Mimicry in motion and morphology: do information limitation, trade-offs or compensation relax selection for mimetic accuracy?

Many animals mimic dangerous or undesirable prey as a defence from
predators. We would expect predators to reliably and exclusively avoid
animals that closely resemble dangerous prey, yet imperfect mimics are
common. There have been many hypotheses suggested to explain imperfect
mimicry, but comparative tests across multiple mimicry systems are needed
to determine which are applicable, and which—if any—represent general
principles of imperfect mimicry. We tested four hypotheses on Australian
ant mimics and found support for only one of them: the information
limitation hypothesis. A predator with incomplete information will be
unable to discriminate some poor mimics from their models. We also show
that since predators must make decisions while they are learning, they are
likely to never sample broadly enough to gain and utilise the full
information needed to discriminate poor mimics from their models. We found
no evidence that one accurate mimetic trait can compensate for another, or
that rapid movement reduces selection pressure for good mimicry. Based on
our results, we argue that information limitation is likely to be a
general principle behind imperfect mimicry of any complex traits, while
interactions between components of mimicry may apply to some mimicry
systems but not others.