Table 1.
Some examples of the magnitude of inter-individual variation for plasma hormone titres, other humoral components and other physiological traits.
| physiological trait | range | difference | standardized conditions or state and species | captive/free living | reference |
|---|---|---|---|---|---|
| hormone titres | |||||
| 17β-oestradiol | 0.2–2.2 ng ml−1 | 11-fold | egg production, zebra finch | C | E. Wagner (2007; personal communication) |
| 44–423 pg ml−1 | 10-fold | follicle development, starling | F | Williams et al. (2004) | |
| testosterone | 98–383 pg ml−1 | 4-fold | egg production, starling | F | Williams et al. (2004) |
| 1.8–11.9 ng ml−1 | 6-fold | early breeding, male junco | F | Jawor et al. (2006) | |
| prolactin | 3–25 ng ml−1 | 8-fold | osmotic challenge, tilapia | C | Seale et al. (2006) |
| corticosterone | 20–100 ng ml−1 | 5-fold | standard stressor, trout | C | Schjolden et al. (2005) |
| 75–358 ng ml−1 | 5-fold | baseline, non-manipulated, Phodopus | C | Guimont & Wynne-Edwards (2006) | |
| 0.6–10.4 | 15-fold | baseline, non-manipulated great tit | C | Cockrem & Silverin (2002) | |
| 1.8–46.5 pg ml−1 | 25-fold | baseline, non-manipulated, starling | F | Love et al. (2004) | |
| 10–60 ng ml−1 | 6-fold | baseline, incubation, eider | F | Bourgeon et al. (2006) | |
| other humoral components | |||||
| triglycerides | 0.3–3.0 mmol l−1 | 10-fold | mass-corrected | F | T.D. Williams (2004; unpublished data) |
| carotenoids | variousa | 5- to 6-fold | arrival date, incubation stage | F | Ninni et al. (2004) and Guimont & Wynne-Edwards (2006) |
| heat shock proteins | variousa | less than 4-fold | baseline, incubation, eider | F | Guimont & Wynne-Edwards (2006) |
| total anti-oxidants | 0.85–2.7 mM | less than 3-fold | incubation stage, blue tits | F | Tummeleht et al. (2006) |
| other physiological traits | |||||
| basal metabolic rate | variousa | 2-fold | mass-corrected | C | Chappell et al. (1999) and Russell & Chappell (2007) |
| mass-specific DEE | variousa | less than 2-fold | chick-provisioning | F | Williams & Vezina (2001) |
| heart rate | 300–420 bpm | less than 2-fold | Daphnia | C | Spicer & Gaston (1999) |
| muscle enzyme conc. | variousa | 3-fold | Hyla | F | James et al. (2005) |
| electrical signal duration | 60–135 ms | 2-fold | breeding, female, Pollimyrus | C | Crawford (1992) |
a
Includes multiple traits and/or multiple studies.