‘Disease-smart’ outcrossing can enhance individual fitness and increase survival via immune priming against pathogens: New approaches to strengthen genetic rescue efforts

Abstract

We studied the potential of combining insect immune priming with the introduction of diverse migrants to safeguard individuals from an inbred population from disease as a technique for enhancing genetic rescue efforts. Immune priming in insects refers to the stronger immune response insects have against pathogens following exposure. This enhanced immunity can be passed on to offspring and holds promise for insect conservation efforts against diseases. We compared the fitness benefits to individuals from a small, inbred population of two treatments: the addition of genetically diverse migrants that had not been primed and the addition of immune-primed migrants. While both types of migrants enhanced reproduction, as in cases of genetic rescue, only primed migrants led to improved survival on exposure to a pathogen. Better immunity led to a trade-off with reproduction in immune-primed migrants, but this was not evident upon outcrossing with the target individuals, revealing synergies between hybrid vigour and immune priming. Given the demographic constraints and stochasticity that can exacerbate the effects of disease outbreaks in small populations, our results serve as a proof of concept for combining immune priming with assisted migration, which offers a proactive strategy to mitigate disease impacts while enhancing genetic diversity.