Tetracycline has no long-term effects on gut physiology and microbiome of the New World screwworm, Cochliomyia hominivorax, which has positive implications for transgenic male-only rearing systems.

Authors: Arp, Alex; Tietjen, Mackenzie; SAGEL, AGUSTIN - US Department Of Agriculture (USDA); VASQUEZ, MARIO - US Department Of Agriculture (USDA); QUINTERO, GLADYS - US Department Of Agriculture (USDA); Bodine, Deanna; Saelao, Perot; Hickner, Paul

Submitted to: Genes, Genomes, Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2025
Publication Date: 3/25/2025
Citation: Arp, A.P., Tietjen, M., Sagel, A., Vasquez, M., Quintero, G., Bodine, D.M., Saelao, P., Hickner, P.V. 2025. Tetracycline has no long-term effects on gut physiology and microbiome of the New World screwworm, Cochliomyia hominivorax, which has positive implications for transgenic male-only rearing systems.. Genes, Genomes, Genetics. https://doi.org/10.1093/g3journal/jkaf058.
DOI: https://doi.org/10.1093/g3journal/jkaf058

Interpretive Summary: Insect control programs utilizing the sterile insect technique (SIT) are more efficient when all insects released are male. One approach to producing all males in a mass-rearing setting is development of tetracycline-repressible (Tet-Off) transgenic sexing systems. Tetracycline can have adverse impacts on insect health, therefore we reared screwworm, Cochliomyia hominivorax, like Tet-Off strains to investigate the impact on fitness, the midgut microbiota, and midgut transcriptomes. Overall, the impacts on the microbiota and transcriptome did not have adverse effects on the strain fitness, and changes caused by tetracycline exposure were not inherited by the offspring mimicking a male-only generation.

Technical Abstract: Tetracycline repressible (Tet-Off) male-only sexing systems have great potential for improving the efficacy of sterile insect control programs in addition to reductions in rearing cost. Insects’ close relationship with microbial symbionts and physiological stress caused by tetracycline class antibiotics, poses concern that Tet-Off strains will have reduced fitness and efficacy of flies carrying these traits. Here we evaluated the biological performance, midgut microbiome, and midgut transcriptomes of wild-type screwworm, Cochliomyia hominivorax, reared in diet without Tc (pre-Tc), with Tc (on-Tc), or a pseudo “male-only” condition where offspring of the Tc fed line were reared without Tc (post-Tc), like Tet-Off strains previously developed for this species. Biological performance was not significantly changed by the inclusion of Tc in the diet, and in most cases the flies reared with Tc were generally more fit than lines reared without Tc. The gut microbiome and transcriptome revealed interesting and similar pattens. In both surveys, the greatest changes were between both pre-Tc and post-Tc treatments and the on-Tc treatment. Very few differences were observed between pre-Tc and post-Tc groups, suggesting that there are few negative persistent effects of Tc exposure to fly colonies, and flies revert to their natural state rapidly after the removal of Tc. These results suggest there are limited negative impacts of Tet-Off regulatory systems for use by the C. hominivorax eradication program, and differences observed in Tet-Off strain performance are likely not related to Tc exposure.