Tackling diversity: new technologies to explore insect function

Insects dominate our world, with as many insect species as all other living organisms combined. With both beneficial (e.g. pollination) and harmful (e.g. malaria, dengue) impacts on our society, it is clearly important to better understand how insects work. But in the face of extraordinary biodiversity (perhaps tens of millions of species), where do we begin? Over several years, our lab has developed a framework for such analysis; while much of our work is in the famous model Drosophila (a small fruit fly), we have rationally selected other species that are representative of the major insect Orders, and so provide a way of sampling insect biodiversity. New advances in sequencing have made it possible to find out which genes are being used (expressed) in individual cells, so the time is now perfect to find out for the first time how insect tissues - in our case, the insect's 'kidney' - truly function. The benefits of this approach will be felt, not just in our fundamental understanding of this tissue and its many roles, but in biomedicine, as the insect kidney faithfully models several human renal diseases; but also in insect control, where it may be possible to selectively knock down the function of harmful but not beneficial insects, so producing more selective insect control measures.

Insects are the most biodiverse clade on the planet, with perhaps 10 million species, and are able to exploit niches from the Antarctic to the equator. Part of their success is the adaptability of their bodyplan, combined with an excellent ability to regulate their internal environment. To this end, the key osmoregulatory tissue, the Malpighian (renal) tubule has been studied extensively. A step change in our understanding of insect renal function was achieved by combining classical physiology with the molecular genetic approaches possible in the fruit fly, Drosophila melanogaster, and it became clear that, at least in this species and most Diptera, renal secretory function is split between multiple cell types. Larger principal cells actively transport cations, while smaller stellate cells regulate the shunt conductance of chloride and mediate water flux through aquaporins. With the advent of powerful sequencing technologies such as single-cell RNAseq, now is the perfect time to test this model across the major insect Orders, and to establish whether the functions identified in Drosophila are indeed performed generally across all insect tubules, and if so whether different functions are ascribable to different subpopulations of cells, or are performed in a uniform cell type. Critically, this molecular and informatic analysis is anchored in a laboratory with a reputation for physiological analysis , and with a published history of working with multiple insect Orders; so this combined molecular / informatic /physiological approach will be able to rewrite our understanding of insect renal function, with attendant benefits for both biomedicine and agriculture.