These Giant Insects Are Fascinating (and Terrifying)

Some of the world’s most important contributors are also the smallest. Insects might be a nuisance to us when they chew on leaves in our garden, bore holes into our fruit, or buzz around us relentlessly at a picnic, but without them, we would be missing out on a lot of the Earth’s joys. 

There are over ten quintillion insects alive today, consisting of over one million species worldwide. This makes up more than 70 percent of all animal species on the planet. Most of these insects are small and make their impacts felt by their large numbers, but what are the mega bugs in the world?

Today, giant insects, from butterflies to wasps to beetles, are alive. You won’t want to miss this collection of giant insects and invertebrates from the past to the present day!

The Largest Beetle: Titan Beetles (Titanus giganteus)

The titan beetle is the largest beetle in the world by body length. This beetle likes the rainforests of the Amazon. They can grow up to 6.6 inches long and their jaw is strong enough to tear at human flesh or snap small twigs. They use their jaws to defend against predators.

Scientists have never found a titan beetle larva. However, they have found holes in dead trees that they believe were created by these larvae. The larvae of titan beetles can reach up to one foot in length and be as wide as two inches, judging by the size of the boreholes.

A titan beetle flies around until it finds a mate and reproduces, just as the large atlas moth does when in its adult phase. It appears that no pupae have ever been found. They may reach maturity underground, amongst the roots and branches of plants. Before they pupate, they need to grow to a large enough size. 

Bright lights attract these beetles at night. French Guiana uses mercury-vapor lamps to attract male titan beetles. This region has an ecotourism industry built upon providing sightings of these beetles.

The Longest Insect: Stick Insects (Phasmatodea)

Stick insects are the world’s longest insects. They have evolved a bizarre shape to hide among branches, twigs, and foliage from predators. There are more than 3,000 species of stick insects in the world, divided into five families. Over 300 species are found in China. Stick insects are long and thin with nodes that resemble bamboo plants.

Compared to its Chinese name, the Greek name for the stick insect, phasma, implies something more imaginative: it translates as “phantom.” Asia has the most species of stick insects in the world. Some species have unusual or exaggerated colors. Many insect collectors and lovers aspire to own one.

The Heaviest Insects: Giant Wetas (Deinacrida heteracantha)

New Zealand’s remote location and long separation from other land masses led to fewer mammal species than other continents. With fewer predators, wetas evolved to large sizes. A giant weta can weigh more than 70 grams (about 2.47 ounces), making it one of the heaviest insects globally. They can weigh considerably more than a sparrow.

In addition to their long bodies, giant wetas have legs and antennae that measure about 4 inches long. They are excellent examples of island gigantism. Unfortunately, after the arrival of colonists in New Zealand, rodents decimated the weta population.

Though once prevalent across New Zealand’s northern island, some species of giant weta became extinct on mainland New Zealand in the 1960s. Today, certain giant wetas can be found only on Little Barrier Island, about 50 miles northeast of Auckland.

The Largest Wasp: Tarantula Hawks (Pepsis pulszkyi)

Tarantula hawks measure around two inches long. They are so large and vicious that they hunt tarantulas as a source of food. The tarantula hawk will lay eggs during the spider’s dwindling life so that the young can eat it when they hatch. A tarantula hawk’s wingspan is 4.5 inches, and it can grow up to 2.7 inches in body length. This makes tarantula hawks the largest wasp in the world.

There are more than 250 species of Pepsis in South America and 15 in the United States, with at least nine occurring in deserts. Tarantula hawks appear wherever tarantulas are found. Their only predators are roadrunners and nesting wasps.

The Largest Butterfly: Queen Alexandra’s Birdwings (Ornithoptera alexandrae)

The Queen Alexandra’s Birdwing butterfly has a wingspan that reaches 11 inches wide, making it the largest butterfly in the world. Tropical butterflies like this one live in lowland coastal rainforests in New Guinea.

Females are larger, have different patterns and coloration on their wings, and are different from males in size, color, and shape. Compared to the male, the female has longer brown wings with white markings and a cream-colored body with tufts of red hair on the chest.

Despite its localized distribution, Queen Alexandra’s Birdwings are extremely rare. There is one small strip of lowland coastal rainforest east of the Owen Stanley Mountains where this scarce and endangered butterfly can be found. The adult lifespan is about three months. 

Giant Insects of the Past: Prehistoric Insects that Grew to Incredible Sizes!

300 million years ago, the world was a much different place than today. It was an era before dinosaurs and some unusual animals were the largest on Earth. Specifically, invertebrates were among the largest creatures in the world.

The explosion of giant insects began during the Carboniferous period, which lasted from 359 million to about 299 million years ago. At the time, oxygen levels were significantly higher than found on Earth today, which fueled gigantism across a number of invertebrates.

In addition, insects and other bugs didn’t yet face the threat from birds, which had not yet evolved to roam the skies as predators capable of feasting on the largest insects in the world. As birds began appearing roughly 150 million years ago, insect sizes in the fossil record began plummeting. This just makes our modern giant insects all the more impressive!