Data from: Does predation risk affect mating behavior? An experimental test in dumpling squid (Euprymna tasmanica)

Introduction: One of the most important trade-offs for many animals is
that between survival and reproduction. This is particularly apparent when
mating increases the risk of predation, either by increasing
conspicuousness, reducing mobility or inhibiting an individual’s ability
to detect predators. Individuals may mitigate the risk of predation by
altering their reproductive behavior (e.g. increasing anti-predator
responses to reduce conspicuousness). The degree to which individuals
modulate their reproductive behavior in relation to predation risk is
difficult to predict because both the optimal investment in current and
future reproduction (due to life-history strategies) and level of
predation risk may differ between the sexes and among species. Here, we
investigate the effect of increased predation risk on the reproductive
behavior of dumpling squid (Euprymna tasmanica). Results: Females, but not
males, showed a substantial increase in the number of inks (an
anti-predator behavior) before mating commenced in the presence of a
predator (sand flathead Platycephalus bassensis). However, predation risk
did not affect copulation duration, the likelihood of mating, female
anti-predator behavior during or after mating or male anti-predator
behavior at any time. Conclusions: Inking is a common anti-predator
defense in cephalopods, thought to act like a smokescreen, decoy or
distraction. Female dumpling squid are probably using this form of defense
in response to the increase in predation risk prior to mating. Conversely,
males were undeterred by the increase in predation risk. A lack of change
in these variables may occur if the benefit of completing mating outweighs
the risk of predation. Prioritizing current reproduction, even under
predation risk, can occur when the chance of future reproduction is low,
there is substantial energetic investment into mating, or the potential
fitness payoffs of mating are high.