caterpillars!

Papilio machaon (Swallowtail)

Foeniculum vulgare (Fennel)

Last update: 29 August 2023


Uncommon

Location Krimpen aan den IJssel, garden
Observations
2023-VIII-22


Macrophotography includes being idle for longer times; waiting in position near a nest for the return of the subject. Such an intermezzo offers chances as well of risk. Chances to take in the direct environment from a stationary position which frequently leads to new observations, risks because one can get distracted and miss the real goal.

Here I lay in position waiting for the return of a new digger wasp species on the bee hotel when my eye spotted a medium size Swallowtail (Papilio machaon) caterpillar in Fennel (Foeniculum vulgare). Possibly the adult that passed by earlier this year was a new guest depositing some eggs. Temptation rose but the target had been selected and position was kept. A day later the caterpillar stil remained in the same location and finally at dusk when the wasp suspended her activities for the day there was a chance to photograph the larva.

I wondered whether this 4th instar was about the mould as it remained motionless in the same posture. The thought hadn’t even fully materialized as the caterpillar jolted into motion and shed its old skin.
The old head shield remained hanging from the much larger new face of the caterpillar though the ordeal, only to be removed separately after the skin had been removed completely. Unfortunately I was too late to catch the shield as it dropped to the ground.

Swallowtail (Papilio machaon), 5th instar caterpillar on Fennel (Foeniculum vulgare)

The first animation shows how caterpillaric movement combined with small steps suffices to push the old skin backwards. In the second animation the caterpillar sheds the old head shield.

Swallowtail (Papilio machaon) 5th instar caterpillar sheds skin
Swallowtail (Papilio machaon) 5th instar caterpillar removes its old head shield

Literature

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