The Night Workforce Sri Lanka Never Put on Payroll–The wrinkle-lipped free-tailed bat

Picture this.

Just after sunset, somewhere in Sri Lanka, a shift change begins at the entrance of a rock cleft, a cave or a crevice most people walk past without noticing. The air smells faintly of damp stone and guano, and the first flutter of wings sounds like someone riffling through thousands of paper envelopes at once.

The rock does not move. The earth does not tremble. Yet something unmistakable happens. The evening air fills with movement as bats stream out with the urgency of workers clocking in. They are not heading to a desk. They are heading to the night sky.

This is the wrinkle-lipped free-tailed bat, a species often listed as Chaerephon plicatus, and in some newer taxonomic treatments as Mops plicatus.

It has one of the worst public-relations records in the animal kingdom.

It also shows up for work.

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Why This Matters

Sri Lanka depends on jobs that never appear in job listings.

Wetlands hold floodwater without invoices. Mangroves reduce wave energy without overtime. Soil organisms keep farms productive without a pension plan.

Now add a flying insect-control workforce that clocks in at dusk and flies all night.

Across parts of South and Southeast Asia, peer-reviewed studies have shown that wrinkle-lipped free-tailed bats can feed heavily on major rice pests, including brown planthoppers, and that large colonies can consume very large numbers of insects in a single night. The exact figures depend on the location, the season, the colony size and what is available in the air that week. Still, the direction of the evidence is clear. When these bats are present in large numbers, they can be a meaningful part of natural pest suppression in rice landscapes.

Sri Lanka has this species too, but we are still early in understanding how many colonies exist, where they roost and what their nightly workload looks like here.

That is a key point. We do not need to exaggerate to be impressed.

If humans had a habit of paying attention only after something becomes expensive, this is where we would clear our throats and pretend we have always cared about bats.

The Challenge

Bats have spent centuries being assigned reputations they never applied for. Folklore, films and costume parties have done the branding work. Bats have just been trying to eat and sleep in peace.

Wrinkle-lipped free-tailed bats face an additional complication. The folded lip structure that gives them their name is part of what helps them operate in fast aerial hunting. Unfortunately, it also gives them an expression suggesting they have just attended a meeting where someone reheated tea twice.

Despite appearances, this is a serious aerial insect hunter. Studies describe this species as foraging at height and using open airspace where many other bats do not spend much time. That makes them useful in agricultural landscapes, and also harder for humans to notice and study.

Their workplace vulnerability is simple. It is housing.

Sri Lanka’s best documented modern record of a roosting colony comes from Sigiriya, where a colony of around 300 bats was observed in a vertical cleft in 2016, in peer-reviewed Sri Lankan bat research published in the Journal of Threatened Taxa. The same study notes the species had been recorded previously in Sri Lanka in 1935 and 1997, but a roosting colony had not been documented in between those points.

That tells you something practical. This bat may not be absent. It may be under-recorded.

Which means the easiest way to break the workforce is to seal or disturb the places it is using, before we even realise a shift is operating there.

Here is the human friction part, and it is rarely malicious. Someone fixes a crack in a wall with foam. A temple repaints and closes a gap to keep out “pests”. A contractor seals a crevice because it looks like unfinished work. The job is done neatly, efficiently and with good intentions. The night shift loses its door.

We are very good at tidying up nature’s loose ends. We just forget some of them were

entrances.

Chemical-heavy pest control can also complicate the job. Not because bats are fragile creatures who faint at the smell of a spray bottle, but because their whole business model depends on a steady, safe supply of insects.

Who’s Doing Something About It

If Sri Lanka is going to understand this night workforce properly, it starts with people who go where most of us do not, and listen to what most of us cannot hear.

At Sigiriya, a team that included bat biologist Dr Tharaka Kusuminda and zoologist Prof. Wipula B Yapa did the unglamorous, essential work of turning “there are bats here” into usable national knowledge. That meant field capture-based measurements, careful identification and recording echolocation calls so future teams can recognise the species by sound, not just by luck. That 2016 colony record is not just a fun fact. It is a baseline, the kind that quietly changes what a country is able to protect.

Elsewhere in Sri Lanka’s bat work, researchers and survey teams have been pushing for wider acoustic surveys, because many bats are easier to detect with listening devices than with eyes. Names that appear in Sri Lankan reporting and research coverage, including Chamara Amarasinghe and Dr Amani Mannakkara, sit inside that same practical reality. If you do not measure the night, the night stays invisible. Invisible workers are easy to erase.

And then there are the systems that determine whether knowledge becomes protection, or simply becomes an interesting paragraph that gets applauded and forgotten, like a good speech at a committee meeting.

The Department of Wildlife Conservation is the body that can act when habitats and roost sites fall within protected areas and regulated frameworks. The Biodiversity Secretariat at the Ministry of Environment is part of the machinery that turns species knowledge into national commitments, planning and reporting.

The Systems That This Work Runs Through

Species recording and verification

Without published records, a species can exist and still be operationally invisible. Peer-reviewed documentation like the Sigiriya colony paper is how “someone saw bats” becomes usable knowledge.

Acoustic survey capacity

Bats are difficult to observe directly. Expanding Sri Lanka’s acoustic survey coverage is one of the most practical ways to find roosts, map distribution and detect changes over time. It is wildlife research for animals who refuse to pose for photographs and do not fill out forms.

Protected area governance

Protected areas can safeguard roosting and feeding habitat when bats operate inside them, but many roosts can also occur outside protected zones. Without the governance layer, habitat loss becomes easier to approve by default.

Environmental review in development

Where environmental review is applied well, it can identify roosts and feeding areas before changes are made to rock faces, caves, buildings or vegetation corridors that bats rely on.

Agricultural practice and advisory channels

Integrated pest management and more careful pesticide use can reduce pressure on the insect base that sustains natural pest-control species. Without this, you end up paying twice. Once for chemicals, and again for the ecological services you removed.

The Job They Perform

In the simplest terms, this bat is part of a night workforce that eats flying insects.

In rice landscapes studied in other parts of Asia, wrinkle-lipped free-tailed bats have been shown to feed heavily on brown planthoppers and other insect groups that farmers spend real money trying to control. Researchers describe this as a form of biological pest suppression.

It does not mean bats solve pest problems alone. Agriculture is never that tidy.

It means bats are some of the unpaid staff members on the night shift, and in the places where they operate at colony scale, their contribution can be large enough to measure.

Sri Lanka’s open question is not whether bats eat insects. They do.

The open question is where this particular workforce is operating here, how big the shifts are and what happens to local pest pressure when those shifts are disrupted.

If you have ever wondered what it looks like when a country quietly loses a useful service, it usually starts with something that looked like a harmless repair.

What You Can Do

You could do this. And if not, that is completely fine too.

Easy

Talk about bats like they are workers, not villains. Public fear is one of the fastest ways roost sites get destroyed.

If you visit rock sites, caves or old structures, avoid disturbing roosting areas at dusk and early morning, when animals are leaving or returning. That is the shift-change bottleneck.

If someone shares bat misinformation in a group chat, correct one point calmly and move on. You do not need to win the internet. You just need to stop bad decisions becoming normal.

Practical

If you manage a home garden, reduce unnecessary pesticide use. Less chemical pressure helps keep insect communities stable, which supports the food base bats depend on.

If bats roost in a building, do not seal entry points suddenly. Consult wildlife authorities or experienced practitioners first. Many conflicts can be solved with timing and simple exclusion methods that avoid trapping animals inside.

If you are a farmer, agribusiness operator or part of an advisory network, support integrated pest management approaches that treat natural pest suppression as an asset, not an accident.

Deep

Support Sri Lanka bat research and monitoring. The country still needs broader acoustic surveys and clearer mapping of roost locations.

If you work in planning, architecture, engineering, tourism operations or heritage site management, ask a basic question early in projects: “Are bats using this structure?” Early checks prevent expensive fixes later.

If you are an educator, bring bats into environmental education as an ecosystem service story. Kids understand “night workers” immediately. Adults usually follow. Some adults will still ask if bats are vampires. You can treat that as a teachable moment.

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What We Still Need To Know

Nature and Science

This matters because “present” is not the same as “secure”, and Sri Lanka’s baseline data is still thin.

Where are the active roosting colonies in Sri Lanka today, beyond the sites already recorded?

How large are these colonies seasonally, and do they shift roosts across the year?

What does a healthy, stable colony look like in Sri Lanka’s different climate and land-use zones?

People and Culture

This matters because roost survival often depends on local tolerance long before policy arrives.

How do communities living near caves, rock sites and old buildings interpret bats, and what triggers eviction decisions?

Where are coexistence practices already working quietly, and what makes them work?

What concerns do people have that conservation messaging often fails to address?

Systems and Policy

This matters because good intentions collapse when workflows do not exist.

How often are bat roosts actually checked during renovations and development near rock faces, caves and heritage structures?

Where do environmental review processes routinely miss night-active wildlife, and why?

Which agencies have responsibility in practice when roosts are in public buildings, temples or private property?

Innovation and Technology

This matters because bats are measurable, if we choose to measure them.

Could a coordinated national acoustic monitoring network map bat activity over time without disturbing roosts?

Can Sri Lanka build shared protocols so different teams collect comparable data and reduce duplication?

What could citizen science contribute safely, without encouraging disturbance?

Moral and Emotional Lens

This matters because we all benefit from work we did not hire.

How do we respond when we realise we rely on a workforce we never acknowledged?

What does it say about us if we notice the job only after the worker is gone?

Final Thought

Every functioning system has workers whose names you never learn. You notice them only when the shift goes unfilled.

If Sri Lanka’s wrinkle-lipped free-tailed bats are part of the night workforce, then the first step is simple.

Stop firing employees you have not even met, especially the ones working the longest shift in the country.

Sometimes, protecting something begins with simply letting it keep showing up for work.

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