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Updated: Aug 2, 2025

Establishment of Viral Infection and Analysis of Host-Virus Interaction in Drosophila Melanogaster
Published on: March 14, 2019
Limited host availability disrupts the genetic correlation between virulence and transmission
Diogo P Godinho1, Leonor R Rodrigues1, Sophie Lefèvre2
1cE3c: Centre for Ecology, Evolution, and Environmental Changes, Faculty of Sciences, University of Lisbon, Lisboa, Portugal.
Abstract:
Virulence is expected to be linked to parasite fitness via transmission. However, it is not clear whether this relationship is genetically determined, nor if it differs when transmission occurs continuously during, or only at the end of, the infection period. Here, we used inbred lines of the macroparasitic spider mite Tetranychus urticae to disentangle genetic vs. nongenetic correlations among traits, while varying parasite density and opportunities for transmission. A positive genetic correlation between virulence and the number of transmitting stages produced was found under continuous transmission. However, if transmission occurred only at the end of the infection period, this genetic correlation disappeared. Instead, we observed a negative relationship between virulence and the number of transmitting stages, driven by density dependence. Thus, within-host density dependence caused by reduced opportunities for transmission may hamper selection for higher virulence, providing a novel explanation as to why limited host availability leads to lower virulence.
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