Research interests

• Behavioral and sensory ecology
• Communication and cognition
• Social and vocal learning

 

 

 

 

 

 

 

Scientific projects

The main emphasis of my research is animal communication, especially the information content, social function and development of acoustic signals. I work with bats because as study organisms they offer a unique combination of high ecological diversity, complex social systems and enormous vocal flexibility.

Current scientific projects include:

Social and vocal complexity in Emballonurid bats
According to the Machiavellian intelligence hypothesis, the driving force in the evolution of primate intelligence is social expertise, which enables the manipulation of and cooperation with other social group members (Whiten & Byrne 1988, Whiten 1999). Social interactions require communication and interspecific differences in social complexity may explain the observed variation of vocal repertoire complexity in different species. While this proposition apparently applies to primates (Dunbar 1993), little evidence has been found so far in bats (Wilkinson 2003). This could be due to the lack of comparative studies incorporating both behavioral observations on indicators of social complexity (e.g., behavioral repertoire size, group size, composition, and stability) and genetic analyses to assess the impact of sexual selection on social complexity and, accordingly, vocal complexity. We will try to fill this gap by testing the influence of social complexity on vocal complexity in six species of Emballonurid bats (Saccopteryx bilineata, S. leptura, Rhynchonycteris naso, Balantiopteryx plicata, Cormura brevirostris, and Peropteryx kappleri).

Local dialects in territorial songs of Saccopteryx bilineata
Geographic variation in the structure and complexity of vocalizations has been widely reported for birds and, to a lesser extend, for pinnipeds, cetaceans, primates and bats (Janik & Slater 1997, Boughman & Moss 2003). Geographic variation of vocalizations is often caused by vocal learning but this relation is not mandatory. In bats, there is currently no evidence for geographic variation of vocalizations through vocal learning. Pups of the greater sac-winged bat Saccopteryx bilineata learn an adult vocalization type, the territorial song, through the imitation of tutors (Knörnschild et al. 2009). We are investigating whether territorial songs differ between various populations in Costa Rica. We will map the acoustic distance in signal space (i.e., difference between territorial songs from different populations) onto the genetic and geographic distance in order to determine whether acoustic differences between populations (Davidson & Wilkinson 2002) are caused by genetic and/or geographic isolation or by vocal learning.

Syntax in courtship songs and babbling bouts of Saccopteryx bilineata
Syntax is a set of rules for assembling units of any type into a larger unit, e.g. the temporal arrangements of acoustic units within song (Marler 1977). As a prerequisite for using combinatorics (“making infinite use of finite means''), the advantages of syntax are best illustrated in the vast expressive power of human language (Chomsky 1965, Jackendoff 1997). Hence, the transition from non-syntactic to syntactic communication was a keystone in the evolution of human language (Nowack 1999; Hauser et al. 2002, Fitch 2005) because syntax allows larger repertoires and the possibility to formulate new messages (Nowak et al. 2000). At least in birds (Balaban 1988, Honda & Okanoya 1999), the complexity and diversity of song syntaxes can evolve through sexual selection if females prefer complex songs. In bats, little evidence for syntax exists (Kanwal et al. 1994, Esser et al. 1997), even though syntax is probably fairly widespread, especially in species with complex vocal repertoires. Two vocalization types of the greater sac-winged bat Saccopteryx bilineata are well suited for studying syntax in bats: (1) Male S. bilineata produce long and complex courtship songs consisting of various distinct syllables. We want to investigate the structural rules underlying courtship songs, i.e. determining whether the sequence of syllables in courtship songs is defined through syntax or random improvisation. (2) S. bilineata pups produce long babbling bouts during the acquisition of the vocal repertoire. In these babbling bouts, adult vocalization types are combined into supposedly meaningless strings of vocalizations (Knörnschild et al. 2006). We will investigate whether babbling is defined by syntactical rules and whether these rules change as babbling bouts become more complex throughout the pups’ ontogeny.

For more information see http://sites.google.com/site/mknoernschild/

Publications

Eckenweber M, Knörnschild M (2013) Social influences on territorial signalling in male greater-sac winged bats. Behavioural Ecology and Sociobiology 67:639-648

Nagy M, Günther L, Knörnschild M, Mayer F (2013) Female-biased dispersal in a bat with a female-defence mating strategy. Molecular Ecology 22:1733-1745

Nyffeler M, Knörnschild M (2013) Bat predation by spiders. PLOS ONE 8:e58120

Knörnschild M, Nagy M, Metz M, Mayer F, von Helversen O (2012) Learned vocal group signatures in the polygynous bat Saccopteryx bilineata. Animal Behaviour 84:761-769

Knörnschild M, Tschapka M (2012) Predator mobbing behaviour in the Greater Spear-Nosed Bat, Phyllostomus hastatus. Chiroptera Neotropical 18:1132-1135

Gonzalez-Terrazas TP, Medellin R, Knörnschild M, Tschapka M (2012) Morphological specialization influences nectar extraction efficiency of sympatric nectar-feeding bats. J Exp Biol 215:3989-3996

Knörnschild M, Jung K, Nagy M, Metz M, Kalko EKV (2012) Bat echolocation calls facilitate social communication. Proc R Soc B 279:4827-4835

Nagy M, Knörnschild M, Voigt CC, Mayer F (2012) Male greater sac-winged bats gain direct fitness benefits when roosting in multimale colonies. Behavioral Ecology 23:597-606

Fulmer AG, Knörnschild M (2011) Intracolonial social distance, signaling modality and association choice in the greater sac-winged bat (Saccopteryx bilineata). J Ethol 30:117-124

Knörnschild M, Ueberschaer K, Helbig M, Kalko EKV (2011) Sexually selected infanticide in a polygynous bat. PLoS ONE 6:e25001

Knörnschild M, Fulmer AG, von Helversen O (2010) Duration of courtship displays correspond to social status in male greater sac-winged bats (Saccopteryx bilineata). Can J Zool 88:589-594

Knörnschild M, Glöckner V, von Helversen O (2010) The vocal repertoire of two sympatric species of nectar-feeding bats (Glossophaga soricina and G . commissarisi). Acta Chiropterologica 12:205-215

Strauss M, von Helversen O, Knörnschild M (2010) The ontogeny of courtship behaviours in bat pups (Saccopteryx bilineata). Behaviour 147:661-676

Knörnschild M, Nagy M, Metz M, Mayer F, von Helversen O (2010) Complex vocal imitation during ontogeny in a bat. Biology Letters 6:156-159

Knörnschild M, Harview C, Moseley R, von Helversen O (2009) Remaining cryptic during motion - behavioral synchrony in the proboscis bat, Rhynchonycteris naso. Acta Chiropterologica 11(1):208-211

Behr O, Knörnschild M, von Helversen O (2009) Territorial counter-singing in male sac-winged bats (Saccopteryx bilineata): low frequency songs trigger a stronger response. Behavioral Ecology and Sociobiology 63:433-442

Voigt C, Behr O, Caspers B, von Helversen O, Knörnschild M, Mayer F, Nagy M (2008) Songs, scents, and senses: Sexual selection in the greater sac-winged bat, Saccopteryx bilineata. Journal of Mammalogy 89:1401-1410

Knörnschild M, von Helversen O (2008) Non-mutual vocal mother-pup recognition in the sac-winged bat, Saccopteryx bilineata. Animal Behaviour 76(3):1001-1009

Knörnschild M, von Helversen O, Mayer F (2007) Twin siblings sound alike – isolation call variation in the Noctule bat, Nyctalus noctula. Animal Behaviour 74(4):1055-1063

Knörnschild M, Behr O, von Helversen O (2006) Babbling behavior in the sac-winged bat (Saccopteryx bilineata). Naturwissenschaften 93(9):451-455

Knörnschild M, Nagy M, Metz M, Mayer F, von Helversen O (2012) Learned vocal group signatures in the polygynous bat Saccopteryx bilineata. Animal Behaviour 84:761-769

Conference contributions

Mumm C, Urrutia MC, Knörnschild M (2013) Vocal individuality in cohesion calls of giant otters (Pteronura brasiliensis). Poster presented at the Conference of the Society for Tropical Ecology (gtö), Vienna, April 2-5, 2013

Geipel I, Kalko EKV, Wallmeyer K, Knörnschild M (2013) Hey Mom, what’s for dinner? Parental food provisioning in a bat with a complex hunting strategy. Talk presented at the Workgroup Meeting of German bat Researchers, Rottenburg-Ergenzingen, Germany, 11.-13.01.2013

Mumm CAS, Chunga AML, Tschapka M, Knörnschild M (2012) Avances del estudio "El repertorio vocal de los lobos de río (Pteronura brasiliensis). Talk presented at the III Congreso de la Sociedad Peruana de Mastozoología, Píura, Peru, 14.-18.Okt. 2012

Gonzalez-Terrazas TP, Medellín RA, Knörnschild M, Tschapka M (2012) Morphological specialization influences nectar extraction efficiency of sympatric nectar-feeding bats. Poster presented at the Annual Conference of the Society for Tropical Ecology (gtö), Erlangen, Germany, February 22 – 25, 2012

Geipel I, Kalko E, Knörnschild M (2012) Hey Mom, what’s for dinner? Parental food provisioning in bats with a complex hunting strategy. Talk presented at the VIth European Conference on Behavioural Biology, ECBB, Essen, Germany, 19 - 22 July

Knörnschild M, Nagy M, von Helversen O (2010) Learned vocal group signatures in a polygynous bat. 15th International Bat Research Conference (IBRC), Prague, Czech Republic.

Knörnschild M, Nagy M (2010) Learned vocal group signatures in the bat Saccopteryx bilineata. Communication Meeting, Berlin, Deutschland.

Knörnschild M, Nagy M, Helversen Ov (2010) Vocal learning in a bat - the case study Saccopteryx bilineata. 84th Annual Meeting of the German-Society-of-Mammalogy, Berlin, GERMANY, September 12 -16, 201

Knörnschild M, Nagy M, von Helversen O. 2009. Vocal learning in a bat (poster). 1. Joint Meeting of ATBC (Association of Tropical Biology and Conservation) and GTÖ (Society for Tropical Ecology), Marburg, Germany.

Knörnschild M, Nagy M, von Helversen O. 2008. Vocal repertoire ontogeny in the bat Saccopteryx bilineata – evidence for vocal learning. 2. Acoustic Communication by Animals Conference, Corvallis, USA.

Knörnschild M, von Helversen O. 2007. Isolation calls and their role during vocal repertoire ontogeny in the greater sac-winged bat, Saccopteryx bilineata. 14. International Bat Research Conference (IBRC) and 37. North American Symposium on Bat Research (NASBR). Merída, Mexico.

Knörnschild M, von Helversen O. 2007. Emotional prosody in social vocalizations of the greater sac-winged bat, Saccopteryx bilineata. International Symposium on the Evolution of Emotional Communication (EEC), Hannover, Germany.

Knörnschild M, von Helversen O. 2007. When twins sound alike – isolation call variation in the Noctule Bat, Nyctalus noctula. Graduate Meeting of the DZG Group Behavioural Ecology, Göttingen, Germany.

Knörnschild M, Nagy M, Helversen Ov (2010) Learned vocal signatures in a polygynous bat. 15th International Bat Research Conference, 23.-27. August 2010, Prague, Czech Republic

Knörnschild M (2011) Vocal signatures in Saccopteryx bilineata - Insights from a vocal learning bat. XXIII Meeting of the International Bioacoustics Council (IBAC), La Rochelle, France.

Knörnschild M, Jung K, Kalko EKV (2011) Communication on the wing: vocal signatures in echolocation calls of the greater sac-winged bat. 3rd Symposium on Acoustic Communication by Animals, Cornell University, Ithaca, USA.

Knörnschild M, Behler C, Tschapka M (2011) Vocal communication in Glossophaga soricin - Alert calls and territoriality. German Bat Researcher Meeting, Loccum, Germany.

Mumm CAS, Urrutia C, Chunga AML, Tschapka M, Knörnschild M (2012) Avances del estudio "Comunicación acústica de los lobos de río (Pteronura brasiliensis) como herramienta de conservación natural. Talk presented at the Congreso Regional: Investigación y Monitoreo Biológico en Áreas Naturales Protegidas y Corredores de Conservación – Madre de Dios, Perú, 24 y 25 de Mayo - 2012