TY - JOUR
T1 - Individual variation in testosterone and parental care in a female songbird; The dark-eyed junco (Junco hyemalis)
AU - Cain, Kristal E.
AU - Ketterson, Ellen D.
PY - 2013/9
Y1 - 2013/9
N2 - When competition for sex-specific resources overlaps in time with offspring production and care, trade-offs can occur. Steroid hormones, particularly testosterone (T), play a crucial role in mediating such trade-offs in males, often increasing competitive behaviors while decreasing paternal behavior. Recent research has shown that females also face such trade-offs; however, we know little about the role of T in mediating female phenotypes in general, and the role of T in mediating trade-offs in females in particular. Here we examine the relationship between individual variation in maternal effort and endogenous T in the dark-eyed junco, a common songbird. Specifically, we measure circulating T before and after a physiological challenge (injection of gonadotropin releasing hormone, GnRH), and determine whether either measure is related to provisioning, brooding, or the amount of T sequestered in egg yolk. We found that females producing more T in response to a challenge spent less time brooding nestlings, but provisioned nestlings more frequently, and deposited more T in their eggs. These findings suggest that, while T is likely important in mediating maternal phenotypes and female life history tradeoffs, the direction of the relationships between T and phenotype may differ from what is generally observed in males, and that high levels of endogenous T are not necessarily as costly as previous work might suggest.
AB - When competition for sex-specific resources overlaps in time with offspring production and care, trade-offs can occur. Steroid hormones, particularly testosterone (T), play a crucial role in mediating such trade-offs in males, often increasing competitive behaviors while decreasing paternal behavior. Recent research has shown that females also face such trade-offs; however, we know little about the role of T in mediating female phenotypes in general, and the role of T in mediating trade-offs in females in particular. Here we examine the relationship between individual variation in maternal effort and endogenous T in the dark-eyed junco, a common songbird. Specifically, we measure circulating T before and after a physiological challenge (injection of gonadotropin releasing hormone, GnRH), and determine whether either measure is related to provisioning, brooding, or the amount of T sequestered in egg yolk. We found that females producing more T in response to a challenge spent less time brooding nestlings, but provisioned nestlings more frequently, and deposited more T in their eggs. These findings suggest that, while T is likely important in mediating maternal phenotypes and female life history tradeoffs, the direction of the relationships between T and phenotype may differ from what is generally observed in males, and that high levels of endogenous T are not necessarily as costly as previous work might suggest.
KW - Dark-eyed junco (Junco hyemalis)
KW - Endogenous steroids
KW - Gonadotropin releasing hormone (GnRH)
KW - Life history tradeoffs
KW - Maternal care
KW - Testosterone
KW - Yolk hormones
UR - http://www.scopus.com/inward/record.url?scp=84884922669&partnerID=8YFLogxK
U2 - 10.1016/j.yhbeh.2013.09.002
DO - 10.1016/j.yhbeh.2013.09.002
M3 - Article
SN - 0018-506X
VL - 64
SP - 685
EP - 692
JO - Hormones and Behavior
JF - Hormones and Behavior
IS - 4
ER -