The elephant in the family: Costs and benefits of elder siblings on
younger offspring life-history trajectory in a matrilineal mammalVérane
Berger, Sophie Reichert, Mirkka Lahdenperä, John Jackson, Win Htut & Virpi
LummaaJournal of Animal EcologySeptember 20, 2021 Abstract
Many mammals grow up with siblings, and interactions between them can
influence offspring phenotype and fitness. Among these interactions,
sibling competition between different-age offspring should lead to
reproductive and survival costs on the younger sibling, while sibling
cooperation should improve younger sibling's reproductive potential and
survival. However, little is known about the consequences of sibling
effects on younger offspring life-history trajectory, especially in
long-lived mammals.
We take advantage of a large, multigenerational demographic dataset from
semi-captive Asian elephants to investigate how the presence and sex of
elder siblings influence the sex, survival until 5 years old, body
condition, reproductive success (i.e. age at first reproduction and
lifetime reproductive success) and long-term survival of subsequent
offspring.
We find that elder siblings have heterogeneous effects on subsequent
offspring life-history traits depending on their presence, their sex and
the sex of the subsequent offspring (named focal calf).
Overall, the presence of an elder sibling (either sex) strongly
increased focal calf long-term survival (either sex) compared to sibling
absence. However, elder sisters had higher impact on the focal sibling than
elder brothers. Focal females born after a female display higher long-term
survival, and decreased age at first reproduction when raised together with
an elder sister rather than a brother. Focal males born after a female
rather than a male showed lower survival but higher body weight when both
were raised together. We did not detect any sibling effects on the sex of
the focal calf sex, survival until 5 years old and lifetime reproductive
success.
Our results highlight the general complexity of sibling effects, but
broadly that elder siblings can influence the life-history trajectory of
subsequent offspring. We also stress the importance of considering all life
stages when evaluating sibling effects on life trajectories.
FULL PAPER PDF
LINKhttps://drive.google.com/file/d/1UrN6Y0bv7Uu80ywNcXXuqcfxtP29Ks7f/view?usp=sharing
https://drive.google.com/file/d/1UrN6Y0bv7Uu80ywNcXXuqcfxtP29Ks7f/view?usp=sharing
FULL
PAPER WEB
LINKhttps://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.13573
https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.13573