Why only female mosquitoes bite? The adult female mosquito has to bear a reproductive process energetically very costly, where they must quickly produce large numbers of eggs. Therefore, she does not initiate physiological and endocrine processes that lead to reproduction until she had made a blood meal. This type of reproductive strategy called anautogeny is not exclusive of mosquitoes but is found in other insects. For example, the cockroach Blattella germanica also needs to eat to trigger endocrine mechanisms that produce the onset of the breeding cycle. Thus, in anautogenous organisms there must exist nutritional signals to inform the different organs involved in reproduction that a meal has occurred. Two of the pathways that contribute to the nutritional signal transmission, both in insects and other organisms, are the insulin receptor/phosphatidylinositol-3-kinase (InR/PI3K) and “target of rapamycin” (TOR) pathways. These pathways are involved in detecting nutritional signals and activating different processes, such as growth, cell proliferation, longevity and cancer. Our group works in a research line for studying these pathways in the cockroach B. germanica and their relationships to the activation of vitellogenesis and reproduction. This cockroach is a very good model of reproductive physiology in insects because their reproduction is governed, as it occurs in most insects, by juvenile hormone, and not by ecdysteroids as it only happens in dipterans (flies and mosquitoes). We are conducting studies using different experimental models, including fed and fasted individuals and specimens in which we have manipulated the expression levels of different proteins of the nutritional signaling pathways, such as InR itself, TOR, the kinase of the ribosomal protein S6 (S6K) and the FOXO transcription factor, among others. Recent findings indicate that both InR/PI3K and TOR pathways are involved in activating the production of juvenile hormone in the corpora allata and vitellogenic protein synthesis in the fat body (Maestro et al. (2009) J. Biol. Chem. 284, 5506-5513) and Abrisqueta and Maestro, in preparation).