Megabat

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Megabats
Temporal range: Oligocene–Recent
Large flying fox, Pteropus vampyrus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Chiroptera
Suborder: Megachiroptera or Yinpterochiroptera
Dobson, 1875
Family: Pteropodidae
Gray, 1821
Subfamilies

Nyctimeninae
Cynopterinae
Harpiyonycterinae
Macroglossinae
Pteropodinae
Rousettinae
Epomophorinae

Megabats constitute the suborder Megachiroptera, family Pteropodidae of the order Chiroptera (bats). They are also called fruit bats, old world fruit bats, or flying foxes.

Contents

Description[edit]

Spectacled flying fox (Pteropus conspicillatus)

The megabat, contrary to its name, is not always large: the smallest species is 6 cm (2.4 in) long and thus smaller than some microbats.[1] The largest attain a wingspan of 1.7 m (5.6 ft), weighing in at up to 1.6 kg (3.5 lb).[2] Most fruit bats have large eyes, allowing them to orient themselves visually in twilight and inside caves and forests.

Their sense of smell is excellent. In contrast to the microbats, the fruit bats do not use echolocation (with one exception, the Egyptian fruit bat Rousettus egyptiacus, which uses high-pitched clicks to navigate in caves).

Behaviour and ecology[edit]

Megabats are frugivorous or nectarivorous, i.e., they eat fruits or lick nectar from flowers. Often the fruits are crushed and only the juices consumed. The teeth are adapted to bite through hard fruit skins. Large fruit bats must land to eat fruit, while the smaller species are able to hover with flapping wings in front of a flower or fruit.[citation needed]

Frugivorous bats aid the distribution of plants (and therefore, forests) by carrying the fruits with them and spitting the seeds or eliminating them elsewhere. Nectarivores actually pollinate visited plants. They bear long tongues that are inserted deep into the flower; pollen passed to the bat is then transported to the next blossom visited, thereby pollinating it. This relationship between plants and bats is a form of mutualism known as chiropterophily. Examples of plants that benefit from this arrangement include the baobabs of the genus Adansonia and the sausage tree (Kigelia).

As disease reservoirs[edit]

Fruit bats have been found to act as reservoirs for a number of diseases which can prove fatal to humans and domestic animals,[3] but the bats themselves sometimes have no signs of infection.

Researchers tested fruit bats for the presence of the Ebola virus between 2001 and 2003. Three species of bats tested positive for Ebola, but had no symptoms of the virus.[3] This indicates the bats may be acting as a reservoir for the virus. Of the infected animals identified during these field collections, immunoglobulin G (IgG) specific for Ebola virus was detected in Hypsignathus monstrosus, Epomops franqueti, and Myonycteris torquata.

The epidemical Marburg virus was found in 2007 in specimens of the Egyptian fruit bat, confirming the suspicion this species may be a reservoir for this dangerous virus.[4]

Fruit bats are considered a delicacy by South Pacific Islanders as well as in Micronesia where, on the island of Guam, consumption has been suggested as a possible cause of Lytico-Bodig disease.[5]

Other diseases which can be carried by fruit bats include Australian bat lyssavirus and Henipavirus (notably Hendra virus and Nipah virus), both of which can prove fatal to humans. These bats have been shown to infect other species (specifically horses) with Hendra virus in Australian regions. Later, humans became infected with Hendra virus after being exposed to horse body fluids and excretions. [6]

Classification[edit]

Head of a masked flying fox or fruit bat (Pteropus personatus)
Livingstone's fruit bat Pteropus livingstonii
Fox Island, Australia, is believed to be home to the largest colony of flying foxes on the continent.

Bats are usually thought to belong to one of two monophyletic groups, a view that is reflected in their classification into two suborders (Megachiroptera and Microchiroptera). According to this hypothesis, all living megabats and microbats are descendants of a common ancestor species that was already capable of flight.

However, there have been other views, and a vigorous debate persists to this date. For example, in the 1980s and 1990s, some researchers proposed (based primarily on the similarity of the visual pathways) that the Megachiroptera were in fact more closely affiliated with the primates than the Microchiroptera, with the two groups of bats having therefore evolved flight via convergence (see Flying primates theory).[7] However, a recent flurry of genetic studies confirms the more longstanding notion that all bats are indeed members of the same clade, the Chiroptera.[8][9] Other studies have recently suggested that certain families of microbats (possibly the horseshoe bats, mouse-tailed bats and the false vampires) are evolutionarily closer to the fruit bats than to other microbats.[8][10]

List of species[edit]

The family Pteropodidae is divided into seven subfamilies with 186 total extant species, represented by 44 - 46 genera:

FAMILY PTEROPODIDAE

Footnotes[edit]

  1. ^ E.g., the Mauritian Tomb Bat. See Garbutt, Nick. "Mauritian Tomb Bat." Mammals of Madagascar: A Complete Guide. Yale University Press. 2007. p. 67. [1]
  2. ^ Nowak, R. M., editor (1999). Walker's Mammals of the World. Vol. 1. 6th edition. Pp. 264-271. ISBN 0-8018-5789-9
  3. ^ a b National Geographic, October 2007. "Deadly Contact," David Quammen, pp. 78-105.
  4. ^ "Deadly Marburg virus discovered in fruit bats". msnbc. August 21, 2007. Retrieved 2008-03-11. 
  5. ^ Monson, C. S.; Banack, S. A.; Cox, P. A. (2003). "Conservation implications of Chamorro consumption of flying foxes as a possible cause of amyotrophic lateral sclerosis-parkinsonism dementia complex in Guam". Conservation Biology 17 (3): 678–686. doi:10.1046/j.1523-1739.2003.02049.x. 
  6. ^ "Hendra Virus Disease & Nipah Virus Encephalitis Fact Sheet". CDC. 
  7. ^ Pettigrew JD, Jamieson BG, Robson SK, Hall LS, McAnally KI, Cooper HM (1989). "Phylogenetic relations between microbats, megabats and primates (Mammalia: Chiroptera and Primates)". Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences 325 (1229): 489–559. Bibcode:1989RSPTB.325..489P. doi:10.1098/rstb.1989.0102. 
  8. ^ a b Eick, GN; Jacobs, DS; Matthee, CA (September 2005). "A nuclear DNA phylogenetic perspective on the evolution of echolocation and historical biogeography of extant bats (chiroptera)" (Free full text). Molecular Biology and Evolution 22 (9): 1869–86. doi:10.1093/molbev/msi180. PMID 15930153. Archived from the original on 2009-02-13. 
  9. ^ Simmons, NB; Seymour, KL; Habersetzer, J; Gunnell, GF (2008-02-14). "Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation". Nature 451 (7180): 818–21. Bibcode:2008Natur.451..818S. doi:10.1038/nature06549. PMID 18270539. "recent studies unambiguously support bat monophyly" 
  10. ^ Adkins RM, Honeycutt RL (1991). "Molecular phylogeny of the superorder Archonta" (PDF). Proceedings of the National Academy of Sciences of the U.S.A. 88 (22): 10317–10321. Bibcode:1991PNAS...8810317A. doi:10.1073/pnas.88.22.10317. PMC 52919. PMID 1658802. 

References[edit]

External links[edit]