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Corticosterone manipulation reveals differences in hierarchical organization of multidimensional reproductive trade‐offs in r‐strategist and K‐strategist females
Author(s) -
LANCASTER L. T.,
HAZARD L. C.,
CLOBERT J.,
SINERVO B. R.
Publication year - 2008
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2007.01478.x
Subject(s) - biology , corticosterone , strategist , trade off , offspring , foraging , zoology , ecology , endocrinology , hormone , pregnancy , genetics , marketing , business
Life history trade‐offs are often hierarchical with decisions at one level affecting lower level trade‐offs. We investigated trade‐off structure in female side‐blotched lizards ( Uta stansburiana ), which exhibit two evolved strategies: yellow‐throated females are K‐strategists and orange‐throated are r‐strategists. Corticosterone treatment was predicted to differentially organize these females’ reproductive decisions. Corticosterone‐treated yellow females suppressed reproduction but survived well, and augmented egg mass without decreasing clutch size. Conversely, corticosterone enhanced mortality and reproductive rates in orange females, and increased egg mass only after lengthy exposure. Corticosterone did not affect post‐laying condition, suggesting that corticosterone increased egg mass through enhanced energy acquisition (income breeding). Corticosterone enhanced survival of lightweight females, but decreased survival of heavy females, introducing a foraging vs. predation trade‐off. We conclude that rather than being a direct, functional relationship, observed trade‐offs between offspring size and number represent evolved differences in hierarchical organization of multidimensional trade‐offs, particularly in response to stress.