1)
Who are the Bats?
More than 1000 species of
bat are found all around the world. Bats are the second mostly occurred mammal
group. Bat are varying from species with body size lighter than a penny to ones
with wingspan with 6 feet.
Bats belong to order
Chiroptera under the class mammals. Bats are the only flying mammal found in
the world. Their forelimbs are modified as wings, and they have a
light-weighted skeleton for the flying mode of life.
Diet: Bats
show vast diversity in relation to food habits. Most of them are adapted for
insect-eating. Most of the remaining bats are fruit-eating or nectar feeders.
Some bat species prey upon other animals like frogs other than insects. Very
few species feed on other animals’ blood.
Habitats: They
are found in each, and every habitat in the terrestrial environment expect the
arctic region. But, the greatest species diversity of bats is recorded in
tropical regions. Many species of bats inhabit natural ecosystems like rainforests,
desserts, and mountain forests. However, a significant number of bat species
are adapted to live in urban and suburban areas, parks, crop fields, and
pasture farms.
Roosting place:
Only a few fruits eating bat species are found as diurnal (active during
daytime). Almost other bat species are nocturnal. They only go out for their
food and water at night. They spend their daytime sleeping. So, bats require a
safe place for resting to prevent predation attacks during the day. Such a
place is called as roosting place. Trees with dense canopy and caves provide an
ideal roosting place for bats.
Adaptation for night
flying mode of life: Bats are evolved to use echolocation to
find food sources and fly at night without crashing into objects like trees and
buildings. Bats create sound waves that coming back to them after a bounce off
from objects. These sound waves help bats to understand the size and distance
of the objects away from them. Each bat individual can create unique sounds and
recognized their sound after the reflection. As bat nocturnal bat use sound for
location, they have large ears for effective echolocation.
2)
What is the classification of bats?
1. Microbats:
The majority of bats are classified under microbats. Most of the microbats are
insect-eating (insectivore) bats. Few other species feed on the blood of other
animals such as cattle and they are named as vampires.
2. Megabats:
More than 150 bats species are found as megabats. Some of the megabat act as
nectar and pollen feeders, called pollinators, while others feed on
fruits, called as frugivores. The majority of megabats are larger than the
microbats in the body size.
3)
What are the functions of bats?
Pollinators: The
pollination of flowering plants are referred to as “chiropterophily”. Some
plants are partly or wholly dependent on the bats for the pollinators. As bats
are active during the night, they feed mainly on the nocturnal flower blooming
plants. Bats supports for the pollination of more than 500 flowering plants
around the world. Bat act as only pollinators for the plants in harsh
ecosystems like mountain ranges where the insect pollinators cannot be found.
Compare to other types of pollinators, and they can carry a large number of
pollen grains of flowering plants into a long distance. As a result, it
increases the possibility of cross-pollination among plants. Thereby,
bat support to increase diversity even within the same plant species. These
flowers have a white or pale color appearance, strong fragrance, and tubular
shape for the attraction of the bats. Banana, Durian, Guava, Moonflower, and
Mango are a few examples for the plants pollinated by bats. These plants offer
nectar and pollen as rewards for the bats.
Seed dispersers-
Like pollination, flowering plants also depend on bats for their seed
dispersal. Frugivores bat act as seed dispersers for many flowering plants. Due
to the high species diversity of bats, they are adapted to forage on different
layers of the forests. According to a research finding, bats disperse more
seeds than birds do. They carry the ripped fruits away from the trees to long
distances. During their journey, they ingest the muscular fruits coat and drop
the seeds to the ground floor. If these seeds fell down to the environment with
favorable conditions, they start to germinate and grow while absorbing water
and essential nutrients from the soil. Cashew, Jack, Mango, Guavas, and some
pig species are the examples for the plants depends on bats for the s. These
plants make bats accessible for their fruits by bearing fruits along the stem
or the branches.
Prevent flowering plants
from local extinction: Fruit-eating bats play an important role
in reforestation in degraded woodlands by carrying seeds from trees in remote
areas. It also helps to increase the tree cover in the fragmented forest areas
due to various reasons like the construction of highways. Their seed dispersal
action prevents the local extension of plant species that are confined to a
specific area by facilitating more opportunities to expand into other areas.
Pest control:
Insectivores play a major role in the insect pest population control. They feed
on nocturnal insect species. One single bat can catch more than 600 insects
within one hour. They have adaptation like a long, sticky, protrusible tongue
for pray upon the insects. Bats help to control the vectors of disease cause
agents of humans, including mosquitoes. Thereby, bats control the spread of
infectious diseases in the human population. In addition, bats are important
for controlling insect pests like moths, grasshoppers, and beetles attack to
economic crops involved in agriculture. Thereby, bats’ feeding habits reduce
the cost of pest control in farming.
Biological indicator:
Bat is used as important biological indicators in the monitoring program of
the environment. They are highly sensitive to climate change impacts and
changes in the environment due to anthropogenic activities, and they tend to
respond quickly even for the slight change in their environment.
4)
What are the harmful effects of bats?
Transmission of diseases:
Bat acts as vectors (an agent transmit infectious stage of pathogens to other
living beings) for some bacterial and virus origin diseases. As bat also
belongs to mammals, there is a high possibility for the bat to being infected
by rabbis. But there is a low risk for the transmission of rabbis from bats
into a human. The rabbis can be transmitted to humans by contacting salvia of
infected bats or through biting of infected ones. Furthermore, droppings of
some bats species cause a lung disorder named as histoplasmosis. It is a kind
of fungal disease, and the human becomes infected by direct contact through
inhaling the airborne fungus spores in droppings or indirect contact through
contaminated soil by the bats’ droppings.
Reservoir for infectious
diseases: Bats serve as the reservoir (an agent facilitate
pathogens to survival, growth and reproduction) for many diseases cause agents,
and most of them cause an outbreak of diseases in humans all around the world.
Viruses associated with bats have the ability to undergone adverse genetic
variation as they adapt to different environmental contexts.
5)
What are the threats for the bats?
Habitat fragmentation and
habitat degradation: Human activities, including the
construction of roads, power plants and buildings, the transmission of high
voltage power lines, and intensive agriculture, cause fragmentation of large
forests and make them unfavorable for native species. And also, the extraction
of timber removes large and fruit-bearing trees from the forest ecosystem. As a
result, bats face extinction due to loss of flower and seed-bearing trees, and
roosting habitats.
Climate change:
Climate change has shifted the blooming season of many flowering plants or even
blooming does not occur in all the year. It leads to starvation in the bat
species that are partly or wholly dependent on pollen and nectar of these plants.
And also, the changes in the blooming season alters the consecutive seed
production. It affects the frugivores bat that involves the seed dispersers for
these plants.
Predator attacks: Household
pets like cats pray upon on the small-sized bats. The increase in the household
cat population force a threat to some bat species.
Illegal trade for bush
meat:
Some African nations involved in illegal hunting and selling bats. In the
bushmeat trade, small-sized frugivore bats are mainly targeted. But, some countries
hunt insectivore bats as well. These bushmeat trade often carry out within the
nations, and sometimes it spreads beyond the boundaries. As bats have a
relatively low reproduction rate, uncontrolled hunting puts additional pressure
on the extinction of bat species.
Spread of diseases: The outbreak of infectious diseases may cause adverse effects on a bat population.
As an example, the bat population in the United States and Canada undergone a
sudden decrease in the population in 2012 due to the spread of white-nose
syndrome, which is caused by fungi called Pseudogymnoascus destructans.
These diseases usually affect the skin of ears and wings of bats living caves
with the humid condition.
Accidents:
Due to windmills, bats deaths occur in two ways. Some have died when they hit
the blades of wind turbines. Most of the bat deaths links with the damage to
internal organs like lungs resulting from air pressure reduction around the
windmills. When a high voltage power line is transmitted along the transit routes,
feeding sites, or roosting habitats, bats are more likely to sit on them. If
bats sit calmly on one high voltage line, it doesn’t make any
threat to their life. But, if they expand their winds and touch adjacent lines,
a complete circuit is built though their body as water and ions present in
their body act as a conductor. It generates current and causes shock in bats
and ultimately leads to death.
6)
How can farmers attract bats?
Farmers have to provide
forage, water, shelter, and roosting places to attract bat for pollination, and
pest control. So, they have to plant the nocturnal booming crop plants like
banana and cocoa in their farmlands. For bats evolved to roosts in trees,
species with dense canopy should be grown along the margin of the farmlands. Besides,
trees are abundant with numerous insect pest species. Thereby, it ensures the
continuous food supply for the insect-eating bats throughout the year. An
artificial shelter should be provided for the bat species that favor resting in
human-made structures. As bats lost nearly 50% of their body water daily, the
supply of fresh water in a small pond or tank will attract bats to farms. Excess
and harmful lighting should be avoided around the farmlands.
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