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).
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).
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.