Butterworth, N.J., Lush, J., Moore, K., Hall, M.D. (2025). The sicker sex is plastic: Thermal plasticity determines sex biases in pathogen transmission

Merging two previously disparate concepts – sex-specific plasticity and disease dynamics, we reveal that the identity of the "sicker" sex within a species is not fixed, but rather entirely contingent upon the thermal environment. We demonstrate a simple but important outcome: male-biased transmission at cold temperatures, and female-biased transmission at warm temperatures. As global temperatures continue to rise, our results show how sex-specific plasticity fundamentally dictates whether pathogen transmission rates skew towards males or females.