Silver spoons, reproduction, and growth catch-up in eastern Grey kangaroos

Kelly Forrester, Andrew M MacDonald and Marco Festa-Bianchet

Behavioral Ecology, 2025, vol. 36, issue 3, 998-1007

Abstract: Early growth and environmental conditions can shape life-history trajectories. Long-lived iteroparous species with indeterminate growth face growth-reproduction trade-offs for most of their lives. Poor early conditions can delay primiparity and restrict growth, potentially compensated for by faster growth later in life, at the cost of reduced reproduction. We explored the variation in age at primiparity and early reproduction in eastern Grey kangaroos, based upon 13 yr of monitoring about 100 known-age females. We then examined associations between early reproduction, later reproduction, and lifetime growth. We used a modified von Bertalanffy growth function to model the indeterminate growth of females and to test the effects of early reproduction on lifetime growth. Favorable environmental conditions, large size, and condition as a subadult led to earlier reproduction and higher reproductive success at ages 3 to 5. As females aged, size and condition had diminishing effects on reproductive success. Females with greater early-adulthood reproduction had slightly higher reproduction later in life. We did not detect a growth cost of early reproduction. Large females in good condition favored early reproduction over growth, while those with poor early growth exhibited growth catch-up at the cost of reproduction both early and later in life. As reported for other long-lived iteroparous species with indeterminate growth, female kangaroos prioritize growth over reproduction for much of their lifespan. Eastern Gray kangaroos show heterogeneity in early growth and reproductive strategies. Early primiparity and reproduction are constrained by body condition, size, and environmental conditions when females are pre-reproductive subadults.

Keywords: catch-up growth; early life growth; early reproduction; growth reproduction trade-offs; indeterminate growth; life history theory; silver spoon effects; von Bertalanffy growth function (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
http://hdl.handle.net/10.1093/beheco/araf017 (application/pdf)
Access to full text is restricted to subscribers.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:oup:beheco:v:36:y:2025:i:3:p:998-1007.

Ordering information: This journal article can be ordered from
https://academic.oup.com/journals

Access Statistics for this article

Behavioral Ecology is currently edited by Louise Barrett

More articles in Behavioral Ecology from International Society for Behavioral Ecology Oxford University Press, Great Clarendon Street, Oxford OX2 6DP, UK.
Bibliographic data for series maintained by Oxford University Press ().