Field Frame Friday: A Sunrise Serenade with Song and Smells

Many bat species sing complex ultrasonic songs to attract mates and repel rivals [1]. An extremely eloquent singer is the neotropical great sac-winged bat (Saccopteryx bilineata). Males of this bat species sing year round during dusk and dawn, but singing is most intense during the annual mating season [2]. Then, harem males will sing for up to one hour to one particular female in their day-roost territory before moving on to the next one. During singing, the male performs hover displays in front of the courted female and fans an odiferous perfume her way [3]. Such a hover display is depicted in the multi-frame picture taken in Costa Rica (photo credit: Michael Stifter). It shows a roosting female being courted by a male on the wing. The male is first singing and then opening sacs on his wings (hence the name sac-winged bat) to release the perfume.

Young bats learn their song by imitating adult tutor males, just like young songbirds do [4,5]. Accumulated learning errors result in regionally different song dialects. Female sac-winged bats have a strong preference for their own regional dialect [6], suggesting that dialects may represent dispersal barriers that limit gene flow.

[Photo by Michael Stifter and caption by Mirjam Knörnschild]

[1] Smotherman M, Knörnschild M, Smarsh G, Bohn KM (2016) The origins and diversity of bat songs. Journal of Comparative Physiology A 202(8): 535-554.

[2] Behr O & von Helversen O (2004) Bat serenades – complex courtship songs of the sac-winged bat (Saccopteryx bilineata). Behavioral Ecology and Sociobiology 56, 106–115.

[3] 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(6): 1401-1410.

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

[5] Knörnschild M, Nagy M, Metz M, Mayer F, von Helversen O (2010) Complex vocal imitation during ontogeny in a bat. Biology Letters 6(2): 156-159.

[6] Knörnschild M, Blüml S, Steidl P, Eckenweber E, Nagy M (2017) Bat songs as acoustic beacons – male territorial songs attract dispersing females. Scientific Reports 7: 13918.

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