DOI: 10.5061/dryad.4mw6m90g2
title: Data for: Experimental infections with Euhaplorchis californiensis and a small cyathocotylid increase conspicuous behaviors in California killifish (Fundulus parvipinnis)

description: Some parasites manipulate their host’s phenotype to enhance predation
 rates by the next host in the parasite’s life cycle. Our understanding of
 this “parasite-increased trophic-transmission” is often stymied by study
 design challenges. A recurring difficulty has been obtaining uninfected
 hosts with a coevolutionary history with the parasites, and conducting
 experimental infections that mimic natural processes. In 1996, Lafferty
 and Morris provided what has become a classic example of
 parasite-increased trophic-transmission; they reported a positive
 association between the intensity of a brain-infecting trematode
 (Euhaplorchis californiensis) in naturally infected California killifish
 (Fundulus parvipinnis) and the frequency of “conspicuous behaviors”, which
 was thought to explain the documented 10-30x increase in predation by the
 final host birds. Here, we address the primary gap in that study by using
 experimental infections to assess causality of E. californiensis infection
 for increased conspicuous behaviors in F. parvipinnis. We hatched and
 reared uninfected F. parvipinnis from a population co-occurring with E.
 californiensis, and infected them 1-2 times/week over half their life span
 with E. californiensis and a “small cyathocotylid” trematode (SMCY) that
 targets the host’s muscle tissue. At 3 time-points throughout the hosts’
 lives, we quantified several conspicuous behaviors: contorting, darting,
 scratching, surfacing, and vertical positioning relative to the water’s
 surface. Euhaplorchis californiensis and SMCY infection caused 1.8 and
 2.5-fold overall increases in conspicuous behaviors, respectively. Each
 parasite was also associated with increases in specific conspicuous
 behaviors, particularly 1.9 and 1.4-fold more darting. These experimental
 findings help solidify E. californiensis-F. parvipinnis as a classic
 example of behavioral manipulation. Yet our findings for E. californiensis
 infection-induced behavioral change were less consistent and strong than
 those previously documented. We discuss potential explanations for this
 discrepancy, particularly the idea that behavioral manipulation may be
 most apparent when fish are actively attacked by predators. Our findings
 concerning the other studied trematode species, SMCY, highlight that
 trophically transmitted parasites infecting various host tissues are known
 to be associated with conspicuous behaviors, reinforcing calls for
 research examining how communities of trophically transmitted parasites
 influence host behavior.
description: Please read "Experimental infections with Euhaplorchis californiensis and a small cyathocotylid increase conspicuous behaviors in California killifish (Fundulus parvipinnis)" by Weinersmith et al. (2023) in the Journal of Parasitology for details on methods.  Analysis - Weinersmith et al JP Final.R This file provides the R code used for all analyses and the creation of graphs for the manuscript. This file also includes the definitions of all variables included in the data files. Data - Conspicuous Behaviors for 2016 Cohort.csv This .csv file contains the data used to analyze the discrete conspicuous behaviors described in Table 1 of Weinersmith et al. (in press).  Data – Proportion Near the Water Surface for 2016 Cohort.csv This .csv file contains the data used to analyze the impact of infection on the proportion of fish found near the water surface.