Lots of people want to deter bugs from lingering around their porch light and many lights are advertised as not attracting insects. But what if you want lots of insects? What kind of light could you use on a porch that would attract the most insects?
So what you’re going to want is a cheap white sheet that you don’t care about, some way to hang it (I use big binder clips on my back fence), and something like these
and an outdoor outlet. Turn them on in the summer around sunset and you will attract swarms of moths and other nocturnal insects like you’ve never seen. Welcome to light trapping!
Note that these black lights also come in USB form
This makes the whole system very transportable (and thus independent of an outdoor outlet) when combined with a portable USB charger.
Light traps are a good way to attract moths and other nocturnal insects for species documentation. Because your intentions are unclear from your post, I do want to add a note that light traps should be used somewhat sparingly. Sustained outdoor lighting (every/most nights) is not a sustainable way to attract insects to your yard. If you are looking to increase your yard’s insect diversity, reducing light pollution and planting native plants are the better route.
A relevant thread:
Ethics of Attracting Moths to Light
This isn’t exactly true, and in fact (and surprisingly) not true in many cases.
Abita Entomological Study Site in LA has run 200+ light traps for 40 years, 365 days/year. Their capture records, particularly those concerning populations, indicates that their light traps (despite the strength and quantity) have had no impact on the moth populations.
Regardless of the effects on moth and/or other insect populations (which are likely nuanced), light pollution has deleterious effects on the environment.
Ecological studies can and should weigh the costs-benefits of methods using sustained light traps. But in general, I believe hobbyists should be discouraged from sustained light traps, especially if you aren’t even checking the light traps all night, every night anyway.
My 175W Mercury Vapor uses, well, 175W. And while Lumens aren’t directly equal to wattage, I’ll bet just about everyone here has more than 175W of lights on most nights. A single street light puts out more light.
Meanwhile, the crash in some families of moths has been linked to pest and agricultural insecticides. That’s the real problem for moths, and undoubtedly many other invertebrates.
I don’t suggest anyone refrain from attracting moths or insects at night; it might lead to valuable information and knowledge.
I’m not suggesting that light traps are a major player in total light pollution. My personal carbon footprint is insignificant compared to that of many industries, but that doesn’t prevent me from mitigating my own footprint when reasonable. Likewise, I try to mitigate my contributions to light pollution (not just regarding sustained light traps, but also by reducing outdoor lighting around my house and the use of heavy curtains at night).
Again, moths and invertebrates are not the only organisms affected by light pollution. Also, this line of reasoning is along the same lines as “outdoor cats don’t pose a viable risk to bird populations because habitat loss is a more serious threat.” The existence of larger contributing problems doesn’t negate the possibility of smaller problems.
And just because outdoor lighting has a negligible effect on some or most invertebrates, doesn’t mean it can’t have a disproportionate effect on more narrow groups (e.g., fireflies). Also, I’d like to note that the Xercies Society, leaders in invertebrate conservation, specifically list light pollution (in general) as a threat to moths, fireflies, and other insects.
I myself have used and enjoyed light traps to document moths and other nocturnal insects. My caution was specifically regarding sustained lights. If the OP had been asking about the best light trap setups, I wouldn’t have commented. But because their question was specifically about porch lighting, I wanted to caution against leaving a porch light on all night every night, especially if…
I’ll add my 2 cents for a simple setup. I use a folding camping chair, a few heavy things, and a white sheet in the driveway. Setup is: deploy the chair, drape sheet over back of chair, weigh down corners of sheet (bricks work well and, if it’s windy, I’ll use a golf club to keep it taught), plug in UV lamp (mine is from entoquip), hang lamp over back of chair, and sit back and watch. I run the lamp for 2-3 hours a night then unplug it and let the insects disperse. Only counting nocturnal visitors on the moth sheet, I’ve seen over 210 species this year, including several iNat first records (globally and regionally).
Merely adding UVA/UVB blacklight under my security light has increased the number of insects I’ve been able to observe. I don’t even bother with the white sheet.
Not all UV lights are equal though. I tried an LED UV light last year and saw very little difference. I suspect it was because the bulb was intended for parties and posters. I now use a UVA/UVB bulb that is designed for reptile keepers to keep their charges healthy. It works much better.
I agree. Since security lights are needed where I live, I replace one bulb of the front & back lights with a blacklight. I have a dark house. I’ve tried a white sheet. I see no difference between the backgrounds. However, the blacklight attracts SO MANY beetles, I often just leave standard halogen bulbs in.
There’s no shortage of insects here, new species every week for 3 years.
I do turn off the back lights facing a field during firefly season.
I believe the person who posted the question has the privilege of living in the same bug-laden region.
One additional comment to my post below. I’ve never heard this advised before, it’s just my own observation. I think going out nightly for three years (during insect season) has enabled me to see more species than using powerful lights and huge sheets several times a year.
I see some moths, for example, only for a few nights, then never again all season. Ditto with beetles. Their appearance is exquisitely timed with their host plants. They find their mate, do their thing, lay their eggs and bye-bye until next year.
Going to different elevations or niche ecological regions would be great, but that’s not my circumstances at this time.
I’ve found the same thing. I’ve been concentrating heavily on moths the past couple of years and I’ve noticed that some moths only show up for a few days but others show up for weeks. A single moth trap event conducted every few weeks can’t capture the same detail.
@kevintoo that’s common with many taxa, and surprisingly in tropical jungles even. You’ll also find that male and female flight periods may overlap only a few days. Not sure where you are without looking at your profile first, but I can tell you that in NE USA the Saturnid populations are crashing- now might be your last chance to get observations of some species. Callosamia promethea used to be so common at the light to be an annoyance; last year I didn’t see a single one.
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