Extatosoma, an early runner
The story of a young spiny leaf insect on an escape trajectory.
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This episodes uses the "Papuan/North Australian rain forest" soundscape, which I made using INaturalist recordings from user Tom Hunt. You can find full details and other soundscapes on the dedicated page.
Transcript
Picture yourself in an Australian jungle, in the middle of day.
[Australian jungle noise fade in]
Even though you are a stick insect, you are not yet in the canopy,
but a few centimeters underground, in an ant nest, still inside your
egg.
[Jungle noise muffles a bit]
It is getting about time to crack the egg, but you have a long
journey ahead of you… To reach the trees.
Hi and welcome to the Insect Insights, chill insect stories to relax
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your host, and I hope you are ready to dive into insect knowledge for
another weekly insight!
It might sound surprising to hear that an egg ended up in this ant
nest, but it is in fact rather common. Your egg bears a small structure,
full of fatty acids ants adore. This small knob, the capitulum, is
easily detachable, so ants can enjoy it without damaging your egg. They
simply carry it for a while, often leaving it inside their nest once
their snack is gone.
On one side, that give you safe condition to mature inside your
shell. On the other side, it causes the first instant of your life to be
complicated. So that the rest of yourself doesn’t end up as an ant-snack
as well, you need to run, and run fast. Instantly after you are out of
your egg, this is what you do. Run towards the light, and up.
Through generations and generations, hatchlings like you have been
selected to look and move like ants, while still running without a stop.
This made the escape slightly easier. If you make it out of the colony,
good news! Your ant mimicking traits are still very useful, as predators
usually don’t want to mess with ants. The other news is you are not done
running, as you are still on the ground floor, and you want to reach the
canopy.
More running, following the light and escaping gravity, for you.
Until your first moult in a few days, you will keep climbing up trees.
Even if you fall, you have tricks to glide down towards something you
can grab onto. You are a small dedicated being. Committed with behaviour
and morphology to one thing: going up.
Sources
Smart, H.R., Andrew, N.R. and O’Hanlon, J.C. (2023) ‘Ant mediated
dispersal of spiny stick insect (Extatosoma tiaratum) eggs and Acacia
longifolia seeds is ant-species dependent’, Australian Journal of
Zoology, 70(4), pp. 105–114. Available at: https://doi.org/10.1071/ZO22036.
Suetsugu, K. et al. (2018) ‘Potential role of bird predation
in the dispersal of otherwise flightless stick insects’,
Ecology, 99(6), pp. 1504–1506. Available at: https://doi.org/10.1002/ecy.2230.
Zeng, Y. et al. (2015) ‘Visual ecology of directed aerial
descent in first-instar nymphs of the stick insect Extatosoma tiaratum’,
Journal of Experimental Biology, 218(14), pp. 2305–2314.
Available at: https://doi.org/10.1242/jeb.109553.
Zeng, Y. et al. (2020) ‘Canopy parkour: movement ecology of
post-hatch dispersal in a gliding nymphal stick insect, Extatosoma
tiaratum’, Journal of Experimental Biology, 223(19),
p. jeb226266. Available at: https://doi.org/10.1242/jeb.226266.