Data from: The sources of variation for individual prey-to-predator size ratios

The relative body size at which predators are willing to attack prey, a
key trait for predator-prey interactions, is usually considered invariant.
However, this ratio can vary widely among individuals or populations.
Identifying the range and origin of such variation is key to understanding
the strength and constraints on selection in both predators and prey.
Still, these sources of variation remain largely unknown. We filled this
gap by measuring the genetic, maternal and environmental variation of the
maximum prey-to-predator size ratio (PPSRmax) in juveniles of the wolf
spider Lycosa fasciiventris using a paternal half-sib split brood design,
in which each male was paired with two different females and the offspring
reared in two different food environments: poor and rich. Each juvenile
spider was then sequentially offered crickets of decreasing size and the
maximum prey size killed was determined. We also measured body size and
body condition of spiders upon emergence and just before the trial. We
found low, but significant heritability (h2=0.069) and dominance and
common environmental variance (d2+4c2=0.056). PPSRmax was also partially
explained by body condition (during trial) but there was no effect of the
rearing food environment. Finally, a maternal correlation between body
size early in life and PPSRmax indicated that offspring born larger were
less predisposed to feed on larger prey later in life. Therefore, PPSRmax,
a central trait in ecosystems, can vary widely and this variation is due
to different sources, with important consequences for changes in this
trait in the short and long terms.