The hormonal and neural control of egg production in the historically important model insect, Rhodnius prolixus: A review, with new insights in this post-genomic era

Rhodnius prolixus, the blood gorging kissing bug, is a model insect, extensively used by Sir Vincent Wigglesworth and others, upon which the foundations of insect physiology, endocrinology, and development are built. It is also medically important, being a principal vector of Trypanosoma cruzi, the causative agent of Chagas disease in humans. The blood meal stimulates and enables egg production, and since an adult mated female can take several blood meals, each female can produce hundreds of offspring. Understanding the reproductive biology of R. prolixus is therefore of some critical importance for controlling the transmission of Chagas disease. The R. prolixus genome is available and so the post-genomic era has arrived for this historic model insect. This review focuses on the female reproductive system and coordination over the production of eggs, emphasizing the classical (neuro)endocrinological studies that led to a model describing inputs from feeding and mating, and the neural control of egg-laying. We then review recent insights brought about by molecular analyses, including transcriptomics, that confirm, support, and considerably extends this model. We conclude this review with an updated model describing the events leading to full expression of egg production, and also provide a consideration of questions for future exploration and experimentation.