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Chocolate is an adequate matrix to deliver bioactive ingredients. However, it contains high sugar levels, one of the leading causes of chronic degenerative diseases. This work aimed to evaluate the effects of milk chocolate reformulation with alternative sugar sweeteners (Sw; isomalt + stevia), probiotics (Prob), and ω-3 polyunsaturated fatty acids (PUFAs) on its physicochemical properties and consumers' acceptability. Lactobacillus plantarum 299v (L. p299v) and Lactobacillus acidophilus La3 (DSMZ 17742) were added as Prob strains, and fish oil (FO) was added as the source of ω-3 PUFAs. Prob addition resulted in chocolates with >2 × 107 colony forming unit (CFU) per serving size (12 g). Except for Prob, aw values of all treatments were <0.46. Sw and Sw + Prob presented the nearest values to the control in hardness, whereas Sw without FO increased fracturability. FO, Sw + FO, and Sw + Prob + FO contained 107.4 ± 12.84, 142.9 ± 17.9, and 133.78 ± 8.76 mg of ω-3 PUFAs per chocolate, respectively. Prob + FO increased the resistance of chocolate to shear stress, while Sw + FO showed a similar flow behavior to the control. The consumers' acceptability of Sw + Prob chocolate was adequate, while Sw + Prob + FO had higher acceptability than Prob + FO. Health benefits of reformulated milk chocolates requires further assessment by in vitro, in vivo and clinical studies.

RESUMO

In this study, a milk chocolate formulation was developed to serve as vehicle of Omega-3 (ω3) polyunsaturated fatty acids (PUFAs) and probiotics (L. plantarum 299v and L. rhamnosus GG). Fish oil (FO) was incorporated in chocolate as a source of ω3 PUFAs. Probiotics (Prob) and FO were added during tempering, obtaining chocolates with 76.0 ± 5.2 mg (FO1) or 195.8 ± 6.5 mg (FO2) of ω3 PUFAs, and >1 × 106 CFU of Prob per chocolate portion (12 g). The physicochemical properties (rheological analysis, texture, surface instrumental color, aw, and fatty acid profile), and sensory acceptability of the formulations were determined. Prob and FO generated a decrease in L* and white index (WI) values. Except for Prob + FO2, all treatments showed a decrease in aw. Rheological parameters of FO1 and Prob + FO1 presented the most similar behavior as compared with the control. Prob or FO1 addition did not affect the overall consumer's acceptability of chocolate; and when both nutraceuticals were combined (Prob + FO1) the product showed adequate overall acceptability. FO2 formulations were not considered adequate to maintain physicochemical properties and sensory acceptability of chocolate. Results indicated that milk chocolate is a suitable vehicle for delivering ω3 PUFAs and Prob, which are essential to enhance cognitive development in children.

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Pseudapanteles dignus (Muesebeck; Hymenoptera: Braconidae) is an American endoparasitoid that attacks the South American tomato leafminer Tuta absoluta (Meyrick; Lepidoptera: Gelechiidae). The interaction between P. dignus and T. absoluta in tomato (Solanum lycopersicum L.; Solanales: Solanaceae) crops has demonstrated that this enemy exhibits some desirable ecological traits as an effective biological control agent of this pest. With the aim of extending the use of P. dignus to other solanaceous crops, laboratory experiments were carried out to assess some life history traits and the parasitism efficiency when parasitizing T. absoluta larvae fed on eggplant (Solanum melongena L.; Solanales: Solanaceae). Rearings and experiments were conducted at 25 ± 2°C, ≈70% RH, and 14:10 (L:D) h photoperiod, and T. absoluta was fed with eggplant. P. dignus developmental times of immature stages were lower (~ 5 d) on S. melongena than on S. lycopersicum. The female did not exhibit a pre-reproductive period, and its oviposition period lasted longer (~ 4 d) than that determined in tomato plants. Adult longevity was ca. 24 d for both sexes. Females produced ca. 61 cocoons during their lives and the maximum daily percentage of parasitism was 50% at the first day of adult emergence. Functional response of P. dignus on eggplant was density-independent of the host density offered, as in tomato plant, and the instantaneous attack rate (a') was 0.24 attacked larvae/ available larvae, in 24 h. Our results indicate that although there are differences, P. dignus would have a similar performance in eggplant and tomato in terms of its efficacy in the control of T. absoluta.

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Wild vegetation surrounding crops may provide temporary habitat and potential food sources for phytoseiids in different seasons. Monthly vegetation samples of wild plants adjacent to strawberry plants and wild plants in a vegetation strip close to the crop were taken. The frequency of Neoseiulus californicus, Tetranychus urticae and other mites and insects was recorded. In addition, in a laboratory assay, the survival, developmental time and fecundity of females fed on pollen of strawberry and pollen of wild plants where N. californicus was recorded during their flowering, were estimated. Pollen from Urtica urens, Lamium amplexicaule, Convolvulus arvensis, Sonchus oleraceous, Galega officinalis, and Fragaria x ananassa (strawberry) allowed development of N. californicus to adult, but not reproduction. Survival was 70-80 % when fed on pollen from S. oleraceus, G. officinalis and C. arvensis, 80-90 % when fed on pollen from U. urens and F. x ananassa, and more than 90 % when fed on T. urticae and on pollen from L. amplexicaule. In autumn and winter, U. urens, L. amplexicaule and S. oleraceous could promote the persistence of N. californicus when prey density in strawberry is low, offering T. urticae, thrips and pollen. In summer, pollen of C. arvensis and G. officinalis would contribute to the persistence of N. californicus when the strawberry crop is ending and offers scarce food resources. Although the pollen of these plants would not enable the predator population to increase, the presence of these plants in the vicinity of strawberry could contribute to the persistence of N. californicus population and help to limit T. urticae growth when this pest begins to colonize the crop.

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The tomato moth, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a key pest of tomato, Lycopersicon esculentum L., crops in Central and South America. At present it is dispersing rapidly in Africa and Eurasian continents as an invasive pest, threatening worldwide tomato production. Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae) is an American endoparasitoid reported as the main natural enemy of T. absoluta in commercial tomato. To gain knowledge of the potential role of P. dignus in the biological control of this pest, we determined its population parameters in laboratory and the parasitoid's impact on T. absoluta in the field. In laboratory, lifetime fecundity was 193 eggs per female, and longevity was 24 and 26 d for female and male, respectively. The finite rate of increase (λ) was 1.15 per female per day and the intrinsic rate of natural increase (r(m)) was 0.14. The net reproductive rate (R(0)) was found to be 51.2, and generation time (T) 28.8 d. The time for doubling the population (DT) was 5 d. Furthermore, field parasitism of T. absoluta varied between 33 and 64% in the different years studied. Population parameters estimated in this study can be considered baseline information for a mass-rearing protocol of this parasitoid. Moreover, growth rates of P. dignus, particularly r(m), and its impact on field populations of T. absoluta indicated that this parasitoid is a valuable candidate for biological control of this pest.

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Soybean pest control in Argentina is done just by chemical control using broad-spectrum pesticides. Alpaida veniliae (Araneae, Araneidae) is one of the most abundant spider species of the orb web weaver guild in soybean, and it is considered a very important polyphagous predator, attacking different insects' families. The objective of this study was to determine if neurotoxic insecticides commonly used in soybean crops and a new active ingredient registered in Argentina (spinosad) adversely affected survival, prey consumption, mating behaviour, web building and reproductive capacity of A. veniliae females, under standard laboratory conditions. Spinosad was the most harmful insecticide due to high acute toxicity, even at lower concentrations than those registered for its field use and for its sublethal effects also. Cypermethrin caused several sublethal effects although its acute toxicity on spider was lower than other insecticides. It reduced prey consumption, affected web building, caused abnormalities in eggs sacs and decreased drastically the fecundity and fertility at sublethal concentrations. Endosulfan did not reduce prey consumption but it affected web building, caused abnormalities in eggs sacs and egg masses, and decreased the fecundity and fertility. Spinosad was also the compound with the most drastic effect on web building, it did not reduce prey consumption and fecundity, but fertility was reduced and abnormalities in egg sacs and egg masses were observed. The use of these insecticides in IPM programs according to their potential toxicity on spider communities is discussed.

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Studies in transgenic soybean crops in Buenos Aires province, Argentina, revealed that Alpaida veniliae is one of the most abundant species in the guild of orb web spiders. This species is an effective natural enemy of insect pests affecting this crop. In the present study we carried out a descriptive and quantitative analysis of sexual behavior (courtship, mating and post-mating) of A. veniliae. The spiders were collected in transgenic soybean crops located in Chivilcoy (35 degrees 01' S - 60 degrees 06' W), Buenos Aires, Argentina, and reared under laboratory conditions. Based on observations of 20 couples (with virgin females), behavioral units of male and female in terms of postures and movements, including details on duration and frequency, were described at all stages of sexual activity (courtship, mating and post-mating). Courtship exhibited the greatest number and duration of behavioral units in both sexes. Male and female had a sequence of 16 and nine units, respectively, being the frequency of repetitions of the units significantly higher in the male. Mating was brief and males used a single palp to fill only one of the female spermathecae, after which the female became unreceptive. Mating had two behavioral units in the male and only one in the female. During post-mating males had three and females two behavioral units. The average duration of the whole sexual behavior was 541.90 +/- 123.1 seconds for the male and 338.20 +/- 74.1 seconds for the female. Alpaida veniliae females rarely accept a second mating with the same or another male (remating), indicating a strict monogamy. In 46% of observed mating, the female cannibalized the male after it. Females became unattractive after mating, since stop producing sex pheromones, causing a reduction of the male vibratory courtship. The high cost of courtship, including the risk of cannibalism, would reinforce the selectivity of males towards receptive virgin females.

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Studies in transgenic soybean crops in Buenos Aires province, Argentina, revealed that Alpaida veniliae is one of the most abundant species in the guild of orb web spiders. This species is an effective natural enemy of insect pests affecting this crop. In the present study we carried out a descriptive and quantitative analysis of sexual behavior (courtship, mating and post-mating) of A. veniliae. The spiders were collected in transgenic soybean crops located in Chivilcoy (35º01’ S - 60º06’ W), Buenos Aires, Argentina, and reared under laboratory conditions. Based on observations of 20 couples (with virgin females), behavioral units of male and female in terms of postures and movements, including details on duration and frequency, were described at all stages of sexual activity (courtship, mating and post-mating). Courtship exhibited the greatest number and duration of behavioral units in both sexes. Male and female had a sequence of 16 and nine units, respectively, being the frequency of repetitions of the units significantly higher in the male. Mating was brief and males used a single palp to fill only one of the female spermathecae, after which the female became unreceptive. Mating had two behavioral units in the male and only one in the female. During post-mating males had three and females two behavioral units. The average duration of the whole sexual behavior was 541.90±123.1 seconds for the male and 338.20±74.1 seconds for the female. Alpaida veniliae females rarely accept a second mating with the same or another male (remating), indicating a strict monogamy. In 46% of observed mating, the female cannibalized the male after it. Females became unattractive after mating, since stop producing sex pheromones, causing a reduction of the male vibratory courtship. The high cost of courtship, including the risk of cannibalism, would reinforce the selectivity of males towards receptive virgin females.

Estudios realizados en cultivos de soja transgénica en la provincia de Buenos Aires, Argentina, revelaron que Alpaida veniliae es una de las especies más abundantes dentro del gremio de arañas orbiculares. Esta especie es un eficaz enemigo natural de las plagas de insectos de este cultivo. En el presente estudio se llevó a cabo un análisis descriptivo y cuantitativo de la conducta sexual (cortejo, cópula y post-cópula) de A. veniliae. Las arañas fueron recolectadas en cultivos de soja transgénica ubicados en Chivilcoy (35º01’ S - 60º06’ W), (Buenos Aires, Argentina) y criadas en condiciones de laboratorio. A partir de la formación de 20 parejas (con hembras vírgenes), se observaron las unidades de comportamiento de machos y hembras, en términos de posturas y movimientos, incluyendo los detalles de su duración y frecuencia en todas las etapas del apareamiento. El cortejo exhibió el mayor número y la mayor duración de las unidades de comportamiento en ambos sexos. La secuencia de unidades fue 16 en el macho y nueve en la hembra, siendo la frecuencia de repeticiones de las unidades significativamente mayor en el macho. La cópula fue breve y el macho usó un solo palpo transfiriendo esperma a una sola espermateca de la hembra. Hubo dos unidades de comportamiento en el macho y una en la hembra. Durante la post-cópula el macho tuvo tres y la hembra dos unidades de comportamiento. La duración media de todo el comportamiento sexual fue 541.90±123.1 segundos para el macho y 338.20±74.1 segundos para la hembra. La hembra de A. veniliae sólo excepcionalmente aceptó una segunda cópula con el mismo u otro macho, lo que indica una monogamia estricta. En el 46% de las cópulas observadas la hembra canibalizó al macho al terminar la misma. Debido a que a partir de este momento dejan de producir feromonas sexuales, se vuelven no receptivas y provocan una reducción del cortejo del macho. El alto costo del cortejo del macho, incluyendo el riesgo de canibalismo, reforzaría la selectividad de éstos hacia las hembras receptivas vírgenes.

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We examined the interaction between the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), a key pest of tomato crops in South America, and its main solitary larval parasitoid, Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae). The pattern of parasitism of T. absoluta by the parasitoid was studied at three scales on tomato crops: plant, leaf, and leaflet. Host density, spatial distributions of both host and parasitoid, percentages of parasitism, variation in the probability and risk of parasitism in relation to host density, and the spatial density dependence were assessed in a horticultural region in Argentina. The spatial distribution of T. absoluta was clumped at all sites and scales, whereas that of P. dignus was much more variable, fitting to negative, positive binomial distributions and to Poisson series. Percentages of parasitism were as follows: site 1, 17.06%; site 2, 27.53%; site 3, 26.47%; site 4, 45.95%. Parasitoid aggregation in relation to host density was found at leaf and leaflet scales. However, the proportion of parasitized hosts was independent of host density. The variability of parasitism rates exhibited at the three spatial scales seems to result in partial refuges for the host, which might contribute to the persistence of the interaction between host and parasitoid. We discuss our field observations in relation to ecological theory and its potential application to the biological control of T. absoluta on tomato.

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Laboratory studies were conducted to measure selected life history traits and the functional response of the parasitoid Pseudapanteles dignus (Muesebeck), a major enemy of Tuta absoluta (Meyrick) in tomato crops in South America. Newly mated P. dignus females were individually exposed to 10 host larvae in mines for 24 h. We determined developmental time from egg to pupal formation and pupal stage duration, female adult life span, fecundity, reproductive period, daily parasitism rate, and sex ratio of offspring. For the functional response experiment, treatments consisted of six host densities: 3, 5, 7, 10, 15, 20, or 30 larvae. The number and proportion of parasitized hosts were calculated for each density. The shape of the functional response curve was analyzed by logistic regression. P. dignus females attacked hosts daily, exhibiting modest lifetime fecundity (approximately 32 parasitized hosts per female) and a female-biased offspring sex ratio. Female adult life span was 36 d. P. dignus showed a type I functional response within the range of host densities tested. We observed that females detect and parasitize the host within a wide range of densities, including low densities. The functional response curve reached an asymptote at a mean density of six hosts per day and seemed not to be egg-limited. Percent parasitism was approximately 30%. The ecological implications of the results in relation to the potential of P. dignus for the biological control of T. absoluta in tomato are discussed.

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Tuta absoluta (Meyrick) is an important tomato pest that also feeds on other host-plants from the Solanceae family. We studied the effect of two cultivated plants, tomato (Lycopersicum esculentum Mill.) and potato Solanum tuberosum L. on the development and populational parameters of T. absoluta related with host-plant suitability. Larval developmental time, pupal weight, mean fecundity and an index of host-plant quality (IPQ = pupal weight / frass weight) were estimated. Age-specific survivorship and fecundity life tables were constructed in the laboratory to evaluate the following populational parameters: net reproductive rate (Ro), intrinsic rate of increase (r) and generation time (T). Larval developmental time was shorter and pupal weight was higher (P < 0.0001) for larvae reared on tomato (P < 0.0001). Mean fecundity was not significantly different on both plants (P = 0.07) and food quality of host-plant was higher for tomato (P = 0.02). Mean population parameters on tomato were: Ro = 48.92; T = 27.98, r = 0.14; and on potato: Ro = 14.43; T = 32.35, r = 0.08. Although results showed that tomato was a more suitable host-plant and had a better nutritional quality than potato, when T. absoluta fed on potato the potential population increase requires attention. Under appropriate climatic conditions, spatial and temporal coincidence between crop and pest, T. absoluta could become a pest for the potato crop.

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Tuta absoluta (Meyrick) is an important tomato pest that also feeds on other host-plants from the Solanceae family. We studied the effect of two cultivated plants, tomato (Lycopersicum esculentum Mill.) and potato Solanum tuberosum L. on the development and populational parameters of T. absoluta related with host-plant suitability. Larval developmental time, pupal weight, mean fecundity and an index of host-plant quality (IPQ = pupal weight / frass weight) were estimated. Age-specific survivorship and fecundity life tables were constructed in the laboratory to evaluate the following populational parameters: net reproductive rate (Ro), intrinsic rate of increase (r) and generation time (T). Larval developmental time was shorter and pupal weight was higher (P < 0.0001) for larvae reared on tomato (P < 0.0001). Mean fecundity was not significantly different on both plants (P = 0.07) and food quality of host-plant was higher for tomato (P = 0.02). Mean population parameters on tomato were: Ro = 48.92; T = 27.98, r = 0.14; and on potato: Ro = 14.43; T = 32.35, r = 0.08. Although results showed that tomato was a more suitable host-plant and had a better nutritional quality than potato, when T. absoluta fed on potato the potential population increase requires attention. Under appropriate climatic conditions, spatial and temporal coincidence between crop and pest, T. absoluta could become a pest for the potato crop.

Tuta absoluta (Meyrick) es una importante plaga del tomate que puede utilizar también otras solanáceas como plantas huéspedes. Este trabajo evaluó el efecto del tomate, Lycopersicum esculentum Mill. y la papa, Solanum tuberosum L., sobre algunos aspectos del desarrollo y parámetros poblacionales relacionados con la calidad del alimento. Se midieron: duración del estado larval, peso pupal, fecundidad y un índice de la calidad alimentaria de la planta huésped (peso pupal / peso de heces). Por medio de tablas de vida en el laboratorio se obtuvieron datos de supervivencia y fecundidad específicas por edad con los cuales se calcularon: tasa reproductiva neta (Ro), tasa intrínseca de crecimiento (r) y tiempo generacional (T). Los individuos alimentados con tomate tuvieron una menor duración del estado larval (P < 0,0001), y un mayor peso pupal (P < 0,0001) que con papa. La fecundidad promedio fue marginalmente más alta en tomate (P = 0,07) mientras que la calidad nutricional fue mayor para el tomate (P = 0,025). Los parámetros poblacionales promedio fueron: Ro = 48,92; T = 27,98, r = 0,14, en tomate; y Ro = 14,43; T = 32,35, r = 0,08 en papa. Si bien los resultados indicaron que el tomate exhibió una mayor calidad nutricional que la papa, las cohortes de T. absoluta alimentadas con este huésped secundario, mostraron un crecimiento relativamente importante. Bajo condiciones climáticas favorables y una coincidencia espacial y temporal entre la polilla y el cultivo de papa, sus poblaciones podrían convertirse en una plaga para el mismo.

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Neoseiulus californicus (McGregor) is a promising agent for successful Tetranychus urticae Koch control through conservation techniques, in strawberry crops in La Plata (Buenos Aires, Argentina). In prey-predator interaction, initial relative densities have an important effect on system dynamics. The economic threshold level (ETL) used for this pest in the present study was 50 active mites per leaflet. In our laboratory experiments, initial T. urticae to N. californicus ratio had a significant effect on the population abundance of T. urticae at a 7-day period. When pest/predator ratio was 5/1 (at initial pest densities from 5 to 15 females/leaflet) the final number of active T. urticae/leaflet was significantly lower than the ETL, while at 20 females/leaflet this number did not differ from the ETL. At 7.5/1 ratio, the final number of active T. urticae/leaflet, at initial pest densities from 5 to 15 females/leaflet, reached the ETL without surpassing it. At 10/1 and 15/1 ratios, pest densities exceeded the ETL only at 15 initial T. urticae/leaflet. Most greenhouse and field observations were consistent with the predictions of a graphical model based on experimental results. This predator was very effective in limiting pest densities at a 7-day period and within the range of pest-predator ratios and absolute densities used in this study. Conservation of N. californicus promoting favorable pest/predator ratios may result in early control of T. urticae.

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