TY - JOUR
T1 - A further cost for the sicker sex? Evidence for male-biased parasite-induced vulnerability to predation
AU - Stevenson, Jessica F.
AU - Kinsella, Cormac
AU - Cable, Joanne
AU - Van Oosterhout, Cock
N1 - © 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
PY - 2016/4
Y1 - 2016/4
N2 - 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 male-biased parasite-induced vulnerability for the evolutionary ecology of this host-parasite interaction in natural communities.
AB - 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 male-biased parasite-induced vulnerability for the evolutionary ecology of this host-parasite interaction in natural communities.
KW - parasite-induced vulnerability to predation
KW - sex-biased parasitism
KW - Poecilia reticulata
KW - Gyrodactylus
KW - Bateman's principle for immunity
KW - infection tolerance
U2 - 10.1002/ece3.2049
DO - 10.1002/ece3.2049
M3 - Article
VL - 6
SP - 2506
EP - 2515
JO - Ecology and Evolution
JF - Ecology and Evolution
SN - 2045-7758
IS - 8
ER -