Long-term effects of diet on the neuroendocrine system of the sheep blowfly, Lucilia sericata

ABSTRACT. The medial neurosecretory cells (MNC), corpus allatum (CA) and ovaries of Lucilia sericata Mg. are quiescent in mature flies fed on a diet of sugar and water, but these tissues rapidly respond to the ingestion of a protein meal. The present study revealed that after oogenesis, virgin flies synthesized and stored neurosecretory material, but this activity declined as they grew older. At the same time, the CA, following a decrease in size during the latter stages of oogenesis, became enlarged again. This is interpreted as denoting synthesis but not release of CA hormone. In meat-fed mated flies, cycles of oviposition and oogenesis were reflected in the rise and fall in activity of the MNC and CA. The MNC and CA of male flies also responded to the ingestion of a protein meal, and the activity of these tissues persisted for several days before it declined. The similar response of the MNC and CA in both males and females demonstrates the importance of a meat meal to reproduction in this species: in females it is required for oogenesis, but its ingestion by both sexes is necessary for overall reproductive success.