Are Spiders Attracted to Light?

In this article we’ll answer the question, Are spiders attracted to light? But if you’re in a rush and just want to know the quick answer:

most species of spiders are attracted to light at night, especially if the lighting system is bright. Any device that emits light at night is highly likely to attract a spider. In fact some spider species prefer to hunt in bright daylight.

That being said, there’s way more to this than a simple answer paragraph. So keep reading we’ll discuss it in-depth and reveal some surprising facts about how spiders behave in light!

How Do We Know They Are or Aren’t Attracted to Light?

Well, this is a quite straightforward process to determine. Spider species that are attracted to light are usually active during the night. On the other hand, species that prefer to hunt when it’s bright are usually active during the day.

Are There Some Species of Spider that Prefer Light to Dark?

Absolutely! They are spiders that are active during the day and prefer to hunt when there is light. They are usually known as diurnal spiders. But this is only limited to certain species of spiders that have better vision. (Spiders with poor vision, tend to avoid too much light and hence they hunt in the evenings and at night).

It should be noted that these insects usually have a pair of even eyes. So, the more the number, the higher the likelihood of them hunting during the day. Generally, diurnal spiders usually want to benefit from the UV rays. These rays from the sun are known to affect the quality of the silk that’s produced.

So, those species that are active during the day usually require UV rays to enhance the strength of their silk in order to lower their risk of falling victims to predation as well as improve their defense mechanisms. Understand that these spiders usually have a silk-producing gel that highly depends on these rays for effectiveness.

Are There Some Species of Spiders That Prefer Dark to Light?

Yes. They are known as nocturnal spiders because they prefer to come out and night and go to sleep or rest during the day. This type of spiders usually take their webs down during the day and then rebuild new ones in the evening to catch new prey.

It should be noted that they usually consume silk from their previous webs in order to conserve their building resources. Nocturnal spiders usually start to come out between 6 pm and 9 pm.

Female nocturnal spiders are likely to build their nests around 8 pm and research studies indicate that this is the peak time for web construction. Well, we all know that when it’s “ladies’ night” everything tends to peak up early, right? Well, probably that’s the reason female spiders build their webs this early.

The main reason why nocturnal spiders come out at night is to hunt. It makes it easier for them since their prey is tired and fatigued after a day of moving to search for food. Additionally, they are safer and this time compared to during the day.

Let’s take a look at this; during the day, there is lots of light, heat, as well as movements all of which are destructive when it comes to hunting. Besides that, a lot of animals including their predators are usually active during the day.

So, the safety of these bugs is enhanced because even their predators such as birds are normally asleep at this time. Well, this is an intelligent way of them avoiding to become delicious snacks!

Note: Some spiders usually construct a web that they stay in both during the day and at night. However, we have nocturnal spiders such as the Garden orb-weavers that remove their webs every morning and construct a new one every evening. Quite tasking, right?

What Evolutionary Advantage Drove Them to Prefer One Over the Other?

Spiders that come out during the day are commonly known as diurnal spiders. During the evolutionary history of spiders, some of them changed to the diurnal lifestyle from the nocturnal. This was caused by an uncontrolled change in the environment that featured irradiation caused by sunlight.

When comparing the two, diurnal spiders are highly likely to get affected by the UV irradiation as they mostly move around during the day. However, there are fewer chances of nocturnal spiders being affected by the same UV irradiation.

But this irradiation effect comes with lots of advantages to the diurnal spiders. Like we know, spiders mostly trap insects by using their web. So, they must consistently build webs if they are to survive. However, a weak web means that only fewer insects will be trapped.

But research studies indicate that the presence of UV lights usually affects the orb-weaving bugs in a positive way. It improves the mechanical properties of the web by strengthening the draglines of the spider, leading to the making of stronger webs. As a result, these insects are able to trap their prey even better.

Note: this means that when it comes to maintenance, nocturnal spiders usually spend more tie rebuilding the orb web in order to trap more prey effectively.

From this, it’s clear that the lifestyle change embraced by the diurnal spiders has led to a positive life change. They now have the chance to create mechanically stronger silks required for the construction of their webs.

It’s important to also note that most of the spider species that function and hunt during the day usually have body colorations that are conspicuous. Well, does this have any association with the presence of UV light?

In summary:

Nocturnal spiders: they come out at night in order to avoid predators that are usually active during the day. They also take advantage of the tired and fatigued prey that are usually asleep at night.
Diurnal spiders: normally use the UV rays from the sun in order to produce silk that is strong for defense and trapping prey.

What’s the Mechanism behind Spiders Being “Attracted “to Light at Night?

Understand that spiders are not the only insects that are attracted to light. There are so many other insects that also prefer this mode of lifestyle. When flying insects are not typically attracted to light.

What usually happens is that the presence of light usually confuses them. As a matter of fact, it disorients their natural or original sense of direction.

According to some research studies, these insects that prefer to move out at night gave evolved from depending on natural light sources. Previous, nocturnal spiders used to depend on the stars and moon in order to navigate at night.

Well, these heavenly bodies are not too bright and probably this explains why the spiders with poor night vision depended on them. But since the moon and the stars are quite far, from the spider’s point of view, they don’t move. So, these insects will simply use them as travel guides because they are located at one point.

That’s why they used to “follow” them by simply maintaining a certain angle when they are flying in search of food or avoiding predators. They would simply use these points of reference till they could find food or finally decide to rest before continuing with the journey.

However, with the development of technology, lights, especially outdoor lights started to pop up everywhere. As a result, these insect’s hunting journeys got interfered with as the unnatural light sources would pop up in their usual field of vision.

With the presence of closer and brighter light, the angle of their movement changed and this means that they now switched towards a localized bright light.

So, the main reason why these insects move towards light bulbs, as well as electronic devices at night, is because they are disoriented as a result of visual confusion.

Well, that’s why nocturnal spiders are more likely to land on your phone or computer screen at night than any other point. Note that these are usually highly opportunistic insects.

That’s why they prefer to hunt in solitude in order to feast on as much prey as possible alone. They definitely take advantage of this visual disorientation to feast on the unsuspecting insects.

Are Spiders Attracted to Specific Colors of Light?

A study that was published by the University of Cincinnati indicates that certain spider species are attracted to specific color hues. For instance, wolf spiders are attracted to only ultraviolet and green colors. Well, this is because they have dichromatic vision.

Basically, it means that wolf spiders are colorblind but they are still sensitive to the green wavelength. Generally, these bugs are usually attracted to light with short wavelengths and that means that they are more likely to be drawn to UV light which can help them to see better and improve their navigation.

It’s for this reason that they are attracted to lighting sources, especially the sunlight. Even though nocturnal spiders tend to avoid light, you might find that some of these insects are attracted to bulb lights as well as phone and computer screens.

That’s why you are more likely to see these bugs at night, cycling near light sources such as bulbs. If you leave lighting sources when it’s dark, then this acts like a catalyst that attracts the insects to move to a specific location.

Spiders are attracted to bright lights, especially when the bulbs are surrounded by other flying insects that they can feast on.

If you want to learn more about various insects, then checkout our site categories, we have a bunch of articles there that are totally worth reading:

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All the best

Steve