mise à jour du
30 mai 2002
Behav Ecol Sociobiol 1999;47:29-40  
 Storage and display of odour by male
Saccopteryx bilineata (Chiroptera, Emballonuridae)
C.C. Voigt - 0. von Helversen
Institut für Zoologie, Universität Erlangen-Nürnberg, Erlangen, Germany


Abstract : Males of the sac-winged bat, Saccopteryx bilineata, actively fill their propatagial sacs with secretions from the genital region, the gular gland, urine and saliva. From our observations and those of Starck we deduce that propatagial sacs in S. bilineata do not have a glandular function, but are instead organs for the storage and display of odours.

In addition to the already known "salting" and hovering behaviour of male S. bilineata, we describe in detail how odour is fanned to roosting individuals during the complex, stereotypic hovering displays. S. bilineata males also coat the fur of their backs with saliva using the wing tip and might scent-mark territory boundaries.

"Yawning" may represent a visual as well as an olfactory cue. Odour seems to play an important role in the social communication of S. bilineata and in other emballonurids, as revealed by the broad distribution of wing sacs in this family. S. bilineata males display odour during energetically costly hovering flights in front of females. We demonstrate that the number of hovering displays increases with harem size. The mating effort of S. bilineata males comprises a multimodal signalling behaviour. ALThough males defend harem territories in which females gather, females seem to be able to choose the father of their progeny freely among the males of a colony. This may have led to the evolution of the complex mating displays by male S. bilineata. [....]


"Yawning" : Male Saccopteryx often "yawn" after or before agonistic interactions with other individuals. First they lowered their head and opened their mouth slowly, then both lips were lifted and turned up so that both rows of white teeth and the moist pale gum were exposed.


Yawning: an evolutionary perspective Smith EO

« It is ironic that testosterone "the male sex hormone," is more closely associated with the yawning rate than with the mounting or intromitting rates » Charles Phoenix
Sexual steroids exert several effects on both central dopaminergic and oxytocinergic systems by acting either at the genomic or membrane level  
credit photo : "Asif A. Ghazanfar and Aristides Arrenberg"
Max Planck Institute for Biological Cybernetics
Tuebingen; Germany.
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