In Quebec, the lethocère, still known as a giant water bug, is the largest aquatic insect. There are many species: the American lethocere, the nepe, the ranatre, the skater, the notonecte, the corise, etc. It has nothing to do with fleas or bed bugs.
Lethocerus live in streams. He leaves them only to mate or migrate.
But in this case, how can he be an enemy to man? What does he physically look like? What is its life cycle? What are his habits? How to avoid an assault of lethocères? And what if there are too many of them?
All professional answers to these questions can be found below.
Nom français | Léthocère d’Amérique |
Nom anglais | Giant water bug |
Nom latin | Lethocerus americanus |
Classe | Insectes |
Ordre | Hémiptères |
Famille | Bélostomatidés |

What does lethocere look like?
This giant water bug impresses by its size: 2.5 to 5 cm long, sometimes up to 6.5 cm depending on the species. It is brownish in colour.
His head has large compound eyes. Below is the rostrum, a short, pointed beak formed by stinger-sucker-type mouthpieces.
Its flattened body is very hydrodynamic, which helps it swim quickly and efficiently. The tip of its wings is both thick and opaque.
At the end of his abdomen is a short breathing tube. It consists of two flexible pieces that can retract and make back-and-forth movements.
Its paws, covered with hair, end with a sharp, sharp claw. The earlier ones, folded forward, were designed to capture and retain prey.
What is the life cycle of lethocère?
Mating takes place on hot summer nights. The female lethocère lays up to 150 pale brown eggs during the breeding period, between May and June. Then it attaches them to the aquatic vegetation.
But note that females of some species lay their eggs on the male’s back. The latter then transports them until they hatch.
The lethocera or giant water bug is a gradual metamorphosis or hemimetal insect. So the young, coming out of the egg, already looks like the adult, the size and wings less. It will have to undergo five successive moults before reaching the adult stage.
It is at the penultimate moult that the drafts of wings appear. The adult will see each other between June and November.
Appeler René Gélinas Votre exterminateur local, Expérience et intégrité dans la gestion parasitaire
Tel 514 830 2819
Hantavirus, definition and mode of transmission
Hantavirus is a severe lung syndrome caused by a virus. It is secreted in the urine, feces and saliva of infected animals. Most often these are rodents. When humans come into direct or indirect contact with these secretions, the virus is transmitted to them. Ditto when they are bitten by infected rodents.
However, the virus is not transmitted from human to human, only from animal to human. This type of disease is called zoonoses because they can only be transmitted to humans through an animal. It has been found that domestic animals (apart from the domestic rat) and livestock cannot contract hantavirus so there is every reason to believe that only rodents can carry it.
Symptoms of hantavirus
Being a lung disease, one of the characteristic symptoms of hantavirus is difficulty breathing. At the beginning of the disease, the infected person begins to feel fever, chills, headache and muscle pain.
It is about two weeks after the appearance of the first symptoms that they are usually accompanied by a feeling of shortness of breath. Nevertheless, this last manifestation of the disease can be observed after two days as after six weeks; it depends on the organism of the individual.
Hantavirus can also lead to kidney disease or infection. And although they are rare and very few people are prone to them, there is currently no treatment to combat these ailments. It is therefore better to be careful not to contract them.
Is the multiplication of lethocères a risk to humans?
The giant water bug lives in fresh water, in ponds, calm bodies of water, and lakes.
Its menu is very varied: other insects, slugs, tadpoles, fry and small fish much larger than it, snails, salamanders, juvenile turtles, etc.; and it uses its mouthpieces to penetrate its prey and suck up their contents.
Its larva is cannibalistic. She can eat smaller larvae.
In winter, the insect remains lurking in mud and plant debris at the bottom of ponds and lakes.
Adult lethocers fly at night to gather for mating or short migrations.
When they travel, they are attracted to powerful sources of light: streetlights, sports field projectors, home lighting, etc.
They then turn around until they are exhausted, fall and end up on the lawn and in the pools.
These giant water bugs are completely harmless to humans and pets. Nor do they destroy the cultures and structures of our homes.
But if they are manipulated or walked on them, they sting with their rostrum under their heads; and this sting remains painful for four hours of time. It causes local swelling more or less depending on the amount of saliva injected.
This is why it is not recommended to let young children have fun with a lethocer.
6 Tips from a Professional Exterminator to Avoid Lethocera Invasion
Here are some tips to prevent the infestation of lethocers or giant water bugs:
- If you live near a stream, seal your windows. So you won’t find these insects inside your home,
- Clean your pool once a week to prevent recurrence of infestation,
- Get rid of their food source,
- Use a large dose of chlorine,
- Use borax, a mineral species of hydrated sodium borate. Borax kills aquatic insects. Sprinkle it around your house,
- Use insecticides in the form of lozenges. Example of the algicide.
But beware, lethocers are resistant to many products. If, despite your best efforts, your home remains colonized by these large insects, it is better to call in a professional exterminator.
How to get rid of the giant water bug: the solutions of the professional exterminator

The exterminator:
- Use your pool skimmer to remove lethocers from the pool surface. Then he kills them,
- Increases the amount of chlorine to shock the giant water bug,
- Use a pool vacuum cleaner to remove any trace of the insect,
- Filters water to remove algae and other growths that can be used as food or shelter for lethocers,
- Turn on the lights around your pool to dislodge lethocers that can fly around,
- Wash the pool.
But watch out for amateur exterminators. The true lethocère professional:
- Owns a permit from the Quebec Ministry of Sustainable Development with the label C5: Extermination. This means that it exterminates giant water bugs in compliance with Environment Canada regulations.
- Provides you with a certified professional technician in extermination and experienced in the task. The latter quickly comes to the scene of the attack, measures the degree of infestation, and finds the source.
He then offers you an appropriate treatment, and then trains you in the arrangements to make sure that you no longer suffer from an epidemic of lethocera or giant water bugs in the future.
- Intervenes discreetly. For example, it uses unidentified vehicles.
- You sign a written guarantee on the effectiveness of his treatment againstlethocer attack.
That’s the gist of what you need to know. And you, have you been the victim of an invasion of lethocères? What did you recognize as giant water bugs? How did you get rid of it? How did you end up with them? Tell us about your experience in the comments below.