Condition- and parasite-dependent expression of a male-like trait in a female bird.
In many species, females display brightly coloured and elaborate traits similar to those that males use in intra- and inter-sexual selection processes. These female characters are sometimes related to fitness, and might function as secondary sexual characteristics that have evolved through sexual selection. Here, we used descriptive data from 674 females in 10 populations and an experimental removal of Trichostrongylus tenuis parasites in four populations, to examine the effects of season, age, condition, and parasites on the size of supra-orbital combs displayed by female red grouse Lagopus lagopus scoticus. We found that comb size (i) was greater during the breeding than the non-breeding season, (ii) was greater in adult than in young females, (iii) was positively correlated with body condition, and (iv) negatively correlated with parasite abundance. Experimentally, we showed that comb size increased proportionally to the number of worms removed after parasite dosing. Our findings provide a better understanding of proximate mechanisms behind the expression of a male-like trait in females, and we discuss its possible function as a female ornament.
Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain. j.mart@mncn.csic.es
J
J
Martinez-Padilla
P
P
Vergara
L
L
Pérez-Rodríguez
F
F
Mougeot
F
F
Casas
S C
SC
Ludwig
J A
JA
Haines
M
M
Zeineddine
S M
SM
Redpath
D000375:Aging; D000818:Animals; D003129:Comb and Wattles / Q000502:physiology*; D005260:Female; D046094:Galliformes / Q000469:parasitology / Q000502:physiology*; D006790:Host-Parasite Interactions; D008297:Male; D012621:Seasons; D014254:Trichostrongylus / Q000502:physiology*
Science. 1998 Dec 18;282(5397):2256-8
9856948
Evolution. 1980 Mar;34(2):292-305
28563426
Proc Biol Sci. 2004 May 7;271(1542):925-30
15255047
J Evol Biol. 2008 Jan;21(1):226-233
18034808
J Helminthol. 2004 Mar;78(1):69-76
14972040
Proc Biol Sci. 2000 Apr 7;267(1444):665-70
10821610
Proc Biol Sci. 2005 Nov 7;272(1578):2299-304
16191643