Many mating signals consist of multimodal components that need decoding by several sensory modalities on the receiver’s side. For methodological and conceptual reasons, the communicative functions... Show moreMany mating signals consist of multimodal components that need decoding by several sensory modalities on the receiver’s side. For methodological and conceptual reasons, the communicative functions of these signals are often investigated only one at a time. Likewise, variation of single signal traits are frequently correlated by researchers with senders’ quality or receivers’ behavioural responses. Consequently, the two classic and still dominating hypotheses regarding the communicative meaning of multimodal mating signals postulate that different components either serve as back-up messages or provide multiple meanings. Here we discuss how this conceptual dichotomy might have hampered a more integrative, perception encompassing understanding of multimodal communication: neither the multiple message nor the back-up signal hypotheses address the possibility that multimodal signals are integrated neurally into one percept. Therefore when studying multimodal mating signals, we should be aware that multimodal signals can give rise to multimodal percepts, meaning that receivers can gain access to additional information inherent to only combined signal components (‘the whole is something different than the sum of its parts’). We review the evidence for the importance of multimodal percepts and outline potential avenues for discovery of multimodal percepts in animal communication. Show less
Birdsong is a sexually selected trait that could play an important evolutionary role when related taxa come into secondary contact. Many songbird species, however, learn their songs through copying... Show moreBirdsong is a sexually selected trait that could play an important evolutionary role when related taxa come into secondary contact. Many songbird species, however, learn their songs through copying one or more tutors, which complicates the evolutionary outcome of such contact. Two subspecies of a presumed vocal learner, the grey-breasted wood-wren (Henicorhina leucophrys), replace each other altitudinally across the western slope of the Ecuadorian Andes. These subspecies are morphologically very similar, but show striking differences in their song. We examined variation in acoustic traits and genetic composition across the altitudinal range covered by both subspecies and between two allopatric populations. The acoustic boundary between the subspecies was found to be highly abrupt across a narrow elevational range with virtually no evidence of song convergence. Mixed singing and use of hetero-subspecific song occurred in the contact zone and was biased towards the use of leucophrys song types. Hetero-subspecific song copying by hilaris and not by leucophrys reflected a previously found asymmetric pattern of response to song playback. Using amplified fragment length polymorphisms (AFLP) markers, we detected hybridization in the contact zone and asymmetric introgression in parapatric populations, with more leucophrys alleles present in hilaris populations than vice versa. This pattern may be a trail of introgression due to upslope displacement of leucophrys by hilaris. Our data suggest that song learning may impact speciation and hybridization in contrasting ways at different spatial scales: although learning may speed up population divergence in songs, thereby enhancing assortative mating and reducing gene flow, it may at a local level also lead to the copying of heterospecific songs, therefore allowing some level of hybridization and introgression. Show less
The acoustic courtship display of a male and a female great tit show all the characteristics of a passionate dance. This thesis examines the impact of anthropogenic noise on the acoustic... Show moreThe acoustic courtship display of a male and a female great tit show all the characteristics of a passionate dance. This thesis examines the impact of anthropogenic noise on the acoustic communication between males and females and the relationship with reproduction. Show less
Halfwerk, W.; Bot, S.; Buikx, J.; Velde, M. van der; Komdeur, J.; Ten Cate, C.; Slabbekoorn, H.W. 2012
