Abstract
In birds and mammals with sexual size dimorphism (SSD), the larger sex is typically more sensitive to adverse environmental conditions, such as food shortage, during ontogeny. However, some recent studies of altricial birds have found that the larger sex is less sensitive, apparently because large size renders an advantage in sibling competition. Still, this effect is not an inevitable outcome of sibling competition, because several studies of other species of altricial birds have found the traditional pattern. We investigated if the sexes differ in environmental sensitivity during ontogeny in the blue tit, a small altricial bird with c. 6% SSD in body mass (males larger than females). We performed a cross-fostering and brood size manipulation experiment during 2 years to investigate if the sexes were differently affected as regards body size (body mass, tarsus and wing length on day 14 after hatching) and pre-fledging survival. We also investigated if the relationship between body size and post-fledging survival differed between the sexes. Pre-fledging mortality was higher in enlarged than in reduced broods, representing poor and good environments, respectively, but the brood size manipulation did not affect the mortality rate of males and females differently. In both years, both males and females were smaller on day 14 after hatching in enlarged as compared to reduced broods. In one of the years, we also found significant Sex × Experiment interactions for body size, such that females were more affected by poor environmental conditions than that of males. Body size was positively correlated with post-fledging survival, but we found no interactive effects of sex and morphological traits on survival. We conclude that in the blue tit, females (the smaller sex) are more sensitive to adverse environmental conditions which, in our study, was manifest in terms of fledgling size. A review of published studies of sex differences in environmental sensitivity in sexually size-dimorphic altricial birds suggests that the smaller sex is more sensitive than the larger sex in species with large brood size and vice versa.
Similar content being viewed by others
References
Anderson DJ, Budde C, Apanius V, Gomez JEM, Bird DM, Weathers WW (1993) Prey size influences female competitive dominance in estling American kestrels (Falco sparverius). Ecology 74:367–376
Badyaev AV (2002) Growing apart: an ontogenetic perspective on the evolution of sexual size dimorphism. Trends Ecol Evol 17:369–378
Badyaev AV, Hill GE, Beck ML (2003) Interaction between maternal effects: onset of incubation and offspring sex in two populations of a passerine bird. Oecologia 135:386–390
Bensch S (1999) Sex allocation in relation to parental quality. In: Adams N, Slotow R (eds) Proceedings of the 22nd Int. Ornithol. Congr., Durban BirdLife South Africa, Johannesburg, pp 451–466
Blank JL, Nolan V (1983) Offspring sex-ratio in red-winged blackbirds is dependent on maternal age. Proc Natl Acad Sci USA 80:6141–6145
Blondel J, Perret P, Anstett MC, Thebaud C (2002) Evolution of sexual size dimorphism in birds: test of hypotheses using blue tits in contrasted Mediterranean habitats. J Evol Biol 15:440–450
Bortolotti GR (1986) Influence of sibling competition on nestling sex-ratios of sexually dimorphic birds. Am Nat 127:495–507
Brodie ED III, Moore AJ, Janzen FJ (1995) Visualizing and quantifying natural selection. Trends Ecol Evol 10:313–318
Clutton-Brock TH, Albon SD, Guinness FE (1985) Parental investment and sex differences in juvenile mortality in birds and mammals. Nature 313:131–133
Dhondt AA (1970) The sex ratio of nestling great tits. Bird Study 17:282–286
Griffiths R, Double MC, Orr K, Dawson RJG (1998) A DNA test to sex most birds. Mol Ecol 7:1071–1075
Hipkiss T, Hornfeldt B, Eklund U, Berlin S (2002) Year-dependent sex-biased mortality in supplementary-fed Tengmalm’s owl nestlings. J Anim Ecol 71:693–699
Howe HF (1977) Sex-ratio adjustment in common grackle. Science 198:744–746
de Kogel CH (1997) Long-term effects of brood size manipulation on morphological development and sex-specific mortality of offspring. J Anim Ecol 66:167–178
Littell R, Milliken G, Stroup W, Wolfinger R (1996) SAS system for mixed models. SAS Institute Inc, Cary
Martins TLF (2004) Sex-specific growth rates in zebra finch nestlings: a possible mechanism for sex ratio adjustment. Behav Ecol 15:174–180
Merilä J (1996) Genetic variation in offspring condition: an experiment. Funct Ecol 10:465–474
Merilä J, Sheldon BC, Ellegren H (1997) Antagonistic natural selection revealed by molecular sex identification of nestling collared flycatchers. Mol Ecol 6:1167–1175
Nager RG, Monaghan P, Houston DC, Genovart M (2000) Parental condition, brood sex ratio and differential young survival: an experimental study in gulls (Larus fuscus). Behav Ecol Sociobiol 48:452–457
Newton I, Marquiss M (1979) Sex-ratio among nestlings of the european sparrowhawk. Am Nat 113:309–315
Nilsson J-Å, Gårdmark A (2001) Sibling competition affects individual growth strategies in marsh tit, Parus palustris, nestlings. Anim Behav 61:357–365
Oddie KR (2000) Size matters: competition between male and female great tit offspring. J Anim Ecol 69:903–912
Potti J, Davila JA, Tella JL, Frias O, Villar S (2002) Gender and viability selection on morphology in fledgling pied flycatchers. Mol Ecol 11:1317–1326
Richner H (1992) The effect of extra food on fitness in breeding carrion crows. Ecology 73:330–335
Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning, a laboratory manual. Cold Spring Harbour Laboratory Press, Cold Spring Harbour, NY
SAS Institute (1999) SAS OnlineDoc, V8. SAS Institute, Cary
Sayce JR, Hunt GL (1987) Sex-ratios of prefledging western gulls. Auk 104:33–37
Sheldon BC, Merilä J, Lindgren G, Ellegren H (1998) Gender and environmental sensitivity in nestling collared flycatchers. Ecology 79:1939–1948
Slagsvold T, Røskaft E, Engen S (1986) Sex-ratio, differential cost of rearing young, and differential mortality between the sexes during the period of parental care—fisher theory applied to birds. Ornis Scand 17:117–125
Smith HG, Källander H, Nilsson J-Å (1989) The trade-off between offspring number and quality in the great tit Parus major. J Anim Ecol 58:383–401
Stamps J, Clark A, Arrowood P, Kus B (1985) Parent–offspring conflict in budgerigars. Behaviour 94:1–40
Teather KL, Weatherhead PJ (1989) Sex-specific mortality in nestling great-tailed grackles. Ecology 70:1485–1493
Torres R, Drummond H (1997) Female-biased mortality in nestlings of a bird with size dimorphism. J Anim Ecol 66:859–865
Trivers RL, Willard DE (1973) Natural-selection of parental ability to vary sex-ratio of offspring. Science 179:90–92
Tschirren B, Fitze PS, Richner H (2003) Sexual dimorphism in susceptibility to parasites and cell-mediated immunity in great tit nestlings. J Anim Ecol 72:839–845
Acknowledgements
We thank Bengt Hansson and Henrik Smith for statistical advice, and Katrin Böhning-Gaese and anonymous reviewers for constructive comments on the manuscript. The study was financially supported by the Royal Swedish Academy of Science (to LR), Lunds Djurskyddsfond (to LR & MS), and the Swedish research council (to JÅN). The study was approved by the ethical committee for animal research, Malmö/Lund, Sweden (#126–00).
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by Katrin Böhning-Gaese
Rights and permissions
About this article
Cite this article
Råberg, L., Stjernman, M. & Nilsson, JÅ. Sex and environmental sensitivity in blue tit nestlings. Oecologia 145, 496–503 (2005). https://doi.org/10.1007/s00442-005-0133-1
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00442-005-0133-1