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What is the World's Biggest Insect?

R. Kayne
R. Kayne

For sheer length, no other insect beats the female Giant Walking Stick (Phobaeticus serratipes) for the title of world's biggest insect. Found in Malaysia and Singapore, this insect looks like an assemblage of twigs and is perfectly camouflaged among the branches where it lives. The longest specimen on record was 21.8 inches (55.5 cm). Some people even keep these huge insects as pets.

The Giant Walking Stick may be long, but it doesn't weigh much. For that, it is necessary to turn to the giant scarab beetles. Among them, entomologists have settled on five contenders for world's biggest insect. The South American Longhorn Beetle (Titanus giganteus) of French Guiana makes perhaps the most impressive showing, with a body length over 6.5 inches (16.7 cm).

The Giant Walking Stick can be found in Singapore.
The Giant Walking Stick can be found in Singapore.

A shorter — but far thicker — competitor is the Acteon Beetle (Megasoma acteon) of South America. Males can grow to 5.3 inches (13.5 cm) long by 1.6 inches (4 cm) thick. The Elephant Beetle (Megasoma elephas) found in Mexico and Venezuela has a shorter body than the Aceton, but a longer snout, making its total recorded length 5.4 inches (13.7 cm). Bringing up the rear are two species of Goliathus: G. regius and G. goliatus, both measuring in at 4.3 inches (11 cm).

New Zealand is home to some unusually large insects.
New Zealand is home to some unusually large insects.

In 1874, the Rev. J. G. Wood published Insects Abroad, in which he claimed to have in his possession a 9 inches (22.8 cm) South American Longhorn Beetle. A specimen this large has never been documented since, and no one is quite sure what method he used to measure the bug. Therefore the accepted recorded length remains at 6.5 inches (16.7cms), which still leads the top five contenders.

Although the Giant Walking Stick wins for length, for sheer weight you'll have to turn to the giant wetas (Deinacrida heteracantha) of New Zealand. A pregnant female can top the scales at over 2 ounces (71 grams). Although not as heavy, the Australian Giant Burrowing Cockroach is one of the biggest cockroaches, often weighing between 1.05 and 1.23 ounces (30 and 35 grams).

There are well over 1 million insect species known, with an estimated 10 million still undocumented. The title of world's biggest insect remains a matter of how it is measured — by length or by weight.

Frequently Asked Questions

What is the world's biggest insect by wingspan?

The title of the world's biggest insect by wingspan belongs to the Queen Alexandra's birdwing butterfly (Ornithoptera alexandrae), which can boast a wingspan up to 1 foot (30 cm). This magnificent species is native to the rainforests of Papua New Guinea and is known for its vibrant coloration and impressive size.

Which is the heaviest insect on Earth?

The heaviest insect on Earth is the Giant Weta, specifically the Little Barrier Island giant weta (Deinacrida heteracantha), which can weigh as much as 71 grams (2.5 oz). This insect is endemic to New Zealand and has a remarkable resemblance to a large grasshopper.

Are there any extinct insects larger than the ones found today?

Yes, there were larger insects in prehistoric times. The largest known insect of all time is the extinct dragonfly-like Meganeura, which lived around 300 million years ago and had a wingspan that could reach up to 2.5 feet (75 cm), making it larger than any insect currently living.

How do scientists measure the size of insects?

Scientists measure insects by various metrics depending on the species' characteristics. Common measurements include wingspan for butterflies and moths, body length for beetles and stick insects, and weight for heavier insects like the Giant Weta. These measurements are taken using precise instruments and are crucial for entomological research and records.

Why don't we see insects as large as the Queen Alexandra's birdwing commonly?

Insects are limited in size due to factors such as the oxygen content in the atmosphere and their respiratory system, which relies on diffusion through spiracles and tracheae. Larger bodies would require more efficient oxygen transport systems. Additionally, their exoskeletons would need to be disproportionately heavy to support greater sizes, making it energetically unfavorable.

Is the world's biggest insect endangered?

Yes, the Queen Alexandra's birdwing butterfly is classified as endangered by the IUCN Red List. Its habitat is threatened by palm oil plantations, logging, and agriculture, which reduce the rainforest areas where it can live and breed. Conservation efforts are in place to protect this species and its environment.

Discussion Comments

Babalaas

@ PelesTears- You lived on the islands so you are probably familiar with many of the spiders that inhabit the island. The spiders on the islands are beautiful, but there is one big bugger that I do not care for much.

The cane spider is about the size of a tarantula, maybe bigger because they are flat and have longer legs. They are not venomous, but the females with egg sacks will charge at you if they feel threatened.

I learned this my first night on the Big Island. I went to stay with some family friends, and we decided to camp in their yard. They told us that there were no venomous snakes or insects to worry about so pitching a tent should be fine.

I woke up to something crawling on my chest. I looked down and saw though the little bit of moonlight a huge cane spider sitting on my chest. I freaked out and started thrashing around in my tent!

Everyone had a good laugh in the morning. They forgot to tell me about the giant spiders that made the neighboring cane field their home.

PelesTears

@ Anon3474- You make a good point about butterflies and moths as potentially being the largest insects because of their surface area.

I have never seen any of the bugs that you or the article mention (only in magazines), but I have seen a few large bugs. I lived in Hawaii for about five years and the islands are home to some of the biggest centipedes.

The giant centipedes on the islands are commonly found near banana trees or under rotting wood. They are probably only 8-9 inches long and 3/4 inches wide, but they look like they are about a foot long when they run at you. They are some of the meanest bugs I have ever come across, literally going out of their way to try and bite you. Their bites are pretty nasty too.

anon3474

I Keep both Giant Walking Sticks (Phobaeticus serratipes) and heaviest stick insect the Malaysian Jungle Nymphs(Heteropteryx dilatata) as pets in the same enclosure, and although the Jungle nymphs look big (can weight up to 65g) its the length of the giant walking sticks that draws your attention.

Although giant wetas are heavier than other insects, its the water holds their mass, so insects like other forms of life, should be able to grow much bigger in an aquatic environment, however its other factors like oxygen intake that restricts insect sizes, as they do not have a heart to pump blood around their bodies for gas exchange to internal organs and cells.

This is why Lepidoptera (butterflies and months) can be a contender for largest insects, as their large wings (massive in some species) do not need oxygen, so are not restricted in maximum wing size making them have many times more surface area than the giant stick insects and more than the giant beetles too.

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    • The Giant Walking Stick can be found in Singapore.
      By: syphrix
      The Giant Walking Stick can be found in Singapore.
    • New Zealand is home to some unusually large insects.
      By: Ruslan Olinchuk
      New Zealand is home to some unusually large insects.