895 resultados para rearing


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We developed a method for rearing larvae of Africanized bees under laboratory conditions to determine the amount of diet needed during larval development to obtain a worker bee. We started with larvae 18-24 h old, which were transferred to polyethylene cell cups and fed for five days. We found that the amount of diet needed for successful larval development was: 4, 15, 25, 50, and 70 mu L during the first to fifth days, respectively. The survival rate to the adult stage was 88.6% when the larvae received the daily amount of diet divided into two feedings, and 80% when they received only one feeding per day. The adult weight obtained in the laboratory, when the larvae received the daily amount of diet in a single dose, did not differ from those that were developed under field conditions (our control). All adults that we obtained in laboratory appeared to be normal. This technique has the potential to facilitate studies on brood pathogens, resistance mechanisms to diseases and also might be useful to test the impacts of transgenic products on honey bee brood.

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Color, pH, shear force, water-holding capacity, chemical composition, cholesterol content, and fatty acid profile from conventional, free-range and alternative broiler breast meat were determined in order to evaluate differences in the quality of broiler meat produced under different systems. Broilers reared in a conventional system had the highest lipid content (1.3%) but lower proportions of polyunsaturated (17.3%) and omega-3 fatty acids (0.3%) (p<0.05) compared to free-range and alternative broilers. On the other hand, free-range broilers had a lower cholesterol content (48.6 mg center dot 100 g(-1)) and lower pH (5.7 1) while broilers raised in an alternative system had a higher shear force (2.33 kgf) and lower yellowness value (b* value = 3.15) when compared to the other rearing systems (p<0.05).

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The objective of this research was to describe the biological and morphometric aspects of the parica tree defoliator, Syssphinx molina (Cramer), and make recommendations about the insect rearing. The life cycle was 62.9 days with mean periods for the egg, larval, pre-pupal and pupal stages of 5.6, 31.1, 2.2 and 16.6 days respectively. The pupal viability was 60.5% for females and 48.6% for males. The sexual ratio was 0.5 with mean production of 182.3 ± 2.2 eggs per female and egg viability of 24.3%. The mean longevity was 7.9 ± 2 and 8.1 ± 3 days for females and males respectively. Other parameters were also observed and compared with description of other Saturniidae species.

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The sandfly Lutzomyia evansi from a focus of visceral leishmaniasis in northern Colombia was reared and maintained under laboratory conditions for five generations. The average time for total development was 41.8 days (range = 35.1- 49.6) at 25 oC and 89-95% of relative humidity. The mean number of eggs laid was lower in laboratory bred females either in pots (13.2 eggs/female) or vials (29.9 eggs/female) than in wild caught females (33.4 eggs/female). Immature mortality, mainly due to fungal and mite contamination, was higher during the first two instars than in the remaining immature stages. Adults were robust and healthy although difficult to feed on hamster or chick skin membrane. In summary, Lu. evansi is a colonizable species but requires specific conditions.

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The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7°C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory

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We examined changes in the array of antennal sensilla of three species of Triatominae (Triatoma infestans, Rhodnius prolixus, and R. pallescens) following their establishment for different periods in laboratory culture. In each case, the laboratory colonies were compared with conspecific samples taken directly from the field, by quantitative analysis of the sensilla arrays on the three distal segments of the antenna in terms of the densities of three types of chemoreceptors (basiconics and thick and thin walled trichoids) and one type of mechanoreceptor (bristles). Sensilla densities were compared by ANOVA or non-parametric tests, and by multivariate discriminant analysis. Strains of the same species reared in different laboratories showed significant differences in their sensilla arrays, especially when compared to field-collected material from the same geographic origin. A Bolivian strain of T. infestans reared in the laboratory for 15 years and fed at monthly intervals, showed greatest differences from its conspecific wild forms, especially in terms of reductions in the number of chemoreceptors. By contrast, an Argentine strain of T. infestans reared for 25 years in the laboratory and fed weekly, showed a relative increase in the density of mechanoreceptors. A Colombian strain of R. prolixus reared for 20 years and fed weekly or fortnightly, showed only modest differences in the sensilla array when compared to its wild populations from the same area. However, a Colombian strain of R. pallescens reared for 12 years and fed fortnightly, did show highly significant reductions in one form of chemoreceptor compared to its conspecific wild populations. For all populations, multivariate analysis clearly discriminated between laboratory and field collected specimens, suggesting that artificial rearing can lead to modifications in the sensory array. This not only supports the idea of morphological plasticity in these species, but also suggests caution in the use of long-established laboratory material for experimental studies designed to extrapolate the natural behaviour and physiology of these species.

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The embryonic development of human lice was evaluated according to the changes in the morphology of the embryo observed through the transparent chorion. Based on ocular and appendage development, three stages of embryogenesis were established: early, medium, and late. Influence of temperature and relative humidity (RH) on the laboratory rearing of Pediculus humanus capitis eggs was assessed. The optimal ranges for temperature and RH were 27-31°C and 45-75%. The susceptibility of human louse eggs to insecticide spinosad (a macrocyclic lactone) was assessed by immersion method. The results showed similar susceptibility to spinosad in early, medium, and late stages of head lice eggs. In addition, this study showed similar susceptibility of head and body lice eggs to spinosad, an insecticide that has not been used as pediculicide in Argentina (lethal concentration 50: 0.01%).

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Chagas disease is a major public health issue and is mainly spread by Triatominae insects (Hemiptera: Reduviidae). Rhodnius prolixus is the main vector species in Northern South America. Host-seeking behaviour in R. prolixus is mediated by different compounds that are produced by and emanate from the host or microbiota on the host's skin. We tested the behavioural responses of sylvatic first filial generation (F1) and colony insects to extracts of human skin with a dual choice olfactometer. In addition, we compared the antennal phenotypes in both populations. No statistical differences were found between the two populations at the behavioural level. Both showed a preference for face and feet extracts and this effect was abolished for face extracts after treatment with an antibacterial gel. The observation of the antennal phenotype showed that there were differences between both groups in the total length, total surface area and number and density of bristles. However, the number and density of chemoreceptive sensilla (basiconic and thin and thick-walled trichoids) and the total density of sensilla did not show statistically significant differences. These results demonstrate that colony insects, which have only been fed with living hens for the last 30 years, are attracted by human skin extracts in a similar way as F1 sylvatic insects.

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A diet which does not desiccate was developed for rearing various ant species. this diet was found to be very attractive forIridomyrmex humilis. Monomorium pharaonis andWasmannia auropunctata in which species it permitted the rearing of colonies for long periods and the regular production of sexuals. Nous présentons la recette d'une nourriture artificielle élaborée pour élever des fourmis en laboratoire. Cette nourriture ne se dessèche pas et s'est avérée adéquate pour l'élevage de plusieur espèces telles queIridomyrmex humilis, Monomorium pharaonis etWasmannia auropunctata. Des sexués mâles et femelles ont été régulièrement produits dans ces sociétés.

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Oryzaephilus surinamensis is one of most common insect pest of grains and a variety of stored products, and has been found in high numbers in almost all storage facilities. However, laboratory mass rearing of this insect for bioassays is not a simple task, mainly because of its feeding behavior, small size, and high mobility. Thus, the aim of this work was to develop a simple and efficient laboratory rearing method for O. surinamensis, using wheat kernels milled into different granulometry to obtain large number and standardized population at different life stages for bioassays. The adults were collected from storage grain facilities in the southern region of Brazil and 100 specimens were placed inside glass jars with wheat kernels milled at different grades and kept at 25±0.5ºC and 65±5% relative humidity. The insects were allowed to copulate and lay eggs for 10 days and then removed. The number of eggs, larvae, and pupae was counted at five-day intervals; longevity of the second generation adults was evaluated. The kernels milled at grade 20 were the best medium for offspring production: 89% of eggs by the 5th day; 30.5% larvae by the 10th day; 43% pupae by the 30th day and 63.4% adults at the 46th day. The adults survived up to 450 days. Culturing O. surinamensis under the described conditions, transferring the parental adults by the 10th day after infestation and replacing the media when population builds up will produce enough insects of each stage for various laboratory bioassays.

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Studies in the laboratory tested the suitability of synthetic wool string, cotton string, cheesecloth, and commercial cotton ball as artificial oviposition substrates for the small green stink bug, Piezodorus guildinii (Westwood) (Heteroptera, Pentatomidae). In confined cages, 54% of total egg masses was laid on synthetic wool string, 31% on cotton string, and only 15% on cheesecloth. In an additional test, the best substrate selected, synthetic wool string, received 92% of egg masses compared to 8% on the commonly used substrate, cotton ball. Synthetic wool string received the most egg masses of any size, in particular those in the range 11-20 eggs/mass. Because the eggs of P. guildinii are laid in two parallel double rows, the egg masses fit the wool string perfectly.

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New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory. Here we show, for the first time, that larvae of the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), can be successfully reared in a cohort-based manner with virtually no cannibalism. FAW larvae were reared since the second instar to pupation in rectangular plastic containers containing 40 individuals with a surprisingly ca. 90% larval survivorship. Adult females from the cohort-based method showed fecundity similar to that already reported on literature for larvae reared individually, and fertility higher than 99%, with the advantage of combining economy of time, space and material resources. These findings suggest that the factors affecting cannibalism of FAW larvae in laboratory rearings need to be reevaluated, whilst the new technique also show potential to increase the efficiency of both small and mass FAW rearings.

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Thermal hygrometric requirements for the rearing and release of Tamarixia radiata (Waterston) (Hymenoptera, Eulophidae). Tamarixia radiata is the main agent for the biological control of Diaphorina citri in Brazil with a parasitism rate ranging from 20 to 80%. This study investigated the influence of temperature on the development, fecundity and longevity of adults of T. radiata and the effect of relative humidity (RH) on their parasitism capacity and survival rate in the pre-imaginal period. The effect of temperature was assessed in the range between 15 and 35 ± 1ºC, 70 ± 10% RH, and a 14-h photophase. The RH effect was evaluated in the range from 30 to 90 ± 10%, temperature at 25 ± 1ºC, and photophase of 14-h. At 25ºC, circa 166.7 nymphs were parasitized, the highest parasitism capacity observed compared to other treatments. The longest longevity of females was observed at 25ºC, although the rate did not differ in the 20-30ºC temperature range. The threshold temperature (TT) was 7.2ºC, and 188.7 degrees-day were required for the development (egg-to-adult period). The parasitism rate and longevity were higher at 50 and 70% of RH. This shows that temperature and RH may affect the parasitism capacity of T. radiata on nymphs of D. citri, which can explain the great parasitism variation for D. citri observed in citrus groves in São Paulo State, Brazil.