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Hipposideros diademadiadem roundleaf bat

By Barbara Lundrigan and Steve Baker

Geographic Range

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).

Habitat

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.

Physical Description

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
    1.20 to 1.76 oz
  • Range length
    6 to 10 cm
    2.36 to 3.94 in
  • Range wingspan
    15 to 22 cm
    5.91 to 8.66 in

Reproduction

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.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual

Lifespan/Longevity

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

Behavior

These bats are nocturnal and gregarious. They congregate and live in groups that can be as large as two to three thousand individuals. Not on an individual level, but as a colony, there seems to be some territoriality exhibited (Nowak, 1999).

Communication and Perception

Food Habits

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

Predation

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).

Ecosystem Roles

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

Economic Importance for Humans: Positive

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

Economic Importance for Humans: Negative

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).

Conservation Status

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.

Other Comments

There has been some controversy over the classification of the hipposiderid bats. Koopman (1993) and the majority of others have the subfamily Hipposiderinae listed under the family Rhinolophidae (Feldhamer, 1999). However, Hill and Smith (1984) and several others classify Hipposideridae as a separate family from the rhinolophid horseshoe bats (Eisentraut, 1975).

Contributors

Barbara Lundrigan (author), Michigan State University, Steve Baker (author), Michigan State University.

Glossary

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

References

DeBlase, A., R. Martin. 1981. A Manual of Mammalogy. New York: McGraw-Hill.

Eisentraut, M. 1975. Animal life encyclopedia. New York: Van Nostrand Reinhold.

Feldhamer, G., L. Drickamer, S. Vessey, J. Merritt. 1999. Mammalogy. New York: McGraw-Hill.

Fenton, M. 1982. Echolocation calls and patterns of hunting and habitat use of bats (Microchiroptera) from Chillagoe, North Queensland, Australia. Australian Journal of Zoology, (30)3: 417-426.

Gobbel, L. 2002. Morphology of the external nose in *Hipposideros diadema* and *Lavia frons* with comments on its diversity and evolution among leaf-nosed microchiroptera. Cells Tissues Organs, 170(1): 36-60.

Jen, P., R. Suthers. 1982. Responses of inferior collicular neurons to acoustic stimuli in certain frequency modulation and constant frequency-frequency modulation paleotropical bats. Journal of Comparative Physiology, 146(4): 423-434.

Kitchener, D., R. How, N. Cooper, A. Suyanto. 1992. *Hipposideros diadema* (Chiroptera Hipposideridae) in the lesser Sunda Islands, Indonesia: taxonomy and geographic morphological variation. Records of the Western Australian Museum, 16(1): 1-60.

Lester, K., S. Hand. 1987. Chiropteran enamel structure. Journal of Scanning Microscopy, 1(1): 421-436.

Nowak, R. 1999. Walker's Mammals of the World. Baltimore, Maryland: Johns Hopkins University Press.

Pavey, C. 1998. Bat predation on eared moths: a test of the allotonic frequency hypothesis. OIKOS, 81(1): 143-151.

Pavey, C. 1998. Colony sizes, roost use and foraging ecology of *Hipposideros diadema* reginae, a rare bat from tropical Australia. Pacific Conservation Biology, 4(3): 232-239.

Pavey, C., C. Burwell. Oct. 1997. The diet of the diadem leaf-nosed bat, *Hipposideros diadema*: confirmation of a morphologically-based prediction of carnivory. Journal of Zoology, 243(2): 295-303.

Uchikawa, K., M. Harada, S. Yenbutra, S. Ohtani. 1983. Bat myobiidae from Thailand (Acari, Trombidiformes). Acarologia, 24(2): 169-180.

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