309 resultados para parasitoids
Resumo:
In a previous study, we observed no spatial genetic structure in Mexican populations of the parasitoids Chelonus insularis Cresson (Hymenoptera: Braconidae) and Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) by using microsatellite markers In the current study, we Investigated whether for these important parasitoids of the fall armyworm (Lepidoptera: Noctuidae) there is any genetic structure at a larger scale Insects of both species were collected across the American continent and their phylogeography was Investigated using both nuclear and mitochondria] markers Our results suggest an ancient north-south migration of C insularis, whereas no clear pattern] could be determined for C sonorensis. Nonetheless, the resulting topology indicated the existence of a cryptic taxon within this later species. a few Canadian specimens determined as C. sonorensis branch outside a clack composed of the Argentinean Chelonus grioti Blanchard, the Brazilian Chelonus flavicincta Ashmead, and the rest of the C sonorensis individuals The individuals revealing the cryptic taxon were collected from Thichoplusia in (Hubner) (Lepidoptera. Noctuidae) on tomato (Lycopersicon spp) and may represent a biotype that has adapted to the early season phenology of its host. Overall, the loosely defined spatial genetic structure previously shown at a local fine scale also was found at the larger scale, for both species Dispersal of these insects may be partly driven by wind as suggested by genetic similarities between Individuals coming from very distant locations.
Resumo:
The effects of wing shape, wing size, and fluctuating asymmetry in these measures oil the field fitness of T. nr. brassicae and T. pretiosum were investigated. Trichogramma wasps mass-reared on eggs of the factitious host Sitotroga cerealella were released in tomato paddocks and those females ovipositing on Helicoverpo spp. eggs were recaptured. Comparisons of the recaptured group with a sample from the release population were used to assess fitness. Wing data were obtained by positioning landmarks on mounted forewings. Size was then measured as the centroid size computed from landmark distances, while Procrustes analysis followed by principal component analysis was used to assess wing shape. Similar findings were obtained for both Trichogramma species: fitness of wasps was strongly related to wing size and some shape dimensions, but not to the asymmetries of these measures. Wasps which performed well in the field had larger wings and a different wing shape compared to wasps from the mass reared population. Both size and the shape dimensions were linearly associated with fitness although there was also some evidence for non-linear selection on shape. The results suggest that wing shape and wing size are reliable predictors of field fitness for these Trichogramma wasps.
Resumo:
Foi feito um levantamento da fauna de Hymenoptera parasitóides em um transecto eucalipto/vegetação nativa/eucalipto, em Ipaba, Minas Gerais, no período de março de 1997 a março de 1998, com armadilhas Malaise. Foram coletados indivíduos de nove superfamílias (Ceraphronoidea, Chalcidoidea, Chrysidoidea, Cynipoidea, Evanioidea, Ichneumonoidea, Proctotrupoidea, Platygastroidea e Vespoidea), distribuídos em 26 famílias.
Resumo:
The objective of the study was to report the first occurrence of the parasitoid Brachymeria podagrica in pupae of Ophyra aenescens, a fly of medical-sanitary importance. Human feces was used as bait to collect the insects. In the study 20 pupae of Ophyra aenescens (Wiedemann) (Diptera: Muscidae) were obtained, of which 20% of the total yielded the parasitoid Brachymeria podagrica (Hymenoptera: Chalcididae).
Resumo:
Paracrias strii Schauff, 1985 and P. ceratophaga Palmieri & Hansson sp. nov. are first record in Brazil and both are associated with Ceratopus Schoenherr larvae (Coleoptera, Curculionidae) reared from syconia of two species of fig-trees. Both Paracrias species are diagnosed and illustrated. Males of P. ceratophaga sp. nov. are described. The association of Paracrias with weevil larvae is briefly discussed.
Resumo:
The aim of this contract was to finalise in vitro rearing on artificial diets of entomophagous insects useful to control insect pests mainly in greenhouses through an analytical and rational approach. The work focuses on the development and optimisation of artificial diets for one coccinellid (Harmonia axyridis), two heteropteran predators (Orius laevigatus, Dicyphus tamaninii), and a braconid parasitoid of aphids (Aphidius ervi). The definition of the artificial diets was based on biochemical analyses of their natural food (aphids) or substitution food for the predators (Ephestia kuehniella eggs). Reliable quality control parameters of the entomophages produced were used in order to adjust dietary composition and formulation of the different diets tested.
Resumo:
This study evaluated the parasitoid-aphid-plant associations in Brazil with the objective of developing a useful research database for further studies of aphid parasitoid ecology and aphid management. The original material was obtained from collections made in Paraná, Rio Grande do Sul, Minas Gerais, and São Paulo states. The published information on the Aphidiinae in Brazil is revised. The general features of the target parasitoid fauna of Central and South America is summarized and promising biological control programs of some aphid species in Brazil is discussed.
Resumo:
The aim of this study was to verify the duration of the development period, number of parasitoids produced per pupa, parasitism rate and sex ratio of Nasonia vitripennis (Hymenoptera, Pteromalidae), when they were exposed to a single host: Chrysomya megacephala (Diptera, Calliphoridae). One pupa was exposed in glass tubes to different numbers of female parasitoids (1, 3, 5, 7, 9 and 11) during 48 h. Twenty replications/treatment were used, under controlled conditions (T= 27 °C day/ 25 °C night, 60 ± 10% RH). Statistical analysis of the data was made using the ANOVA test and the "a posteriori" comparisons were made using the Tukey-HSD test (both tests with a significance level of 5%). The duration of the development period was longer in treatments where a higher density of females per host was used. When five females per host were used, the mean number of parasitoids that emerged per pupa was higher. The data showed a tendency to a decrease in the amount of parasitoids emerged per host, especially of female, when used high quantities of female per host. Higher parasitism rates were observed in the 3:1 and 5:1 treatments and an increase in the percentage of unviable pupae was observed, probably due to an increase of female densities in the treatments, possibly a consequence of superparasitism.
Resumo:
Parasitoids of the family Ichneumonidae (Hymenoptera) were obtained during an inventory of Lepidoptera larvae caught feeding in the wild on Croton floribundus (Euphorbiaceae). The Lepidoptera larvae were collected from host plants along trails inside three preserved forest areas in the Brazilian state of São Paulo. Fifteen different species of Ichneumonidae belonging to five subfamilies (Banchinae, Campopleginae, Cremastinae, Mesochorinae and Metopiinae) were obtained. Seven species of Ichneumonidae were reared from leaf rollers: Meniscomorpha sp. (Banchinae) and Leurus caeruliventris (Cresson) (Metopiinae) from Dichomeris sp. (Gelechiidae); Mesochorus sp.1 (Mesochorinae) [as a parasitoid of Hypomicrogaster sp. (Braconidae, Microgastrinae)], Campoplex sp. (Campopleginae) and Leurus sp. from Olethreutinae sp. (Tortricidae); Sphelodon annulicornis Morley (Banchinae) and Eutanygaster brevipennis Cameron (Cremastinae) were also reared from two unidentified species of Gelechiidae. The other eight species were reared from the larvae of exposed feeders: Diradops sp. (Banchinae) from Miselia albipuncta Hampson (Noctuidae), Casinaria sp. (Campopleginae) from Hymenomima conia Prout (Geometridae), Charops sp. (Campopleginae) from Bagisara paulensis Schaus (Noctuidae) and Oxydia vesulia (Cramer) (Geometridae), two species of Hyposoter Förster (Campopleginae) from Semaeopus sp. (Geometridae) and H. conia, two species of Microcharops Roman (Campopleginae) from B. paulensis and an unidentified species of Limacodidae and Mesochorus sp. 2 [reared from what was probably Aleiodes sp. (Braconidae, Rogadinae)] from an unidentified species of Noctuidae.
Resumo:
Host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum in laboratory. This research aimed to evaluate the host preference of the egg parasitoids Telenomus remus and Trichogramma pretiosum. Trials were carried out in laboratory, under controlled environmental conditions (25 ± 2ºC temperature; 70 ± 10% RH; and 14 h photophase). The parasitoid searching behavior was evaluated based on the distribution (%) of eggs parasitized by each parasitoid, on egg masses of each host species. Results showed the host preference of T. remus by Spodoptera cosmioides eggs. T. pretiosum, reared in A. gemmatalis eggs, choose to parasitize always eggs of the host where the parasitoid had been reared. The egg preference was not observed when T. pretiosum was reared in S. frugiperda eggs. These results show that, in general, host preference of T. remus is less influenced by the host where it is developed than T. pretiosum. Host preference is an important parameter for biological control programs because more than one pest species may occur in the field, different from those where they were reared in the laboratory.
Resumo:
Mortality of Plutella xylostella (Lepidoptera, Plutellidae) by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758) (Lepidoptera, Plutellidae) larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae), in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae), L3 (Lm = medium larvae), L4 (Ll = large larvae), pre-pupae and pupae (P). Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875) (Hymenoptera, Ichneumonidae), Oomyzus sokolowskii (Kurdjumov, 1912) (Hymenoptera, Eulophidae), Cotesia plutellae (Kurdjumov, 1912) (Hymenoptera, Braconidae) and an unidentified species of Chalcididae (Hymenoptera). Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.
Resumo:
Egg parasitoids of Edessa meditabunda (Fabricius) (Pentatomidae) in lettuce crop. This study evaluated the occurrence of parasitoids in eggs of the stink bug, Edessa meditabunda (Fabricius, 1794) (Heteroptera, Pentatomidae) found on lettuce crop in Mato Grosso State, Brazil. Samples were collected in the vegetable garden "Cheiro Verde", in the municipality of Tangará da Serra, in curly lettuce. A bed of lettuce was selected randomly, where the eggs of E. meditabunda were collected. Five-hundred and seventy eight eggs of E. meditabunda were collected, 86.3% of them parasitized by Telenomus podisi Ashmead, 1893 (Hymenoptera, Platygastridae), Trissolcus urichi Crawford, 1913 (Hymenoptera, Platygastridae) and Neorileya albipes Girault, 1913 (Hymenoptera, Eurytomidae), representing respectively 57.0%, 38.2% and 4.8% of the emerged individuals. This is the first record of these three species parasitizing eggs of E. meditabunda in lettuce.
Resumo:
Fruit flies (Diptera, Tephritidae) and their parasitoids on cultivated and wild hosts in the Cerrado-Pantanal ecotone in Mato Grosso do Sul, Brazil. Information on frugivorous flies in cultivated or wild host plants and their parasitoids in the Cerrado-Pantanal ecotone in Aquidauana, Mato Grosso do Sul is presented and discussed. Fruit fly samples were collected weekly in specific fruit trees, and McPhail® traps were installed in the same trees for a period of two years. The fruit flies infested ripe and unripe fruits of Averrhoa carambola L., Schoepfia sp., Psidium guajava L. and Pouteria torta (Mart.) Radlk and mature fruits of Anacardium occidentale L. and Inga laurina (Sw.) Willd. Nineteen fruit fly species were obtained with the combination of sampling methods (collecting fruits and trapping), nine of them obtained with both methods, five found only in fruits and five only in traps. This is the first record of Anastrepha striata Schiner in a species of Sapotaceae, as well as for A. castanea Norrbom and A. daciformes Bezzi in Schoepfia sp. (Olacaceae), and for A. distincta Greene in fruits of P. guajava in the state of Mato Grosso do Sul. Fruit collections simultaneously associated with capture of fruit flies by McPhail traps in the same host plants are essential to understand the diversity of fruit flies and their relationship with hosts and parasitoids. Species of Braconidae and Pteromalidae were recovered, where Doryctobracon areolatus (Szépligeti) was the most abundant parasitoid in larvae of tephritids infesting both cultivated and wild host fruits.
Resumo:
Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas. Hosts of parasitoids in urban areas may suffer from a double threat of habitat destruction by urbanization and parasitism pressure. Moreover, the parasitoids themselves might be at risk if they are specialists. Here, we studied whether Atta robusta (Hymenoptera, Formicidae), which is on the red list of Brazilian threatened species, suffers from higher parasitism pressure in an urban area compared to a natural one. In addition, we determined whether their specialist parasitoids, Eibesfeldtphora breviloba and Myrmosicarius exrobusta (Diptera, Phoridae), are in risk and evaluated whether they are influenced by habitat structure, temperature, humidity, ant traffic, and time of the day. The study was carried out in an urban park and in a natural protected area in the city of Rio de Janeiro. In each site we chose an open area and a closed area (forest) and sampled nine nests in each area. We found that parasitism pressure was similar in urban and natural areas, with the same two parasitoid species present in both areas. The main difference was related to habitat structure, since M. exrobusta was mainly present in open areas while E. breviloba was almost exclusively found in closed areas. Myrmosicarius exrobusta was not present during the hottest midday times, and its abundance was negatively correlated to vapor pressure deficit. These results suggest that green areas can be an important component in efforts to conserve diversity in urban areas. However, the complexity of the habitats in those areas is a fundamental issue in designing urban parks.