Oh the Entomology! Light pollution "radically altered" environment – making more bugs, more bug predators

From the University of Exeter , some buggy science. Next thing you know, PETA will be campaigning to have us shut off street lighting to “save the insects”. I’m surprised it has taken them this long to figure out that bugs like street lights. Perhaps like moths drawn to a flame, these scientists were drawn to a grant to study this. The results are another “could may, might” effect on the entire food chain. Something MUST be done. /sarc

Long exposures of insects under a street light. – Click for video

Light pollution transforming insect communities

Street lighting is transforming communities of insects and other invertebrates, according to research by the University of Exeter. Published today (23 May 2012) in the journal Biology Letters, the study shows for the first time that the balance of different species living together is being radically altered as a result of light pollution in our towns and cities.

Believed to be increasing by six per cent a year globally, artificial lighting is already known to affect individual organisms, but this is the first time that its impact on whole communities has been investigated.

This study shows that groups of invertebrates living near to artificial lights include more predators and scavengers. This could be impacting on the survival rates of different species, having a knock-on effect on birds and mammals that rely on these species for food. The effects could be affecting entire ecosystems and even humans.

The research team based their study in the market town of Helston in West Cornwall. They placed pitfall traps directly under and between street lamps that were 35 metres apart for a number of days and nights. This allowed them to compare, not only results for day and night, but also differences between areas under and away from street lights.

They collected 1,194 individuals covering 60 species. They discovered that total numbers were more abundant under street lights, where they also found more predatory and scavenging species, such as ground beetles and harvestmen. This was the case during the day, as well as at night, suggesting that the effect on communities is ongoing.

Lead author Dr Tom Davies of the Environment and Sustainability Institute at the University of Exeter’s Cornwall Campus said: “Our study shows that light pollution could be having a dramatic effect on wildlife in our towns and cities. We need to be aware of how the increase in artificial lighting is impacting on the delicate ecosystems on which we all rely. Our research shows, for the first time, the changes that light pollution is making to entire communities of invertebrates. We now need to examine what impact this is having on other communities and how this may be affecting important ecosystem services and whether we should change the way we light urban spaces.”


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In the UK we have had street lighting since Victorian times. Over that time no insect has suffered and those that predate insects are still with us. No change there then.


Do these researchers ever take a drive out to the country?


“We now need to examine what impact this is having on other
communities and how this may be affecting important ecosystem
services and whether we should change the way we light urban spaces.”
Which, translated to normal English is, “We need more funding.”
“Believed to be increasing by six per cent a year globally”…
Great. Now the bugs have models. From hockey stick
to fly swatter…


Shouldn’t that be PETI (People for the Ethical Treatment of Insects)?


I find this interesting, but it is so vague. What would be concerning is if they could show that street lighting has had negative effects on animals that hunt insects in the dark, including perhaps bats. Worth further study… maybe they could get some more grant money by claiming it has something to do with global warming.

Craig Goodrich

Yet another demonstration that the need for academics to publish produces an increase in invertibrate editors.


Written as if the man from Exeter actually IS a part of the food chain? As if we RELY on the invertebrates in our towns and cities? Rely? I’m thinking his hunting and gathering likely includes merely Tesco’s …..? 😀

“…Our study shows that light pollution could be having a dramatic effect on wildlife in our towns and cities. We need to be aware of how the increase in artificial lighting is impacting on the delicate ecosystems on which we all rely…”
Maybe they can get a grant to do the same study in North Korea.
Anybody who’s seen the satellite shots of North Korea at nighttime knows what I’m talking about.


“We now need to examine the impact on ….”
Translation: this should get me a few more easy pubs, maybe a Nature article if I make it scary enufff and link to “Climate Change”, and allow me to renew my grant so I can produce even more Biology PhD’s w/o jobs.

“Could” this…. “could” that… “may” the other… Truly fed up with grants being given out for utter nonsense as this. I’m voting UKIP at the next election, they are the only party with sensible policies on energy.

Somebody paid for this? Haven’t these folks sat out on their porch at night with the light on? If there ever was a study of something drop-dead obvious, this is it.

Crispin in Waterloo

I recall lying awake in bed in Kampala in the 80’s and hearing what sounded like a group of passing students on their way home from a party. Giggling and chatting, they were audible about the shrill of the night. But instead of carrying on down the road to Seven Mile Hill the party continued, hour after hour. What on earth was going on, I wondered.
In the morning my host Tom Gossen told me that the reason they didn’t move on was that nightly under each streetlight a group staked out a claim to the insects available and captured them throughout the night. I saw the critters for sale, roasted, at the market in the morning – 10 Ugandan ‘Shillingis’ each.
They were catching what appeared to be a type ‘katydid’. I am sure there are lots of edible bugs. Katydids are predators. This rather contradicts the study above: If the lights draw more predators, and the top predators is Man, then the lights are helping to reduce the number of predators, not prey – at least in some countries.
Hmm…. predators being eaten by top predators…. sounds suspiciously similar to the universe where Emperor Bokassa lived (dubbed the Central African Empire at that time) – he of ‘give a huge diamond to a French President’ fame. My lawyer friend in Bangui said his primary and immediate task when contacted by powerful clients was to spring them from the Central Prison before a certain top predator put out their lights and they found themselves, like those Kampala critters, deep-fried in oil. No kidding. My friend’s cook knew the top predator’s cook and you do not want to know the details.
The darkness of ignorance is on rare occasion preferable to the Light of Knowledge.

Jonathan Smith

Lucky for all these ‘delicate ecosystems’, that have endured everything nature has thrown at them, that these academics have arrived just in time to save them. If cockroaches can survive a nuclear war, aren’t a few streetlights a bit of a joke?

Berényi Péter

Eh, and God said, let there be light pollution: and there was light pollution. And God saw the light pollution, that it was good: and God diuided the light pollution from the abominable purity of darkenesse.


Obviously we need to study the sun as well, since its presence dramatically affects the movements of insects. We need to make sure the sun always shines exactly the same hours every day of the year in every place. No more seasons, no more clouds. Protect bugs against all unpredictable exigencies!

Tom in mosquito infested Florida

Next the animal police will want us to stop using insect repellant because it may deprive those lovable mosquitoes from an important food source.

M Courtney

If this is true then, so what?
Are we meant to abolish evolution?
How would living in darkness achieve that anyway?
Having said that, there are plenty of good reasons to think about whether lights need to be left on all the time. I’m just not sure that unpredictable microfauna changes is one of the best.

Harry Won A Bagel

Perhaps he overstates the results of his research a bit. However I do have a solution. Use more bug spray, particularly near lights. Personally I have a bug zapper, not because they are more efficient, they aren’t. A well directed cloud of poison is also more dramatic. It is that every time I hear that zap-sizzle noise I enjoy a frission , the thrill of victory, technology over nature. It is just so damn satisfying.

1) Ecosystems are not as delicate as they think. Of course, it does not serve their goals to admit so.
2) How about the ecosystems deal with us for a change? We are as natural as they are, only doing natural things.
3) Ecosystems are not static, they are always changing. Let them change. Who are they to say that some endangered species is not preserved by the advent of street lights? The reputed species extinctions caused by tiny changes in global temperatures are all theoretical. They postulate how many species that go extinct before we ever detect them—it’s fantasy “science.”
4) There is no aspect of our activities that does not have effects locally. Are we supposed to avoid ALL effects? It’s simply impossible. Stepping outside in the morning has an impact. All houses occupy land that cannot be used by a chipmunk to burrow a home or trees that can harbor birds. The hand-wringers would have us all disappear to save the environment from us. How about saving us from the idiot environmentalists?
5) It is the species that endear themselves to us that are the winners. At the moment, our entire planet is at risk, with all of its eggs in one basket. We need to colonize other planets or moons to reduce the chance of being wiped out by a single asteroid collision. Those animals that endear themselves to us, such that we take them with us, are the real winners here. The other species remain at peril and probably are due for extinction eventually anyhow. They have not stepped up and made themselves useful. That’s poor planning on their part.

So then, is North Korea practically bug free?

Come to think of it, winter is the most unproductive aspect of our world. We HAVE to do something about it. Think of the stress it puts on ecosystems of all kinds. Why have we let this go on for so long? Think of all of the death and destruction that it causes. If they think we can control the weather and climate, then we should be able to alter the seasons. Let’s get to it!

Darkinbad The Brightdayler

The effect is likely to be local and no different to an African waterhole except in scale.
Yes, light navigating insects, confusing the lamp with the moon will fly around in circles until exhuasted, they fall to the ground.
Yes, predatory and scavenging insects will exploit the opportunity and clean up.
Yes, there will be local abundance above the average density for the area.
I’m sure that they’ve found an effect. I’d be surprised if they didn’t.
I’ll bet they discovered a Lagrange point between the streetlamps!
What worries me is their progression from what they’ve observed to what they’ve inferred.
There needs to be a much more robust support in their discussion of the move from the particular to the general.


Here is an emperical observation for you all. I have LED, Curly CFL’s of different color temps, and plain old tungsten filament light bulbs in outdoor lights.
The LED consistently has the fewest flying critters around it, while the CFL’s have clouds of insects. The old tungsten also receives a great deal of attention.
I’ve installed LED’s with different color temps (wavelengths) and some receive slightly more attention than others, but overall attract flying insects far less than any other lighting.

F. Ross

Anthony, small one …in title “evironment” >>>environment?
REPLY: Fixed thanks, A

Jim Clarke

“We need to be aware of how the increase in artificial lighting is impacting on the delicate ecosystems on which we all rely.”
I don’t know about you, but I tend to rely an awful lot on artificial lighting, and not so much on the ecosystem of insects in and around the neighborhood. And what is it with this ‘delicate’ classification? Insects appear to be some of the most robust and adaptable life forms on a planet filled with robust and adaptable life forms. We can not get rid their ‘delicate ecosystem’ even when we try!
Academics and environmentalists have fallen in love with a biosphere that only existed for a brief time before the industrial revolution. This arbitrary selection of a ‘correct’ biosphere is not only scientifically ridiculous, but environmentally damaging.
These are the same people who use the theory of evolution as a litmus test for scientific literacy. You remember evolution: survival of the fittest, adaptability and all that jazz? But now, evolution is apparently a bad thing. Change is not supposed to happen and the survival of the weakest has become the noble cause of the modern environment movement.
Change is the life-blood of evolution and the enemy of modern environmentalists. Change is the only constant in the biosphere. Change is natural. Preventing change is unnatural. What does that tell you about the environmental movement?

Leo Morgan

It’s even worse than we thought!
Electric lights used to attract and kill moths the way candles do. Now the irrational have mandated CFL’s, and horny moths seeking mates no longer burn to death. 10 per household per year* times 115 million households* times .1 gram* per moth = 115 tonnes per year of extra moths mating and breeding ten thousand more each.
* Numbers Source:
1) I made it up
2) US census, rounded
3) Googled Website
4)Different Googled website.

Crispin in Waterloo

Is it the absence of a UV content in their spectrum that is so disinteresting? Lots of insects can see ultraviolet light. The LED’s are just three monochromatic colours, all visible to us, right?

Paul Grainger

Anthony, I’m sure that your remark about shutting off street lighting to “save the insects” was “tongue in cheek”.
However, in my home town of Tewkesbury, (UK), the authorities already DO turn off street lights early in some areas to protect the local insect life.


GE and the congress will see opportunity here to invent and allow only an ecosystem delicate balancing bug friendly low emission light bulb that no one wants or can afford.
For the first time in the history of man, except in N Korea and Mt Everest man has non-combustible light on demand in homes and the street for convenience, safety and security, he has drained the wetlands in Europe AKA swamps and that has been proven to be good for the health and progress of mankind.
Malaria’s decline in the United States and Europe in the late 1800s was due mainly to draining swamps and removing mill ponds. Anyone reading tombstones in early European and American graveyards can see the damage of swamps on humans, especially children 5 or younger. Removing disease and bug infested swamps has been called a bad thing by those who love such things. And now the light could be harmful to bugs and entire ecosystems.
We have seen dramatic effect on wildlife in towns and cities with the anti-hunting protection of the fox in the UK and bears in the US. Never mind these creatures in towns and cities could be harmful to humans.
Does anyone ever wonder why flying insects don’t head for the sun the biggest light of all?


What about save the worms? What about buildings and roads and the effects they are having on worms? Worms are the most significant and successful land animal on earth. They comprise some 90% of the total mass of land animals. Everything else pales in comparison.
Humans have gone from using 4% of the land surface 150 years ago, to using 40% today. Of that a significant fraction is pavement and concrete. What effect is this having on the soil below? Preventing water, air and sunlight from reaching the soil and thus having a significant effect on the ecosystem of the most important land animal on earth.
Tarmac roads need to be replaced with sustainable dirt roads in keeping with UN policy on sustainable development. Pavement and concrete levels must be immediately rolled back to 1990 levels, with a further 20% reduction by 2020 and a 50% reduction by 2050. This policy needs to be backed up by force if necessary using the full might of the UN. Selective bombing will be used as necessary to ensure all development is sustainable.
Reportedly the government of Oz is well aware of the problem. With help from NASA and the EU they are planning to implement the worlds first Tarmac Exchange. Large portions of Ozzie Tarmac will be torn up (no one will much notice the difference) and shipped to the Maldives and other island nations as part of “Operation King Canute”, paid for by a Tarmac Tax.
Every citizen in Oz will receive a Tarmac Rebate to offset the costs, to ensure that Tarmac Polluters pay their fair share. Those companies that are emitting the highest levels of Tarmac will pay the highest tax and thus save the most important land animal in existence.

And IPCC said: Let there be darkness!

Chuck L

All the insect community needs is (rimshot), a community organizer!!!

The swallows have returned to the old Spanish mission at San Juan Capistrano every March 19th for centuries. This happened to be my birthday, so a few years back i visited to savor the moment. Television news crews set up at the mission, ready for “live coverage” of the return. By the evening news there were NO SWALLOWS at the mission. Turned out that the then new, Mission Viejo Mall had converted the birds. The mall’s parking lot lighting allowed the swallows to catch bumper crops of flying insects in the cool of the night, along with new easy nesting sites. There is no longer is “special interest” news coverage of the “Swallows Return to the Mall”.

TDBraun says:
May 23, 2012 at 5:16 am
I find this interesting, but it is so vague. What would be concerning is if they could show that street lighting has had negative effects on animals that hunt insects in the dark, including perhaps bats.

The bats love it. The area around street lights becomes the bats’ happy hunting ground.

ferd berple says:
May 23, 2012 at 7:38 am
What about save the worms?

ferd, stop giving them ideas. To us it sounds crazy. Unfortunately, you might flip a switch in the wrong mind.


If bugs can accommodate street lighting, they can easily accommodate a bit of global warming (or global cooling, or climate change, or climate disruption, or weather weirding, or…)


At May 23, 2012 at 5:02 am you ask;

Do these researchers ever take a drive out to the country?

Yes, these went to Helston which is a small town ~10 miles up the road from me here in Cornwall. Apart from the nearby Culdrose naval airbase, Helston is very rural.
They could have done the study in Exeter where they are based.
They must have had a nice holiday, but I would have done the job at Helston with much lower travel costs. Or, if they had chosen Exeter, then TonyB could have done it for them during his frequent visits to study ancient climate records in the library at Exeter Cathedral.
Of course, in reality their doing the research at Helston shows they are at the bottom of the AGW-funding food chain. Helston is a nice holiday spot but not as good as Rio, Copenhagen, etc.

Tom in mosquito infested Florida says:
Next the animal police will want us to stop using insect repellant because it may deprive those lovable mosquitoes from an important food source.

What, you’ve never heard of Silent Spring? {/sarc}

Berényi Péter

The entire question could be solved by compulsory replacement of light bulbs by dark bulbs. A dark bulb would not emit harmful radiation, for it does not emit any radiation whatsoever. Is not it ingenious? It does not even consume electricity, so no connection to the network is needed either (great savings!). However, in exchange for these benefits one has to present the bills of dark bulbs purchased to the tax authority at the end of the fiscal year, and if the money spent on those marvelous earth-savers is less than the prescribed quota, the missing sum plus an appropriate fine should be transferred to the state’s account. These measures would surely put an end to any light pollution.
However, as some R+D is still needed to develop advanced dark bulbs, twice the amount of money collected this way is to be spent on grants, incentives and bank guarantees going to cutting edge enterprises.
/sarc off

Alan Watt

I know it is stereotyping, but whenever I see anything from an organization or department with “Sustainability” in the title, I assume the output is worthless.
In this case the problem aligns perfectly with the desired result: just enforce use of renewable power for streetlights and the lights will be dark most of the time. Bugs will be happy. People will be bumping into things, like streetlight poles and muggers.
Not really a problem because in the US hardly anybody walks anywhere more than a block away. This will just cause people to get in their cars and drive 1 block or less instead of walking so they can see where they are going and not run into muggers.
So on a more thorough examination, turning off the streetlights doesn’t make sense as the increased CO2 emissions from more automobile use will outweigh the decrease due to renewable energy use.
I shouldn’t have to, but “/sarc” in case anyone was in doubt.

Bruce Cobb

The concept of light pollution has been around for a while, and it is a real concern. One thing to point out is that it is light which is doing more than what is actually needed, meaning it is wasteful, in addition to whatever damage it may be causing the ecosystem. We humans are not exempt from the harmful effects either. Fortunately, there are relatively easy, and not very costly ways of dealing with it.

“could be having a dramatic effect on wildlife in our towns and cities”
Yeah, the herd of elk at the corner of Sunset and Vine.

Steve C

I find light pollution pretty objectionable, but it’s for astronomical rather than entomological reasons. Bet there are more astronomical objects you can’t see because of it than species of insect you won’t see.

John G

3% of earth’s land surface is covered with urban areas leaving 97% for the insects to do their thing free from streetlights. That of course ignores the problem of how to keep ’em down on the farm after they’ve seen Paris.


“This is the first time that its impact on whole communities has been investigated.” And for good reason, too. Previous generations knew it was a total waste of money to investigate the obvious and trivial.

Greg R.

DMatteson says:
May 23, 2012 at 5:08 am
Shouldn’t that be PETI (People for the Ethical Treatment of Insects)?
But that would be descriminatory. What of the arachnids? It should remain PETA (Peeps for the Ethical Treatment of Arthropods).


While I don’t have any comment on the study, I remember moving to a town where you could see the Milky Way at night from my back yard, 10 years and several shopping centers later… gone.


Lights at night attract bugs, and the bugs and small mammals that prey on them. The people who did this study , and the people who payed for it, and the people who published it, should all be ashamed of themselves for the wasted time, money and ink! This is the kind of stuff done in the 4th through 7th grade science classes.
Now, I do a lot of night fishing near bridges. And I’ve found that bait fish frequent the bridges where there are lights shining on the water. And I’ve found that is the place to fish at night for the predators that prey on those bait fish. In a nutshell, that’s my research and conclusion. All given to you fishermen out there for free.
Jay Davis


wow! More insects under street lights. Isn’t science wonderful.
(Are bugs are not attracted to lights lit by renewable energy?)


Not sure this would apply to the study, but:
The street light in front of my house was out for about 3 days, before I went out one morning to find my car window smashed and radar detector gone.
(the punks got the detector, but the wiring snapped where it enters the unit. Idiots.
Me for leaving the unit in plain sight, them for stealing a now useless item).