Great Diving Beetle: 15 Facts You Won’t Believe!


Share this article

The great diving beetle (Dytiscus marginalis) is a member of the Dytiscidae family of animals. These are aquatic beetles that are vociferous predators in nature and hunt smaller invertebrates. When this beetle feels threatened, the insect exudes a strong-smelling fluid from its anus to fend off predators. The larvae are larger than adults and look more fearsome. You can spot the adults because they keep the tips of the abdomen above the surface of the water to replenish the air that is stored under the wing cases. They come to the water surface in search of oxygen. Slow water bodies like ponds have plenty of air for the larva to live a healthy life. These beetles can be spotted in garden ponds and pools of still water. This insect is mainly spotted in the search for tadpoles in garden ponds.

If you like this article, then why not check out green dock beetle facts and lesser stag beetle facts?

Great Diving Beetle Interesting Facts

What type of animal is a great diving beetle?

The great diving beetle (Dytiscus marginalis) is a species of insect that belongs to the Dytiscidae family.

What class of animal does a great diving beetle belong to?

Like all other insect species, it is also a member of the Insecta class of animals.

How many great diving beetles are there in the world?

It is regrettable to say that not much data is available on the population density of this beetle in the world. It has been reported that the insect is quite widespread in Britain.

Where does a great diving beetle live?

The great diving beetle habitat is found in northern Asia and Europe. In the United Kingdom, the insect can be seen in England and Wales. Even southern Scotland has some occurrences of this beetle but you will not find as many as you do in northern parts of Scotland. These are the largest beetles that you will find in Ireland and England.

What is a great diving beetle's habitat?

A great diving beetle (Dytiscus marginalis) is seen to live in mountain pools and lakes. You may often find this insect in heaps of melted snow. Adult beetles are seen to be hibernating under stones during the colder times of the year in order to not become frozen. This insect is quite active in places around ice where it can use the oxygen bubbles present under the ice. They also use the dissolved oxygen on the water surface. Often you will find this species in garden ponds, especially ones with a lot of vegetation cover. These insects are found in freshwater areas having both slow running and still water like lakes and bogs.

Who do great diving beetles live with?

Though there is not much data available to determine whether a great diving beetle (Dytiscus marginalis) is a solitary insect or not, we know that beetles generally live in colonies. We can assume safely that this beetle also lives in colonies.

How long does a great diving beetle live?

The exact great diving beetle lifespan is not known to us. Most beetles usually live for about two to three years after birth. Most of this time is spent in the great diving beetle larvae stage with only a few weeks as adults.

How do they reproduce?

Great diving beetle (Dytiscus marginalis) mating takes place in the water. Metamorphosis takes place in these beetles as the insect lays the eggs underwater during the spring season. Each of the eggs is kept inside stems of submerged new plants in which special cavities are cut. After an incubation period of about 17-19 days, the eggs hatch and larvae emerge. In the summer, great diving beetle larvae undergo pupation on land for which it requires damp soil. They transform into adult diving beetles in the fall.

What is their conservation status?

The great diving beetle (Dytiscus marginalis) is Not Evaluated in the IUCN Red List of Threatened Species. We can say that there is no danger of extinction of this species at present. The insect is quite common and widespread.

Great Diving Beetle Fun Facts

What do great diving beetles look like?

A large aquatic insect, the great diving beetle (Dytiscus marginalis) at first glance may seem to be blackish-brown in color but it actually is olive-brown. The body has a yellow border around its thorax and head and it also has yellow legs. Females have ridged wing cases while males have smooth wing cases. Both the female and male have almond-shaped bodies. Great diving beetle larvae are much larger than adults with sharp jaws. They are even more voracious than the adults, indulging in cannibalism sometimes. The larvae do not have wing cases to store air from the water surface of ponds.

As it is a carnivorous insect, the larvae have a pair of jaws that secrete digestive enzymes in the body of their prey like tadpoles

How cute are they?

It is difficult to consider the insect as anything but cute.

How do they communicate?

Since beetles are now known to have good eyesight, they use other methods for communicating with members of the same species. They use vibrations and pheromones for communication purposes.

How big is a great diving beetle?

The adult great diving beetle size is about 1.2 in (3 cm) in length while a great diving beetle larva can grow as much as 2.5 in (6.4 cm). The size of great diving beetle larvae can be compared to the adult ground beetle whose length is almost the same.

How fast can a great diving beetle move?

This beetle can fly but the flight is restricted to the night so that it can evade predators like birds. Most of its movement occurs while swimming in the water but the exact speed is not known.

How much does a great diving beetle weigh?

An adult beetle weighs about 1.1 oz (30 g) which makes this species three times lighter than the water beetle having its weight falling in the range of 2.5-3.5 oz (70-100 g).

What are the male and female names of the species?

Male and female members of the species have no distinct names. The difference is that while the male has smooth wing cases, the female has ridged wing cases.

What would you call a baby great diving beetle?

A baby beetle is called a larva. It is a voracious carnivore like the adult version and has strong sharp jaws for catching its prey.

What do they eat?

The great diving beetle diet consists of fish and tadpoles. Both the larvae and adults are highly carnivorous insects who look out for their prey under the water in areas which light reaches. The larvae have sharp jaws which they stick into the body of their prey and pump digestive enzymes into it. As a result, the internal organs of the prey like tadpoles are sucked by the larvae. The larvae can become cannibalistic and consume other larvae. Small insects and newts are also food for the beetle.

Are they dangerous?

Though not poisonous, the great diving beetle is capable of giving a painful nip to human fingers. Since the larva can prey upon small fish and newts, it is no wonder that human skin will be easy to tackle for even young beetles.

Would they make a good pet?

Some people do keep beetles as pets but the great diving beetle is better suited for aquatic wild areas.

Kidadl Advisory: All pets should only be bought from a reputable source. It is recommended that as a potential pet owner you carry out your own research prior to deciding on your pet of choice. Being a pet owner is very rewarding but it also involves commitment, time and money. Ensure that your pet choice complies with the legislation in your state and/or country. You must never take animals from the wild or disturb their habitat. Please check that the pet you are considering buying is not an endangered species, or listed on the CITES list, and has not been taken from the wild for the pet trade.

Did you know...

Sucker pads are located on the front legs of male beetles which are used to clasp to the female while mating and also to grab invertebrates as food.

The larvae swims with an 'S'-shaped movement.

Are great diving beetles an invasive species?

No, they are not an invasive species.

Can diving beetles fly?

Yes, this beetle can fly but it flies at night to avoid being eaten by predators like birds. This way they colonize new water bodies like ponds and lakes. The great diving beetle wing is present in both males and females.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other arthropods from our eastern Hercules beetle facts, or giant stag beetle facts for kids.

You can even occupy yourself at home by coloring in one of our free printable beetle coloring pages.

Second image by Bernard Dupont from France

Subscribe for virtual tools, STEM-inspired play, creative tips and more

By joining Kidadl you agree to Kidadl’s and and consent to receiving marketing communications from Kidadl.