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Feeding behaviourFeeding behaviour ofofEctophylla albaEctophylla alba on on Ficus Ficus
colubriniicolubrinii
Michael Reiser, Verena Rieger, Tanja WeisMichael Reiser, Verena Rieger, Tanja Weis
IntroductionIntroductionFrugivorous bats have to find their food in
highly cluttered space
Use of echolocation calls mainly for orientation, not detection, localization and classification of fruits
Detection by other senses like olfaction, visual information, sense of touch
FicusFicus and and the batsthe bats
• Important role of trees of the genus Ficus for frugivorous bats: constant fruit source
• Most bats related to Ficus feed on a specific group of figs (Kalko et al, 1996)
Ficus colubriniiFicus colubrinii• Ripe figs are red adapted to
mostly visual orientated seed dispersers (Tucan, Crested Guan, Coati)
• But: In the night also visited by Ectophylla alba
Ectophylla albaEctophylla alba• Hondurian White Bat • White fur, yellow noseleaf and
ears• Tent-Making Bat: roosts in
modified leafs during the day• Feeding behaviour: frugivorous• Details mostly unknown
QuestionQuestion
How does Ectophylla albadetect and localize ripe Ficus colubrinii figs ?
HypothesisHypothesis
Ectophylla alba detects and classifies ripe figs by olfactory cues
Ectophylla alba uses in addition echolocation to localize fruits in highly cluttered space
Material & Material & MethodsMethods• Study site: La Selva, Costa Rica• Catching Ectophylla alba with mist nets in
front of Ficus colubrinii• Collecting morphological parameters of the
bats
Material & Material & MethodsMethods
• Feeding tests in a flight cage by offering figs on a twig
• Audio and video recording
VideoVideo observation observation
– Ectophylla alba mostly feeds on ripe, red fruit
– Searching for fruits accompanied with moving noseleaf
– Ripe fruits are distinguished by touching the fruits or biting into them
– Bats approach petridishes filled with ripe figs
AudioAudio observationobservation
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0.1 0.2
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1.0 1.1 s
Approach to fig (F. colubrinii) by E. alba with landing
Audio Audio observationobservation
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0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20
Zeit [s]
Laut
abst
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Landing
• Evaluation of a single sequence showing approachand landing of Ectophylla alba
• Pulse intervals decrease• Calls are grouped
DiscussionDiscussion• Detection of ripe figs works mainly with
olfactory cues
• Moving nose leaf could be a hint for the use of echolocation and/or olfactory cuesto localize food
• Classification of ripe figs is done by testing their consistence; the direction of odour can probably not be specified clearly
DiscussionDiscussion
• Ectophylla alba uses short, high-frequent signals, which are useful in highly cluttered space because of their high resolution
• The final approach phase supplies detailed information to distinguish between the twigs and the figs
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