The night shift that helps fill durian trees
Camera traps on Tioman Island showed flying foxes visiting durian flowers without the damage they are often blamed for.
Flying foxes have been accused of damaging durian blossoms. A 2017 study in Ecology and Evolution by Sheema Aziz and colleagues set out to see what actually happens in the canopy.
From April to July 2015, the team worked in a durian orchard at Juara village on Tioman Island, off Peninsular Malaysia. They mounted paired infrared camera and video traps at 19 stations, from 2.4 to 20.3 metres above the ground, across four flowering trees. They gathered 2,733 video clips and 3,367 photographs.
At least nine animal species visited, but the paper found that only bats had a mutually beneficial relationship with the flowers. Nectar bats made up about 83% of vertebrate visits, with flying foxes and plantain squirrels at about 9% and 8%. Height mattered: above roughly six metres, flying foxes outnumbered nectar bats.
The flying foxes also seemed to be careful guests. Just 11 of 187 feeding interactions showed minor flower damage, whereas about 42% of squirrel detections involved biting flowers. Flying fox visits had a positive statistical link with mature fruit set, while nectar bat visits showed a slight negative one in this setting.
The authors argue that the island flying fox, locally endangered according to the paper's title, is worth more to people than previously recognised, which strengthens the case for conserving it. They also state the limits: four trees are a small sample, and the work needs repeating across more orchards and seasons.