Host manipulation is a common parasite strategy to alter host behavior in a manner to enhance parasite fitness usually by increasing the parasite's transmission to the next host. In nature, hosts often harbour multiple parasites with agreeing or conflicting interests over host manipulation. Natural selection might drive such parasites to cooperation, compromise or sabotage. Sabotage would occur, if one parasite suppresses the manipulation of another. Experimental studies on the effect of multi-parasite interactions on host manipulation are scarce, clear experimental evidence for sabotage is elusive. We tested the effect of multiple infections on host manipulation using lab bred copepods experimentally infected with the trophically transmitted tapeworm Schistocephalus solidus. This parasite is known to manipulate its host depending on its own developmental stage. Coinfecting parasites with the same aim enhanced each other's manipulation but only after reaching infectivity. If the coinfecting parasites disagree over host manipulation, the infective parasite wins this conflict: the non-infective one has no effect. The winning (i.e. infective) parasite suppresses the manipulation of its non-infective competitor. This presents conclusive experimental evidence for both cooperation in and sabotage of host manipulation and hence a proof of principal that one parasite can alter and even neutralize manipulation by another.
data_experiment1: intraspecific conflict and cooperation
Worksheet 1 ("copepods") contains information on each copepod used in the study including dead or incorrectly infected copepods. Worksheet 2 ("behavior") contains the behavior of only those copepods that survived until their infection status could be determined and that were infected by all parasites they had been exposed to. No behavior was recorded for any of the other copepods. The behavior consists of the position of each copepod every two seconds during one minute after a simulated predation attack and after a recovery period and, resulting from this whether or how far they moved during this time interval. This data was obtained from video recordings of copepod behavior using the manual tracking tool in imageJ and was done blindly as to the infection status of each copepod.
data_experiment1.xls
data_experiment2_effect_of_parasite_number_on_intraspecific_conflict
Worksheet 1 ("copepods") contains information on each copepod used in the study including dead or incorrectly infected copepods. Worksheet 2 ("behavior") contains the behavior of only those copepods that survived until their infection status could be determined and that were infected by all parasites they had been exposed to. No behavior was recorded for any of the other copepods. The behavior consists of the position of each copepod every two seconds during one minute after a simulated predation attack and after a recovery period and, resulting from this whether or how far they moved during this time interval. This data was obtained from video recordings of copepod behavior using the manual tracking tool in imageJ and was done blindly as to the infection status of each copepod.
data_experiment2.xls
data_preliminary_experiment: Parasite size and effect of parasite number on an intraspecific conflict
Data for supplementary results 2. Worksheet 1 ("copepods") contains information on each copepod used in the study including dead or incorrectly infected copepods. Worksheet 2 ("behavior") contains the behavior of only those copepods that survived until their infection status could be determined and that were infected by all parasites they had been exposed to. No behavior was recorded for any of the other copepods. The behavior consists of the position of each copepod every two seconds during one minute after a simulated predation attack and after a recovery period and, resulting from this whether or how far they moved during this time interval. This data was obtained from video recordings of copepod behavior using the manual tracking tool in imageJ and was done blindly as to the infection status of each copepod.
data_preliminary_experiment.xlsx