Autophagy in Drosophila ovaries is induced by starvation and is required for oogenesis.

Autophagy, an evolutionarily conserved lysosome-mediated degradation, promotes cell survival under starvation and is controlled by insulin/target of rapamycin (TOR) signaling. In Drosophila, nutrient depletion induces autophagy in the fat body. Interestingly, nutrient availability and insulin/TOR signaling also influence the size and structure of Drosophila ovaries, however, the role of nutrient signaling and autophagy during this process remains to be elucidated. Here, we show that starvation induces autophagy in germline cells (GCs) and in follicle cells (FCs) in Drosophila ovaries. This process is mediated by the ATG machinery and involves the upregulation of Atg genes. We further demonstrate that insulin/TOR signaling controls autophagy in FCs and GCs. The analysis of chimeric females reveals that autophagy in FCs, but not in GCs, is required for egg development. Strikingly, when animals lack Atg gene function in both cell types, ovaries develop normally, suggesting that the incompatibility between autophagy-competent GCs and autophagy-deficient FCs leads to defective egg development. As egg morphogenesis depends on a tightly linked signaling between FCs and GCs, we propose a model in which autophagy is required for the communication between these two cell types. Our data establish an important function for autophagy during oogenesis and contributes to the understanding of the role of autophagy in animal development.

Components of reward in social dilemmas.

A social dilemma (Dawes, 1980) may be defined as a situation in which a collection of individuals is faced with a conflict between maximizing selfish interests and maximizing collective interests. The dilemma is based on the fact that if all choose to maximize selfish interests, all are worse off than if all choose to maximize collective interests. In a decomposed social dilemma (Pruitt, 1967), the outcomes are divided into two components: one component is based on one's own choice and the second component is based on the choices made by the others. Using 3-person decomposed games, two types of incentives were contrasted: a positive incentive (bonus) for cooperative choices and a negative incentive (penalty) for noncooperative choices. Two experiments were conducted using male college students. The results of both experiments showed that the positive incentive evoked a higher level of cooperation than the negative incentive. The results are discussed in terms of nonadditive utility components, Pruitt's motivational interpretation, and Kelley and Thibaut's (1978) theory of interdependence.