Wildfile Q & A: What makes the holes in Alligator Flag Leaves?

alligator flag rolls

Q: What makes the orderly slits and holes in Alligator Flag leaves?

alligator flag rolls

A: The culprits are caterpillars.

When new leaves of the Alligator Flag (Thalia geniculata) first emerge, the leaflets are tightly rolled.

Once the leaves approach their mature length, they begin to unfurl. That’s why there are rarely small and large leaves on the same Alligator Flag plant.

Brazilian Skipper butterflies use Alligator Flag as their larval host plant, which means eggs are laid and caterpillars hatch. When the caterpillar feeds on a new, still-rolled leaf, it  bores through the leaf. Then the leaf unfurls and … voilá! There is a neat pattern of orderly little geometric holes in the leaf.

To make a comparison that’s easy to relate to, think back to making a chain of paper dolls or making snowflakes from a sheet of paper by folding the paper several times and making a few cuts with a scissors.

Unfold the paper and a nice chain of dolls or snowflake-like symmetrical pattern magically appears.

Nature just uses leaves and caterpillars instead of paper and scissors.

By Dick Brewer