The Asiatic Lesser Yellow Bat
By: David MacKay
Description and Rationale
The Asiatic Lesser Yellow Bat – A New Solution?
The Asiatic Lesser Yellow Bat is a native bat to the Philippines that lives in many urban areas, and nests in abandoned buildings and attics. They are regarded as pest in some places, and are not appreciated for the overwhelming help that they provide. These bats are carnivorous and prey on small insects like mosquitoes that can carry harmful diseases.
What is the Asiatic Lesser Yellow Bat’s impact on local ecology and insect populations? Is it a predator of other organisms besides small insects? If so, does this greatly alter the ecosystem that it lives in? How is its presence affecting the people’s livelihood? Does the bat cause damage to agricultural crops? Does the bat damage urban buildings? Is it a competitor for other insect eating organisms? Is there a reason that many people hate the bats and think that they are pests?
Are there ways that the bat can improve the livelihood of people? There is a major problem with insect born diseases that can spread rapidly in packed poorer areas, such as dengue fever and malaria. The bats are a natural predator of such insects (like the mosquito) that could be utilized to get rid of the problem. What are some ways that the bat could aid in this way? Could they be kept as pets to rid a home of the pests? Or could cheap ‘bat houses’ be built in squatter areas to eradicate the problem all together? Would using bats improve the quality of the environment? By using bats and not pesticides would it be more cost efficient? What are the best ways to communicate the findings to the people and barangays that have close packed quarters? Another use of the bat could be its guano. Is this a good fertilizer? Is it a cheaper alternative to other types of fertilizer?
The initial purpose of this project will be to research the biology and ecology of the Asiatic Lesser Yellow Bat. This will be done through a search of the literature as well as firsthand observations and interviews with people who have problems with insects. These initial findings will help guide the experimental phase, where key variables in the Asiatic Lesser Yellow Bat’s usefulness will be further explored.
It is hoped that new uses of the Asiatic Lesser Yellow Bat might help improve the health of people living in close living conditions where disease is spread quickly. This could be accomplished through a more informed understanding of a useful aid in the fight against insect born diseases.
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Biology
Common Names and Synonyms
The Asiatic Lesser Yellow Bat is also called Scotophilus kuhlii. It also goes by other names such as the Lesser Asiatic yellow house bat, or the Yellow House Bat (because of its tendency to live in urban areas and nest in houses). Other synonyms include: Netopýr (Czech), and Skotofilo Kulia (Esperanto), and in the Philippines it is referred to as ‘Bat’
Classification
Kingdom: Animalia --Animal
Phylum: Chordata --Chordates
Class: Mammalia --Mammals
Order: Chiroptera --Bats
Family: Vespertilionidae -- Evening bats
Genus: Scotophilus –Yellow bat
Species: Scotophilus kuhlii --Lesser Asiatic Yellow Bat
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Morphology and Physical Description
The bat can grow up to about 9 cm in length, and up to 22 grams in weight. The body is like a rodent’s (though on the contrary it is not one at all) with long velvety wings and a forearm length up to 5.2 cm.
The face is dog-like with a blunt muzzle and large, pointed ears. Although the eyes are small and poorly developed, they are not nearly blind. Vision is used as an aid in navigation especially at long distances, beyond the range of echolocation. Their senses of smell and hearing are excellent (as they use echolocation as they hunt for food at night). The tail is long and enclosed in the membrane between the hind legs. The light brown to yellowish fur is extremely soft to the touch.
There are some interesting things about the internal anatomy of Yellow House Bats as well. While other mammals have one-way valves only in their veins to prevent the blood from flowing backwards, bats also have the same mechanism in their arteries. Also the finger bones of bats are much more flexible than those of other mammals. This is because that the cartilage in their fingers lacks calcium and other minerals nearer the tips, increasing their ability to bend without splintering. The cross-section of the finger bone is also flattened instead of circular as is the bone in a human finger, making it even more flexible. Also the skin on their wing membranes is a lot more elastic and can stretch much more than is usually seen among mammals.
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Getting Food
The Yellow House Bat is carnivorous with its diet consisting mostly of small winged insects (like moths, flies, and mosquitoes). They rely on echolocation to locate their pray, as they are flying around at night. They are able to eat 1000 mosquitoes per minute (greatly reducing the risk of disease being spread via these pests)
Reproduction
Yellow House Bats reproduce sexually. Only the mother cares for the young, and there is no continuous partnership with male bats. Mother bats usually have only two offspring per year (twins), with the baby bat referred to as a pup. Their population, however, does not get out of control, as their mating season is only during rainy season. Pups are usually left in the roost when they are not nursing. However, a newborn bat can cling to the fur of the mother and be transported. Bats often form nursery roosts, with many females giving birth in the same area, such as a tree hole, or a cavity in a building. Mother bats are able to find their young in huge colonies of millions of other pups. At the age of two years, bats are sexually mature. A single bat can live over 20 years, but the bat population growth is limited by the slow birth rate
Environmental Factors
In its natural habitat, the Yellow House Bat roosts communally in hollow trees, but the species has adapted well to urban areas and frequently roosts in large numbers in attics or abandoned buildings. They also commonly roost in buildings and in "tents" formed from modified palm fronds. They forage in urban and agricultural areas and secondary forests from sea level to about 600 m.
There are several disease organisms that may use the Yellow House Bat as a host (as the bat is a mammal, it is susceptible to many diseases that other mammals are). These include the Issyk-kul (Keterah virus), and the Rabies virus. It is also susceptible to parasitic infections and bacterial infections.
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Origin and Distribution
The Yellow House Bat can be found from Pakistan and throughout India to Burma, Thailand, Indochina, Peninsular Malaysia, Singapore, Indonesia (Sumatra, Java, Bali, and Borneo) and the Philippines. It has not been introduced to any other countries (that have been noted).
Importance to People
As these bats are nocturnal hunters, they cut down on a major amount of insects that are pests to people and carry many dangerous diseases. In many places ‘bat houses’ are built to attract bats in the same way that bird houses attract birds. This is a cheap and relatively easy way to bring bats into an area where one wants them to eat many harmful insects.
They are of no worth as food and are not eaten, and they are also not sold much at all. Their major worth is held in their natural habitat is where they are able to cut down the amounts of harmful insects.
In some places there are local superstitions that these bats are vampires, or that they cause bad luck, but these are unfounded, as the bat feeds only on small insects. This can cause people to get rid of them and destroy their habitat. There are also uses for the bat’s guano, as it is good fertilizer.
Survivability and Endangered Status
As the bat is native to the Philippines, it does not interfere with other organisms’ ways of life. It is not in any sort of danger and is not at risk of loosing its habitat (as it can live in abandoned buildings). It also does not have any natural predators, and its only threat is that of people who kill the bats as if they were pests.
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Potential Solutions
Are the benefits of bats being utilized in the Philippines? The Asiatic Lesser Yellow Bat is the most common bat in the Metro Manila area, but it appears to be left alone and not utilized to improve the livelihood of people living in the Metro Manila area. There are many places around the world where people use bats to their benefit, but there seems to be no action taken to further the usefulness of the bat. There is no information found by this researcher that would imply that the bat is any harm to the environment, or the people living in the same area with these bats. There is common superstition all around the world that the bats are evil, and that may be why there have been no steps taken to further the usefulness of the bat.
There seem to be several promising livelihood possibilities that may benefit people living in the Metro Manila area. Below are 2 possibilities, with an analysis of the advantages and disadvantages for each. Along with each possibility, is a current status report of progress made to date, on each of the possibilities.
Possiblity 1: Bat Guano Fertilizer
It is found that bat feces (guano) are great fertilizer for plants. This completely natural material will benefit the plant and soil system without any other expensive ingredients. In addition, the guano can be used in any state of freshness (fresh, semi-fossilized or fossilized). Guano is provided in the ready to use condition. Guano can be used inside or outdoors for all living plants. Guano supplies fast and slow release nutrients to the biological system.
Advantages:
1. The Guano is much cheaper to use than regular manure if it is harvested naturally. Also, a smaller amount is needed to cultivate plants than ordinary barnyard or poultry manure. Using this cheap fertilizer could boost the income of farmers, and other food growers, by reducing the cost of fertilizer and the amount needed. This would result in a better crop output, and higher income.
2. The gathering of this bat guano could be a source of income for those who do not grow food. They could sell the guano as fertilizer to those who don’t have a way of getting any of this useful bat waste.
Disadvantages:
1. The guano could be hard to come by if there is no cave or dwelling place for the bats to live, thus being hard to collect the sporadic waste of the bats flying around. The time spent on trying to gather the guano may be too long and difficult.
2. If the guano is unable to be found, it may be too expensive for poorer farmers, and food cultivators to purchase. Further analysis would need to be taken to find out the average cost for this natural fertilizer.
3. The scent of this waste could be unpleasant to some, and could turn off those who would want to use it fresh, for indoor decorative plants.
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Possibility 2: Natural Pest Control
It is well known that there is a problem with mosquitoes and other insects that carry diseases such as dengue fever and malaria. These sicknesses can spread very rapidly in closely packed areas such as squatter areas. There is little that can stop the disease from spreading, without doing harm elsewhere in some form. Bats are able to help stop the flow of mosquitoes, yet it can be very sporadic where the bats choose to live.
In many places in the United States, where there is a high bug count, there are structures built to attract bats to live in them. These ‘bat houses’ are much like bird houses and can attract bats to live in many areas. The bats will hunt in close proximity to the houses.
This researcher conducted an interview with Pastor Nick Clarin, a respected community leader in Quatro. It was further discovered that the Barangay leaders would spray pesticides to kill the mosquitoes in the area, as a solution to the people’s complaints. Upon further discussion it was also found that the local residents were not afraid of the bats, and left them alone for the most part.
Although this researcher was unable to build a bat house for this project, he found that free plans to build them can be found on the Internet. After receiving plans for the bat house, this researcher’s family provided funds for the materials for Pastor Nick to build a bat house that would be mounted at the Quatro Ministry Center.
Advantages:
1. With the bat houses in place the bats could greatly lessen the population of mosquitoes. Thus possibly lessening the rates of dengue and Malaria.
2. These houses could improve the environment by limiting, or even eliminating the use of pesticides, to kill the pests. This could possibly benefit the people as well as the environment by getting rid of these poisons.
3. These Houses could greatly improve the livelihood of the bat’s themselves by providing them a habitat. Also it could get the bats out of people’s homes, providing better living conditions for both the bat and the residence of the house.
4. Christ’s love could be shown in the work put in to build these houses for the people, and a Christ-like example could be displayed in the way that we serve others who are in need of our help.
Disadvantages:
1. It is not known yet the price of materials for constructing these bat houses, but the houses could be considered an unneeded luxury to those whose budgets are tighter.
2. It could be difficult to build enough houses to supply enough help to all areas. It could take sponsors, or some sort of income to create enough bat houses to be provided for everyone in the Philippines.
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Possible Future Directions
A possible ministry could be set up to better the livelihood of the Filipino people by building bat houses and providing the means for construction around the Philippines. Kits could be provided to Barangay leaders for them to construct in highly populated areas, or in places where there is sitting water. It is hoped that through this ministry, the love of God could be spread to people, and show Christ-likeness through the work, time, and effort, put into this project.
It is hoped that further research could be taken to better the bat house system, to possibly provide a source of income for those who own them, by collecting the guano from the bats. Also, it is hoped that through further research, the mating cycles of the bats could be better learned and the bat populations could be protected. This would ensure greater numbers of bats to combat disease carrying pests.
Lastly it is hoped that, through the future of this project, a major step could be taken in the fight against dengue and malaria, and to better the lives of millions.
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Bibliography
“Answers to questions about guano fertilizer, bat or seabird.” BareRoots. 2002. May 4, 2008. <http://www.living-learning.com/faq/guanfaq.htm>
“Bat House Project: Economy Bat House Plans.” Bat House Research Project. 2008. May 4, 2008<http://www.batcon.org/bhra/economyhouse.html>
“Bats: Important Reservoir Hosts of Emerging Viruses.” CMR. 2008. May 4, 2008. <http://cmr.asm.org/cgi/content/full/19/3/531/T2>
“Bat” Wikipedia. 2008. May 4, 2008. <http://en.wikipedia.org/wiki/Bat>BioLib - Scotophilus kuhlii (Lesser Asiatic Yellow Bat.). 2008. May 4, 2008. S<http://www.biolib.cz/en/taxonnames/id34789/>
“ITIS Standard Report Page: Scotophilus kuhlii.” ITIS. 2008. May 4. 2008<http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=all&search_value=Scotophilus+kuhlii&search_kingdom=every&search_span=exactly_for&categories=All&source=html&search_credRating=All>
“Lesser Yellow House Bat.” Kruger National Park. 2008. May 4. 2008 <http://www.krugerpark.co.za/africa_lesser_yellow_house_bat.html>
Pastor Nick Clarin. Personal Interview. 2 May. 2008.
“Scotophilus kuhlii of Philippine Mamillian Fauna.” The Field Museum. 2002. 4 May. 2008. <http://www.fieldmuseum.org/Philippine_Mammals/Scotophilus_kuhlii.htm>
Seow K.M., Wong C.H. Gee Y.L., Zubaid A. Kamis A.B. Histological study on the male reproduction status of Scotophilus kuhlii in a fragmented forest
<http://pkukmweb.ukm.my/~rsenr3/rsenr1/P783-790.pdf>
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