines to environment and impact on soybean yield%大豆蚜对环境的适应及对大豆产量的影响

    Institute of Scientific and Technical Information of China (English)

    许国庆; 陈彦; 王兴亚; 刘培斌; 徐蕾; 赵彤华

    2011-01-01

    The population dynamics of the dwarf form of the soybean aphid, Aphis glycines Matsumura, was investigated in 2009 and 2010 in Xiuyan County, eastern Liaoning, one of the main soybean production areas in China. Fungal parasitism of this pest by Verticillium lecanii( Zimmerman) Viegas and Lysiphlebus fabarum Marshall and predation on it by Harmonia axyridis(Pallas) were also investigated. In addition, research was conducted on the effect on this species of rainfall, and on its impact on soybean yield. The results indicate that the earliest damage to soybean plants occurred in mid-June. Heavy infestations of aphids occurred in late July and early August with densities of up to 80 722 aphids per hundred plants. Normal aphids excreted significantly more honey-dew than dwarf forms. Dwarf forms had a lower incidence of parasitism by V. Lecanii than normal forms. However, normal forms had a higher incidence of parasitism by L fabarum(43. 41% ) than dwarf forms(0. 58% ) . The 3rd larval stage of H. Axyriiis had a predation rate on normal and dwarf aphids of 80. 24% and 36. 36% respectively. Dwarf forms were less affected by rainfall than normal forms. Moreover, a One-Way ANOVA indicated no significant relationship between the number of dwarf aphids per plant and yield(F = 0.378; df/=7,l; P>0.05).%2009-2010年,以辽东山区大豆主产区岫岩县作为试验点,系统调查了大豆蚜Aphis glycines Matsumura 正常型蚜和小型蚜的种群动态,研究了蜡蚧轮枝菌Verticillium lecanii( Zimmerman) Viegas、豆柄瘤蚜茧蜂Lysiphlebus fabarum Marshall、异色瓢虫Harmonia axyridis( Pallas)对大豆蚜正常型蚜和小型蚜的寄生与捕食作用;另外,也研究了降雨对小型蚜和正常型蚜的冲刷作用,以及小型蚜对大豆产量的影响等.研究结果表明,7月上中旬为大豆蚜小型蚜发生初期,7月下旬-8月上旬为小型蚜发生高峰期,2010年小型蚜平均蚜量达10000头/百株以上.此外,通过比较大豆蚜正常