Neotropical Entomology 35(5): 654-659(2006) Efeito da Idade dos Ovos de Spartocera dentiventris (Berg) (Hemiptera: Coreidae) no Parasitismo por Gryon gallardoi (Brethes) (Hymenoptera: Scelionidae)RESUMO -Visando avaliar o efeito da idade dos ovos de Spartocera dentiventris (Berg) no parasitismo por Gryon gallardoi (Brethes), foram expostos grupos de 12 ovos de 2, 3, 4, 5, 6, 7, 8, e 12 dias de idade para uma fêmea de G. gallardoi em um tubo de ensaio, sendo esta observada por 2h. Após, os ovos foram individualizados e incubados (25 ± 1°C; fotoperíodo de 12h) até a emergência dos adultos. Para a avaliação da idade preferencial, grupos de 12 ovos de 1, 3, 5, 7 e 12 dias de idade foram expostos, simultaneamente, para uma fêmea do parasitóide por 2h. Posteriormente, os grupos foram individualizados e incubados até ser confirmado o parasitismo. Em todas as idades testadas verificouse parasitismo em 88,5 ± 2,64% dos ovos oferecidos, com diminuição no percentual de emergência com o aumento da idade (P < 0,01). O tempo de desenvolvimento aumentou com a idade dos ovos (P < 0,01), sendo que os machos se desenvolveram mais rapidamente. A razão sexual, em todas as idades testadas foi desviada para fêmeas (0,49:1) e a proporção de machos não variou com a idade do hospedeiro (P > 0,05). Quando os grupos de ovos foram expostos simultaneamente, a fêmea preferiu os ovos de um e três dias de idade. Os resultados indicaram preferência de G. gallardoi por ovos mais jovens de S. dentiventris podendo a idade exercer efeito negativo no tempo de desenvolvimento e na emergência da prole.PALAVRAS-CHAVE: Insecta, parasitóide de ovos, interação hospedeiro-parasitóide ABSTRACT -To evaluate the effect of egg age of Spartocera dentiventris (Berg) on the parasitism by Gryon gallardoi (Brethes), groups of 12 eggs of 2, 3, 4, 5, 6, 7, 8, and 12 days old were exposed to one female of G. gallardoi on a test tube, with the wasp observed for 2h subsequently. Later, the eggs were individualised and incubated (25 ± 1°C; 12h photoperiod) until adult emergence. To identify the preferred age, groups of 12 eggs of 1, 3, 5, 7 and 12 days of age were simultaneously exposed to a parasitoid female on an arena for 2h. These groups were also individualised and incubated until parasitism was confirmed. On all ages tested parasitism was at about 88.5 ± 2.64%, with a reduction in adult parasitoid emergence with age increasing (P < 0.01). The development time increased with increasing egg age (P < 0.01), with males developing faster. Parasitoid sex ratio for all ages tested was female-biased (0.49:1), with the proportion of males invariant with host age (P > 0.05). When the egg groups were exposed simultaneously, the female preferred eggs one and three days old. The results indicate a preference of G. gallardoi for younger eggs of S. dentiventris, with host egg age exerting a negative effect on development time and offspring emergence of the parasitoid.KEY WORDS: Insecta, egg parasitoid, host-parasitoid interaction age, insect egg chemical composition changes ra...
A mass marking-recapture experiment was carried out to study the dispersal of Gryon gallardoi (Brethes) (hymenoptera: scelionidae) in tobacco crops. parasitoids emerged in the laboratory were marked with dye powder. six separate field trials were conducted in Jan/feb 2002 involving the simultaneous release of marked parasitoids. Dispersal was determined by the recapture of individuals in sets of sticky and moericke traps arranged in three concentric circles arranged at 1.4 m intervals from the central point of release. traps were checked 4, 8, 24, 28, 32 and 48 h after parasitoid release and weather data were recorded at 2-h intervals from 9 to 17 h at the site. of the 699 marked parasitoids released, 91 were recaptured (13.02%). fewer females were recaptured in the late afternoon, suggesting they are less active than males after dusk. G. gallardoi recaptures were not associated with average wind direction in any trials. After eight hours of release, recaptures occurred mostly in the traps farthest from the release point, suggesting that the experimental area was small in relation to the dispersal capacity of the parasitoid. fitting a 4-h-after-release density-distance curve to a geometric model and considering a daily activity of 12 h, the female dispersal capacity was estimated to be at least 7.6 m/day. the values reported here must be considered as indicative of the potential for active dispersal under the particular experimental conditions of these trials. it is possible that G. gallardoi may disperse downwind much farther than the distance recorded in this study.Keywords: insecta, parasitism, Gryon gallardoi, movement, marking-recapture. Palavras-chave: insecta, parasitismo, Gryon gallardoi, movimento, marcação-recaptura. RESUMO
This study aimed to evaluate the influence of Spartocera dentiventris (Berg) (Hemiptera: Coreidae) egg quality (regarding age, size and superparasitism) on male and female body size of Gryon gallardoi Bre`thes (Hymenoptera: Scelionidae). It was also analysed host size influence on offspring sex choice and female oviposition order (within egg groups). Groups of 12 eggs, 2, 3, 4, 5, 6, 7, 8, and 12 days old were individually exposed to a female parasitoid for 2 h, and the order of each egg parasitisation was recorded. Size of adult parasitoids (head width and tibia length of the second leg pair), and parasitised and superparasitised host eggs were measured. Sexual dimorphism related to size (SDs), was estimated through a model II linear regression. Females have a larger head width but a smaller tibia length. Parasitoid adult size is significantly related to host age and size. Within an egg group, females did not exhibit preference for any egg size category either to start oviposition or to oviposit male or female eggs. The body size of both sexes diminished with host aging. There was a positive response in both sexes to host size increasing. Estimated SDs diminished with host aging and increased with host volume augmentation. The results suggest that adult body size of G. gallardoi, as well as size differences between males and females, are strongly associated to host quality.
During surveys of natural enemies of the leaf-footed bugs Holhymenia rubiginosa Breddin and Anisoscelis foliacea Fabricius in Rio Grande do Sul State, Brazil, two species of primary egg parasitoids belonging to the genus Gryon were reared from these hosts. One of these Gryon species was identified as G. chrysolaum Walker, a species unknown since its description nearly 170 years ago. The second Gryon species reared was G. vitripenne Masner. These rearings represent the first host records for this species. Levels of parasitism by G. chrysolaum were 35% and 53% on H. rubiginosa and A. foliacea respectively. Additional specimens reared were a Neorileya and a Telenomus species. After examination of unidentified Gryon specimens in the Natural History Museum, London, a further three specimens were located, from Brazil and Mexico. Data on hosts and localities of all known specimens of G. chrysolaum are presented, and the species is redescribed and compared with its closest known relatives. The female is described for the first time.
Biology of Holhymenia rubiginosa Breddin (Hemiptera: Coreidae) on Passifl ora alata (Passifl oraceae)ABSTRACT -The biology of Holhymenia rubiginosa Breddin is described on sweet-passion-fruit, Passifl ora alata, and the developmental time, viability and thermal requirements of the egg stage, the developmental time and mortality of the nymphal stage, and adult longevity and reproductive parameters were assessed. Insects were reared at laboratory controlled conditions (25 ± 1°C, 65 ± 10% RH, photophase 12h) on branches of P. alata, 20% honey solution and pollen. The lower thermal threshold (10.8°C) and thermal requirements (140.8 DD) for egg development were determined using four temperatures (17, 21, 25 and 30°C). The average egg development time (days) and viability were 25.4 ± 0.45, 88%; 13.2 ± 0.28, 88%; 8.8 ± 0.16, 94%; and 7.7 ± 0.17, 92%, at 17, 21, 25 and 30 ± 1°C, respectively. When reared at 25 ± 1°C, the fi rst instar had the shortest development time (4.0 ± 0.02 days) and the second the longest (15.7 ± 3.50 days), which also had the highest mortality (75%). Males and females had similar longevity (185.3 ± 17.52 days for females and 133.6 ± 18.94 days for males). Females mated 33.0 ± 7.71 times, with a mean duration of 99.0 ± 9.25 min, laying 11.5 ± 2.55 eggs/female. Periods of pre-oviposition, oviposition and post-oviposition were respectively 96.4 ± 18.08; 88.5 ± 23.48 and 19.3 ± 12.18 days.KEY WORDS: Development, passion-fruit, thermal requirement, reproductive parameter RESUMO -A biologia de Holhymenia rubiginosa Breddin, em maracujazeiro-doce, Passifl ora alata é descrita e são avaliados o tempo de desenvolvimento, a viabilidade e as exigências térmicas embrionárias, a duração e a mortalidade na fase ninfal, assim como a longevidade e os parâmetros reprodutivos. Os insetos foram criados em laboratório, em condições controladas (25 ± 1°C, 65 ± 10% UR, fotofase 12h), alimentados com ramos de P. alata e solução de mel a 20% e pólen. A temperatura base estimada para a fase embrionária foi de 10,8°C e a constante térmica 140,8 GD, determinadas para fase de ovo usando quatro temperaturas (17, 21, 25 e 30 ± 1°C). A duração média, em dias, e a viabilidade da fase de ovo foram de 25,4 ± 0,45 (88%); 13,2 ± 0,28 (88%); 8,8 ± 0,16 (94%) e 7,7 ± 0,17(92%), nas temperaturas de 17, 21, 25 e 30 ± 1°C, respectivamente. Quando criado a 25 ± 1°C, o primeiro ínstar teve o menor tempo de desenvolvimento (4,01 ± 0,02 dias) e o segundo o mais longo (15,7 ± 3,50 dias), além de ser o que apresentou maior mortalidade (75%). Machos e fêmeas tiveram longevidade similar (185,3 ± 17,52 dias para fêmeas e 133,6 ± 18,94 dias para machos). Fêmeas copularam 33,0 ± 7,71 vezes, com duração média de 99,0 ± 9,25 minutos, ovipositando 11,5 ± 2,55 ovos. Períodos de pré-oviposição, oviposição e pós-oviposição foram, respectivamente, 96,4 ± 18,08; 88,5 ± 23,48 e 19,3 ± 12,18 dias. PALAVRAS-CHAVE: Desenvolvimento, maracujazeiro, exigência térmica, parâmetro reprodutivo No cenário mundial, o Brasil destaca-se como maior produtor de maracujá...
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