Goliath Stick Insect

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Last night I was lucky to spot this female goliath stick insect (Eurycnema goliath) resting high in the canopy. As I shone my light on her, a tawny frogmouth (Podargus strigoides) landed on a nearby perch. I quickly extended my handy-dandy five meter long frilly noose and knocked the stick insect down before she became a delicious midnight snack… or a full-course meal. The landing was soft since she extended her transparent wings to slow her descent, and she immediately performed the deimatic display when I picked her up. With loud hisses, thrashes, and bright red stripes on the underside of the wings, I figured she must have learned something from the frillies. Unfortunately the goliath appeared to have already been in a clash with a predator, and fresh wounds were visible on her left maxilla and right hind leg. I kept her overnight and the wounds dried up, but after giving her water and eucalyptus leaves she seems rather weak. Her abdomen is thin and depleted of ova so I figure she has already laid and contributed to the next generation of goliaths in my field site. She dropped five last ova for me, very similar in appearance to acacia seeds, but it will likely take up to half a year for the nymphs to hatch.

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Giant insects are always jaw-dropping to find. Although this species is the not the longest phasmid in Australia (e.g. Ctenomorpha gargantua & Acrophylla titan), it is almost the length of my forearm. The beautiful pink/yellow/green mesothorax with cyan spikes and striped serrated edges on the legs give the insect a conspicuous armored look. However, this species resides in the canopy of the eucalypt forest and has the perfect morphological arsenal to remain undetected. They are almost impossible to spot among the dense leaves unless you are a pacific baza (Aviceda subcristata). The monsoon rains last week seem to have brought out all the insects, mosquitoes included, and photographing this goliath stick insect while being enveloped in hundreds of mosquitoes was more challenging than I anticipated. Shortly after I was able to snag a young juvenile frilly — probably one of the individuals I feel most attached to — and a large male frilly who made a racket with loud powerful tail whips before he came into my hands. All this just in time before a lightning storm caught me off guard and made me walk at an uncomfortable pace back to the car.

Photographed after disturbance [4] unless otherwise stated

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Last cool fact about the goliath. Supposedly they use their cerci (elongate extensions at the end of the abdomen) and ovipositor to flick excrement away from their feeding site. I’ve encountered large piles of saturniid caterpillar frass on the ground, so perhaps it’s another behavior to circumvent detection.

Photographed in situ [1]
Photographed in situ [1]
Photographed in situ [1]

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