A closer look at Cave Nectar Bats visiting banana flowers

on 7th February 2015

Two earlier posts documented the visits by Cave Nectar Bats (Eonycteris spelaea) to banana flowers (Musa cultivars) for their nectar LINK 1 and LINK 2.

The bat usually circles around the plant before landing on the flowers. It uses its sharp claw at the end of each thumb to cling onto the inflorescence bud.

It then proceeds to probe into the flowers (above). This involves pushing its narrow snout between the two perianths (the larger upper and the smaller lower to get at the nectar – see below.

It uses its long red tongue to lick up the nectar (below). And it knows exactly which flowers to probe and which to ignore.

In this post we specifically look at the frequency of visits and the number of male flowers probed for their nectar during each visit. Visits usually come between 2200 hours onwards at intervals of 30 to 60 minutes or so.

Observations were made when the banana inflorescence was at the male-flowers stage (see HERE for detaiis) and actively producing male flowers. During each visit, the bat sometimes systematically probed the flowers from one end to the other, starting with the upper row and ending with the lower. At other times it selectively probed the flowers, possibly targeting only those with sufficient nectar.

On the night of 15th January 2015, between 2130-0100 hours, two visits were recorded (video below) – it is not known whether the visits were by the same bat or different bats. The first visit took 32 seconds and the bat probed 18 male flowers for their nectar – note that there were about 18-19 flowers per hand. The second visit, about a hour later, lasted 25 seconds when 13 flowers were probed.

On the night of 18th January, between 2130-2300 hours, there were three visits. The last visit lasted five seconds and the bat probed only two flowers for their nectar (video below). This is compared to the earlier two visits when it spent 20-25 seconds probing 13-15 flowers.

Obviously after each visit the flowers will have less nectar left. Revisiting the flowers after 30-60 minutes will allow them to replenish their supply.

YC Wee
February 2015

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

Other posts by YC Wee

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