Host avoidance and resistance vary independently and are specific to parasite genotype

Hosts can reduce the negative fitness effects of parasite infection by avoiding contact with parasites or by resisting infection after contact. Because of their shared outcome, avoidance and resistance have been hypothesized to trade off with one another. Assuming these defenses carry fitness costs, hosts are expected to have high levels of one defense or the other, but not both. Alternatively, avoidance and resistance may covary positively, if, for example, they complement one another or are genetically or mechanistically linked. Testing these hypotheses requires measuring avoidance and resistance independently, which is challenging because they are functionally linked. In this study, we separated avoidance and resistance of the host C. elegans against the bacterial parasite S. marcescens and tested for a correlation between them. We phenotyped a panel of 12 genetically divergent hosts using two distinct bacterial strains and multiple experimental contexts. We found no evidence of a co..., Overview
We examined the relationship between avoidance and resistance to two distinct strains of the opportunistic bacterial parasite S. marcescens across 12 genetically divergent strains of C. elegans. We chose parasite strains that we expected to differ in their virulence and the avoidance they elicit. We assayed resistance independently of avoidance by measuring survival after directly dosing hosts in liquid, which prevents hosts avoiding the parasite. We used two assays to measure avoidance: a lawn-leaving assay (Pradel et al., 2007) and a choice assay (Schulenburg & Müller, 2004). These are two common designs used for assessing behavioral responses to bacteria, and we expected they would capture different aspects of behavioral variation. We used data from these assays to test whether resistance and avoidance covaried across C. elegans strains. Each assay was conducted in a blocked design, with a different subset of host strains tested in each of four to five experimental block..., # Data from: Host avoidance and resistance vary independently and are specific to parasite genotype

Dataset DOI: [10.5061/dryad.gxd254804](10.5061/dryad.gxd254804)

## Description of the data and file structure

This study examined the correlation between avoidance and resistance of the nematode host *Caenorhabditis elegans* to the bacterial parasite *Serratia marcescens*. We measured avoidance with two behavioral assay: a lawn-leaving assay and a choice assay. We measured resistance as survival in liquid culture with the parasite.

The host strains were assigned a numeric label to facilitate interpretation of the figures in the main text. This is the assignment of labels to host strains, which can also be found in the electronic supplementary materials.

| Label | Host strain |
| :---- | :---------- |
| 1 | DL238 |
| 2 | MY16 |
| 3 | JT11398 |
| 4 | N2 |
| 5 | EG4725 |
| 6 | CB4856 |
| 7 | CX11314 |
| 8 | MY23 ...,