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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Approach to fig (F. colubrinii) by E. alba with landing

Audio Audio observationobservation

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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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