PREPRINT | Incorporating host traits into analysis of parasite life-history reveals facilitation in coinfection experiments

Gupta, V., Szadkowski, M., Carbonell, D., Moury, B., Duncan A,B. Incorporating host traits into analysis of parasite life-history reveals facilitation in coinfection experiments. BioRXiv, October 5, 2026

This article is a preprint and has not been certified by peer review

DOI : 10.1101/2025.09.13.675757v6

Abstract: Coinfection, when hosts are infected with more than one parasite, can modify life-history traits of both parasites and their host. We investigated reciprocal interactions between tomato spotted wilt virus (TSWV) and a non-vector spider mite, Tetranychus urticae, in coinfections on tomato plants. We compared the number of T. urticae daughters and adults and the viral load for two TSWV isolates (France81, which is more virulent, and LYE1137vir) in single and coinfections, and measured host traits (height, fresh weight, chlorophyll content, and number of flowers).

TSWV infection reduced plant height, weight, flowers and chlorophyll content, especially when infected with isolate France81. T. urticae only reduced plant height. The more virulent TSWV isolate facilitated spider mites by increasing the number of daughters per unit of plant height, thus potentially enabling equivalent levels of mite transmission as from virus-free plants. In contrast, there was no effect of T. urticae on the load of either TSWV isolate.

This work highlights the importance of incorporating measures of host life-history traits when investigating the consequences of coinfection for parasite fitness.