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Schlagwörter:
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Zusammenfassung:
Animals employ an array of signals (i.e. visual, acoustic, olfactory) for communication. Natural selection favours signals,
receptors, and signalling behaviour that optimise the received signal relative to background noise. When the signal is used
for more than one function, antagonisms amongst the different signalling functions may constrain the optimisation of the
signal for any one function. Sexual selection through mate choice can strongly modify the effects of natural selection on
signalling systems ultimately causing maladaptive signals to evolve. Echolocating bats represent a fascinating group in
which to study the evolution of signalling systems as unlike bird songs or frog calls, echolocation has a dual role in foraging
and communication. The function of bat echolocation is to generate echoes that the calling bat uses for orientation and
food detection with call characteristics being directly related to the exploitation of particular ecological niches. Therefore, it
is commonly assumed that echolocation has been shaped by ecology via natural selection. Here we demonstrate for the
first time using a novel combined behavioural, ecological and genetic approach that in a bat species, Rhinolophus mehelyi:
(1) echolocation peak frequency is an honest signal of body size; (2) females preferentially select males with high frequency
calls during the mating season; (3) high frequency males sire more off-spring, providing evidence that echolocation calls
may play a role in female mate choice. Our data refute the sole role of ecology in the evolution of echolocation and
highlight the antagonistic interplay between natural and sexual selection in shaping acoustic signals.
