DOI: 10.5061/dryad.1vhhmgr5b
title: Hamiltosporidium tvaerminnensis infection route diet quality

description: Linking characteristics of parasites to host diet-induced shifts in
 host-parasite interactions is a critical step in predicting the abundance
 of specific parasites within an ecosystem. A parasite’s infection route
 reflects a suite of parasite characteristics that could mediate the
 effects of host diet quality on host-parasite interactions, but the effect
 of infection route on the response of host-parasite interactions to host
 diet quality has not been quantified. We quantified these effects for the
 first time by experimentally manipulating a parasite capable of
 transmitting itself via multiple pathways utilized by a wide variety of
 parasites. We altered the diet phosphorus (P) content of Daphnia infected
 by the mixed mode transmitter Hamiltosporidian tvaerminnensis via one of
 two infection routes: horizontal, via the ingestion of spores from dead
 hosts, or vertical, via the infection of host offspring. Then, we
 quantified the effect of infection route on host diet-induced shifts in
 parasite load and virulence (i.e. host fecundity and survival). Overall,
 we found that horizontal infections were more sensitive to host diet than
 vertical infections. Low P diets decreased the parasite load and fecundity
 of all hosts, but had stronger negative effects on the loads of
 horizontally infected individuals than vertically infected ones. Likewise,
 horizontal infection reduced the survival of hosts fed low P (but not high
 P) diets while vertical infection did not affect survival. This increased
 sensitivity of horizontal infections to diet quality empirically supports
 the intuitive hypothesis that host diet quality exerts stronger effects on
 parasites that transmit via ingestion into a host’s gut than on parasites
 that transmit via routes less directly related to host nutrient uptake.
 Through these effects, host diet quality may shape the ecology and
 evolution of parasite communities.
description: # Hamiltosporidium tvaerminnensis infection route diet quality
 [https://doi.org/10.5061/dryad.1vhhmgr5b](https://doi.org/10.5061/dryad.1vhhmgr5b) ## Description of the data and file structure *Hamiltosporidium tvaerminnensis* was used to infect *Daphnia magna* via either vertical or horizontal infection routes. Individual spore load, fecundity, and survival were recorded for horizontally infected, vertically infected, and uninfected *D. magna* fed high and low phosphorus diets for 28 days. ### Files and variables #### File: Oikos\_Infection\_Route\_Phosphorus.csv **Description:**  ##### Variables * Diet Phosphorus: The relative amount of phosphorus in the algal (*Scenedesmus obliquus*) diet fed to *Daphnia (high or low).* * Infection Route: The route used to infect *Daphnia* (Horizontal or Vertical or Uninfected). * Individual: The identifying number of each individually housed *Daphnia*. * Dead Day: The Day of the experiment (1-28) the individual was found dead. n/a indicates the individual survived the duration of the experiment. * Dead: If the animal died during the 28 day experiment (yes or no). * Fecundity (#offspring/28days): The number of offpsring produced by each individual throughout the experiment. n/a indicates that fecundity data was not available for this sample. * Spore Load (spores/ug): Number of spores per ug of daphnia dry mass. n/a indicates that spores were not counted for this sample.