Data from: A further cost for the sicker sex? Evidence for male-biased parasite-induced vulnerability to predation

  • Jessica Frances Stephenson (Creator)
  • Cormac Kinsella (Creator)
  • Joanne Cable (Creator)
  • Cock van Oosterhout (Creator)



Males are typically the sicker sex. Data from multiple taxa indicate that they are more likely to be infected with parasites, and are less “tolerant,” or less able to mitigate the fitness costs of a given infection, than females. One cost of infection for many animals is an increased probability of being captured by a predator. A clear, hitherto untested, prediction is therefore that this parasite-induced vulnerability to predation is more pronounced among males than females. We tested this prediction in the sexually size dimorphic guppy, Poecilia reticulata, in which females are typically larger than males. We either sham or experimentally infected guppies with Gyrodactylus turnbulli, elicited their escape response using an established protocol and measured the distance they covered during 60 ms. To discriminate between the effects of body size and those of other inherent sex differences, we size-matched fish across treatment groups. Infection with G. turnbulli reduced the distance covered during the escape response of small adults by 20.1%, whereas that of large fish was unaffected. This result implies that parasite-induced vulnerability to predation is male-biased in the wild: although there was no difference in escape response between our experimentally size-matched groups of males and females, males are significantly smaller across natural guppy populations. These results are consistent with Bateman's principle for immunity: Natural selection for larger body sizes and longevity in females seems to have resulted in the evolution of increased infection tolerance. We discuss the potential implications of sex- and size-biased parasite-induced vulnerability to predation for the evolutionary ecology of this host–parasite interaction in natural communities.

Usage notes:
StephensonetalData: These are the raw data from the experiment described in the paper. The variables are as follows: fish = fish identity; sex = fish sex; infected = whether or not the fish was infected; date.inf = the date the fish was infected; dayofinf = the number of days post infection that the fish was tested; gyrocount = the number of parasites on the fish at the time of testing; length = fish length; weight = fish weight; drop = the order of the ball drop; position = whether the fish was closer or further away from the ball when it dropped; distance = the distance covered in mm during the 60s of the escape response. NB this file only contains the response data - fish and ball drops that failed to respond have been excluded, as per our original analysis.
Date made available24 Feb 2017
PublisherDryad data repository
Geographical coverageTrinidad

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