(MY) Bats natural controller of pests

[Guest guest]

letters - the star 11 0ctober 2005

 

Bats just one natural way to control insect pests

 

THE spirit of the article, " Scientists: Bring in insect-eating

bats<http://thestar.com.my/news/story.asp?file=/2005/9/30/nation/12174225 & sec=na\

tion> " ,

(*The Star*, Sept 30) quoting me was to promote the use of natural predators

in controlling insect pests and not dengue per se. Why bats?

 

Most bats feed on insects and can consume vast quantities. Studies in

Britain have shown that a small bat may consume up to 2,000 small insects a

night or 1,000 mosquito-sized ones an hour.

 

Total reliance on chemicals to manage pests will, in the long term,

contribute to environmental degradation and foster resistance in the

targeted (and non-targeted) species.

 

Unfortunately, this suggestion seemed to have elicited a negative response

based on some misconceptions, " Bringing in bats will only compound

problem<http://thestar.com.my/news/story.asp?file=/2005/10/2/focus/12202566 & sec=\

focus> " ,

(*Sunday Star*, Oct 2).

 

I would like to clarify the two points raised in the letter.

 

1. Bats are not strictly night-flying animals. Most bats are more active at

dusk and dawn, particularly those species that favour small flies (including

mosquitoes).

 

Studies in the Pacific Islands (on plant-visiting bats) and Northern Europe

(on insect-eating bats) have shown that bats do feed in the day because of

inadequate energy intake at night.

 

Bats also have a variety of feeding modes, the common ones being capturing

insects in flight or picking them off vegetation/ ground.

 

Bats are also opportunistic feeders taking advantage of seasonal emergence

of insect swarms e.g. termites. Even day-flying insects sitting/sleeping on

vegetation/ground may be captured.

 

This is because the bats (with the exception of Old World plant-visiting

bats) have a highly sophisticated ultrasound (sonar) system that can

distinguish the insect from the background clutter.

 

2. It is true that bats carry viruses but so does most other wildlife.

Wildlife has been a reservoir for viruses for millenia but human-induced

changes to the environment has contributed to the emergence of new or new

variants of viruses.

 

Thus it is crucial to identify the reservoirs, mode of transmission and take

appropriate remedial measures.

 

However, human practices such as deforestation, eating wildlife and trading

of wildlife at wet markets have caused viruses to jump from animals to

animals, and animals to humans.

 

By abusing our environment and encroaching on wildlife, what we end up with

is a lethal viral time bomb waiting to explode – nature's way of paying

back.

 

The option here is either eliminate all wildlife or change our ways.

 

The Government is at a wit's end trying to figure out how to control the

mosquitoes that carry dengue given that there is no vaccine.

 

Even if the bats are shown not to consume the aedes mosquitoes, at least

they will help control other insect pests. For example, since the West Nile

virus outbreak in the US, some homeowners have built bat boxes to control

nuisance insects, including mosquitoes.

 

Our suggestion is just a small contribution towards these efforts.

 

Lastly, I would be the last person to make a lame suggestion as I spent a

week in hospital stricken with dengue about 10 years back, an experience I

do not fancy repeating.

 

*PROF DR A. ZUBAID,

 

Malaysian Bat Conservation & Research Unit,

 

Faculty of Science & Technology,Universiti Kebangsaan Malaysia.*