Common name: The Diadem Roundleaf Bat
Nose: Like all roundleaf bats Hipposideros diadema has a very distinctive noseleaf, which in this case is large and pinkish brown. But only a few Hipposideros species have lateral leaflets, small crescents of skin, on the muzzle either side of the noseleaf. In Hipposideros diadema there are 3 – 4 lateral leaflets.
Fur: Overall, the fur on the head and back is brown, but this species has a very distinctive creamy-white flash on the shoulders, which then continues as a stripe running down the sides of the body. The brown fur on the back is is actually made up of individual hairs that have three bands of color, brown at the base, then a whitish cream and then brown again at the tips. In older females there is often an orange tinge to fur. The fur on the face and undersides is a lightish grey brown, and you can just see a darker stripe running down from the top of the head.
Wings: Like the ears, the wings are brown, and and very large and broad.
Size: Hipposideros diadema is the biggest insectivorous bat that we catch in the understorey at Krau, with an average forearm of 84 mm and an average weight of 44g.
Hipposideros diadema is common in both primary and secondary forest at all elevations and is mainly a cave dweller. It often roosts in large groups in caves, but smaller colonies will use the crevices of large boulders. Occasionally, individuals will roost on their own under palms, or under leaves in the midstorey of the forest.
It forages primarily by perch hunting in gaps in the midstorey or over trails, waiting for slow-flying insects to pass beneath, which it will then swoop out and catch before returning to its perch to eat them. In Australia, its diet is primarily beetles, moths, and orthopterans (grasshoppers, crickets, etc), and occasionally, birds. In Malaysia, its diet also includes termites during swarming periods.
Radiotracking of a single male in Krau Wildlife Reserve found that the bat rotated through several perches in a night, all within approximately a 1 km2 area and at the end of the night, the bat roosted alone for the day at or near the last feeding perch.
Where they can be found
Myanmar and Vietnam through Thailand, Laos, Peninsular Malaysia, and Indonesia and New Guinea, Bismark Arch., Solomon Islands and NE Australia, Philippines, and Nicobar Islands.