Associative learning in wild Anastrepha obliqua females (Diptera, Tephritidae) related to a protein source

Abstract

ABSTRACT. The aim of the present study was to determine whether wild adult Anastrepha obliqua (Macquart, 1835) females are able to associate a compound (quinine sulphate -QS) not related to their habitual diet with a protein-enriched food. Females were first fed on diets based on brewer yeast and sucrose containing or not QS. The groups were then allowed to choose between their original diets and a diet with or without QS, depending on the previous treatment, and between a diet based on agar and a diet containing agar and QS. When the nutritional value of the diets was adequate, the females did not show any preference for the diet with or without QS. With respect to the agar diet and the agar + QS diet, females previously fed on a nutritive diet containing QS preferred the diet containing QS, indicating an association between the compound and the nutritional value of the diet. The importance of this behavioral strategy is discussed. KEYWORDS.Associative learning, fruit flies, Anastrepha obliqua, protein, feeding behavior.Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. dos Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brasil. RESUMO. Aprendizagem associativa em fêmeas selvagens deAnastrepha obliqua (Diptera, Tephritidae) em relação a uma fonte protéica. O objetivo do presente estudo foi determinar se fêmeas adultas selvagens de Anastrepha obliqua (Macquart, 1835) são capazes de associar um composto (sulfato de quinino-SQ) não-relacionado à sua dieta habitual com um alimento rico em proteínas. Primeiro, as fêmeas foram alimentadas com dietas à base de lêvedo de cerveja e sacarose contendo ou não SQ. Os grupos foram então colocados para escolher entre sua dieta original e dietas com ou sem SQ, dependendo do tratamento prévio, e entre uma dieta à base de agar somente e outra à base de agar e SQ. Quando o valor nutricional das dietas era adequado, as fêmeas não mostraram nenhuma preferência para a dieta com ou sem SQ. Em relação às dietas de agar e agar+SQ, fêmeas previamente alimentadas com uma dieta nutritiva contendo SQ preferiram a dieta contendo SQ, indicando uma associação entre o composto e o valor nutricional da dieta. A importância desta estratégia comportamental é discutida.

Oviposition behavior in wild Anastrepha obliqua (Macquart, 1835) (Diptera: Tephritidae): Initial study of associative learning related to a protein source.

“…The stimulating effect of novelty, in this context, would also explain the significant difference that was found on the first day of selection, once this was the first day that females had contact with the Y substrate. The results found in this present study differ from the ones found in the study by Cresoni-Pereira and Zucoloto (2006), where associative learning related to A. obliqua feeding behavior was studied. When the diets for choice had an adequate nutritional value, the flies did not show any preference for the diet with yeast + quinine sulphate or the diet containing only yeast.…”

“…The five-day period of experience was based on previous studies about associative learning related to the A. obliqua feeding behavior (Cresoni-Pereira & Zucoloto, 2006).…”

“…CresoniPereira and Zucoloto (2006) supposed that, as the flies have fed on two blocks of diets (brewer's yeast + quinine sulphate and brewer's yeast), the dilution of quinine sulphate may have enabled the minimization of any effect resulting from the presence of this compound in the insect body. This strategy is not possible during oviposition behavior, so the effect of quinine sulphate was present as previously discussed.…”

“…Crisci and Zucoloto (2001) hypothesized that Zucoloto, 2006). In this context, one explanation would be that the quinine sulphate is deterrent for the oviposition behavior of A. obliqua, as it was for the feeding behavior; so the negative stimulus resulting from this compound would have prevented the association.…”

“…This compound was used in previous studies of associative learning with the same species (Cresoni-Pereira & Zucoloto, 2006). Since the use of allelochemicals as a sign of nutrient-specific presence in hosts is common among insects, our hypothesis is that females would associate QS with the presence of a protein source.…”