(On Strangler Figs)

Time to speculate:

Butterflies often use toxic plants as caterpillar hosts.  The larvae take up poisons from the host plant and become protectively poisonous, the safety shield carrying over into adulthood.  Monarchs feed on milkweeds able to stop a predator’s heart.   Pipevine and the Polydamas Swallowtails who eat them kill cells.   Zebra Longwings obtain cyanide from their passionvine.   Could go on, but we all get the point.   But now comes a minor mystery, the Ruddy Daggerwing Butterfly and Ficus.

For most common creatures the Internet reveals a ton of research.     But try that for the mysterious Ruddy Daggerwing Butterfly.  Yes, there are tidbits, but what the knowledge-seeker learns quickly it is how under-studied this beautiful creature is, at least via normal Internet snooping.   Maybe there’s deep research out there in dusty tomes or secret catacombs.

Its larval hosts are members of the fig genus, Ficus.   At least toward the northern part of the butterfly’s small range, mainly Strangler Fig.    The Daggerwing’s distribution and that of the Strangler Fig are virtually the same.

Do figs pass poisons to Ruddy Daggerwing caterpillars like those milkweeds, pipevines, and passionvines do to their caterpillar partners?  Ficus drips milky sap when broken, and in a general sense we don’t trust milky sap.   Also, you don’t often see much insect damage on Strangler Fig foliage.    But specifically, is there something nasty, and what might it be?

There might be something very insecticidal,  and to go farther we need some context on cholinesterase inhibitors.   Cholinesterase (colon-ES-ter-aze)  is a key enzyme in an insect’s and my nervous system.  Inhibit cholinesterase, and you inhibit nerve function.     They are central to today’s story.

Most of the late 20^th Century insecticides were cholinesterase inhibitors. So are certain military “nerve agents.” They kill bugs and humans.

Most attention in treating Alzheimers centers on cholinesterase inhibitors. They might be useful to humans when properly harnessed.

Most recent attention to the biochemistry of Ficus centers on its cholinesterase inhibitors in relation to potential Alzheimers treatments.

So then, it looks at a glance  that perhaps the Ruddy Daggerwing can tolerate and sequester the fig’s cholinesterase inhibitors as its own borrowed secret weapon.

Sounds good to me.  All that’s missing is evidence.