10.5061/DRYAD.NP5HQBZSD
Penczykowski, Rachel
0000-0003-4559-0609
Washington University in Saint Louis
Shocket, Marta
University of California Los Angeles
Housley Ochs, Jessica
Georgia Institute of Technology
Lemanski, Brian
Colgate University
Sundar, Hema
Georgia Institute of Technology
Duffy, Meghan
0000-0002-8142-0802
University of Michigan-Ann Arbor
Hall, Spencer
Indiana University Bloomington
Data from: Virulent disease epidemics can increase host density by
depressing foraging of hosts
Dryad
dataset
2021
FOS: Biological sciences
Daphnia dentifera
Metschnikowia bicuspidata
feeding rate
Host-parasite interaction
freshwater zooplankton
compensatory population growth
Feeding behavior
hydra effect
illness-mediated anorexia
trait-mediated indirect effect
National Science Foundation
https://ror.org/021nxhr62
DEB-0841679
National Science Foundation
https://ror.org/021nxhr62
DEB-0841817
National Science Foundation
https://ror.org/021nxhr62
DEB-1120316
2021-04-05T00:00:00Z
2021-04-05T00:00:00Z
en
187888 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
All else equal, parasites that harm host fitness should depress densities
of their hosts. However, parasites that alter host traits may increase
host density via indirect ecological interactions. Here, we show how
depression of foraging rate of infected hosts can produce such a hydra
effect. Using a foraging assay, we quantified reduced foraging rates of a
zooplankton host infected with a virulent fungal parasite. We then
parameterized a dynamical model of hosts, parasites, and resources with
this foraging function, showing how foraging depression can create a hydra
effect. Mathematically, the hydra arose when increased resource
productivity exceeded any increase in resource consumption per host.
Therefore, the foraging-mediated hydra effect more likely emerged (1) for
hosts that strongly control logistic-like resources and (2) during larger
epidemics of moderately virulent parasites. We then analyzed epidemics
from 13 fungal epidemics in nature. We found evidence for a
foraging-mediated hydra effect: large outbreaks depressed foraging rate
and correlated with increased densities of both algal resources and
Daphnia hosts. Therefore, depression of foraging rate of infected hosts
can produce higher host densities even during epidemics of parasites that
increase host mortality. Such hydras might prevent collapse of host
populations but also could produce higher densities of infected hosts.
This dataset contains data and code (MATLAB and R) for producing figures
1, 3, 4, 6, A1, and A3. Details of data collection can be found in the
online supplementary materials published with this article in American
Naturalist.
A README text file can be found in the .zip folder associated with each
figure. Figures 3, A3, 4, and 6 are plotted in MATLAB. To make Figures 1
and A1, foraging functions are fit to feeding rate data in MATLAB, and
then plots are created in R.