Rhesus macaques compensate for reproductive delay following ecological
adversity early in life
Abstract
Adversity early in life can shape the reproductive potential of
individuals through negative effects on health and lifespan. However,
long-lived populations with multiple reproductive events may present
alternative life history strategies to optimize reproductive schedules
and compensate for shorter lifespans when experiencing adversities early
in life. Here, we quantify the effects of major hurricanes and
density-dependence as sources of early-life ecological adversity on the
mean age-specific fertility, reproductive pace, and lifetime
reproductive success (LRS) of Cayo Santiago rhesus macaque females, and
explored demographic mechanisms for reproductive schedule optimization
later in life. Females experiencing major hurricanes early in life
exhibit a delayed reproductive debut, but maintain inter-birth intervals
and show a higher mean fertility during prime reproductive ages relative
to females experiencing no hurricanes. Increasing density at birth is
associated to a decrease in mean fertility and LRS. When combined, our
study reveals that early-life ecological adversities predict a
delay-overshoot pattern in mean age-specific fertility that supports the
maintenance of LRS. In contrast to predictive adaptive response models
of accelerated reproduction, the long-lived Cayo Santiago population
presents a novel reproductive strategy where females who experience
major natural disasters early in life ultimately overcome their initial
reproductive penalty with no overall negative fitness outcomes. Such
strategy suggests that investing more energy into development and
maintenance at younger ages allows long-lived females experiencing
early-life ecological adversity to reproduce at a mean rate equivalent
to that of a typical female cohort later in life.