Diadem roundleaf bats are predominantly insectivorous, feeding mostly on large insects, favouring beetles, grasshoppers and locusts, and moths (10) (11). This species is also carnivorous having been recorded feeding on birds at two sites in Australia (10). The main foraging method is perch hunting which is a low-energy strategy. Its prey commonly move with direct and predictable flight paths, making it possible for the bats to hang from a tree branch, up to ten metres above the ground, waiting for a suitable insect to fly past. Whilst at the perch, the bat scans the area using echolocation at a constant frequency of 58 to 60 kilohertz. Once it has detected an insect, it drops from its perch and flies fast and straight to snatch its quarry from the air. The size of the pup relative to the mother in insectivorous bats is remarkable. This species can give birth to a single pup weighing 13 grams – a quarter of its mother's weight. The mother must carry the pup on foraging trips until it is developed enough to fly and feed alone. By one year the young diadem roundleaf bat will be ready to breed (3).

An impressive sight amongst the trees of the rainforest, this large bat is a formidable hunter with a wingspan of up to half a metre. Readily identifiable by its pig-like face, the diadem roundleaf bat also possesses distinctive white flashes on the shoulders, contrasting with the reddish-brown back and light-brown underside. The colour varies quite strongly between individuals, and females are generally more orange. The noseleaf is pink and highly convoluted, but the ears are brown (3).

This widespread species ranges from the Nicobar Islands of India through Southeast Asia to Australia. On the Nicobar Islands, the endemic subspecies H. d. nicobarensis is present on the islands of Bompuka, Katchal, Tillangchong, Tressa and Trinket (Aul and Vijaykumar 2003). In Southeast Asia, it ranges from southern Myanmar, into Thailand, Cambodia, Viet Nam and southern Lao PDR, to Peninsular Malaysia, and from here to much of Indonesia (including the islands of Sumatra, Java, Bali and Sulawesi), East Timor, the island of Borneo (Brunei, Indonesia and Malaysia), and the Philippines. In the Philippines it is found in all regions (sea level to 900 m asl) except the Batanes/Babuyan region. Specimens have been collected from the Philippines islands of Bohol, Busuanga, Calauit, Catanduanes, Cebu (Lawrence, 1939), Dinagat, Guimaras, Leyte, Luzon [Benguet (Taylor, 1934), Bulacan, Cagayan, Camarines Sur, Ilocos Norte, Isabela, Laguna, Nueva Vizcaya, Pampanga, Quezon, Rizal (Taylor, 1934) provinces], Mindanao [Agusan del Norte, Bukidnon, Davao Oriental, Lanao del Norte, Maguindanao, South Cotabato (Sanborn, 1952), Zamboanga del Norte, Zamboanga del Sur (Taylor, 1934)], Mindoro (Lawrence, 1939), Negros, Palawan, Panay, Polillo, Samar, Siquijor (Heaney et al., 1998). There are some records from the island of Tawi-tawi (K. Helgen pers. comm.). On the island of New Guinea (Indonesia and Papua New Guinea) it is found in scattered localities and it is present throughout much of the Bismarck Archipelago (Papua New Guinea). The species has been recorded from the islands of Bougainville and Buka (Papua New Guinea), and from many of the Solomon Islands. It is present in Australia where it is largely restricted to the rainforests of northern Queensland (Corbet and Hill 1992; Flannery 1995; Strahan 1995; Bonaccorso 1998). It is found from sea level to 1,300 m asl.

The Malayan leaf-nosed bat is the most widespread of the subfamily Hipposiderinae. It ranges from northern Australia to New Guinea and southeastern Asia. This includes the Nicobar Islands, Indonesia, southern Burma and Thailand, Philippines, Timor, Solomon Islands, northeastern Queensland, Sunda Islands, Indochina, the Malay Peninsula, Sumatra, Java, and the Kangean Islands (Nowak, 1999; Kitchener, 1992).

Biogeographic Regions: oriental (Native )

This species is widespread, occurring from Southeast Asia to North Queensland, Australia. It has many subspecies; Hipposideros diadema anderseni (Philippines), H. d. ceramensis (Moluccas), H. d. custos (Kei Islands), H. d. enganus (Sumatra) (5), H. d. inornatus (Northern Territory, Australia) (2), H. d. masoni (Borneo) (6), H. d. natuensis (Natuna Islands and Bunguran Island), H. d. reginae (North Queensland, Australia) (2), and H. d. speculator (Sulawesi) (5).

These bats are named for their complex anterior nose leaf, which is horseshoe-shaped and located on the slightly inflated nasal region. This nose shape evolved to assist in echolocation, adding the noseleaf and the associated intricate musculature to help the nose resonate more effectively (Gobbel, 2002). The transverse leaf is erect, and in contrast to the nose leaf of other rhinolopids, there is no median projection (sella)(Feldhamer, 1999). They have huge ears mainly because of the well-developed antitragus, while no tragus is present (DeBlase, 1991). Males have a sac located posterior to the nose which can secrete a waxy substance, thought to be used in attracting mates and status determination. Body length ranges from six to ten centimeters when adult, with brown fur covering all but the limbs. The underbelly is paler in color, and white spots can be found in the shoulder region. Adults weigh between 34 and 50 grams, and the wingspan is approximately 15 to 22 cm. Hefty claws are found on the hind limbs, and a single claw on each of the forelimbs (Nowak, 1999). Each toe of the foot has two phalanges, and the short tail is usually enclosed within the small uropatagium (Feldhamer, 1999). The dental formula is 1/2 1/1 2/2 3/3, molars are dilambdodont, and hefty enamel tubules are present at dentin-enamel junctions (Lester, 1987). The oral region of the skull exhibits premaxillary palatal branches that are fused medially, and widely separated from the maxillae laterally (spatulate) (DeBlase, 1981).

Range mass: 34 to 50 g.

Range length: 6 to 10 cm.

Range wingspan: 15 to 22 cm.

Other Physical Features: endothermic ; bilateral symmetry

Habitat and Ecology

Systems

• Terrestrial

These bats typically roost in large caves, hollow trees and buildings (Nowak, 1999). In Australia, they prefer tall limestone towers within which thousands of these bats congregate (Fenton, 1982). They typically forage along rivers in forested habitats.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest

With a heavy body and long, narrow wings, the diadem roundleaf bat is adept at fast flight but has relatively poor manoeuvring ability. It has adapted to foraging in gaps in forests, such as around tree falls or above rivers. This bat species is not restricted to rainforest and in outback Australia it forages within eucalypt woodland and open forest, deciduous vine thicket and within towns (7). Individuals are known to forage up to two and a half kilometres from the roost during the course of the night (7). During the day it roosts in small groups in caves, old mines and sheds, hollow trees and tree branches (8) (9).

These bats are usually insectivorous (Feldhamer, 1999). The diet varies depending on specific location, but they tend to prefer insects such as coleopterans (beetles), lepidoterans (butterflies and moths), and those within the orthopteroid (grasshoppers) orders. However, they will prey on small birds and spiders, albeit rarely. Thus, H. diadema is sometimes classified as an 'occasional carnivore' (Pavey, 1997).

These bats are extremely adept predators. By using echolocation, intensified through their highly modified nose and nostrils, they achieve very high rates of success (Gobbel, 2002). A constant frequency call is emitted around 50 to 58 kilohertz, and maintained for 20 to 30 seconds at a time (Jen, 1982; Fenton, 1982). They are not continuous flight hunters; instead, they prefer to take short flights from their perches and intercept the prey in midair (Pavey, 1998). When hunting, they usually fly over a stream or creek that is covered in canopy. They very rarely venture out over open water (Fenton, 1982). Lepidopterans (eared moths) make up a significant portion of their diet, and these insects have an auditory range from 20 to 50 kHz. Research has shown that these insects can sense the echolocation pulses and have learned to evade or hide from the attacking bats (Pavey, 1998).

Animal Foods: birds; insects; terrestrial non-insect arthropods

Primary Diet: carnivore (Insectivore )

These bats are vital in controlling insect populations within natural communities. Their feces are also very nutritive and help fertilize plant flora (Nowak, 1999).

These bats are probably preyed on by large, nocturnal birds of prey, such as owls and in roosts by snakes and small mammalian carnivores, such as Malayan civets (Viverra tangalunga).

Known Predators:

• owls (Strigiformes)
• snakes (Serpentes)
• civets (Viverridae)

Hipposideros diadema is prey of:
Strigiformes
Serpentes
Viverridae

This list may not be complete but is based on published studies.

Hipposideros diadema preys on:
Arthropoda
Insecta
Aves

This list may not be complete but is based on published studies.

The large Malayan leaf-nosed bat typically lives between four and seven years in the wild, but can live up to twelve in captivity (Nowak, 1999).

Range lifespan

Status: captivity: 12 (high) years.

Typical lifespan

Status: wild: 7 (high) years.

One breeding season exists, and birthing and lactation coincide with the maximum quantity of insects in the spring. One young is born per litter. Male competition involves some physical skirmishes, but mainly the secretion and detection of a waxy material from behind the nose (Feldhamer, 1999). Interestingly, females congregate in large groups during March and April, during which each one gives birth to a single offspring (Nowak, 1999). The mother remains intimate with the young until weaning, when the juvenile usually becomes independent.

The following is a representative barcode sequence, the centroid of all available sequences for this species. 

 
There are 15 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
 

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 15
Species: 20
Species With Barcodes: 1

The Malayan leaf-nosed bat is not currently endangered or threatened. It was listed as "lower risk - least concern" on the 1996 RedList, but has since been removed from that list.

US Migratory Bird Act: no special status

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

Classified as Lower Risk / Least Concern (LR/lc) on the IUCN Red List 2007 (1).

Population

Population Trend

Major Threats

Habitat loss and degradation is the biggest problem facing the diadem roundleaf bat. Deforestation continues at a steady rate for conversion to agricultural land and building communities. Of particular concern is the extensive loss of primary forest due to the rapid increase in land devoted to growing oil palm. Together, Malaysia and Indonesia export 88 percent of the world's palm oil, for use in products such as margarine, lipstick and detergent (13). Disturbance of roost sites is also an issue (7), and despite the contribution of many bats in the control of insect crop pests, persecution of bats is also a threat (12).

Conservation Actions

Deforestation of primary forest, especially for oil palm plantations, and in particular within protected areas, is an issue of major concern and one that relies on both governmental and consumer action. Some large retailers have agreed, in collaboration with the World Wildlife Fund (WWF), to source products containing palm oil from plantations that are not on deforested land (12). Many scientific and charitable groups contribute to bat monitoring and local education programmes that can help to reduce persecution and raise awareness of the natural assets of the land (14).

It is extremely rare, only when harassed or cornered, but these bats can have a painful bite, and they carry a myriad of parasites, most of which have no effect on humans (Uchikawa, 1983).

Insect populations are kept in check by these bats, and some locals use the dung for fertilizer (Nowak, 1999; Pavey, 1998).

Positive Impacts: produces fertilizer; controls pest population