Modeling Control of Invasive Fire Ants by Gene Drive

The fire ant Solenopsis invicta is characterized by aggressive behavior and exceptional invasive capabilities, rendering conventional control methods largely ineffective. Here, we consider homing suppression gene drive in fire ants by developing a spatially explicit model that incorporates both monogyne and polygyne colonies. Ants may present unique challenges for gene drive due to their colony structure and haplodiploidy. Results show that after an extended period of time, gene drive effectively eliminates polygyne colonies, but monogyne populations can persist at low level. Though standard suppression drives in haplodiploids have reduced power, new dominant-sterile resistance or two-target strategies, as well as drives that affect the colony structure, can restore high suppressive capability. Interspecific competition can also exert a positive effect on gene drive suppression, especially if released during an initial invasion, enabling native ants to successfully recolonize their original habitats. Further, we identified several gRNA targets in conserved female fertility genes that may support efficient, low-resistance suppression drive designs. Overall, we conclude that while gene drive in fire ants may take place over extended time scales, its long-term results, even with imperfect efficiency, are promising.