Australia's (and Probably the World's) Longest Insect

Ctenomorpha gargantua Brock & Hasenpusch, the Gargantuan Stick-Insect, is no doubt one of the world's longest insects. Females measure more than 50 cm from the tip of the outstretched forelegs to the tip of the cerci (claspers). The longest specimen known measured in excess of 60 cm. The one figured here is around 55 cm. Males are considerably smaller, measuring about 30 cm.

C. gargantua occurs along the coast in rainforests from the vicinity of Cairns and Kuranda and the Atherton Tableland south to Mourilyan, Queensland. Males frequently fly to light. They are probably abroad at night in search of females. Females are rarely encountered. The likely reason is that they are short-winged and heavily bodied and less likely to attempt to fly unless greatly disturbed. They remain motionless in the tree tops. Because of their size, they would be attractive morsels for birds and lizards should they take to the wing. (The Pacific Baza, or Crested Hawk, Aviceda subcristata, is known to have a fondness for stick insects). Attempts at rearing the species from eggs is fraught with disappointment. Males seems to be able to make it through the developmental stages, but females encounter problems moulting in the latter stages. This may be associated with diet or, perhaps, humidity. In any even, the Gargantuan Stick-Insect is one of the north-western rainforest's treasures and most people living in the rainforest probably have no idea that these giants are among them.

Thanks to Paul Brock for comments.

Adult female Ctenomorpha gargantua. Note short wings.

Adult male Ctenomorpha gargantua. Note the longer wings and more slender body.