1 Citation 108 Views 8 Downloads
Human-driven increases in global mean temperatures are associated with
concomitant increases in thermal variability. Yet, few studies have
explored the impacts of thermal variability on fitness-related traits,
limiting our ability to predict how organisms will respond to dynamic
thermal changes. Among the myriad organismal responses to thermal
variability, one of the most proximate to fitness – and, thus, a
population’s ability to persist - is reproduction. Here, we examine how a
model freshwater fish (Danio rerio) responds to diel thermal fluctuations
that span the species’ viable developmental range of temperatures. We
specifically investigate reproductive performance metrics including
spawning success, fecundity, egg provisioning, and sperm concentration.
Notably, we apply thermal variability treatments during two ontogenetic
timepoints to disentangle the relative effects of developmental plasticity
and reversible acclimation. We found evidence of direct, negative effects
of thermal variability during later ontogenetic stages on reproductive
performance metrics. We also found complex interactive effects of early
and late-life exposure to thermal variability, with evidence of beneficial
acclimation of spawning success and modification of the relationship
between fecundity and egg provisioning. Our findings illuminate the
plastic life-history modifications that fish may undergo as their thermal
environments become increasingly variable.
108 views reported since publication in 2022.