Pteropus alecto

Geographic Range

Pteropus alecto is found in the Australian and Oriental regions of the world. It is found from tropical/subtropical Australia to Sulawesi (from 0 to 29° south latitude).

• Biogeographic Regions
• oriental oriental
  • native native
• australian australian
  • native native
• oceanic islands oceanic islands
  • native native

Habitat

In Australia, black flying foxes are found in the subtropical and tropical latitudes, primarily in the coastal areas of the northern territory and as far as 250 km inland. Their habitat consists of rainforest, eucalyptus open forest, and savanna woodland. They roost primarily in bamboo, rainforests, and mangroves. However, there have been a few known roosting sites in caves and overhangs. Palmer and Woinarski (1999) found that, during the cooler dry season months, 74% of black flying foxes roosted in bamboo, 20% in mangroves, and 6% in rainforest habitats. During the build-up season (characterized by warming temperatures and early rains), 68% roosted in rainforest, 17% roosted in mangroves, and 15% roosted in bamboo. During the wet season, 52% roosted in rainforest, 28% in bamboo, and 20% roosted in mangroves.

Black flying foxes roosting in bamboo thickets roost 12 to 16 m off the ground, space themselves less than 1 m apart, and forage predominantly in woodland habitat. Those roosting in rainforests roost more than 18 m off the ground, space themselves approximately 1 m apart, and forage predominantly in forest and rainforest habitat dominated by Melaleuca species. Females use camps more than males, and smaller camps tend to be primarily made up of males and sub-adults.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest

• Wetlands
• swamp swamp

• Other Habitat Features
• riparian riparian

Physical Description

Pteropus alecto has a black body with some lighter hairs, and a black head. These animals may have a brown eye-ring, and often have a reddish collar on the back of the neck. The legs are furred to the knee, but are hairless below. The forearm length measures 153 to 191 mm and average weight is 667g.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Little information exists on mating systems in black flying foxes.

Peak birth times are correlated with periods of maximal plant productivity, hence, the timing of births varies with location. In Brisbane, Australia, most births are in October to November. In the northern territory of Australia, peak birth times are from January to March, and births in November are unusual but not rare.

It takes females 14.8 to 17 months and males 16.3 to 18 months to reach adult size. Females tend to grow faster than males. On average, females gain 2.56 g/day and their forearms grow 0.25 mm/day. On average, males gain 2.28 g/day and their forearms grow 0.15 mm/day.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous

Little information exists on parental care in black flying foxes. As mammals, it is likely that females play the largest role in parental care. They provide offspring with protection and nourishment until they are independent and weaned. However, beyond that basic speculation, information is not available.

• Parental Investment
• no parental involvement
• pre-fertilization
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting

Lifespan/Longevity

It is unknown how long black flying foxes live, however, it has been estimated that the females which survive to maturity would need to live about 7 years to maintain a stable population. Approximately 30 % of females born survive to maturity, compared to 37% in males. Survival rates vary between camps and between years. In years in which food is more abundant, lower levels of mortality are expected.

Behavior

Pteropus alecto is a nocturnal species. During the day, P. alecto roosts in colonies called camps. Typically males will travel between roosts more than females throughout the year. However, females travel further distances from roosting sites to food than males do. During the build-up season, females will travel between roosts more than at any other times of the year. Both males and females travel further between roosting sites and food during the dry season than any other season.

• Key Behaviors
• arboreal arboreal
• flies
• nocturnal nocturnal
• motile motile
• migratory migratory
• colonial colonial

Home Range

Palmer and Woinarski found that males travel an average of 6.8 km, and females travel an average of 5.8 km between roosts. On average, when foraging at night, males will travel 6.2 km and females will travel 10.9 km from their roosts.

Communication and Perception

Little information exists on communication in black flying foxes. However, as mammals, they are likely to use visual signals, tactile communication, scent information, and vocalizations.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Black flying foxes are dietary generalists known to feed on fruits, pollen, and nectar of 23 rainforest species. These species include Carpentaria acuminata , Terminalia microcarpa , Diospyros littorea , Elaeocarpus arnhemicus , Ficus opposita , Ficus racemosa , Ficus scobina , Ficus virens , Eucalyptus miniata , Eucalyptus papuana , Eucalyptus polycarpa , Eucalyptus tetrodonta , Lophostemon grandiflorus , Lophostemon lactifluus , Melaleuca dealbata , Melaleuca viridiflora , Syzygium nervosum , Passiflora foetida , Grevillea pteridifolia , Nauclea orientalis , Timonius timon , Cupaniopsis anacardioides , and Gmelina schlechteri .

Black flying foxes forage on different resources depending upon the time of year. During the dry season, they forage primarily in Eucalyptus open forest. During the build-up season, they forage primarily in the Melaleuca open forest, and during the wet season, they forage primarily in rainforest. It has been suggested that P. alecto selects sites that are richer in resources than floristically similar sites, which suggests that apparently similar habitats are actually different in resource abundance.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
  • nectarivore nectarivore

• Plant Foods
• fruit
• nectar
• pollen

Predation

Little information exists on predation in black flying foxes.

Ecosystem Roles

Because of its ability to access patchily distributed resources, P. alecto probably plays an important role in connecting isolated fragments of rainforest by transporting seeds and pollen between feeding sites. It is probably an important pollinator of 2 Eucalyptus species in northern Australia, and it is also probably an important pollinator and seed disperser in Syzygium species.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

Throughout much of its range, P. alecto is hunted for food.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

It is estimated that the Australian commercial fruit industry loses approximately $20 million per year to flying foxes (not just P. alecto ). Because of this, P. alecto is shot as an orchard pest in many areas. It also is known to carry/contract bat Lyssavirus , which is similar to the rabies virus and can be contracted by humans. However, it is not known how easily Lyssavirus is transmitted to humans or other mammals.

• Negative Impacts
• crop pest
• causes or carries domestic animal disease causes or carries domestic animal disease

Conservation Status

Pteropus alecto is currently listed under CITES appendix II and is not mentioned on the IUCN Red List or the U.S. Endangered Species Act.

Other Comments

There have been some individuals that appear to be hybrids between black flying foxes and grey-headed flying foxes ( Pteropus poliocephalus ). These individuals had characteristics of both parent species, however, genetic testing of these hybrids failed to confirm that they were hybrids. The authors note that further testing needs to be done to conclude whether or not these individuals are actually hybrids.

Additional Links

Encyclopedia of Life

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Diane Ten Pas (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

References

Palmer, C., O. Price, C. Bach. 2000. Foraging ecology of the black flying fox (Pteropus alecto) in the seasonal tropics of the Northern Territory, Australia. Wildlife Research , 27: 169-178.

Palmer, C., J. Woinarski. 1999. Seasonal roosts and foraging movements of the black flying fox (Pteropus alecto) in the Northern Territory: resource tracking in a landscape mosiac. Wildlife Research , 26: 823-838.

Thatcher, O. 1998. "Pteropus alecto" (On-line ). Accessed 12/03/02 at http://www.biology.leeds.ac.uk/staff/dawa/bats/Fruitbats/ALECTO.HTML .

Tidemann, C., S. Kelson, G. Jamieson. 1997. Flying-fox damage to orchard fruit in Australia - incidence, extent and economic impact. Australian Biologist , 10: 177-184.

Tidemann , C., M. Vardon, J. Nelson, R. Speare, L. Gleeson. 1997. Health and conservation implications of Australian bat Lyssavirus. Australian Zoologist , 30: 369-376.

Vardon, M., C. Tidemann. 1998. Reproduction, growth and maturity in the black flying-fox, Pteropus alecto (Megachiroptera: Pteropodidae). Australian Journal of Zoology , 46: 329-344.

Vardon, M., C. Tidemann. 2000. The black flying-fox (Pteropus alecto) in north Australia: juvenile mortality and longevity. Australian Journal of Zoology , 48: 91-97.

Webb, N., C. Tidemann. 1995. Hybridization between black (Pteropus alecto) and grey-headed (P. poliocephalus) flying-foxes (Megachiroptera: Pteropodidae). Australian Mammology , 18: 19-26.

CITES. 2000. "CITES Official Documents. Appendices I and II" (On-line ). Accessed 12/03/02 at http://www.cites.org/eng/append/I_II.shtml .

U.S. Fish and Wildlife Service. 1999. "Endangered and Threatened Wildlife and Plants" (On-line ). Accessed 12/03/2002 at http://endangered.fws.gov/wildlife.html#Species .

IUCN. 2002. "IUCN Red List of Threatened Species" (On-line ). Accessed 12/03/2002 at http://www.redlist.org/ .