Data from: Effects of danger cues on mating interactions are size dependent in freshwater crayfish

Non-consumptive effects (NCEs) can have substantial effects on prey
populations. For example, they may alter mating interactions or interfere
with foraging behavior, with potential repercussions for the
entire community. Crayfish, the dominant macroinvertebrates in many
temperate freshwater ecosystems, are prey to many aquatic and terrestrial
species, and show behavioral responses to both predator and conspecific
alarm cues. However, effects of danger cues on mating interactions have
not been investigated. We exposed heterosexual pairs of Faxonius virilis
to conspecific alarm cues in the mating season and compared their
interactions with those of unexposed pairs. We found that almost all
crayfish in both groups mated within the experimental period, but latency
to begin mating varied with treatment and body size. Specifically, in the
exposed group, small pairs showed increased latency to begin mating
relative to larger pairs, while crayfish in the unexposed group showed the
opposite pattern. Thus, crayfish responses to danger cues may be a
function of their perceived risk based on body size, as smaller crayfish
are likely to be more vulnerable to predators. We propose that, under
natural conditions including the presence of mate competition, an
increased latency to begin mating is likely to result in decreased mating
success for smaller crayfish in the presence of danger cues. Such
behavioral NCEs may result in differential selection on body size in
environments with different predator pressure with consequent effects on
crayfish populations and aquatic communities.