Fruit flies of the genus Anastrepha Schiner, 1868 are well-known for having economical importance since they damage commercially cultivated fruits. Nutritional demands during the immature and adult stages are different, so the larvae do not develop well using the same diet as the adults. Although the insect basic nutritional needs are well-known, there is also the challenge to elaborate rearing diets adequate to species with specific needs. The aim of this study was to determine the effect on the Anastrepha obliqua (Macquart, 1835) larvae performance of different kinds and amounts of carbohydrates in the diet. Larvae were individually reared until pupation in test tubes containing one of the artificial diets to be tested. The basic composition of the diets to be tested included 2.5 g agar, 3.25 g brewer's yeast and several different amounts of flour and sucrose. The suitability of the artificial diet for A. obliqua was tested evaluating the larvae and pupae survival (%) and the larvae, pupae and larvae-adults periods of development. The diet containing flour (2 g) and sucrose (2 g) and the diet containing only sucrose (5.5 g) have shown the best results regarding larval performance. All tested diets presented similar or superior results as compared to diets used in other studies. The importance of flour and its nutritional value for the larvae was discussed.

Moscas das frutas do gênero Anastrepha Schiner, 1868 são conhecidas por sua importância econômica devido aos danos que elas causam nos frutos comerciais. As exigências nutricionais dos estágios imaturo e adulto são diferentes e as larvas não se desenvolvem bem utilizando a mesma dieta do adulto. Embora as necessidades nutricionais básicas dos insetos sejam bem conhecidas, existe ainda o problema de elaborar dietas de criação adequadas para espécies com necessidades específicas. O objetivo deste trabalho foi verificar o efeito de diferentes tipos e quantidades de carboidratos na dieta sobre a performance larval de Anastrepha obliqua (Macquart, 1835). Larvas foram criadas individualmente em tubos de ensaio contendo uma das dietas artificiais a serem testadas onde elas foram mantidas até a pupação. A composição básica das dietas testadas incluia 2,5 g de agar, 3,25 g de levedo de cerveja e quantidades variadas de sacarose e farinha de trigo. A adequação do meio artificial para A. obliqua foi testada pela avaliação da sobrevivência larval e pupal (%) e o tempo de desenvolvimento larval, pupal e de larva-adulto. A dieta contendo farinha de trigo (2 g) e sacarose (2 g) e a dieta somente com sacarose (5,5 g) foram as que apresentaram melhor performance larval. Todas as dietas testadas apresentaram resultados similares ou superiores às dietas utilizadas em outros trabalhos. A importância da presença da farinha de trigo e seu valor nutricional para as larvas são discutidos.

In associative learning, experience enables an animal to associate a conditioned stimulus with some other meaningful stimulus producing either positive or negative effects. In this way, on a subsequent encounter, the response that was previously elicited only by the meaningful stimulus is then elicited by the conditioned stimulus as well. The aim of the present study was to investigate whether wild Anastrepha obliqua (Macquart, 1835) females are able to associate the presence of quinine sulphate (QS) in the composition of oviposition substrates with the presence of brewer's yeast (a protein source). First, the females were submitted to an experience period with artificial substrate containing brewer's yeast + QS (YQS substrate). After this period, the females were allowed to choose between substrates with or without QS. In one group, the substrates contained brewer's yeast (YQS x Y substrates); in the other group, the substrates contained only agar (AQS x A substrates). In the YQS x Y choice situation, a smaller quantity of eggs was found on YQS substrates, only on the first choice day. In the AQS x A choice situation, there was no preference for one of the substrates on each of the three choice days. However, we think it is too early to state that A. obliqua females are not able to perform the association in question. These flies show a high behavioral flexibility concerning their oviposition behavior strategies. Besides, this behavior, in this species, includes several stages. Based on it, possible explanations for the results are discussed in this study.

Vários fatores podem atuar durante a seleção de substratos para oviposição por insetos. O presente estudo teve por objetivo responder às seguintes questões relacionadas ao comportamento de oviposição de Anastrepha obliqua. O carboidrato presente na dieta do adulto (glicose ou sacarose) pode influenciar a preferência da fêmea por um substrato para oviposição com composição semelhante? A experiência prévia com um hospedeiro que possui um dos dois carboidratos citados pode interferir em escolhas futuras entre substratos para oviposição? Os resultados indicaram que o tipo de carboidrato presente na dieta do adulto não exerceu influência sobre a preferência das fêmeas por um substrato artificial para oviposição, tanto quando em combinação com lêvedo de cerveja ou quando sozinho. O efeito da experiência no comportamento de oviposição foi notado quando o contato prévio foi com substratos artificiais para oviposição contendo lêvedo e sacarose. Os resultados são discutidos com base na plasticidade comportamental apresentada pela espécie com relação ao comportamento alimentar e de oviposição.

Several factors influence the selection of oviposition substrates by insects. The aim of the present work was to find answers to the following questions related to the oviposition behavior of Anastrepha obliqua. Can carbohydrates (glucose or sucrose) present in the adult diet have influence on the female preference for an oviposition substrate with similar composition? Can the previous experience with a host containing one of mentioned carbohydrates interfere in further selection of oviposition substrates? The results showed that the kind of carbohydrate present in the adult diet did not affect the female preference for an artificial oviposition substrate, neither when it was presented by itself nor in combination with brewer's yeast. The effect of experience in the oviposition behavior was observed when there was a previous contact with artificial oviposition substrates containing yeast and sucrose. The data are discussed in terms of the behavioral plasticity presented by this species in relation to feeding and oviposition behaviors.