Moths are fascinating and one of the most diverse species on the planet, constantly catching the intrigue of entomologists, wildlife researchers, and avid bug collectors alike. One of their most talked-about aspects in the scientific community is their relation to rain and water. How do they fair during rainfall or in aquatic conditions?
Most species of moths cannot survive underwater and will also avoid getting impacted by rainfall. Heavy rain will decrease their agility and reduce their chances of survival. Aquatic moths, however, are a diverse group of moths that live underwater for a large portion of their lifecycle.
In this article, we are going to put these moths under a microscope and examine their relationship with water. We will see how these insects react to rain and why they do so. So, let’s dive into the captivating world of moths.
Can Moths Fly in Rain?
Moths are insects with very fine and light wings. They have only a few stabilizing parts and give a vulnerable impression. Nevertheless, moths are able to fly even when it rains. This is made possible by the special surface on the wings, which destroys and repels the water droplets in a very short time.
If you think about the proportions of a drop of water and a moth’s wing, you will come to the conclusion that a drop should be fatal to a moth if it were hit. A drop of water is relatively large and fast when it falls from the sky. Therefore, it has a lot of energy when it acts on the wings.
This is basically true and such an impact on a moth necessarily distributes its energy to the moth and influences its ability to fly. It reduces their maneuverability and makes it harder to move around. Such a moth in the rain will be an easier target for predators.
However, a drop of water does not impact a moth’s wing sufficient to injure it.
This is due to the impressive surface of the wings. These have small, fine hairs (scales) that act like fine needles when the water droplet hits them.
They prick the surface of the drop, causing the drop to break up quickly into many small parts. These tiny drops can only transmit little energy and are quickly repelled from the surface.
In this video, you can see how the big drop gets shattered and repelled within microseconds.
Of course, it is hard to recognize the effect of the tiny scales, but if you compare the impact with other surfaces you will be impressed.
This short video also shows, that faster drops (right) are easier broken up, than slower ones (middle). The impact of faster drops is huge, but the ability to distribute the energy is even bigger.
This incredible feature is one of the main reasons why moths can fly in the rain.
The scales of the moth not only destroy the water droplets but also prevent moisture from settling on the wings. If water were to accumulate on them, their weight would increase rapidly and ruin their ability to fly.
The anatomy of a moth’s wing is the most important prerequisite to survive in rain.
While moths can repel waterdrops quite effectively, it is still an impact that decreases their chances of survival.
And this impact can’t be avoided. A moth’s agility is quite low and the drops are comparable fast. There is no chance of outmaneuvering every single drop.
And that’s why moths will most often avoid rainy conditions.
Where Do Moths Go When It Rains?
Since moths are not the biggest fans of a stormy afternoon, they will look for shelter when the downpour starts. Typically, they will take cover under leaves or branches or hide in cracks until the rain passes. They fold their wings together and wait until the rain is gone.
More on that:
Where Do Moths Go During the Day?
Why Do Moths Stay in One Place?
Now, scientists are researching the exact relation between changing weather patterns and the behaviors of many insects, including some species of moths. The information they have now is not conclusive. But the research does hint at a potential correlation between the two, which may indicate that moths can sense changes in the weather.
Can Moths Swim?
The vast majority of moth species are incapable of swimming through all of their stages of development. But they will not drown instantly when they hit any body of water. They do possess some attributes that help to repel water to an extent such as the hairs on their wings and body. So, they can float around and move in the water.
This is helpful as they can climb up to dry land should they find themselves facing a watery grave.
Moths can’t start in the water and need to reach dry land to fly.
However, the aforementioned aquatic moths have evolved differently than their terrestrial counterparts. These species of moths can live either their entire life or a significant part of their life cycle underwater.
After the eggs hatch, the larvae cover themselves with a cocoon and then stick to a solid structure like a rock or log. After reaching full maturity, the adult moth will swim out of the water with the help of its wings and legs. They then head out for dry land and to find a suitable mate. Afterward, they dive back into the water to lay eggs and complete the cycle.
Are Moths Waterproof?
Moths are not waterproof but they have certain traits that help them to repel water and moisture. And in some species, namely the aquatic moths, they have a way of trapping air bubbles to help them survive underwater.
The tiny hair on their body prevents the water molecules to stick to their skin. Thus, giving the illusion that the moth is waterproof. But if you were to submerge most species of moths in any liquid for a long period, they will eventually succumb and die.
Aquatic moths have a unique advantage in this instance. They can form plastrons with the help of their body hair. Plastrons are basically air bubbles that help to diffuse oxygen without the water getting inside. So, the moths are able to breathe without drowning.
This is different from how fishes breathe through their gills, as they allow the water to get inside their body, and then the oxygen is transferred.
Can a Moth Survive If It Gets Wet?
Contrary to what some may believe, a moth is not completely hopeless once it gets wet. Yes, they would much rather prefer to remain dry. And a dried-up moth is much more agile and able to avoid predators better. But it is not the end of the word for them if they happen to get a few drops of water on them.
As long as their wings are intact, moths will still be able to fly about. So, the main issue that the insects try to avoid is getting their wings damaged by hail or strong winds during a storm. In the insect world, a flightless moth is essentially a dead moth. Animals that eat bugs as part of their diet can easily catch these moths and eat them.
As mentioned before a moth can easily repel small amounts of water. This will secure survival during most precipitations and short watery contacts.
This will become more difficult if the influence of the water increases. A moth put underwater or swimming for a prolonged time will lose its ability to fly. Water molecules will stick to the body and make the insect very vulnerable. It has to dry its wings first before it can continue to fly.
Do Moths Drink Water?
Moths do intake water to survive (like most animals) but not in the traditional method we are used to. Moths do not directly drink water from rivers or a puddle. They also do not need a huge amount of water as an adult.
But they do need some amount of liquid to maintain their normal bodily functions. And they get this water from absorbing things such as nectar or juices from fruits. Some even resort to animal droppings for their source of water.
And usually, this little amount of liquid is enough for them. Adult moths do not waste much time searching for food. A lot of them may even spend their entire adult life without consuming anything. Hence, they mostly depend on the food they intake when they were a caterpillar I.e., their larval stage.
Those species that do need food, will only drink it rather than eating it with their mouth. In fact, most moths do not have proper mouthparts for mastication and so, they are unable to bite at all. So, their diet is composed of entirely liquid or semi-liquid materials that can be digested directly, without the need for chewing.
Moths even don’t drink the way we expect. They can’t suck water into their mouth (and certainly not thick nectar). They use capillary action by holding their mouthparts onto the fluid and waiting until the molecules climb into their mouth.
As a larva, moths have a staggering appetite. They will consume pretty much anything, from actual food materials to synthetic substances such as wool, silk, and linen. So, even as a caterpillar, moths do not seek out active sources of water. Rather they depend on other food materials to fulfill their liquid requirements.
Can Moths Survive Without Water?
This depends on the state of their body’s water balance. Many varieties of moths only live for a few weeks as an adult. So, if they have plenty of liquid in the reserve for that duration, they can survive without drinking anything.
As we already mentioned, they will get their water from nectars or animal feces. So, they do not need a direct, clean source of water.
Now, some species of moths heavily rely on an aquatic environment to survive. They have adapted to such conditions and as such, are capable of living and breeding underwater. For them, water is an important part of their life, as they get food from water-dwelling algae and vegetation.
Do Moths Dissolve in Water?
Moths and other similar insects do not dissolve in water. They may have a frail body compared to other flying creatures on this planet, but they are not that fragile. They too possess a carbon-based skeleton and exterior. And carbon-based substances are not the easiest to dissolve in water.
Now, if you were to touch a moth’s wing, you might feel part of it coming off and sticking on your skin. This might give you the illusion that the creature is deteriorating. But that dusty or grainy substance is nothing more than the tiny scales or hairs we mentioned before.
These scales are very loosely attached to the moth’s body. So, they come off very easily. In fact, moths can shed their scales just by flying around and bumping into things. If a moth loses them while swimming in the water, this might give the (wrong) impression of a dissolving moth.
Do Moths Lay Eggs on Water?
Aquatic moths will lay their eggs underwater, typically on vegetation or any other spots that can provide adequate protection. All other species will lay their eggs in a dry environment under leaves, in cracks, or in crevices.
Adult aquatic moths do not live for much longer. Their main purpose is to find a mate so that they can continue their heritage. Adults need to stay dry but will hang around aquatic habitats for the most part. After finding a mate, the moth will return to the water. With the help of plastrons or air pockets, they dive into the depths and lay their eggs.
Now, remember that aquatic moths are sort of the exception to most of the moths you will commonly witness. The average moth will remain in dry areas and lay its eggs on trees or underneath foliage. So, moth eggs underwater are rare but it is something that happens.
Moths and their relation to water and rain continue to be an intriguing area of research for many scientists. And understanding this relationship will not only help us protect this diverse group of insects but also benefit mankind by helping us develop better tools.
Sources:
https://www.pnas.org/content/117/25/13901 (with more videos and pictures of water drops hitting moths)
