Beez Neez now Chy Whella

Megabats

Big Bear and Pepe Millard

Thu 5 Dec 2013 23:27

Fruit Bats, Flying Foxes or Megabats

The book says, “Clinging in their hundreds to casuarinas trees in the village of Ha’avakatolo are the native peka or flying foxes. It seemed most appropriate to find a tree in a graveyard to see these chattering creatures up close and personal. The lads painting the church opposite laughed and cheered as they watched me scale a wall and tiptoe back and forth as I marveled at these little batmen. Much smaller than the ones we had seen in Neiafu, but they will most certainly do for now.

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. Fox Island, Australia, is believed to be home to the largest colony of flying foxes on the continent. Our new little friends were happy to pose.

Description: The megabat, contrary to its name, is not always large: the smallest species is two and a half inches long and thus smaller than some microbats. The largest attain a wingspan of five and a half feet, weighing in at up to three and a half pounds. Most fruit bats have large eyes, allowing them to orient themselves visually in twilight, also 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: Megabats are frugivorous or nectarivorous, i.e., they eat fruits or lick nectar from flowers. Often the fruits are crushed and only the juices are 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.

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: Fruit bats have been found to act as reservoirs for a number of diseases which can prove fatal to humans and domestic animals, 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. 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.

Other viral 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.

Fruit bats are considered a delicacy by South Pacific Islanders as well as in Micronesia. Consumption has been suggested as a cause of Lytico-Bodig disease on the Micronesian island of Guam, through bioaccumulation of a plant toxin that the bats are immune to.

Classification: 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. In the 1980’s and 1990’s, 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. However, a recent flurry of genetic studies confirms the more longstanding notion that all bats are indeed members of the same clade, the Chiroptera. 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. To us a bat is a bat...........