Data from: Considerations used by desert isopods to assess scorpion predation risk

Animals adjust behaviors to balance changes in predation risk against
other vital needs. Animals must therefore collect sensory information and
use complex risk assessment process that estimates risks and weigh costs
and benefits entailed in different reactions. Studying this cognitive
process is challenging, especially in nature because it requires inferring
sensory abilities and conscious decisions from behavioral reactions. Our
goal was to address this empirical challenge by implementing
psychophysical principles to field research that explores considerations
used by desert isopods (Hemilepistus reaumuri) to assess the risk of
scorpions that hunt exclusively from within their burrows. We introduced
various combinations of chemical and physical cues to the vicinity of the
isopods' burrows and recorded their detailed reactions upon first
encountering the cues. The isopods reacted defensively to scorpion odor
but only when accompanied with excavated-soil or other odors typically
found near scorpion burrows. Isopods also reacted defensively to piles of
excavated soil without scorpion olfactory cues, suggesting that isopods
take precautions even against physical disturbances that do not
necessarily reflect predator activity. Simultaneous presence of different
cues provoked graded responses, possibly reflecting an additive increase
in risk estimation. We conclude that wild isopods use defensive reactions
toward environmental signals only when the integrated perceptual
information implies an active scorpion burrow, or when they lack data to
refute this possibility.