Aprendizagem associativa em fêmeas e machos de Anastrepha obliqua (Diptera, Tephritidae) com diferentes idades e estados nutricionais / Associative learning in anastrepha obliqua (diptera, tephritidae) wild females and males of different ages and nutritional states

Adult Anastrepha obliqua fruit-flies need protein sources to promote sexual maturation and egg production. Learning can be a mechanism to improve the foraging behavior to acquire this nutrient. Learning could be defined as the acquisition of a new representation of neuronal information, and it can only be indirectly observed through its potential effect on behavior. In the present study, the occurrence or not of associative learning in A. obliqua females and males of different ages and nutritional states concerning sucrose (carbohydrate) and brewer´s yeast (protein source) was observed. Associative learning for sucrose was demonstrated in young and old females and males only when deprived of food for 2 days after the experience period. As concerns yeast, the associative learning was demonstrated in deprived young and old females only.

Adultos de moscas-das-frutas, Anastrepha obliqua, necessitam de fontes proteicas para promover a maturação sexual e produção de ovos. A aprendizagem pode ser um mecanismo para melhorar o comportamento de forrageamento na aquisição deste nutriente. Dentre as diferentes definições de aprendizagem uma delas a define como a aquisição de uma nova representação de informação neuronal e pode ser indiretamente observada através de seu efeito potencial no comportamento. No presente estudo, a ocorrência ou não de aprendizagem em fêmeas e machos de A. obliqua de diferentes idades e estados nutricionais foram observadas em relação à sacarose (carboidrato) e lêvedo de cerveja (fonte de proteína). A aprendizagem associativa para sacarose foi demonstrada em fêmeas e machos jovens e velhos somente quando privados de alimento por dois dias depois do período de experiência. Em relação ao lêvedo, a aprendizagem associativa foi demonstrada em fêmeas jovens e velhas, mas não nos machos.

Evolution of the human feeding behavior

The main objective of this review is to discuss human feeding behavior based on evolution. With regard to feeding, the human species has undergone various changes during its evolutionary and social history, from the hunting and gathering phase, including the discovery of fire, to modern times, mainly after the implementation of agriculture. These changes exerted a direct influence on feeding habits and behavior and a considerable impact on some aspects of human health. The present review also discusses some of the foods consumed by the human species that are controversial among investigators from an evolutionary perspective.

Influence of male nutritional conditions on the performance and alimentary selection of wild females of Anastrepha obliqua (Macquart)(Diptera, Tephritidae)

Influence of male nutritional conditions on the performance and alimentary selection of wild females of Anastrepha obliqua (Macquart) (Diptera, Tephritidae). The behavior of A. obliqua females is regulated by endogenous and exogenous factors and among these the presence of males. Experiments were carried out to investigate whether the presence of males and their nutritional condition may affect the behavior of self-selection feeding and the performance of A. obliqua females. Females were sorted in groups containing yeast-deprived females and males, and non-yeast-deprived females and males. The females were maintained apart from the males by a transparent plastic screen. Several yeast and sucrose combinations were offered to the females in a single diet block or in separate blocks. Ingestion, egg production, longevity and diet efficiency were determined. The non-yeast-deprived males positively influenced the females performance when the latter were fed with yeast and sucrose in distinct diet blocks. Performance was better in the groups without males and with yeast-deprived males where the females could not select the nutrient proportions (yeast and sucrose in a single diet block).

Influência do estado nutricional do macho na performance e seleção alimentar de fêmeas selvagens de Anastrepha obliqua (Macquart) (Diptera, Tephritidae). O comportamento das fêmeas de Anastrepha obliqua é regulado por fatores endógenos e exógenos, e entre estes últimos pode estar a presença do macho. Experimentos foram realizados para investigar se a presença do macho e seu estado nutricional alteram o comportamento de auto-seleção alimentar e a performance das fêmeas de A. obliqua. Grupos com fêmeas, fêmeas e machos privados de lêvedo e fêmeas e machos não privados de lêvedo foram montados, permanecendo as fêmeas separadas dos machos por uma divisória plástica transparente. Várias combinações de lêvedo e sacarose foram oferecidas em um único bloco de dieta ou em blocos separados para as fêmeas. Ingestão, produção de óvulos, longevidade e eficiência das dietas foram medidas. Os machos não privados de lêvedo influenciaram positivamente a performance das fêmeas quando estas foram alimentadas com lêvedo e sacarose em blocos distintos de dieta. Nos grupos em que as fêmeas não puderam selecionar as proporções de nutrientes (lêvedo e sacarose em um único bloco de dieta), a performance foi melhor para os grupos sem machos e com machos privados de lêvedo.

Oviposition behavior and performance aspects of Ascia monuste (Godart, 1919) (Lepidoptera, Pieridae) on kale (Brassica oleracea var. acephala)

Host part selection by ovipositing females of Ascia monuste (Godart, 1919) (Lepidoptera, Pieridae) on kale (Brassica oleracea var. acephala) was determined in greenhouse and field. Performance of offspring (larval period, efficiency of food utilization, number of eggs/female and others) was investigated under laboratory conditions. In the field, the number of A. monuste egg clutches on the apical and medium parts of kale leaves was greater than on the basal part. In greenhouse, A. monuste exhibited a strong preference for the apical part of kale leaves for ovipositing. The best results on food utilization indices, pupal mass and female wing size were obtained with the leaf apical part. This part of kale leaves exhibited the highest nitrogen and protein concentration and the smallest water content, when compared to the other leaf parts. However, the apical part of the leaves seems not to provide ovipositing females with enough protection against birds, making them easy preys in the field. We suggest that good relationship between oviposition preference and performance of offspring was hindered by predation in field conditions