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What is attracted by a UV lamp ?

After several years of nights spent to watch moths using my UV-lamps, I noticed that light do not only attract moths. Indeed, many other things are attracted. Some are surprising, some are funny, some can even be scary... I wanted this paper to be funny with no scientific matter.

The stuff I am using is described here. I am usually mothing alone and I can say that I observe many more things (moths excluded) when alone than when accompanied. I am presenting the things as a list of species organized by biological groups.

Insects and other invertebrates.

Of course, not only moths, but also a huge quantity and diversity of insects are attracted by light. The complete list would certainly be very long. Some species, like golden ground beetles and glow-worms, are very pleasant, some, like ichneumonids and hornets, are a lot less...

  • Caddisflies (Trichoptera) come to light in great number. They look like moths and beginners can easily mistake them. Contrary to moths, they have chewing or atrophied mouthparts (as criquets ; most of the moths have a proboscis, i.e. siphoning mouthparts) and they have no scale on their wings.
  • Many flies (diptera) : midges, mosquitoes, fruitflies, crane flies, etc... They come sometimes in very impressive number, by thousands or even tens of thousands, mostly in June-July. Then, you cannot avoid swallowing accidently a few of them then you come close to the lamp. The good point is that mosquitoes mostly bites at dusk and very little in the middle of the night.
  • Spiders. You will mostly see species hunting by running on the ground. They are not aggressive and not unpleasant, but they can steal one or two moths. opiliones come as well quite often to the light and very often to the sugar to feed on it. You can often watch matings. Millipedes and centipedes regularly visit sugar too.
  • Water boatmen, like Sigara spp.. Usually, no more than a few dozens come to the light, but once, an astronomic number of them came to the light in a dry valley. There were even millions of them. I could take a full handful of them... Armless, but quite unpleasant because they are everywhere around the lamp... You should know that many aquatic insects are able to fly then adults and that they move from pond to pond by the air.
  • Backswimmers. As the previous species, except that you should avoid to catch them in your hands. They are never present in great number.
  • Diving beetles and Water scavenger beetles. They live underwater and are able to fly. They never come in great number, but the arrival of a Great Silver Water Beetle is very impressive. This is the largest beetle of Belgium. It is armless but the spines on its legs are quite unpleasant. As any other large beetle, it makes the mess around the lamp...
  • Ground beetles, both flying and not flying species. It is always very pleasant to see a golden ground beetle coming to the light. The small red-legged ground beetles (genus Pseudophonus ?) are a lot less pleasant. They fly, the are often numerous (although they seem to be not present in my present moths sites) and they go everywhere. When I say 'everywhere', it means 'everywhere': on you, in your hairs, in your clothes... and even in your underclothes... as I say, everywhere... it is itchy, but they are armless, fortunately...
  • Longhorn beetless and Stag beetles, at least some species, come easily to the light. Small species are not annoying, but large species can be very restless and make the mess among the frail moths. It is better to catch them and keep them in a small box until the end of the observations.
  • Cockchafers frequently come to the light, where they are present. The use of light is a good way to find them.
  • Glowworms, Lampyris noctiluca. In fact, only the males fly and come to the light. They are small, very quiet and you might not notice them. You might also see a female standing in the surroundings but they do not seem to come to the light. At once, I catch one to observe it on my hand. Less than 30 seconds later, a male landed on my hand and jumped on her to have sex...
  • Among other beetles, burying beetles come frequently to the light. These beetles bury small dead mammals and birds to feed their larva. They are almost always infested by phoretic mites.
  • Earwigs are almost everytime found on sugar, sometimes in great numbers. They come sometimes to the light too.
  • Occasionnally, you might attract butterflies, such as Whites, Fritillaries or Blues that fell asleep on the grasses close to the light. It mostly happens in meadows with species that sleep on the grasses. I attracted Damselflies in the middle of the night as well.
  • Many parasitoid wasps. They lay their eggs inside or on the body of other insects, particularly caterpillars. Tha larva develop then inside the body of their host and devour them alive from the inside. They are armless to humans but the bite of some species (particularly the genus XXXXXXXX) is very unpleasant. It is probably the only insect that bit me with no obvious reason. However, in 99% of the cases, they just turn around the lamp and do not attack.
  • Much more unpleasant, hornets are also attracted by light, particularly i a nest is located close to the light. They are not aggressive but you should take care to avoid any accident. I can only advice to choose another mothing site if they come.
  • Cricket and grasshoppers are rarely attracted by light. Sometimes a Tetrix comes to the light. Nevertheless, criquets (such as Leptophyes punctatissima, Pholidoptera griseoaptera, Meconema spp.) come very often to sugar. It is very funny to watch 4 or 5 Meconema having lunch together on the same supar spot and running on the tree trunks.
  • Very surprising, I sometimes read that crayfishes come to the light. I did not saw that yet, but you should know that many crayfish species can move on dry land and so, can be attracted to light.

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Figure 1 : Caddisfly.

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Figure 2 : Opiliones mating, close to sugar.

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Figure 3 : Great Silver Water Beetle (Hydrophilus piceus) came to the light.

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Figure 4 : A female glowworm.

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Figure 5 : A burying beetle (Nicrophorus humator) with phoretic mites.

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Figure 6 : An ichneumonid.

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Figure 7 : Trio of crickets on sugar: Leptophyes punctatissima (left) et Meconema meridionale (center and right).

Vertebrates

They are probably the funniest and the less expected encounters...

Amphibians

It is quite surprising to see amphibians, i.e. frogs, toads and newts, coming to the lamp. The species that have a terrestrial life phase may patrol around by chance and be attracted by the light. Of course, this is not the case of full aquatic species. I see some from time to time almost all along the year, except in Winter.

  • Newts in terrestrial phase.
  • Common frogs can even climb the pyramid to come closer to the light.
  • Tree frogs. I remember one specimen who was absolutely determined to come to the light, even when we moved it a few dozen meters away.
  • Common toads. I do not remember a toad came to the light, but you may see some ferreting about for preys in the paths.

Birds

It is very surprising that even birds are attracted. In fact, they are not attracted by the light, but rather by the insects flying arount it. They are mostly birds of prey.

  • Eurasian Hobby Falco subbuteo is hunting flying insects at dusk. If insects are numerous around the lamp, it might be interested in catching some of them. I remember a hobby that was hovering in front of me. It was looking for an angle of attack to catch some insects around my light. It moved several times to try to find another angle. This little game lasted for several minutes.
  • Owls. In the same manner as falcons, they can be tempted to catch the insects flying around the lamp. You should take care if you have long hairs as they might mistake them with the tail of a squirrel or a small rodent. I never had any problem with owls, but I remember that a big owl (probably a Tawny Owl Strix aluco that nearly swooped down on my back. It renounced at the last second when it realized that the rodent was a lot bigger than expected. Also, when I was in Poitou-Charentes, I was quite scared by a Barn Owl (Tyto alba). I was mothing with a friend. He just had a flashlight in his hands. We installed ourselves in a clearing on the side of a limestone quarry. At around half past midnight, then everything was quiet, a barn owl came out from nowhere and swooped down on the flashlight. It tooked it in its claws and then it realized that it was in front of a human. It then let go of the flashlight and disappeared as it came. The guy even did not bat an eye ! Yet a barn owl is at least impressive with its white color and its wingspan of nearly one meter !
  • Although they do not come to light, I can often listen to birds sing at night or at dusk. They are especially European Nightjars (Caprimulgus europaeus), owls and Common Nightingales (Luscinia megarhynchos). Eurasian Reed Warblers (Acrocephalus scirpaceus) usually sing after 2 am.

Mammals

Mammals are probably the most spectacular observations at night. Almost all species can be spotted. The best advantage of my equipment is that it is fully silent and it does less frighten the animals. They often are dazzled by the lamp and even do not become aware of my presence.

  • Hedgehogs are not shy at nightand I can often see them ferreting around. They can come to arange of a few meters but I never saw any coming to the light. They are obviously not interested in catching the insects came to the light. Twice, I could watch the nuptial display and the mating. They were surely too busy to worry about my presence.
  • Deers are among the most beautiful observations I made. You can listen to them barking in the springtime and summer, or just walking accross the woods. The blue light often puzzle them as they are not used to see it at night. They usually do not expect to meet a human and can come sometimes very close to the light. Totally blinded by the light, they do not remark my presence. Once, a male even came at a range of 4 meters with no fear. He continued his way quietly as if I was not there.
  • Rodents and shrews do not come to the light, but I can see one sometimes coming close to the light. However, they remain very shy. They include muskrats and common rats.
  • The garden dormouses can be spotted in favorable sites but they are also very shy. They do not come to light, but move in the trees. A few times, I could see garden dormouses coming to my sugar mixture. Obviously they love alcohol !
  • Wild boars can pass nearby. I never saw anyone, but at least once, I could listen to the grunts of a herd that was skirting me.
  • Mustelids are usually very shy. However some individuals are more foolhardy and can come closer. Indeed, they are not attracted by the light and they meet us just by chance. I remember a marten that crossed the path at a range of 10 meters. It came back in the other way 45 minutes later exactly at the same place. Each time, it stopped to watch me a few seconds. Another time, a polecat or a marten was moving along a forest path towards me. Blinded by the lights, it could not see me. Unfortunately, a mosquito cam into my mouth at that moment and I coughed... and it disappeared in the bushes before I could take a picture.
  • I never saw a badger during my moth nights but I would not be surprised if it happens one day. Nevertheless, when I was mothing with my bike, I was lucky enough to meet one on the side of a secondary road.
  • Many times, I was lucky to watch foxes at night. Most of the time, it happens at dusk. They are usually young individuals that are not yet frightened by humans. Sometimes, they are gamboling at a range of a few dozens meters and do not worry about me. Other times, they sit down and watch me. But most of the time, they are just surprised to come accross me. I remember a young fox that did not spot me because of the height of the grasses and passed at a range of 2 or 3 meters of the lamp !
  • Bats are observed at almost all moth nights, but in Winter when they are hibernating. They are not shy and some even do not hesitate to pass at a few dozens centimeters from my head... and even to steal some moths around the light...
  • I think the most amazing meeting I made was a rabbit. I was mothing in a fallow with very high vegetation (about 1.5 m). In the middle of the night, I listen to a small animal coming straight towards me. At the moment, I was afraid it was a dog because there were some houses very close. But it came close enough to touch my feet, lift up again and realized it was just in front of a human. Then it ran away at full speed ! I am not sure who was the most surprised between me and the rabbit !

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Figure 8 : Alpine newt.

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Figure 9 : A common frog, good climber !

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Figure 10 : A Tawny Owl. Source : Rodrigo Saldanha de Almeida from Marco de Canaveses, Portugal

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Figure 11 : A pair of hedgehogs... very busy !

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Figure 12 : A deer... at 4 meters.

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Figure 13 : A garden dormouse... alcoholic ?

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Figure 14 : A fox.

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Figure 15 : Rabbits.

Humans

The funniest animals, but also maybe the most threatening too, are not wild... they are humans. Indeed, a light that is visible from far away in the night and is located in a place where nobody is expected to be at night, often attract people for diverse reasons: curiosity, local authorities, land owners, or just by chance. I always try to remain the most discrete as I can and always all the needed authorizations.

  • For more than 3 years, I am regurlarly mothing in a natural reserve surrounded by fishing ponds. One night, last year, as I was unloading my equipment from my car, two fish wardens called me to remind me that fishing is unallowed at night. When I told them I came for the moths, they did not know anymore what to say. The same night, I had a surprise visit of another fish warden. He was tracking me down for several months and thought I was fishing illegally ! I did not see him anymore after that.
  • At once, I was mothing on the bank of the Lys river. I was sitting on the tow path on the side of a wet meadow. A young man came in on a motor scooter. He was looking for his friends who were fishing illegally at night on the river. He first thougt it was an extraterrestrial attack when he saw my pyramid and my blue light. Then he saw me, he removed his crash helmet, ready to hurt me with it if I was trying and picking a quarrel with him... in fact, we talk a long moment about moths...
  • One night, at the edge of a forest, at around 2 am, I was removind my equipment then I was surprised to see a few people coming towards me with handlights. "POLICE !!!! SHOW YOUR HANDS !!!!" About ten policemen came to pick me up in the wood... Quite not reassuring when it happens... After I explained them what I was doing, we talked a bit about moths and they leaved. Another time, two gamekeepers came in to throw me out the wood. One was particularly angry and had a (broken) rifle with him... As I had all the authorization, nothing bad happened, but yes, it was very unpleasant...
  • At any time, when you are in a private property, you can be visited by the owner. It happened to me on hillsides. So it is very important to find informations and the agreement of the possible owners of a given site.
  • During a public moth animation, I was also visited by a group of scouts. That was very funny because they were playing a game using lights. A group had to find spots with foods and drinks in the dark and to avoid the lights of another group to not be catched. The main problem was one spot full of food was just behind us... and I was so hungry !!!
  • Curious people may always come to ask what you are doing, particularly in well-frequented places. It is often a good opportunity to meet people and to talk about moths.

Conclusion

My mothing nights are sometimes eventful... and it shows that everything is possible at night. I observed not only moths, but also many other things, sometimes very surprizing. I am just waiting for the coming out of an extraterrestrial !