Advancing the sterile insect technique for the New World screwworm fly: the case for CRISPR-engineered genetic sexing strains.

Abstract

The sterile insect technique (SIT) has long been a cornerstone of area-wide integrated pest management programs, and the eradication of the New World screwworm Cochliomyia hominivorax (Coquerel) from North and Central America is widely regarded as a landmark success. However, its resurgence underscores the need to modernize SIT strategies against this devastating pest. The development of genetic sexing strains (GSS) is a revolutionary idea supporting SIT, enabling efficient large-scale separation and the exclusive release of sterile males. Despite GSSs having been shown to significantly enhance the cost-effectiveness and field efficacy of operational SIT campaigns, no such sexing systems have yet been developed for C. hominivorax. Given recent advances in insect genomics, we consider the development of a screwworm GSS both feasible and timely. In this forum, we critically evaluate the potential for translating decades of GSS research into C. hominivorax by leveraging the CRISPR/Cas9 gene-editing technology. To make evidence accessible to a broader audience, we present a narrative overview covering the (i) genetics of GSSs, (ii) current approaches for precise engineering of analogous sexing systems, (iii) knowledge gaps and technical challenges in developing CRISPR-engineered GSSs in screwworm, and (iv) regulatory landscape governing genome-edited insects in the Americas in comparison to other contemporaneous biotechnologies. We argue that establishing a screwworm GSS would provide immediate benefits to existing management programs and hope this synthesis will inform and encourage future studies on this effort.